Micro Exam 4 chaos
Group A Streptococcus
Also known as streptococcus pyogenes Among most common human pathogens Gram positive Grows in chains Facultative anaerobe Beta-hemolysis = (complete lysis (breakdown) of RBCs) Can cause: scarlet fever, pharyngitis (sore throat), erysipelas (skin infection), impetigo, and rheumatic fever, and necrotizing fasciitis Severity of infections caused by GAS ranges from minor to deadly diseases Over 80 immunological types in this group pathogens Based off antigenic properties of M proteins on cell walls
Furious (classic) rabies
Animals are restless at first, but then become highly excitable and snap at anything within reach The biting behavior is essential to maintaining the virus in the animal population Humans also exhibit similar symptoms of rabies, even biting others When paralysis sets in, the flow of saliva increases as swallowing becomes difficult, and nervous control is progressively lost The disease is fatal within days
How does amino acid availability impact existence for Group A Streptococcus
Auxotrophic for about 15 amino acids Starvation mode triggers the release of a cascade of factors Alters the rates of transcription, bacterial replication, and protein translation leads to the altered expression of virulence, differentiation, and persistence
complications of varcicella
Bacterial infections Dehydration Pneumonia Inflammation of the brain (encephalitis) Toxic shock syndrome Reye's syndrome Shingles
Bioterrorism
Biological agents for a weapon in order to perform an act of terrorism Small pox is considered the biggest fear of a bioterrorism attack Can be used to take out specific individuals or mass casualties Government put a smallpox defense team in place after 9/11 attacks
Immune response to smallpox
Body tries to use the complement system to get rid of the virus but variola virus has enzymes (SPICE) that cleaves certain portions of the complement system making it ineffective. Creates an "environment" around the variola infected cells that are protected from complement system attack, and become viral replication factories Body has limited immune response to this virus because the body needs the complement system to initiate an attack. Without the complement system the body has no attack system to rid itself of the virus... This is what makes the virus so dangerous, rapid, and hard to control.
How infection changes virulence?
Catabolite control protein A (ΔccpA) Influences the transcription levels of many carbohydrate utilization genes and several well characterized GAS virulence factors Cytolysin streptolysin S Hemolysis 10-fold difference in (ΔccpA) between a nutrient dense area (Todd-Hewitt w/ yeast) and nutrient poor (saliva)
Gas Gangrene cause
Caused by anaerobic bacteria Clostridium perfringens
Smallpox metabolism diagram
Cells that are infected with the variola virus produce a protein that blocks a wide range of human interferons, which are molecules that are produced by our immune system meant to stop viral infection Therefore, the reason smallpox is so deadly Inhibits the complement system from occurring Inhibits cytokines from altering the immune system to attack or indicate a response against the virus So the immune system is never able to recognize there is a virus in the body, it also replicates so fast that the body would never be able to kill the virus This is one of the few viruses that doesn't need a nucleus to replicate once inside a cell - uses the cytoplasm Variola uses the cytoplasm of the host cell Smallpox is entered through the oral cavity because the variola virus is attracted to mucous droplets This results in the blisters in the mouth, tongue, and throat: once these burst, they release more viruses The virus then goes into the bloodstream: affecting bone marrow, lymph nodes, and skin
What causes botulism?
Clostridium botulinum
What is Gas Gangrene
Clostridium perfringens Gram positive Bacillus Capsulated Endospore-forming Non-motile Anaerobe
Possibility of smallpox outbreak
Currently, there are only 2 places in the world that have frozen vials of the variola virus: CDC in Atlanta, Georgia and VECTOR Institute is Koltsovo, Russia Vaccination for smallpox is no longer given because it is considered eradicated Being that it spread by droplets, and skin to skin contact, and can survive on a nonliving reservoir, it is highly contractible Given all these factors, and the fact that there are still vials of this virus, the potential for smallpox to be used as a bioterrorism agent is alarming.
how does rabies attack cells?
