Cattle hypodermatosis: symptoms and treatment, preventive treatments

Parasitic diseases can cause significant harm to livestock, affecting cattle, as well as occurring in people who come into contact with farm animals. Most often, herds suffer from cattle hypodermatosis, which can cause significant material losses for livestock producers, as well as dangerous injuries to people.

For what reason the disease occurs

Cattle hypodermatosis is a kind of parasitic disease - entomosis, that is, a disease caused by the penetration of insect larvae into body tissues, cavities and organs of people and animals. Cause of cattle hypodermatosis are gadflies ("cattle flies") of two varieties:

Common subcutaneous gadfly.
Southern subcutaneous gadfly, or esophagus.

Both species are two-winged flying insects, reaching 15 millimeters in adult form. They are capable of laying up to 800 eggs, mainly affecting cattle, but also posing a threat to people involved in animal husbandry or living in areas with a large concentration of cattle.

Insects lay their eggs on the fur of animals, choosing areas where it is the most dense - so it is easier for them to cling to the body. Then, after 5 days, larvae of the first stage hatch from the eggs, which penetrate into the flesh of the animal, moving along the vessels and nerve endings in the direction of the spine. There they penetrate the spinal canal and stay there for six months to nine months in the second stage.

After that, they move to the back and sacrum, where they encapsulate and turn into third-stage larvae. This process takes 17-43 days.

After the specified period, they gnaw their way out, forming fistulas. After a day or three, they turn into pupae.

Symptoms of the disease

Gadfly bites are extremely painful, so animals react to the very approach of insects and their attacks with increased nervousness, they can shy away and make sounds. When the larvae of gadflies gnaw their passages on the body of a cow or other animal, bumpy formations become noticeable under the surface of the skin with inflammation of the surrounding tissues, exudate and suppuration.

When mature larvae gnaw their way out, they leave holes from the formed fistulas, which suppurate and become inflamed, causing severe suffering to livestock.

Hypodermatosis of cattle leads not only to outwardly visible signs of damage, but also causes a decrease in milk yield, weight gain, appetite and behavior disorders, provoked by insect attacks and the actions of larvae.If there are too many of them in the spinal canal, this can lead to muscle paresis and paralysis of the limbs, as well as to the death of animals.

How the problem is diagnosed

When diagnosing cattle hypodermatosis, it is necessary to distinguish its signs from lesions by other parasites, scratching, abscesses, bites, and injuries. Diagnostics is carried out during the period of activity of gadflies, that is, from March to October.

Particular attention is paid to young animals that were born before May, as well as those animals that are kept for fattening.

Only a veterinarian with considerable experience can understand the manifestations of various diseases, so examinations should be carried out regularly, because the only external significant sign of invasion is the presence of bumps on the back and lower back of cattle.

But treatment is effective during the formation of the first stage larvae, so prevention in the form of frequent inspections is the most useful method of combating infection with hypodermatosis in cattle.

Treatment of hypodermatosis in cattle

The treatment procedure is divided into two stages, associated with periods of development of pests in the body of livestock:

The first treatment is carried out from mid-September to mid-November. In fact, it is a prevention, as it allows you to protect the herd from the further spread of gadflies by killing adult larvae. For it, insecticides "Chlorophos" or "Hypodermin-Chlorophos" are used. They are applied with an automatic sprayer along the spine of cows and calves if more than 5 fistulas from gadfly moves are found on their body.
The second stage is carried out from the beginning of March to September to exterminate the larvae that are in the second and third stages of development.Skin areas with bumps and fistulas on them are treated for -2 weeks to make sure that the medicine has worked and no new bumps have appeared. In the latter case, the processing will have to be repeated.

Almost 100% guarantee of the death of larvae of all ages is provided by the use of antiparasitic drugs based on ivermectin. Treatment with organophosphorus preparations based on chlorophos works just as well. All these products are prohibited for use on cows during lactation, as they enter the milk.

Harm to livestock

Each subcutaneous gadfly is capable of laying several hundred eggs, which leads to massive damage to domestic animals. This means that any herd can be affected - and huge numbers of cattle bred on an industrial scale for meat and skins, as well as animals from individual farms of farmers and villagers.

