BOVINE TUBERCULOSIS, BOVINE - USA (03): (NEBRASKA

*************************************
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


Date: 8 Apr 2010
Source: CNBC News



New case of bovine TB found in northeast Nebraska
-------------------------------------------------
A new case of bovine tuberculosis (TB) has been found in northeast
Nebraska, and officials said Wednesday [7 Apr 2010] that at least 7
cattle herds have been quarantined because of it. Nebraska
Agriculture Director Greg Ibach said the new case was uncovered in
Cedar County as investigators looked into a separate case in South
Dakota's Yankton County, where the illness was detected in a herd in January.

Meanwhile, no new cases of the disease were found by investigators
wrapping up a separate case that began last summer in Rock County.

All the herds that have had contact with the Cedar County herd will
be quarantined and tested for the disease, Ibach said. He expected
the quarantine to affect 8 to 12 herds. "I don't believe this new
case is indicative of a TB problem in our state," Ibach said.

Bovine tuberculosis causes severe coughing, fatigue, emaciation and
debilitation in cattle and results in reduced milk and meat
production. Spread by nose-to-nose contact and the inhalation of
bacterium [_Mycobacterium bovis_] usually progresses slowly.

Although rare, humans can catch the disease from contact with
infected cattle. Experts agree that as long as meat is properly
cooked and milk is pasteurized, there is little danger of bovine
tuberculosis spreading through food. [Any carcass with a suspicious
lesion is not allowed into the human food chain in the US. USDA (U.S.
Department of Agriculture) Food Safety Inspection Service (FSIS) is
charged with inspecting meat for just such suspicious lesions. - Mod.TG]

The disease is considered untreatable in cattle. In the past, both
infected and uninfected animals were generally slaughtered when
bovine tuberculosis was found in a herd. But the practice is changing
because the USDA is developing new rules to manage the disease that
focus more on containing the illness instead of eradicating it. [The
disease is contagious but it is slow and insidious. - Mod.TG]

Ibach said a separate state investigation into 2 cases found in a
Rock County herd in June [2009] has concluded. Nebraska officials
tested nearly 22 000 cattle, and a total 61 herds in 20 counties were
quarantined at some point during the investigation. But no additional
cases of the illness were found.

The testing, which began last year [2009], has cost the state about
USD 800 000 so far, even though federal officials pay for the testing
supplies and test processing, Ibach said.

"It's a very costly procedure," Ibach said.

Currently, only 3 herds remain quarantined as part of the Rock County
investigation, and those quarantines will be lifted once those cattle
head to slaughter. The original herd where the disease was found last
year has been released from quarantine.

Ibach said he expects the Cedar County investigation to be smaller
than the Rock County one because the herd with the infected cow had
less fence-line contact with other herds.

--
Communicated by:
HealthMap Alerts via ProMED-mail


[Bovine tuberculosis is caused by _Mycobacterium bovis_. While there
are other _Mycobacterium_ spp, _M. bovis_ and _M. tuberculosis_ are
among the most important, as these tend to move between animals and people.

Disease caused by mycobacteria often develop very slowly and may take
months to years to develop. These bacteria grow very slowly and only
replicate every 12-20 hours. While the pathogenic species (those
which can cause disease) such as _M. tuberculosis_ and _M. bovis_ can
infect a human or an animal, often the individual does not know that
he has been infected. In humans, those infected but without active
disease can be treated to prevent disease from occurring. To prevent
other animals from being infected, a diseased animal must be culled
from the herd.

The disease primarily affects the respiratory tract but can also
spread to other parts of the body. The primary route of transmission
is the exchange of respiratory secretions between infected and
uninfected animals. This can be achieved through nose-to-nose contact
or by the inhalation of aerosol droplets that have been exhaled by an
infected animal. Animals may also become infected with _M. bovis_ by
ingesting the bacteria. This could occur by ingesting feeds that have
been contaminated with _M. bovis_ by other infected animals.
Carnivores may become infected with bovine TB by eating infected carcasses.

Various factors affect the efficiency in which _M. bovis_ is spread
within a cattle herd. The number of infected animals shedding the
organism, as well as the number of susceptible animals present within
a herd can have an impact on the transmission of the bacteria. For
example, the more animals within a herd that are shedding _M. bovis_,
the greater the chance of an uninfected animal coming into contact
with an infected animal. The animal density of a herd also influences
the efficiency of _M. bovis_ transmission. Transmission of _M. bovis_
among animals housed in confinement facilities may be greater because
of close contact. Cattle infected with bovine TB may shed bacteria in
their feces, urine and milk, but these are felt to be a minor source
of bacterial transmission.

Environmental contamination with _M. bovis_ may play a role in the
spread of bovine TB. Survival of _M. bovis_ in the environment is
primarily affected by exposure to sunlight. Reports on the length of
survival of _M. bovis_ vary from 18-332 days at temperatures ranging
from 54-75 F. Under laboratory conditions, _M. bovis_ has been
isolated for up to 8 weeks from various feeds kept at 75 F and 14
weeks from various feeds kept at 32 F. However, under field
conditions, it is difficult to isolate _M. bovis_ from pastures
grazed by animals known to be infected with bovine TB.

Portions of this comment have been extracted from:

- Mod.TG]

[see also:
Bovine tuberculosis, bovine - USA (02): (MI) 20100325.0948
Bovine tuberculosis, bovine - USA: (SD) 20100107.0065
2005
----
Tuberculosis, bovine, human ex cervid - USA (MI) 20050112.0102
2003
----
Tuberculosis, bovine - USA (MI) (02) 20030606.1392
Tuberculosis, bovine - USA (MI) 20030217.0415
2002
----
Tuberculosis, bovine - USA (MI) 20021208.6016
2001
----
Tuberculosis, bovine - USA (Michigan) 20001001.1695
2000
----
Tuberculosis, bovine, deer - USA (Michigan) 20000426.0630
1999
----
Tuberculosis, bovine - USA (Michigan) (02) 19990522.0840
Tuberculosis, bovine - USA (Michigan) (02) 19990519.0822
Tuberculosis, bovine - USA (Michigan) 19990517.0803
Tuberculosis, bovine - USA (Michigan) 19990110.0033
Tuberculosis, bovine - USA (Michigan) 19980923.1899]
....................tg/ejp/mpp

*##########################################################*
************************************************************
ProMED-mail makes every effort to verify the reports that
are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held
responsible for errors or omissions or held liable for any
damages incurred as a result of use or reliance upon posted
or archived material.
************************************************************
Donate to ProMED-mail. Details available at:

************************************************************
Visit ProMED-mail's web site at .
Send all items for posting to: promed@promedmail.org
(NOT to an individual moderator). If you do not give your
full name and affiliation, it may not be posted. Send
commands to subscribe/unsubscribe, get archives, help,
etc. to: majordomo@promedmail.org. For assistance from a
human being send mail to: owner-promed@promedmail.org.
############################################################
############################################################