Dr. Willoughby, a pediatric infectious disease specialist, determined that Rabies neither kills by "destroying neurons or causing inflammation in the brain," but instead, causes excitotoxicity, which overstimulates the brain and causes the cells to die
Necrotizing Fasciitis symptoms
Early symptoms are very similar to and mistaken as the flu Symptoms of Necrotizing Fasciitis Include: High Fever Infected area becomes bright red, and warm to the touch Pain which is constant and piercing Late symptoms: ulcers, color change in skin, blisters, nausea, dizziness, diarrhea, malaise, sudden lack of sensation due to nerve tissue death
botulism protection
Endospores protect the bacteria with its capsule • Produces botulinum toxin when conditions are suitable • Saliva in mucous membranes • Lysozyme breaks down cell wall of gram + bacteria
Botulism route of entry
Enters through mucous membranes and parenteral route
Changes in Group A Streptococcus in response to energy availability
Enviromental factors stimulate production of covR CovR is a protein that further increases the production of virlulence factors
How does Group A Streptococcus survive?
Facultative Anaerobe Relies almost exclusively on lactic acid fermentation. Primarily metabolizes glucose If scarce - Maltodextrins, lactose, mannose, galactose, fructose "salvage pathway"
other rabies symptoms
Fever Headache Nausea Vomiting Agitation Anxiety Confusion Hyperactivity Difficulty swallowing Excessive salivation Partial paralysis Insomnia Hallucinations Hydrophobia-due to difficulty swallowing
Gas Gangrene Resovoirs
GI tract, soil, sewage
Clostridium Botulinum
Gram-positive • Bacillus • Anaerobic • 0.3- 2.0 micrometers by 1.5-20.0 micrometers in length • Affects nervous system, skin, eyes
rabies cases in humans
Human rabies cases in the United States are rare, with only 1 to 3 cases reported annually. Twenty-three cases of human rabies have been reported in the United States in the past decade (2008-2017). Eight of these were contracted outside of the U.S. and its territories. In the US, most human cases are caused by bats. Worldwide, most human cases are caused by dog bites.
Varcicella reservoir
Humans
Rabies transmission
Humans are usually infected with the rabies virus by saliva from the bite of an infected animal - usually dogs On rare occasions, the virus can be transmitted through fresh skin abrasions and may cross mucous membranes of the nose, mouth, and even eyes The virus proliferates in the PNS and moves, fatally, toward the CNS
Rabies vaccine
Inactivated vaccine: dead rabies cells are injected into the muscle Used to prevent rabies and for a period after exposure Given by injection into skin or muscle Booster needed every six months to two years for those with high risk to exposure (veterinarians, animal control, wildlife officers, etc.) Vaccination after exposure, PEP, is highly successful in preventing the disease if administered promptly, in general within 6 days of infection Rabies vaccine should be given on days 1, 3, 7, and 14 after the first vaccination At the time of the first rabies shot they should be given another shot called Rabies Immune Globulin If person has been previously vaccinated, they will only need to get 2 doses of the rabies vaccine, one right away and another on the 3rd day Casual contact or non-infectious fluid or tissue does not constitute an exposure & does not require postexposure prophylaxis
Varcicella life cycle
Infects host when it reaches mucosal epithelial site of entry Local replication Cutaneous sites Latency
Eradication of smallpox
Last documented case of smallpox in the U.S. was in 1949 But, the rest of the world still was threatened by smallpox. WHO launched an intensive eradication plan in 1967 that involved international vaccination efforts The last natural case of smallpox reported was in Somalia in 1977 By1980, WHO declared smallpox officially eradicated and suggested cessation of vaccination 6 years after eradication, WHO first suggested that all stocks of smallpox virus be destroyed The U.S. and Russia proposed to sequence the virus and so the decision was postponed until 1993 In 1994, a committee on Orthopox Virus Infections met with WHO and unanimously agreed that the cost to humanity due to inadvertent outbreaks or biological warfare far outweighed the benefits to researchers. But yet, the deadline was postponed. Then again in 1995, and the again in 1999 with a decision to be made "no later than 2002" January 2002 came, and it was endorsed that no new destruction date be set...
Where is pork tapeworm most common?
