Mississippi Reports Additional Mosquito-Borne Cases In Humans

Ruzanna Harutyunyan's picture

Today, the Mississippi State Department of Health (MSDH) reports three new human cases of West Nile virus (WNV) for 2008, bringing the state's total number of WNV cases to 99 with three deaths. The new cases are in Hinds, Jackson and Leflore counties. The agency also reports one case of Jamestown Canyon virus (JCV) in Lamar County. MSDH reports both confirmed and probable cases to the public.

Since March 2008, WNV cases have been reported in Calhoun, Clarke, Forrest (4), George (2), Grenada, Harrison (2), Hinds (22), Jackson, Jasper (3), Jones (15), Lamar (2), Lawrence, Leake (3), Leflore (5), Lincoln (4), Madison (7), Marion (3), Monroe (2), Neshoba (7), Panola, Pearl River, Rankin (3), Scott (4), Simpson, Sunflower, Washington and Wayne counties. Deaths have been reported in Forrest, Hinds and Leflore counties. Six cases of LaCrosse Encephalitis (LAC) have been reported in Adams, Amite, Harrison, Hinds, Madison and Yazoo counties with one case of JCV in Lamar County. Six cases of Eastern Equine Encephalitis and two cases of WNV have been reported in horses.

Jamestown Canyon virus cases are occasionally reported in Mississippi; the most recent case was reported in 2006. Symptoms of JCV infection vary from no symptoms to a mild fever to, in extreme cases, encephalitis.


The Jamestown Canyon virus circulates among deer, horses, and other wild and domestic large mammals by way of mosquito bites. It is also transmitted to humans through mosquito bites. The virus is relatively rare, but occasionally may be carried by several Mississippi mosquitoes, including the Tree Hole mosquito, Ochlerotatus triseriatus. This is the same mosquito that carries LAC, which breeds around homes in tree holes, old cans, tires and other artificial containers.

The MSDH conducts statewide mosquito testing with its most intensive surveillance during the peak WNV mosquito reproduction months of July, August and September. It is important to remember that mosquito-borne diseases, including WNV, occur statewide and throughout the year.

The MSDH encourages all Mississippians to take the following precautions to reduce the risk of contracting WNV, JCV and other mosquito-borne illnesses: remove sources of standing water; avoid mosquito-prone areas, especially between dusk and dawn when mosquitoes are most active; wear protective clothing (such as long-sleeved shirts and pants) when in mosquito-prone areas; and apply a DEET-based mosquito repellent according to the manufacturer's directions.

Symptoms of WNV infection are often mild and may include fever, headache, nausea, vomiting, a rash, muscle weakness or swollen lymph nodes. In a small number of cases, infection can result in encephalitis or meningitis, which can lead to paralysis, coma and possibly death.