Zebra rabies case highlights wildlife risks, say Kenyan researchers


zebra-lewisResearchers suggest there is a need for increased reporting of animal bites and sharing of data over suspected rabies cases between public health, wildlife and veterinary authorities in Kenya after a young zebra kept at a safari lodge died from the dangerous infection.

Mark Obonyo and his colleagues reached the conclusion after their investigation into staff exposure and animal bite surveillance in the wider district after detection of the rabid zebra at the safari lodge in Kenya in 2011.

Their findings have been published in the Pan African Medical Journal.

Rabies is a fatal viral infection, resulting in more than 55,000 deaths globally each year. It is usually transmitted in the saliva from the bite of an infected animal.

In August 2011, a young orphaned zebra at a Kenyan safari lodge acquired rabies after being bitten on the muzzle by a feral dog and died a month later. The zebra potentially exposed more than 150 tourists and local staff.

The rabies diagnosis was laboratory-confirmed by a fluorescent-antibody test.

There was an immediate health concern given that both staff and guests at the lodge had opportunities for physical contact with the zebra.

The researchers said the one-month-old zebra had been adopted by the mobile safari company associated with the safari lodge in January 2011. It was kept within the stables, which was home to 36 horses, and it was free to mingle with the horses and other stable animals, staff, and lodge guests.

The zebra had not been vaccinated against rabies.

The zebra had become an attraction to tourists visiting the mobile safari and the lodge, and many participated in feeding, petting, and taking photographs with the zebra.

Following its death, the lodge distributed a statement by email to guests from several countries around the world, alerting them of the possible exposure to the rabies virus, and recommending that individuals seek medical advice.

On September 1, 2011, the US Centers for Disease Control and Prevention (CDC) received reports from two state health departments regarding the need for post-exposure preventative treatment among American tourists that had visited the lodge.

The CDC immediately contacted the Kenyan Ministry of Public Health and Sanitation, and the event was reported to the World Health Organisation.

A multinational investigation among US and other international tourists who visited the affected lodge was initiated to ensure that travelers potentially exposed to the rabies virus received appropriate preventative treatment.

In Kenya, an investigation was initiated to determine exposures among the local staff, and to explore animal bite surveillance in the affected district.

Obonyo and his colleagues interviewed lodge staff on the circumstances surrounding the zebra’s illness and assessed their exposure status. They also reviewed animal bite report forms from the outpatient department at the district hospital.

The zebra was reported bitten by a dog on July 31, 2011 and became ill on August 23. It died three days later.

There were 22 employees working at the lodge during that time. Six (27 percent) had high exposure due to contact with saliva (bottle feeding, veterinary care) and received four doses of rabies vaccine and one of immune-globulin, and 16 (73 percent) had low exposure due to casual contact and received only four doses of rabies vaccine.

From January 2010 to September 2011, 118 cases of animal bites were reported in the wider district. Domestic and stray dogs accounted for 98 percent of reported bites, the researchers found.

In their conclusions, the researchers said their investigation highlighted the fact that, in Kenya, human exposure to the rabies virus can occur from contact with wildlife.

“However, such exposures are rarely reported and not well documented in Kenya.

“Wildlife in Kenya accounts for less than 1 percent of reported rabies cases in animals, suggesting that rabies in wildlife is under-reported.

“Our evaluation of animal bite surveillance in the affected district showed that bites from owned dogs continue to be a major public health problem in Kenya, leading to potential rabies virus exposures in the population.

“Though rabies virus exposures from owned dog bites continue to be a challenging problem in Kenya, the large-scale exposure of staff and guests at a safari lodge highlighted that non-canine wildlife species can also become infected with rabies virus and pose an exposure risk.”

They concluded there was a need for increased reporting of animal bites and sharing of data regarding suspected rabies cases between public health, wildlife and veterinary authorities in the country.

Mark Obonyo, Wences Arvelo, Samuel Kadivane, Moses Orundu, Emily Lankau, Francis Gakuya, Peninah Munyua, Jane Githinji, Nina Marano, Kariuki Njenga, Jared Omolo, Joel Montgomery. Investigation to determine staff exposure and describe animal bite surveillance after detection of a rabid zebra in a safari lodge in Kenya, 2011.  The Pan African Medical Journal. 2014;19:10

The full study can be read here

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