Evaluation of Analytical Sensitivity of Sdf I based PCR and Sandwich ELISA for Salmonella Enteritidis detection and On-Farm prevalence in Punjab, Pakistan

Salmonella Enteritidis (SE) is a dominant serotype among non-typhoidal Salmonella which renders poultry products unsafe for human consumption. Due to frequent reporting of egg associated outbreaks, broiler breeder flocks are understudied although farm environment present supporting conditions for the growth of SE. In this study, two rapid detection techniques for SE were compared in terms of analytical sensitivity and the extent of SE contamination in broiler breeder farm environment was determined. Analytical sensitivity as limit of detection (LOD) was evaluated quantitatively for serotype specific PCR based on amplification of Sdf I gene and a commercially available sandwich ELISA for antigen detection. In triplicate experiments, tenfold serial dilutions of SE were prepared and tested with each technique. Using pure cultures, analytical sensitivity of PCR and ELISA were found to be 18.6 CFU/ml and 2.77×105 CFU/ml respectively. PCR (LOD, log 1.2) was found to be more sensitive and rapid than ELISA (LOD, log 5.4). Environmental swab samples (n = 260) were collected from 22 hen houses representing 8 broiler breeder farms located in and around Lahore and Sheikhupura districts of Punjab province. From each hen house swab samples were collected from litter, nests, feeders, drinkers, fans, pads, ceiling, walls and walkways. Following selective enrichment, pooled swab samples were subjected to PCR. Results showed that 36.3 % (8/22) hen houses were detected positive for SE. These findings suggest improvement in farm biosecurity measures and advocate implementation of integrated Salmonellosis control programs in broiler breeder houses to minimize carcass contamination.(AU)

Molecular characterization and pathology of field isolates of foot-and-mouth virus in Swiss albino mice / Caracterização molecular e patologia de isolados de campo do vírus da febre aftosa em camundongos albinos suíços

Foot-and-mouth disease is responsible for severe economic losses to the livestock industry of Pakistan. This study aimed to use Swiss albino mice as a cost-effective experimental animal model to study different immunological and histopathological aspects of FMDV instead of natural targeted species like cattle. After isolation of field isolates FMDV on BHK-21 cell line, biological titer of the virus and mice infectious dose50 was calculated. Virus was injected in 45 Swiss albino mice (group A) through intraperitoneal route. The gross, histopathological and immunopathological lesions in heart, trachea and lungs were recorded at different day's intervals. Histopathologically, the heart showed congestion, hemorrhages and necrosis of cardiac muscles. Trachea showed deciliated epithelium and lungs showed hemorrhages, bronchial edema and alveolar emphysema. Immunohistochemical studies revealed the presence of virus in cardiac muscles, tracheal and bronchial epithelium and alveolar lumen. The findings evoked a thought that laboratory animals could be an alternative to large animals to meet budget limitations for further research on foot-and-mouth-disease.

A febre aftosa (FMD) é responsável por graves perdas econômicas para a indústria pecuária do Paquistão. Este estudo teve como objetivo usar camundongos albinos suíços como um modelo animal experimental de baixo custo para estudar diferentes aspectos imunológicos e histopatológicos do FMDV em vez de espécies naturais como o gado. Após o isolamento dos isolados de campo do FMDV na linhagem celular BHK-21, calculou-se o título biológico do vírus e a dose infecciosa dos camundongos50. O vírus foi injetado em 45 camundongos albinos suíços (grupo A) por via intraperitoneal. As lesões macroscópicas, histopatológicas e imunopatológicas no coração, traqueia e pulmões foram registradas em diferentes intervalos de dias. Histopatologicamente, o coração apresentava congestão, hemorragias e necrose dos músculos cardíacos. A traqueia apresentava epitélio deciliado e os pulmões apresentavam hemorragias, edema brônquico e enfisema alveolar. Estudos imuno-histoquímicos revelaram a presença de vírus em músculos cardíacos, epitélio traqueal e orçamentárias para pesquisas adicionais sobre a febre aftosa