猪痢疾的综合防控措施

猪痢疾是由猪痢疾密螺旋体(Treponema hyodysenterisa)引起的一种以黏液性、出血性下痢为特征的猪肠道传染病。猪痢疾最早于1921年被报道,直到1971年才确定为猪痢疾短螺旋体(Brachyspira hyodysenterisa)感染所致~([1])。猪痢疾一旦侵入猪群,不易根除。在流行初期,以急性出血性下痢为主,流行中后期,以亚急性和慢性黏液性下痢为主~([2])。7～12周龄仔猪易感,发病率可高达70%,病死率为30%～60%,发病率和死亡率高于成年猪~([3])。由于猪痢疾的存在,导致猪只生长缓慢,料重比升高甚至出现死亡,增加养殖成本,给养猪业带来巨大经济损失~([4])。     

Lymphocyte stimulation in swine dysentery

In lymphocyte stimulation studies of pigs affected with swine dysentery (SD) all of the pigs gave significant response (P < 0.05) to soluble antigen from $\text{Treponema}$$\text{hyodysenteriae}$. Swine infected with virulent or attenuated $\text{T.}$$\text{hyodysenteriae}$ gave significant lymphocytic response 3 or 6 weeks after infection; uninfected pigs did not give a similar lymphocytic response. The delayed hypersensitivity (DH) skin test, in which soluble $\text{T.}$$\text{hyodysenteriae}$ antigen preparation was used, detected only 3 out of 14 SD-affected swine. The lymphocyte stimulation assay by detection of protein synthesis may offer a rapid, reliable test for the diagnosis of SD within herds suspected of being affected.     

Passive protection of segmented swine colonic loops against swine dysentery

Swine-ligated loops were used to demonstrate passive protection against swine dysentery. Loops inoculated with immune sera containing complement and with homologous Treponema hyodysenteriae were normal at necropsy. Loops inoculated with heat-inactivated immune sera and heterologous T hyodysenteriae were not protected. Loops inoculated with heat-inactivated immune sera and homologous T hyodysenteriae were partially protected. Positive control loops inoculated with isolate B204 (88%) or B234 (44%) T hyodysenteriae and normal sera developed lesions typical of swine dysentery, whereas negative control loops inoculated with nonexposed sera only were normal.     

盐酸沃尼妙林预混剂对猪痢疾的临床疗效试验

沃尼妙林(valnemulin)是新一代截短侧耳素(pleuromutilin)类半合成抗生素,属二萜烯类,与泰妙菌素属同一类药物,是动物专用抗生素.主要用于防治猪、牛、羊及家禽的支原体病和革兰阳性菌感染.1999年由欧共体批准用于预防与治疗由猪痢疾短螺旋体感染引起的猪痢疾和由肺炎支原体感染引起的猪地方性肺炎[1].     

The effect of monensin against swine dysentery

The use of monensin sodium against naturally transmitted swine dysentery was evaluated in 4-week-old piglets, with an average weight of 8 kg, over a period of 112 days. Three treatments were compared using between two and four pens per treatment and 12 pigs per pen. Monensin was administered via the feed, either immediately post weaning to four pens of pigs (T1), or after 12 days (T2, two pens). The T1 group received monensin at the rate of 100 ppm (days 0-56), 50 ppm (days 57-84) and 25 ppm until the end of the trial. In the other group monensin was given at 100 ppm (days 12-84) and at 50 ppm (days 85-112). Unmedicated feed was given to two pens (T3). The continuous administration of monensin from weaning was effective in the control or prevention of swine dysentery. A significant (P less than 0.05) improvement, in comparison with the other two groups, was observed in terms of mortality, diarrhoea score, average daily gain (ADG) and feed conversion ratio (FCR). There was a reduction in mortality, diarrhoea score/days and an improvement in growth performance parameters in pigs treated with monensin after the disease had been established, with ADG and FCR values significantly (P less than 0.05) different compared with the untreated controls.     

3-Acetyl-4'-isovaleryl tylosin for prevention of swine dysentery

The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4'-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4'-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigations on Brachyspira--diagnostic and therapeutic strategies in swine dysentery

The infectious agent of swine dysentery, Brachyspira (Br.) hyodysenteriae, seems to be widespread in German pig herds. Due to different reasons the eradication is increasingly difficult. Not only the success of therapeutic procedures but also the possibilities of diagnostics are unsatisfactory. Although only the bacteriological investigation of faeces or intestinal probes by culture techniques allows the typing of Brachyspira strains and the testing of drug resistance, however, the rate of false negative results is relatively high. In comparison with the cultural method an easy, prompt and cheap immunofluorescent test (IFT) resulted in a good sensitivity (90%). The higher rate of negative results by culture techniques can not be attributed to a lower specificity of the IFT, but to an insufficient transport of samples to the laboratory. The IFT therefore has to be considered as a valuable supplement to the cultural diagnostic of Br. hyodysenteriae. It is absolutely necessary to establish strategies in eradication of swine dysentery which result in pig breeding herds free of Br. hyodysenteriae. Only weaner pigs which are reliable free of this germ guarantee a fattening period sufficiently free of swine dysentery. The principles of different measures in effective eradication are described.