The following is a sample of health problems associated with nonhuman
primates. It is not an exhaustive list. Some of these problems occur rarely,
while others pose a significant health risk. Given our genetic closeness,
there is always the possibility of transmission from human to nonhuman
primate or from nonhuman to human. This is just a brief account, to educate
and raise awareness of this issue - to learn more about any of these,
including symptoms and treatment, and to find references, visit the sources
at the end of these lists.
OW = Old World Primates; NW = New World Primates
transmission = common mode of transmission
Bacterial Diseases
There is little difference in susceptibility to this type of disease between
most primate species; however, macaques are more susceptible to tuberculosis
and enteric bacteria, while NW primates are more susceptible to the water-borne
agents (Pseudomonas or Klebsiella.) The bacteria that deserve the most
concern are Mycobacteriaciae (responsible for tuberculosis,) Shigella/Salmonella,
Campylobacter, and Klebsiella.
- bordetellosis - OW or NW
transmission: respiratory
- branhamella catarrhalis - "bloody nose syndrome" in cynomolgus
macaques
transmission: aerosol
- campylobacteriosis - OW or NW; asymptomatic carriers are
common; one of the leading causes of diarrhea in human beings
transmission: oral
- escherichia coli -
transmission: fecal-oral
- heliobacteriosis - OW, prevalent in rhesus stomachs
transmission:oral
- klebsiella - OW or NW; primarily opportunists affecting primates
that have a lowered resistance, for example, those with inadequate
nutrition. An infected primate poses threat to human infants or children
with a mild respiratory infections - reduced level of health can increase
liklihood of infection. Klebsiella is present in stagnant water, dirty
drinking receptacles, soil, and as flora of the alimentary tract.
transmission: respiratory - carried in nose and throat
- leprosy - Normally OW, but limited to certain species, like
mangabeys, others may be resistant
transmission: respiratory, possibly skin
- listeriosis - widespread in the environment
transmission: oral from contaminated food, transplacental
- pseudomonas spp. - P. aeruginosa and P. pseudomallei; human
mortality from P. pseudomallei is about 80%
transmission: P. aeruginosa ubiquitous is in moist environments
worldwide. P. pseudomallei is an environmental saprophyte in SE Asia
- salmonellosis/shigellosis - caused by separate organisms,
but signs, symptoms, and treatment are similar; both are frequently
present in the alimentary tract of nonhuman primates; Shigellosis
is a significant zoonotic disease that has frequently been transmitted
from non-human primates to man.
transmission: fecal-oral; humans can be carriers of shigellosis,
with no symptoms; spreads in monkey colonies via feces - carriers
are common and can constitute the majority of animals in a colony.
Stress can bring on disease.
- staphylococcus
transmission: commonly carried asymptomatically in the nose
and throat but occasionally infects breaks in the skin and invades
the bloodstream
- streptococcus (diplococcus) pneumoniae
transmission: respiratory
- tetanus - OW or NW
transmission: soil organism and an obligate anaerobe that contaminates
wounds and causes postpartum infections.
- tuberculosis - OW or NW, NW more resistant than OW; caused
by mycobacteria; recognized as a common disease of captive primates
for many years; not a disease of wild monkeys - caught from humans;
in nonhuman primates the signs of TB may be hard to see - only slight
behavioral changes noticed, followed by anorexia and lethargy. Often
animals die suddenly while appearing to be in good condition.
transmission: respiratory, oral
- yersiniosis - OW or NW
transmission:
wild birds and rodents are reservoir hosts - ingestion of feed
contaminated by feces of infected vermin
Fungal Diseases
Several reports have been made on systemic and superficial mycoses in
primates. Fortunately, these are isolated cases; however, there is a potential
danger to human beings. The primary pathogens are Dermatophilus congolensis
(streptothricosis,) Candida albicans, and Trichophyton mentagrophytes
(ringworm.)
- blastomycosis - OW or NW
transmission: inhalation
- candidiasis - OW or NW
transmission: ubiquitous organism - opportunistic infection
of immunocompromised, usually a secondary disorder
- coccidioidomycosis - OW or NW; limited to arid regions of
North & South America
transmission: inhalation of spores
- cryptococcosis - OW or NW
transmission: inhalation
- histoplasmosis - OW
transmission: inhalation of spores of H capsulatum from soil
rich in bird or bat excreta. H. duboisii may be spread by dermal contact
and may have a long incubation period.
