History and exam
Key diagnostic factors
common
presence of risk factors
Key risk factors include close contact with macaque monkeys, macaque body fluids, or tissues or objects contaminated by macaque body fluids or tissues.
fever (≥37.5°C)
Presenting symptom in most patients with B virus infection.[3]
flu-like symptoms
Majority of diagnosed cases of B virus infection report malaise, fatigue, muscle aches/pains, and listlessness, which typically occur at onset of acute disease.[3]
paraesthesias
Numbness and/or tingling at the site of infection is a presenting symptom in many patients with B virus infection, and typically occurs within hours to days post-exposure.
Numbness and/or tingling in the lower limbs may be a symptom of peripheral or central nervous system (CNS) involvement.
Symptoms indicating CNS involvement are most alarming.
hyperaesthesias
A sign of neurological involvement; may be peripheral rather than CNS involvement.
severe persistent headache
A symptom that may indicate CNS invasion.[52] Symptoms indicating CNS involvement are most alarming.
Reported in most patients with B virus infection entering the acute phase of infection.
dizziness
A symptom that may indicate CNS invasion. Symptoms indicating CNS involvement are most alarming.
Reported in most patients with B virus infection entering the acute phase of infection.
ocular pain
A symptom of CNS involvement. Symptoms indicating CNS involvement are most alarming.
Typically associated with splash injury to face and neck (specifically exposure of the eye and mucous membranes).
gait disturbances
A sign of peripheral nervous or CNS involvement. Signs indicating CNS involvement are most alarming.
Reported in most patients with B virus infection during advancing acute infection.
ataxia
May be a sign of CNS involvement.[52] Signs indicating CNS involvement are most alarming.
diplopia
A symptom of CNS involvement. Symptoms indicating CNS involvement are most alarming.
agitation
A sign of CNS involvement. Signs indicating CNS involvement are most alarming.
meningismus
A sign of CNS involvement. Signs indicating CNS involvement are most alarming.
uncommon
muscle weakness (paresis)
A sign of infection progressing to CNS involvement.[52] Signs indicating CNS involvement are most alarming.
May be the first presenting symptom in late-onset B virus infections.
persistent hiccups
A sign of CNS involvement. Signs indicating CNS involvement are most alarming.
May suggest neurological disease at the level of the diaphragm. Not frequent, but an important sign when present.
dyspnoea
A symptom of CNS involvement. Symptoms indicating CNS involvement are most alarming.
Only reported in some patients.
ascending or acute flaccid paralysis
A sign of infection progressing to CNS involvement. Signs indicating CNS involvement are most alarming.
Ascending flaccid paralysis reported in a substantial minority of patients with B virus infection.
May be the first presenting symptom in late-onset infections.
vesicular lesions
Typically localised to site of exposure.
Characteristics of lesions similar to lesions caused by herpes simplex virus infection.
Other diagnostic factors
common
nausea/vomiting
Reported in a large proportion of patients with B virus infection.
Occurs within days, weeks, or months post-exposure.
conjunctivitis
Occurs in the majority of patients who are in the midst of advancing acute infection.
Also occurred in a patient infected via a splash exposure to the eye without injury.[3]
uncommon
rash
Reported in some patients with B virus infection. May be due to non-specific inflammation at the site of infection, reaction to replication of herpes virus locally, or may be unrecognised herpetic lesions. May be pruritic.
lymphadenitis
Reported rarely in some patients.
lymphangitis
Reported rarely in some patients.
abdominal pain
Reported in some patients.
Occurs within days, weeks, or months post-exposure.
Risk factors
strong
occupational exposure
Animal handlers (e.g., veterinarians, laboratory personnel) working in facilities that house macaques have the highest degree of risk for B virus exposure, due to high rates of infection history among captive macaques, and daily or frequent close contact with potentially infected animals and to possibly infectious fluids and tissues. Infection can be transmitted through bites or scratches from an infected macaque or injuries exposed to body fluids from an infected macaque, but also through splashes without injury to exposed mucous membranes or open wounds.[4][19]
Infections have occurred in laboratories via exposure to cell lines infected with B virus. Infections have occurred after injury or following exposure to cages, sharp objects, and other objects contaminated with macaque body fluids or tissues. Aerosols were suspected as the exposure source for at least one infection.[20][21][22][23][24][25][26]
travel to countries with free-roaming macaques
Macaques roam freely in a large number of temples, parks, and other settings in southern Asia, most notably in Indonesia, Nepal, and India. Many temples and parks in Asian countries encourage visitors to pose with monkeys for photos and to bring food for the monkeys.[11][12][39] Visitors should avoid direct contact with monkeys as macaques in these settings have high rates of infection. Studies indicate that rates of B virus infection among these primate populations is similar to those of captive macaques.[2][12][39][40]
Macaques live in social hierarchies defined by aggression by dominants against subordinates, and macaque monkeys (especially females) can be aggressive towards humans, especially small children. Rhesus monkeys have been observed to swarm a tiger.[17]
keeping macaques as pets
Macaques grow more aggressive with age, but if they have never been housed with other macaques they have a lower risk of being B virus infected. However, a small study found that around 66% of pet macaques are B virus seropositive.[9] Unless a pet macaque has been tested and documented to be B virus negative, it should be assumed to be infected and intermittently shedding B virus.
weak
exposure to non-macaque species that have been housed with macaques
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