By Jeremy Clarke NAIROBI, Feb 6 (Reuters) - The death toll from a major outbreak of Rift Valley Fever in Kenya has risen to 139 and the highly-contagious disease has spread to neighbouring Tanzania, authorities said on Tuesday. Transmitted to humans through mosquito bites or close contact with contaminated animals, the disease first hit remote areas of Kenya in mid-December. Without any vaccine or treatment, the disease can cause severe haemorrhaging, leading the victim to vomit blood or even bleed to death. Weight loss and blindness are other symptoms in severe cases, Kenyan health officials said. Some cases have been found across Kenya's northern border in Somalia. Health officials in Tanzania, to the south of Kenya, confirmed on Tuesday they had registered the first two cases of Rift Valley Fever in nearly a decade. "These two people fell ill in different places. They arrived at the hospital, but both died on January 31. Symptoms showed they had Rift Valley Fever," Evans Balama, acting commissioner for Tanzania's Arusha region, told Reuters. In Kenya, where the disease has badly affected the important meat business, officials said the death toll had risen to 139 -- a rise of 21 in the last two weeks. Infections in Kenya peaked over the holiday period when heavy rains produced flood waters, providing breeding grounds for different species of mosquito. "Infection comes from touching the blood or bloody fluids of infected animals, from slaughtering or skinning these animals, from drinking their unboiled milk or from the bite of an infected mosquito," Health Minister Charity Ngilu said. Speaking at a news conference, Ngilu added distressed Kenyan farmers were calling her direct on her mobile phone to report sick animals. She urged Kenyans to eat their beef well cooked, avoid touching sick or dying animals and sleep under treated mosquito nets. A similar outbreak of Rift Valley Fever -- named for the vast geographical fissure spreading from Syria down east Africa to Mozambique -- killed hundreds of Kenyans in 1997-1998. (Additional reporting by George Obulutsa in Dar es Salaam)