- pneumocystis - OW or NW
transmission: aerosol
- ringworm - OW or NW
- streptothricosis -
OW or NW, natural disease has been reported in Aotus and Lagothrix, and
experimental infection was in rhesus, cynomolgus, and squirrel monkeys
Parasites
In the wild, many primates scavenge about villages and share not only
food but also the parasites of the human inhabitants. Danger from imported
animals, therefore, is usually during the first few months after the animal's
arrival in the country. If the parasites are effectively eliminated during
the initial quarantine adaptation period, the danger of transmission can
be eliminated. The most serious danger that arthropods pose is their role
as an intermediate biological host for parasitic diseases and as a mechanical
vector for infectious organisms. Parasites that need an intermediate host
are self-limiting but those having a direct cycle become a continual problem.
These include protozoa, nematodes, tapeworms, and arthropods. Possible
human infection from primate carriers is a constant threat.
- acanthocephala - thorny-headed worms - NW
transmission: ingestion of intermediate host (cockroach, beetle)
- anatrichosoma - OW
transmission: unknown
- athesmia - common in NW
transmission: mollusk is intermediate host
- cestodes - (tapeworms) - OW or NW; only one (Hymenolepsis
nana) of the variety of cestodes is considered a threat to humans
transmission: ingestion of eggs or infected intermediate host
- cutaneous mites - OW or NW
transmission: contact
- filarids - NW or OW, most common in NW
transmission: blood sucking insects
- lice - OW or NW
- lungworms - most common in NW
transmission: larvae passed in feces
- nochtia - OW (primarily Asian macaques)
transmission: oral
- oesophagostomum - nodular worms - OW
transmission: oral
- pentastomes - OW or NW
transmission: oral
- physaloptera
transmission: ingestion of intermediate host (cockroach)
- respiratory mites - normally OW
transmission: unknown, close contact required
- schistosoma - OW or NW
transmission: snail is intermediate host
- strongyloidiasis - (nematodes) - NW or OW, common in many
species of nonhuman primate and, because of its direct life cycle,
can be infectious for humans. There are three species
transmission: oral, skin penetration
- trichuris - whipworms - OW or NW
transmission: oral
Protozoan Parasites
Many protozoa require arthropod vectors; with vector control, they do
not cause a significant problem to man outside the environmental range
of the arthropod. Giardia and Entamoeba histolytica are the two primary
pathogens not requiring an arthropod vector. Although plasmodia cause
malaria, a disease of major importance, they are usually specific for
each primate except in experimental situations and are rarely transmitted
between nonhuman primates and humans in North America.
- amoeba - OW or NW - amebiasis is a severe disease of human
and nonhuman primate
transmission: oral
- balantidium - OW or NW; distributed worldwide, common in
swine. Humans, great apes, & several monkey species may carry it.
transmission: oral - ingestion of cysts or trophozoites from
infected animal or human feces. Contaminated water or food.
- cryptosporidiosis - uncommon
transmission: fecal-oral
- encephalitozoonosis - NW
transmission: oral, transplacental; organisms shed in urine
- giardiasis - asymptomatic carriers are common; dogs and NHP's
represent the greatest public health risk. Most common intestinal
parasite of people in the U.S., becoming a frequent cause of recurrent
diarrhea in man and nonhuman primate
transmission: fecal-oral
- hepatocystis - OW
transmission: midge
- malaria - OW or NW
transmission: mosquito
- sarcocystis - infects many species of wild-caught monkeys
transmission: fecal-oral
- toxoplasmosis - NW more susceptible than OW. Usually asymptomatic
in OW.
transmission: ingestion of food contaminated by cat feces containing
oocysts or ingestion of raw meat containing cysts (example: rodents);
rare but usually fatal
- trichomoniasis - OW or NW
transmission: fecal-oral
- trypanosomiasis - OW or NW; trypanosoma is commonly found
in the blood of South American primates, but the only one known to
be pathogenic is T. cruzi. Monkeys could be reservoirs for human infection.
T. cruzi is an important cause of human disease (American trypanosomiasis)
transmission: insect vector
Viral Diseases
These are probably the most dangerous diseases, because they are so difficult
to diagnose and treat. A virus may be latent in one species of primate,
with little or no symptoms, yet be fatal in another species of primate,
including humans.
- adenovirus - (numerous) - normally OW
- benign epidermal monkey pox - (tanapox, OrTeCa pox) - unrelated
to smallpox - OW, infects macaques and humans - rare
- callitrichid hepatitis - NW, marmosets and tamarins
transmission: rodents - endemic in mice worldwide. May be spread
by feeding pinkies.
- cytomegalovirus - normally OW, widespread latent infections
in macaques
transmission: horizontal (shed in urine), transplacental, highly
species-specific
- encephalomyocarditis virus - OW or NW
transmission: oral, perhaps other - probable rodent reservoir
- Epstein-Barr virus
transmission: contact
- focal epithelial hyperplasia of chimpanzees
transmission: close contact
- hepatitis a virus - NW or OW; nonhuman primates usually do
not show symptoms but can be carriers
transmission: fecal-oral
- hepatitis b virus - OW
transmission: infected blood, saliva, semen. Parenteral inoculation
or intimate contact required.
