Texas: West Nile Cases Rising

Source:  Texas: West Nile Cases Rising    Tag:  west nile virus canada



Credit DVBID

# 6460



In most places across the country the joys of summer are offset just a little bit by the seasonal surge in our mosquito population. And as often happens this time of year, we start to see small outbreaks of mosquito-borne illnesses.


One of the areas being hit hard right now is Dallas County, Texas which has recorded – as of last Friday – 82 human cases of West Nile Virus (WNV) infection this year.


The Dallas County Dept. of Health and Human Services announced the third local fatality from the virus late last week.


The latest information on positive cases, and areas with infected mosquitoes, can be found in the DCHHS West Nile Watch.



Fortunately, about 80% of those infected with WNV experience only mild, or sub-clinical symptoms. Most of the rest may experience a brief febrile illness (West Nile Fever).


A very small percentage (perhaps 1%) may develop WNV neuroinvasive disease (WNND), a form of encephalitis that can sometimes prove fatal. Those over the age of 50 appear to be the most vulnerable to the most serious form of the illness.



The West Nile Virus (WNV) is a relative newcomer to North America. It suddenly appeared in New York City in 1999, and over the next few years spread rapidly across the United States.


From the USGS Factsheet on West Nile Virus



Exactly how the virus was imported into the United States remains a mystery, although inter-hemispheric migration bird migration, birds carried by tropical storms, legal or illegal importation of birds from countries where the virus is endemic, or even infected mosquitoes hitching a ride on an international flight have been suggested as possibilities.


But no matter how it arrived, it flourished and spread. By 2005, the West Nile Virus had spread across all 48 contiguous states and had reached into Canada.



The natural reservoir for the West Nile Virus are birds. The virus is spread by mosquitoes that take a blood meal from an infected bird, and then go on to bite another bird, human, or other warm blooded animal.






On Friday the Texas Department of Health & Human Services issued this press release on the high number of cases already seen in the state.


DSHS Urges Precautions to Reduce West Nile Exposure

News Release
July 27, 2012

The Texas Department of State Health Services is urging people to take precautions to reduce the risk of contracting West Nile virus, a mosquito borne illness. People should use insect repellent when outdoors and avoid going outside at dusk and dawn.


There has been a higher than usual number of human West Nile cases in Texas this year due to the warm winter and recent rains, particularly in the North Texas region. Statewide there have been 111 human West Nile virus cases and one death reported to DSHS this year. Of those, 71 were West Nile neuroinvasive disease cases, and 40 were West Nile fever cases. Approximately 80 percent of the cases reside in Dallas, Collin, Tarrant and Denton counties.


Over the past 10 years, 49 cases on average were reported to DSHS by this time each year, ranging from a low of 3 cases in 2011 to a high of 171 cases in 2006.

(Continue . . . )



While WNV isn’t the only mosquito-borne disease to be concerned with in the United States, a quick look at the USGS’ DISEASE MAPs show that – right now at least – West Nile is the most active arbovirus reported across the nation.





Although the overall risk of contracting a mosquito-borne illness the United States remains pretty small, scattered cases of West Nile, EEE, SLEV, La Crosse Encephalitis, and a few others are reason enough for health departments across the nation to urge people to follow the `5 D’s’ of mosquito protection:




And finally, to find out about the West Nile threat in your area, you can visit the DVBID website below:

Links to State and Local Government West Nile Virus Web Sites

Click on a state to link directly to their West Nile virus Web page.

See list below for additional city-level and main State Health Department Web sites.

Image: West Nile Virus Map of States with links to their West Nile Virus pages