Rabies in Kudu - Namibia

NOTES ON KUDU AND RABIES

Spreading

The first confirmed outbreak of rabies in Africa, believed to have followed the importation of an infected dog from England in 1892, occurred in the eastern Cape Province of South Africa, and was brought under control in 1894.
An unconfirmed epidemic of rabies in dogs occurred in western Zambia in 1901. By the following year the disease had apparently spread along a major trade route, to cause an outbreak in Zimbabwe which engulfed most of the country before being eradicated in 1913.
The existence of endemic rabies of viverrids (mongooses and genets) was confirmed in South Africa in 1928, and since then the viverrid disease has continued to occur widely on the interior plateau of the country with spill-over of infection to cattle and a variety of other animals.
From about 1947 onwards, an invasive form of dog rabies spread from southern Zambia and/or Angola into Namibia, across northern and eastern Botswana into Zimbabwe and the northern Transvaal by 1950, entered Mozambique in 1952, and spread from there to Swaziland in 1954.
Dog rabies extended from southern Mozambique into Natal in 1961 to cause a major epidemic which was brought under control in 1968.
The disease re-entered northern Natal from Mozambique in 1976 and since then dog rabies has proved difficult to control in the peri-urban settlements of Natal-KwaZulu.
The disease spread from Natal to Lesotho in 1982, and into the Transkei region of the eastern Cape Province in 1987, to reach the Ciskei by 1990.
The spread of the disease in dogs was followed by the emergence of rabies of jackals and cattle in central Namibia, northern Botswana, Zimbabwe and the northern Transvaal.
A unique outbreak of rabies in kudu antelope occurred in central Namibia from 1977 to 1985, apparently involving oral spread of infection between individuals.
A few cases of rabies in the bat-eared fox were recognized each year in Namibia from 1967 onwards, and from the 1970s the occurrence of the disease in the fox has emerged as a distinct problem in the northern Cape Province and spread to the west coast. The rabies-related viruses, Lagos bat, Mokola and Duvenhage, associated with bats, shrews and rodents in Africa, are known to have caused isolated cases of disease in South Africa, and on one occasion a small outbreak involving six cats and a dog in Bulawayo, Zimbabwe. (HNets Humanities & Social Sciences Online July 2007).

Namibia Professional Hunting Association (NAPHA) affiliated sources revealed the contagion was initially detected at a farm in the Wilhelmstal area before it spread north via farms at Omaruru, Otjiwarongo and then it spread eastwards and scattered southwards. (Africa Hunting, Safaris News, 2006).

“Namibia Professional Hunting Association sources revealed the contagion was initially detected at a farm in the Wilhelmstal area before it spread north, east, and scattered south. Cases have been reported at Omitara. From there it spread toward Botswana,” Inambao added. “Some farms around Windhoek have also reported cases of kudu frothing at the mouth and not being afraid of people.”(ANIMAL PEOPLE, June 2006).

There is a precedent for a rabies outbreak among Namibia kudu. Recalled three moderators of the International Society of Infectious Diseases’ ProMed electronic bulletin board, in a joint posting, “A unique outbreak of rabies in kudu began in central Namibia in 1977, apparently involving oral spread of infection between individuals. It peaked in 1980 and eventually subsided in 1985, by which time it had caused an estimated loss of 30,000 to 50,000 antelope, or 20% of the population.” But the report drew skepticism from rabies expert Henry Wilde, M.D., of the Queen Saov-abha Memorial Hospital in Bang-kok, Thailand. “Herbivore to herbivore transmission would be unlikely,” Wilde told ANIMAL PEOPLE, explaining that the Namibian climate would quickly kill any live rabies virus in dripping saliva from the victim animals. “The most likely explanation is that there is another epidemic disease that causes most of the kudu deaths, and/or that a small undetected biting mammal is the vector for the kudu rabies cases,” Wilde said. (ANIMAL PEOPLE, June 2006).

A team of British, Namibian, and South African researchers headed by Karen Mansfield of the World Health Organization reported in January 2006 that “37 rabies virus isolates…originating mainly from the northern and central regions of Namibia between 1980 and 2003… suggest that jackal and kudu may form part of the same epidemiological cycle of rabies,” with the predators apparently doing the actual disease transmission. (ANIMAL PEOPLE, June 2006). (Article Attached as word document).

