Question
You are the epidemiologist recruited to investigate the recent outbreak of hantavirus in Yosemite National Park. The following information is from the CDC website [with slight modifications]. Use this information to fill in the missing labels in the graph below to show the following phases specific to Hantavirus Pulmonary Syndrome (HPS): causal action, biologic onset, detectable by screening, symptoms develop, death.
In the United States, deer mice are the reservoir of the virus. The rodents shed the virus in their urine, droppings, and saliva. The virus is mainly transmitted to people when they breathe in air contaminated with the virus.
Diagnosing HPS in an individual who has only been infected a few days is difficult, because early symptoms such as fever, muscle aches, and fatigue are easily confused with influenza. However, if the individual is experiencing fever and fatigue and has a history of potential rural rodent exposure, together with shortness of breath, that would be strongly suggestive of HPS. A positive serological test result, evidence of viral antigen in tissue by immunohistochemistry, or the presence of amplifiable viral RNA sequences in blood or tissue, with compatible history of HPS, is considered diagnostic for HPS. The test for viral antigen can confirm exposure to hantavirus within 24 hours, but is itself insufficient to diagnose HPS.
Through December 31, 2011, a total of 587 cases of Hantavirus Pulmonary Syndrome have been reported in the United States. Of these, 556 cases occurred from 1993-onward, following the initial identification of HPS, whereas 31 cases were retrospectively identified. The case fatality rate from 1993-2011 was thirty-six percent.
You are the epidemiologist recruited to investigate the recent outbreak of hantavirus in Yosemite National Park. The following information is from the CDC website [with slight modifications]. Use this information to fill in the missing labels in the graph below to show the following phases specific to Hantavirus Pulmonary Syndrome (HPS): causal action, biologic onset, detectable by screening, symptoms develop, death.
In the United States, deer mice are the reservoir of the virus. The rodents shed the virus in their urine, droppings, and saliva. The virus is mainly transmitted to people when they breathe in air contaminated with the virus.
Diagnosing HPS in an individual who has only been infected a few days is difficult, because early symptoms such as fever, muscle aches, and fatigue are easily confused with influenza. However, if the individual is experiencing fever and fatigue and has a history of potential rural rodent exposure, together with shortness of breath, that would be strongly suggestive of HPS. A positive serological test result, evidence of viral antigen in tissue by immunohistochemistry, or the presence of amplifiable viral RNA sequences in blood or tissue, with compatible history of HPS, is considered diagnostic for HPS. The test for viral antigen can confirm exposure to hantavirus within 24 hours, but is itself insufficient to diagnose HPS.
Through December 31, 2011, a total of 587 cases of Hantavirus Pulmonary Syndrome have been reported in the United States. Of these, 556 cases occurred from 1993-onward, following the initial identification of HPS, whereas 31 cases were retrospectively identified. The case fatality rate from 1993-2011 was thirty-six percent.
Source: PB HLTH 250B 2014 Practice Problems Exam 1
