Tuberculosis: When the drugs don’t work

We’ve been talking about tuberculosis (bTB) in cattle (Bos primigenius) and badgers (Meles meles). But why do we care? We care because TB kills people, slowly and horribly. Poor people tend to get it. Until a few decades ago, rich people often got it too. We can get it from milk so in modern times, we in rich countries pasteurise our milk.

In humans, the bacterium which usually causes TB is Mycobacterium tuberculosis spread between people. But people can get TB also from the closely related Mycobacterium bovis. That’s bTB, the kind that we can get from milk and the kind that badgers can get. Since bTB can spread from cows to people, it’s classed as a zoonosis.

Treatments for human TB don’t work very well, as Kathryn Lougheed at the Wellcome Trust explains. That’s why we still care about it.


About argylesock

I wrote a PhD about veterinary parasitology so that's the starting point for this blog. But I'm now branching out into other areas of biology and into popular science writing. I'll write here about science that happens in landscapes, particularly farmland, and about science involving interspecific interactions. Datasets and statistics get my attention. Exactly where this blog will lead? That's a journey that I'm on and I hope you'll come with me.
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7 Responses to Tuberculosis: When the drugs don’t work

  1. narhvalur says:

    Can you explain why not a single Badger in the rest of the World has the Vector that carries over TBC from Badgers to humans. As I recall it is not the same Tubercolosis you get from cows as from poor conditions.

    • argylesock says:

      TB isn’t vector-borne. It’s spread mainly by droplets. So TB and other respiratory diseases tend to spread when people or animals live in poorly ventilated conditions. You probably know that vectors are organisms which spread disease without being the disease-causing organism’s definitive host (the host in which it can complete its life cycle), as mosquitoes spread malaria. TB doesn’t use a vector.

      You’re right that humans and cattle get different species of TB. Mycobacterium tuberculosis in humans, Mycobacterium bovis in cattle. But M. bovis can infect people and spread human to human

      To tell the truth, I know little about badgers outside the British Isles so I don’t know how prevalent TB is in them.

  2. Although it is often stated that TB is a disease of the poor, and the recent increases in the UK have been associated with refugee and illegal immigrant communities, it is not so selective. Any large group of people may be impacted.
    Colleges and Universities are a possible reservoir; one of the University Lecturers I worked with in the 2000s had contracted TB via an outbreak among his students..

    • argylesock says:

      I hope he made it through and enjoyed his life.

      What I’ve heard is that TB spreads when housing is overcrowded, dirty and poorly ventilated. That sounds like some of the student accommodation I’ve known!

  3. EqFe says:

    This response is fact free, but I wonder.
    I always thought that most of us were\will be exposed to TB during our lives, but that we won’t show symptons unlsess our immune system was compormised. As a kid we used to have a screening test for TB, and I always had positive signs, and without doing anything about it the doctor always said don’t worry about it. During the hieght of the AIDS crisis in the US youn men in this country were showing signs of full blown TB in record numbers.

  4. Pingback: Tuberculosis in cattle and people | Science on the Land

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