Magnitude

One 12 000-hectare farm suffered game losses of 400 beasts over the past two years (Africa Hunting, Safaris News, 2006).

Sources are saying the present outbreak (2006) whose magnitude compares to the contagion that affected the game industry over a seven-year wave in Namibia lasting from 1975 to 1982, is being caused by kudu populations that have increased over the past several years (Africa Hunting, Safaris News, 2006).

In Namibia, the major rabies epidemic reported in greater kudu in 2002 (estimated 2,500 cases) continues to smoulder. During 2003, 23 kudu specimens submitted were positive on fluorescent antibody test. In addition, 22 cases were confirmed in black backed jackal (Canis mesomelas), 3 cases in honey badgers (Mellivora capensis), 2 cases in hyaena (Crocuta crocuta) and one each in cheetah (Acinonyx jubatus), suricate (Suricata suricata), Eland (Taurotragus oryx) and common duiker (Sylvicapra grimmea). (World Animal Health – 2003).

New Era was told kudus that have weakened immunity to rabies when compared to dogs and other animals get infected by eating affected vegetation, while the virus could also get into their bodies through lesions in their mouths caused by shrubs and thorns (Africa Hunting, Safaris News, 2006).

A thorough investigation into kudu characteristics revealed that the kudu population had increased disproportionally before the epizootic (1977 – 1988) in response to favorable conditions. The social behavior of the kudu, i.e., group browsing on acacia trees, whose thorns cause lesions in the kudu's oral cavity, as well as the excretion of relatively high titers of virus in the saliva of infected animals provide suitable conditions for transmission in the kudu population after initial infection through the jackal or other species. (Central Veterinary Laboratory, Windhoek, Namibia 1988)

The titres of rabies virus in the saliva of kudu are higher than those of the salivary glands. The high titres are an indication of active excretion and multiplication in tissues other than the salivary glands. Two out of 4 kudu died of rabies after experimental infection by the instillation of infected saliva onto their buccal and nasal mucosae. Mice and 2 cattle resisted a similar exposure. Kudu also developed antibodies against rabies after instillation of HEP Flury virus onto their nasal and buccal mucosae. Cattle did not react when they were treated in the same way. These results suggest a high susceptibility of kudu to rabies when the virus is applied to their mucous membranes. (Onderstepoort journal of veterinary research - Created 1983/09/09; Completed 1983/09/09; Revised 2003/11/14).

Symptoms

If the virus infects kudu with an incubation period varying from 21 to 365 days it tends to hang its head lower but the most important clinical characteristic of the preliminary phase is behavioural change during which the animal appears tame, salivates excessively, loses appetite, and urinates frequently. After this phase sick animals may either become aggressive or show signs of paralysis (Africa Hunting, Safaris News, 2006).

There was one strange case in which this beast had to be shot inside a house and one farmer who requested anonymity cited several cases of rabid kudu. (Africa Hunting, Safaris News, 2006).

Hunting Industry

Veterinarians Otto Zapke and Beate Voights in mid-May 2006 reportedly confirmed that a rare outbreak of rabies spreading from herbivore to herbivore during the past two years was responsible for the deaths of “thousands” of kudu in the Omaruru region of Namibia. (ANIMAL PEOPLE, June 2006).

About 5,000 hunters per year visit Namibia. (ANIMAL PEOPLE, June 2006).

With over 5 000 trophy hunters, the hunting industry directly generates N$100 million for the country each year and N$200 million is generated indirectly as secondary revenue. (Africa Hunting, Safaris News, 2006).

Dr Zapke said the Okahandja and Windhoek areas are showing more prevalence of rabies, while Dr Voights said there is a tendency among farmers not to report cases of the deadly viral disease that can affect all warm-blooded animals and has various known strains. (Africa Hunting, Safaris News, 2006)

Meat

The meat from the affected animals can be consumed provided the necessary precautions are taken (Africa Hunting, Safaris News, 2006).