Study recommends intervention in dog populations for preventing rabies in Asia
Rabies is a preventable viral disease that occurs in over 150 countries. More than 59 000 people die of rabies every year. Asia and Africa account for over 95 % of human rabies cases, according to the World Health Organization. In up to 99 % of cases, domestic dogs are responsible for rabies virus (RABV) transmission to humans, so it’s crucial to understand its spread. Scientists partially supported by three EU-funded projects – ReservoirDOCs, PATHPHYLODYN and VIROGENESIS – have reconstructed its recent diffusion history in domestic dogs in China’s Yunnan Province, where there is a re-emergence of rabies that started in 1999. They have used 17 years of genomic and epidemiological data and combined phylogeographic approaches and mathematical modelling to estimate RABV transmission rate between dogs and from dogs to humans. Their findings were published in the journal ‘PLOS Pathogens’. Phylogeography involves the principles and processes governing the geographic distributions of genealogical lineages. Prevention and control The researchers have noted that the absence of timely and accurate data hinders rabies control in developing countries. They have also emphasised that the number of human deaths as a result of RABV infections is underestimated. “These uncertainties inevitably hamper improvements in disease control strategies and the evaluation of control measures.” They concluded: “Our results indicate that interventions in the dog population would be effective in reducing transmission to humans, in particular because they have the potential to subvert the self-sustaining capacity of epidemics in dogs.” The researchers added: “A better understanding of RABV spread in terms of spatial and temporal dynamics is necessary to help inform the prevention and control of human rabies in the vast rural areas of China.” The ReservoirDOCs (The evolutionary dynamics of pathogen emergence and establishment: from Reservoir Detection to Outbreak Control) project that provided funding for the research was set up to investigate how key viral pathogens show up and are transmitted. As stated on CORDIS, the project team “will scrutinise the reservoir dynamics of HCV [Hepatitis C virus] by sequencing complete hepacivirus genomes from infected samples emerging from a large-scale screening of African rodents, and analyze the cross-species transmission history using novel evolutionary methods that accommodate spatial and temporal variability in selective pressures.” In addition, the ongoing project will look at the early establishment of HIV-1 and also use West Africa’s recent Ebola epidemic “as a model to develop high-performance statistical approaches for extracting practical and timely epidemiological information from virus genome sequences during epidemics as they unfold.” Another project that supported the research, VIROGENESIS (Virus discovery and epidemic tracing from high throughput metagenomic sequencing), developed bioinformatics tools for virus diagnostics using next-generation sequencing. Ending in mid-2018, it created algorithms and software applications to follow epidemic outbreaks in real time. The issue of genetic sequences was also the focus of the ongoing PATHPHYLODYN (Pathogen Phylodynamics: Unifying Evolution, Infection and Immunity) project that contributed to the same research paper’s funding. It “aims to develop and apply new mathematical, computational and statistical methods in order to analyse the vast and increasing amount of genetic data from infectious diseases,” as stated on CORDIS. The research covers human viruses, including HIV-1 and influenza. It also examines “how immune responses and virus populations respond and adapt in response to each other.” For more information, please see: ReservoirDOCs web page VIROGENESIS project website PATHPHYLODYN project on CORDIS
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