Block 11 - Week 12 - Viral Hemorrhagic Fevers
- 1.A 38-year-old male UN peacekeeper returning from Liberia, western Africa, presents with fever, malaise, asthenia, cough, sore throat, abdominal pain, diarrhea, nausea, and vomiting. Later in the course of the disease, the patients presents with mucosal bleeding, conjunctival injection, face edema, rales, and hypotension. The patient is treated with ribavirin administered intravenously. Pre-immune serum from the patient is negative for hemorrhagic fever viruses, but serum obtained from the patient 15 days after resolution of the illness is positive for an enveloped, segmented (-) ssRNA virus. What is the reservoir host of the virus responsible for this patient’s disease?
- A.
Humans
- B.
Bats
- C.
Ticks
- D.
Rats
- E.
Mosquitoes
- 2.A patient returning from Uganda presents with abrupt onset of fever, weakness, diarrhea, nausea and vomiting, and a maculopapular rash. Pre-immune serum from the patient is negative for hemorrhagic fever viruses, but serum obtained from the patient 15 days after resolution of the illness is positive for an enveloped, (-) ssRNA filamentous virus. What is the reservoir host of the virus responsible for this patient’s disease?
- A.
Rats
- B.
Humans
- C.
Bats
- D.
Ticks
- E.
Mosquitoes
- 3.Which of the following viruses, known to be associated with viral hemorrhagic fevers, can induce an immune response, which may result in a more severe disease if the patient is subsequently infected with a heterologous strain of the same virus?
- A.
Yellow fever virus
- B.
Ebola virus
- C.
Dengue virus
- D.
Marburg virus
- 4.Your patient is a Native American living on the border between Arizona and Utah. He presented with alternating fever and chills, myalgia, nausea with vomiting and a marked petechial rash over his body. This is the third case you have seen recently from patients from the same Native American reservation. There is no apparent reason for these outbreaks, except that the weather has been even dryer than usual in this region and many mice and other rodents have been seen near human habitation looking for food. Which of the following viruses might you suspect is causing your patient’s condition?
- A.
Crimea-Congo Hemorrhagic virus
- B.
Hantavirus
- C.
Rift Valley virus
- D.
Dengue virus
- 5.On a Caribbean island, about 20 patients last year were hospitalized with fever, myalgia, and petechial skin rashes. Two of them died with shock. The outbreak was caused by dengue virus of serotype 2. Ten years earlier there had been an island outbreak of dengue caused by serotype 1. Why was last year’s disease so severe?
- A.
Low concentrations of cross-reacting antibodies from exposure to serotype 1 were not sufficient to neutralize virus of serotype 2
- B.
Antibodies against serotype 1 were present but did not cross-react with virus of serotype 2
- C.
Antibodies against serotype 1 cross-reacted with virus of serotype 2 to opsonize virus for greater uptake by macrophages
- D.
Antibodies against serotype 1 cross-reacted with virus of serotype 2 to block its phagocytosis by macrophages
- 6.Yellow fever virus differs from dengue virus in which way?
- A.
It is a flavivirus whereas dengue is a filovirus
- B.
It occurs in Asia whereas dengue is limited to South America and Africa
- C.
It is a naked RNA virus whereas dengue is an enveloped virus
- D.
It invades the liver whereas dengue is mainly in macrophages and blood
- 7.A 5-year-old girl in the Caribbean developed fever, fatigue, and headache that persisted for 5 days. As these symptoms were subsiding she noted a red rash on her trunk. She was taken to the family doctor, who described the rash as macular and blanching but some of the spots were petechial and non-blanching. The blood pressure fell to 80/55. She was hospitalized and given intravenous saline. After 3 days the blood pressure rose to 106/74, the rash faded, and she was discharged in improved condition. What are features of this disease?
- A.
It is caused by a Flavivirus and spread by Anopheles mosquitoes
- B.
Hemorrhage and shock can result from re-infection by a different serotype of the same virus
- C.
It is caused by Hantavirus and spread by Aedes mosquitoes
- D.
Antibodies against the virus provide immunity that is cross-protective against multiple serotypes of the same virus
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