The Quizzes about Parasitology – Part 2 (end)

An African local clinic reports seeing increased cases of central nervous system (CNS) involvement in patients. Genetically induced changes in the glycoprotein coat of which one of the following organisms enhances its escape from the host’s immune antibody response by having genes that encode multiple, variant surface glycoproteins?

Human parasitic amoebas are usually ingested for transmission. In less acute disease, patients may experience abdominal tenderness, abdominal cramps, nausea, vomiting, and diarrhea. Which of the following best describes these intestinal amebas?

A boy scout troop goes camping in a New England forest area in the late spring. Two weeks later, several of the boys present with erythema migrans lesions but no other clinical manifestations. Borrelia burgdorferi, the causative agent of Lyme disease, has been isolated from a variety of ticks such as I. scapularis, Amblyomma, Dermacentor, and I. pacificus. Which of the following statements most accurately describes Lyme disease?

A male patient in a tropical environment has eosinophilia during acute inflammatory episodes of his illness, but this is not considered to be the definitive diagnostic feature to determine what is causing his disease. Transmission of human parasites may occur via ingestion of contaminated food, water, snails, a variety of insects, and possibly even through pets or rat ectoparasites. Which of the following requires a mosquito for transmission?

A Brazilian farmer presents to his medical clinic with hepatosplenomegaly with ascetic fluid in the peritoneal cavity. His liver is studded with white granulomas. He is treated with praziquantel. Which of the following organisms is endemic in Africa and South/Central America and is transmitted by skin penetration (by eggs with a large lateral spine), resulting in a dermatitis and katayama fever (serum sickness-like syndrome with fever, lymphadenopathy, and hepatosplenomegaly)?

The adults in a village in southern China suffer from fever, chills, mild jaundice, eosinophilia, and liver enlargement. Which of the following organisms may be ingested with raw fish, often resulting in an asymptomatic infection but, with a heavy infection, may cause biliary and bile duct obstruction and has an operculated egg?

Which of the following organisms is endemic in Asia, and has a small lateral egg spine, and in chronic disease may result in hepatosplenic disease, portal hypertension, and liver granulomas?

An African rice farmer, who depends on irrigation water from a regional lake, develops hematuria and dysuria severe enough to have concern for renal failure. Which of the following organisms has large terminal egg spines, may cause a chronic granulomatous bladder disease with urethral obstruction, chronic renal failure, and may be detected via eggs in the urine?

Campers in a European forest area drink unfiltered stream water and later experience abdominal cramps with foul-smelling and greasy stools. Giardia lamblia infection can occur by ingesting as few as 10 eggs, resulting in asymptomatic cyst passage, self-limited diarrhea, or chronic diarrhea with associated malabsorption and weight loss, This infection is best diagnosed by which of the following?

Patients with E. histolytica have an asymptomatic carrier rate greater than 90%. Chronic disease (intermittent bloody diarrhea and abdominal pain from months to years) is often difficult to distinguish from inflammatory bowel disease. E. histolytica infection is best diagnosed by which of the following?

Many patients with Strongyloides low worm burden are asymptomatic. Initial infection occurs by skin penetration and a pulmonary migration occurs. Patients demonstrate dry cough, wheezing, low-grade fever, dyspnea, and hemoptysis. Treatment is available for parasite eradication. Which is the best method listed below for detecting Strongyloides larvae?

Ascaris lumbricoides are large worms that have a complex life cycle in human hosts involving the digestive system, bloodstream, heart and liver, pulmonary circulation, and back to the small intestine. Serious medical complications may occur in any of these sites making diagnosis critical. Ascaris is best observed in human specimens by which one of the following?

A butcher develops a questionable habit of eating various kinds of raw, ground meat over several years. He eventually starts suffering from fatigue and lymphadenopathy. In his extensive physical examination, intensely white focal retinal lesions with vitritis are observed. Chorioretinitis is diagnosed, even though an older laboratory test, the Sabin–Feldman dye test, is found positive. This patient is found to be infected with which of the following?

One week after eating bear meat, a fur trapper develops diarrhea, nausea, and vomiting. The next week, he experiences systemic symptoms of fever, myalgias, and malaise. His doctor notes periorbital edema and swollen eyelids, and laboratory tests report an eosinophilia. He is diagnosed with which of the following?

A newspaper correspondent is sent to St Petersburg, Russia, to cover political events occurring there. She drinks only bottled water except on a side trip to the countryside to visit an old monastery. Two weeks later and at home, she develops a chronic diarrhea where the stools are watery, greasy, and foul smelling. Which of the following is the most likely diagnosis?

A retired air force colonel has had abdominal pain for 2 years; he makes yearly freshwater fishing trips to Puerto Rico and often wades with bare feet into streams. Which of the following should be included in the differential diagnosis?

A teenager who works in a dog kennel after school for 2 years has had a skin rash, eosinophilia, and an enlarged liver and spleen. Which of the following is the most likely cause of this infection?

A young woman goes to her doctor with a variety of medical complaints. Her mucosal surfaces are tender, inflamed, eroded, and covered with a yellow discharge. For one problem, the laboratory reports the isolation of a pear-shaped protozoan with a jerky motility. This organism is observed in which of the following?

A hunter, successful in his first black bear hunt, takes the meat home to eat. After consuming meals including bear meat over several weeks, two family members develop a flu-like syndrome and mild diarrhea. Several weeks later, two others have fever, GI distress, eosinophilia, muscle pain, and periorbital edema. Which of the specimens listed below would most easily detect the organism responsible for the clinical presentations described?

A family of four goes on a vacation for 3 weeks to Central and South America. They consume the usual diets in all the areas they visit, including raw and pickled crustacean. Weeks later, two members produce brown sputum when coughing, hemoptysis, and eosinophilia, while the others are asymptomatic. A tissue-dwelling trematode causing this may be found in feces and which of the following?

A forest ranger who routinely drinks untreated stream water and develops minor, intermittent diarrhea, which becomes chronic. Laboratory examination of several stools fails to determine any specific organism. Her physician decides to use the Entero-Test to try to discover the agent causing the symptoms. Cysts of a protozoan adhere to a piece of nylon yarn coiled in a gelatin capsule, which is swallowed. These cysts are usually found in which of the following?

A person from Nantucket Island, Massachusetts, develops fever, fatigue, sweats, and arthralgia after hiking with friends in a forest. His physician finds evidence of tick bites that had not been noticed. A parasite resembling malaria that infects both animals and humans and is carried by the same tick that transmits B. burgdorferi (the Gram-negative spirochete that causes Lyme disease) would most likely be observed in which of the following?

A patient with AIDS returns from Haiti with acute diarrhea. The stool reveals an oval organism (8-9 μm in diameter) that is acid-fast and fluoresces blue under ultraviolet light. The most likely identification of this organism is which of the following?

A 64-year-old sheepherder from the farming region of central California is rushed to the emergency room in anaphylactic shock. The history, as told by the ambulance medic, is that the man was hit in the abdomen during a barroom brawl. Ultrasound reveals a large cyst mass in the liver. A cautious needle aspiration of the liver mass reveals “hydatid sand.” Which of the following is the most likely agent involved?

A tiny worm was passed in the stool of a 6-year-old child. The child reported perianal pruritus, especially at night. The worm measured 10 mm in length and had a pointed tail. The eggs recovered by “Scotch tape” method. What species does it represent?