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The major part of the global burden of dog-mediated rabies falls on Africa and Asia, where still an estimated 60,000 people die of the disease annually. Like in many African countries, dog-mediated rabies is a major public health concern in Namibia, costing the country an estimated 242 human deaths during the past two decades, in particular in the Northern Communal Areas (NCAs). Consequently, under the “One Health” concept, the Namibian government adopted a National Rabies Control Strategy in 2015, which strives to contribute to the global goal of ending dog-mediated human rabies deaths by 2030. A key component of this strategy was the implementation a dog rabies elimination program in the NCAs in 2016, being designed as a stepwise regional rollout strategy by building on experience gained in a pilot project area. The area of implementation covers approximately 263,376 km2 and 64 constituencies, with around 1.2 million inhabitants and estimated 93,000 dogs.

Rabies in the Greater Kudu (Tragelaphus strepsiceros) in Namibia is unique and found in such magnitude as has not been reported elsewhere in southern Africa. Reasons as to why Kudus appear to be exceptionally susceptible to rabies still remain speculative at best. Because the current severe rabies endemic in Kudus continues to have an enormous negative impact on the Namibian agricultural sector, we set out to question existing dogmas regarding the epidemiology of the disease in a unique experimental setting. In addition, we explored effective measures to protect these antelopes. Although we were able to confirm high susceptibly of kudus for rabies and sporadic horizontal rabies virus transmission to contact animals, we contend that these observations cannot plausibly explain the rapid spread of the disease in Kudus over large territories. Since parenteral vaccination of free-roaming Kudus is virtually impossible, oral rabies vaccination using modified life virus vaccines with a high safety profile would be the ultimate solution to the problem. In a proof-of-concept study using a 3rd generation oral rabies virus vaccine construct (SPBN GASGAS) we found evidence that Kudus can be vaccinated by the oral route and protected against a subsequent rabies infection. In a second phase, more targeted studies need to be initiated by focusing on optimizing oral vaccine uptake and delivery.

Rabies is a fatal zoonotic disease that causes a heavy burden on societies. Namibia, a country in southern Africa, is aiming at controlling the disease in its main reservoir, the domestic dog. To facilitate the implementation comprehensive information on the ecology and epidemiology of the disease and surveillance is of utmost importance. The study presented assesses the baseline data for both human and animal rabies surveillance in Namibia in recent times and establishes correlations with ecological and socio-economic data in order to provide an up-to-date picture on the epidemiology of rabies in Namibia. For instance, it was important to identify the main drivers in the epidemiology, and whether the control strategy by mass vaccination of dogs is undermined by cycles of rabies in wildlife. Rabies in humans was reported mainly from the Northern Communal Areas (NCAs), with a total of 113 cases from 2011 to 2017, representing an incidence of between 1.0 and 2.4 annual human rabies deaths per 100,000 inhabitants. Kavango, the region with the highest human rabies incidence was also the region with the lowest animal rabies surveillance intensity. Generally, the vast majority (77%) of dog samples originated from communal farm land, followed by urban areas (17%), while only a small fraction (3%) was submitted from freehold farm areas. In contrast, kudu and eland submissions were almost exclusively from freehold farmland (76%) and urban areas (19%), whereas the submission of cattle samples was evenly distributed among freehold farms (46%) and communal farm land (46%). The likelihood of sample submission decreased exponentially with distance to one of the two laboratories. Overall, 67% (N = 1,907) of all samples submitted tested rabies-positive, with the highest positivity rate observed in kudus (89%) and jackals (87%). The transmission cycle of rabies in dogs appears restricted to the northern communal areas of Namibia, whilst rabies in wildlife species is predominately reported from farmland in central Namibia, mostly affecting kudu (Tragelaphus strepsiceros) and livestock with a likely reservoir in wildlife canids such as jackals or bat-eared foxes. The analysis confirms the presence of two independent transmission cycles in Namibia with little geographic overlap, thus allowing for a sustainable control of rabies in dogs in the NCAs., Author summary Rabies is a fatal zoonotic disease. It has been recorded in southern Africa including Namibia since the early 19th century. At present, Namibia is aiming at controlling the disease in its main reservoir, the domestic dog. This study assessed the baseline data for rabies surveillance in Namibia from 2011–2017. There are continuous reports of rabies in humans mainly from the Northern Communal Areas, with a total of 113 cases from 2011 to 2017. Among animal rabies submissions, the vast majority of canine samples originated from communal farm land, whereas kudu and eland submissions were almost exclusively from freehold farmland. Cattle samples were submitted evenly among freehold farms and communal land use. Those three species, i.e. dogs, cattle and kudus represent the animal species with the highest numbers of sample submissions and positives. Spatially, the transmission cycle of rabies in dogs appears restricted to the northern communal areas of Namibia, whilst rabies in wildlife species is predominately reported from farmland in central Namibia, affecting mostly the kudu (Tragelaphus strepsiceros). Given the spatial overlap of kudu and livestock rabies cases, an independent horizontal transmission cycle among kudus as previously suggested is highly unlikely. Rather, wildlife canids such as jackals or bat-eared foxes could be the reservoir for wildlife rabies in Namibia.