Cross-sectional study of Trichinella spp in pigs in CDR, Nepal using pepsin digestion and ELISA serology.

This epidemiological cross-sectional study was conducted in five major pig-producing districts of CDR, Nepal from November 2006 to April 2007. A total of 576 slaughtered pigs were randomly selected and diaphragmatic crus muscles (n = 551), corresponding sera (n = 487) and sera only (n = 25) were collected from them. Meat samples were examined by pepsin digestion to evaluate for larvae of Trichinella spp. The sera were investigated using ELISA to evaluate for antibodies against T. spiralis. The doubtful and positive sera from the ELISA test were investigated by end-point ELISA, and the Western blot was used for confirmatory diagnosis. Pepsin digestion did not detect the larvae of Trichinella spp. AB-ELISA showed 2 positive and 14 doubtful results, out of 344 sera analyzed. End-point ELISA and the Western blot had revealed that all 16 samples were truly negative. A questionnaire revealed no rodent control (70%), left over feeding practices (65%), dumping of farm waste (82.5%) and uncooked meat was being used as feed (100%). This study reveals that Trichinella spp has a low prevalence.

The epidemiology of Dirofilaria immitis infection in outpatient dogs at Chiang Mai University Small Animal Hospital, Thailand.

Five hundred eighty-nine dog blood samples from the small animal hospital of Chiang Mai University were examined for Dirofilaria immitis prevalence using a microhematocrit tube technique for microfilaria detection. In parallel, a once a month follow-up study on 36 D. immitis negative dogs was conducted to detect the time of acquiring infection in each animal. The diagnostic criteria for the incidence study was based on microfilaria detection or on positive findings against D. immitis antigen using the Witness commercial kit. The estimated prevalence was 18.2% (15-21%; 95% CI). There was no statistical difference between male and female infection rates. The age-specific prevalence of dogs under 2 years old was 6.4%, which was lower than the 2-4 year old group and all the other age groups at a 95% confidence level. In older dogs the prevalence reached 41.5%. Most of the dogs housed outdoors had a statistically higher infection rate than the dogs housed indoors (chi-square = 9.662, 1 df, p = 0.002). Only 109 dogs received chemoprophylaxis resulting in a significantly lower infection rate than in the non-heartworm prevention dogs (chi-square =14.424, 1 df, p = 0.000). The overall incidence density and the incidence during the rainy, cool and hot seasons were 5.2, 6.9, 3.5, and 2.7 animals per 100 animal-months, respectively. The incidence rate ratio between wet/dry, rainy/cool, rainy/summer, and cool/hot seasons were 2.18, 1.98, 2.59 and 1.30, respectively. The 95% confidence interval revealed no difference among seasons. In conclusion, dogs in D. immitis endemic northern Thailand contract infection in about 2 years.

Microbial contamination of pig carcasses at a slaughterhouse in Vientiane capital, Lao PDR.

A cross-sectional study was conducted to determine microbial contamination of pig carcasses at a slaughterhouse in Vientiane, capital of Lao People Democratic Republic (Lao PDR). Between November 2004 and April 2005, 62 pig carcasses were randomly selected. From each carcass, pooled swabs (from "1" prior to and "2" after evisceration) and 25 g of tissue of mesenteric lymph nodes (MLN) were collected. The swab samples were examined for Aerobic Plate Count (APC) and Enterobacteriaceae Counts (EBC) and cultured for Salmonella. The lymph nodes were cultured for Salmonella only. Swabs1 and 2 had mean APC of 4.70 and 4.85 log10CFU/cm2, respectively. These two means were significantly (p = 0.0001) different. The means of EBC were 2.81 log10CFU/cm2 for Swab 1, and 2.98 log10CFU/cm2 for Swab 2. The difference were also statistical significant (p = 0.0001). The frequency of Salmonella isolation from Swab 1 was 46.8%, for Swab 2 was 66.1%, and from mesenteric lymphnodes was 53.2%. Eight different Salmonella serotypes were identified. The most frequent (29.1%) serotype was S. Rissen, followed by S. Anatum (26.2%), S. Derby (18.4%), and S. Elisabethville (8.7%). The other serotypes identified were S. Amsterdam (7.8%), S. Typhimurium (4.9%), S. Agona (2.9%), and S. Enteritidis (1.9%). Results of this study showed the levels of contamination with aerobic bacteria and Enterobacteriaceae were higher than recommended standards, and the carcasses were contaminated with Salmonella.

Seroprevalence of melioidosis in dairy cattle in Chiang Mai Province, northern Thailand.

The seroprevalence of melioidosis in dairy cattle in Chiang Mai Province was investigated using of the indirect hemagglutination antibody (IHA) method. Two hundred and fifty-three samples were tested for serum antibodies to Burkholderia pseudomallei. The samples were from a total population of 8,688 dairy cattle in the province; random sampling, stratified by the location of cattle, was used. The seroprevalence was determined as 2% at 1:40 cut-off value, which was estimated to equate to 0.3% to 3.7% (95% CI). This report of relatively low disease prevalence in the animal population corresponds to other prevalence studies of the agent in the environment and the human population in the region. The prevalence is markedly different to that reported from northeastern Thailand, where the disease is highly endemic.