RESUMO
Marek's disease (MD) and chicken infectious anaemia (CIA) are viral immunosuppressive diseases of poultry caused by the MD virus (MDV) and CIA virus (CIAV) respectively. Despite vaccination against MD, the incidence of the disease in vaccinated poultry flocks in Nigeria persists. However, underlying factors like co-infection with CIAV have not been investigated in the country. This study was designed to investigate possible co-infections of MDV and CIAV in poultry flocks in Nigeria. In 2016, tumorous tissue samples were collected from suspected cases of MD at necropsy in Jos, Plateau State, Nigeria. The samples collected were fixed in formalin for histopathological examination, genomic DNA was extracted from a second part and analysed by polymerase chain reaction (PCR), targeting the meq and VP1 genes of the MDV and CIAV, respectively. The histology results revealed that the cutaneous and proventricular lymphomas were characterized by large numbers of mononuclear cellular infiltrates admixed with heterophils. The PCR results revealed that MDV was detected in 66.7% (16/24), CIAV in 45.8% (11/24), and co-infections of MDV and CIAV were detected in 45.8% (11/24) of the samples analysed. In addition, co-infections of MD and CIA were recorded in 100% (6/6) and 27.7% (5/18) of broilers and layer/pullet' samples respectively. Phylogenetic analysis of the meq gene sequences revealed that the Nigerian MDV clusters with very virulent MDV from Egypt and Italy. While, CIAV sequences were genotype II and genotype III and clustered with CIAVs from Cameroon and China. This is the first report of co-infections of MD and CIA in Nigeria.
RESUMO
Phosphine poisoning is rarely reported in poultry, and its diagnosis is a great challenge for veterinary toxicologists and pathologists. A case of phosphine toxicosis in local, free range chickens is reported. Fourteen dead chickens (age ≥6 months old) were presented to the veterinary clinic for necropsy. The history revealed that the chickens were normally fed with guinea corn grains, but were suspected to have been fed boiled rice laced with poison. The clinical signs observed were ruffled feathers, somnolence, anorexia and high mortality. The disease ran a 2-day course with mortality pattern of four chickens the first day, six overnight and 14 the following day. Necropsy findings showed generalized vascular congestion and haemorrhage in the lungs and visceral organs, with the crop and gizzard filled with guinea corn and rice grains and greenish-yellow faecal material in the intestinal lumen. The presence of widespread congestion and petechial haemorrhages on visceral organs with the microscopic pulmonary congestion, and diffuse intraparabronchial presence of air sac macrophages, strongly suggested an acute toxic cause of death. Chemical tests on the crop contents of the dead chickens were positive for phosphine gas. This report will contribute to a better understanding of the clinical signs and lesions presented in cases of acute phosphide rodenticide exposure in domestic chickens, with a brief review of the forensic literature.