New findings on the diagnosis of paratuberculosis in goats

Jun 11, 2012 By Kari Røste Lybeck

Measuring immune responses with the help of a so-called interferon gamma test can help to diagnose paratuberculosis in goats.

However, infection in was discovered later than expected when this test was used and a positive test result can be inhibited by other immune responses in the animals, reveals a PhD project carried out at the Norwegian Veterinary Institute.

Paratuberculosis is a of the intestines occurring in and caused by the Mycobacterium avium paratuberculosis (MAP). This disease can lead to significant production losses and negatively affect .

Interferon gamma (IFN-γ) is a neurotransmitter in the immune system which it is believed plays an important role in protecting the body from MAP. It is difficult to diagnose the disease at an early stage, but a test that measures IFN-γ production in the blood is considered to have the greatest potential for diagnosing paratuberculosis at an early stage of the disease. An IFN-γ response is normally expected to occur before an antibody response, whereas an antibody response is more dominant than IFN-γ production in the advanced stages of the disease.

Kari Røste Lybeck has studied goats naturally infected by the paratuberculosis bacterium and results from her research show that the IFN-γ test can be a useful tool for diagnosing this disease in goats in Norway. However, the goats showed a positive reaction to this test at a later stage than expected. Other ways of diagnosing the disease, such as the detection of antibodies in the blood or bacteria in faeces, were able to detect the disease at an equally early stage in some cases.

Contrary to expectations, the results of Lybeck’s doctoral research demonstrated that the IFN-γ response remained high, even in suffering from advanced stages of the disease, when they were secreting large concentrations of paratuberculosis bacteria in their faeces and showing serious symptom changes. It was therefore not easy to prove that the IFN-γ had the anticipated protective effect.

Lybeck’s research also showed that another neurotransmitter, interleukin-10 (IL-10), could limit the production of IFN-γ. Inhibiting IL-10 increased the sensitivity of the IFN-γ test, but simultaneously lowered its rate of accuracy. Many of the infected goats had serious changes in symptoms and also a higher than normal level of IL-10, both in their blood and their damaged bowel tissue. It is possible that the IL-10 production may have made the infection worse, but it could also be that the IL-10 was merely the consequence of an extensive inflammatory process.

To sum up, this study provides useful knowledge about the development of immune responses to a paratuberculosis infection and about the diagnosis of paratuberculosis in goats.

The research was financed by the Norwegian Research Council and by TINE BA and was carried out at the Norwegian Veterinary Institute from 2006-2012. The project “Healthier Goats” was a key collaborator.

DVM Kari Røste Lybeck defended her doctoral research on 6th June 2012 at the Norwegian School of Veterinary Science (NVH) with a thesis entitled:

”Mycobacterium avium subsp. paratuberculosis infection in goats - immune responses and diagnosis with emphasis on production”.

Explore further: Scientists target mess from Christmas tree needles

add to favorites email to friend print save as pdf

Related Stories

When helper cells aren't helpful

May 24, 2010

Current research suggests that T helper-type 1 (Th1) cells, previously thought to mediate autoimmunity, may actual inhibit the development of experimental immune encephalomyelitis (EAE), a mouse model of multiple sclerosis ...

IL-32 expression upregulated in chronic rhinosinusitis

Apr 17, 2012

(HealthDay) -- Interleukin-32 (IL-32) mRNA expression is significantly higher in biopsies obtained from patients with chronic rhinosinusitis (CRS), compared to levels found in biopsies obtained from individuals ...

Stem cells could halt osteoporosis, promote bone growth

Mar 04, 2009

While interferon gamma sounds like an outer space weapon, it's actually a hormone produced by our own bodies, and it holds great promise to repair bones affected by osteoporosis. In a new study published in the journal Stem Ce ...

Mutation leads to new and severe form of bacterial disease

Dec 18, 2009

(PhysOrg.com) -- Everybody gets sick, but how sick you get is in your genes. New research now reveals a mutation on a gene that makes children susceptible to a severe form of mycobacterial disease. The work not only supports ...

Recommended for you

Keep dogs and cats safe during winter

5 hours ago

(HealthDay)—Winter can be tough on dogs and cats, but there are a number of safe and effective ways you can help them get through the cold season, an expert says.

Scientists target mess from Christmas tree needles

Dec 26, 2014

The presents are unwrapped. The children's shrieks of delight are just a memory. Now it's time for another Yuletide tradition: cleaning up the needles that are falling off your Christmas tree.

The ants that conquered the world

Dec 24, 2014

About one tenth of the world's ants are close relatives; they all belong to just one genus out of 323, called Pheidole. "If you go into any tropical forest and take a stroll, you will step on one of these ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.