Johne's Disease (Paratuberculosis)

What is Johne's disease?

Johne's disease, also called paratuberculosis, is a long-lasting infection of the gut caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP). The bacteria slowly thicken the wall of the intestine, so the animal cannot absorb food properly.

Animals are usually infected as young calves, by swallowing bacteria from dung on teats, in milk or colostrum (first milk), or in feed and water. Signs usually appear only years later, in adult animals. Before signs appear, an infected animal can already pass bacteria in its dung and infect others.

Signs to watch for

Common signs include:

• Slow weight loss while the animal keeps eating
• Long-lasting diarrhoea
• Falling milk yield
• A rough, dull coat
• Swelling under the jaw in later stages

Many infected animals show no signs for a long time, so testing is the only way to find them.

Which lab tests help

The Johne's Disease (Paratuberculosis) Antibody ELISA looks for antibodies, the proteins the body makes against the germ, in serum (the clear part of blood) or milk. It is useful for animals with signs and for screening a herd. Early infections often test negative, because antibodies appear late.

The Johne's Disease (MAP) RT-PCR - Faeces looks for the genetic material of MAP in dung. Animals shed bacteria on and off, so one negative result does not rule infection out. The Acid Fast Stain (AFB Stain) on a dung sample may show clumps of acid-fast bacteria, germs that keep a special red stain, but it can miss light infections and cannot tell MAP from similar bacteria.

Other problems, such as worms and liver fluke, can also cause wasting and diarrhoea. A Fecal Worm Egg Count for Cattle & Buffalo and a Faecal Sedimentation Test (Fluke Eggs) help rule them out. The Protein Total, Albumin, Globulin test can show low protein, which goes with the jaw swelling seen in later stages. The Dairy Cattle Health Check combines blood, mineral, protein and worm tests.

Because no single test finds every infected animal, vets often test a herd more than once. A registered veterinarian interprets every result together with the animal's signs and the herd's history.

When to see your vet

Call your vet if an adult animal keeps losing weight or has diarrhoea that does not settle, especially if more than one animal is affected. Ask your vet about testing the whole herd and about prevention.

Testing in Bhopal

Pashupatinath Vet Lab in Shahpura, Bhopal provides free sample collection anywhere in Bhopal. A fresh dung sample in a clean, closed container is needed for PCR and worm tests. From other districts, samples can be sent through your local vet, by courier or by bus parcel; the lab coordinates by phone or WhatsApp on +91 88175 01118. The lab confirms the method, sample needs and reporting time when you book.