Samian squirrel malaria
Simian malaria is a parasitic blood disease that affects squirrel monkeys (Saïmiri). It is caused by microscopic parasites called Plasmodium, the same types of parasites that cause malaria in humans. These parasites live and multiply inside...
What is it?
Simian malaria is a parasitic blood disease that affects squirrel monkeys (Saïmiri). It is caused by microscopic parasites called Plasmodium, the same types of parasites that cause malaria in humans.
These parasites live and multiply inside the animal's red blood cells. This disease is mainly known in saimiris living in tropical areas where mosquitoes carrying the parasite are present, or in animals that have been in contact with other infected primates.
In captivity, outside their natural environment and without exposure to mosquito vectors, the risk is very low. However, vigilance remains essential for any saïmiri who has traveled or stayed in a tropical risk zone.
Key point
This disease can quickly progress to a serious form, particularly in young animals or weakened individuals. Prompt veterinary care is essential.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The signs are often subtle at first, making detection difficult.
We generally observe marked fatigue, an animal less active than usual and which eats less.
Fever may appear, sometimes intermittently, that is to say in waves.
At a more advanced stage, the mucous membranes (gums, inside of the lips) may become pale due to the destruction of red blood cells by the parasite. Jaundice, i.e. a yellowish discoloration of the skin or eyes, may also appear.
Gradual weight loss and a dull coat are common with prolonged infection.
Some animals exhibit tremors or episodes of general weakness.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The disease is caused by parasites of the genus Plasmodium, single-celled microorganisms that infect red blood cells.
Several species of Plasmodium can affect non-human primates, with varying degrees of severity depending on the type of parasite and the health status of the animal.
The main risk factor is the presence of mosquito vectors in the animal's environment, which mainly concerns saimiris living in tropical areas or having traveled to this type of region.
A weakened immune system, young age, or a state of stress linked to conditions of captivity can worsen the course of the disease.
Contact with other species of primates carrying the parasite, particularly in zoos or primatology centers, also increases the risk.
Transmission
Transmission occurs mainly through the bite of mosquitoes of the Anopheles genus, which act as a vector, that is to say an intermediary transporting the parasite from an infected animal to a healthy animal.
The parasite is not transmitted directly from one squirrel to another by simple contact. Transmission by blood transfusion or contaminated medical equipment (needles) is theoretically possible but remains exceptional.
In rare documented cases in primates, transmission from mother to offspring during gestation has been reported.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian suspects the disease based on the symptoms and the context (exposure to mosquitoes, stay in a tropical zone, contact with other primates).
The definitive diagnosis is based on a microscopic examination of a blood smear, which allows you to see the parasite directly inside the red blood cells.
Additional tests, such as blood tests to assess the degree of anemia and the general condition of the animal, are often carried out in parallel.
Molecular biology techniques (search for parasite DNA) can be used in certain specialized laboratories to confirm the diagnosis.
Treatment
The treatment is based on specific antiparasitic molecules directed against Plasmodium, to be chosen and adapted only by a veterinarian experienced in primates.
Supportive treatment is often associated: fluids to combat dehydration, nutritional support, and sometimes blood transfusion in cases of severe anemia.
Close veterinary monitoring is essential throughout the duration of treatment.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention is primarily based on the fight against mosquitoes: mosquito nets on enclosures, repellents suitable for primates validated by a veterinarian, and elimination of areas of stagnant water conducive to mosquito breeding.
Regular veterinary checks are recommended for animals living in risk areas or returning from tropical areas.
There is no vaccine available for this disease in saimiri.
Possible complications
Severe anemia, that is to say a significant drop in the number of red blood cells, is the most common complication and can put the animal's life in danger.
Damage to internal organs, particularly the liver and spleen, may occur in the event of prolonged or untreated infection.
In severe forms, failure of several organs can appear and be life-threatening.
When to see a veterinarian
The animal seems abnormally tired or remains prostrate for several hours.
A fever or episodes of abnormal temperature are noted.
The gums or inside of the lips appear pale or yellowish.
The animal has refused to eat for more than a day.
Unexplained weight loss is observed.
Any unusual behavior after a stay in a tropical area or contact with other primates.
Transmission to humans
Certain species of Plasmodium infecting non-human primates can, in rare documented cases, be transmitted to humans, notably through the bite of the same mosquito vector having previously bitten an infected animal.
The risk remains generally low in a well-managed captivity context, but anyone working in contact with saimiris in a risk area must adopt protective measures against mosquito bites and consult a doctor in the event of an unexplained fever after such contact.
Prognosis
The prognosis depends on the speed of treatment and the species of Plasmodium involved.
Diagnosed early and treated by a specialist veterinarian, the disease can be overcome with a good recovery.
Without treatment, the progression can be severe, particularly because of anemia, and threaten the life of the animal.
Frequently asked questions
Can my saïmiri catch malaria in France or Tunisia without having traveled?
The risk is very low in the absence of competent mosquito vectors and infected animals nearby. The disease is mainly reported in tropical areas or in animals that have been in contact with primates carrying the parasite.
Is monkey malaria contagious between monkeys?
No, it is not transmitted directly from one animal to another by contact. Transmission requires a mosquito vector that bites an infected animal and then a healthy animal.
Can I give my saïmiri an antimalarial myself?
No. These medications should only be prescribed and dosed by a veterinarian, as improper use can be dangerous and ineffective against the parasite.
How do I protect my saimiri from mosquitoes?
Use suitable mosquito nets on the enclosure, eliminate nearby standing water, and ask your veterinarian for advice on safe primate repellents.
References
CDC — Centers for Disease Control and Prevention
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 23 September 2026
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