SECRETARY'S REPORT 169 



Still under observation. The euthanized individual was an 8-month- 

 old female sooty mangabey {Gercocehus fuliginosus) \ the three 

 monkeys under observation are two 10-month-old Barbary apes 

 {Macaca sylvamif^) , one male and one female, and one hybrid macaque 

 [M. pliilippinensis X M. irus). Tissues were also taken for viral iso- 

 lation attempts from two black-crested mangabeys {Gercocehus ater- 

 rimus) with histories of at least one CNS seizure. One of these 

 monkeys was apparently blind without visible defect in the eyes, and 

 both seemed normal in all other respects. 



Although no viral agents were isolated from the black-crested 

 mangabeys mentioned above, the histopathological sections of the blind 

 animal showed enough lesions in the optic nerve to account for its 

 blindness. It has not been determined what was responsible for these 

 lesions although they appear to be of long standing. No viral agent 

 has been demonstrated in the tissues from the 8-month-old sooty 

 mangabey described above. All ^dral isolation attempts included 

 culture and intracerebral mouse and hamster inoculation. 



The three remaining young macaques still mider observation have 

 been free from seizures and any other abnormal clinical signs for ap- 

 proximately 3 months. 



The virus isolation attempts were performed by Dr. Anthony Mor- 

 ris, chief of the Section on Respiratory Viruses of the Laboratory of 

 Virology and Rickettsiology, Division of Biologies Standards, Na- 

 tional Institutes of Health. 



From the past 4 years' experience with this condition, several facts 

 became apparent. First, the condition has occun'ed only in Old 

 World monlveys, the Cercopithecidae (except for one gibbon, Hylo- 

 hates sp.). It has involved the genera Macaca^ Gercocehus^ Gercofi- 

 thecus^ and Hylohates (one case), with the genus Macaca most often 

 noted. Second, there seems to be no relation to the habitat of the ani- 

 mal, some cases appearmg in a closed exhibit building, others in all- 

 season outdoor cages, and one case in a monkey that had been raised 

 in a keeper's home from the day of birth. Third, the condition is 

 first seen when the animal is usually less than a year old. Both sexes 

 have been affected but females predominate. Fourth, those animals 

 which have died usually did so after the first or second noted CNS 

 seizure. Several animals which had one or two seizures in their first 

 year have been followed until age 21^ without report of additional 

 seizures and without apparent blindness. Fifth, in none of the cases 

 has there been any diarrhea during or after the seizure, nor had there 

 been any evidence of inappetence. Some animals which had been 

 eating at the onset of the seizure began to eat again within minutes 

 after the attack, and there was no animal noted that did not eat within 

 the day. 



