Public health awareness and seroprevalence of rabies in dogs in Limpopo National Park, and the phylogeny of rabies virus in Mozambique

Abstract

Rabies is a fatal and neglected viral disease representing one of the major public and veterinary health concerns in developing countries, particularly in Africa. The prototype causative agent (Rabies lyssavirus (RABV)) belongs to the genus Lyssavirus, family Rhabdoviridae. RABV cycles are sustained mainly by domestic dogs, responsible for most animal and human rabies cases. In Mozambique, dog-transmitted rabies has been acknowledged as a significant public health threat since 1908. This project sought to assess the level of knowledge, attitudes and practices with regard to rabies in remote areas of Limpopo National Park (LNP) in Massingir district and to understand the molecular epidemiology of the disease not only in that region, but in Mozambique in general. A cross-sectional study was conducted between 2016 and 2018 in 233 households residing in eight LNP villages and among 42 health practitioners from eight health facilities who were selected using snowballing and purposive procedures, respectively, in Massingir district. In summary, 18.9% (44/233) and 13.3% (31/233) of the households had good knowledge and practices of rabies, respectively. For health practitioners, only 16.7% (7/42) had good knowledge, whilst 33.3% (14/42) adopted adequate attitudes/practices towards the disease. In conclusion, both households and health practitioners displayed poor levels of knowledge and adopted bad attitudes and practices towards rabies. A lack of community-based education and professional retraining courses were determining factors contributing for the poor awareness of rabies. This study therefore provides an opportunity to enhance public health knowledge and reduce dog-mediated human rabies deaths. To assess the level of circulating rabies antibodies in dogs from LNP, canine sera samples were tested using a BioPro® Rabies ELISA Antibody kit. Among the 418 surveyed dogs, (89.2%; n=373) were negative for rabies antibodies (PB < 40%, 95% CI: 85.77 - 91.96) and only 6.5% (n=27; PB ≥ 70%, 95% CI: 4.4 - 9.4) had positively adequate circulating rabies antibodies levels. These findings confirm the low coverage of parenteral mass vaccination campaigns indicating high susceptibility of these dog populations to rabies virus infection. Molecular tools including real-time reverse transcription polymerase chain reaction testing and nucleotide sequencing are useful for lyssavirus identification. To enhance our understanding of rabies molecular epidemiology in Mozambique, eight rabies viruses (RABV) collected in domestic dogs (n=7) and a cat (n=1) in Maputo, Gaza, Nampula and Sofala provinces of Mozambique between 2017 and 2018 were characterized by both reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR (RT-qPCR). Five (62.5%) were positive by RT-PCR. However, lyssavirus RNA was detected in all eight (100%) samples using the most sensitive RT-qPCR. The amplicons representing partial regions of nucleoprotein and glycoprotein genes were sequenced using Sanger dideoxy chain termination. Phylogenetic trees generated from nucleotide sequences of both genes and constructed using Molecular Evolutionary Genetics Analysis (MEGA X) software, had similar topologies. The viruses clustered with other canid viruses of the Africa 1b lineage of rabies viruses originating from dogs from neighbouring South Africa, Tanzania and Zimbabwe. Further analysis demonstrated that the RABVs from Mozambique clustered with other dog rabies viruses from Zimbabwe and South Africa. It can be concluded that rabies virus circulating in Mozambique has a common progenitor, highlighting the important role of the domestic dog in rabies cycles and the transboundary nature of rabies. Rabies surveillance, laboratory diagnosis capacity and sample submission are still inadequate. The implementation of rabies control and prevention strategies that take into consideration low level of community awareness to rabies and the inadequate level of rabies antibodies in dogs in villages in and around the LNP should be considered.