Livestock vaccination stems spread of RVF

An ongoing livestock vaccination campaign against an outbreak of Rift Valley Fever (RVF) has stemmed the spread of the disease in Kenya, where the mosquito-borne illness, which affects both animals and humans, has killed 154 people since December 2006, officials said on Tuesday.

"We have not received any new (livestock) cases although our extension officers are still carrying out surveillance in the affected districts," said William Maritim, senior veterinary officer with the disease control unit of the Ministry of Livestock and Fisheries.

At least 1.5 million livestock (cattle, sheep, and goats) are targeted for vaccination in the ongoing campaign in 33 districts where RVF cases have been reported. The worst affected districts were Garissa, Ijara and Wajir in Northeastern Province, Tana River and Kilifi districts in Coast Province, and Kirinyaga and Maragwa districts in Central Province.

"We are also in the process of procuring an additional 750,000 doses of vaccine to sustain the exercise," Maritim said.

The vaccination project, which began in Garissa on 8 January, is moving towards the Rift Valley Province, where the disease was first reported in 1931. RVF causes spontaneous abortions and death in animals.

Most of the vaccines have been imported from South Africa at approximately US$0.37 a dose.

The RVF virus is spread to humans from livestock via the aedes mosquito, which breeds rapidly during floods. The Northeastern Province, inhabited by nomadic pastoralists, was hit by devastating floods in the last three months of 2006 after heavier than normal rainfall.

It can be transmitted through contact with infected animal material, such as blood or other body fluids, or organs. Consumption of milk, a staple for many pastoral people, is also thought to lead to infection. Symptoms in humans include bleeding through the nose and mouth, and liver failure.

The government imposed a ban on the slaughter of livestock in the affected areas when RVF was first reported, leading to the closure of livestock markets in a region where people depend on animals for income and food. The ban has since been lifted, but a restriction on livestock movement is still in force.

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