Mastering Mod 4 ch 16-19
The development of a pseudomembrane on the tonsils and throat is characteristic of streptococcal pharyngitis. tuberculosis .pertussis. diphtheria. pneumococcal pneumonia.
diphtheria.
Pyocyanin, a greenish-blue pigment produced by pseudomonads, acts as a virulence factor by digesting lipids in tissues. generating reactive oxygen species. breaking down reactive oxygen species. forming a biofilm. lysing red blood cells.
generating reactive oxygen species.
Histoplasmosis should be suspected in cases of fungal respiratory infections found in construction workers. HIV-AIDS patients. the Mississippi and Ohio River valley regions. dog owners. cattle or dairy farm workers.
the Mississippi and Ohio River valley regions.
Which of the following is the best way to treat Cryptococcosis?
Adminstering antifungal drugs Adminstering antifungal drugs, such as amphotericin B or flucytosine, would be the best treatment option for a patient suffering from Cryptococcosis. Cryptococcosis is caused by the fungal organism Cryptococcus neoformans. It is transmitted by inhalation of fungal spores from dried bird droppings. Once they enter the lungs, they invade macrophages and grow inside them. These macrophages migrate out of the lungs to the lymphatic system, carrying the fungi with them. From there, the organism can infect the blood and invade the CNS and cause Cryptococcosis. Because the organism is fungal, administration of antibiotics such as penicillin, antivirals, or antitoxins would not be effective.
Which of the following is not a zoonosis?
All are considered zoonotic infections. Rabies West Nile virus Toxoplasmosis Rabies virus is contracted through a bite of an infected animal or by breathing aerosolized droppings. West Nile virus is usually passed from birds to humans via mosquito or tick bites. The most common mosquito vectors for West Nile virus are part of the Culex genus. The causative agent of toxoplasmosis, Toxoplasma gondii, is mostly transmitted by ingestion of undercooked meat containing T. gondii cysts and through exposure with cat feces.
Human prion disease (vCJD) has been linked to eating contaminated _________
Beef In 1996, a human prion disease called vCJD (variant Creuztfeldt-Jakob disease) was linked to eating beef contaminated with bovine spongiform encephalopathy prions. Hundreds of people in the United Kingdom died in this outbreak. Deer have been shown to contain species-specific prions that cause chronic wasting disease (CWD). Pork and chicken have not been linked to prions.
A middle-aged adult female is displaying the following symptoms: nausea, vomiting, flaccid paralysis in her extremities, and difficulty breathing. She reported that she had consumed home-made, canned vegetables. What is she most likely suffering from?
Botulism The patient is likely suffering from botulism. Botulism is caused by Clostridium botulinum, a Gram-positive, rod-shaped, endospore-forming, obligate anaerobe. It has very specific growth needs—absence of oxygen, low pH, and salt. Canned vegetables such as beets, carrots, and spinach provide the perfect growth conditions for the endospores to germinate and produce the potent exotoxin. The Botulinum toxin causes flaccid (relaxed) paralysis. This condition occurs because the toxin blocks the release of the neurotransmitter acetylcholine from neurons and thereby prevents muscle contraction. Other signs and symptoms are nausea, vomiting, muscle cramps, difficulty breathing, drooping eyelids, and difficulty speaking. Tetanus is caused by Clostridium tetani. The toxin produced by this organism has the opposite effect of the botulism toxin. It prevents the re-uptake of acetylcholine, and muscles are continuously stimulated to the point of "tetanus" or spastic paralysis. Listeriosis is caused by Listeria monocytogenes. It is also acquired through contaminated food, but it does not have an effect on the muscle function of an infected patient. Cryptococcosis is caused by Cryptococcus neoformans. It is acquired through inhalation of spores; once they enter the lungs, they invade macrophages and grow inside them. These macrophages migrate out of the lungs to the lymphatic system, carrying the fungi with them. From there, the organism can infect the blood and invade the CNS.
Which of the following genera is not commonly found in dental plaque?
Campylobacter jejuni Campylobacter is not found in dental plaque. C. jejuni is a Gram-negative, flagellated, spiral-shaped bacterium that grows best in microaerophilic (limited oxygen) conditions. The bacterium is commonly found in the intestinal tract of healthy birds—most notably in chickens. As such, C. jejuni infections are primarily associated with eating undercooked poultry or cross-contaminating foods with raw poultry juices. In general, Streptococcus and Actinomyces species are among the first to begin attaching to the tooth enamel. Other bacterial genera such as Veillonella and Haemophilus may attach next, creating the complex biofilm called dental plaque.
Which of the following organisms causes food infection?
Campylobacter jejuni Food infection is caused after ingestion of a pathogen which then establishes itself in the host. Symptoms may appear 1-5 days (or longer) after exposure. Campylobacter jejuni, Shigella species, E. coli, Salmonella species, and Listeria monocytogenes are common bacterial agents that cause food infection. Food poisoning is caused by an ingested toxin that causes the illness symptoms. These toxins are commonly secreted by bacterial agents such as Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens. Symptoms may appear 30 minutes to 6 hours after exposure.
A patient is presenting with the following signs and symptoms: diarrhea, abdominal cramps, vomiting, and fever. The patient indicated consuming slightly undercooked chicken three days ago. What is the patient likely suffering from?