Latin America, Asia, and Africa are most popular The incidence of cysticercosis has increased in the U.S. due to increase in immigration Pigs roam freely in these countries, leading to the spread of infection Developing countries often do not have clean water or correctly processed food They also cannot afford toilets that flush and do not have nice trash deposits that we have in the U.S. Poor hygiene attributes to spread of infection
Rabies
Latin for rage or madness Disease that almost always results in fatal encephalitis Encephalitis - inflammation of the brain Causative agents is the rabies virus, a member of the genus Lyssavirus having a characteristic bullet shape Lyssavirus are single-stranded RNA viruses with no proofreading capability, and mutant strains develop rapidly
Varcicella virus
Lipid envelope Double stranded DNA Alpha herpesvirus Cocci Transmission: person to person or contaminated air particles 150-200 nanometers
Virulence of Group A Streptococcus
M proteins: prevent activation of complement system, phagocytosis, and kill neutrophils Exotoxin A: produced by M protein- acts as super antigen (immune system contributes to damage) Hyaluronic Acid: Resembles human connective tissue, few antibodies against it Digest host cells' connective tissue Hyaluronic acid holds CT cells together Streptokinase: enzyme that dissolves blood clots Streptolysins: cytotoxic to RBCs, tissue cells, leukocytes
Pork tapeworm microbe
Microbe itself is called Taenia Solium - is classified as a parasite Class cestoidea, order cyclophyllidea, and family taeniidae The adult worm can grow to approximately 2-4m It consists of a scolex (head) which allows it to attach to the host using 4 large suckers and a row of hooks The eggs of T. Solium, is what causes damage to the human brain
Interventions / control against necrotizing fasciitis
Necrotizing facilities can spread 2 inches every 20 min Sharpie perimeter around the cellulitis to test to see if it is NF Infection seems to spread faster in fatty tissue Hyperbaric chamber Powerful IV antibiotics Surgery Skin graphs Amputation
dangers of foodborne botulism
Occurs from eating foods contaminated with the toxin • C. botulinum grows and produces toxins in food prior to consumption • Toxins are produced in low oxygen content with certain combinations of storage temperatures and preservative parameters: low acid, low sugar, low salt • Sources include improperly canned foods such as: green beans, spinach, mushrooms, beets, fish, meat products
treatment for rabies
Once symptoms appear, there is very little effective treatments, and only a handful of survivors have been reported Most of these survivors had received PEP (postexposure prophylaxis) before the appearance of symptoms The primary treatment, which succeeds in a minority of cases, is to induce an extended coma to minimize excitability while administering antiviral drugs Called the Milwaukee protocol, because this procedure was first used in WI when a girl was bitten by a rabid bat
smallpox contraction
Only affects humans Spread by face to face contact Transmitted by sneezing coughing, or even talking (droplet transmission) Can also be spread through skin contact with lesions or scabs (exudate) Variola can spread through clothing and bedding of an infected person as well.
fun facts about the rabies vaccine
Only documented case of rabies from human-to-human transmission occurred was through recipients of transplants of the corneas & three other solid organ transplants Some zoos may vaccinate animals for rabies, but this is only done to protect the animals from rabies. A typical vaccination series with the rabies immunoglobulin can cost anywhere from $2,000 to $7,000+ per person.
How pork tapeworm impacts the brain
Parasitic larvae in the parenchyma of the brain develop into viable cysts - responsible for brain damage Cysts start out as round vesicles of parasitic membrane Filled with a clear fluid containing the tapeworm head After the host attacks the cyst, it degenerates It then shrinks and is replaced by hyaline and fibrotic tissue - forming a calcified scar Parasites within the subarachnoid space of the brain can grow and infiltrate They then become mass-occupying lesions and block the circulation of the cerebrospinal fluid which can cause hydrocephalus
Pork tapeworm reservoirs
Pigs or humans
Pork tapeworm lifecycle
Pigs or humans (reservoirs) acquire the infection by eating the eggs in contaminated food •After being ingested the eggs hatch in the intestines and tapeworm embryos are released which penetrate the intestinal wall •The tapeworm travels through the bloodstream to other parts of the body •If the eggs travel to the brain they can cause neurocysticercosis
Rabies BIG signs and symptoms
Preliminary symptoms are mild and varied, resembling several common infections When the CNS becomes involved, the patient tends to alternate between periods of agitation and intervals of calm Frequent spasms of the muscles of the mouth and pharynx that occur when the patient feels air drafts or drinks liquids The sight or thought of water can set of spasms (hydrophobia) The final stage of the disease can result from extensive damage to the nerve cells of the brain and spinal cord
Gas Gangrene symptoms
Produces gas bubbles which cause localized swelling and loss of blood flow to bodily tissues Causes severe pain, fever, and skin will crackle like bubble wrap when compressed
rabies cases in animals
Rabies in domestic animals (dogs and cats) is uncommon in the US because of high vaccination rates (herd immunity). In the US, raccoons, skunks, and bats are the animals most likely to be infected with rabies.
