​​​​​​​Recent Research – July 2017

A selection of recent articles relevant to GARC’s mission

 

Prioritising rabies control

One Health contributions towards more effective and equitable approaches to health in low- and middle-income countries. Emerging zoonoses with pandemic potential are a stated priority for the global health security agenda. However, endemic zoonoses also have a major societal impact in low-resource settings, causing disease in people and lowering livestock productivity. Strengthening capacity for One Health interventions to control endemic zoonoses has the potential to align the needs of disadvantaged communities with the concerns of the broader global community, providing a pragmatic and equitable approach to meeting the global goals for sustainable development and supporting the global health security agenda.

Sri Lanka takes action towards a target of zero rabies death by 2020. Political will and leadership have been the main drivers for success of the Sri Lankan effort to reduce the burden of disease attributable to rabies. Post-exposure prophylaxis, provided free at government health facilities and dog vaccination have been enacted but to reach elimination in Sri Lanka by 2020, more will need to be done. Sri Lanka is the first country in the World Health Organization South-East Asia Region to develop a national strategy for elimination of dog-mediated rabies and is a key country in sharing knowledge, expertise and capacity-building in the region.

The Middle East and Eastern Europe rabies Expert Bureau (MEEREB) third meeting: Lyon-France (7-8 April, 2015). MEEREB members met in 2015 in France to review the current rabies situation within the network and discuss a One Health approach against rabies. Dogs were the main vector of transmission in all MEEREB countries except for Croatia and Serbia where foxes represented the primary source. Human cases still occur in North Africa and all Middle East and Eurasian countries while no cases of human rabies were reported in Croatia, Serbia and Romania. The countries called for elimination of dog-transmitted rabies through vaccine and rabies immunoglobulin stockpiles and implementation of a One Health approach to achieve rabies's eradication.

 

Dog Population Management

Scoping review of indicators and methods of measurement used to evaluate the impact of dog population management interventions. This scoping review collates 26 studies that have assessed the impacts of dog population management interventions. By describing the indicators used to assess the few studies conducted so far and barriers to impact assessment, this review aims to support and direct future impact assessment.
 

Dog vaccination

Rabies vaccine is associated with decreased all-cause mortality in dogs. Data from 2012-2015 from an observational study of free-roaming dogs in a low-income community in South Africa revealed that rabies vaccination reduced the risk of death from any cause by 56% in dogs aged 0-3 months, by 44% in dogs aged 4-11 months and by 16% in dogs aged 12 months and older. It is hypothesized that there is a protective effect of rabies vaccine against diseases other than rabies. Owned domestic dogs in high mortality settings provide a useful animal model to better understand any such non-specific protective effect.

Sero-prevalence of virus neutralizing antibodies for rabies in different groups of dogs following vaccination. Dogs in Sri Lanka were vaccinated with a monovalent inactivated vaccine intramuscularly and serum antibody titres on days 0, 30, 180 and 360 were checked. 40.42% of dogs without owners and 57.14% of previously unvaccinated juvenile dogs with owners did not produce protective levels of antibody by day 360. Previously vaccinated animals had higher antibody responses, but whilst unvaccinated animals had a satisfactory antibody titre by day 180, these fell by day 360.

 

Wildlife Rabies

The phylogeography of Myotis bat-associated rabies viruses across Canada. As rabies in carnivores is increasingly controlled throughout much of the Americas, bats are emerging as a significant source of rabies virus infection of humans and domestic animals. This study used Myotis bats collected over 25 years and partial genome sequencing and host genetic barcoding was used to identify several rabies variants associated with Myotis species, with different geographic spreads. The findings demonstrate that rabies virus has emerged in the Myotis genus independently on multiple occasions and highlights the potential for emergence of new viral-host associations within this genus.

Oral vaccination of wildlife against rabies: Differences among host species in vaccine uptake efficiency. Differences in the oral vaccine titers needed to induce a protective immune response against rabies in different reservoir species have been noted, but the mechanisms remain unclear. The vaccine virus strain, SPBN GASGAS, was investigated in red fox (readily vaccinated) and a species refractory to this route of administration (striped skunk). The absence of virus infected cells in palatine tonsils of skunks suggests a less efficient uptake of or infection by vaccine virus which may lead to a reduced response to oral vaccination.

 

Genetics

Using viral gene sequences to compare and explain the heterogeneous spatial dynamics of virus epidemics. Phylogeographic reconstructions of viral lineage movement are used to study of the spatial dynamics of rabies virus epidemics in different hosts and habitats. The study found a higher diffusivity of RABV in domestic dogs compared to RABV in other mammals, indicating that factors relating to human geography play a significant role in RABV dispersion in domestic dog populations. More generally, our results suggest that human-related factors are important worldwide in explaining RABV dispersion in terrestrial host species.

First Complete Genomic Sequence of a Rabies Virus from the Republic of Tajikistan Obtained Directly from a Flinders Technology Associates Card. A brain homogenate derived from a rabid dog in the district of Tojikobod, Republic of Tajikistan, was applied to a Flinders Technology Associates (FTA) card. A full-genome sequence of rabies virus (RABV) was generated from the FTA card directly without extraction, demonstrating the utility of these cards for readily obtaining genetic data.