Campylobacteriosis The patient is likely suffering from Campylobacteriosis, which was caused by the Gram-negative bacterium Campylobacter jejuni. Chickens naturally harbor the bacteria in their intestines, so cross-contamination by raw chicken is the main transmission mode, along with fecal-oral. Hygienic handling of raw chicken, washing hands and surfaces to prevent cross-contamination, and fully cooking poultry prevents infections. Signs and symptoms include diarrhea, abdominal cramps, vomiting, and fever. Outbreaks of infections with enterohemorrhagic Escherichia coli are associated with contaminated meat, unpasteurized dairy and juice products, and produce washed or watered with feces-contaminated water. Incubation period is 1-10 days. Signs and symptoms include watery diarrhea that may turn bloody, abdominal pain, and vomiting; usually there is not a fever. Symptoms of cholera include vomiting, profuse and watery diarrhea. It is contracted by ingestion of contaminated water in areas lacking proper sanitation. Diarrhea, fever, abdominal pain, and nausea are signs and symptoms for infections with C. difficile. Most cases are found in elderly or immunocompromised patients who have had an extended stay in a healthcare facility and recent antibiotic therapy.
Why should a pregnant woman avoid changing and cleaning cat litter boxes?
Cat feces may contain the protozon Toxoplasma gondii, which can cross the placenta and infect the fetus. Pregnant women are advised against changing cat litter boxes because cat feces may contain the protozon Toxoplasma gondii, which can cross the placenta and infect the fetus. Once T. gondii oocysts enter the body, they may develop into a pathogenic form of the protozoan called tachyzoites. This is a motile form that can invade tissues. If a pregnant mother has an acute infection or if the cysts in her tissue reactivate to become tachyzoites, the protozoan can cross the placenta and infect the fetus. There it invades nervous tissue and can cause convulsions, deafness, or learning disabilities. Sometimes, a fetal toxoplasmosis infection can cause miscarriage.
The main causative agent of gas gangrene is ___________. Streptococcus pyogenes Clostridium perfringens Bacillus anthracis Pseudomonas aeruginosa
Clostridium perfringens
Which protective mechanism of the eye is incorrectly matched with its description? Lactoferrin: Binds up free iron which some microbes require Lysozyme: Breaks down bacterial cell walls Tears: Washes away microbes and contains antimicrobial chemicals Lacrimal gland: Produces tears Conjunctiva: Transparent layer which protects the iris
Conjunctiva: Transparent layer which protects the iris
_________ is the term used to describe an inflammation of the brain.
Encephalitis Encephalitis is the term used to describe an inflammation of the brain. Meningitis is the term used to describe an inflammation of any of the three meninges. A coma is a prolonged state of unconsciousness that resists waking. Meningoencephalitis is the term used to describe a concurrent inflammation of any of the meninges and the brain.
Which staphylococcal infection is not correctly matched with its description? Cellulitis: Deep infection of the lower dermal and subcutaneous fat Erysipelas: A milder form of impetigo with only localized inflammation and mild pain Folliculitis: Swollen, red, pus-filled hair follicles Impetigo: Presence of pus-filled vesicles on the face, lips, or extremities, usually in children Scalded skin syndrome: Caused by the production of an exfoliative toxin
Erysipelas: A milder form of impetigo with only localized inflammation and mild pain
Which of the following is not a key virulence factor of Shigella?
Erythrogenic toxins Erythrogenic toxins are produced by Streptococcus spp. They are membrane-acting extracellular toxins that may damage skin capillaries and produce a red rash characteristic of scarlet fever. Shigella species have numerous other virulence factors. Some key virulence factors are: (1) a system that induces host cells to endocytose the bacteria; (2) the manufacture of several exotoxins that damage intestinal cells and induce fluid efflux; (3) the capacity to pass between infected cells using an actin propulsion system; and (4) the ability to infect macrophages and induce apoptos
Consuming undercooked, contaminated hamburgers and unpasteurized dairy and juices may become sources of infection with ______________
Escherichia coli O157:H7 Consuming undercooked, contaminated hamburgers and unpasteurized dairy and juices may become sources of infection with Escherichia coli O157:H7. Salmonella typhi is spread when human sewage contaminates water or food or when someone who is a carrier transmits the bacteria through unsanitary food-handling practices. Listeria monocytogenes causes food infection by ingestion of contaminated deli meats, cheeses, dairy, and fruits (especially cantaloupes). Vibrio cholera causes cholera and is spread by contaminated water.
Which of the following molecules are blocked from entering the cerebrospinal fluid?
Hydrophilic molecules Blood vessel cells are sealed much more tightly in the areas around the central nervous system than they are in other areas of the body. Oxygen and lipophilic (fat-loving) molecules can pass through these capillary cells. Larger essential molecules such as glucose have special transporters to help them cross. But most other molecules, including those that are hydrophilic, are blocked from entering the cerebrospinal fluid.
After your dog drank puddle water at the dog park a few days prior, he is now suffering from severe diarrhea. The vet observed cysts in his stool sample. Which organism likely infected your dog?
Giardia lamblia Giardia lamblia is the most common intestinal parasite; it is usually acquired by swallowing feces-contaminated food or water, but can also be transmitted from person to person or from animals to people. People at risk include backpackers and campers who drink untreated water from lakes, ponds, or streams; people in areas that have experienced hurricanes, flooding rains, or other natural disasters that compromise sewage and water management; and anyone who has close contact with an infected person. Hymenolepis nana is the single most common cause of tapeworm infection in humans. In their adult form, H. nana worms are less than two inches long, which is why they are also called dwarf tapeworms. Most infections are transmitted person to person via the fecal-oral route when the worm's eggs are ingested in food or water contaminated with human feces. Necator americanus are soil-transmitted roundworms. When human feces harboring eggs is deposited in the soil by a person defecating outside, through poor sewage management, or by using human waste as fertilizer, the eggs hatch and mature into adult worms that burrow into bare feet and legs. Ascaris lumbricoides is among the most prevalent helminthic infections in people. This roundworm is most common in tropical and subtropical regions with poor sanitation measures or areas that use human fecal mater to fertilize crops.
