Seroprevalence of toxoplasmosis in a district of Assam, India.

Toxoplasmosis is one of the important zoonoses of man and has been known to cause serious problems particularly in females. A study on seroprevalence of toxoplasmosis was undertaken amongst the human population in Assam to determine the level of exposure of the population to the infection by using commercial ELISA kits. Of the 241 sera belonging to different age groups, sex and religion and having varying levels of exposure to the animals examined, 23 (9.54%) were positive for toxoplasmosis. No significant difference in the prevalence amongst males and females was observed. Some occupational groups like veterinarians, pet keepers and farmers were found to infect more frequently. Although the overall prevalence rate of toxoplasmosis was relatively low, higher prevalence rate of toxoplasmosis amongst the exposed groups warrants due care by these groups when they are handling the animals.

Isolation, phage typing and antibiogram of Salmonella from man and animals in northeastern India.

BACKGROUND AND OBJECTIVE: Salmonella is an important zoonotic pathogen and its prevalence in the animals acts as a continuous threat to man. The present study was carried out to report the isolation along with the serotypes, phage types and antibiogram pattern of Salmonella among man, livestock and poultry in the northeastern India. METHODS: A total of 654 samples from diarrhoeic livestock and humans were processed for the isolation of Salmonella. All the isolates were subjected to antibiogram studies against 15 antimicrobials. Representative isolates of S. Typhimurium and S. Enteritidis were phage typed. RESULTS: Ninety five isolates of Salmonella enterica belonging to 5 serotypes- S. Typhimurium, S. Enteritidis, S. Gallinarum, S. Paratyphi B and S. Bareilly were obtained with an overall prevalence rate of 14.40 per cent. S. Typhimurium isolates were distributed among four phages- DT003, DT004, DT096 and DT193 and all the S. Enteritidis isolates belonged to a single phage type, PT13a/7. Interspecies sharing of the phages was observed. Norfloxacin, enrofloxacin, gentamycin and ciprofloxacin were most effective, whereas, doxycycline, ampicillin, amoxycillin and tetracycline were relatively less effective. INTERPRETATION AND CONCLUSION: Our findings showed that three of the five serovars as well as some of the phage types of these serovars were shared by animals and humans indicating the zoonotic potential of the organism. Thus, it is imperative that salmonellosis control measures adopted for humans should give adequate importance to its control in the animals particularly their products.

Occurrence of sopE gene and its phenotypic expression among different serovars of Salmonella enterica isolated from man and animals.

Salmonella pathogenesis is a complex phenomenon and a Type III secretion system plays a central role in the development of Salmonella-induced enteritis. One such Type III secretion protein is Salmonella outer protein E (SopE). Prevalence of sopE gene and its phenotypic expression (SopE protein) among different serovars of Salmonella enterica isolated from man and animals were investigated. Of 305 strains of S. enterica belonging to 11 serovars tested for the presence of sopE, 130 strains belonging to three serovars viz., Enteritidis, Gallinarum and Virchow were found to carry sopE gene irrespective of their source of isolation when tested by PCR amplification technique using its specific primers. Of these 130 strains, 112 strains were found to express SopE protein phenotypically as detected by Dot-ELISA using SopE antibody. Among the different serovars tested only serovars Gallinarum, Enteritidis and Virchow expressed SopE protein phenotypically in vitro. Role of SopE protein in pathogenesis of salmonellosis has been discussed.

Distribution of virulence genes in Salmonella serovars isolated from man & animals.

BACKGROUND & OBJECTIVES: Pathogenesis of Salmonellosis depends upon a large number of factors controlled by an array of genes that synergise into the actual virulence of Salmonella. A study was undertaken to observe the distribution of three such genes, namely, Salmonella enterotoxin (stn), Salmonella Enteritidis fimbrial (sef and plasmid encoded fimbrial (pef genes, among different serovars of Salmonella enterica isolated from man and animals. METHODS: A total of 95 isolates belonging to S. Typhimurium (51), S. Enteritidis (36), S. Bareilly (3), and S. Paratyphi B (5) serovars were subjected to polymerase chain reaction (PCR) assay for the detection of stnl ssf and pef genes using their specific primers and the PCR products were analysed by 1 per cent agarose gel electrophoresis for the presence of the respective genes. RESULTS: Varying distribution pattern of these genes was observed amongst the isolates. While, stn was found in all the 95 strains, sef was found only among the S. Enteritidis isolates. The pef gene was found to be absent in 10 isolates including the three S. Bareilly isolates. INTERPRETATION & CONCLUSION: Findings indicated that the stn gene is widely distributed among Salmonella irrespective of the serovars and source of isolation. However, the sef gene appears to be serovar specific. Since the stn gene is found in all the isolates, it can be a viable target gene to explore the possibility of direct detection of Salmonella from samples from biological sources.