How does botulism use the host to survive?
Replicates by binary fission • Amino acid fermentation • Under the right conditions, clostridium botulinum produces spores in food • No oxygen, low acid, low sugar, low salt
What is Smallpox?
Small pox is an infectious disease that is caused by the variola virus. Was an epidemic in the 1700's and 1800's. With scattered cases until 1980. Insufficient information to determine anerobic or aerobic There are two strains: variola major (more severe symptoms and higher mortality rate) and variola minor (less severe symptoms with a lower mortality rate) Nicknamed 'smallpox' to differentiate it from the bubonic plague ( 'great pox')
why do changes in virulence occur to Group A Streptococcus
Some virulence factors are digestive enzymes Break down surrounding tissues to use in metabolic processes
Rabies incubation period
The incubation period is usually long enough to allow immunity to develop from postexposure vaccination It travels, at a rate of 15-100 mm per day, along peripheral nerves to the CNS Average incubation period is 30-50 days, but has been as long as 6 years in some reported cases
How does botulism toxin work?
The toxin restricts contraction of the muscles • This happens by preventing the release of acetylcholine, a chemical messenger from the nerves, that would normally innervate the facial muscles at neuromuscular junctions. • In Botox, the toxin is administered in extremely smalldoses to paralyze the muscles below them. • With restricted contraction of the muscles, the wrinkles begin to fade.
Varcicella Vaccination
The vaccine is very important because of the fact that varicella is highly contagious -Varicella Virus Vaccine Live - a live virus given through a shot that gives the body a primary exposure. The vaccine contains a weakened Varicella zoster virus that works with the immune system. -Two doses are most effective -the first dose at 12-15 months -second dose at 4-6 years
paralytic (dumb) rabies
There is minimal excitability from the infected animal This form of rabies is common in cats The animal remains relatively quiet and may be unaware of its surroundings, but it might snap irritably if handled A similar manifestation of rabies occurs in humans, which is often misdiagnosed at Guillain-Barre Syndrome (a form of paralysis that is usually transient but sometimes fatal) or other neurological conditions
Gas Gangrene treatment
Treatment must begin immediately if gas gangrene is suspected Treatment options: Surgically remove dead tissue Heavy antibiotic dosage of penicillin and clindamycin High-pressure oxygen chamber
How does C Perfringens survive?
Type A strains of C. perfringens produce the toxins responsible for gas gangrene. One of the toxins communicates to the host cell to call the white blood cells to the blood vessels rather than the infection site. This inhibits white blood cells from reaching the bacterial cells, thus preventing the body from fighting off the infection. The second part of this toxin produces a pore in the host cell which causes the host to lyse. Without these toxins C. Perfringens could NOT cause gas gangrene.
Hyperbaric Oxygen Therapy (HBOT) & Antibiotics
Used in conjunction with antibiotics Type 2 is treated with antibiotics against S. pyogenes and S. aureus Over oxygenates tissues allowing new blood vessels to form Can increase the effects of antibiotics and the body's own immune system Strep A is anaerobic, it can't replicate, or release toxins while in the chamber
Gas Gangrene and drug use
User's find and use dirty (secondary) needles, which have the bacterium Clostridium Perfringens on them The bacterium is injected into the user's body along with the drug, and carries itself in bubbles of gas The bacterium finds its way to the blood stream or adheres to the muscle near the injection site The bacterium bubbles explode and can spread out into the entire body within 4-6 hours If the user does not receive medical attention within this time frame, the infection will lead to sepsis and will become fatal.
