This week, the Louisiana Department of Health has confirmed three additional cases of Zika virus. This brings the total to 26 cases of travel-associated Zika confirmed in Louisiana. There are no known locally transmitted cases here. Local transmission occurs when an infected mosquito in the area bites another person in the area and transmits the virus. This local transmission is much more likely in the parishes around Lake Pontchartrain than other areas of the state.

National and state Zika virus case counts compiled by the CDC can be found here. Once a travel-related case is identified, public health officials and local mosquito control agencies are notified to take action to minimize the potential for local spread. 

14 West Nile Virus Cases Confirmed

Louisiana’s first cases of West Nile virus of this year have also been confirmed. Dr. Raoult Ratard, state epidemiologist said none of these cases are related to the recent flooding event.

“These West Nile infections all occurred before the recent flooding. I do not expect that we will see as many cases as we’ve seen in past as we are having a late start to the time of the year when we normally begin to see people getting West Nile virus infections,” Ratard said.

West Nile case counts are compiled by the CDC here.

South Louisiana Floods and Mosquito-Borne Diseases

Dr. Frank Welch, medical director of community preparedness at the Louisiana Department of Health, said the recent floods increase the risk of West Nile virus in areas that were flooded.

Welch said residents should see an immediate reduction of mosquitoes because the floods drowned most of the mosquito populations. But, he added that as the waters reside, mosquitoes will return and their numbers will increase due to standing water left from the flood.

“We can expect to see an increase in many types of mosquitoes after flooding, and also in the mosquitoes that carry the West Nile virus" said Welch. “The mosquitoes that can carry Zika virus are located in the region in and around New Orleans which were not impacted by the floods. However, there has been a lot of rain in the New Orleans area, which does foster the environment where the Zika virus mosquito thrives”.

"CDC is working closely with state and local officials in Louisiana to monitor the situation,” said Dr. Ben Beard, chief of CDC’s Bacterial Diseases Branch. “Though it is possible that Louisiana may see an increase in the number of cases of West Nile virus as a result of the flooding, studies show that flooding does not typically result in increased risk.”

Prevention: Avoiding a Zika Infection

Zika virus is of greatest threat to pregnant women, as their child may be at risk for certain severe birth defects as a result of infection. Pregnant women and women trying to get pregnant should avoid travel to areas with Zika transmission. The CDC has a list of travel notices for these areas here. Because Zika can spread through sexual activity, pregnant women should have their partners use a condom correctly every time or abstain from sex. 

All travelers to areas where Zika virus is active should be aware and take the following steps to protect themselves from mosquito bites:

  • Use an EPA-approved insect repellent.
  • Wear light-colored, long sleeves and pants.
  • Sleep under a mosquito net if you are outdoors or in an area without door and window screens.

The same precautions apply at home, and people should also make sure their house is mosquito-proof by ensuring their windows and doors have intact screens. Once a week or after every rainfall, empty standing water from any containers around your home, especially small containers. 

Weekly Mosquito Reporting

For more information about preventing Zika virus, visit For weekly arboviral reports with more detailed information about West Nile and Zika infections in Louisiana, click here.

The Louisiana Department of Health strives to protect and promote health statewide and to ensure access to medical, preventive and rehabilitative services for all state residents. To learn more about LDH, visit For up-to-date health information, news and emergency updates, follow LDH's Twitter account and Facebook.