Mokola lyssavirus (MOKV) is a negative‑sense RNA virus in the genus Lyssavirus. It was first isolated from a shrew in Nigeria in 1968 and is one of the few lyssaviruses not associated with bats. MOKV forms part of phylogroup II and is genetically distinct from classical rabies virus.
Ecology, hosts and clinical features
Since its discovery, fewer than 30 Mokola virus cases have been documented across sub‑Saharan Africa. The virus has been isolated from shrews, domestic cats, dogs and a rodent, but its natural reservoir remains unknown. Unlike most lyssaviruses, MOKV has never been detected in bats. Two human infections have been reported, both in Nigerian children; one patient survived with no neurological sequelae, while the other developed fatal encephalitis. Clinical signs in animals resemble rabies, with behavioural changes, hypersalivation and progressive paralysis. Current rabies vaccines do not confer reliable protection against MOKV infection, and there are no specific vaccines or treatments for this virus. Laboratory confirmation is achieved by virus isolation or reverse‑transcription PCR from brain tissue, and antigenic typing distinguishes MOKV from rabies virus. Because surveillance is limited, the true prevalence and host range of MOKV are uncertain.
Documented cases and public health implications
The majority of Mokola virus isolates have come from domestic cats exhibiting rabies‑like illness in South Africa and Nigeria. These cases often occur in areas where rabies vaccination coverage in cats is low, suggesting spill‑over from an unidentified reservoir. Reports from the 1990s described cats that developed hind‑limb paralysis, excessive salivation and aggression before death. In 1972 a Nigerian child developed progressive paralysis after being scratched by a dog and recovered with supportive care, while another child bitten by a cat died of encephalitis. By 2013 only 18 confirmed MOKV isolations existed, highlighting its rarity. Because rabies vaccines do not protect cats and dogs against MOKV, veterinary authorities stress the importance of diagnosing suspect cases and enhancing surveillance. People exposed to animals suspected of carrying MOKV should receive post‑exposure prophylaxis following rabies guidelines until laboratory tests are completed.
Mokola lyssavirus is a terrestrial African lyssavirus of unknown ecology. Its rare occurrence and lack of vaccine make surveillance and prompt laboratory diagnosis essential to prevent overlooked cases. Continued research into its reservoir and cross‑protection is needed.
Related Terms: Rabies Lyssavirus, Lagos Bat Lyssavirus, Duvenhage Lyssavirus, Rotavirus H, Rotavirus B