RE: Ornithologists Respond #2 re: Bird die-off in Argentina & WNV

<x-flowed>Dr. Wayne Crans at Rutgers has found evidence that EEE virus is reintroduced
into New Jersey in the spring when migratory birds that were infected the
previous year return. Apparently, birds can be infected and recover,
complete their migratory round trip, and become viremic again (recrudesce)
the following spring under the stress of mating season. The viremic birds
then re-infect the local mosquitoes. If this is true for EEE, it would seem
plausible that a bird could contract WNV in North America, recover, fly
south and then infect mosquitoes in its "winter" home if something occurs to
make the bird become viremic again. Needless to say, there is no evidence
that this happens, but it seems plausible enough to a non-ornithologist like
myself that it may bear looking into. However it happens, it is clear that
WNV can spread rapidly, and there are no obvious reasons why t should not
reach South America.

-----Original Message-----
From: Environmental Risk Analysis Program [mailto:envrisk@cornell.edu]
Sent: Tuesday, January 14, 2003 3:28 PM
To: WESTNILEVIRUS-L@cornell.edu
Cc: promed@promedmail.org
Subject: Ornithologists Respond #2 re: Bird die-off in Argentina & West
Nile Virus

A second batch of compiled responses to the question posted yesterday
(re: possibility of connection between bird die off in Argentina &
West Nile Virus):

(4)
From: Ashley Lovell <Ashley.R.Lovell@aphis.usda.gov>
Date: Tue, 14 Jan 2003

I find it surprising that a previous ornithologist* made the comment
that WNV might arrive in Argentina (or anywhere for that matter) via
an infected human. It is quite unlikely that this would occur since
humans, like horses (for the most part), are incidental hosts. Yet
I see this statement made in information publications, by scientists,
and mentioned in the popular media quite often, and it baffles me.
In addition, it is plausible (and in fact believed by many) that a
bird infected with WNV would and could migrate through its normal
migration range. Several species of birds that might become infected
with WNV are capable of migrating because incubation times vary from
species to species, and viremia levels vary from bird to bird.

Ashley Lovell
USDA/APHIS - Wildlife Services
1445 Federal Drive, Room 222
Montgomery, AL 36107

[*WestNileVirus-L moderator's note: this is a reference to comments
made by Ellen Paul <epaul@concentric.net> #(3) in the previous
posting]

(5)
From: Timothy Male <tmale@environmentaldefense.org>
Date: Tue, 14 Jan 2003

Concerning the Argentine bird deaths, as the authors below note, it
seems unlikely that any of the species mentioned are migrants
directly involved in spreading the virus from North America to South
America. However, this overlooks the more likely scenario in which
migrants spread the virus to South America and then the virus
appears, potentially, in both resident and migratory bird faunas.

That said, it seems likely that this is not a set of bird species
likely to be indicative of a west nile outbreak (pigeons, for
instance, are not known for their wnv susceptibility nor are
cardinals (Red-crested Cardinal and Yellow-billed Cardinal are, I
believe, non-migratory species present in Argentina)) and seems more
likely to be due to pesticide exposure. If bird mortalities
continue, then perhaps there there would be greater concern over wnv
as the causitive agent?

Timothy Male, PhD.

Wildlife Scientist
Environmental Defense
1875 Connecticut Avenue, NW
Washington, DC 20009

(202) 387-3500
(202) 234-6049 fax
tmale@environmentaldefense.org

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