_____________ is transmitted mainly via the fecal-oral route.
Hepatitis A Hepatitis A is transmitted mainly fecal-oral, with contact transmission rarely. It is prevented with vaccine and proper hygiene/hand washing. Hepatitis B is a bloodborne disease that is transmitted sexually and vertically (mother to child). It can be prevented with a vaccine as well as condom usage and not sharing needles. If a pregnant woman is infected, a vaccine is administered to the infant within 12 hours of birth. Hepatitis C is a bloodborne disease that is transmitted sexually and vertically (mother to child). There is no vaccine, so prevention involves condom use and not sharing needles. Hepatitis D is a bloodborne disease that is transmitted sexually and vertically (mother to child). Hep B vaccine protects against Hep D as well. Other prevention methods include condom use and not sharing needles.
When should an individual that was bitten by a rabid animal seek medical treatment?
Immediately after exposure An individual bitten by a rabid animal should seek help immediately after exposure. During treatment, patients will be injected with both antirabies antibodies and the inactivated vaccine for rabies, a regime called rabies postexposure prophylaxis. This allows the body to produce an effective immune response to fight off the initially slow-growing virus. Once fever, nausea, and a pins-and-needles sensation around the wound develops, the disease rapidly progresses. These initial symptoms last 2-10 days, followed by a collection of neurological symptoms that usually last no longer than a week. These final neurological symptoms include pharyngeal spasms, confusion, loss of coordination, delirium, and the characteristic hydrophobia. Coma, cardiac arrest, and respiratory failure follow neurological symptoms. After the onset of neurological symptoms, rabies is almost always fatal.
Which of the following would not likely protect you from digestive system infections?
Increasing sugar intake Increasing sugar intake would not prevent digestive system infections. It would likely increase periodontal disease and dental caries. Proper handwashing prevents diseases such as rotaviral gastroenteritis, hepatitis A, campylobacteriosis, or infections with Staphylococci or Clostridium perfringens. Undercooked meats (chicken, beef, or wild game) may also transmit pathogens, such as Campylobacter jejuni, Shigella sonnei, and Ascaris lumbricoides. Wearing shoes may prevent infections with Necator americanus.
Which of the following is considered the most common healthcare-acquired infection?
Infections with Clostridium difficile The CDC has put Clostridium difficile at the top of the list of emerging public health threats. According to the CDC, every year up to half a million people develop C. difficile infections, and as many as 29,000 of them die. About 75 percent of cases occur in older people with a history of a hospital stay, or residents of long-term-care facilities. It is also increasingly common for children, people who do not report prior antibiotic therapy, and people who do not have a hospitalization history to be affected. C. difficile is now considered the most common healthcare-acquired infection, surpassing even MRSA (methicillin-resistant Staphyoloccus aureus).
Which statement is not true about leishmaniasis? It is a slow infection that can persist for months to years. It is transmitted by sand flies. It is most prevalent in the tropics and subtropics. Over twenty different Leishmania species may cause leishmaniasis. It is preventable by a vaccine which is recommended for travelers to endemic areas.
It is preventable by a vaccine which is recommended for travelers to endemic areas.
Which of the following statements about Amebiasis is correct?
It is transmitted via contaminated water. Amebiasis transmits via the fecal-oral route (e.g., contaminated water), direct contact, or contaminated fomites. The life cycle of the causative agent of amebiasis, Entamoeba histolytica, is similar to Giardia lamblia in that it consists of two stages: cyst and trophozoite. Signs and symptoms include dysentery, severe abdominal cramping, and low-grade fever. Invasive disease may develop when trophozoites release enzymes that kill epithelial cells and cause ulcers. If trophozoites enter the bloodstream they can cause abscesses in the liver, lungs, and (very rarely) the brain. All infections should be treated because the protozoan can cause invasive disease. Metronidazole is prescribed first, followed by paromomycin.
Which of the following would be symptoms found specific for bacterial meningitis?
Lethargy and rash Lethargy and rash would be specific symptoms indicating the possibility of bacterial meningitis. Headache, stiff neck, photophobia, and vomiting could indicate either viral or bacterial meningitis. Disorientation and seizures could be symptoms of encephalitis.
Which statement does not apply to pneumocystis pneumonia and its causative organism, Pneumocystis jirovecii? The organism has some characteristics found in protozoans rather than fungi. Serological evidence suggests that most people are exposed to the organism in early childhood. The fungus does not make spores. HIV-AIDS patient are high-risk for this infection. Like all other pathogenic fungi, the reservoir is soil.
Like all other pathogenic fungi, the reservoir is soil.
Which of the following test results would support that a patient is suffering from bacterial but not viral meningitis?
Lower glucose concentration found in the cerebrospinal fluid Lower glucose concentration found in cerebrospinal fluid (CSF) samples would be supporting evidence for bacterial meningitis. Viral meningitis does not affect glucose levels in the CSF. But bacteria in the CSF lower the usual glucose amount, as they use it as an energy and carbon source. Higher protein content is indicative of both bacterial and viral meningitis. Slightly elevated white blood cell count (usually less than 300/mm3) and low or no pressure released during lumbar puncture are indicative of viral meningitis.
Which of the following is not a Staphylococcus aureus virulence factor? Exfoliative toxin A polysaccharide capsule Coagulase M-protein
M-protein Correct You selected the false statement. S. aureus does not make M-protein.
During a pertussis infection, the pathogenic bacterium Bordatella pertussis produces tracheal cytotoxin, which destroys cilia. Which of the following would most likely result from ciliary destruction? Aspiration of food and beverage into the lungs Temporary voice loss due to the swelling of the vocal chords Mucus would accumulate in the respiratory tract. The windpipe would be physically obstructed.
