Phylogenetic analyses of Chlamydia psittaci ompA gene sequences from captive blue-fronted Amazon parrots (Amazona aestiva) with hepatic disease in Brazil.

Chlamydia psittaci was detected in 152 (72%) blue-fronted Amazon parrots (Amazona aestiva, parrot from the Psittacidae family) out of a population of 212 that died during 2009-2011 in a wildlife rescue and rehabilitation centre in Minas Gerais, Brazil, following rescue from illegal wildlife trafficking. The macroscopic changes observed in these animals were hepatomegaly with multifocal white foci visible at the serosal surfaces of the liver, and extending into the parenchyma, and splenomegaly. The microscopic lesions observed in the liver included multifocal to coalescing miliary necrosis of hepatocytes with infiltration by heterophils, lymphocytes and plasma cells. In the spleen, loss of the normal architecture and infiltration by macrophages and plasma cells were observed. Stained tissue sections (Gimenez technique) revealed small round clusters suggestive of C. psittaci (reticulate bodies) in the cytoplasm of macrophages from the liver and spleen. Nine sequences of segments of the ompA gene, obtained from different individuals, were randomly selected for sequencing. The phylogenetic analyses showed that all strains clustered with genotype A, which is the most virulent genotype for birds. This genotype is involved in mortality of psittacines, is easily transmitted in captivity and represents a problem for successful rehabilitation. The results indicate the necessity to improve biosecurity in triage and to provide individual personal protection for professionals and caretakers.