Trichinosis, A Common Disease In Dogs And Cats

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

By nature, cats and dogs are predators. Man is an omnivorous creature, so the food of people and their pets should be significantly different. It is good when the owners have the opportunity to feed their pets with expensive special food, developed taking into account the characteristics of the breed, age and health of the animal. However, not always the owners can afford it, so they have to look for compromise options for feeding animals and combine family-wide food with special additives and animal feed.

In addition, there are especially capricious individuals who categorically refuse even the highest quality special feed. But I have not yet met animals that would refuse natural food - raw meat. Most cats are very fond of fresh fish, fish lovers are not uncommon among dogs.

Oh, how they know how to ask for tasty things! A sweet look, pleading or demanding yapping and meowing, now your cat "serves" on its hind legs, like a dog - and all this for a piece of fresh meat! Well, it is impossible to refuse them in such a situation! When I bring home fresh fish, my cat is literally ready to sell her soul for a small piece. And we follow the lead of our loved ones. And if you managed to buy cheap private meat on the occasion, it's just a sin not to feed your pet with it. Everyone is happy - both the owners and the animals. Meanwhile, feeding with fresh, unheated feed is unsafe for animals. In the previous article (ZooPrice No. 14 - 15) I talked about toxoplasmosis, one of the sources of infection for which is raw meat. In the next articles I want to talk about other parasitic diseases,infection with which is possible as a result of such feeding and how you can avoid them.

We will begin this conversation with trichinosis. Trichinosis in cats and dogs occurs when they are fed with fresh meat that has not undergone heat treatment. The main source of Trichinosis is pork, although there are other sources of this infection in cats and dogs, which I will also discuss. People are also infected with Trichinosis, so everything that concerns the methods of infection applies to them. The causative agents of trichinosis are small larvae of the roundworm Trichina, or Trichinella. These larvae are found mainly in the muscle tissue of the infected animal, but can also infect internal organs. Back in the 19th century, in the countries of Western Europe and in Russia, a mandatory examination for trichinosis of all sold pork, the main source of infection with this disease, was legally established. Therefore, pork purchased in stores and markets iscan be safely eaten by both animals and people - it is mandatory to undergo a study for trichinosis. However, sometimes people buy pork that is sold at low prices outside of official trading places - from cars, or simply "by acquaintance" from a private producer. There are many small informal markets in the suburbs, where prices are significantly lower than in urban areas, but there is no veterinary control. It is such meat that becomes the source of Trichinosis infection. There is no statistics on the incidence of trichinosis in animals in St. Petersburg and the Leningrad Region, but it is known that among people this disease occurs in our country more than 2 times more often than the average in Russia. This is most likely due to the fact that, in addition to our local contaminated meat, meat is often traded in our region,brought from Belarus, which has long been unfavorable for trichinosis.

Scientists distinguish between four types of Trichinella. The worms of three types in the muscles are surrounded by special capsules formed around them by the host organism. The fourth type is special. It is not only capsuleless, that is, the larvae of the parasite are in direct contact with the muscle tissue cell, this species is also distinguished by the fact that it can infect not only mammals, but also birds, both wild and domestic. This is the only species of Trichinella that even hit Australia, other species have not yet reached this continent.

What happens in the body of an animal if we fed it with meat with Trichinella larvae? In the intestines of the animal, when the meat is digested, the larvae enter the lumen of the small intestine and penetrate into its walls. Here, the development of larvae into sexually mature worms takes place, this process lasts about three weeks. Then sexually mature males and females - Trichinella dioecious - go out into the intestinal lumen, where they mate. Trichinella females do not secrete eggs, but give birth to live larvae. One female gives birth to about 1500 larvae! These larvae penetrate into the blood vessels and with the blood flow are carried through the body of the animal, gradually settling in the muscles. Thus, if several hundred larvae enter the animal with food, then, after the reproduction of Trichinella, the infection of the organism increases thousands of times.

The first symptom of trichinosis in animals is diarrhea, which appears 3-5 days after infection. Its intensity depends on how many larvae got into the animal's body with food. Diarrhea usually develops during the development of Trichinella larvae in the intestinal tissues, but can continue after a new generation of larvae has left to colonize the muscle tissue of the animal. The acute state usually corresponds to the period of colonization of muscles by larvae and the formation of capsules around them. Poor animals cannot complain to us about their painful sensations, but it is known that in humans this stage in the development of trichinosis is accompanied by severe muscle pain. A sick animal has a fever, refusal to eat, weakness, severe exhaustion develops. The characteristic symptoms of trichinosis in animals are tremors and impaired coordination of movements. The larvae settling in the muscles secrete substances that destroy muscle tissue, and multiple foci of inflammation develop in the muscles.

I have already written more than once that with helminthiasis, not only the organs affected by worms suffer, but the whole organism as a whole. The toxins secreted by Trichinella cause damage to the nervous system, as well as the development of allergic toxic reactions. Damage to the cardiovascular system is especially dangerous. It is expressed in inflammation of the vascular walls (vasculitis), myocarditis, lowering blood pressure, increased heart rate. On the cardiogram during this period, changes of a dystrophic nature are revealed. It is very dangerous that in acute trichinosis, blood clotting parameters change, and arterial and venous thrombosis often develops. A common complication of trichinosis is pneumonia. All this can lead to death of the animal.

