West Nile Fever
Infectious Disease Case Study Assignment
After reviewing this case study, address these questions:
1.
West Nile fever is caused by the West Nile virus. Describe the emergence of novel disease in the Western hemisphere. Provide some examples of sources of infection for novel diseases, including the mode of transmission for WNV. Why is this a concern?
In late August of 1999, an unusual cluster of encephalitis cases was reported to NYC’s
Department of Health. Laboratory sequencing of virus isolated from brain tissue of birds identified WNV lineage. Retesting of clinically ill human cases and testing of horses presenting with CNS disease in Long Island, NY revealed WNV as the cause of disease (Asnis, Conetta,
Teixeira, Waldman, Sampson, 2000) . A total of 62 human cases of WNV were identified during
this …show more content…
By extrapolation from a householdbased study it was estimated that the NYC WNV outbreak in 1999 caused around 8 200 asymptomatic infections, causing disease in approximately 1 700 individuals. This was the first evidence of WNV activity in the Western Hemisphere (CDC, 1999).
During the first years of circulation in North America, WNV persistence over the winter months was attributed to continued transmission during winter, overwintering of the virus in mosquitoes and vertical WNV transmission from infected females to their offspring (Reisen, Fang, Lothrop,
Martinez, Wilson, Oconnor, 2006). WNV infection of migratory birds was suggested to contribute to the fast dissemination of WNV in North and South America. Nevertheless, WNV amplified and extended its distribution across the lower 48 continental states and has been declared endemic within 10 years of its introduction (Bernard, Kramer, 2001).
West Nile Virus is a concern because in the most rare and extreme cases it can cause a condition called encephalitis, which is irritation and swelling of the brain.
After reviewing this case study, address these questions:
1.
West Nile fever is caused by the West Nile virus. Describe the emergence of novel disease in the Western hemisphere. Provide some examples of sources of infection for novel diseases, including the mode of transmission for WNV. Why is this a concern?
In late August of 1999, an unusual cluster of encephalitis cases was reported to NYC’s
Department of Health. Laboratory sequencing of virus isolated from brain tissue of birds identified WNV lineage. Retesting of clinically ill human cases and testing of horses presenting with CNS disease in Long Island, NY revealed WNV as the cause of disease (Asnis, Conetta,
Teixeira, Waldman, Sampson, 2000) . A total of 62 human cases of WNV were identified during
this …show more content…
By extrapolation from a householdbased study it was estimated that the NYC WNV outbreak in 1999 caused around 8 200 asymptomatic infections, causing disease in approximately 1 700 individuals. This was the first evidence of WNV activity in the Western Hemisphere (CDC, 1999).
During the first years of circulation in North America, WNV persistence over the winter months was attributed to continued transmission during winter, overwintering of the virus in mosquitoes and vertical WNV transmission from infected females to their offspring (Reisen, Fang, Lothrop,
Martinez, Wilson, Oconnor, 2006). WNV infection of migratory birds was suggested to contribute to the fast dissemination of WNV in North and South America. Nevertheless, WNV amplified and extended its distribution across the lower 48 continental states and has been declared endemic within 10 years of its introduction (Bernard, Kramer, 2001).
West Nile Virus is a concern because in the most rare and extreme cases it can cause a condition called encephalitis, which is irritation and swelling of the brain.