How do we identify botulism
Using samples of feces, serum, gastric fluid, wound swabs and pus (wound botulism) in a direct enzyme-linked immunosorbent assay (ELISA)
Diagnosis of rabies
Usually diagnosed in the laboratory by detection of the viral antigen using the direct fluorescent-antibody (DFA) Test This test is nearly 100% sensitive and is highly specific Tests can be done on saliva samples, blood, CSF, and skin Postmortem samples are usually taken from the brain of infected animals In less developed parts of the world, the CDC developed a rapid immunohistochemical test (RIT) It requires only the use of an ordinary light microscope and has the sensitivity and specificity equivalent to the standard DFA test The only way to truly diagnose Rabies in animals is if the animal is dead.
tips to prevent rabies infection
Vaccinate your pets, and keep their rabies vaccine up to date If you are bitten or scratched by any animal, consult your physician immediately Don't keep wild animals as pets Avoid direct contact with wildlife, either dead or alive Do not touch any wildlife with your bare hands Avoid animals displaying unnatural behavior Do not let your pets interact with wild animals Feed your pets indoors when possible Animal proof your trash cans
smallpox vaccine
Vaccination- An attenuated vaccine. Small pox is the only disease to be eradicated by vaccination. We no longer vaccinate for the disease, but a stockpile of 2.4 million doses are stored at the WHO headquarters in Switzerland. The vaccination had awful side effects which included -Difficulty breathing -Swollen Joints -Rash -Muscle Cramps -Skin Lesions -Loss of Consciousness
What is Varcicella?
Varicella zoster virus Known as a childhood disease Reactivation Highly contagious Humans Respiratory mucous membranes and skin
Variola's interaction with the immune system
Variola produces defense proteins that protect and hide it from the hosts immune system: Virokines- Proteins encoded by a virus that are secreted by the host cell and serve to deceive the hosts immune system Viroreceptors- Cellular receptors altered by a virus to mimic cellular molecules to block extracellular signals Intracellular proteins- Interfere with the host's normal signaling and enzymatic pathways
Rabies mode of transmission
Vector borne biological
Smallpox prevention
Wash your hands Wear gloves and mask around those infected. Thoroughly wash clothes and bedding after being around those exposed by small pox Isolate those who are infected
what would a smallpox outbreak mean for the world
We are not currently vaccinating for smallpox, so variola virus would spread quickly Variola major has a 30% mortality rate and had 300 million deaths alone in the 20th century. We know a smallpox outbreak would have devastating effects on the U.S. population because of a government lead smallpox bioterrorism exercise conducted in June 2001 Within 12 days of the scenario, 14,000 cases reported to the CDC from 25 states, 1,000 dead and an estimated 5,000 more deaths over 2 weeks In addition to this, smallpox is not easily diagnosed. This is especially true now that physicians have not seen any active cases of smallpox in years
Iatrogenic Botulism:
When botox treatment goes wrong A rare acquired neuromuscular junction disease with descending flaccid paralysis due to an overdose of the injected toxin.
How does pork tapeworm cause seizures
When parasite larvae develop into cysts in the parenchyma, the brain faces severe danger The parenchyma is the functional tissue of the brain composed of both neurons and glial cells Damage to these cells is irreversible if seizures occur The inflammatory response of the brain due to parasites dying within, causes electrical instability of the neurons This leads to seizures and convulsions - which is the main complication of tapeworm in the human body Cell death from seizures is irreversible and can often lead to brain damage, dysfunction, disability, and in severe cases, death
can you get rabies from eating infected meat?
Yes. Meat that is rare / medium rare still contains blood of the infected animal, meaning that the virus is within the blood Meat that is not cooked all the way through still contains the virus, because the virus has not been killed by the heat of cooking Meat that has been cooked thoroughly poses no threat to the consumer However, it is not recommended that you eat the meat of an infected animal
Necrotizing Fasciitis cause
caused by Group A Streptococcus
Foodborne botulism
commonly seen in homemade foods that are improperly canned, preserved or fermented. Occasionally seen in storebought goods, although seen less frequently
How is varcicella transmitted?
from person to person mainly via the respiratory route. Vesicular fluid from skin lesions can give off small aerosols which can then be inhaled. Can also spread via direct contact with the vesicular fluid or contact with infected respiratory tract secretions. (Contact transmission- Direct contact and droplet transmission)
Botulism reservoirs
humans and nonliving (like food)
Group A Streptococcus resovoir
humans- Commonly found in respiratory tract and skin
good uses of botulism
injected in tiny amounts and in a purified form to produce many health benefits . Temporary smoothing of facial wrinkles to improve appearance • Severe underarm sweating • Cervical dystonia- neurological disorder that causes severe neck and shoulder muscle contractions • Blepharospasm- uncontrollable blinking • Strabismus- misaligned eyes • Chronic migraine • Overactive bladder
What relation does botulism have with the host?
