Surra (Trypanosomiasis)

What is surra?

Surra, also called trypanosomiasis, is a disease caused by Trypanosoma evansi, a tiny single-celled parasite with a whip-like tail that swims in the blood. Biting flies carry it from one animal to another as they feed. Dogs can also be infected by eating raw meat or offal from an infected animal.

In cattle and buffaloes, surra often runs a slow course, with fever that comes and goes, weight loss and anaemia (a shortage of red blood cells). Many buffaloes carry the parasite with few or no signs and can be a source of infection for other animals. In dogs, surra is often severe and can be fatal. Cases are more common in and after the rainy season, when flies are plentiful.

Signs to watch for

Common signs include:

• Fever that comes and goes
• Pale gums and eyes
• Weight loss and weakness, even when the animal eats
• Swelling of the legs, lower belly, face or throat
• A drop in milk, or abortion in pregnant animals
• Cloudy eyes, often seen in dogs

Not every animal shows every sign. In severe cases, an animal may walk in circles, press its head against walls or have fits.

Which lab tests help

Trypanosome Detection (Wet Film & Buffy Coat Smear) looks for the parasite in two ways. A wet film is a fresh drop of blood under the microscope, where trypanosomes can be seen moving. A buffy coat smear uses the thin layer of white cells that forms when blood is spun, where the parasites gather. A sample taken during a fever is more likely to show them, and a stained Blood Protozoa (Blood Parasite Smear) can also pick them up. Parasites come and go in the blood, so a negative smear does not rule surra out.

Trypanosoma evansi (Surra) RT-PCR finds the parasite's DNA and can pick up low-level infections that a smear misses. The Trypanosoma evansi (Surra) Antibody ELISA shows whether the animal has been exposed. Antibodies can stay for some time after the infection has gone, so a positive result does not always mean active disease. A Complete Blood Count (CBC) shows anaemia.

A registered veterinarian interprets every result together with the animal's signs and history. The lab confirms the method, sample needs and reporting time when you book.

When to see your vet

See your vet promptly if a cow, buffalo or dog has a fever that keeps coming back, pale gums, swelling or weight loss. A dog with cloudy eyes, a swollen face or weakness needs a vet the same day, and any animal with fits or circling needs a vet at once. Ask your vet about fly control and other prevention.

Testing in Bhopal

Pashupatinath Vet Lab is at C-200, C Sector, Shahpura, Bhopal, and sample collection is free anywhere in Bhopal. From other districts, samples can be sent by courier, by bus parcel or through your local vet; call or WhatsApp +91 88175 01118 to plan this. Reports are shared on WhatsApp, by e-mail and in My Reports on the website.