A cross-sectional study of Salmonella in pre-slaughter pigs in a production compartment of northern Thailand.

A cross-sectional study was conducted to determine the prevalence of Salmonella and to associate management factors in fattening pigs in a production compartment of northern Thailand. A total of 194 fecal samples and 166 environmental samples were collected from 22 fattening pig herds for isolation and identification of Salmonella. An additional 427 serum samples were collected from the same herds to determine Salmonella antibodies using ELISA. A questionnaire was used to collect management factors likely to be associated with Salmonella identification. Prevalence of Salmonella in each sample and its confidence interval was adjusted for clustering by herds using linearization technique. A generalized estimating equation was used to determine the odds ratio and significance level for each management factor in a logistic regression model. Salmonella was found in all 22 study pig herds with a fecal sample prevalence of 63% (95%CI: 56-69%) and a serum sample prevalence of 72%. However, isolation results were not significantly different from ELISA results. The most isolated serotype was Salmonella Rissen (49%) followed by Salmonella Typhimurium (19%), Salmonella Stanley (12%) and Salmonella Weltevreden (4%) being significantly different in the different specimens collected (p=.024). The final logistic regression model with isolation results as outcome showed that medium herd size (OR=2.32, p=0.003), quality certification according to the Department of Livestock Development standard (OR=1.88, p=0.000), use of effective microorganisms (OR=1.51, p=0.022), slurry waste management (OR=2.17, p=0.000) and less number of pigs per pen (OR=1.12, p=0.000) were significantly associated with positive Salmonella isolation; with positive ELISA results, however, only the use of effective microorganisms was significantly associated (OR=2.63, p=0.011).

Seroprevalence of Trichinella in slaughter pigs in Kathmandu Valley, Nepal.

The aim of the present study was to determine the Trichinella seroprevalence in slaughter pigs in Kathmandu Valley, Nepal. Serum samples were obtained from 400 pigs at 4 major slaughterhouses and tested for Trichinella antibodies by ELISA using larval excretory-secretory (E/S) antigen. Four were positive and one was equivocal, giving a Trichinella seroprevalence of 1% (95% CI: 0.27 - 2.54). On titration, all positive and equivocal samples had titers greater than 1:80. Upon re-examination the equivocal sample failed to give a positive ELISA result. The pigs were from four major areas of Nepal, Kathmandu Valley, eastern Nepal, Terai and adjoining areas of the valley. Positive results were found from only Kathmandu Valley and adjoining areas. There was no significant difference in the prevalence between areas (p = 0.43). All four positive samples were from indoor managed pigs. The Trichinella seroprevalence determined in this study deserves a direct demonstration of the parasites for proof of the presence of Trichinella in Nepal and to discover the species and infection sources.

Metaphylactic deworming program for buffalo calves (Bubalis bubalis) in North-East Thailand.

One hundred newborn swamp buffalo calves (Bubalis bubalis) from three villages in North-East Thailand were divided equally into treatment and control groups. Treated calves received two doses of a piperazine/thiabendazole mixture (196.6 and 50 mg/kg bodyweight respectively) at three, and again at ten weeks of age. Control calves received placebo treatments at the same times. Egg excretion rates for the roundworms Strongyloides papillosus and Toxocara vitulorum were recorded as high as 85% and 58% respectively during the first three months of life. During the trial period, four calves in the treated group died and one was treated for coccidiosis, compared to seven deaths and nine additional anthelmintic treatments required in the control group. All calves that either died or required additional anthelmintic treatment showed signs of severe enteritis, anorexia and emaciation that was attributed to parasitic infestation. Calves receiving emergency anthelmintic treatment all recovered uneventfully. All except four of the calves that died or became sick did so between 25 and 40 days post partum, with the remainder developing clinical signs of parasitosis before day 50. There was no difference in weight gains between treated and untreated calves over the trial period (16 weeks). Thus, the advantage of anthelmintic treatments as described at three and ten weeks of age in buffalo calves under village conditions was seen as a reduction in the combined morbidity/mortality rate from 32% to 10% (P less than 0.05). From the pattern of infection observed in this study it is suggested that further gains could be made by giving the second treatment at six (instead of ten) weeks of age, and by increasing the dosage of anthelmintic used.

Trypanosoma evansi infection in buffaloes in North-East Thailand. II. Abortions.

By exclusion of other possible aetiological agents, strong circumstantial evidence is presented of Trypanosoma evansi infection being the cause of late gestation abortion and stillbirth in buffaloes.

Trypanosoma evansi infection in buffaloes in north-east Thailand. I. Field investigations.

Clinical, parasitological and serological findings of Trypanosoma evansi infections in buffaloes (Bubalis bubalis) from north-eastern Thailand are reported. The overall infection rate was found to be around 20% with a distinct peak of acute infections during the rainy season. The disease is aggravated by normally well tolerated concomitant infections such as liver fluke infestations and by other stress factors.