Hydrocephalus in Amazona aestiva - case report

ABSTRACT Hydrocephalus is an important neurological disorder rarely described in birds. The present report aims to describe a natural case of hydrocephalus in a blue-fronted parrot (Amazona aestiva) from a conservationist breeding (Minas Gerais, Brazil), clinically affected with neurological signs. The post-mortem lesions noted were megalencephaly, distension and thinning of the skullcap, underdeveloped brain, thickening of the meninges and the presence of a large volume of approximately 10mL of clear cerebrospinal fluid (CSF). The histopathological evaluations demonstrated discrete multifocal malacia, associated with gliosis and neuronal satellitosis in the central nervous system. The screening for viruses revealed the absence of several common etiologies, including Alphavirus (genus universal primers), avian Bornavirus, Alphaherpesvirinae (subfamily universal primers), Paramyxovirus (family universal primers), Newcastle’s disease virus (avian Orthoavulavirus 1), influenza A virus (Alphainfluenzavirus), Marek's disease virus (Mardivirus, Gallid herpesvirus 2), West Nile virus, Flavivirus (Orthoflavivirus universal primers), Apicomplexa (universal primers) and Toxoplasma gondii, all tested negative by PCR or RT-PCR. The aerobic bacteriology and mycology of the CSF did not reveal growth. The results suggest that the chronic accumulation of CSF with increased cranial pressure resulted in distension of the skull, possibly due to congenital causes of increased production, drainage or circulation.