How to prevent and control swine whipworm disease? A detailed explanation of the key technical points for prevention and control
Swine whipworm disease, also known as swine trichuriasis, 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 has long been a common problem affecting the pig industry. The disease occurs in both intensively raised pigs and free-range pigs, and is especially more likely to occur on pig farms with aging facilities and poor management. Piglets are particularly susceptible to the harm of whipworm, and severe infections often lead to death. Every year the pig industry suffers huge losses because of this disease.
The eggs of swine whipworm are excreted with the feces and develop into infective eggs after about 3 weeks. The infective ability can last as long as 6 years. Pigs ingest infective eggs by eating feed, drinking water or rooting in the soil, and the eggs hatch and develop in the small intestine and cecum of pigs, robbing the pig body of nutrients, inhibiting the pig's mucosal immunity to resident bacteria, triggering necrotizing proliferative colitis, and causing death of the pig.
Clinical symptoms and necropsy lesions: pigs with very mild whipworm disease show no obvious symptoms; in mild cases there is listlessness, slightly elevated body temperature, emaciation, dull coat, and reduced feed conversion rate; in severe infections, the sick pig is extremely exhausted, arches its back, walks unsteadily, has a body temperature as high as 41°C, reduced appetite, generalized pallor, dehydration, and intractable bloody diarrhea, with sloughed intestinal mucosa discharged with the feces, and after 5 days to 6 days it dies from respiratory difficulty and exhaustion. The main necropsy lesions visible are: large numbers of worms adhering to the cecal mucosa, with some worms firmly fixed to the mucosa; at the site of penetration, around the large numbers of worms, inflammatory exudate is secreted to form a fibrinous necrotic membrane, and they gather into round cystic nodules; the intestinal mucosa shows ulcerative necrosis, mainly in the cecum and colon segments, with congestion, hemorrhage and edema.
Diagnosis and treatment
When diagnosing from clinical symptoms whether a pig has whipworm disease, it should be differentiated from swine dysentery. If antibiotic treatment is ineffective, and this is combined with the pathological changes at necropsy, then whipworm infection should be considered. In addition, for a definitive diagnosis, an egg examination can be carried out: weigh about 10 g of feces from the sick pig, break it up, place it in an appropriate amount of saturated saline, stir well, filter, let stand for half an hour, then dip the surface liquid film onto a glass slide, cover with a cover slip and examine under the microscope. If many barrel-shaped, brownish-yellow eggs with egg plugs at both ends are observed, then a diagnosis of whipworm infection can be confirmed.
Generally speaking, levamisole, albendazole, ivermectin, doramectin, oxantel and others all have a certain effect on whipworm. Relatively speaking, however, ivermectin has lower toxicity, is safer and more efficient, and has no cross-resistance with other drugs. From the results the author encountered in treating swine whipworm disease with ivermectin products of different concentrations, it is considered 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., Ltd., whose ivermectin content reaches 0.6%, and which also contains fenbendazole 5%. This is because fenbendazole has a good deworming effect on Trichuris, Ascaris, tapeworms and others. Therefore, if Yigan Erjing is used to treat swine whipworm disease, it can exert a dual killing effect on swine whipworm, especially with a stronger killing effect on the early larvae of whipworm. At the same time, from the recent observations of several large-scale pig farms in the Yuexi area of Guangdong Province using Yigan Erjing to treat swine whipworm disease, for pigs seriously infected with swine whipworm, when the dosage is doubled according to the instructions of Yigan Erjing, a large number of whipworm bodies can be seen being discharged in the feces on the second day of medication, which shows that the deworming effect is obvious and rapid.