968 
ANIMAL DISEASES 
their research and who are not familiar with 
various epidemiologic factors associated with 
the transmission of these simian agents to man 
and other animals. 
Human infection and deaths have been re- 
ported for: 
H. simiae — ^this virus, more commonly known 
as B virus, produces in its original host, Macaca 
sp., a disease similar to that seen in man as a 
result of infection with herpes simplex (H. 
hominis). Transmitted to man by a monkey 
bite, although other routes are suspected, a fatal 
disease results. The few recognized survivors 
have been reduced to the level of a vegetable 
existence. Antigenically H. simiae is closely re- 
lated to H. hominis but little, if any, protection 
is offered by the presence of antibody to this 
virus even though serologic cross reactions are 
noted. A vaccine has been prepared by one com- 
mercial company but as yet it has not been 
licensed. 
Marburg virus (green monkey disease) — an 
unclassified virus considered generally to be a 
rhabdovirus because of its size and bullet shape. 
An "epidemic" due to this virus occurred in 
Germany (Marburg-Frankfurt) and Yugo- 
slavia in 1967 and thus far has not been re- 
ported again. Both countries had received Afri- 
can green monkeys from the same shipment 
out of Uganda. Animal handlers were not in- 
volved. Laboratory technicians handling monkey 
tissues and blood as well as hospital staff 
(nurses and pathologists) in contact with pa- 
tient tissues and blood were those that became 
ill. Approximately 30 cases occurred with 8 
deaths. Venereal transmission is known to have 
occurred in one instance. As indicated, this dis- 
ease has not reappeared and there is still some 
question regarding its exact epidemiology. Con- 
flict in interpreting serologic results that sug- 
gest an African simian reservoir has developed, 
with some investigators indicating that such a 
potential exists where as other groups have 
not been able to substantiate this finding."-!^ 
Additional collaborative studies concerning this 
problem are underway in several laboratories. 
In addition to these human infections, several 
of the simian viruses have produced widespread 
disease among nonhuman primate colonies. 
Among these that should be mentioned are : 
Poxviruses — three separate and distinct pox- 
viruses have been recovered from nonhuman 
primates {Macaca sp.). Of these, monkeypox 
is considered to be a natural disease of simians 
and has been reported as occurring in a variety 
of monkeys and apes^"-^^ as well as in man.^^ 
This virus is very closely related to the variola- 
vaccinia complex and nonhuman primates may 
be protected by vaccination with vaccinia.^^"^* 
The epizootiology of this disease is still suspect 
and it is conceivable that monkeypox infection 
of simians results from contact with a poxvirus 
infection of another animal. This premise is 
based upon serologic data indicating a lack of 
antibody to poxviruses in simian populations. 
As mentioned above, cases of human disease 
as a result of infection with monkeypox virus 
occurring in unvaccinated humans in Africa 
have been recently reported. 
Yaba virus was first described by Bearcroft 
and Jamieson as an outbreak of subcutaneous 
tumors occurring in rhesus monkeys in Yaba, 
Nigeria. Rhesus and cynomolgus monkeys are 
highly susceptible but African species are only 
susceptible when reared in countries outside 
Africa. This, along with the high susceptibility 
of Asian species, would suggest that Yaba virus 
is common to Africa with widespread infection 
and subsequent immunity developing.^^-^^ Hu- 
mans are susceptible to experimental or acci- 
dental infection with development of histi- 
ocytomas similar to those seen in monkeys. 
Regression of tumors occurs in 6-8 weeks. Since 
this virus is not antigenically related to vac- 
cinia-variola, vaccination with one of these vi- 
ruses is of little value. 
Yaba-like virus infection of monkeys has been 
reported from several monkey colonies. The 
original source of this virus, however, is un- 
known. Clinically this disease resembles a 
milder form of Yaba, running its course in 
about 2 weeks. The lesions are tumor-like in 
appearance, occurring on the skin. Human in- 
fection has been reported and, as in Yaba dis- 
ease, vaccination with vaccinia virus is of no 
value. 
Simian Hemorrhagic Fever virus — several 
epizootics with high mortality rates have oc- 
curred as a result of this virus in colonies of 
macaques in the U.S., England and Russia. 