Mucus would accumulate in the respiratory tract.
Hansen's disease is caused by ___________ and is often linked to exposure to _________.
Mycobacterium leprae; armadillos Hansen's disease is caused by Mycobacterium leprae and is often linked to exposure to armadillos. When the organism infects peripheral nerves, the immune system reaction can cause flattened skin lesions (tuberculoid leprosy) or disfiguring and often deadly manifestations (lepromatous leprosy). The bacteria damage peripheral nerves, causing muscle weakness and loss of sensation. Armadillos are natural carriers of the bacterium, probably due to their cooler body temperature (30-35°C), which is necessary for M. leprae's growth. The few hundred cases diagnosed each year in the U.S. are often linked to exposure to armadillos.
The Gram stain of the CSF from a patient suffering from headaches, stiff neck, and petechial rash reveals the presence of Gram-negative diplococci. A follow-up capsule stain was also positive for the presence of capsules. With which organism is the patient likely infected?
Neisseria meningitis The patient is likely infected with Neisseria meningitidis, a capsulated Gram-negative aerobe, and is suffering from meningococcal meningitis. The symptoms of meningococcal meningitis are similar to those of other types of bacterial meningitis. However, a distinctive petechial rash that progresses to larger bruise-like lesions is found in cases where N. meningitidis invades the bloodstream. Listeria monocytogenes is a Gram-positive rod and does not produce capsules. Though Haemophilus influenzae is also Gram-negative, it would not cause the appearance of a petechial rash. Streptococcus pneumoniae produces capsules but it is a Gram-positive organism.
Cryptosporidium has a complex life cycle. Which of the following is the infectious form of the parasite?
Oocysts Cryptosporidium enters its host as oocysts, spore-like structures that survive lengthy periods outside a mammalian host. Upon entering the intestines, the oocysts then release sickle-shaped sporozoites into the intestine. The sporozoites attach to epithelial cells to multiply, inciting an inflammatory response. The parasites then undergo asexual reproduction and later sexual reproduction to make macrogametes (female) and microgametes (male). The microgametes then fertilize the macrogametes to produce the oocysts, which are the infectious form of the parasite that gets excreted with feces.
In addition to raw eggs, undercooked chicken products, and seafood, which of the following has also been associated with Salmonella enterica serovars infections?
Pet reptiles Poultry products are most likely to harbor Salmonella serovars that infect people. The bacterium is commonly detected in raw chicken and eggs, both inside and on the outside of shells. Raw eggs, undercooked meat or seafood, and produce that has been washed or watered with feces-contaminated water are all potential sources of infection. Additionally, pet reptiles (especially turtles) have been associated with Salmonella infections.
For which of the following infections is a vaccine available?
Pneumococcal meningitis Pneumococcal meningitis, caused by Streptococcus pneumoniae, can be prevented by a vaccine. Haemophilus influenzae type b meningitis (Hib) used to be one of the most common forms of meningitis, but it is now rare thanks to the Hib vaccine. Many people harbor H. influenzae among the normal microbiota of the throat. There are no vaccines available to prevent primary amoebic meningoencephalitis (caused by Naegleria fowleri), African sleeping sickness (caused by Trypanosoma brucei), or Cryptococcosis (caused by Cryptococcus neoformans)
Your 3-year-old patient presents to you with high fever, shaking chills, cough, chest pain, and shortness of breath. The patient's mother stated that symptoms began suddenly last night. The patient is up to date on all vaccinations. Based on this information, which of the following diseases did your patient most likely contract? Haemophilus pneumonia Pontiac fever Walking pneumonia Pneumococcal pneumonia
Pneumococcal pneumonia
Which of the following is mainly found in immunocompromised patients?
Pneumococcal pneumonia Pneumococcal pneumonia is usually an opportunistic infection that occurs when the causative agent Streptococcus pneumoniae invades the blood stream of immunocompromised patients. A capsule helps the organism adhere to airway mucous membranes and evade phagocytosis, and a toxin called pneumolysin allows the pathogen to lyse phagocytic cells. Toxins and antigens stimulate inflammation and tissue damage, which allows the bacteria access to the blood (bacteremia) and changes the permeability of the blood-brain barrier, causing meningitis. African sleeping sickness, Creutzfeldt-Jacob disease, and Toxoplasmosis are caused by true pathogens.
Which of the following infectious agents infects the peripheral nervous system (PNS)?
Poliovirus Poliovirus infects the peripheral nervous system. The vius is typically spread through the fecal-oral route via contaminated water or hands. The tough protein coat protects it from stomach acid, allowing it to reach and bind to intestinal cells. From there, the poliovirus travels to skeletal muscle cells, replicates, and progresses up motor neurons to the CNS. Poliovirus is cytolytic, causing rapid cell rupture after infection and viral replication. This lysis of infected neurons causes severe inflammation, giving the disease its name: inflammation of the myelin, or myelitis. Very few polio patients progress to the most serious stages of the disease. Most cases only present with flu-like symptoms. Prions, West Nile virus, and Naegleria fowleri are all linked to infections of the central nervous system.
Recent studies have found that resident microbes in the digestive system may actually exert some influence on nervous system functions. A recent study found that people experiencing depression had lower levels of ___________ in their GI tract than people that did not suffer from depression.
Proteobacteria Recent studies have found that resident microbes in the digestive system may actually exert some influence on nervous system functions. The term "gut-brain axis" describes the complex, back-and-forth communication that occurs between the endocrine, immune, and nervous systems and the gastrointestinal tract. The profile of resident bacteria populations of the gut has already been linked to certain autoimmune and now also nervous system disorders. A recent study found that people experiencing depression had lower levels of Proteobacteria in their GI tract than people that did not suffer from depression. The GI tracts of those suffering from the neurodegenerative disorder Parkinson's disease have decreased levels of Prevotella bacteria, and greatly increased levels of Enterobacteriaceae species compared with healthy individuals. Mycobacterium leprae and Clostridium botulinum are pathogens that cause Hansen's disease and Botulism, respectively.
