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Zika and West Nile Virus Summary Update - Pfister
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Mosquito-borne diseases are those that are transmitted to people through the bite of an infected mosquito. These diseases include: Zika Virus, West Nile Virus (WNV), Dengue, Chikungunya, Malaria, Yellow Fever, and some forms of encephalitis. Currently, Zika and WNV receive most of the public and media attention in our country.
Zika virus is similar to Dengue, Yellow Fever, and West Nile and is primarily transmitted through mosquitoes and sex. As of September 7, 2016, there have been 2,964 cases of Zika reported in the United States and D.C., of which 671 of the cases were pregnant. There have also been 15,869 cases of Zika reported in U.S. Territories, of which 1,080 of the cases were pregnant. In the U.S. there have been 43 locally acquired mosquito-borne Zika cases reported, 2920 travel-associated Zika cases (24 were sexually transmitted) and 1 laboratory acquired Zika case. In the U.S., 7 people had Guillain-Barré syndrome and in U.S. Territories, 31 people had it. Sexually transmitted cases are not reported for U.S. Territories because with local transmission of Zika virus it is not possible to determine whether infection was a result of mosquitoes or sexual contact.
The Illinois Department of Public Health (IDPH) is currently reporting 60 confirmed cases of Zika virus disease statewide, compared to 17 in May. In Lake County, 138 suspect Zika cases have been investigated so far (15 of them are males), and almost all of them have been tested serologically. Seventy pregnant women had an ultrasound test and only one of those tests showed slight enlargement of the head, however, that case was ruled out as Zika. Of all serologically tested cases, five were confirmed with Zika (none pregnant), and four individuals were counted as Arbovirus Unspecified cases, due to increased Dengue titers.
In regard to WNV, the state of Illinois currently reports 15 human cases (compared to 77 total last year), 43 positive birds (primarily American Crow), 2021 mosquito pools (batches), and one horse. In Lake County, one human case has been reported in Ingleside compared to five total cases in the county last year. In addition, there have been 84 positive mosquito batches, which is above our 15-year average of 58. Increased positive pools tend to be associated with higher summer temperatures, which we had in 2016. We also have two WNV positive birds.
LCHD/CHC is coordinating with our vendor (Clarke) on mosquito abatement efforts in the County. Most of the municipalities and townships have contracts with Clarke to conduct abatement. Special attention is given to areas were WNV positive mosquitoes have been found. This often results in additional abatement efforts to reduce adult Culex mosquitoes which are the primary vector of WNV in Lake County. Mosquito activity may decrease as night temperatures drop, but residents should be vigilant and take precautions through September. Mosquito trapping efforts will continue until the first week of October.
In addition to the regular mosquito-abatement efforts, case finding and follow-up, and public and health care provider education, LCHD/CHC reached out to the Lake County Township Supervisors, the Municipal League and Township Highway Commissioners and provided education via Power Point, webinars and in-person presentations on the risk of mosquito-borne diseases and prevention efforts.
Suggested Motion
None, for information only.