IPAP 15-3 MICROBIOLOGY MODULE 4
i. Best method of controlling parasitic life cycle ii. Application of latrines iii. Avoid spreading of raw fecal waste on soil
(a) Proper disposal of human and animal waste
i. Treatment with chlorine or iodine ii. Prevention of contamination of ground water
(b) Purification of drinking water
i. Cooking or heating: 1 hour at 55°C ii. Freezing: 20 days at -10°C
(c) Processing and treatment of food supply
i. Location of house ii. Housing construction: Elimination of vector breeding sites
(d) Improvement of housing quality
EXAM #4 REVIEW
25 questions on specimen/lab lesson and 25 questions on parasitology
THERE WILL BE MORE THAN 2 TERMS
ADD THEM HERE
It's problematic because Neisseria gonorrhea is a gram negative diplococcus.
Are genital tract commonly Gram stained?
No
Are there any normal flora in the CSF?
A reinfection in which the host is its own source of infection from a source already present in the body
Autoinfection
i. Water will destroy trophozoites ii. Water may contain free-living organisms that can complicate diagnosis iii. Urine may have an adverse effect on the motility of trophozoites
Avoid contaminating your poop with these things:
structures on the wall of the membrane of the hydatid cyst Echinococcus
Brood capsules
The amoebas
Class Lobosea
Largest subclass Found in every major organ Includes all trematodes which parasitize man Hosts: Intermediate, reservoir, and definitive
Class Trematoda -Subclass Digenea
The flagellates
Class Zoomastigophora
Most infections with Dipylidium caninum are asymptomatic. Pets may exhibit behavior to relieve anal pruritis (such as scraping anal region across grass or carpeting). Mild gastrointestinal disturbances may occur. The most striking feature in animals and children consists of the passage of proglottids. These can be found in the perianal region, in the feces, on diapers, and occasionally on floor covering and furniture. The proglottids are motile when freshly passed and may be mistaken for maggots or fly larvae.
Clinical presentation of Dipylidium caninum?
Sparganosis can produce painful inflammatory tissue reactions and nodules. Tissue reaction in eye is very painful, and usually causes periorbital edema. May cause development of corneal ulcers. Ocular disease is often associated with use of frog or snake flesh as a poultice over a wound near the eye.
Clinical presentation of Spirometra species?
Hepatic duct Asia
Clonorchis sinensis
Symbiotic relationship in which the parasite is benefited and the host is neither benefited nor harmed
Commensalism
Trichomonas or Candida Wet prep. microscopic exam of discharge
Copious amounts of vaginal discharge may indicate what?
CDC's immunoblot assay with purified Taenia solium antigens: immunodiagnostic test of choice for confirming a clinical and radiologic presumptive diagnosis of neurocysticercosis (acknowledged by World Health Organization and the Pan American Health Organization) Can use serum or CSF for testing More specific and more sensitive than enzyme immunoassays (EIAs)-tend to cross-react with antibodies to Echinococcus and filariasis
Cysticercosis immunoblot.
Obstruction Host reactions Lost nutrients Lost of fluids Dehydration
Damage caused by parasites
form within original mother cysts Echinococcus
Daughter cysts
(a) Nuclear membrane separates nucleus from cytoplasm (b) DNA composed of paired, linear chromosomes (c) Reproduction by binary fission and mitosis (d) Energy produced in mitochondria
Definition of Eukaryotes
The host that harbors the adult *or* sexually reproducing stages of a parasite
Definitive host
taeniasis and not cysticercosis.
Demonstration of Taenia solium eggs and proglottids in the feces diagnoses?
Eggs or gravid proglottids
Diagnostic form of Taenia saginata?
Separate male and female organisms
Dioecious
in the Northern Hemisphere (Europe, North America, and Asia) and in South America (Uganda and Chile). (Cases of D. latum infection associated with consumption of imported fish have been reported in Brazil.)
Diphyllobothriasis occurs where?
B12 deficiency
Diphyllobothrium latrum
"Fish" or "Broad tapeworm" Largest human tapeworm (up to 10m long) Other species that infect humans (less frequently): D. pacificum D. cordatum D. ursi D. dendriticum D. lanceolatum D. dalliae D. yonagoensis
Diphyllobothrium latum
Procercoid
Diphyllobothrium latum larval form developed from coracidium?
Known as "pumpkin seed" tapeworm due to shape of mature proglottid 25 eggs in packet
Dipylidium caninum
1. Gravid proglottids are passed intact in the feces or emerge from the perianal region of the host 2. Subsequently, they release typical egg packets On rare occasions, proglottids rupture and egg packets are seen in stool samples. Following ingestion of an egg by the intermediate host (larval stages of the dog or cat flea Ctenocephalides spp.), an oncosphere is released into flea's intestine. 3. The oncosphere penetrates intestinal wall, invades insect's hemocoel (body cavity), and develops into a cysticercoid larva. 4. The larva develops into an adult, and the adult flea harbours infective cysticercoid. *5. Vertebrate host becomes infected by ingesting adult flea containing the cysticercoid* 8. In small intestine of vertebrate host, cysticercoid develops into adult tapeworm which reaches maturity about 1 month after infection. The adult tapeworms (measuring up to 60 cm in length and 3 mm in width) reside in small intestine of host, where they each attach by their scolex. They produce proglottids (or segments) which have two genital pores (hence the name "double-pored" tapeworm). 1. Proglottids mature, become gravid, detach from tapeworm, and migrate to anus or are passed in stool (1).
Dipylidium caninum life cycle?
Worm consists of scolex with four sucking discs and double row of hooklets Strobila consists of three proglottids: one immature, one mature, and one gravid
Echinococcosis physical characteristics
Human echinococcosis (hydatidosis, or hydatid disease) is caused by larval stages of cestodes (tapeworms) of genus Echinococcus Echinococcus granulosus causes cystic echinococcosis, the form most frequently encountered E. multilocularis causes alveolar echinococcosis E. vogeli causes polycystic echinococcosis E. oligarthrus is an extremely rare cause of human echinococcosis
Echinococcus species
A parasite living on the external surface of the host
Ectoparasite
the proglottids are passed with feces
Eggs contained in gravid proglottids are released after
A parasite living inside the host
Endoparasite
Used to detect parasites, protozoa and helminths, in the upper part if the small intestine Do not eat 12 hours prior to testing The end of the string is taped to your cheek or neck A capsule containing the remainder of the string is swallowed -Worms -Larval forms -Giardia
Enterotest-string test
can cause ocular, cardiac, or spinal lesions with associated symptoms.
Extracerebral cysticercosis
Normally free living organism but may become an opportunistic parasite
Facultative parasite
Francesco Redi
Father of parasitology
Can be delayed for several hours or longer, but should be examined on the same day of submission
Formed specimens
Human infections have been reported in Europe, the Philippines, China, Japan, Argentina, and the United States.
Geographic distribution for Dipylidium caninum?
The genus Spirometra occurs worldwide in distribution, although most human cases of sparganosis are recorded from southeast Asian countries. Sparganosis is endemic in animals throughout North America, although human cases from this area are rare.
Geographic distribution of Spirometra species?
near lower end of worm, capable of reproduction
Gravid proglottids
Any living organism, animal or plant that harbors or nourishes another organism
Host
Specimen of choice is feces: FEA Complement fixation, intradermal test Identification form: Ova Size: 30 x 15μm Shape: Vase-like Color: Yellowish brown Operculum: Present, pronounced Content: Asymmetrical miracidium, "boxer's glove" appearance Abopercular comma: May be seen Broad opercular shoulders
How are Clonorchis sinensis ova identified?
Size: Up to 95 x 55μm Shape: Oval Color: Golden brown Operculum: Present at broad end Content: Yolk mass, variable size of granules in the yolk Abopercular thickening
How are Paragonimus westermani ova identified in the lab?
