Test 4 Practice Questions

A 17 y/o boy presented with a 10-day history of joint pain, fever, and headache. On examination at presentation he was noted to have a characteristic rash on both arms (image). During a walk in a forest 3 weeks before presentation, he recalls being bitten by numerous ticks, which were removed several hours later. Most likely cause is what?

A 17 y/o boy presented with a 10-day history of joint pain, fever, and headache. On examination at presentation he was noted to have a characteristic rash on both arms (image). During a walk in a forest 3 weeks before presentation, he recalls being bitten by numerous ticks, which were removed several hours later. Most likely cause is what?

An otherwise healthy 63 y/o man from rural Tunisia presented with a 1 month history of ulcerated skin lesions on the limbs (including a lesion on the left ankle (image)). Optical examination of a skin smear after Giemsa staining revealed amastigote forms of the parasite within infiltrating macrophages (image). The patient was treated with an intramuscular antimoniate and made full recovery. Most likely cause is what?

A 42 y/o man with a history of subcutaneous black tar heroin use presented to the hospital with slurred speech, diplopia (double vision), and dysphagia (difficulty swallowing). The physical exam showed bilateral ptosis (droopy eyelids), a sluggish pupillary response to light, and multiple skin abscesses on his arms and legs (images). Gram stain of the abscesses isolated an organism that grows exclusively under anaerobic conditions (image). Most likely cause of patient’s condition is what?

A female infant born at 26 weeks was transferred to the neonatal ICU. Her treatment included assisted ventilation, IV fluids, and broad-spectrum antibiotics. On the 5th postnatal day, the infant became clinically unstable, and a review of her peripheral blood smear showed the presence of a dimorphic organism. Despite appropriate clinical management, the infant died on the 12th day of her life. Most likely cause of her infection is what?

A 69 y/o man presented to the hospital complaining of progressively more severe headaches over several weeks, and sudden persistent hearing loss. Exam of the CSF showed the presence of numerous leukocytes and budding yeast cells (image). An India-ink preparation of the fresh CSF revealed the mucinous capsule of the organism as a translucent halo surrounding the budding yeast. Most likely cause is what?

A 43 y/o HIV + female presents to the clinic with a productive cough, fever, and general fatigue. Acid-fast staining of a sputum sample reveals numerous small bacilli (image). Chest X-ray reveals a cavitary lesion within the upper right lobe and generalized interstitial infiltrates throughout both lungs (image). PPD test shows an induration that measures >20 mm. Most likely cause is what?

A 35 y/o male with a history of chronic IV drug use presented to the ED with right upper limb pain and swelling. On clinical exam severe edema of the upper limb, erythema, blistering of the arm and crepitus over the shoulder and arm was noted (Image). An X-ray of the affected limb revealed gas within the soft tissues. The patient was started on broad-spectrum antibiotics and underwent arm and forearm fasciotomy to remove necrotic tissues. Cultures of tissue specimens obtained intraoperatively revealed the presence of anaerobic, gram + bacillus. Most likely cause of this infection is what?

A 44 y/o man was admitted to University Hospital with fevers and chills. Fever episodes occurred every 48 hours, with high peaks followed by abrupt resolution. He recently returned from Pakistan where he spent two months visiting friends and relatives. On further examination, he was found to have jaundice, tachycardia and hepatosplenomegaly. His peripheral blood smear is shown. Most appropriate conclusions are?

Image illustrates an example of inflammation of the eye associated with the leading preventable cause of blindness in the world. Amongst the causes for the loss of sight is the long-term mechanical abrasion of the cornea. This disease is called

A 28 y/o woman presents with a 12-day history of abdominal pain accompanied by bloody diarrhea with thick mucus. Her medical history reveals she recently returned from an extended vacation in South America where she often consumed food prepared by street vendors. Stool examination for O & P (ova and parasites) reveals these organisms (image). Colon biopsy identified characteristic flask-shaped lesions (image). Most likely cause is what?

A 14 y/o girl presented at the clinic with high fever (40.5 C), headache, malaise, and general fatigue. On closer exam, the physician observes yellowing of the sclera consistent with jaundice. Her father reported that they had recently returned from a camping vacation in Martha’s Vineyard where they had been bitten repeatedly by deer ticks. A thin blood smear revealed characteristic “Maltese cross” formations within a small subset of RBCs. Most likely diagnosis is what?

A 26 y/o female presents at the hospital complaining of dysuria and a yellow-green frothy discharge accompanied by pruritis. Upon examination the physician observes a classic “strawberry” cervix presentation characterized by punctate hemorrhagic lesions. Giemsa stain of a pap smear and the vaginal discharge was diagnostic for the infecting organism. Cause of patient’s condition

A recent outbreak if an STD involved over 90 men who has sex with other men. Symptoms included inguinal lymphadenopathy (image), painful genital ulcers and bloody proctitis with mucopurulent discharge and constipation. Many of these patients were concurrently infected with other STD-agents, including HIV, and reported engaging in unprotected anal intercourse. The diagnosis in the outbreak was confirmed by a PCR test, with revealed genotype L2 of what?

