Posted on 05/22/2012 11:35:03 PM PDT by neverdem
Cattle infected with a common parasite could be spreading TB across Britain undetected.
Bovine tuberculosis (bTB) could be spreading across Britain because the most widely used test for the disease is ineffective when cattle are infected with a common liver parasite.
The liver fluke Fasciola hepatica was already known to affect the standard skin test for bTB, but it was unclear whether the fluke stopped the disease developing or merely hid the symptoms. A study published today in Nature Communications suggests that the latter is more likely, and that the effect is significant. It estimates that around a third of bTB cases in England and Wales are undiagnosed because the test is less sensitive in cattle infected with the fluke1.
Researchers tested milk from dairy herds across England and Wales for antibodies against F. hepatica, an indication of infection, and added the data to an existing model of bTB transmission. If they assumed that a fluke infection inhibited bTB detection, they achieved a closer match between the model and actual bTB detection rates. The authors suggest that the fluke may alter the production by T lymphocytes — key cells in the immune system — of the protein interferon-γ, which is crucial to a genuine result in both the skin test and the second most common test for bTB, the interferon-γ release assay (IGRA) blood test.
Diana Williams, an infectious disease specialist at the University of Liverpool, UK, and an author of the paper, says the result helps explain why bTB is still endemic across England and Wales. “Everyone is aware that current methods aren’t detecting early enough or with enough sensitivity,” she says. “We need to look at better control of fluke.”
But the Department for Environment, Food and Rural Affairs, which is responsible for bTB control in Britain, questions...
(Excerpt) Read more at nature.com ...
P.S. Nature News linked a FReebie.
Which henceforth shall be know as the liver "slut". :)
Note that they are in no way alarmed about the Liver Fluke vector, which is potentially far more devastating to humans than TB.
People often live 60 years or more with TB. The TB specialists say that “you have to work at it to die of TB.”
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