Size: 10 to 14 mm long by 3 to 5 mm wide Shape: Oval body Color: Reddish-brown Intestinal ceca: Undulating Testes: Deeply lobate and para
How are adult Paragonimus westermani identified in the lab?
Collected in clean, wide mouthed containers (a) Disposable cardboard containers with wax coating and tight-fitting lid: Container of choice i. Prevents leakage ii. Prevents loss of moisture (b) Plastic containers with Snap-On or screw-on lids: Do not retain moisture as well as cardboard (c) Glass containers: More expensive and breakable
How are fecal specimens collected?
Size: 85 x 60μm (medium) Shape: Ovoid Color: Yellowish-brown Content: Miracidium Spine: Inconspicuous, lateral
How are the ova of Schistosoma japonicum identified?
No operculum Spine location/size chief characteristic
How are the ova of Schistosomes identified?
(a) Proper disposal of human and animal waste (b) Purification of drinking water (c) Processing and treatment of food supply (d) Improvement of housing quality (e) Elimination of intermediate host(s) or vectors
How do we interrupt the parasitic life cycle?
Insert swab into mouth, start at one tonsil area, swab across to other tonsil area focusing on hot spots that you identified in previous visual inspection. Don't make the mistake of undercollecting, even if it makes patient uncomfortable. Don't touch the forward part of the mouth. Be sure to use a tongue depressor to prevent tongue from reflexing and causing contamination. Touching uvula accidentally okay, but not tongue or forward part of the mouth. *Adequate quantity*
How do you collect a proper throat swab?
Palpate to locate vein Cleanse collection site with 70% alcohol Cleanse collection site with povidone-iodine or tincture of iodine for 1 to 2 minutes *Disinfect bottle stopper in same manner* Do not touch the disinfected venipuncture site except with disinfected gloved finger
How do you decontaminate the collection site for blood cultures?
Count the number of primary uterine branches to determine the species T. solium: 7-13 T. saginata: 12-30
How do you speciate Taenia specimens?
Transport of specimens of Chlamydia Inoculate culture/transport medium according to kit instructions
How do you transport suspected Chlamydia specimens for culture?
Transport of specimens suspected of N. gonorrhoeae (for culture) -Inoculate transport medium immediately, e.g "Z" streak Thayer-Martin media, etc. -Supply CO2 -Prevent chilling
How do you transport suspected N. gonorrheae specimens for culture?
Routine -- initial Gram stain and culture for recovery of all bacteria, but not yeast or viruses Request India ink wet preparation microscopic exam if Cryptococcus is suspected
How is CSF processed in the lab?
Praziquantel* Adults and children: 5-10 mg/kg orally in a single-dose therapy (*Note: praziquantel should be taken with liquids during a meal.)
How is Diphyllobothrium latum treated?
Prevention is key to controlling ~osis: Washing hands and cooking utensils and proper personal hygiene when in environments inhabited by dogs. Dogs should not be in vicinity of animal slaughter or fed viscera of slain animals. Some area have killed stray dogs to reduce the infection potential
How is Echinococcis controlled?
The diagnosis of ~ or hydatid disease relies on clinical, radiographic, and serologic findings. Radiologic examination, scanning procedures, CT, and ultrasound techniques may provide first evidence of the cyst's presence. Aspiration of cyst contents may demonstrate presence of the protoscolices (hydatid sand); however, it is contraindicated because of risk of allergic response (anaphylaxis) and spread of the infection. Serologic testing may be useful, but results are negative in 10% to 40% of infections.
How is Echinococcus diagnosed?
The diagnosis depends on the demonstration of eggs in stool specimens. Concentration techniques and repeated examinations will increase the likelihood of detecting light infections.
How is Hymenolepsis diagnosed?
Specimen of choice is sputum (also feces) Sputum examination FEA (formalin-ethyl acetate) Other laboratory tests Immunodiagnostic test: ELISA; immunoblot; monoclonal antibody X-ray diagnosis Biopsies
How is Paragonimus westermani identified in the lab?
Diagnosis is usually made by the recovery of a sparganum from infected tissue. The presence of a sparganum is diagnostic and identication to the species level is usually not warranted.
How is Spirometra diagnosed?
praziquantel or albendazole Concomitant steroid administration may minimize inflammatory response to dying larvae. Surgical removal of cerebral and ocular cysts may be necessary. Prevention is key to control of human infection with controlled waste (feces) disposal. Which will also reduce the infection in pigs.
How is Taenia solium treated?
Surgical resection of cyst is treatment of choice. Sometimes, cyst is first aspirated to remove fluid and hydatid sand, and then it is instilled with formalin to kill and detoxify remaining fluid; finally, it is rolled into a marsupial pouch and sewn shut. Drug therapy with high-dose albendazole, mebendazole, or praziquantel may be used if the condition is inoperable because of the cyst's location.
How is cystic echinococcal disease treated?
EIA / ELISA, 24-48 hr cell culture
How is herpes diagnosed in the lab?
Microscopic identification of eggs in the stool is the basis of specific diagnosis. Eggs are usually numerous and can be demonstrated without concentration techniques. *Operculated Knob on shell at bottom* Examination of proglottids passed in the stool is also of diagnostic value.
How is lab diagnosis of Diphyllobothrium latum achieved?
Any number in specimen collected by aseptic means -- probable infection
How many bacteria must be present in an aseptic specimen to indicate infection?
1,000-2,000 (each proglottid contains thousands of eggs)
How many proglottids per Taenia worm?
Use 2 swabs or as directed by kit instructions For PCR - Collect & transport according to kit instructions (may be urine specimen)
How many specimens do you collect for N. gonorrhea and Chlamydia?
Should be examined within 30 minutes from time of passage (type of specimen where trophozoites may be found)
How quickly should liquid and diarrheic specimens be examined?
Refrigerator not freezer
How should you preserve poop?
formed when daughter cysts and brood capsules disintegrate and liberate the protoscolices
Hydatid sands
20-60cm long Scolex lacks hooklets Egg Larger than H. nana Bile stained No polar filaments *Requires larval insects "mealworms" to reach infective cysticercoid stage* Proglottids overlap each other
Hymenolepis diminuta
while less frequent, has been reported from various areas of the world.
Hymenolepis diminuta
Eggs passed from human feces Ingested by arthropod or intermediate host Oncospheres hatch in insect Cysticerci in insect body are ingested by humans/rodents Reaches adult form in humans
Hymenolepis diminuta Life Cycle
"Dwarf tapeworm" 2-4 cm long Egg Six-hooked embryo Polar filaments Scolex Four muscular suckers Crown of hooklets
Hymenolepis nana
is most common cause of all cestode infections, and is encountered worldwide. In temperate areas, its incidence is higher in children and institutionalized groups.
Hymenolepis nana
Autoinfection
Hymenolepsis nana is capable of what?
INSERT COLLECTION DEVICE QUESTIONS ON SWABS BASED ON .PDF
IF ANY
collect w/in 3 days after onset of symptoms
If we are collecting a sample to culture the virus, when should we collect it?
hexacanth
In the egg
how the parasite invades the human body.
Infective mode
the entrance which the parasite invades the human body.
Infective route
a stage when a parasite can invade a human body and live in it.
Infective stage
That host which harbors the immature, larval, or asexually reproducing forms of a parasite
Intermediate host
Typically no, because there are so many normal flora of same morphology
Is it useful to do a Gram stain on a throat specimen?
No (3 specimens over 6-10 days)
Is one negative stool sample enough to rule out parasites?
