Falah Abd Abass(1) and Yahia Ismail Khudhair(2*)
1- Veterinary Hospital, Al-Diwaniyah,
2- Department of Internal and Preventive Medicine, College of Veterinary Medicine, University of Al-Qadisiyah, Al-Qadisiyah, Iraq
Background: Ovine pulmonary adenocarcinoma (OPA), caused by Jaagsiekte sheep retrovirus (JSRV), is a contagious neoplastic disease of sheep characterized by chronic respiratory signs and induce the transformation of secretory epithelial cells of the distal respiratory tract.
Aim: This research aims to perform a clinical, epidemiological and molecular studies with evaluation of some predisposing factors at the herd level of OPA infection in sheep in Al-Qadisiyah province, Iraq.
Methods: a first step of the study was undertaken to evaluate the clinical cases of OPA in naturally infected sheep and correlation with observing respiratory signs. Seventy-five sheep with chronic respiratory signs were examined clinically, and by molecular and sequences analysis. The second step was the epidemiological part that was performed on 195 random-selected animals from 30 flocks, with prevalence rate based on the PCR, and sex, age, and size of flocks was assessed, as well as macro-microscopic features of the neoplastic lung. Deep nasal swabs and nasal secretion were collected from all animals. RNA extraction and RT-PCR were done.
Results: The results showed that 12 (16%) samples were positive to OPA, based on env gene-specific primers. Nucleotides sequences of partial 545 bp of the env gene were shown (0.07-0.12) variation from global strains presented in NCBI database. The prevalence rate of OPA was 21/195 (10.76 %) with PCR. The epidemiological factors analysis showed that there was no effect of sex and herd size on the prevalence rates (P≥ 0.01), whereas the age was significantly affected and the age of 2-4 years was more susceptible (P≥ 0.01). A gross and microscopic examinations were discussed with the confirmation of an OPA infection.
Conclusion: The current study provides useful data about clinical and epidemiological features of JSRV that circulating in sheep of Iraq, and concludes that epidemiological studies and disease control may require multi-diagnostic assays.
Keywords: Adenocarcinoma, OPA, Ovine, Pulmonary, Iraq.