The larvae of gastric gadflies go through three stages of development in the horse's body, and undergo further transformation in the external environment. Larvae of the first stage are 1 mm long. With the help of a pair of sharp hooks, the larvae attach themselves to the mucous membrane of the stomach, mostly in its cardial part, and the duodenum and remain there for prednisone online. After maturation, they pass through the intestinal tract and, together with feces, are thrown out. Larvae of some species linger for some time on the mucous membrane of the rectum in the anus.
After a few days, the mature larvae spontaneously emerge from the eggs and enter the oral cavity. The release of larvae into the external environment is observed in horses in the southern zones in spring, in the central and northern zones - in May, June, and less often in July. On the ground, the larva turns into a chrysalis, and after 1 - 2 months, depending on the temperature of the external environment, a gadfly fly is formed.
Horses become infected with gastrophylles only in the summer, mainly on pastures, during the flight of insects. The most favorable conditions for the development of an adult gadfly and infection of horses are dry, hot weather. Increased moisture has a detrimental effect on gadfly pupae (the latter die as a result of fungal infections). In rainy and cloudy weather, adult gadflies do not fly. Horses that are emaciated and in poor conditions are most susceptible to infection.
Under the influence of hexachlorane, DDT (even at low concentrations - 0.25%), the larvae of prednisone stage of gadflies die on the horse's skin after a few minutes. Subsequently, the larvae enter the stomach and duodenum (intestinal gadfly). With their sharp hooks, they pierce into the thickness of the mucous membrane, injure, ulcerate it and irritate the nerve endings. The affected areas swell and become inflamed. With the accumulation of a large number of larvae (several hundred), disorders of the motor and secretory functions of the stomach can be observed.
The pathogenic effect of parasites is enhanced by the fact that they secrete toxins that cause anemia. Horses have malnutrition, gastroenteritis, often recurring colic, general depression, increased sweating, decreased performance, and sometimes death from progressive exhaustion. In some cases, prednisone pills the lumen of the pyloric part of the stomach and duodenum and even perforate the latter.
In the oral cavity, a significant number of larvae (up to 250 or more) of the red-tailed, eastern and small gastric gadflies are found on the palatine curtain, the root of the tongue, in the mucous and submucosal membranes of the lips, cheeks, and hard palate. In the places of attachment of parasites, the mucous membrane is infiltrated, inflamed, ulcerated, and sometimes necrotic.
Gastrophiles are hard to tolerate emaciated horses. With a weak degree of invasion by gadfly larvae in horses, especially well-fed ones, there may be no clinical signs. Gastrophilia. pathoanatomical changes depend on the period of development of the larvae and their habitat in the body of the animal.
In the initial stage of infection, gastrofiles are diagnosed by the eggs of gadflies found on the skin, and by the larvae found in the mucous membrane.shell of the mouth. In winter, a chemotherapeutic diagnostic method using carbon disulfide, carbon tetrachloride or an allergic test can be applied. The allergen is prepared from the larvae of various types of gastric gadflies (sterile aqueous extract) and used as in ophthalmo-malleinization.
In the stomach and duodenum, with intensive invasions, hundreds of prednisone 20mg are also found attached to the mucous membrane by nests. When the larvae are removed, well-defined crater-shaped wounds up to 4 mm deep remain at the place of their fixation. The mucous and muscular membranes are inflamed and ulcerated. A positive ophthalmic reaction is observed in horses intensively affected by gadfly larvae.
During the flight of gadflies, eggs and larvae emerging from them are destroyed on the animal's skin with 0.25% hexachlorane dissolved in creolin (see p. 295). The emulsion is applied to the entire surface of the horse's body. The larvae die as soon as they hatch from the eggs. Every 10 days, the treatments are repeated until the end of the flight period (September, October). Eggs on the skin are destroyed, in addition, by scraping with a quick movement of a sharp knife, the blade of which is held at an acute angle to the wool.
Gastrophilosis (gastrophilosis) is an entomotic disease caused by larvae of gastric gadflies, manifested by stomatitis, pharyngitis, impaired motor-secretory activity of the gastrointestinal tract, exhaustion and death of animals. Etiology. The causative agents of gastrophilia are gadflies belonging to the genus Gastrophilus, family Gastrophilidae. The following species most often cause the disease. G. intestinalis - a large gastric gadfly, G. veterinus - duodenum, G. pecorum - herbal.