Transcript 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
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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?
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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
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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
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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
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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
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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
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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
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Wisconsin Department of Health Services
Wisconsin Dairy Industry
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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
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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
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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
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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
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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
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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
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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
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Wisconsin Department of Health Services
Questions?
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