Issue of the Week: Kudu Rabies

2012-09-20 03.14.40

Kudu, a species of African antelope, are one of the main attractions for tourists in Namibia. Kudu are large, elk-like creatures with thin white stripes across their backs and are over 5 feet tall. The males have long spiraling horns that can grow over 4 feet in length. They are a very important source of meat for rural communities and their survival is crucial to the livelihoods of Namibian citizens. Farmers, ranchers, conservancies and those in the tourism and hunting industry benefit from the opportunity to utilize Kudu.

Recently, an increase in rabies found in Namibian Kudu populations has raised concern. Rabies is typically associated with carnivores, but does appear in non-carnivore species due to a “spill-over effect,” meaning that if an infected carnivore bites a non-carnivore species the rabies usually meets a dead end within the non-carnivore host.

However, in 1977 the first outbreak of this disease surfaced among kudu, which is a non-carnivore species. Even more troubling, the disease seems to resurface periodically among the kudu species specifically in Namibia, severely threatening this important resource.

According to a letter written by the Livestock Producers’ Organization of Namibia during the first rabies outbreak from 1977 to 1986, somewhere between 30,000 and 50,000 kudu died due to the disease.

The current outbreak began in 2002 and is still causing declines in Namibia’s kudu. In May 2004, one conservancy reported a 35 to 50 percent loss. In 2008, 50 percent of the Conservancy Association of Namibia (CANAM) reported losses ranging between 25 and 70 percent. From 2008 to 2010, 12 farms in the Otavi and Tsumeb areas showed kudu declines ranging from 30 percent to 68 percent, with an average of 46 percent decline.

kudu

Biologists have speculated that the disease is being maintained within the Namibian kudu population and is being transferred from kudu to kudu. This means that a specific strand of rabies unique to the kudu found in Namibia can be passed from animal to animal, likely through their blood, saliva, or other bodily fluids.

In the 2012 study Full Genome Analysis of Rabies in Namibian Kudu, researchers found that “several unique mutations were observed in the rabies strands isolated from kudu, suggesting that these mutations may have occurred due to the adaptation of the virus to the host.” The report explains that this evidence strongly supports the theory that Namibian kudu have maintained a unique strand of rabies as it evolved from the “traditional” carnivore-related rabies spill over. Further experimentation is still necessary.

Many worry that these large periods of loss combined with the possibility of a new strand of the disease will affect Namibia’s ability to maintain a sustainable kudu population. Multiple studies are underway to explore the nature of the disease and to discover a vaccine. A vaccination would put an end to the mass loss of kudu in Namibia and ensure that the strand does not spread to other geographic locations in Africa.

The ramifications of this disease, should it continue to spread, could be disastrous for Namibia with serious ecological and economic impacts. In order to curb these impacts, it is crucial that biologists gain a better understanding of the disease and the adaptations it has made. This will allow proper management of the disease to be implemented and will open the door for solutions to rabies associated with carnivores, which is a more widely circulated problem throughout Africa as well as worldwide.

Twice a week, SCI Foundation informs readers about conservation initiatives happening worldwide and updates them on SCI Foundation’s news, projects and events. Tuesdays are dedicated to an Issue of the Week and Thursday’s Weekly Updates will provide an inside look into research and our other science-based conservation efforts. Follow us on Facebook and Twitter for more SCI Foundation news.

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