Características da cinomose em cães naturalmente infectados em Belo Horizonte (2012-2014): aspectos clínico-neurológicos e sua correlação com a carga viral e apoptose encefálicas

Abstract

Canine distemper is one of the most important infectious diseases in vaccinated and non vaccinated dogs with high rates of morbidity and mortality. Is this study, two experiments were performed to evaluate canine distemper virus infection characteristics, genetic apoptotic proteins expression and virus load quantification and correlation and the relation with neurological signs in Belo Horizonte, MG, Brasil, between 2012-2014. The first evaluated the epizootiological pattern of dogs naturally infected with canine distemper in the Veterinary Hospital of UFMG. It was observed that the disease is more frequent in adult (1-6 years old) and in non-vaccinated dogs, without statistic difference in sex or season of the year between infected animals. The extraneural and neural signs were varied, with a predominance of gastroenteric and respiratory manifestations and myoclonus and motor deficit, respectively. Haematological indices of 44 dogs revealed, in most cases, nonregenerative anemia, lymphopenia e low counts of Sinegaglia-Lentz corpuscles. Analysis of cerebrospinal fluid in 16 dogs showed that, in most cases, protein levels increasead associated with lymphocytic pleocytosis. The immunochromatography test with cerebrospinal fluid samples was positive in 100% in animals with neurological signs being very useful in identifying the illness. Conversely, samples of conjunctival scrapings were not as useful in infection identification because only 67% of animals with neurological sigs were positive. In the second experiment, we quantified and correlate neural apoptosis and viral load in the frontal lobe, hippocampus and cerebellum by real time PCR of 21 naturally infected dogs with canine distemper. We also evaluate the relation between this factors and neurological signs. Gene expression of anti (Bcl-2) and pró-apoptotic (Bax, caspase-3, caspase-8) factors showed that canine distemper virus induces apoptosis in the hippocampus, by the extrinsic and intrinsic pathways, and in cerebellum, by an intrinsic pathway (p<0,05). Despite the higher viral load in cerebellum, there was no statistical difference in the amount of viral load among the three brain regions (p>0,05). There was also no significant correlation between gene expression of apoptotic factors and viral load in the evaluated brain regions (p>0,05), neither possible association with neurological signs too. We concluded that there is no correlation, positive or negative between virus load, apoptosis genetic expression in the brain and neurological signs in natural distemper canine virus infection in dogs