Friday, July 2, 2010

Anthrax, Cattle, Texas

A ProMED-mail post

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International Society for Infectious Diseases

Date: Fri 2 Jul 2010
From: Martin Hugh-Jones [edited]

Anthrax deaths in Uvalde County, Texas
Last Fri 25 Jun 2010, I was reliably informed that the Texas A & M
veterinary diagnostic laboratory, College Station, had confirmed a
case of anthrax in a white tailed deer in Uvalde County. On Tue 29 Jun
2010 I was able to confirm this with the veterinarian who had examined
a freshly dead deer from a ranch in the northern part of that county,
and submitted its spleen to College Station on 22 Jun 2010. Apparently
some 10 or so deer had died earlier on this deer ranch near Rock
Springs. This is a freshly purchased ranch and the new owners had put
up an 8 ft [2.5 m] fence around it. When they did this the new fence
enclosed an uncertain number of wild white tails. The anthrax deaths
were seen in this group. The ranch has expensive penned breeding deer
but they had been vaccinated and suffered no losses.

So I checked with my various rancher friends in that part of the
Edwards Plateau, and apart from 2 dead deer found on a ranch near the
Devil's River, no one has seen anything untoward. However a very
informed contact in Rock Springs told me the following about recent
multiple deaths in that area; "These old ranchers have seen many
animals die from anthrax over the years. You can't get them to send
anything in. I can't confirm these cases, but I am 99 percent sure
they died from anthrax. We have had about 10 horses, 15 bulls and
cows, 35 deer, 3 sheep, and 1 aoudad [imported N. African wild sheep
-- see

reported. The old timers say if it would rain it will stop. They say
we need to get 2 inches or so. It is trying to rain this morning so
maybe we will get some." He had lost one bison. Since then they have
been visited by the [hurricane] Alex rains. The total number of
affected ranches at this time around Rock Springs is unclear.

The underlying reason the ranchers would want rain is that it washes
the infected blow-fly vomit off the browse so it is then safe for the
deer to eat. After feeding on an anthrax carcass blow flies fly to a
nearby shrub to vomit up their blood meals to get rid of the excess
fluid. They then eat and digest the red blood cells. This leaves a
residue on the leaves; the anthrax vegetative cells sporulate; and the
spores lurk there until eaten by a passing deer or the leaf falls off,
or the spores are washed off by rain. Thus the spores can be on the
scrub leaves for weeks posing a constant threat until they are removed.

Apparently because there has been only one laboratory confirmed case
the Texas Animal Health Commission is not issuing a report warning the
area cattlemen to get their animals vaccinated if they hadn't done it
earlier in the year.

As and when I get updates on this situation, they will be posted.

Martin Hugh-Jones
ProMED-mail Animal Disease Moderator

[The state of Texas can be located on the HealthMap/ProMED-mail
interactive map at
Uvalde County can be located on the map at
Edwards Plateau and Rock Springs can be seen on the map at
. -

[see also:
Anthrax, bovine - USA (03): (TX), cervid 20090817.2910
Anthrax, bovine, wildlife - USA (TX) 20070713.2246
Anthrax, deer - USA (TX)(03): bull affected 20060726.2057
Anthrax, deer - USA (TX)(02): susp. 20060720.1994
Anthrax, deer - USA (TX) 20060710.1891
Anthrax, cervidae, livestock - USA (TX) 20050709.1944
Anthrax, bovine, deer - USA (TX) (02) 20040829.2415
Anthrax, bovine, deer - USA (TX) 20040812.2231
Anthrax, deer - USA (Texas) 20030808.1956
Anthrax, deer - USA (Texas) 20020915.5322
Anthrax, deer, bison, human - USA (Texas) (04) 20010715.1371
Anthrax, deer, bison, human - USA (Texas) (03) 20010712.1344
Anthrax, deer, bison, human - USA (Texas) (02) 20010707.1306
Anthrax, deer, bison, human - USA (Texas) 20010703.1278
Anthrax, deer - USA (Texas) 20010622.1184]
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