Authorities in Tanzania are still struggling to control an outbreak of Rift Valley Fever (RVF), a highly contagious viral disease that infects livestock and humans, which has spread to 10 of the country's administrative regions in four months and killed more than 100 people.

The United Nations World Health Organization (WHO) said on Wednesday that 264 human cases of RVF had been reported in Tanzania between mid-January and 3 May, with 109 of the patients having died.

The disease was first observed in January in the northern regions of Arusha and Manyara and by the end of March, cases of human and livestock infections and deaths were reported in Dar es Salaam, Dodoma, Iringa, Kilimanjaro, Mbeya, Morogoro, Singida and Tanga.

"Dodoma [central] was the worst affected as 50 people died and over 130 were admitted to health centres," said the Health Minister, David Mwakyusa.

Veterinary officials have since reported that an ongoing livestock vaccination campaign has stemmed the spread of the disease. Control efforts included restrictions on livestock movement and, in some parts, a ban on the consumption of beef.

Health officials said the campaign had been successful, citing a reduction in the number of new cases in hospitals. In Dodoma, for example, 35 people had been admitted to health facilities by 6 May, down from more than 100 on 28 March.

Vaccination campaign
Tanzanian authorities imported RVF livestock vaccines from South Africa in February and embarked on a vaccination campaign. President Jakaya Kikwete said in March it would cost US$12.3 million.

An awareness campaign, particularly among pastoralist communities, met with a positive response. In Dodoma, veterinary officials repeatedly reported a shortage of vaccines as large numbers of livestock keepers drove their herds to vaccination centres.

Samson Muniko, regional veterinary officer of Dodoma, told IRIN on Wednesday that the region's herd of 1,194,878 cattle, 954,000 goats and 294,572 sheep needed vaccination and tick-control chemicals worth $290,000, but so far only vaccines and chemicals valued at about $56,345 had been received.

RVF has led to a significant reduction in the consumption of red meat in the affected regions and surrounding areas. Incomes of livestock dependent communities have dwindled as a result.

"I used to sell more than 500kg of meat every day, but now I can hardly sell 100kg," said Rashid Khalfan, who operates a butchery in Kisutu, Dar es Salaam.

The past four months have witnessed a sharp rise in the price of fish and chicken in Dar es Salaam and other RVF-affected regions as demand soars.

Cases in Kenya and Somalia
In neighbouring Kenya, a total of 684 cases of RVF, including 155 deaths, were detected between 30 November 2006 and 12 March 2007, according to WHO. About 333 cases were reported in the Northeastern Province and the rest in the Rift Valley, Coast, Central and Eastern provinces.

The disease has also hit Somalia, with 114 cases, including 51 deaths, reported in Juba, Gedo, Hiran, Middle Juba, Middle and Lower Shabelle regions between 19 December 2006 and 20 February 2007.

The RVF virus is spread to humans from livestock via the aedes mosquito, which breeds rapidly during floods. It can be transmitted through contact with infected animal material, such as blood 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.