The term horse roundworm refers to a roundworm that has infested a horse’s organism. Any horse pasture is considered infested because the eggs of a horse roundworm remain viable for up to 10 years, which means they can be transmitted to other horses and humans for a long time.
What is horse pulworm?
Horse pulworm is not a separate species, but it is the common roundworm. Usually these parasites infect humans, monkeys, but also bears. The roundworm does not require an intermediate host such as a horse, but it can be transmitted directly from the horse to humans. The horse roundworm is considered particularly prolific and vicious, as females can lay up to 200,000 eggs at a time, which remain viable for 10 years. Within the egg of a horse pulworm is a larva that hatches under favorable conditions. For this reason, any horse pasture is basically considered infested; however, infections only break out in poor sanitary conditions in the horse barn. Horse roundworm can cause severe damage to the intestines, liver and lungs in horses and can lead to the death of the animal, especially if the affected horse was already not healthy before. Roundworms, and therefore horse roundworm, are nematodes that reside primarily in the intestines of their host and spread from there throughout the body.
Occurrence, distribution and characteristics
The roundworm itself is found worldwide. The horse roundworm, on the other hand, is found primarily in horse pastures, horse stables, and where horses apple. This form of roundworm mainly jumps to people who work with horses or spend their free time intensively with the animals, including cleaning stables or pastures. At first, a foal has no contact with the horse roundworm until it comes to a pasture for the first time. This is because from then on, the horse pulworms are transmitted to the foal from the older animals grazing there – but it does not necessarily have to become infected if its immune system is healthy. Since foals already come into contact with the horse powderworm in principle, however, individual worms penetrate the organism quite frequently and pass through it. Healthy horses thus develop a reliable resistance to the horse powderworm until about the second year of life, which is why real infections become increasingly rare from this age onwards. Deworming provides the final protection against it. However, caution is advised with foals and yearlings. On average, the many eggs of a roundworm can be expected to remain infectious for up to 4 years. This means that the larvae in the egg could hatch at any time and reproduce themselves in the host. In the case of the horse roundworm, this is even a maximum of 10 years. The horse powderworm egg has this resistance because it has three shells. It is thus optimally protected against severe drought, chemical substances and high temperatures. It is estimated that about 22% of the world’s human population is infected with roundworms, which come not only from a horse, but also from other hosts. About 1% succumb to worm infection. The female horse roundworm can grow up to 40 cm long and 5 mm wide, while a male worm grows up to 25 cm long and 3 mm wide. Visually, horse pulworms resemble an earthworm. The parasites have a life expectancy of about 1 1/2 years per individual. They can move independently and are capable of penetrating the walls of internal organs such as the small intestine or liver without causing life-threatening or even serious internal injury to the host.
Diseases and ailments
Equine roundworm infection manifests in relatively similar ways in horses and humans. The larvae are first ingested; in horses, this occurs by grazing in a place where an infected animal has peeled. The larva enters the small intestine, hatches and perforates the intestinal wall. It then enters the liver and finally the lungs, where it can cause a coughing fit and, in the worst case, pneumonia. Both horse and human cough from this and thereby either get rid of the larva or swallow it. This causes it to re-enter the small intestine, where it now develops into a full-grown horse powderworm. Only two months after the penetration of a not yet hatched larva of the horse powderworm, it can be detected in the feces. This means that the cause in horses and humans is not yet detectable in the feces with the first appearance of the cough.Another risk besides severe pneumonia is blockage in the small intestine if too many equine roundworms reside there. Life-threatening intestinal obstructions and blockages can occur, especially in horses, but also in humans. Adult horsepulworms can further block the pancreatic ducts and cause colic, result in malnutrition or, due to biochemical processes and changes in the body of their host, attempt to leave the host through body orifices such as the mouth or nose. An example of this is anesthesia. Severe allergic reactions are possible to the larvae and adult stages of the equine roundworm, which in turn lead to the death of the host. Further complications may result from inflammation of the lungs of an infested host, such as excessive fever or asthma-like coughing attacks.
