Exam 11: Travelers Diarrhea: Identifying the Causative Agent

IgA is largely responsible for protection of the respiratory and intestinal mucosal tract. Effective protection is dependent on the action of a secretory piece which

Which of the following is the most sensitive type of serologic test?

Bacterial surface polysaccharide plays a critical role in

A 10-month-old child presents with a temperature of 39.8°C (103.6°F) and lethargy. Brudzinski's and Kernig's signs are both present. Gram stain of sediment from CSF showed Gram-negative rods. What part of the routine health care could have prevented this disease?

A neonate develops meningitis at 7 days of age. Her mother is 16 years of age, single, has had multiple sexual partners without barrier protection, and lives in the United States. The baby was born 23 hours after the mother's amniotic sac ruptured. What is the most likely causative agent?

A 3-year-old child develops acute glomerulonephritis following impetigo. The bacterium is a catalase-negative, Gram-positive coccus that has M12 surface protein. What is the most likely causative agent?

A 6-month-old infant is brought to the emergency department (ED) having woken up from a nap with a weak cry, ptosis, unreactive pupils, and the inability to lift her arms. She has had routine well-baby care. There is no sign of physical abuse or rash, and she is afebrile. The physician puts the child on a respiration monitor and calls the infectious disease consultant. What is most likely causing the problem?

In question 5, the patient's medical records indicate she was vaccinated 2 years ago for hepatitis B. In light of this, how do you interpret the HBV serological findings?

One advantage of live, attenuated vaccines is

An outbreak of pneumonia occurs in a pediatric intensive care facility. A negative single-stranded RNA virus lacking hemagglutinating and neuraminidase activity is isolated. The virus is a

A 7-year-old develops watery diarrhea, which becomes bloody, frightening him. He is afebrile but becoming very ill. Macroscopic examination of the feces shows no areas of pus; microscopically, there was no excess of PMNs over that expected from peripheral blood. If his disease is a result of a trip to a Wisconsin dairy farm and petting cattle, what is most likely causing the bleeding?

A 27-year-old worker at a day care center has recently been feeling tired, has a slight fever, and has felt nauseated and vomited several times. Yesterday, she had abdominal pain and chills, and today she voided dark urine. Lab tests for serum enzymes indicated elevated AST and ALT. The genetic material of the virus most likely to cause her symptoms is

A 17-year-old develops Neisseria meningitidis meningitis. What was the first event?

A patient with hay fever switches from IgG formation to IgE production via

What is the mechanism of action of the toxin?

If one were to create a single antigen vaccine to have prevented the outbreak and for use as a vaccine in women prior to pregnancy, what viral molecule would be most likely to lead to the production of successful neutralizing antibodies?

A 26-year-old man who is heterozygous for Rh factor marries an Rh- woman. What would genetic theory predict about their offspring?

A 22-year-old female student complains of excessive fatigue for the past 2 months. Polyarthralgia and vasculitis is noted on examination. Lab tests reveal multiple autoantibodies including antidouble-stranded DNA. The most logical diagnosis is

An 18-year-old Iowan dirt bike racer, who raced for the first time in the desert southwest 3 weeks ago, presents in September with cough, malaise, low-grade fever, myalgias, and chest pain. Rales are heard and respiratory infiltrates are noted on radiograph. Sputum stained with calcofluor white and viewed on an ultraviolet microscope shows large blue-white fluorescing spherical structures (with a wall) and with numerous small round cells inside. What is the most likely causative agent?

A recent Asian immigrant was found to be positive for the tuberculin skin test. The positive result most likely can be attributed to