Multicellular higher animals
Kingdom Animalia
Length of adult worms T. saginata: 5m or more (may reach up to 25m) T. solium: 2 to 7 m
Length of adult Taenia worms?
the process of a parasite's growth, development and reproduction, which proceeds in *one or more different host depending on the species of parasites.*
Life cycle
Adult members of genus Spirometra live in intestines of dogs and cats (7). Eggs are shed in feces (1) and embryonate in environment (2). Eggs hatch in water and release coracidia (3), which are ingested by copepods. The coracidia develop into *procercoid/Sporanga* larvae in copepod intermediate host (4). Second intermediate hosts, including fish, reptiles and amphibians, ingest infected copepods and acquire procercoid larvae. Procercoid larvae develop into plerocercoid larvae in second intermediate host (5). Cycle is completed when a predator (dog or cat) eats an infected second intermediate host (6). Humans cannot serve as definitive hosts for Spirometra spp., but serve as second intermediate hosts (8)and develop sparganosis. Humans acquire sparganosis by either drinking water contaminated with infected copepods or consuming the flesh of an under-cooked second intermediate host (eating raw tadpole, frog, and snake flesh lead to infection). Spargana can live up to 20 years in the human host.
Lifecycle of Spirometra?
Escherichia coli Traveler's Diarrhea (ETEC) EHEC - ground meat Staphylococcus aureus -- food poisoning -- pre-formed, heat-stable toxin Clostridium perfringens -- food poisoning (spore germination) Norovirus (Norwalk virus) Adenovirus Rotavirus (infants) Other bacteria, viruses, and toxins
Listed by prevalence or no?
(a) Antacids (b) Antidiarrheal compounds (c) Mineral oil (d) Barium Sulfate (1-2 week wait) (e) Antibiotics (1-2 week wait)
Medicinal substances the ingestion of which may interfere with parasitological specimen examination
Reproductive organs of male and female in one organism or segment
Monoecious
nonoperculated and contain hexacanth embryo (exception - Diphyllobothrium latum)
Most cestode eggs are
2
Most trematodes (except schistosomes) have how many intermediate hosts?
Symbiotic relationship in which both parasite and host are benefited
Mutualism
can cause diverse manifestations including seizures, mental disturbances, focal neurologic deficits, and signs of space-occupying intracerebral lesions. Death can occur suddenly. (ASW Taenia solium)
Neurocysticercosis?
Stool specimens
O&P
Cannot survive in a free living state
Obligatory parasite
Oncospere - six hooked larval form released when egg hatches
Outside the egg
Symbiotic relationship in which one organism, the parasite, is metabolically dependent on another organism, the host; the host may or may not be harmed in the relationship
Parasitism
A host that serves as a transport host in which the parasitic forms undergo no development, but passes on to the final host
Paratenic host
Gram negative rods like normal flora
Pathogenic bacteria of the GI tract are mostly what morphology?
A parasite that harms the host
Pathogenic parasite
evaluated serologically since autoinfection, resulting in cysticercosis, can occur.
Persons who are found to have eggs or proglottids (Taenia solium) in their feces should be what?
Within subkingdom Eukaryota; contains malaria and coccidians
Phylum Apicomplexa
Roundworms/Nematodes
Phylum Aschelminthes
Within subkingdom Eukaryota; contains the ciliates
Phylum Ciliophora
Within subkingdom Eukaryota; contains the microsporidia
Phylum Microspora
(a) Class Trematoda: The flukes (b) Class Cestoda: The tapeworms
Phylum Platyhelminthes: Flatworm
Within subkingdom Eukaryota; contains most pathogenic protozoa
Phylum Sarcomastigophora
Scotch tape prep
Pinworm
Human Metapneumovirus - pneumonia Parainfluenza virus -- croup, bronchitis (children) Influenza virus Respiratory Syncytial Virus Adenovirus
Pneumonia viruses?
Drug of choice for treatment of active taeniasis (Can rupture cysts -Praziquantel is cysticidal and can cause inflammation around dying cysts in those with cysticercosis, which may lead to seizures or other symptoms. (Niclosamide Alternative to Praziquantel)
Praziquantel
(segments)-forms body (Carry both testes as ovaries - a sexual-function body)
Proglottids
(a) Prophylaxis when entering into highly endemic areas (b) Immunization against parasite infective forms
Protection
tapeworm heads that develop in brood capsules Echinococcus
Protoscolices
A host which replaces man in the life cycle of the parasite
Reservoir host
pointed end of scolex that has points of attachments (suckers, hooklets, etc.)
Rostellum
Through host tissues, skin or mucous membranes (a) Remains on or within the epidermis or subcutaneous tissues (b) Penetrates to other host organs or tissues
Route of infection - Active penetration
Transmission of parasites across the placental barrier from mother to fetus
Route of infection - Congenital
Oral (nasopharyngeal) in food, water or aerosols, etc. (a) Remains in gastrointestinal tract (b) Internal migration to other host organs or systems (c) Migration through other host systems and return to gastrointestinal sites
Route of infection - Ingestion
Through host tissues by vector or agent (a) Arthropod-borne: By mouth parts, salivary glands, or waste products (b) Transfusion: Present in donor blood at time of transfusion
Route of infection - Injection
Cannot (Microscopic identification of gravid proglottids (or, more rarely, examination of the scolex) allows species determination.) (Eggs of Taenia spp. are also indistinguishable from those produced by cestodes of the genus Echinococcus (tapeworms of dogs and other canid hosts))
Saginata and Solium can/cannot be differentiated by ova in microscopy?
(head)- differ in number and placement of suckers and presence or absence of hooklets
Scolex
Pinworm eggs (Enterobius vermicularis) are deposited around the perianal region This method gives best recovery of eggs if used before defecation, bathing or dressing in the morning Firmly press the sticky side of tape to the skin around the folds of the anus
Scotch tape prep (clear tape, not cloudy)
Exposure, not necessarily infection
Seroprevalence indicates what?
Examined within one hour of passage
Soft specimens
ribbon-like larval worm in flesh of freshwater fish (plerocercoid)
Sparganum
chain of proglottids
Strobila
Monitoring of incidence, prevalence, distribution and severity of disease
Surveillance
Two organisms of different species living together
Symbiosis
1. Eggs or gravid proglottids in feces passed to environment 2. Cattle ingest contaminated vegetation 3. Oncospheres hatch, penetrate intestinal wall and circulate to musculature 3a. Oncospheres develop into cystocerci in muscle 4. Humans infected by ingesting raw or undercooked/infected meat Adults in small intestine
Taenia saginata
worldwide in distribution
Taenia saginata and T. solium are
in poorer communities where humans live in close contact with pigs and eat undercooked pork.
Taenia solium is more prevalent
(a) Protection from infected persons: Isolation (b) Curative therapy: Antiparasitic drugs i. Antimalarial: Chloroquine phosphate (Aralen) ii. Antihelminthic: Praziquantel (Biltricide) iii. Antiprotozoal: Metronidazole (Flagyl)
Therapeutic measures
Upper Respiratory Tract
These are the normal flora of what body site? Alpha & gamma Streptococcus (GPC) Neisseria spp (GNDC) Staphylococcus spp (GPC) other than S. aureus Corynebacterium spp (GPB) other than C. diphtheriae (various anaerobes)
A carrier, usually an arthropod, which transmits an infective form of the parasite from host to another
Vector
20 to 30 mL (1 to 5 mL for pediatrics) *Blood to broth ratio of 1:10* *Do not change needles between bottles* If syringe is used, be careful not to allow vacuum to pull all blood into first bottle Mix by inverting bottle Cleanse site with alcohol to remove iodine Immediately transport bottles to lab w/o refrigeration
What are blood collection guidelines for culture?
Collect from the port high on tubing; NOT from collection bag Handle & interpret as collected by aseptic means Catheterization is usually contraindicated if purpose is only for urine specimen collection - often causes nosocomial infection
What are collection guidelines for urine collected from an indwelling catheter?
If pyuria exists, 50,000 CFU/mL may indicate infection
What are colony count considerations when there is pus?
