Fateh Singh

Epidemiological, bacteriological and molecular studies on caseous lymphadenitis in Sirohi goats of Rajasthan, India

Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CL), a chronic debilitating disease of goats. In the present study, a total of 575 goats of Sirohi breed on an organized farm situated in the semi-arid tropical region of Rajasthan, India were clinically examined. Pus samples from superficial lymph nodes of 27 (4.7%) adult goats presenting clinical lesions suggestive of CL were collected for bacteriological and molecular analyses. Of these goats, 51.9% yielded C. pseudotuberculosis on the basis of morphological, cultural and biochemical characteristics. A polymerase chain reaction (PCR) assay targeting proline iminopeptidase gene specific to C. pseudotuberculosis was developed that confirmed all 14 bacterial isolates. The specificity of the PCR product was confirmed by sequencing of the 551-bp amplicon in both senses, showing 98–100% homology with published sequences. Thus, overall prevalence rate based on clinical, bacterial culture and PCR assay were found to be 4.7%, 2.4% and 2.4%, respectively. The PCR assay developed in this study was found to be specific and rapid, and could be used for confirmation of CL in goats as an alternative method to generally cumbersome, time-consuming and less reliable conventional methods.

Isolation and adaptation of bovine herpes virus Type 1 in embryonated chicken eggs and in Madin-Darby bovine kidney cell line.

Aim: Objective of the present study was to isolate bovine herpes virus Type 1 (BHV-1) from semen of infected bull and to adapt it onto embryonated eggs and Madin–Darby bovine kidney (MDBK) cell line. Further, the virus was identified by agar gel immunodiffusion (AGID) test. Materials and Methods: Semen samples were collected from five BHV-1 positive bulls previously confirmed for the presence of antibodies against BHV-1 using avidin-biotin enzyme linked immunosorbent assay test. The virus from semen samples was adapted in chorioallantoic membrane (CAM) of 11-day-old embryonated chickens eggs and in MDBK cell line. The presence of BHV-1 in infected CAM and cell culture fluid was confirmed by AGID test. Results: Virus infected CAM showed edema, congestion and thickening at first passage level. Small foci ranged from 1 to 2 mm in diameter, scattered all over the membrane were observed at first passage. More severe changes were observed in CAM after serial passaging. The large pock lesions, round in shape with opaque raised edge and depressed gray central area of necrosis ranged from 3 to 5 mm in diameter were developed at fourth passage. Blind passages in MDBK cell culture were made. The MDBK cell line at second passage level showed characteristic cytopathic effect viz. rounding of cells with shrinkage, followed by aggregation or clumping of cells which progressed rapidly and appeared as “bunch of grapes” at 72 h post inoculation. Few cells become elongated when compared with uninfected controls. A homogenate of CAM with distinct pock lesions and infected cell culture fluid developed precipitation line within 48 h against specific anti-BHV-1 immune serum by AGID test. Conclusion: BHV-1 was easily adapted in CAM of chicken embryos and in MDBK cell line. Virus infected CAM and cell culture fluid showed precipitin band by AGID test.

Seroprevalence of bovine herpes virus type 1 in cattle and buffaloes from Chhattisgarh

Present study was carried out to know the seroprevalence of BHV-1 in the population of cattle and buffaloes from Chhattisgarh, India. A total of 464 serum samples were collected from cattle and buffaloes of different districts in Chhattisgarh. The collected serum samples were screened by Avidin-Biotin Enzyme Linked Immunosorbent Assay kit that recorded an overall seroprevalence of 34.69%. Out of 422 cattle serum samples, 158 (37.44%) were found positive compared to 3 (7.14%) serum samples out of 42 from buffaloes. In different age groups, there was variability in prevalence of BHV-1. Animals above 9 years of age showed the highest seropositivity (45.9%) whereas young animals between 0 to 2 years of age showed the minimum seropositivity (6.89%). Crossbred cattle showed higher seropositivity (40.42%) followed by non-descript cattle whereas indigenous cattle showed the seropositivity of 39.77% and 22.03%, respectively. Murrah, Nagpuri and indigenous buffaloes showed seropositivity of 0%, 3.03% and 50%, respectively. In the present study, seropositivity of 36.53% and 37.56% was recorded in male and female cattle, respectively. Male and female buffalo showed 11.11% and 6.06% seropositivity, respectively. Seropositivity of 45.45% was recorded in animals without clinical signs whereas animals with history of different clinical conditions showed 24.46% seropositivity. Rhinotracheitis, pustularvulvovaginitis, mastitis and balanoposthitis were the main clinical fi ndings associated with the selected in research trial animals.