Rift Valley fever, JMS advisory June 2018

There has been an outbreak of Rift valley fever in Wajir and outlying areas, with reportedly 5 or more people killed. Rift Valley fever (RVF) is a viral infection that primarily affects animals but can also infect humans. Most human infections result from contact with the blood or organs of infected animals during slaughtering or butchering. Human infections can also arise from the bites of infected mosquitoes. Kenya has experienced outbreaks in the past, especially following El Niño rains and extensive flooding. Herders, farmers, slaughterhouse workers, and veterinarians are at higher risk of infection. Humans may also become infected by ingesting unpasteurized or uncooked milk of infected animals. There has been no evidence of outbreaks of RVF in urban areas.

The interval from infection to onset of symptoms varies from 2 to 6 days. Those infected either experience no detectable symptoms or develop a mild form of the disease with a fever of sudden onset, muscle pain, joint pain and headache. Some patients develop neck stiffness, sensitivity to light, loss of appetite and vomiting. A small percentage of patients develop a much more severe form of the disease with haemorrhage or bleeding.

Generally, no treatment is needed except for severe cases, where the predominant treatment is general supportive therapy.

Individuals residing or travelling to affected areas should take measures to prevent mosquito bites using impregnated mosquito nets, personal insect repellent, light coloured clothing (long-sleeved shirts and trousers) and avoiding outdoor activity in the evenings. Avoid handling of sick animals or their tissues or slaughtering. Desist from consumption of fresh blood, raw milk or animal tissue. All animal products (blood, meat, and milk) should be thoroughly cooked before eating. Outbreaks of RVF in animals can be prevented by a sustained programme of animal vaccination. The Government has banned the movement of livestock from the affected areas.