Representative of the infection Sufficient quantity Prevent excessive contamination Prevent (limit) contact with air if anaerobes suspected
What are good specimen characteristics?
keep bacteria moist
What are humidity requirements for specimen transport?
Prior to initiating antimicrobial therapy Multiple samples -Fecal & sputum -- 1 per day for 3 days -Blood culture - 3 (within about 2 hr)
What are ideal collection times for specimens?
Influenza virus Cold viruses - Rhinovirus, Respiratory Syncytial Virus (RSV), Corona virus Adenoviruses Parainfluenza virus (cold-like)
What are other predominant pathogens of the URT?
5. Hand washing 6. Education of exposed populations
What are some other methods of control of parasitic life cycle interruption?
Anaerobic Fungi or slow growing bacteria
What are special request culture types for blood?
Collect as directed by kit manufacturer Inoculate scrapings & fluid into cell culture (or PCR transport media) Transport specimens -- inoculate culture/transport medium according to kit instructions
What are specimen collection guidelines for suspected herpetic lesion or genital wart?
Collect using needle aspiration or swab Transport within 2 hours Process for "tissue abscess" bacteria (not STD) culture on non-selective media
What are specimen collection guidelines for suspicion of other genital tract bacteria (Staph, Strep, E.coli, agents of PID, other) [not STD]?
Rayon or Dacron (not cotton) Some foam products provide better adherence of specimen Cytology brush with soft bristles
What are swabs made from?
Routine -- room temp. or refrigerate Special -- *do NOT refrigerate if Neisseria, Haemophilus, or anaerobes are suspected*
What are temperature requirements for bacterial specimen transport?
separate ~ from clot and refrigerate for few days; freeze if longer
What are temperature requirements for serum specimen transport?
Temperature -Routine -- room temp. or refrigerate -Special -- *do NOT refrigerate if Neisseria, Haemophilus, or anaerobes are suspected* -Freeze most viruses (for shipment) *(do NOT freeze if Rabies, RSV, or Parainfluenza viruses are suspected)* (Freeze-thaw cycle is detrimental to many viruses) Serum -- separate serum from clot and refrigerate for few days; freeze if longer
What are temperature requirements for specimen transport?
Freeze most viruses (for shipment) *(do NOT freeze if Rabies, RSV, or Parainfluenza viruses are suspected)* (Freeze-thaw cycle is detrimental to many viruses)
What are temperature requirements for viral specimen transport?
Excessive saliva contamination is unacceptable. Acceptability Standard: *More than 25 neutrophils and less than 10 squamous epithelial cells per 10X obj. field*
What are the acceptability standards for sputum specimens?
Multicellular organisms, elongated and bilaterally symmetric Larger than protozoan parasites (<1mm to 1m or larger) Tegument- protective covering or cuticle Smooth, ridged, spines or tubercles Attachment structures: Hooks, suckers, teeth, or plates Useful in identification Primitive nervous and excretory systems Alimentary canal in some No circulatory system
What are the characteristics of Helminths?
Common name: Small intestinal fluke Pathogenesis: Intestinal upset Treatment: Praziquantel, niclosamide Geographical distribution: Far East, Israel, Russia and Spain **Can't distinguish these species by eggs alone**
What are the characteristics of Metagonimus yokogawai/Heterophyes heterophyes?
Intermediate host: Fresh water snail (Bulinus) Infective form: Cercaria Mode of infection: Active penetration Identification form: Ova Size: 170 x 60μm (large) Shape: Elongated Color: Hyaline Content: Miracidium Spine: Conspicuous, terminal
What are the characteristics of Schistosoma haematobium?
Size: 155 x 60μm (large) Shape: Elongated Color: Light brown Content: Miracidium Spine: Conspicuous, lateral
What are the characteristics of Schistosoma mansoni ova?
Pathogenesis: Schistosomiasis also known as bilharzia (bilharziasis) or snail fever Often termed Blood Flukes Factors affecting pathogenesis: Varies with species -Number of ova produced -Reinfection -Nutritional state of host
What are the characteristics of Schistosoma species?****
Localized cutaneous lesions Allergenic reactions Toxic reactions: Eosinophilia Abdominal edema and ascites Intestinal ulceration and necrosis
What are the characteristics of Schistosomiasis cercarial penetration?
*Cysticercosis* -infection of both humans and pigs with larval stages of Taenia solium Humans are infected either by *ingestion of food contaminated with feces, or by AUTOINFECTION*. In the latter case, a human infected with adult T. solium can ingest eggs produced by that tapeworm, either through fecal contamination or, possibly, from proglottids carried into the stomach by reverse peristalsis.
What are the characteristics of the Taenia solium life cycle?
Male: Flattened and rolled to form a gynecophoral groove; resembles a taco shell Female: Slender and cylindrical, fits in the groove of the male Color: Tan to gray Testes: Number characteristic of species Rejoined ceca: Length of reunited stem varies with species
What are the characteristics of the adult Schistosomes?
*Single sample test* (antigen or early antibody): (e.g. handheld assay) collect & test *immediately* Comparison test (Ab quantity increase) -*Acute phase -- w/in 7 days after onset* -*Convalescent phase -- @ 14-21 days after onset*
What are the characteristics of virus immunodiagnostics specimen timing?
Decontaminate the groin area of the infant Attach the bag with self-adhesive Remove the bag as soon as urine has been collected -- handle as clean-catch specimen If no urine has been collected within 30 minutes, recleanse the area and attach a fresh bag
What are the collection guidelines for urine collected in a sterile, plastic collection bag (pediatric)?
Cleanse the periurethral area to reduce contamination During the flow of urine, collect several milliliters of urine in a sterile container Female - after cleansing urethral orifice while holding labia apart; collect flowing urine after rinsing the urethra Male - after cleansing the glans penis, collect flowing urine after rinsing the urethra Transport -- deliver to the lab within one hour or refrigerate up to 8-12 hours
What are the collection techniques for Midstream Clean-catch method of urine specimens?
10 % Formalin Polyvinyl Alcohol (PVA) Merthiolate-Iodine-Formalin (MIF) Sodium Acetate Formalin (SAF)
What are the fecal preservatives?
Cervical exudate and/or mucous -Prevent contamination by normal flora -Do not use lubricant on speculum
What are the female exudates for N. gonorrhea and Chlamydia?
1. Adult 2. Larva 3. Egg/Ova 4. Trophozoite 5. Cysts
What are the forms of parasites?
Intermediate host: Fresh water snail (Biomphalaria) Reservoir host: Primates, insectivores, wild rodents Infective form: Cercaria Mode of infection: Active penetration
What are the host and infective form of Schistosoma mansoni?
Procercoid and cercoid
What are the infective forms of Spirometra species?
crustacean and freshwater fish
What are the intermediate hosts of Diphyllobothrium latum?
Pigs are (completion of the life cycle occurs in regions where humans live in close contact with pigs and eat undercooked pork.)
What are the intermediate hosts of Taenia solium?
Miracidium -All Trematodes -Hatches in water -Ciliated Sporocyst: One or more generations Redia: One or more generations Cercaria -Form which completes development in the snail and then leaves -Free swimming -Infective form to man: For dioecious organisms (Schistosomes don't form metacercaria form) Metacercaria -Encysted cercaria -Infective form to man: For monoecious organisms
What are the larval stages of Class Trematoda?
S. mansoni - most prominent (lateral spine on egg; found in ~feces) S. japonicum (vestigial spine/hard to see; ~found in feces) S. haematobium (terminal spine; ~found in urine)
What are the main species of Schistosoma?
Urethral exudate -"Milk" the urethra if necessary -Insert swab into urethra if needed
What are the male exudates for N. gonorrhea and Chlamydia?
1. Blood- For Plasmodium sp. (Thick and thin smears) 2. Sputum; pleural effusions, etc.: For parasites in the lungs 3. Urethral and vaginal exudates: For parasites of the urogenital tract 4. Urine sediment: For parasites of the urogenital tract 5. CSF 6. Skin scrapings 7. Biopsy 8. Serum 9. Bone marrow
What are the non-fecal clinical specimens for parasite detection?
