The recent announcements of the first locally-transmitted cases of Zika virus on the mainland U.S. (in south Florida) has the media and the public in a frenzy and raising concern about spending time outdoors and the need to control mosquitoes.
As of August 3rd, the CDC had reported 1819 cases of Zika virus across the U.S., representing a 10% increase in cases over last week. New York and Florida continued to lead the nation with 491 and 322 cases, respectively (nearly 45% of all U.S. cases). North Carolina saw a significant (42%) jump with 30 reported cases which placed it at #13. Florida has subsequently reported several more local cases and Pennsylvania has the only recorded accidental laboratory exposure.
With the exception of Florida’s local cases, ALL of the remaining cases (in NC and nationally) were travel-related – either people who became infected while outside the U.S. or who had sexual contact with someone who had become infected while outside the U.S. The CDC was investigating possible local transmissions in one case in Utah that may have been care-related. Compare these stats with the Commonwealth of Puerto Rico which has over 5400 locally-transmitted cases of Zika virus.
This isn’t meant to downplay the significance of the disease. The recent attention to the website with the “Zika Hot Spots” map showing coastal North Carolina as a potential hot spot has caused some misunderstanding. If you read their disclaimer, they mention that the information is based solely on weather-related data, not on actual surveys and is not meant to convey that either the primary mosquito vector (Aedes aegypti) or the Zika virus are present in these areas. It’s important to understand that North Carolina is not south Florida (that’s not a lead-in to “snow bird” jokes). Seeing mosquitoes in your yard now (just as you likely have seen every summer!) does not mean you’re at greater risk of getting Zika virus. There is no need to collect mosquitoes and try to have them tested for Zika.
Reducing mosquito populations helps reduce both the nuisance biting aspect of mosquitoes as well as the risk of exposure to other mosquito-borne diseases. All of the attention has been on Zika, but we also have “resident” diseases such as West Nile virus (WNV), eastern equine encephalitis (EEE) and LaCrosse encephalitis (LAC) which show up in relatively low numbers in our state nearly every year. This fact is not intended to send people into a panic either. In the ten year period of 2003-2012, NC had 6 human cases of EEE and 43 cases of WNV, and 187 cases of LAC which points to a low likelihood of a severe problem occurring. On July 2nd of this year, the NCDA&CS reported the first fatal case of EEE in a horse in Pitt County (eastern NC). With the recent rains and still several more weeks to our long hot summer, we’re likely to see additional cases in horses and possibly some human cases as well.
Mosquito control doesn’t start with spraying pesticides in your yard. It begins by assessing your yard, your neighbors’ yards and your community for conditions that may favor mosquitoes and then figure out what you can to about. For advice on what to look for and what do in turns of “source reduction”, check out https://ncurbanpests.wordpress.ncsu.edu/feature/2016/mosquito-control-more-than-pesticides/.