The larva that has developed from the egg that has emerged becomes invasive after two molts. It is very mobile and, unlike previous species, does not wait to be swallowed, but can actively crawl from a wet blade of grass onto a lying lamb or calf and, piercing its skin, penetrate into the animal’s tissues. The larva is introduced into the intestine by the blood stream and already settles here for permanent residence, feeding and growing up. Sick animals are treated with carbon tetrachloride and phenothiazine.
Sheep’s dictyoculus and cow’s dictyoculus are rightly called the scourge of animal husbandry. The adult parasite usually settles in huge quantities in the bronchi and trachea of young animals — lambs and calves. Here, the female worms fertilize and produce a huge number of eggs. The eggs are coughed up into the mouth and swallowed with saliva. In the small intestine of the host, these eggs hatch into larvae, which are then released into the faeces. The presence of larvae in the external environment is necessary. Without this, they do not acquire the ability to infect new animals — that is, they cannot become invasive. A lamb or calf (adults are less likely to get sick) ingests invasive larvae in a pasture with food. The larvae enter the bloodstream through the wall of the digestive tract and eventually enter the lungs. Here, the parasites, bursting the blood vessels, enter the lumen of the pulmonary vesicles, move into the trachea and bronchi, where they grow into adult worms, which have a length of up to 150 in sheep and up to 70 millimeters in calves. The first phase of the course of dictyoculus—induced disease is intestinal: diarrhea and loss of appetite. Then the pulmonary phase develops. The animals suffer from a debilitating painful cough – the parasites irritate the respiratory tract. In the affected flocks, the mortality rate of lambs reaches 75 percent, calves up to 50 percent. It is difficult to fight this parasite. Sick animals are treated with inhalations of aluminum iodide aerosol, affecting the parasite in its pulmonary stage. It is rational to process the entire herd twice — in spring and autumn. For prevention, the schedule of changing pastures is important.
In ruminant lung parasites belonging to the genus protostrongilus, the life cycle differs from that of dictyocauluses in that the larva that leaves the sheep or cow and comes out becomes invasive only in the body of the ingested mollusk (intermediate host). Cattle become infected in the pasture by swallowing a freshwater or land snail stuffed with larvae with grass. The registration process is quick and simple, taking only a few minutes to complete all steps. During this crucial phase, remember to use 1xbet promo code for registration in the designated field, which you can find on the registration form whether you choose one-click, phone, or email sign-up. This action provides a 200% welcome bonus up to €/$130 on your first deposit, usable across all sports sections and casino games on the platform. The one-click registration automatically generates a username and password, while phone registration requires SMS verification.
Advertisement