Bacteroides spp. Enterobacteriaceae: E. coli, Citrobacter, Proteus, Serratia, Enterobacter, Klebsiella, Providencia Enterococcus spp. (lower number) Low numbers of the following -Yeast -Clostridium spp. -Staphylococcus aureus -Several other possibilities
What are the normal flora of the GI tract?
None - except very temporarily after brushing teeth for example
What are the normal flora of the blood?
Male and female: -Staphylococcus spp. (S. epi.) -Corynebacterium spp. Female: -Various gram-negative bacilli -Various anaerobes -Streptococci (misc. spp.) -Lactobacillus spp. (GPB) -Yeast (Candida albicans, etc.)
What are the normal flora of the genital tract?
Staphylococcus spp. (esp. Staph. epidermidis) Corynebacterium spp. (not C. diphtheriae) Propionibacterium spp. (GPB, *anaerobe*) Candida spp. (low numbers, warm/moist areas) Dermatophytic fungi (low numbers)
What are the normal flora of the skin?
Alpha & gamma Streptococcus (GPC) Neisseria spp (GNDC) Staphylococcus spp (GPC) *other than S. aureus* Corynebacterium spp (GPB) *other than C. diphtheria* (various anaerobes)
What are the normal flora of the upper respiratory tract?
None, except skin and vaginal flora which may contaminate urine during collection
What are the normal flora of the urinary tract?
In addition to the liver and lungs, other organs (brain, bone, heart) can also be involved, with resulting symptoms. ~ multilocularis affects the liver as a slow growing, destructive tumor, with abdominal pain, biliary obstruction, and occasionally metastatic lesions into lungs and brain. ~ vogeli affects mainly the liver, where it acts as a slow growing tumor; secondary cystic development is common.
What are the organs/tissues involved in Echinococcus infections?
Trichomonas vaginalis (protozoan) Candida albicans *(non-STD)* Gardnerella vaginalis (GNB) - bacterial vaginosis
What are the other, lower frequency pathogens of the genital tract?
Streptococcus pneumoniae Mycoplasma pneumoniae Haemophilus influenzae - (adults) Moraxella catarrhalis Legionella - pneumonia Chlamydia pneumoniae Klebsiella pneumoniae Group A Streptococcus -- also lung abscess Staphylococcus aureus -- also lung abscess Mycobacterium tuberculosis
What are the predominant bacterial pathogens of pneumonia in the LRT?
None
What are the predominant normal flora of the lower respiratory tract, sinuses, middle ear?
Streptococcus pneumoniae (#1 overall) Neisseria meningitidis (esp. 4-30 yo) Haemophilus influenzae (non-vaccinated infants) ------------------------------ Enterobacteriaceae (esp. E. coli) Staphylococcus aureus Encephalitis viruses Cryptococcus neoformans
What are the predominant pathogens from CSF?
Staphylococcus aureus (24%) Coagulase-negative staphylococci (Staph epidermidis) (15%) ** Escherichia coli (11%) Enterococcus spp (9%) Yeast (8%) Streptococcus pneumoniae (7%) Bacteroides fragilis & other anaerobes (4%) ** Overall 30+% (15% were contaminants)
What are the predominant pathogens in blood culture?
Campylobacter jejuni Salmonella enteritidis Shigella spp. Clostridium difficile (Toxin - Antibiotic Associated Enterocolitis) Vibrio cholerae - Asia, S. America, C. America Yersinia enterocoliticia (GNB)
What are the predominant pathogens of the GI tract?
Chlamydia trachomatis Neisseria gonorrhoeae Herpes simplex Treponema pallidum
What are the predominant pathogens of the genital tract?
*Staphylococcus aureus* *Group A Streptococcus* --top two make up ~90% of all skin/tissue infections Escherichia coli Pseudomonas aeruginosa, Proteus, etc. -- burns, nosocomial wound infections Other GNB from soil/fecal sources -------------------------------------------------------- Clostridium spp. (anaerobe) Bacteroides spp. (anaerobe) -------------------------------------------------------- Herpes simplex Candida albicans Microsporum, Trichophyton, Epidermophyton Haemophilus, Adenovirus -- pink eye
What are the predominant pathogens of the skins, wounds, and tissue abscesses?
Escherichia coli Staphylococcus saprophyticus Enterococcus spp. Various gram-negative bacilli (enterics)
What are the predominant pathogens of the urinary tract?
Schistosoma japonicum: Feces*** Schistosoma mansoni: Feces*** Schistosoma haematobium: Urine*** FEA for feces Microscopic analysis for urine
What are the preferred specimens for diagnosing Schistosomes?
Confirm presumptive diagnosis Rule out infection Obtain information for antimicrobic therapy
What are the principles guiding your decision to submit a specimen?
Disinfect and anesthesize the skin over the bladder, and puncture directly into the bladder using a long needle & syringe *The only acceptable procedure for anaerobic culture*
What are the proper collection techniques for suprapubic aspiration of the urine from the bladder?
Disinfect & anesthetize lumbar spinal area Perform spinal tap via lumbar puncture Collect about 10 mL distributed in 3 tubes If pressure is too low to collect more than 3 mL, then leave it all in one tube Deliver to lab immediately Do NOT refrigerate
What are the proper specimen collection and handling techniques for CSF?
Collect blood before antimicrobial therapy is initiated, if possible Collect *2 or 3 samples from at least 2 body sites* [Each sample is 2 bottles] -Quantity of blood -Differentiation between pathogen & contaminant *All specimens may be collected at the same time or spread over about 2 hours*
What are the proper specimen collection guidelines for the collection and handling of blood cultures?
Label both bottles & transport to lab Routine incubation is 5 to 7 days before being reported as "negative" Negative reports will be issued at 24 hours and at end of incubation (5-7 days) Positive reports issued whenever growth appears
What are the routine handling and reports ASW blood culture once it's been submitted to the lab?
*optimal for upper respiratory viruses* Aspirate 5 mL sterile saline into rubber bulb; tip patient's head back Dispense saline into nasal area. Tip head forward and collect fluid into container Place into Viral Transport Media
What are the specimen collection guidelines for a nasopharyngeal wash?
(Everything from the uvula on up) Pass a *bent-wire swab* through a nostril to the point of resistance and gently rotate it. (Sometimes inoculate viral transport media) Once inserted let it sit for 2-5 seconds Transport w/in 2 hr
What are the specimen collection guidelines for a proper nasopharyngeal swab?
Depress tongue w/ sterile tongue blade Collect exudate or secretion on dacron swab Gently & quickly swab back of throat, tonsillar areas, & exudative areas Avoid touching tongue & mouth Place swab into transport medium & deliver w/in 2 hours
What are the specimen collection guidelines for a proper throat swab?
Collect the first deep cough production of the morning (5-10 mL) into sterile cup Collect one specimen per day for three days *Almost always collected by the patient; give adequate instructions*
What are the specimen collection guidelines for a sputum sample?
Collect formed or liquid stool in a clean cup Collect rectal swab by inserting the swab into the rectum about 2-3 cm *Do NOT collect from the toilet* Collect one specimen per day for 3 days Do NOT culture fecal specimens from patients who have been hospitalized for more than 3-4 days to Dx community-acquired gastroenteritis (flora changes) Transport w/in 2 hr; use preservatives for shipping
What are the specimen collection guidelines for stool specimens?
Collect serous fluid from cleaned lesion (maybe remove scab) Examine by ImmunoFluorescent Antibody microscopy Most syphilis testing uses Immunodiagnostic Tests (serum)
What are the specimen collection guidelines for suspected syphilitic lesion?
