West Nile virus in Vermont

Avoiding mosquito-borne diseases like West Nile virus is a primary motivation for mosquito control. Since it was first confirmed in the US in 1999, West Nile virus has infected more than 46,000 people in the US and more than 2,000 people have died. Mosquitoes infected with West Nile virus have been found in every Vermont county in past years, so this threat should not be ignored. However, between 1999 and 2016, only 12 cases of West Nile virus were reported in people in Vermont (Figure 1).

Figure 1. Total number of cases (mild plus neuroinvasive) of West Nile virus in US states (1999-2016) ordered from most (left) to least (right). Source.

New England has a comparatively low per capita incidence of West Nile virus disease. Between 1999 and 2016, the chance each year of developing a serious disease from West Nile virus was zero in most Vermont counties, and less than 1 in 200,000 in Addison County (Figure 2).

Figure 2. Average annual incidence (1999-2016) of neuroinvasive disease caused by West Nile virus by county. Source.

These results suggest that monitoring the presence of West Nile virus in Vermont is important, but alarming rhetoric about the disease risk in Vermont might not be justified.


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