When animals are infected with gadflies, their appetite decreases sharply, which means that they gain weight more slowly, give milk worse and later enter the stage of puberty. Herd owners suffer huge losses due to shortage of production and death of cows and other animals caused by cattle hypodermatosis.

Consequences

Cattle hypodermatosis has the following consequences:

Decrease in milk yield in dairy herds can reach 40-60%. During treatment, it is impossible to use the received milk for food and for feeding calves and other young animals.
Damage to the skin by bumps and fistulas due to gadflies leads to the depreciation of this product, which can ruin a company focused on this enterprise or cause significant material damage to it.
Young animals fattened for slaughter suffer from poor appetite, worry and nervousness. As a result, there is a shortage of mass, and the farm will lose part of the planned profit.
If severely affected, many animals may die, which threatens ruin.
Businesses specializing in the sale of young breeding animals are losing their income due to a ban on the export of livestock from areas affected by gadflies.

All these factors point to the need for a systematic fight against cattle hypodermatosis as a source of great damage to the national economy.

Prevention measures

It is extremely difficult to avoid infection with gadflies, but you can try to reduce the damage caused to them and reduce the mass incidence of cattle hypodermatosis. To do this, you must perform the following actions:

Purchased animals must be treated with special drugs against cattle hypodermatosis before they are allowed into the room or on the paddock where the rest of the herd is kept.
Carry out preventive treatment in the autumn-winter time to destroy the larvae of the first stage.
Do not graze affected cattle and do not sell animals with signs of cattle hypodermatosis to other areas.
Burn manure from a diseased herd, excreted during the active emergence of mature larvae.
Keep clean indoors and pastures, avoid mass gathering of animals on small plots of land.

Because subcutaneous gadflies are ubiquitous, except in the Far North, it is difficult to avoid infection. The only effective way is the preventive treatment of young animals and the entire herd with specialized drugs.

Danger to humans

Hypodermatosis of cattle is a disease dangerous to humans. Most often, infection occurs through contact with sick animals or when in areas with large concentrations of cattle, for example, on pastures, farms, in areas of widespread subcutaneous gadflies.

Infection occurs as follows:

Female gadflies lay their eggs by attaching them to hair on their head or body.
Hatched larvae of the first stage of development are introduced into the subcutaneous fatty tissue and move along it for considerable distances. They can travel up to 12 centimeters in half a day. At the first stage of infection, this happens painlessly and hardly noticeable to the victim.
The next stage in the course of the movement of the larvae, and they move up the body, are cyanotic or reddish inflamed marks on the skin, which disappear in the same place in a couple of days, and then appear again, but on a higher area of the skin.
Moving into the area of the shoulder blades, shoulders, neck and head, the larvae move on to the next stage. They molt, forming a special chamber around themselves, like a chrysalis, protecting them from external influences. The capsule is filled with liquid, and after a couple of days it opens with a fistula. The hole is necessary so that air enters the larva.
There may be several larvae if a person has been repeatedly bitten.

The disease is characterized by severe itching, inflammation and the spread of infection. In the event that only the skin and subcutaneous fatty tissue are affected, the gadfly larvae can be removed surgically. Much worse if the introduction occurred in the area of the eyes, nose, ear canal, mucous membranes. This can cause many dangerous diseases, including the development of blindness, deafness, and death if the larva enters vital organs, such as the liver, lungs, brain or spinal cord.

In the absence of pronounced external signs, it is possible to diagnose cattle hypodermatosis in humans by serological reactions, since when the larvae enter the body, specific antibodies begin to be produced.

Treatment consists of surgical removal of gadfly larvae, oral administration of Ivermectin, and use of Aversectin ointment for external application to the sites of local distribution of parasites. The impact should be complex, carried out as prescribed and under the supervision of a doctor, since the drugs are toxic and have a list of contraindications and side effects. Cattle hypodermatosis is a disease that threatens the he alth and life of not only livestock, but also people, so it is necessary to fight it with all available methods.