Collect pleural fluid by direct puncture of chest wall Transport aspirate immediately in anaerobic transporter
What are the specimen collection guidelines for thoracentesis?
Mild abdominal symptoms Most striking feature consists of the passage (active and passive) of proglottids Occasionally, appendicitis or cholangitis can result from migrating proglottids.
What are the symptoms of Taenia saginata taeniasis?
Less frequently symptomatic than Taenia saginata taeniasis. Main symptom is the passage (passive) of proglottids. *Most important feature of Taenia solium taeniasis is the risk of development of CYSTICERCOSIS*.
What are the symptoms of Taenia solium taeniasis?
Number: Taxonomically important in Schistosomes Position Para Oblique Tandem
What are the testicular arrangements in Trematoda?
(a) Age of a stool specimen: One of the most important factors affecting the diagnosis of infections (b) Liquid and diarrheic specimens: Should be examined within 30 minutes from time of passage (type of specimen where trophozoites may be found) (c) Soft specimens: Examined within one hour of passage (d) Formed specimens: Can be delayed for several hours or longer, but should be examined on the same day of submission
What are the time factors of fecal specimen collection?
Transport w/in 2 hours Special requests for mycobacteria, fungal, & viral specimens (Routine is for pneumonia)
What are the transport requirements and lab request guidelines for sputum specimens?
Cross-fertilization: Most often (when more than one adult is present) Self-fertilization: When only one organism is present
What are the two types of fertilization ASW Trematoda?
Taenia solium and ...
What are the two worms that will encyst?
Cystic ~ Alveolar ~ Polycystic ~
What are the types of human echinococcosis?
Group A Streptococcus Staphylococcus aureus
What bacterial pathogens cause lung abscess?
Taenia solium
What causes cysticercosis in humans?
About 60-75% caused by: Staphylococcus aureus Coagulase-negative Staphylococcus alpha Streptococcus
What causes endocarditis?
Haemophilus influenzae
What causes epiglottitis, otitis media in young children?
Protozoa Nematoda (roundworms Cestoda (tapeworms) Trematoda (flukes)
What classes of the 6 total parasite classes will we be focused on?
Less than 10,000 CFU/mL -- probable contamination Between 10,000 and 100,000 CFU/mL -- possible infection; possibly repeat Greater than 100,000 CFU/mL -- probable infection
What colony count numbers in a urine culture colony count indicate infection?
Proglottids Wider than long Central uterine structure resembling a "rosette"
What do the proglottids of Diphyllobothrium latum look like?
An EO-sin-ophile
What do you call a parasitologist that loves to violate EO regulations?
Size: 10 to 20 mm long by 2 to 5 mm wide Shape: Oval, elongated Color: Cream with a slight pinkish tint Intestinal ceca: Straight Testes: Dendritic and tandem
What does Clonorchis sinensis look like?
pharyngitis
What does Group A Strep cause in the URT?
Nasal folliculitis
What does Staphylococcus aureus cause in the nasal passage?
sinusitis, otitis media
What does Streptococcus p. cause in the URT?
Size: 25 to 45 mm long by 8 to 12 mm wide Shape: Leaf-like; no cephalic cone Color: Flesh-colored Intestinal ceca: Undulating Testes: Dendritic and tandem
What does the adult Fasciolopsis buski look like?
Size: 1.0 to 1.7 mm long by 0.35 mm wide Shape: Teardrop Color: Grayish Intestinal ceca: *Straight but split* Testes: Oval Medio-center acetabulum Scaly anterior region Retractile sucker like structure Armed with hooklets
What does the adult Heterophyes heterophyes look like?
Size: 0.8 to 1.4 mm long by 0.4 to 0.7 mm wide Shape: Gourd-like Color: Grayish Intestinal ceca: Straight Testes: Oval and oblique Off-center acetabulum
What does the adult Metagonimus yokogawai look like?
Lance-shaped scolex Two leaf-shaped suckers Bothria-lateral grooves that serve as organs of attachment
What does the scloex of Diphyllobothrium latum look like?
Fasciolopsis buski
What does this describe: Common name: Giant intestinal fluke Pathogenesis Intestinal upset and obstruction Toxemia and inflammation Treatment: Praziquantel, Niclosamide Geographical distribution: Southeast Asia, India ?
Paragonimus westermani
What does this describe: Habitat: Lung Intermediate host First: Snail Second: Crab or crayfish Reservoir host: Piscivores (fish-eating animals) Infective form: Metacercaria Mode of infection: Ingestion ?
Schistosoma mansoni
What does this describe? Common name: Manson's blood fluke Pathogenesis Abdominal pain, cramping, diarrhea, bloody stools Hepatosplenomegaly Geographic distribution: South and Central America, Cuba, Puerto Rico, Africa Habitat: Venules of the large intestine
Fasciola hepatica
What does this describe? Habitat: Bile passages of the liver Intermediate host First: Snail Second: Fresh water vegetation Reservoir host: Herbivores and carnivores Infective form: Metacercaria Mode of infection: Ingestion
Clonorchis sinensis
What does this describe? Habitat: Bile passages of the liver Intermediate host First: Snail (several species of fresh water snails) Second: Fish Reservoir host: Piscivores Infective form: Metacercaria Mode of infection: Ingestion
Larval form
What form of Spirometra is found in humans?
Common name: Chinese liver fluke Pathogenesis Cirrhosis: Swelling of the bile ducts Blockage of the bile passages Multiple infections: Up to 21,000 adults per host Treatment Praziquantel, Chloroquine, Bithionol Geographical distribution: Asia
What is Clonorchis sinensis?
Common name: Sheep liver fluke Pathogenesis Mechanical destruction of liver tissue Fibrosis Treatment: Bithionol or Dehydroemetine Geographical distribution: Worldwide; sheep raising countries
What is Fasciola hepatica (Trematoda)?
Habitat: Small intestines Intermediate host First: Snail Second: Aquatic vegetation Reservoir host: Pigs, dogs and rabbits Infective form: Metacercaria Mode of infection: Ingestion
What is Fasciolopsis buski?
Common name: Lung fluke Pathogenesis -Tuberculosis-like symptoms -Lung damage: Fibrosis -Migratory tissue damage -Extra pulmonary abscesses Treatment: Praziquantel, Bithionol Geographical distribution: Asia, South America, Africa and India
What is Paragonimus westermani (Trematoda)?
Common name: Oriental blood fluke Pathogenesis Most pathogenic: Produces most eggs per day Hepatic and pulmonary lesions Central nervous system involvement Geographic distribution: Far east Habitat: Venules of small intestine
What is Schistosoma japonicum?
Proglottids
What is characteristic of cestodes?
spiked, non-operculated
What is characteristic of schistosomal ova?
Incomplete digestive tract Mouth, pharynx, and esophagus Blind-sac intestines (ceca)
What is characteristic of the Trematoda digestive system?
operculated Contains first stage larva
What is characteristic of the majority of trematode ova?
Patient ID -- name, ID #, age, sex, room/clinic Clinical information - Presumptive diagnosis - Anatomic site - Antimicrobics in progress - Time & date collected *(time zero)* Exam requested - Routine vs special screening/culture/susc. - Microscopic exam desired Signature
What is included on the microbiology request form?
Scolex Four, muscular cup-shaped suckers Crown of hooklets
What is pictured here?
Scolices of Taenia saginata Four, muscular cup-shaped suckers No crown of hooklets on rostellum
What is pictured here?
Sometimes special request PCR typically available (in fixed-facility hospital) & provides good results EIA / ELISA sometimes used Gram stain of no benefit; Direct microscopic exam not very sensitive; Special stain from cell culture
What is routine lab testing for Chlamydia?
Gram stain meaningful primarily for males *Females have normal GNC flora (may present interpretation challenge)* PCR typically available (in fixed-facility hospital) & provides good results Frequently culture female cervix (and often anus and throat) Sometimes culture males; especially for confirmation and proof of cure
What is routine lab testing for gonorrhea?
