Re: West Nile in Louisiana Aug 5 2002 USA today & Gochfeld questions

<x-charset iso-8859-1>When characterizing this outbreak, little information is being disturbed as
to the vector of the disease. In the past the primary vector has been the Cx
genera which is why there has been low numbers of human cases in most areas,
but an article posted last week refereed to the "southern house mosquito"
and the "tiger mosquito" as being the prime vectors of the outbreak (I have
been unable to find any scientific confirmation). If the Ae. albopictus is a
prime vector, it would explain the high number of human cases, and it would
mean that more human case are likely to be seen in the future, and as far as
WNV in areas with large populations of Aedes albopictus such as LA, TX, and
Okla., they could see a different trending pattern in the number of human
cases of the disease when compared to other areas of the US.

Johnnie Gilpen
Univ. of Okla.

Michael Gochfeld wrote:

> DAN,
> Thanks for forwarding the interesting news item from this morning's USA
> Today. I'd heard it on the radio. I have several thoughts:
>
> 1. I think it pretty much parallels the NY outbreak.
> 2. 55 cases in Louisiana (with all those mosquitoes). Sounds like a
> typical first outbreak. I'd expect at least that many more later in the
> year, and they don't have as much frost to curtail the outbreak.
> 3. I hope they do a serosurvey this year and next to get some estimate
> of silent infections.
> 4. It would be nice to know the age distribution of the non-fatal cases
> as well as the fatal cases.
> 5. It is likely that there will be a shadow epidemic in Lousiana next
> year and then only sporadic cases.
> 6. 22 deaths in three years certainly emphasizes that this is a not a
> major public health issue.
> 7. It's nice that the article emphasizes the control of mosquito
> breeding places (actually more than broadcast spraying, and that the
> spraying of the State's swamps is called into question by a local
> expert).
> 8. There's still very little published about the efficacy of spraying.
> 9. If this builds public health infrastructure, more power to it. If it
> just buys pesticides in bulk it's unfortunate.
> 10. This is still exciting stuff for an avian ecologist-environmental
> health person. The prediction that the virus would quickly spread
> southward was made in Oct 1999. The prediction that it would spread to
> the 100th parallel wasn't made at the time.
> 11. The main avian transporters haven't been clarified.
> 12. . It would be valuable to know about the sequelae in the survivors
> of the encephalitis. Eastern Equine leaves its survivors in pretty bad
> shape. From what I've read, West Nile is most like Venezuelan Equine
> with nearly full recovery. But you never read about such stuff.
>
> Michael Gochfeld
>
> =================================================
> Top News
> Monday, Aug. 5, 2002
> La. Declares West Nile Emergency
>
> SLIDELL, La. (AP) - After four deaths in the
> biggest outbreak of
> the West Nile virus since it was first detected
> in the Northeast
> three years ago, Louisiana's governor declared a
> state of emergency
> and asked for federal aid for more spraying in
> the swampy,
> mosquito-filled state.
>
> The outbreak has infected 58 Louisiana residents.
> The four
> deaths are the first in the country this year,
> bringing the
> national toll to 22 since 1999, when the
> mosquito-borne virus was
> first detected in the New York area.
>
> The virus has since headed west and south. Eight
> people in Texas
> and five in Mississippi are sick with West Nile
> encephalitis, a
> potentially fatal swelling of the brain. The
> virus has been found
> in birds or animals in the Dakotas, Nebraska and
> Oklahoma.
>
> ``It will eventually get to all the Western
> states over time, we
> believe,'' Dr. Roy Campbell, medical
> epidemiologist at the Centers
> for Disease Control and Prevention, said at a
> news conference
> Friday.
>
> The Lousiana victims were three men, ages 53 to
> 75, and an
> 83-year-old woman, all of whom died in the past
> few weeks, state
> health officials said. Twelve people remained
> hospitalized, four in
> intensive care.
>
> ``This is only the beginning,'' said Dr. Raoult
> Ratard, the
> state epidemiologist.
>
> Gov. Mike Foster declared a statewide emergency
> Friday, hoping
> to get $3 million to $5 million in federal money
> for parishes that
> are rapidly using up their mosquito spraying
> budgets.
>
> The virus is carried by mosquitoes that feed on
> infected birds
> and other animals. Most people bitten by the
> infected insects do
> not get sick, but the virus can cause flu-like
> symptoms and
> encephalitis in the weak and elderly.
>
> Until June, Louisiana's only human West Nile case
> was last year,
> in a homeless man in suburban New Orleans. He
> survived.
>
> Experts said the virus has now spread to
> virtually every part of
> watery Louisiana, where mosquitoes are jokingly
> called the state
> bird. The outbreak here is the deadliest since
> the virus killed
> seven people and hospitalized 55 others in the
> New York City area
> in 1999.
>
> Across southeastern Louisiana, people have been
> putting fresh
> water in birdbaths and dumping water out of
> flowerpot saucers to
> deprive mosquitos of the standing water they need
> to breed. St.
> Tammany Parish north of New Orleans has sprayed
> for mosquitoes
> every night for the past month, three to four
> times more often than
> typical during the summer.
>
> Sales of mosquito traps and insect repellents
> have been brisk.
>
> Lois Murphy, 76, said her boss at an antiques
> shop in St.
> Tammany Parish has made all employees apply
> insect repellent. ``He
> makes us spray ourselves twice a day,'' she said.
>
> Dr. Roy Campbell, an epidemiologist at the
> Centers for Disease
> Control and Prevention, said Louisiana residents
> are not
> necessarily at greater risk because of the
> state's bayous and other
> mosquito-breeding terrain. The severity of the
> outbreak depends on
> the species of mosquito, the climate and other
> factors, he said.
>
> Wayne Machado, owner of Mosquito Control Inc.,
> said the species
> that carries the disease usually breeds near
> homes instead of in
> swamps.
>
> Since 1999, the virus has been found in more than
> 30 states,
> reaching Texas, Nebraska, Oklahoma, North Dakota,
> South Dakota,
> Minnesota and West Virginia this year.
>
> Overall, the number of human cases this year has
> already
> surpassed the 64 reported last year; 43 were
> reported in Louisiana
> and Mississippi on Friday alone.
>
> On the Net:
>
> CDC:
> http://www.cdc.gov/ncidod/dvbid/westnile/index.htm
>
> State mosquito control association:
> http://homepages.xspedius.net/cpmc
>
> Louisiana arbovirus database:
> http://arbonet.caeph.tulane.edu

--
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