Sheep-nosed fly maggot disease is a disease caused by the parasitization of the larvae of the sheep's nose and nearby cavity sinuses. The harm to sheep is heavy, and the harm to goats is light.
The development of the sheep nose fly needs to go through three stages: larval, pupa and adult. Adult worms appear in May to September every year, after male and female mating, males die quickly, females fly to the sheep nose in a sharp and sudden movement during the day when there is sunlight, the larvae are born in the sheep nostrils or around the sheep nostrils, the first stage of larvae produced is very active, crawling into the nasal cavity and fixing on the nasal mucosa with its pre-mouth hook, and gradually moving deep into the nasal cavity, reaching the frontal sinus or sinuses, and developing into the third stage larvae after two metamorphosis. The larvae parasitize in the nasal cavity for about 9-10 months, and by the following spring, the mature tertiary larvae migrate from the deep part of the nasal cavity to the shallow part, and when the affected sheep sneezes, it is sprayed out of the nostrils, and the tertiary larvae pupate in the surface of the soil or in the sheep dung, and feather into adults after 1-2 months.
After the sheep nose fly larvae enter the sheep nasal cavity, frontal sinus and sinuses, in the process of migration, due to the small spines on the body surface and the damage to the mucous membrane of the anterior hook of the mouth, rhinitis can be seen in the sheep, the nasal fluid is initially serous, followed by mucus or purulent, sometimes mixed with blood. When a large amount of nasal leakage dries up and forms a hard scab around the nostrils, it makes it difficult for the sheep to breathe. Sick sheep show uneasiness, sneezing, shaking their heads frequently, rubbing their noses, puffy eyelids, tears, decreasing appetite, and increasing emaciation. Clinical manifestations can persist for several months depending on the developmental period of the larva in the nasal cavity. Usually the infection is soon acute, gradually improves, and becomes more acute in the late stages of larval parasitism. Sometimes when individual larvae enter the cranial cavity and damage the meninges or spread to the meninges due to inflammation of the sinuses, neurological symptoms can occur, and the sick sheep manifest themselves as dyskinesia, rotational movements, head bent to one side or paralysis, and finally the sick sheep loses appetite and dies of extreme exhaustion.
The control of this disease should be based on the elimination of stage I larvae as the main measure. The method is as follows: Enemy Worm or Enemy Worm Ointment. During the fly season, 10% dichlorvos or 1% dichlorvos ointment can be applied around the nostrils of sheep; avermectin. Take 0.2 mg per kilogram of body weight, once subcutaneously; Refined 60 g of dichlorvos, dissolved in 31 ml of distilled water and 31 ml of 95% alcohol, at 0.4 mg per kg of body weight, once intramuscular injection, 50 kg of body weight above 2.5 ml; dichlorvos. Sheep at 5 mg per kilogram of body weight, formulated as water emulsion, once a day, for 2 days; the liquid is sprayed nasally. It can be sprayed in the nostrils of 0.1%-0.2% octyl thiophos, etc.; smoke method. Commonly used for mass control, it should be carried out in a closed enclosure or tent, according to the indoor space per cubic meter of 80% of the chlorhex 0.5-1 ml, heating or high-pressure spray, spray time of 15 minutes to kill the first stage of larvae; chlorocyan salamide. 5 mg intratherapy dose per kilogram of body weight, or 2.5 mg subcutaneously, can kill larvae of all stages.
Source Jilin Rural Daily
Planned by Meng Fanjie, Shi Wei, Han Tieying
Edited by Chi Ruibing