Clinicopathologic study of six cases of meningitis and meningoencephalitis in chimpanzees (Pan troglodytes)

Three fatal cases of purulent meningitis and one fatal case of thromboembolic necrotizing meningoencephalitis occurred in chimpanzees from the Primate Center TNO, The Netherlands. In addition, two apes had clinical signs of meningitis and were successfully treated. The severity of the residual hemiparesis and dysphagia in one of these two apes was such that it was killed for humane reasons. The histopathological diagnosis was chronic active meningoencephalitis. Streptococcus pneumoniae was isolated from five apes and Klebsiella pneumoniae from one. In the majority of cases, the primary site of infection was the upper respiratory tract. After reducing the population density, initiating a vaccination program using a commercially available human polyvalent pneumococcal vaccine, and changing the cleaning procedure of the animal facilities, no other cases of meningitis or meningoencephalitis have occurred in the chimpanzee colony in the ensuing 3.5 years.

Systemic pathology of chimpanzees

Spontaneous lesions in chimpanzees have been described according to the organ system involved. These lesions have been reported in the literature or noted in chimpanzees at the 6571st Aeromedical Research Laboratory (ARL), Holloman AFB, N. Mex., over a 15-year period. some of the lesions seen at the ARL were the result of overt clinical disease, while others represent incidental findings, the significance and genesis of which were often obscure. Conditions involving the gastrointestinal tract, especially parasitic diseases, have been and continue to be of the highest frequency, with disorders involving the cardiovascular system next. Infectious diseases have been infrequent, especially in the stabilized colony, and neoplastic conditions have not been seen.