A patient arrives at the hospital ER displaying symptoms of hydrophobia, hallucinations, and disorientation. The family mentioned that the patient was recently bitten by a bat. Which disease is this patient likely suffering from?
Rabies The patient is likely suffering from rabies. Rabies is a zoonotic disease in which the causative rabies virus is acquired through an animal bite, e.g. from an infected bat, racoon, or dog. The prognosis for survival is very poor once neurological symptoms, e.g. hydrophobia, hallucinations, and disorientation (all of which the patient is experiencing), are present. The disease will rapidly progress, and the patient is likely going to die. Signs and symptoms of West Nile virus are fever, headache, and flu-like symptoms. It is a zoonotic disease transmitted by a mosquito vector. Symptoms of polio are flaccid paralysis and myelitis. It is commonly transmitted through the fecal-oral route. Signs and symptoms of listeriosis are fever, headache, stiff neck and back, and confusion. The causative agent Listeria monocytogenes is acquired through unpasteurized dairy products, sprouts, and fruits.
Which of the following diseases is incorrectly matched with its characteristics? Hand, foot, and mouth disease: mild disease that is mainly caused by coxsackievirus A16 and enterovirus 71 Roseola: rare childhood infection that tends to present without a fever Fifth disease: caused by a parvovirus and presents with a red facial rash Rubella: also known as German measles and presents with a rash and swollen lymph nodes
Roseola: rare childhood infection that tends to present without a fever Correct You found an incorrect match. Roseola is a common childhood infection that although usually asymptomatic, may present with a high fever and rash.
Which of the following diseases can be prevented by vaccine?
Rotavirus gastroenteritis Worldwide, rotavirus is the leading cause of rotavirus gastroenteritis in children under five years old. This RNA virus also infects adults, but symptoms are usually mild and may go unnoticed. Most cases are acquired through fecal-oral transmission, in which contaminated food or water is ingested. However, contaminated inanimate objects, or fomites, can also transmit the virus. Vaccinations combined with maintaining good hygiene practices, such as washing hands before food preparation and eating, and access to sanitized water limit transmission. There are currently no vaccines available to prevent Hepatitis C, Campylobacteriosis, and Shigellosis.
For the past days, you have observed your four-year-old daughter frequently itching her anal area. You suspect that she may be infected with Enterobius vermicularis and take her to see a doctor. How will the doctor confirm your suspicion and what will be the suggested treatment?
Tape adhesion test of the anal region for eggs and treat with over-the-counter medication The doctor will likely perform a tape adhesion test, which will detect the eggs of the organism Enterobius vermicularis. The sticky side of clear tape is pressed against the perianal region and then examined for eggs. The infection is treated with over-the-counter medications such as pyrantel pamoate. When one person is diagnosed, the whole household will be treated simultaneously to prevent further spread
Why is tetanus commonly associated with deep puncture wounds?
The causative agent Clostridium tetani is an anaerobic, spore-forming organism. Deep puncture wounds provide an optimal growth environment for Clostridium tetani because it is an obligate anaerobic, spore-forming organism. Deep puncture wounds do not allow for oxygen to penetrate as superficial abrasions do, thus allowing the organism to germinate and replicate. Clostridum tentani is a soil-dweller that is found in soils all over the world. Once the organism is actively dividing and metabolizing, it releases the potent toxin tetanospasmin, which causes irreversible damage to neurons. The toxin is taken up by peripheral motor neurons and transported to the spinal cord. Once there, it becomes active and blocks the release of inhibitory neurotransmitters, preventing muscle relaxation.
Which of the following best describes the peripheral nervous system?
The peripheral nervous system (PNS) inputs and transmits information to the body. The human nervous system is divided into two major segments that accomplish two different tasks within the body. The peripheral nervous system (PNS) inputs and transmits information, while the central nervous system (CNS) integrates information received and sends back an "action plan" to respond to stimulus from the environment. Nerves comprise the peripheral nervous system, while the spinal cord and brain make up the central nervous system.
________________ is caused by a Chlamydia species and is the leading cause of preventable microbial blindness. Viral keratitis Acanthamoeba keratitis Trachoma River blindness
Trachoma
Your patient is suffering from fever and complaining of fatigue, chills, and muscle pain. He stated that he returned from a hunting trip about two weeks ago where he had consumed undercooked wild game. What is he likely suffering from?
Trichinellosis Your patient is likely suffering from Trichinellosis. Worldwide, this roundworm is acquired by eating raw or undercooked wild game meat or pork that contains the parasite. This is a zoonotic infection that is normally transmitted from animals to humans, with the humans serving as an accidental host that is a dead end for the parasite, as we are not a food source. Symptoms of nausea, diarrhea, or vomiting develop within a few days of eating the contaminated meat. Two weeks later muscle pain, fever, headache, chills, and rash may occur. Norovirus (or Norwalk virus) is the leading cause of acute viral gastroenteritis in the United States. The RNA virus is extremely contagious, as only 20 particles are required for infection. Feces and vomit serve to spread the virus via a fecal-oral route. Symptoms develop within 12 to 48 hours of ingesting the virus. Ascariasis is usually asymptomatic. It is a mild infection that can cause abdominal pain, nausea, diarrhea, or bloody stools. With high worm load patient may develop aforementioned symptoms, plus fatigue, vomiting, weight loss, malnutrition, or bowel obstruction. Pinworm infections are caused by white roundworms that reside in the colon and are only about 4-12 millimeters long. When the infected person is asleep, the female worm migrates to the periphery of the anus to lay eggs. Disturbed sleep, teeth grinding, and an itchy anus are common symptoms.