- hepatitis c virus - only chimps and humans
- herpesvirus ateles - NW, spider monkey is natural host
- herpes b - NW or OW, especially Asian monkeys, particularly
macaques; monkeys are probably infected for life and a high proportion
(perhaps 100%) of adults in infected colonies harbor the virus; the
reliability of negative test results has not been ascertained - it
is not certain that infected monkeys always have diagnostic titers.
Infected monkeys can appear normal, showing no symptoms. The virus
remains latent and may reactivate spontaneously or in times of stress
resulting in virus shedding
Since there is a high percentage of infection in monkeys yet relatively
few human cases, risk of acquiring infection appears to be low. Through
1987, 22 human cases were reported. A few other cases are attributed
to B virus infection, but lack adequate documentation. Twenty of the
22 human patients developed encephalitis. Fifteen of these died. Monkeys
may shed the virus infrequently. It may also be possible that some
humans are asymptomatic carriers.
transmission: bites, scratches, venereal, aerosol
- herpesvirus saimiri - (Cebid herpesvirus 2) - usually NW,
squirrel monkey is natural host
transmission: oral
- herpes simplex virus - OW or NW
transmission: latent or active infection in many humans, which
are the natural reservoir. Human to monkey and monkey to monkey transmission
from active lesions.
- herpesvirus tamarinus - (Cebid herpesvirus 1) - NW, squirrel
monkey is natural host (usually will show no symptoms); severe disease
occurs in marmosets and owl monkeys
transmission: contact, fomites, aerosol
- Marburg virus - OW or NW; ; similar to ebola virus; first
recognized in 1967 - lab workers in Germany and Yugoslavia working
with tissue cultures from African green monkeys (vervets) from Uganda
- seven out of the thirty affected died
transmission: aerosol, handling infected tissue, saliva, urine
- measles - NW or OW, most frequently reported viral disease
of nonhuman primates; NW are more resistant than old world monkeys
but exhibit high mortality when infected
transmission: Virus is excreted from the mucous membranes of
the eye and pharynx and later from the respiratory and urinary tracts.
Highly contagious. It can spread from human to monkey, human to human,
and monkey to human.
- molluscum contagiosum - OW, humans and chimps - poxvirus
unrelated to smallpox
- monkeypox - OW or NW - most frequent pox virus, related to
smallpox and vaccinia; Occurs sporadically, not epidemically
transmission: Zoonotic disease of monkeys and humans in tropical
rain forests of western and central Africa. Old and New World monkeys
and apes also susceptible. Animal reservoir unknown, but possibly
squirrels and probably not monkeys.
- papillomavirus
- rabies - NW or OW; 16 cases have been confirmed in nonhuman
primates, including chimpanzees, cebus, cynos, and squirrel monkeys.
All source countries of NHP's have endemic rabies. The vaccination
of wild animal pets for rabies is discouraged by health authorities
- modified live vaccines for dogs and cats can cause rabies in the
nonhuman primate, can only use killed vaccines, the efficacy of which
is not known.
transmission: virus laden saliva via bite, scratch, or abrasion.
Rabid animals may shed virus in saliva 1-14 days before showing signs
- simian agent (SA8) - OW, especially Papio sp. and vervets
transmission: venereal
- simian ebola-like filovirus - OW; fatal in some monkeys,
humans can be infected but do not get ill
transmission: aerosol
- simian hemorrhagic fever virus - OW, primarily patas monkeys
transmission: endemic in some wild patas hosts remain persistently
viremic, but asymptomatic for life. Animals may be viremic without
antibody. Transmission from patas to macaques appears to require parenteral
exposure to blood or body fluids. The virus spreads much more readily
among macaques by contact or aerosol. Nearly always fatal in macaques.
- simian varicella virus - OW - group of closely-related herpesviruses
transmission: respiratory - latency is common and the origin
of some outbreaks is unexplained
- SV40 - OW, primarily macaques
transmission: respiratory, virus shed in urine
- yaba pox - OW, natural infections have occurred in rhesus
and baboons; not presently understood; may be a natural indigenous
infection of wild African primates. Humans are also susceptible
transmission: obscure, but experimentally can be done by aerosol,
direct inoculation; mosquitoes have also been implicated
- yellow fever - NW, especially Alouatta spp. - disease of
Central and South America and Africa, OW also suspectible
transmission: mosquitoes in urban areas, in the
wild many mammals are natural hosts
Primate Retroviruses
Family: Retroviridae
- Subfamily: Lentivirinae (immunodeficiency viruses) - OW
- Subfamily: Oncovirinae - OW or NW - usually no disease
in natural host species but may cause natural or experimental disease
in other species
- Subfamily: Spumavirinae - (foamy viruses) - mainly OW
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