Diagnostic Methods and Treatment Measures for Swine Trichuriasis
Swine trichuriasis, also known as swine whipworm disease, is an internal parasitic disease caused by Trichuris suis parasitizing the cecum of pigs. The disease is widely distributed and can occur in all four seasons, and it has long been a common problem affecting the @#@227@#@ industry. The disease can occur in both intensively raised pigs and free-range pigs, and is especially likely to occur in pig farms with aging facilities and poor management. Piglets are particularly susceptible to the harm of whipworms, and severe infections often lead to death. Every year the pig industry suffers huge losses due to this disease.
The eggs of Trichuris suis are excreted with the feces, and after about 3 weeks they develop into infective eggs, and their infectivity can last as long as 6 years. Pigs ingest infective eggs by eating feed, drinking water or rooting in the soil. The eggs then hatch and develop in the small intestine and cecum of pigs, robbing the pig's body of nutrients, suppressing the pig's mucosal immunity to commensal bacteria, triggering necrotizing proliferative colitis, and leading to the death of the pig.
Clinical symptoms and necropsy lesions: Pigs with the mildest cases of trichuriasis show no obvious symptoms; in mild cases, the pigs are lethargic, with a slightly elevated body temperature, emaciated body shape, dull hair coat, and reduced feed conversion rate; in severe infections, the sick pigs are extremely debilitated, with an arched back, staggering gait, body temperature as high as 41 degrees C, loss of appetite, generalized pallor, dehydration, and intractable bloody diarrhea, with sloughed intestinal mucosa discharged with the feces, and after 5 days to 6 days they die of exhaustion due to difficulty breathing. The main necropsy lesions visible are: a large number of worms adhering to the cecal mucosa, with some worms firmly attached to the mucosa, and at the sites of penetration, a large amount of inflammatory exudate secreted around the worms forms a fibrinous necrotic membrane, which aggregates into round cystic nodules; the intestinal mucosa shows ulcerative necrosis, mainly in the cecum and colon segments, along with congestion, hemorrhage and edema.
Diagnosis and treatment
When diagnosing from clinical symptoms whether a pig has trichuriasis, it should be differentiated from swine dysentery. If antibiotic treatment is ineffective, and this is combined with the pathological changes seen at necropsy, then trichuris infection should be considered. In addition, for a definitive diagnosis, an egg examination can be carried out: weigh out about 10 g of the sick pig's feces, break it up, place it in an appropriate amount of saturated saline, stir evenly, filter, and let it stand for half an hour, then dip up the surface liquid film and place it on a glass slide, cover with a coverslip and examine under a microscope. If many barrel-shaped, brownish-yellow eggs with plugs at both ends are observed, then trichuris infection can be definitively diagnosed.
Generally speaking, levamisole, albendazole, ivermectin, doramectin, oxantel and others all have a certain effect against whipworms. But relatively speaking, ivermectin has lower toxicity, is safer and more effective, and has no cross-resistance with other drugs. From the results the author encountered in treating swine trichuriasis with ivermectin products of different concentrations, it is believed that products with an ivermectin content of 0.5% or more should be selected for treatment. It is recommended to choose Yigan Erjing produced by Hengfengqiang Animal Pharmaceutical Co., which has an ivermectin content of 0.6% and also contains 5% fenbendazole. This is because fenbendazole has a good deworming effect against Trichuris, Ascaris, tapeworms and others. Therefore, if Yigan Erjing is used to treat swine trichuriasis, it can exert a dual killing effect on Trichuris suis, and the killing effect is especially stronger against the early larvae of whipworms. At the same time, from recent observations of the use of Yigan Erjing to treat swine trichuriasis in several large-scale pig farms in the western Guangdong region of Guangdong Province, for pigs severely infected with Trichuris suis, when the dosage was doubled according to the instructions of Yigan Erjing, a large number of whipworm bodies could be seen being discharged in the feces on the second day of medication, which shows that the deworming effect is obvious and rapid.