Which subspecies accounts for 98% of all cases of African sleeping sickness?
Trypanosoma brucei gambiense The flagellated protozoan Trypanosoma brucei causes African sleeping sickness, a debilitating neurological disease. There are two medically important subspecies of T. brucei: rhodesiense and gambiense. These protists have different features regarding geographic distribution (although there is growing overlap), reservoirs, and disease progression in humans. Subspecies T. b. rhodesiense is rare and causes a more rapid and acute disease, with patients often dying from cardiac arrest before neurological symptoms emerge. Subspecies T. b. gambiense causes a more chronic disease and accounts for 98% of all African sleeping sickness cases.
Which of the following tests is done to indirectly identify the presence of Helicobacter pylori in the stomach of a patient?
Urea breath test Helicobacter pylori antigens can be detected in stool, or antibodies to the bacterium can be found in blood samples. A urea breath test can indirectly identify the presence of the bacterium by detecting urea made by the organism. Biopsy of the stomach lining during endoscopic evaluation can also confirm diagnosis. Treatment is dual antibiotic therapy (often clarithromycin and amoxicillin) along with a proton pump inhibitor to reduce stomach acidity so the ulcer may heal.
Which statement is not true about viral warts? Warts can be removed but may return later. Warts can spread from one part of the body to another via autoinoculation. Warts result from abnormal cell growth and so are highly likely to become cancerous. Papillomaviruses are the cause of many warts. Plantar warts are found on the feet.
Warts result from abnormal cell growth and so are highly likely to become cancerous.
In streptococcal toxic shock syndrome, pathology results from toxins in the bloodstream which may cause both a red skin rash, as well as release of foul-smelling gases from the infection site. peeling away of the epidermal layer of skin. degradation of connective tissue. a decrease in blood pressure leading to organ failure. formation of a blue- or green-colored pus.
a decrease in blood pressure leading to organ failure.
Although each of the following viral groups causes acute respiratory illnesses, ________ can also be associated with conjunctivitis, gastroenteritis, or cystitis. human parainfluenza virus influenzas virus adenovirus coronavirusrespiratory syncytial virus
adenovirus
The infectious agent that causes tuberculosis is HIV. unpasteurized milk. one of several Gram-negative bacterial species. avian influenza virus. an acid-fast bacterium of the genus Mycobacterium.
an acid-fast bacterium of the genus Mycobacterium.
Cutaneous mycoses usually occur in the deeper dermal layers or in muscles. are invasive with a considerable risk of fatality. are superficial infections on the skin, hair, or nails. respond quickly to treatment with a single dose of topical antifungal medication. are not associated with changes in the normal microbiota.
are superficial infections on the skin, hair, or nails.
A child with no known congenital problems is diagnosed with inflammation of the heart valves. The medical history of the child is unremarkable except for a sore throat and fever six weeks prior, which the parents attributed to a common cold. The heart valve inflammation is most likely due to autoimmune complications of Streptococcus pyogenes. Bordetella pertussis. tuberculosis. atypical pneumonia. Corynebacterium diphtheriae.
autoimmune complications of Streptococcus pyogenes.
"Rice water" stool is a sign of __________.
cholera "Rice water" stool is a sign of cholera. The causative agent of cholera, Vibrio cholera, secretes a potent exotoxin that triggers intestinal epithelial cells to release electrolytes and water into the intestines, generating a watery, starchy-colored diarrhea or "rice water" stool. This stool may also contain flecks of intestinal mucosa—of course, it's also loaded with the cholera bacteria that will get passed on to caregivers and the environment to perpetuate the spread of this disease.
The most common cause of atypical pneumonia, Mycoplasma pneumoniae, has all the following characteristics except a parasitic lifestyle inside host cells. contains more genes than most other bacteria. difficult to see with a standard light microscope. no cell wall. one of the smallest self-replicating organisms known.
contains more genes than most other bacteria.
SARS is caused by a(n) rhinovirus. adenovirus. influenza virus. paramyxovirus. coronavirus.
coronavirus.
A two-year-old child presents to a pediatric practice with a barking cough and loud wheezing. The parent is alarmed and insists on antibiotics. What is the likely diagnosis, and are antibiotics appropriate? sinusitis / no, most cases are due to viral infections or irritants allergies / no, allergies are caused by irritants and are not infections epiglottitis / yes, this is a life-threatening bacterial infection croup / no, most cases are viral pneumonia / yes, this can be a life-threatening condition and is often bacterial
croup / no, most cases are viral
Toxins associated with food poisoning that specifically target the intestines are __________
enterotoxins Toxins associated with food poisoning that specifically target the intestines are enterotoxins that inflame intestinal cells and prevent water from absorbing into the intestine, causing diarrhea and abdominal pain. The term emetic is used to describe something that triggers vomiting. The shiga toxins target ribosomes to block protein synthesis and kill host cells. Most pathogenic Clostridium difficile strains release two exotoxins (A and B toxins).
The condition in which the stomach is inflamed is called __________.
gastritis The condition in which the stomach is inflamed is called gastritis. Dysentery is the term used for diarrhea accompanied by pain, blood, and/or mucus. Hypovolemic shock describes low blood volume due to loss of blood or severe dehydration. It can lead to organ failure. Gastroenteritis describes an inflammation of the stomach and intestines.