If the animal's body copes with the period of acute trichinosis, the stage of chronic trichinosis begins. During this period, Trichinella larvae, surrounded by capsules formed from the cells of the affected organism, continue to affect the host organism. The capsules germinate with blood vessels, through which the larvae receive the substances they need, and through them they also release the products of their vital activity into the blood of the animal. In this state, they can persist until the end of the animal's life. Long-term existence in the body of Trichinella larvae leads to the development of severe deficiency of the immune system. The body of the animal becomes defenseless against other infections, the animal gradually weakens and eventually prematurely ages and dies.

It is very important that Trichinella infection is accompanied by the defeat of the animal by pathogenic microorganisms. Trichinella bacteria are constantly inhabited by bacteria from the staphylococcus group. They secrete some substances - amino acids, proteins, enzymes, which Trichinella use in their metabolic processes. In addition, staphylococci produce a variety of toxins that help Trichinella spp. Suppress the immune system of the affected organism. In addition to staphylococci, Trichinella spp. Can introduce pathogens of such dangerous infections as rabies, brucellosis, carnivore plague, etc. into the host's body. These microorganisms in Trichinella are transmitted from females to hatching larvae in a number of generations, they themselves do not suffer from them. But animals affected by Trichinella can thus receive, in addition to trichinosis, a whole bunch of diseases.

We now turn to other sources of Trichinosis besides pork. In nature, there are complex ways of circulation of the larvae of this parasite. It involves not only predatory carnivores, but also herbivores, and even insects. Cats often contract trichinosis by eating mice and rats. Dogs can also become infected this way. Cats are susceptible to all four types of Trichinella. Dogs, on the other hand, are relatively resistant to infection by the capsule-free species. It affects only young dogs, and in their bodies the larvae of Trichinella of this species die within several months without causing severe pathologies. Therefore, poultry meat is not dangerous for adult dogs. But if your cat loves to hunt for birds, she can contract trichinosis from them.

Among dogs, trichinosis is especially common in hunting breeds. It would seem that after a successful hunt, it's a sin not to treat your favorite dog with prey! Any wild animals, from wild boars, foxes, bears and badgers to elk and deer, can become a source of infection with trichinosis. By the way, outbreaks of trichinosis among people in Western Europe in recent years have been caused by the consumption of meat from herbivores - horse meat and venison. Therefore, no matter how much the owner-hunter would like to thank his dog for his faithful service, refrain from such manifestations of your love precisely for the sake of preserving the health of the animal! The dog can only be fed such meat after thorough boiling. You can, finally, bake it in pieces over the fire, but just do not give it raw. Without special fears, you can give an adult dog (not a young one!) Only trophies "hunting by pen ".

Preventing trichinosis, therefore, boils down to carefully monitoring what your animal eats. In urban environments, this rule is relatively easy to follow. It is much more difficult to avoid infection if you take your animal out of town in summer. Cats are especially prone to uncontrolled hunting. Therefore, the fight against rodents in a country house, on a garden plot, is important not only for maintaining your health (remember, rodents are one of the sources of infection with hepatitis and other diseases), but also for your animal. Wean your cat from hunting birds from a young age.

Diagnosis of trichinosis in animals is complicated by the vagueness and variety of symptoms. Immunological diagnostics effective in the case of trichinosis in humans has not yet been developed for animals. In case of late diagnosis, the animal may die. If the veterinarian makes the diagnosis on time, trichinosis can be cured. Until recently, animal trichinosis was considered an incurable disease. However, advances in veterinary pharmaceuticals now allow in most cases to cope with this disease. Trichinella itself is destroyed in the body with the help of drugs such as ivomec, cidectin, fenbendazole, levamisole. I do not specifically indicate the dosage of drugs, since trichinosis should be treated only under the supervision of a veterinarian. Concomitant complications are treated at the same time. Complications from the cardiovascular system require special attention. A very balanced approach is required when prescribing hormone therapy. On the one hand, the use of hormones can significantly alleviate the condition of the animal in severe trichinosis. On the other hand, if hormones begin to be used at an early stage of the disease, when not all the larvae of the new generation of Trichinella have left the intestines and dispersed with the blood throughout the body, the use of hormones completely changes the course of trichinosis. The larvae of the new generation remaining in the intestine during hormone therapy do not go into the blood, but again penetrate the intestinal wall, develop and re-hatch larvae, some of which go into the muscles, and the other remains in the intestine again. Against the background of hormones, this process can be repeated many times. Clear,that the infection of the organism with larvae in this case increases by a thousand times. This is the most severe variant of the development of trichinosis. Moreover, if this occurs during the pregnancy of an animal, the larvae enter the developing fetus through the placenta and infect it even in utero. Without hormonal treatment, intrauterine damage to the offspring with trichinosis does not occur.

Unfortunately, sometimes veterinarians, when treating trichinosis, overlook the need to monitor the state of the animal's blood coagulation system. The fact is that, if during the period of acute trichinosis, coagulation increases and the risk of thrombosis is high, then after a course of treatment for trichinosis, when the larvae of the parasite in the animal's body have already been killed, the reverse process begins. Blood clotting decreases, which can lead to internal bleeding. Such a complication of trichinosis, which usually develops during the first weeks after treatment with anti-nematode drugs, can also result in the death of the animal.

E. Kornakova

Fig. V. Glotova