Echinococcus larval form in humans which is a slow-growing, tumor-like, and space occupying structure with a membrane (unilocular)
What is the Hydatid cyst?
The immune response (antibody detection in serum)
What is the best method for detecting Taenia?
Coracidium
What is the ciliated, free-swimming larval form of Diphyllobothrium latum?
can be a long-lasting infection (decades). Most infections are asymptomatic. Manifestations may include abdominal discomfort, diarrhea, vomiting, and weight loss. Vitamin B12 deficiency with pernicious anemia may occur. Massive infections may result in intestinal obstruction. Migration of proglottids can cause cholecystitis or cholangitis.
What is the clinical manifestation of Diphyllobothriasis?
granulosus infections remain silent for years (5-20) before the enlarging cysts cause symptoms in affected organs. Hepatic involvement can result in abdominal pain, a mass in hepatic area, and biliary duct obstruction. Pulmonary involvement can produce chest pain, cough, and hemoptysis. Rupture of cysts can produce fever, urticaria, eosinophilia, and anaphylactic shock, as well as cyst dissemination.
What is the clinical presentation of Echinococcus?
Hymenolepis nana and H. diminuta infections are most often asymptomatic. Heavy infections with H. nana can cause weakness headaches, anorexia, abdominal pain, and diarrhea.
What is the clinical presentation of Hymenolepsis?
Dogs are where the adult forms are found (dogs ingest cysts when consuming sheep flesh)
What is the definitive host for Echinococcus?
Embryonated egg
What is the diagnostic form of Paragonimus westermani?
worldwide
What is the distribution of Taenia solium?
After treatment, stools should be collected for 3 days to search for tapeworm proglottids for species identication. Stools should be re-examined for Taenia eggs 1 and 3 months after treatment to be sure the infection is cleared.
What is the follow up to treatment with Praziquantel for active taeniasis?
Cercaria
What is the infective form for Schistosomiasis?
metacercaria
What is the infective form of Clonorchis sinensis?
Plerocercoid/Sparganum
What is the infective form of Diphyllobothrium latum?
metacercariae Mammals acquire the infection by eating vegetation containing metacercariae.
What is the infective form of Fasciola hepatica?
Metacercaria
What is the infective form of Paragonimus westermani?
Sheep - tissues are infected by cysts
What is the intermediate host for Echinococcus?
*On the likelihood* that specific organisms cause specific diseases. Therefore, lab inoculates specific culture media or performs certain tests based on the specimen source (adjusted based on information about low likelihood pathogen)
What is the lab work-up based on?
Embryonated eggs are discharged in the biliary ducts and in the stool (1). Eggs are ingested by a suitable snail intermediate host (2) . Each egg releases a miracidia (2a), which go through several developmental stages (sporocysts (2b) , rediae (2c), and cercariae (2d)). The cercariae are released from the snail and after a short period of free-swimming time in water, they come in contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae (3). Infection of humans occurs by ingestion of undercooked, salted, pickled, or smoked freshwater fish (4) . After ingestion, the metacercariae excyst in the duodenum (5) and ascend the biliary tract through the ampulla of Vater (6). Maturation takes approximately 1 month. The adult flukes (measuring 10 to 25 mm by 3 to 5 mm) reside in small and medium sized biliary ducts. In addition to humans, carnivorous animals can serve as reservoir hosts
What is the life cycle of Clonorchis sinensis?
Immature Fasciola eggs are discharged in the biliary ducts and in the stool (1) . Eggs become embryonated in water (2) , eggs release miracidia (3) , which invade a suitable snail intermediate host (4), including the genera Galba, Fossaria and Pseudosuccinea. In the snail the parasites undergo several developmental stages (sporocysts (4a) , rediae (4b), and cercariae (4c)). The cercariae are released from the snail (5) and encyst as metacercariae on aquatic vegetation or other surfaces. Mammals acquire the infection by eating vegetation containing metacercariae. Humans can become infected by ingesting metacercariae-containing freshwater plants, especially watercress (6). After ingestion, the metacercariae excyst in the duodenum (7) and migrate through the intestinal wall, the peritoneal cavity, and the liver parenchyma into the biliary ducts, where they develop into adult flukes (8). In humans, maturation from metacercariae into adult flukes takes approximately 3 to 4 months. The adult flukes (Fasciola hepatica: up to 30 mm by 13 mm; F. gigantica: up to 75 mm) reside in the large biliary ducts of the mammalian host. Fasciola hepatica infect various animal species, mostly herbivores (plant-eating animals).
What is the life cycle of Fasciola hepatica?
Immature eggs are discharged into the intestine and stool (1). Eggs become embryonated in water (2) , eggs release miracidia (3), which invade a suitable snail intermediate host (4). In the snail the parasites undergo several developmental stages (sporocysts (4a), rediae (4b) , and cercariae (4c)). The cercariae are released from the snail (5) and encyst as metacercariae on aquatic plants (6). The mammalian hosts become infected by ingesting metacercariae on the aquatic plants. After ingestion, the metacercariae excyst in the duodenum (7) and attach to the intestinal wall. There they develop into adult flukes (20 to 75 mm by 8 to 20 mm) in approximately 3 months, attached to the intestinal wall of the mammalian hosts (humans and pigs) (8). The adults have a life span of about one year
What is the life cycle of Fasciolopsis buski (Trematoda)?
Eggs in human feces Egg ingested by insect Humans and rodents infected when ingesting arthropods (Humans can also directly ingest eggs from feces contaminated foods/water) Oncosphere hatches and reaches adulthood in human
What is the life cycle of Hymenolepsis nana?
Adults release embryonated eggs each with a fully-developed miracidium, and eggs are passed in the host's feces (1). After ingestion by a suitable snail (first intermediate host), the eggs hatch and release miracidia which penetrate the snail's intestine (2). Genera Cerithidia and Pironella are important snail hosts in Asia and the Middle East respectively. The miracidia undergo several developmental stages in the snail, i.e. sporocysts (2a), rediae (2b), and cercariae (2c). Many cercariae are produced from each redia. The cercariae are released from the snail (3) and encyst as metacercariae in the tissues of a suitable fresh/brackish water fish (second intermediate host) (4). The definitive host becomes infected by ingesting undercooked or salted fish containing metacercariae (5). After ingestion, the metacercariae excyst, attach to the mucosa of the small intestine (6) and mature into adults (measuring 1.0 to 1.7 mm by 0.3 to 0.4 mm) (7). In addition to humans, various fish-eating mammals (e.g., cats and dogs) and birds can be infected by Heterophyes heterophyes or Metagonimus yokogawai. The main symptoms are diarrhea and colicky abdominal pain. Migration of the eggs to the heart, resulting in potentially fatal myocardial and valvular damage, has been reported from the Philippines. Migration to other organs (e.g., brain) has also been reported.
What is the life cycle of Metagonimus yokogawai/Heterophyes heterophyes?
The eggs are excreted unembryonated in the sputum, or alternately they are swallowed and passed with stool (1). In the external environment, the eggs become embryonated (2) , and miracidia hatch and seek the first intermediate host, a snail, and penetrate its soft tissues (3). Miracidia go through several developmental stages inside the snail (4) : sporocysts (4a), rediae (4b), with the latter giving rise to many cercariae (4c), which emerge from the snail. The cercariae invade the second intermediate host, a crustacean such as a crab or crayfish, where they encyst and become metacercariae. This is the infective stage for the mammalian host (5) . Human infection with P. westermani occurs by eating inadequately cooked or pickled crab or crayfish that harbor metacercariae of the parasite (6). The metacercariae excyst in the duodenum (7) , penetrate through the intestinal wall into the peritoneal cavity, then through the abdominal wall and diaphragm into the lungs, where they become encapsulated and develop into adults (8) (7.5 to 12 mm by 4 to 6 mm). The worms can also reach other organs and tissues, such as the brain and striated muscles, respectively. However, when this takes place completion of the life cycles is not achieved, because the eggs laid cannot exit these sites. Time from infection to oviposition is 65 to 90 days. Infections may persist for 20 years in humans. Animals such as pigs, dogs, and a variety of feline species can also harbor P. westermani.
