Animals like cats, ferrets, lions and cows can carry Tuberculosis (TB) and pass it onto humans.
In 2014, the United Kingdom confirmed its first known cases of cat-to-human TB transmission. Queen's University Belfast researcher Irene Grant says even a case of lama-to-human TB transmission was recently reported.
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The domesticated UK cats that made UK headlines as TB vectors carried the strain of TB named “Mycobacterium bovis,” bovis being latin for “cow.” That’s right, cows carry TB and can spread it to not only other animals but also humans, largely via the consumption of infected meat or unpasteurised milk.
A study conducted among about 460 cows and 3,130 abattoirs in Nigeria found that about 40 percent of herds surveyed carried bovine TB. According to University of Ibadan researcher Simeon Cadmus, the research also showed the bacteria’s incredible ability to move through our food chain.
“Most of the butchers and traders had TB but one had (bovine TB),” said Cadmus, who presented his findings at the World Lung Health Conference going on now in Cape Town. “That specific strain of (bovine TB) was also found in the milk of a pastoralist’s hut.”
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Cadmus noted that the sale and consumption of unpasteurised milk is common among pastoralist communities that also make use of unregulated butcheries to slaughter animals. Cows and their meat are never screened for TB, which means these communities eat not only infected meat, but also organs like the lungs home to TB-filled lesions. In fact, lungs are considered a delicacy, he adds.
Cow TB is about 99.9 percent identical to human TB and only very sensitive testing can differentiate between the two, which is bad news for human patients.
“Animal TB forms are naturally resistant to the drug pyrazinamide,” said Dr. Francisco Olea-Popelka, an assistant professor at the College of Veterinary Medicines and Biomedical Sciences at Colorado State University in the United States, the only country in the world that regularly tests TB patients for bovine TB.
Olea-Popelka adds that animal TB is often located outside the lungs, making it more difficult to detect with regular screening tools and treatment is about three months longer than that for regular TB. With a longer treatment time, people living with animal – or “zoonotic” – TB may tire of treatment and may be more likely to skip daily doses, which could fuel drug resistance, Olea-Popelka adds.
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A World Health Organisation report released this week found that about 121,000 people bovine TB in 2010 and about 10,500 died from it.
However Olea-Popelka cautions that no one really knows the world’s true burden of the bacteria that is already endemic to parts of India such as Tamil Nadu state, according to Krishna Prasad Hanumanthappa of New Delhi’s All India Institute of Medical Sciences.
India has also discovered that elephants can carry disease, leaving animal wildlife officials with a tough choice about whether or not to cull infected endangered elephants.
Studies among different populations globally have shown prevalence rates of TB bovine ranging from just about one percent to 30 percent. Farm workers and those from rural areas may be most at risk.
“The people affected by the disease are the most neglected, living in areas far away from health centres,” Olea-Popelka says. “They are the very same people in charge of producing the food for the rest of us.”
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But if new research has you looking twice at your furry companion or your burger, fear not. England’s Department of Health has stressed that cat-to-human TB transmission is incredibly rare.
In South Africa, commercial livestock are regularly screened for TB to safeguard meat and diary products, according to Stellenbosch University Medical Research Centre Director Paul van Helden.
Commercial cows found to have contracted TB are killed and farmers are compensated. State veterinarians are then supposed to monitor the larger herd every six months until the herd is declared TB-free.
However, Helden said that more surveys should be conducted to find not only the bovine TB prevalence in rural areas but also among wildlife such as buffalos in conservation areas.
At least two-dozen mammal species are confirmed to carry TB in South Africa. – Health-e News.
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