A mother brings her 20-month-old son to your office. She was called by her day care center who reported he had vomited twice during the morning and had diarrhea as well. She noted he had a slight fever the past 2 days and had not been very hungry. The most likely cause of his illness is
A mother brings her 7-year-old son to your office and reports that about 10 days ago he had a flu-like disease with a minor fever. Three days ago he had a very red face which turned normal color when touched, and now he has a red rash on his arms and legs which also blanches to touch. She states he had all the normal childhood shots. The most likely infectious cause of his symptoms is
A kindergarten day care has reported that most of the children are experiencing severe sore throats. Upon further investigation, it has been observed that they also have low-grade fevers and vesicular lesions (some of which have developed into ulcers) on their tonsillar and pharyngeal mucosa. What is the most probable cause of these symptoms?
A Brazilian who left poverty and moved to Los Angeles 12 years ago has died suddenly of heart failure. Autopsy showed cardiomyopathy due to Chagas’ disease. Which vector transferred the trypanosomes?
A full-term 5-day-old neonate is brought in with a purulent conjunctivitis which the parents noticed earlier today. On Gram stain of the purulent exudate, no bacteria are seen. Which of the following bacteria is most likely the cause of the conjunctivitis?
A healthy 6-year-old boy who has not traveled outside the United States is brought in by his parents in June with signs of meningitis. No bacteria are seen in the Gram stain of the CSF, and no bacterial capsule material is present as determined by a series of latex particle agglutination tests standard to the diagnosis of meningitis. The CSF glucose level is slightly low, protein is near normal, and white cell count is less than 500 cells/microL, mainly lymphocytes. What is the most likely causative agent?
A 9-year-old boy presents with an itchy scalp with the underlying hair becoming lighter. The patch has expanded to 2 inches. What should you expect to see in a KOH digested mount of skin scrapings taken at the infected margin of a lesion from this patient with tinea capitis?
A 91-year-old male presents with a cough of several months duration. He has been coughing up brownish stuff The man is 5’6€³ tall and his weight is down from 150 to 140 lbs., having lost 10 lbs. in the past 2 months without trying. His tuberculin skin test has been greater than 10 mm the three times you have tested him in the 25 years he has been your patient. The chest radiograph is consistent with reactivation TB. You order Mycobacterium tuberculosis testing and susceptibilities and start him on standard therapy. Luminescent real time PCR confirms M. tuberculosis. What has been the standard medium used to grow M. tuberculosis and what is the standard clue to TB in examination cases?
A bacteriophage that is not inactivated by proteases is referred to as a
A biology graduate student who recently visited a tropical region of Africa presents with new visual impairment and the sensation that something is moving in her eye. She tells you that she is concerned because she had been warned about eye disease transmitted by black flies. When in Africa, she was in a river area, and despite her best efforts she received a lot of black fly bites. She also has some subcutaneous nodules. If her infection was acquired by black fly bite, what is the most likely causative agent?