962 
ANIMAL DISEASES 
16 golden hamsters, and 50 cattle. A herpes- 
virus was obtained from the kidney cultures of 
two of the ten horses studied. These results 
indicate that certain monkeys held in captivity 
harbor a greater number of viruses than most 
laboratory or domestic animals. 
Comparison of Virus Types Recovered from 
Different Monkey Species 
The virus types recovered from different 
monkey species varied from time to time and 
from laboratory to laboratory. Table II shows 
a comparison of the different types of viruses 
isolated from the two monkey species that are 
listed in Table I, together with the percentage 
of monkeys infected with each virus type. In 
both the rhesus and green monkeys, members 
of the foamy virus group were the most fre- 
quent isolates, being 31% and 20%, respec- 
tively. The incidence of measles and SV5 isola- 
tions was low in both groups. Rhesus tissues 
were the only source of SV40, and cytomegalo- 
virus was found only in the green monkeys of 
the samples examined during the study 
period.^'^'^^ 
Circulation of Simian Viruses in Monkeys 
During Captivity 
In our earlier studies, when green and 
rhesus monkeys were quarantined for a period 
of time, a lower incidence of SV5 isolation from 
their kidneys was obtained than from monkeys 
that came directly from the fiield.^ On the other 
hand, the green monkeys showed a higher per- 
Table II. — Comparison of Virus Types Isolated from 
Kidney Cell Cultures of Green Monkeys and Rhesus 
Monkeys 
August 1969— June 1971 
Species of Monkey 
Rhesus 
Green 
Total No. Studied 
124 
108 
virus type {%) 
Foamy 
31 
20 
Measles - 
- 2 
1 
SV5 
1 
SV40 .... 
17 
0 
Cytomegalovirus 
..- _ 0 
8 
Mixed Infection . 
— 1* 
0 
* Doubly infected ■with SV40 and Foamy virus type 1. 
centage of SV40 infection the longer they were 
kept in captivity.^^-^o 
The sources of virus infection in monkeys 
are often obscure. Some of these agents, 
such as, SV40, are undoubtedly viruses of 
rhesus monkeys, and green monkeys acquired 
SV40 infection only after contact with the 
former (Figure la). A similar situation has 
been noted with foamy virus type 1 infection. 
Of a total of 184 rhesus and 64 green monkeys 
examined, from January 1967 to February 
1969, foamy virus type 1 was isolated in cell 
cultures prepared from 42 rhesus monkeys, but 
none was isolated from the green monkeys.^'^ 
However, a 4% seroconversion to foamy virus 
type 1 was found in green monkeys which were 
housed in close proximity to the rhesus mon- 
keys for 30 days or longer (Mgure lb). In con- 
trast, studies on cytomegalovirus infections in 
captive monkeys showed that the green mon- 
keys were highly susceptible to this virus, both 
by virus isolation and serologic tests. Of 108 
DNA VIRUSES RNA VIRUSES 
c. d. 
Figure 1. — During captivity, when different monkey 
species were housed together or close to each other, 
the following observations on the spread of virus in- 
fection have been made: 
Green monkeys appear to acquire SV40 (a) and 
foamy virus type 1 (b) from infected rhesus monkeys, 
but transmit cytomegalovirus (c) to the latter; both 
monkey species appear to acquire SV5 infection from 
man (d). 
