Barbers pole worm – an unusual but deadly worm in south western Victoria in sheep and alpacas

Adapted from http://www.wormboss.com.au/ Barbers pole worm – or more correctly Haemonchus contortus – is not usually a problem in south western Victoria. However, over the last few years we have seen isolated cases in spring and autumn. Barbers pole worm likes wet warm conditions and this has been the case in some recent seasons. Populations can build quickly because of the worms’ huge egg output. Barbers pole worms are large, blood-sucking worms which can quickly suck blood causing severe anaemia and rapid death in both sheep and alpacas. Haemonchus contortus The barber’s pole worm (BPW), Haemonchus contortus, is quite long (20 to 30 mm) and clearly visible. Only the adult female has the characteristic ‘barber’s pole’ appearance due to the pink (blood-filled) intestinal tract of the worm twisted around the paler reproductive tract. The male worm is smaller (around 15 mm) and pale pink. Females are prolific egg layers, laying up to 10,000 eggs per day. BPW eggs require warm, moist conditions to hatch. Once hatched, however, they develop into tough larvae that can survive for months on pastures before being ingested by grazing sheep or alpacas, where they then grow into blood-sucking adults. Adults can become arrested or inhibited inside the sheep for varying periods. They resume activity when environmental conditions become more favourable or when ewes have lowered resistance around lambing time. Clinical signs Because they are blood-sucking worms, clinical signs include: Anaemia Lethargy Failure to gain weight Submandibular oedema (bottle jaw) Collapse Death Diagnosis The only accurate way to diagnose worm infections before productivity losses have occurred is to conduct a worm test (worm faecal egg...

Why Vaccination is Critical

CHRONIC PULPY KIDNEY – Focal symmetrical encephalomalacia In December a client lost 10 out of 300 six month old lambs he had purchased a few months earlier. The farmer had been told the lambs were fully vaccinated, so no vaccination was done. The lambs were growing perfectly until just before Christmas when 2 lambs became staggery, were unable to rise and died in a few days. Luckily the farmer drenched and vaccinated the lambs with 5 in 1. When one more lamb died, we were called and did a post mortem. Lab testing diagnosed a condition called CHRONIC PULPY KIDNEY or Focal symmetrical encephalomalacia (FSE). In total 10 lambs died before the vaccination took effect. FSE is a form of enterotoxaemia caused by Cl perfringens type D in animals with partial immunity or who suffer only partial intoxication. The signs are referrable to chronic neurological damage. The disease is usually sporadic and affects animals of any age although young animals are more likely to be affected. Clinical signs Clinical signs are similar to those of a condition called PEM or polio. They include blindness, aimless wandering, circling and head-pressing. The sheep become laterally recumbent, mostly quietly but with intermittent paddling and head flexion. The course of the disease varies between 3 and 10 days, before death intervenes. Diagnosis The brain develops soft swellings which can be seen grossly but are fully identified under the microscope. Treatment and prevention There is no effective treatment. Prevention is the same as for pulpy kidney. For a A full description of clostridial diseases of sheep and cattle read the article Clostridial Diseases of...

Clostridial Diseases of Sheep and Cattle

Blackleg, pulpy kidney (enterotoxaemia), black disease, tetanus, malignant oedema and botulism are clostridial diseases that cause death in sheep and cattle throughout Australia. Other animals, particularly goats, are also susceptible. The Clostridial Family of Bacteria Clostridial organisms of various types are found in the soil, where they can survive for a very long time. In fact, when conditions are favourable, some organisms can even multiply in the soil. Most clostridial organisms can also occur quite naturally in the gut of healthy animals. They live there causing no trouble, pass in the manure of animals, and consequently, contaminate the soil. When conditions are favourable for the uncontrolled growth of clostridial organisms they produce powerful toxins (poisons). The effects of these toxins are usually fatal. Diagnosis The most important thing to do when sudden deaths of stock occur is to get an accurate diagnosis. This is important to rule out other conditions, such as metabolic diseases, poisonings and anthrax. Animals suspected of dying from anthrax should not be moved or cut up in any way. Many of the clostridial diseases can look like anthrax and so should be approached with caution. If anthrax is suspected, contact your veterinarian immediately. Clostridial diseases are usually fatal. Death occurs rapidly with pulpy kidney, black disease, blackleg and botulism, but takes several days to weeks with tetanus. In severe outbreaks, many animals die suddenly. Occasional deaths may be due to these diseases also. These are often undiagnosed. Treatment Treatment with antitoxins and large doses of antibiotics is expensive and not usually successful. Vaccination is vital to prevent these diseases. Prevention and Control The major factor...