Mokola virus infection : description of recent South African cases and a review of the virus epidemiology : case report

Abstract

Five cases of Mokola virus, a lyssavirus related to rabies, are described. The cases occurred in cats from the East London, Pinetown and Pietermaritzburg areas of South Africa from February 1996 to February 1998. Each of the cats was suspected of being rabid and their brains were submitted for laboratory confirmation. Four of the cases were positive, but with atypical fluorescence, and 1 was negative. Mokola virus infection was identified by anti-lyssavirus nucleocapsid monoclonal antibody typing. As in rabies cases, the predominant clinical signs were of unusual behaviour. Aggression was present, but only during handling. Four of the 5 cats had been vaccinated for rabies, which is consistent with other studies that show that rabies vaccination does not appear to protect against Mokola virus. Since Mokola may be confused with rabies, the incidence of Mokola virus may be more common in Africa than is currently reported. As human infections may be fatal, the emergence of this virus is a potential threat to public health

Diversity and Epidemiology of Mokola Virus

“…Twenty five years later, in 1995, MOKV was isolated from a domestic cat in South Africa, this time from Mdantsane in the Eastern Cape Province (EC) [17]. Two more isolations followed in 1996, one each in KZN and EC and both from domestic cats of which one was vaccinated against rabies [18], [19]. In 1997 and 1998 three more isolations were made from rabies-vaccinated cats in KZN [18], [19].…”

Report of isolations of unusual lyssaviruses (rabies and Mokola virus) identified retrospectively from Zimbabwe : short communication

“…Most other isolates in southern Africa, including 1 from Ethiopia, have been found in domestic cats 6,7,13,20 indicating that they are a major indicator species for the virus. However, the epidemiology of Mokola virus infection is poorly understood: the maintenance host is not known, but obviously transmits the virus to domestic cats more readily than to other commonly-tested species.…”

“…Mokola virus infection is a potentially serious zoonotic disease. It may cause fatal disease in humans 4 and current rabies vaccines do not appear to protect against it 1,5,20 . Infected animals, particularly cats, present signs that may be confused with rabies and other neurological conditions.…”

“…Mokola virus has only been detected in Africa and appears to occur throughout the continent, as it has been isolated from West Africa, Central Africa, Ethiopia, Zimbabwe and South Africa. Mokola virus has been identified by surveys or in those areas where methods appropriate to identifying genotypes other than classical rabies virus were employed 20 . Lyssaviruses cause clinical disease similar to that caused by classical rabies virus.…”

“…Most isolates have been made from domestic cats, although isolates have also been made from shrews (Crocidura sp. ), a rodent Lophuromys sikapusi, a domestic dog and human beings 3,4,6,7,10,[12][13][14]17,18,20 . Mokola virus has only been detected in Africa and appears to occur throughout the continent, as it has been isolated from West Africa, Central Africa, Ethiopia, Zimbabwe and South Africa.…”