Мокола вирусы: Африкалық қызыл ықшамның туысы және қауіптері

Species of virus

Mokola lyssavirus, commonly called Mokola virus (MOKV), is an RNA virus related to rabies virus that has been sporadically isolated from mammals across sub Saharan Africa. The majority of isolates have come from domestic cats exhibiting symptoms characteristically associated to rabies virus infection. As of 2021, there have been two confirmed cases of Mokola virus infection in humans, of which one was fatal. The rabies vaccine does not confer cross protective immunity to Mokola virus, and no other known treatment for MOKV exists.

Mokola virus (MOKV) is a member of the genus Lyssavirus, which belongs to the family Rhabdoviridae. MOKV is one of four lyssaviruses found in Africa. The other three viruses are the classic rabies virus, Duvenhage virus and Lagos bat virus. There have been two recorded cases of human infection with MOKV, with both instances occurring in Nigeria. Both cases involved young Nigerian females. The first patient, who had been suffering from a fever and convulsions, recovered fully from infection. The genome encodes five proteins: matrix protein M; transmembrane glycoprotein G; nucleoprotein N; phosphoprotein P; and the RNA dependent RNA polymerase L.

Symptoms provoked by MOKV infection are similar to the symptoms associated with rabies virus infection, such as fever and headache. Ultimately, both MOKV and rabies virus infection can lead to death by encephalitis. The similarity between the symptoms associated with MOKV and rabies virus may be the reason why there are so few case records of MOKV infection, as MOKV infection might be falsely diagnosed as rabies virus infection. There is one significant difference between the symptoms observed in domestic cats infected with MOKV and those with rabies virus. MOKV infected domestic cats do not demonstrate the unprovoked aggressive behaviour typically associated with rabies virus infected mammals.

At present, there is no medical or veterinary vaccine that protects against MOKV infection. It has long been established that, in spite of the relatedness between MOKV and rabies virus, immunisation with the rabies vaccine does not confer protection from MOKV infection. Isolation of MOKV from a number of domestic cats vaccinated with the rabies vaccine has demonstrated this. In order to neutralize rabies virus, the rabies vaccine targets the transmembrane glycoprotein G on the viral envelope. Variation in the amino acid sequences of the antigenic domain III within protein G between rabies virus and MOKV has rendered the rabies vaccine ineffective against MOKV infection.