A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 23 Apr 2009
Source: Texas Animal Health Commission [edited]
Preliminary test results indicate that a dairy in west Texas is infected
with cattle tuberculosis (TB). Cattle TB is caused by the _Mycobacterium
bovis_ bacteria and can cause internal lesions in animals. Milk from
commercial dairies is pasteurized, killing bacteria with heat, so there is
not public health concern from this herd detection.
"Animals from the 2600-head dairy were being prepared for sale, and some
reacted to TB skin tests. The follow-up blood tests on these animals also
were positive," said Dr Bob Hillman, Texas state veterinarian and executive
director of the Texas Animal Health Commission, the state's livestock and
poultry health regulatory agency. "Samples were collected from 2 of the
cattle slaughtered for examination, and the tissues were submitted to the
National Veterinary Services Laboratory in Ames, Iowa for additional
testing. The lesions are microscopically compatible with TB, and polymerase
chain reaction (PCR) tests on the tissues have detected the DNA, or the
basic genetic material of the disease. The final confirmation is based on a
culture, which may take several weeks. It involves identifying bacterial
growth from the tissue samples as _Mycobacterium bovis_."
"We will be determining the dispensation of the herd in the next few days,"
said Dr Hillman. "An epidemiological investigation has been launched to
determine the source or possible spread of the disease."
Texas regained cattle TB-free status in fall 2006 after losing the coveted
status in spring 2002. Dr Hillman noted that one TB-infected herd would not
affect the state's status, but 2 infected herds within a 48-month period
would result in a loss of TB-free status. Texas' most recent TB-infected
herd was a dairy, detected in 2004 and depopulated. California lost its
TB-free status in September 2008, and Minnesota, Michigan and New Mexico
are split states, meaning areas within these states have different TB
statuses. All other states currently are TB-free.
[The loss of a "free" status for this disease places an extra burden on any
producers selling or shipping animals. There is a cost to testing the
animals, and it certainly requires advance planning to allow a minimum of 3
-- and more likely 5 -- days ahead of when the animals need to be shipped.
The producer can no longer make arrangements and proceed to ship the
animals but rather must test in advance.
It seems likely this will be a positive case. - Mod.TG]
Tuberculosis, bovine - USA (10): (CA) 20081218.3981
Tuberculosis, bovine - USA (09): (ND) 20081208.3856
Tuberculosis, bovine - USA (08): (MN) 20081207.3839
Tuberculosis, bovine - USA (07): (IN) 20081205.3826
Tuberculosis, bovine - USA (03): (MN) 20080222.0718
Tuberculosis, bovine - USA (02): (MN) 20080205.0472
Tuberculosis, bovine - USA (CA) 20080202.0429
Tuberculosis, bovine - USA: (MN) 20080123.0285]