Pathological studies on wild pigeons (Columba livia var domestica) and crows (Corvus cornix)

Abstract

Free-living birds, including migratory and non-migratory species, can become long-distance vectors for a wide range of microorganisms that can be transmissible to humans, animals and poultry. Our study aimed to give a spotlight on the pathological affections that could be found in wild pigeons and crows and illustrate the potential role of those wild birds in transmitting viral, bacterial and parasitological pathogens to various livestock in Egypt especially poultry industry as well as illustrate the zoonotic importance of those species of birds. Fifty birds of each apparently healthy wild pigeons and crowswere collected from non-urban areas in Egypt including; (6Th ofOctober city and 10Th ofRamadan city), during the hunting seasons from September, 2015 to July, 2016.The birds were transferred to the laboratory and were left for 24 hours for observation of anyabnormal clinical signs and external examination. Blood samples were collected and profound P.M examination was carried out. Specimens were collected from trachea, lungs, GIT, liver, pancreas, cecal tonsils, kidneys, spleen, bursa, heart, brain and pectoral muscle. The collected specimens were divided into 3 parts for histopathological, bacteriological as well as virological investigations. The gross pathology was variable, was not specific and no conspicuous lesion was related to a particular locality. The observed histopathological lesions in both species of birds were numerouswith variable incidences and included; tracheitis (in pigeons), lungs of crows and pigeons showed acute interstitial pneumonia, verminous pneumonia and anthracosis in addition to acute fibrinous bronchopneumonia, granulomatous reaction and acute bronchitis in pigeons. The lesions in gastrointestinal tracts of both species included; inflammation of proventriculus and acute enteritis, parasitic infestation in intestinal lumen (in pigeons), but in crows parasitic cross sections were detected in proventriculus and gizzard. The liver of both species showed; acute hepatitis, cholangitis and pericholangitis, parasitic infestation in hepatic parenchyma, in the bile ducts and in blood vessels or in all sites together. Pigeons' liver showed granulomatous reactions. Kidneys of both species showeddiffuse or focal interstitial nephritis with variable degrees of severity as well as fluid-filled cystic spaces in kidneys of pigeons. Heart lesions in pigeons were focal areas of necrosis and thinking of blood vessels walls with perivascular oedema.The immune organs showed variable degrees of lymphocytic depletions, the bursa of some pigeons had cystic spaces and that of one crow had parasitic cross sections. Brains of both species showed neuronal degeneration, neuronophagia, and gliosis and purkinje cell necrosis.Bacteriological isolation revealed E. coli O157, Klebsiella, Enterobacter, Citrobacter, Shegilla and Pseudomonas in both species, Salmonella only isolated from crows. While, virologicalisolation revealed H9N2 which isolated from both species and PPMV-1 which isolated only from pigeons.

Key words:Wild pigeon's, Crows, Histopathology, H9N2, PPMV-1, Enterobactereace, Pseudomonas, Shiga toxin producing E. coli.