opportunistic pathogen
Gas Gangrene portal of entry
parenteral
Rabies portal of entry
parenteral route
Gas Gangrene type C strain
produces a different toxin responsible for Pigbel's disease
Gas Gangrene type A strain
produces the toxins present in gas gangrene
Group A Streptococcus portal of entry
through break in skin (external or internal) or mucous membranes Cut, scrape, surgical laceration Soft tissue (subcutaneous/muscle)- becomes invasive
Gas Gangrene mode of transmission
vector borne biological
Botulism mode of transmission
vehicle borne
How to prevent foodborne botulism
• Follow safe canning instructions • Sterilize canning items • Use pressure canners
How to prevent Iatrogenic botulism
• Iatrogenic Botulism • Only receive Botox treatment from a licensed practitioner
Necrotizing Fasciitis
"Flesh eating" disease Necrotizing refers to the death of tissues Fasciitis means the inflammation of the fascia, which is tissue that surrounds muscles, fat, nerves, and blood vessels The release of exotoxins by Group A streptococcus as waste products Exotoxins cause tissue ischemia by restricting blood supply to the tissue
Adult intestinal botulism
(Adult Intestinal Colonization)- very rare
Iatrogenic botulism
- seen when too much botulinum toxin is used for cosmetic or medical reasons, such as to treat wrinkles and headaches
Botulism signs and symptoms
. Facial nerve paralysis • Dry mouth and throat • Nausea and vomiting • Abdominal distension • Problem of urinating • Muscle weakness • Tachycardia • Slurred speech • Double vision
how rabies travels in the body
1. The virus is introduced into the wound in numbers too low to trigger an immune response. It enters the body through a bite, and on rare occasions, through mucous membranes 2. It multiplies in skeletal muscle and connective tissue, where it remains for long periods, ranging from days to months. 3. It enters a motor neuron along PNS and proliferates into the CNS where it causes encephalitis. Bites in areas rich in nerve fibers result in shorter incubation periods.
First stage of smallpox
2-4 Days: Prodrome Phase Implantation of virus onto respiratory mucosa. Virus beings to multiply spreading to the bone marrow, lymph nodes, and spleen High fever, headache, malaise During this time the person becomes contagious Complement system is knocked out
Varcicella signs and symptoms
3 Phases Raised red or pink bumps (papules) Small fluid-filled blisters (vesicles) Crusts and scabs
Second stage of smallpox
4 days: Early Rash The virus localizes into small blood vessels of the dermis, which causes infection of adjacent cells This is when the defense protiens are spreading Rash first appears in the mouth and pharynx and ulcerate, which release large amounts of the virus into the saliva. Soon after rashes on the skin By the end of the 4th day of the rash the bumps are usually raised and filled with fluid Extremely contagious during this time Symptoms include extreme thirst, difficulty and pain with swallowing and movement
Third stage of smallpox
5-6 Days: Pustule rash and Scabs: Bumps become round, deep, and embedded into the dermis Scabbing will occur Still contagious
Fourth stage of smallpox
6+ Days: Pustule rash and Scabs: Scabs fall off and leave deep scars. Once the scabs fall off the individual is no longer contagious
Incubation for smallpox
7-19 days Incubation period No symptoms, person is not contagious
Who's at risk for varcicella?
< 2 years old Young kids No vaccination Have not had Schools or child care facilities
Who is most susceptible to Group A Streptococcus
elderly, children, individuals with wounds
Wound botulism
endospores make their way into a wound- create toxin. Usually seen following surgeries, traumatic accidents, or street-drug use.
Infant botulism
endospores reside in an infant's intestines- create toxin
Rabies reservoir
any warm-blooded animal
Immune response to botulism
adaptive immunity Treated with Botulism Antitoxin Heptavalent • Contains antibodies immunized with botulinum toxoid • Antibodies bind to toxin • Toxin cannot interact with receptors at nerve endings • Passive immunity
Group A Streptococcus mode of transmission
droplet transmission and direct contact