A 7 y/o girl is brought into the clinic complaining of fever, headache, muscle pains, and conjunctival injection (red eyes). On physical exam the physician noted a macular rash on her lower extremeties (Image). Microscopic examination of a blood sample revealed characteristic intracytoplasmic inclusion bodies within the monocytes (iamge). Most likely infectious agent is?

A pig farmer presents at the local hospital complaining of severe diarrhea, abdominal pain and weight loss. We mount of a stool sample reveals the following highly ciliated organism (image). The farmer is most likely infected with what?

A 40 y/o man who has been recently diagnosed with HIV, develops a generalized rash (images) accompanied by fever, malaise and bloody diarrhea. His peripheral blood smear and bone marrow aspirate are shown in (images). Blood culture at room temperature grows organisms producing hyphae. Most likely cause is what?

With many infectious diseases, more severe condition will often develop in individuals who are immunocompromised or immunosuppressed. OF the pathogens discussed in class, which is most likely to be responsible for the benign tumors observed in the picture?

A 46 y/o male veterinarian who specializes in exotic birds (iamge) was admitted to the hospital complaining of increasing weakness, generalized muscle pains, fever,chills, and night sweats for the previous five days. For the last 2 days he had a dry cough, anorexia, and a constant ache in his lower right back. Chest X-ray showed extensive infiltration in both lungs (image). Blood and sputum cultures were negative on conventional bacteriologic media. A presumptive diagnosis of bacterial pneumonia was made, and the patient showed improvement following a course of erythromycin. Exam of paired serum samples revealed a 16-fold rise in antibiotics against an intracellular pathogen. What was the most likely cause of the patient’s condition?

Which of the following genera has no detectable peptidoglycan layer (by techniques such as electron microscopy), yet is sensitive to inhibitors of peptidoglycan synthesis and contains the genes for the proteins necessary to make peptidoglycan?

The life cycle of Plasmodium falciparum comprises an exogenous sexual phase with multiplication in certain Anopheles mosquitoes and an endogenous asexual phase with multiplication in the vertebrate host. In strict biological terms the mosquito is considered what?

The human GI system is the site for many of the organisms we have considered. What is NOT found in the human intestine?

Which of the following diseases can progress to a stage where treatment-resistant arthritis develops, that is believed to result from an auto-immune like response due to similarity between a pathogen surface protein and a human protein?

Which of the following is a correct pairing of parasite and microscopic structure?

A 9-year-old girl presented to her local clinic in LA with a slight fever, dry cough, and myalgia. Chest X-ray showed a widened mediastinum and extensive diffuse infiltrates. QuantiFeron test was negative. A blood smear revealed numerous macrophages containing yeast cells. Patient history revealed she has recently returned from visiting her grandparents in central Missouri where she spent several hours in an abandoned chicken coop playing with newborn puppies. What is the most likely cause?

Which state typically has the highest number of cases of Rocky Mountain Spotted Fever each year?

Giardia lamblia typically results in a self-limiting diarrheal disease 1-2 weeks after exposure to contaminated water or foodstuffs. Which of the following animals is known to be a non-human reservoir for this parasite?

A 43-year-old woman presents to University Hospital complaining of gastrointestinal discomfort associated with large volume, watery diarrhea. Acid fast staining of a concentrated stool sample revealed the presence of tiny parasitic organisms. What is the most likely cause?

Which of the following species have been recently assigned to the genus Chlamydophila?

Which of the following diseases can be contracted as a water-borne infection resulting from drinking of water contaminated with rodent urine?

Which of the following enzymatic reactions may result in urogenital tract inflammation during a bacterial infection?

The Nagler test is used to identify which species?

The basis of the Nagler test is the neautralization/inhibition of the activity of which of the following?

A 25 year old man presents with moist erythematous lesions noted as condyloma lata. The rapid plasma regain test is performed. This is an indirect test and detects antibodies to which of the following?

A 37 year old HIV positive female presents at University Hospital complaining of acute onset of fever, headache, confusion, and seizure. Medical history reveals the patient recently consumed raw vegetables, obtained from her garden frequenced by her pet cats. What organism is most likely responsible?

A female student reports to Student Health at the start of the Fall semester complaining of fever, chills, severe headaches and loss of consciousness. The student reports that she recently returned from Africa where she was working as a volunteer teacher at a district school. Cerebral malaria is suspected but initial blood smear testing fails to identify the parasite in the sample. What is the most likely explanation?

The activity of the following toxins is/are produced following spore germination of a pathogen and results in diarrhea and damage to the intestinal mucosa that may result in pseudomembranous colitis?

Which of the following bacteria would be expected to LACK the enzymes superoxide dismutase and catalase?

The most likely lifestyle of organisms lacking superoxide dismutase and catalase is what?

An army veteran who recently completed his second tour of Iraq presents at the VA hospital with a large, painless lesion with characteristic “volcano” appearance on his left arm. What is the most likely cause?