ABSTRACT
Rabies is caused by all members of the Lyssavirus genus in the family Rhabdoviridae, a group of bullet-shaped, single-stranded, negative-sense ribonucleic acid (RNA) viruses. Since the initial
discovery of the Lyssavirus genus, there have been multiple virus species added, and currently this genus consists of 12 species and
2 putative members. Classical rabies viruses, including the rabies
vaccine strains, are grouped under rabies virus (RABV), and this
group occurs almost worldwide, whereas the remaining species are
also known as rabies-related lyssaviruses. Apart from RABV, Lagos
bat virus (LBV), Mokola virus (MOKV), Duvenhage virus (DUVV),
Shimoni bat virus (SHIBV), and Ikoma virus (IKOV) have been
reported exclusively from the African continent. The fluorescent
antibody test (FAT) is considered the gold standard for lyssavirus
diagnostics, recommended by both the World Organization for
Animal Health and the World Health Organization. Other diagnostic
methods such as histological examination, immunohistochemistry,
reverse transcriptase polymerase chain reaction (RT-PCR), and
isolation of the virus in cell culture or suckling mouse brain, as
well as rapid immunodiagnostic tests have also been developed. For
most countries in Africa no epidemiological data for lyssaviruses
are known; however, an estimated 55,000 human deaths still occur
annually due to rabies and 40% of these are presumed to occur
in Africa. Lyssavirus diagnostics and surveillance in the developing
world are seriously hampered due to the lack of diagnostic facilities,
logistical support, and infrastructure. These difficulties in obtaining
a diagnostic result from field specimens have led to serious
underreporting of the disease and ultimately resulted in a lack of
commitment to control the disease. The levels of commitment for the
control of rabies in Africa are generally very low and the surveillance
for lyssaviruses inadequate, to say the least. Several reasonably
simple diagnostic methods are available to identify lyssaviruses and
to improve surveillance. These methods will be discussed in more
detail in the following sections-in the context of their utility in the
developing world.
