Pathological conditions affecting the domestic pigeons (Columba livia) in Jammu region

In the present study, a total of approximately 3980 domestic pigeons belonging to various pigeon fanciers were screened for clinical cases of disease affection. Twelve areas were selected for the survey, out of which ten were in the RS Pura sector and two were within the Jammu city limits. Out of the population of pigeons observed, approximately 608 birds were found to be clinically affected with some form of clinical disease or other, based on flock history, clinical examination and laboratory investigation. The overall estimate of disease prevalence amongst pigeons was observed at 15.28%, with the highest prevalence in Banota area and least in Ranbir Singh Pura town area. Mortality was accounted only for birds that were accessed for necropsy examination and 60 pigeons were necropsied with overall mortality of 1.51% between July 2015 - June 2016. The predominant cause of death diagnosed was due to Haemoproteus columbae induced pneumonia and hepatitis (45.00%); Newcastle disease (20.00%); mycotoxicosis (13.33%); aspergillosis (8.33%); traumatic injury (6.67%); pigeonpox (3.33%); Salmonellosis and colibacillosis (1.67% each). Haemoproteosis (45.00%; 27/60) caused a high mortality amongst pigeons with severe and consistent hepatic and pneumonic lesions. Lung and liver tissue revealed various stages of protozoan parasite development and apparently was target organs of schizogony within vascular endothelium and accompanied by severe vascular and tissue reaction. A typical round cell granuloma could be seen around blood vessels. Newcastle disease (ND) infection was manifested predominantly in a severe neurological form with characteristic malacia and demyelination of brain parenchyma. Satellitosis, microgliosis and neuronophagia were also seen. Serum samples collected from 10 out of 12 affected pigeons were found positive by haemagglutination inhibition test with high titres (1/32 to 1/64) of circulating antibodies. Two outbreaks of mycotoxicosis (13.33%; 8/60) were suspected amongst pigeons, with typical hepatic degeneration and lesions. Concurrently, renal degenerative lesions were also seen. Aspergillus flavus could be isolated and differentiated from feed grains. Tissue and grain samples were positive for Aflatoxin B1, while as citrinin and ochratoxin was also found in the feedgrains. Presence of aflatoxin in feeds and fungal cultures were also detected by UV light. In an outbreak of aspergillosis (8.33%; 5/60) severe granulomatous pneumonia and systemic affections of tissues with typical nodules were seen. Microscopically, both an encapsulated lymphohistiocytic granulomatous pneumonia and a non-encapsulating invasive infection were seen. Sporulating elements invading the bronchial mucosa and lumen of the airways was typical. Aspergillus fumigatus organsims were also isolated from the lesions. Four birds were found to have died due to fatal traumatic (6.67%; 4/60) and haemorrhagic injury caused by infighting and preyed on by raptors. Pigeon pox (3.33%; 2/60) was easily recognizable with scabby lesions on the unfeathered parts of the. Two mortalities amongst young birds with both cutaneous and severe diptheritic form of the disease were observed. Typical lesion was characterized by ballooning degeneration of keratinocytes containing eosinophilic A-type intracytoplasmatic inclusions. Isolation of Pigeon pox virus revealed pock lesions on the chorioallantoic membrane (CAM) on 14th day developing chicken embryo. Colibacillosis (1.67%; 1/60) and salmonellosis (1.67%; 1/60) was diagnosed in one bird fatalities each and confirmed with isolation of bacteria, biochemical tests and morphological characteristics. Both live and dead pigeons were examined externally revealed numerous ectoparasites and as many as six species of ectoparasites were collected from the pigeons or their lofts. They included the chewing lice Columbicola columbae, small pigeon louse Campanulotes bidentatus, pigeon flatfly or louse fly Pseudolynchia canariensis, mite Psoroptes sp. and a flea tentatively identified as Ctenocephalides sp. Besides, there were many mosquito and fly species which were not identified. Gastrointestinal parasites included the tapeworm Raillietina sp. (25%; 15/60), the large roundworm Ascaridia sp. (5%; 3/60) andthe hairworm Capillaria sp. (6.67%; 4/60 Besides, Eimeria sp (58.3%; 35/60), Cryptosporidia sp. (50.0%; 5/10) and Haemoproteus columbae gametocytes (26.6%; 8/30) were recorded. Both macrogametocytes, microgametocytes, immature stages, extra-corpuscular forms could be detected in the blood. Haematological studies of Haemoproteus infected and non-infected pigeons revealed a significant decrease (P<0.05) in Hb, PCV and eosinophilia in diseased birds. Twenty-four pooled faecal samples examined from six select villages of Jammu district in the four recognized seasons (Monsoon, post-monsoon, winter, summer) revealed presence of different parasitic ova with Ascarid eggs least prevalent whereas, Eimeria sp. was highest. Capillaria eggs were relatively abundant with no particular seasonal prevalence. Raellietina sp. was the most common metazoan enteric infestation but its observed prevalence apparently was lowered in the peak summers.