Hamadryas herpesvirus
Hamadryas herpesvirus is a viral infection that affects hamadrya baboons, primates native to East Africa and the Arabian Peninsula.\nIt is caused by viruses of the Herpesviridae family, close to those found in other Old World monkeys.\nThis...
What is it?
Hamadryas herpesvirus is a viral infection that affects hamadrya baboons, primates native to East Africa and the Arabian Peninsula.\nIt is caused by viruses of the Herpesviridae family, close to those found in other Old World monkeys.\nThis disease is particularly feared because some of these viruses can, in rare cases, be transmitted to humans with serious consequences.\nIt affects especially animals living in groups, both in captivity and in the wild, where close contact favors the spread.
Key point
This disease presents a serious zoonotic risk: any human contact with a hamadryas suspected of carrying the virus, particularly via a bite or scratch, requires emergency medical consultation in addition to veterinary care for the animal.
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:
In hamadryas, the infection can remain silent for a long time, the virus remaining hidden in the body without causing visible signs.\nDuring the active phase, small vesicles or crusts are observed around the mouth, snout or genitals.\nThe animal may present with fever, general depression and loss of appetite.\nIn more severe forms, nervous disorders may appear: tremors, convulsions, changes in behavior or partial paralysis.\nExcessive salivation and mouth ulcers are sometimes noted, especially in young or weakened animals.
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 a herpes virus which takes up permanent residence in the nerve cells of the infected animal.\nOnce the infection has taken hold, the virus alternates between phases of sleep and phases of reactivation, often triggered by stress or a drop in immune defenses.
Animals living in dense groups, whether in captivity or in the wild, are more exposed.\nStress, environmental changes, immunity weakened by disease or age favor reactivation of the virus in carriers.\nYoung animals and socially dominated individuals may be more vulnerable.
Transmission
The virus is mainly transmitted by direct contact with infected secretions: saliva, skin lesions or genital mucous membranes.\nBites, scratches and close social contacts typical of the group life of hamadryas favor the spread between individuals.\nTransmission from mother to child can also occur during close care.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian relies on the clinical examination of skin and mucosal lesions, associated with the history of the animal and the group.\nSamples of the lesions or blood can be sent to a specialized laboratory to confirm the presence of the virus by molecular biology tests.\nA differential diagnosis with other infectious or parasitic diseases is often necessary.
Treatment
There is no treatment to permanently eliminate the virus from the body.\nThe veterinarian can prescribe specific antivirals to limit viral replication during active phases.\nSupportive care including pain and fever management, as well as local care for skin lesions, is put in place.\nIn the event of neurological damage, emergency treatment is necessary.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
There is no vaccine available for this disease in hamadryas.\nPrevention is based on good management of social groups, reduction of stress and isolation of animals with active lesions.\nRigorous hygiene of facilities and equipment limits the spread between individuals.\nFor people in contact with these animals, wearing gloves and appropriate protection is essential, particularly in the event of visible lesions in the animal.
Possible complications
Severe neurological forms can lead to lasting after-effects or even death of the animal.\nBacterial superinfections of skin lesions are possible.\nIn contaminated humans, the infection can progress to serious damage to the nervous system, potentially fatal if not treated quickly.
When to see a veterinarian
Appearance of blisters, crusts or ulcers around the mouth or genitals of the animal.\nFever associated with unusual depression.\nNeurological signs such as tremors, convulsions or sudden change in behavior.\nAny bite or direct contact of a human with a hamadryas with suspicious lesions.
Transmission to humans
Certain non-human primate herpesviruses can, in rare cases, infect humans through direct contact with the saliva or lesions of an infected animal.\nIn humans, the infection can be serious and affect the central nervous system.\nAny bite, scratch or contact with the secretions of a hamadryas must be reported immediately to a doctor, in addition to veterinary consultation for the animal.\nProfessionals working with these primates must follow appropriate measures strict protection.
Prognosis
The prognosis varies depending on the form of the disease.\nLocalized cutaneous forms generally have a favorable outcome with healing of the lesions within a few weeks.\nNeurological forms are more worrying and can be life-threatening for the animal.\nThe virus remains present in the body for life, with a risk of recurrence during periods of stress or reduced immunity.
Frequently asked questions
Is hamadryas herpesvirus dangerous for humans?
Yes, in rare cases, some primate herpesviruses can be transmitted to humans through contact with saliva or lesions and cause serious illness. Any exposure should be reported to a doctor immediately.
Can an infected hamadryas recover completely?
No, the virus remains present in the body throughout the animal's life, even after the symptoms disappear. Reactivations remain possible, especially in times of stress.
How is the virus transmitted between hamadryas?
Mainly through direct contact with saliva, skin lesions or genital secretions, during social interactions, bites or care between individuals in the group.
Is there a vaccine to protect hamadryas from this disease?
No, there is no vaccine currently available. Prevention is based on stress management, hygiene and isolation of animals with active lesions.
References
CDC — Centers for Disease Control and Prevention
WOAH — Organisation mondiale de la santé animale (ex-OIE)
AVMA — American Veterinary Medical Association
Content reviewed by the TunisieVet editorial team · Updated 23 September 2026
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