Short-Lived Mosquitoes

** FILE ** This undated handout file photo provided by the Agriculture Department shows an aedes aegypti mosquito on human skin. Old mosquitoes usually spread disease, so Australian researchers figured out a way to make the pests die younger - naturally, not poisoned. Scientists have been racing to genetically engineer mosquitoes to become resistant to diseases like malaria and dengue fever that plague millions around the world, as an alternative to mass spraying of insecticides. (AP Photo/USDA, File)

Three horses tested positive recently for a potentially deadly mosquito-borne illness in southern Louisiana, raising concerns from state officials about the increasing number of mosquitoes due to recent warm and wet weather.

The Louisiana Department of Agriculture and Forestry said Tuesday a horse in Iberville Parish and two in Lafourche Parish recently tested positive for eastern equine encephalitis, a potentially deadly illness spread from mosquitoes that can sicken humans and other animals too.

Officials say the recent bout of humid and hot weather throughout the state has led to more mosquitoes in areas and has increased the risk of animals contracting diseases they spread.

“Mosquitoes are out in force right now,” Agriculture and Forestry Director Mike Strain said in a statement Tuesday. “The hot and wet conditions exacerbated by storms such as Hurricane Laura increase the number of mosquitoes that could be carrying diseases.”

He urged horse owners to vaccinate their animals to prevent them from getting sick.

The encephalitis, commonly referred to as EEE, is transmitted from mosquitoes to other animals, including those in the horse family, such as donkeys and mules.

In horses, symptoms often include fever, loss of appetite, weakness, loss of coordination and circling, all of which can sometimes lead to death. In rare cases, humans can develop similar symptoms that are also life-threatening and they are less protected because no vaccine exists for people, according to the U.S. Centers for Disease Control and Infection. 

Only about 5% of people who contract EEE get sick, but children under 13 and older adults appear to be more vulnerable to the virus. 

Birds carry the illness and pass it to mosquitoes who go on to bite other animals and spread the disease, similar to other ailments like West Nile virus, dengue fever and malaria.

The latest CDC figures show 38 people contracted EEE in 2019, just two fewer than the past seven years combined. Two human cases have been confirmed in Louisiana since 2010, with the highest concentration of cases in Upper Midwestern and Northeastern states.

Several southwestern Louisiana parishes started aerial spraying for mosquitoes to stamp out mosquito hotbeds in marshes and other areas following Hurricane Laura's landfall, the LSU AgCenter said last week.

The action followed reports of thick clouds of mosquitoes in hurricane-stricken parishes and numerous livestock deaths caused by the insects’ bites.

Agriculture and Forestry as well as numerous local mosquito abatement agencies say people can reduce the risk of contracting mosquito-borne illness by dumping out standing pools of water where the insects breed. People should also use mosquito repellents, wear pants and long sleeves, and avoid the outdoors at dusk and dawn when mosquitoes are most active.


Email Youssef Rddad at yrddad@theadvocate.com, and follow him on Twitter @youssefrddad