A 21-year-old male is admitted to the hospital in severe respiratory distress. Despite care, he died of rapid pulmonary edema within 12 hours of admission. Family members report that he had recently started work at a nearby state park. He was on a detail to clean out and renovate a group of rodent-infested rental cabins. Based on the information, what is the likely diagnosis? SARS human parainfluenza virus infection influenza H1N1 hanta pulmonary syndrome respiratory syncytial virus
hanta pulmonary syndrome
Which is not a specific cause of reactivation of HSV-1? menstruation having a cold or fever stress ultraviolet radiation hormonal changes
having a cold or fever
Onchocerciasis, or river blindness, is caused by a ________ and is spread via ________. protozoan; contaminated water virus; fomites such as towels or bedding bacterium; gnats which swarm near the eye helminth; blackflies fungus; contaminated contact lens solution
helminth; blackflies
Which factor may influence the specific types of microbes found on the skin? hormones, moisture levels, and soap and cosmetics usage moisture levels and soap and cosmetics usage moisture levels soap and cosmetics usage hormones
hormones, moisture levels, and soap and cosmetics usage
Which virulence factor of Group A streptococci (GAS) is responsible for the rapid spread of tissue death in necrotizing fasciitis? streptokinase coagulase hyaluronidase coagulase and hyaluronidase hyaluronidase and streptokinase
hyaluronidase and streptokinase
Several forms of keratitis are linked to day care centers. improper handling of contact lenses. re-activation of a herpes virus infection. hospitals or other healthcare settings. vertical transmission during childbirth
improper handling of contact lenses.
Which factor is not a reason Propionibacterium acnes (P. acnes) is often associated with acne? increased oxygen levels in clogged pores favoring bacterial growth the ability of P. acnes to metabolize sebum biofilm formation by P. acnes in pores and glands the inflammatory responses to P. acnes which causes pustules and cysts increased sebum production during adolescence
increased oxygen levels in clogged pores favoring bacterial growth
Which of the following is not a factor in increased incidence of fungal infections? climate change urban development increasing number of people living with immunosuppression increasing antibiotic resistance deforestation
increasing antibiotic resistance
Haemophilus influenzae type b is the most common causative agent of bacterial meningitis in __________.
infants and children Haemophilus influenzae type b is the most common causative agent of bacterial meningitis in infants and children. According to the CDC, before the Hib vaccine, H. influenzae type b was common in the United States and caused over 12,000 cases of meningitis in children under the age of five every year. Each year up to 600 children per year died, and as many as 4,000 became permanently disabled due to H. influenzae meningitis. In the United States it is now, on average, responsible for fewer than 20 cases of meningitis per year. However, in developing countries where vaccination campaigns can be difficult because of a lack of infrastructure, H. influenzae type b is still a serious danger to children.
Patients are infected with mumps via _____________.
infected saliva Mumps is an RNA virus that spreads among humans through infected saliva. When the mumps virus enters the nose or mouth, it quickly replicates in the upper respiratory tract. Thereafter, the virus enters the bloodstream to infect salivary glands, particularly the parotid gland. The incubation period of two to three weeks is often followed by dry mouth, fever, headache, and fatigue. Subsequent swelling under the jaw is due to inflammation of the parotid gland, termed parotitis. Because the virus is released in saliva almost a week before symptoms develop, preventing spread to others can be difficult.
Tetanospasmin affects the release of _________ neurotransmitters and causes _________ paralysis.
inhibitory; spastic Tetanospasmin, the toxin produced by Clostridium tetani, affects the release of inhibitory neurotransmitters and causes spastic paralysis. The toxin is taken up by peripheral motor neurons and transported to the spinal cord. Once there, it becomes active and blocks the release of inhibitory neurotransmitters, preventing muscle relaxation. This leads to spastic paralysis, which is an inability to relax muscles. In contrast, the botulism toxin affects the release of stimulatory neurotransmitters and causes flaccid paralysis.
Influenza differs from the common cold in that it can cause seasonal outbreaks. it is not treatable with antivirals. you can get only get influenza once. the virus is not subject to mutation. it has a greater fatality rate.
it has a greater fatality rate.
The presence of ________, a waterproofing protein, in epidermis prevents many microorganisms from gaining access to the body. keratin lysozyme antibiotics sebum melanin
keratin
Which component of the lower respiratory tract is incorrectly matched with a function or description? lungs: contain the alveolar sacs bronchi: direct air to the lungs alveoli: site of gas exchange larynx: contains the mucociliary escalator bronchioles: have ciliated mucous membranes
larynx: contains the mucociliary escalator
Which of the following skin infections is caused by a protozoan? cutaneous anthrax otitis externa leishmaniasis dermatophytic infections cutaneous candidiasis
leishmaniasis
Haemophilus influenzae causes __________.
meningitis Haemophilus influenzae received its name from where it was first isolated: flu patients. It was later found that this organism does not cause influenza and even is a common resident of the normal microbiota of healthy people. There are many serotypes of H. influenzae, though the most serious invasive strain as it relates to the nervous system is type b, which is the causative agent of Haemophilus meningitis.
A course of infection with Schistosoma is described as having three stages. During the ___________ stage a rash or itchy skin is present at the site of infection.
migratory The course of infection with Schistosoma is described as having three stages: migratory, acute, and chronic. The migratory phase occurs within a few days of initial infection and is characterized by a rash or itchy skin at the site of migration. Some people then progress to an acute phase. If this stage is going to develop, it tends to do so within 2 months of initial infection and coincides with the first wave of egg release. In the acute stage the patient develops fever, chills, cough, and muscle aches. The chronic stage is related to deposition of eggs in vessels and tissues. While eggs make their way toward the intestines or bladder, a number of them are swept up in the blood circulation and instead lodge in blood vessels and various tissues around the body to cause varied and potentially deadly symptoms. With chronic infection, additional symptoms of abdominal pain, enlarged liver, and swollen abdomen may be present. The paroxysmal stage is a phase found in whooping cough caused by Bordetella pertussis.
