Oral Rabies Vaccination (ORV) of dogs successfully conducted in Zambezi region of Namibia

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This is a map of Zambezi region spotlighting human settlement locations divided into different vaccination zones (top) and bottom map, depicts the distribution of individually vaccinated dogs (points) during the ORV campaign.

Dog-mediated rabies poses a significant threat to public health in the Northern Communal Areas (NCAs) of Namibia, which comprises of eight regions: Oshana, Oshikoto, Omusati, Ohangwena, Kunene, Kavango East, Kavango West, and Zambezi. Under the “One Health” concept, the Namibian government adopted a National Rabies Control Strategy in 2015, aiming to contribute to the global goal of ending dog-mediated human rabies deaths by 2030. A key component of this strategy was the implementation of a dog rabies elimination programme in the NCAs. The area of implementation (NCAs) covers approximately 263,376 km² and 75 constituencies, with around 1.7 million inhabitants and an estimated 272,000 dogs.

 

After a pilot phase in the Oshana region in 2016, the mass dog vaccinations (MDV) were extended to all the northern communal areas comprising the regions of Oshikoto, Omusati, Ohangwena, Kunene, Kavango East, Kavango West and Zambezi, with the aim of establishing well-managed vaccination campaigns on an annual basis and thus high vaccination coverage in the dog populations.

The MDV approach is a cornerstone in the control and eventual elimination of the disease. However, vaccinating hard to reach, often free-roaming dogs is a challenge and represents one of the obstacles to achieving herd immunity necessary to stop the spread of the virus. Although more than 90% of the owned dogs in the NCA are free roaming but are accessible for vaccination, some are difficult (aggressive) for owners to handle and present at vaccination points.

One new tool is application of oral rabies vaccination (ORV), a method that has been successfully used in Europe and North America to control wildlife mediated rabies, and is promoted by WOAH, WHO and FAO. Along this line, a guideline and recommendations for the field application of ORV and its integration into dogs rabies control programmes is published by FAO, WHO and WOAH in 2023.

Immunogenicity of ORV in Namibian dogs study involving the University of Namibia (UNAM), the Central Veterinary Laboratory (CVL, Windhoek, Namibia) and the Friedrich-Loeffler-Institute (FLI), Germany have demonstrated that a single dog can be successfully immunized with a single vaccine bait.

As a result, DVS Namibia in collaboration with the Friedrich-Loeffler-Institute, Germany,  conducted a pilot field trial in the Oshana and Omusati regions of Northern Namibia in 2020 through funds from the Global Health Protection Programme (GHPP) of the German Ministry of Health.

We are here at the forefront of field research to bring this novel tool into application in Africa and elsewhere. We are confident that this method can greatly contribute to the global aim of ending dog mediated human rabies by 2030

Dr. Thomas Müller, FLI.

The Friedrich-Loeffler-Institute is the German federal research institute for animal health. It serves as WOAH reference laboratory for rabies and is also WHO Collaborating Centre for Rabies Surveillance and Research.

A follow-up  field trial of ORV of dogs was conducted in the Zambezi region of Namibia in 2022 under the leadership of FLI, and was funded by WOAH with funds from the German Federal Ministry for Economic Cooperation and Development (BMZ, OHRT Project).

The Zambezi region of Namibia’s NCA covers an area of 14,785 km² and is mostly made up of swamps, floodplains, wetlands and woodlands. This epidemiologically rather isolated area makes it an ideal candidate for a sustainable elimination of dog-mediated rabies. With an estimated human population of about 142,000 and a dog population of 18,000 the achievement of a vaccination coverage of 70% appears feasible. However, no large-scale MDV had been conducted before 2022, and rabies cases also in humans prompted an emergency response using ORV only. During this initial trial, with four teams and within four working days, 3,097 dogs were offered a bait, of which 88% were considered vaccinated, vaccinating on average over 20 dogs per hour. The bait acceptance by dogs and successful vaccination as well as field applicability and effectiveness demonstrated the great potential of ORV in dogs rabies control programmes.

In June 2024, a large-scale ORV campaign in dogs was conducted for the second time in the Zambezi region. With the size and number of oral vaccine baits, this study represents the world’s largest field trial on ORV in dogs. During this ORV campaign, preferentially, higher density areas were targeted, as connectivity and transmission of rabies is more likely in those areas.

With 10 teams, each consisting of only two people, and within four working days, 7,982 dogs were offered a bait with about 45% vaccination coverage, marking a huge success. The success was based on high acceptance of ORV by dog owners, and they were surprised to see their dogs being vaccinated against rabies by offering a bait without injecting a vaccine using a needle-syringe, and also without a need to catch the dogs for vaccination. Awareness and education on rabies and ORV were also provided by each team. A mobile phone technology (WVS/Mission Rabies Mobile App) was used to capture and track the vaccination data, allowing for the visualisation of vaccination points on a map and for directing teams into uncovered areas to increase vaccination coverage. Loud hailers were used to increase awareness on rabies and vaccination during village visits and facilitate the success of the campaign.

Together with dog vaccination campaigns using central point vaccination (CPV) and vaccinations alongside with FMD cattle vaccinations carried out in 2023 when a total of 3,369 dogs were vaccinated, it is anticipated that the increased vaccination coverage fosters an elimination of dog-mediated rabies in the Zambezi region. Also, an assessment is planned for the post vaccination monitoring based on dog owner surveys. This survey will take place later this year and will encompass both the analysis of vaccination coverage and rabies incidence based on owner awareness. This will be contrasted on the one hand to the estimated vaccination coverage by geographic information systems (GIS) methods and laboratory-based surveillance data and for rabies surveillance also on the previous status as obtained during a knowledge, attitude, and practice (KAP) study. With these results the DVS is envisaging to further integrate ORV into the rabies control programme of Namibia

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