Download TB in Four- and Two

Wisconsin Department of Health Services
TB in Four- and
Two-Legged Animals
Lorna Will RN, MA
WI Division of Public Health
WMLN 2013
WMLN October 2013
Wisconsin Department of Health Services
What is the problem?
• Wisconsin has a few cases of TB disease each
year in humans working with four-legged
animals
o Dairy and beef farms, zoos, pet stores…
• WI has 1-2 cases of TB disease in humans due
to M. bovis each year; cattle and other fourlegged animals are very susceptible to M. bovis
• Most mammals can get TB – bovis or MTB
WMLN October 2013
2
Wisconsin Department of Health Services
What is the problem?
• A case of TB in a Mexican farmworker in
2012 crossed 5 WI counties and involved
hundreds of people during the year the patient
was thought to be infectious
• As he was infected with M. tuberculosis, no
investigation of the herds he worked with was
done.
• Was this correct?
WMLN October 2013
3
Wisconsin Department of Health Services
What is the problem?
• There is no national protocol for investigating
a herd (or other group of animals) which have
been exposed to human TB, whether M. bovis
or M. tuberculosis
• Source of M. bovis TB in US is largely
Hispanic workers infected by ingestion of
unpasteurized dairy products from infected
cows
WMLN October 2013
4
Wisconsin Department of Health Services
What is the problem?
• M. bovis infection is NOT a problem in US
herds, except in California and the lower
peninsula of Michigan
• Pasteurization kills TB
• M. bovis is very transmissible to herds; MTB
less so
WMLN October 2013
5
Wisconsin Department of Health Services
What is the problem?
• The cost, both in terms of $ and animals, to an
individual farmer and to the state, if a cow is
found to be positive for TB, is enormous
o California: single cow found + at necropsy; more
than 400,000 cows had to be traced at a cost of
almost $2 billion
o Herd is quarantined and repeatedly tested; any
herds that share a fence line are also quarantined
and tested
WMLN October 2013
6
Wisconsin Department of Health Services
What is the problem?
• The cost, both in terms of $ and animals, if a
single cow is found to be positive for TB, is
enormous
o Wildlife in the quarantine area are tested by DNR
o No animals may be moved until herd is clear
unless the farmer chooses to depopulate the herd;
then premises are decontaminated and farmer may
start over
o Product cannot be shipped
WMLN October 2013
7
Wisconsin Department of Health Services
What is the problem?
• The cost, both in terms of $ and animals, if a
single cow is found to be positive for TB, is
enormous
o If the herd is not depopulated, the herd is retested
over the next five years
o Milk can be sold as long as any milk from positive
animals is kept out of the bulk tank
o Movement is restricted
WMLN October 2013
8
Wisconsin Department of Health Services
The Dairy Industry in WI
• The dairy industry is an annual $26.5 billion
industry in Wisconsin
• 86.8% of farms are family-owned
• There are about 12,000 dairy farms in WI
WMLN October 2013
9
Wisconsin Department of Health Services
Wisconsin Dairy Industry
WMLN October 2013
10
Wisconsin Department of Health Services
The Plan
• Advice of what to do when a farmworker tests
positive for TB has varied over the years and is
not consistent
• Since there is no national protocol (or even any
final state protocols) we decided to create our
own
• Major point is communication – LHD, DPH,
DATCP, DNR, APHIS, USDA
WMLN October 2013
11
Wisconsin Department of Health Services
DPH-specific actions
• Identify prevalence of TB infection
o Farm worker testing: Marathon, Buffalo, Pepin
Counties
o Majority of farm workers there are Hispanic; many
undocumented
o Initial testing (both of contacts to the known case
and as part of prevalence testing) results in
between 3 - 4% infection rate among workers
tested
WMLN October 2013
12
Wisconsin Department of Health Services
DPH-specific actions
• Prevalence of infection is thought to vary by
state in Mexico, so those data are now being
collected when workers are tested.
• Need to expand testing; farmers have been
uneasy (as are workers)
• As protocol is made final, will work with UW
Extension and industry to recommend testing
of workers and treatment of any with infection
WMLN October 2013
13
Wisconsin Department of Health Services
Draft Protocol
• Priority is dairy industry; more workers with
more close contact with animals
• Could also apply to zoo and pet shop human
cases; zoo and pet shop 4-legged cases rarer
than human
• Two-way notification of either positive cow or
positive human
• Identification of human activities around cows
to try to quantify risk to herd
WMLN October 2013
14
Wisconsin Department of Health Services
Draft Protocol
• Usually have to wait at least 12 weeks to get
final genetics of human TB and know whether
it is M. bovis or MTB
• PCR for M. bovis available at Wadsworth lab
in NY; decision to request test (and set up
contract with them) will be based on actual
incidence of M. bovis TB and amount of risk to
herd
WMLN October 2013
15
Wisconsin Department of Health Services
Draft Protocol
• DATCP and USDA may be aggressive in herd
testing at beginning to try to establish extent of
risk with carefully identified worker activities
o Testing is paid for by gov’t and farmers are
reimbursed for any cattle culled
• DNR will be notified if human with TB had
any activities with wildlife OR if a positive
cow could have been in contact with wildlife
WMLN October 2013
16
Wisconsin Department of Health Services
Draft Protocol
• Hope to complete group approval of protocol
this fall
• Work with industry and UW over winter and
into spring
• Continue to emphasize testing and treatment
for the high risk population of Mexican-born
farmworkers
WMLN October 2013
17
Wisconsin Department of Health Services
Questions?
WMLN October 2013
18