These two secondary lesions arise when bleeding or burst capillaries occur in the skin. crust and scale cysts and ulcers petechiae and purpura bullae and vesicles papular and maculopapular rashes
petechiae and purpura
Tissue necrosis caused by Clostridium perfringens may be distinguished from necrotizing fasciitis in what way? emission of foul-smelling gases from the damaged tissue presence of Gram-positive, endospore forming bacilli in the affected area and emission of foul-smelling gases from the damaged tissue emission of foul-smelling gases from the damaged tissue and presence of Gram-positive, catalase-negative cocci in the affected area presence of Gram-positive, endospore forming bacilli in the affected area presence of Gram-positive, catalase-negative cocci in the affected area
presence of Gram-positive, endospore forming bacilli in the affected area and emission of foul-smelling gases from the damaged tissue
What role do capsules and protein A play as virulence factors of Staphylococcus aureus? lyse red blood cells form blood clots protect the bacterium from neutrophils protect the bacterium from phagocytosis break down blood clots
protect the bacterium from phagocytosis
Endemic mycoses are easily transmitted person-to-person. caused by species who inhabit multiple ecological niches. unable to establish infections in healthy people. restricted to a specific geographic location. due to changes in the patient's normal microbiota.
restricted to a specific geographic location.
Latent tuberculosis will result in a negative tuberculin skin test. is easily spread through respiratory droplets. will eventually progress to active TB in most individuals. results when M. tuberculosis bacteria are phagocytized and effectively walled off within granulomas in the lungs. accounts for only a small minority of cases.
results when M. tuberculosis bacteria are phagocytized and effectively walled off within granulomas in the lungs.
Which factor, beginning in 1995, is responsible for the decline in chicken pox from a routine childhood disease to a rare infection? ecological changes affecting the natural reservoir of the virus routine vaccination changes in global migration patterns natural evolution of the virus to a less virulent form development of effective anti-viral medications
routine vaccination
Pertussis is characterized by severe coughing attacks where the patient struggles to catch their breath. a pneumonia-like infection acquired from air conditioning or water systems. high prevalence among those who handle birds.a positive tuberculin skin test. a high fever with a bright red rash across the body.
severe coughing attacks where the patient struggles to catch their breath.
Lactobacilli and Bacteroides are part of the microbiome associated with the _____________
small and large intestines Lactobacilli and Bacteroides are part of the microbiome associated with the small and large intestines. The most common residents in the mouth and on the tongue and gums are Streptococcus species. The teeth are mainly colonized by a variety of Streptococcus, Neisseria, Fusobacterium, and Actinomyces species. Helicobacter pylori resides in the stomach.
A key factor in the high prevalence of otitis media in children is the lack of a mature microbiome in the auditory canal. the maturing of the innate and adaptive immune responses in children. children are more likely to suffer from colds and influenza than adults. the orientation of the eustachian tube in children prevents efficient fluid drainage. children do not complete their routine vaccine schedule until adolescence.
the orientation of the eustachian tube in children prevents efficient fluid drainage.
The best way to prevent the spread of a norovirus infection among a population is ____________.
the speedy decontamination of surfaces with chlorine bleach solution Norovirus (or Norwalk virus) is the leading cause of acute viral gastroenteritis in the United States. It is spread by fecal-oral transmission (usually via contaminated surfaces). No vaccine is currently available, so prevention involves decontamination of surfaces with chlorine bleach solution and hand washing.
Influenza A strains are characterized by whether or not humans are infected. the type of animal in which the strain originated. whether the virus contains DNA or RNA. the type of HA and NA spikes found on the viral surface. the country in which the strain originated.
the type of HA (Hemagluttinin)and NA (Neuramidase) spikes found on the viral surface.
Vaccine prevention of acute respiratory infections (the common cold) is unlikely because antibiotics easily cure the common cold.there is a relatively low social and economic cost associated with the common cold. humans do not generate a strong immune response to common cold viruses. colds are easily misdiagnosed as something else. there are many distinct virus strains and serovars that cause the common cold.
there are many distinct virus strains and serovars that cause the common cold.
A fungal species which can grow in varied climates and under diverse conditions is termed normal. microbiotic. ubiquitous. mycosis. endemic.
ubiquitous.
A parent calls the pediatrician's office about uncomfortable sores on the inside of her child's mouth. You suspect hand, foot, and mouth disease (HFMD), but need to rule out measles. Which information could help you to rule out measles? presence of a rash on the face, trunk, and extremities vaccination history vaccination history and other symptoms of illness such as fever and sore throat other symptoms of illness such as fever and sore throat vaccination history, other symptoms of illness such as fever and sore throat, and presence of a rash on the face, trunk, and extremities
vaccination history
A small child presents to the pediatric office with a reddened sclera, itchy eyes, and a watery, clear discharge from the affected eye. The most likely diagnosis is viral conjunctivitis. bacterial conjunctivitis. trachoma. either bacterial conjunctivitis or trachoma; further tests are needed. cannot be distinguished between bacterial or viral conjunctivitis so antibiotic treatment is given regardless.
viral conjunctivitis.
The upper respiratory tract is lined with mucous membranes which secrete mucous. What is the purpose of mucous? cools and dries the air we breathe cools and dries, and traps microbes from the air we breathe warms and humidifies, and traps microbes and debris from the air we breathe warms and humidifies the air we breathe traps microbes and debris from the air we breathe
warms and humidifies, and traps microbes and debris from the air we breathe
The demographic most at risk from respiratory syncytial virus are the elderly. pet owners. immunocompromised individuals. young children. smokers.
young children.