S. S. KALTER 
971 
cently reviewed the status of nonhuman pri- 
mates and Australia antigen. 
Myxoviruses — the myxoviruses that are sig- 
nificant, as far as simians are concerned, appear 
to be of human origin. 
Measles (Rubeola) infections are rather com- 
mon among different species of nonhuman pri- 
mates and the virus may be encountered in 
various tissues of these animals. For example. 
Ruckle '^^ recovered an agent, MINIA, (monkey- 
intra-nuclear-inclusion agent) , from monkey tis- 
sues which is now recognized to be the same as 
measles virus. Infection of all primates with 
this virus is a result of contact with man. Newly 
captured animals do not have any evidence of 
infection and subsequently convert to seroposi- 
tive during captivity. Generally this infection is 
mild with overt disease a rare occurrence. How- 
ever, the marmoset may be exquisitely sensitive 
as infection of these animals with measles virus 
does produce a widespread and fatal infection.^* 
The full spectrum of simian susceptibility to 
this virus is not known. 
Other myxoviruses are known to infect sim- 
ians but generally produce inapparent or mild 
disease. It is highly probable that virus strain 
and dosage are important. CCA (chimpanzee 
coryza agent) was first isolated from a chim- 
panzee with respiratory illness by Morris et al.'''^ 
It was later demonstrated by Chanock et al.'^^ 
that this virus is responsible for respiratory dis- 
ease of infants (RS-respiratory syncytial) and 
is a human rather than a simian virus. Mumps 
virus was reported by Block '^^ as capable of 
producing clinical parotitis in monkeys but this 
apparently is a rare occurrence. Likewise, in- 
fluenza (at least certain strains) may produce 
mild respiratory disease in monkeys.'^^'^^ 
Herpesviruses — brief mention should be 
made of infection of nonhuman primates with 
two human herpesviruses, the Epstein-Barr vi- 
rus (EBV) recovered from human lymphomas 
occurring in Africa (Burkitt's tumor) and H. 
hominis which is one of the more prevalent of 
human viruses. 
There is no evidence of overt disease occur- 
ring in simians as a result of natural or even 
experimental infection with EBV.^^ However, 
seroepidemiological studies have demonstrated 
that a number of simian species do possess anti- 
bodies to this agent.^^-^2 Recently we have dem- 
onstrated that there is a phylogenetic suscep- 
tibility, again as indicated by the presence of 
antibody, to EBV among the monkeys and apes 
(unpublished data). This may be interpreted 
as suggesting that only ape and higher monkey 
may be used successfully for experimental stud- 
ies with this virus or perhaps may even be 
responsive to natural infection. 
Recent experimental studies with H. hominis, 
type 2 by London et al.^^ and Nahmias et al.^* 
have demonstrated that the capuchin monkey 
(Cebus apella, C. albifrons) was susceptible to 
vaginal infection with this virus. The rhesus 
(M. mulatta) and squirrel monkey (Saimiri 
sciureus) did not develop any genital lesions. 
In our laboratory the susceptibility of the capu- 
chin to H. hominis was confirmed. The baboon 
(Papio cynocephalus) was also found to be re- 
sistant but the marmoset (Saguinus oedipus 
and S. fuscicollis) was highly susceptible with 
death resulting unless small doses of virus (10- 
100 TCID50) were employed.^^ 
SUMMARY 
Some 20 years have passed since monkeys 
have been introduced into the laboratory for 
large scale biomedical experimentation other 
than for behavioral studies. The finding that 
monkeys and apes harbor numerous viruses 
apparently still comes as a surprise to many 
individuals who conceive of these animals as 
nothing more than "test tubes." The signifi- 
cance of these simian viruses has gained some 
recognition if only from the economic loss en- 
gendered by their presence in tissues intended 
for vaccine production. Thus, much loss of cul- 
ture material has resulted from contamination 
by one or another of these simian viruses. 
It is difficult to assess the true value of these 
events because there are so few data available. 
Animals, particularly primates, very rarely 
show any overt evidence of illness. Many times 
illness goes unnoticed until the animal is un- 
expectedly found dead in its cage. Criteria such 
as loss of appetite or hair changes may not oc- 
cur or are often not noticed and the animal will 
die with its cheek pouches full of food. The 
range of possible effects such events may have 