What is the life cycle of Paragonimus westermani?
Eggs are eliminated with feces or urine (1). Under optimal conditions the eggs hatch and release miracidia (2), which swim and penetrate specific snail intermediate hosts (3) . The stages in the snail include 2 generations of sporocysts (4) and the production of cercariae (5) . Upon release from the snail, the infective cercariae swim, penetrate the skin of the human host (6), and shed their forked tail, becoming schistosomulae (7). The schistosomulae migrate through several tissues and stages to their residence in the veins (8,9). Adult worms in humans reside in the mesenteric venules in various locations, which at times seem to be specific for each species (10). For instance, S. japonicum is more frequently found in the superior mesenteric veins draining the small intestine (A) , and S. mansoni occurs more often in the superior mesenteric veins draining the large intestine (B). However, both species can occupy either location, and they are capable of moving between sites, so it is not possible to state unequivocally that one species only occurs in one location. S. haematobium most often occurs in the venous plexus of bladder (C) , but it can also be found in the rectal venules. The females (size 7 to 20 mm; males slightly smaller) deposit eggs in the small venules of the portal and perivesical systems. The eggs are moved progressively toward the lumen of the intestine (S. mansoni and S. japonicum) and of the bladder and ureters (S. haematobium), and are eliminated with feces or urine, respectively (1). Pathology of S. mansoni and S. japonicum schistosomiasis includes: Katayama fever, hepatic perisinusoidal egg granulomas, Symmers' pipe stem periportal fibrosis, portal hypertension, and occasional embolic egg granulomas in brain or spinal cord. Pathology of S. haematobium schistosomiasis includes: hematuria, scarring, calcification, squamous cell carcinoma, and occasional embolic egg granulomas in brain or spinal cord. Human contact with water is thus necessary for infection by schistosomes. Various animals, such as dogs, cats, rodents, pigs, horse and goats, serve as reservoirs for S. japonicum, and dogs for S. mekongi.
What is the life cycle of Schistosomes?
Habitat: Small intestines Intermediate host First: Snail Second: Fish Reservoir host: Piscivores and birds Infective form: Metacercaria Mode of infection: Ingestion
What is the life cycle summary of Metagonimus yokogawai/Heterophyes heterophyes?
The tegument of the worm causes an outsized host immune reaction
What is the majority of pathology in relation to parasitic worms caused by?
The body is flattened dorso-ventrally; leaf-shaped Monozoic: One body part Suckers: Two Oral sucker: Mouth Ventral sucker -Acetabulum; hold-fast organ
What is the morphology of Flukes?
The dog Other potential hosts include cats, foxes, and humans (mostly children) (6), (7).
What is the principal definitive host for Dipylidium caninum?
Decontaminate the surface to kill normal flora contaminants Aspirate the exudate using needle and syringe If anaerobe is suspected, transport immediately in anaerobic transporter
What is the proper collection and handling for a deep abscess, wound, and lesion (possible anaerobe)?
Collect exudate Transport & process w/in 2 hr Use transport media *depending on lesion, collect from periphery of infection site*
What is the proper collection and handling of a skin swab (non-aerobic lesion)?
Disinfect skin w/ 70% alcohol Scrape the periphery of lesion with sterile scapel Collect scrapings or nail clippings in petri dish, clean envelope, or glass slide Pluck suspected hairs w/ forceps or knife blade KOH or other wet mount exam
What is the proper collection and handling procedure for a skin scraping for fungi?
Straight Undulating Branched Rejoined
What is the shape of Trematoda intestinal ceca?
Oval Lobate Dendritic or branched
What is the shape of Trematode balls?
The same bacteria may be both normal flora and the pathogen -Normal flora -- low numbers -Pathogen -- high numbers
What is the significance colony counts in a Urine culture colony count?
Size: 20 to 30 mm long by 8 to 13 mm wide Shape: Leaf-like; prominent cephalic cone Color: Brownish Intestinal ceca: Branched Testes: Dendritic and tandem
What is the specimen of choice for identifying Fasciola hepaticum adults?
Feces - FEA Identification form: Ova Size: 140 x 80μm Shape: Hen's egg; oval Color: Light yellowish brown Operculum: Present, indistinct Content: Yolk mass; fills the egg
What is the specimen of choice for identifying Fasciola hepaticum ova?
Specimen of choice is feces: FEA Identification form: Ova Size: Similar to Clonorchis sinensis No abopercular process
What is the specimen of choice for identifying Metagonimus yokogawai/Heterophyes heterophyes?
Feces - FEA Identification form: Ova; almost identical to Fasciola hepatica except that the granules in the yolk mass are uniformly distributed
What is the specimen of choice to identify Fasciolopsis buski?
immediately
What is the specimen transport time for CSF lab testing?
immediately if not in anaerobic transporter; otherwise w/in 2 hours
What is the specimen transport time for anaerobes lab testing?
(serum) w/in 2 hours
What is the specimen transport time for blood for immunologic lab testing?
w/in 2 hours
What is the specimen transport time for routine lab testing?
immediately (gonorrhea culture)
What is the specimen transport time for urethral exudate lab testing?
w/in 1 hour or refrigerate
What is the specimen transport time for urine lab testing?
immediately (lab may freeze and ship)
What is the specimen transport time for virus culture lab testing?
Taxonomically important in Schistosomes Described as smooth, finely tuberculated, or grossly tuberculated
What is the tegument like in Trematoda?
Schistosomulae
What life cycle stage of Schistosomes enters the blood on its way to the liver?
Schistosoma haematobium
What parasite does this describe? Common name: Vesical blood fluke Pathogenesis Urogenital tract involvement Liver Geographic distribution: Africa, Asia Minor Habitat: Venules of urinary bladder surrounding organs are affected
Schistosoma japonicum
What parasite does this describe? Intermediate host: Fresh water snail (Oncomelania) Reservoir host: Mammals exposed to contaminated water Infective form: Cercaria Mode of infection: Active penetration
10
What percent of blood cultures are positive?
Occult blood
What stool tests for blood you can't see?
Intradermal test Ova hatching test Indirect hemagglutination Indirect fluorescent antibody Rectal biopsy ELISA tests
What tests are used to identify Schistosomes?
Monoecious
What type of reproductive system do most Trematodes have?
Taeniasis
When Taenia worm stays in your gut it is called?
Infants - need to get past the anus and into the rectum (don't perforate rectum)
When would you use a rectal swab for stool specimen collection?
*Lung tissue Induced sputum Stool*
Where can you see the eggs of Paragonimus westermani?*****
tiny crustaceans (Cyclops and Diaptomus species)
Where do the Copepod stage Diphyllobothrium latum live?
Echinococcus granulosus occurs practically worldwide, and more frequently in rural, grazing areas where dogs ingest organs from infected animals. Echinococcus multilocularis occurs in the northern hemisphere, including central Europe and the northern parts of Europe, Asia, and North America. Echinococcus vogeli and Echinococcus oligarthrus occur in Central and South America
Where does Echinococcus occur?
In dog feces
Where is the infective form of Echinococcus found?
Schistosomes
Which trematodes are dioecious?
physician PA nurse occasionally lab tech *more convenient and accurate collection for person identifying possible infection site to be the specimen collector*
Who collects a specimen?
i. Prevention of vectors from feeding on humans ii. Destruction of arthropods: Insecticides iii. Application of molluscacides iv. Genetic control of vectors
e) Elimination of intermediate host(s) or vectors
