Abstract:
Rabies is considered a neglected disease among many developing Asian and African
countries, including Mozambique, where its re-emergence is often attributed to low dog parenteral
vaccination coverage. The objectives of this study were two-fold: (1) to assess the level of antibodies
against rabies virus in dogs (n = 418) in Limpopo National Park (LNP), and (2) to genetically
characterise selected rabies viruses from brain tissue samples collected in 2017 and 2018. To meet
the first objective, we used the BioProTM Rabies blocking ELISA antibody kit, and the results were
expressed as the percentage of blocking (%PB). Dog sera with PB ≥ 40% were considered positive
for antibodies to rabies virus, whereas sera with PB < 40% were negative. Just under ninety percent
(89.2%; n = 373) of dogs were seronegative, and the rest (10.8%; n = 45) had detectable levels of rabies
virus-specific antibodies. All eight brain tissue samples were positive for rabies virus antigen using a
direct fluorescent antibody test and amplified in a quantitative real-time PCR, but only five (n = 4
from dogs and n = 1 from a cat) were amplified in a conventional reverse-transcription PCR targeting
partial regions of the nucleoprotein (N) and the glycoprotein (G) genes. All samples were successfully
sequenced. Phylogenetically, the rabies viruses were all of dog origin and were very closely related to
each other (Africa 1b rabies virus lineage). Furthermore, the sequences had a common progenitor
with other rabies viruses from southern Africa, confirming the transboundary nature of rabies and the
pivotal role of dogs in maintaining rabies cycles. The study demonstrates the principal application
of the BioProTM rabies ELISA antibody for the detection of anti-lyssavirus-specific antibodies in the
serum samples of dogs, and most importantly, it highlights the low levels of antibodies against rabies
virus in this dog population.
