Wednesday, August 22, 2012

CDC Telebriefing on West Nile Virus




# 6510


A public health situation we’ve been following here for the past several weeks (see here, here, here, and here) was the subject of a CDC telebriefing today; the unusually high incidence of West Nile infections across the country, but most noticeably in Texas.


According to the CDC’s Dr. Lyle R. Petersen, director of the DVBID at the CDC, 2012 may be on track to be the worst yet in the 13 year history of the virus in the United States.


Yesterday, the CDC’s DVBID division updated their numbers through August 21st, indicating:


2012 West Nile virus update: as of August 21

Thus far in 2012, 47 states have reported West Nile virus infections in people, birds, or mosquitoes. A total of 1118 cases of West Nile virus disease in people, including 41 deaths, have been reported to CDC. Of these, 629 (56%) were classified as neuroinvasive disease (such as meningitis or encephalitis) and 489 (44%) were classified as non-neuroinvasive disease.


The 1118 cases reported thus far in 2012 is the highest number of West Nile virus disease cases reported to CDC through the third week in August since West Nile virus was first detected in the United States in 1999. Approximately 75 percent of the cases have been reported from 5 states (Texas, Mississippi, Louisiana, South Dakota, and Oklahoma) and almost half of all cases have been reported from Texas.



Of the 1118 cases, nearly half (n=537) are from Texas, and 26 deaths so far this year have been recorded in the Lone Star State. Hard hit Dallas county reported their 11th fatality yesterday.


Elsewhere across the nation, 38 other states have reported West Nile infections in humans, and deaths have been reported across 16 states.


Of note, Louisiana has reported 6 fatalities and Oklahoma has reported 3.


Today’s telebriefing featured Lyle R. Petersen, M.D. and the transcript should be posted on the CDC’s media site tonight or tomorrow (now available at this link).


Lisa Schnirring writing for CIDRAP NEWS has an excellent summary of today’s briefing:


CDC reports surge in US West Nile virus activity

Lisa Schnirring * Staff Writer

Aug 22, 2012 (CIDRAP News) – The United States is experiencing a dramatic rise in the cases of West Nile virus (WNV) infections over the past month, with record-setting numbers expected over the next several weeks and the US Centers for Disease Control and Prevention (CDC) warning people to take key preventive steps.


So far, 38 states have reported human cases, but the epicenter is Texas, which has reported half of the WNV infections. The CDC said so far it has received reports of 1,118 cases, including 629 people with the neuroinvasive form of the disease. Nationally, 41 deaths have been reported.

(Continue . . .)




Given that the WNV season doesn’t usually peak until mid-August, and it can take 2 to 3 weeks for symptoms to develop, many more cases are expected over the next few months.


While 80% of those infected don’t show symptoms, last week WEBMD carried a report (see New West Nile Threat: Kidney Disease) about research conducted by Baylor University West Nile expert Kristy O. Murray, PhD, DVM.


Dr. Murray’s research (see Persistent Infection with West Nile Virus Years after Initial Infection) suggests long-term sequelae may develop among a significant percentage of those who are infected with the West Nile Virus – even among those infected asymptomatically.


Dr. Murray was awarded an NIH grant in 2011 to study the effects of chronic WNV infection on the kidneys and central nervous system.


Reason enough to take seriously the recommendations from health departments across the nation that urge people to follow the `5 D’s’ of mosquito protection:


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

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

And as a final note, the CDC recently updated their information on mosquito repellants.

Updated Information regarding Insect Repellents