April 29, 2013

EFSA examines risk of Rift Valley fever spreading to the Mediterranean

Rift Valley fever is likely to be introduced into countries in North Africa and Middle East that border the Mediterranean Sea through uncontrolled movements of infected animals from Eastern Africa and the Arabian Peninsula, reveals the EFSA's (European Food Safety Authority) Panel on Animal Health and Welfare (AHAW).

Rift Valley fever is a highly contagious disease that affects animals and humans, potentially leading to death. It is transmitted through mosquitoes and contact with blood or tissues of infected animals. With important implications for animal and human health, Rift Valley fever also impacts people's livelihood, the trade of animals and food security.

Based on the available evidence in scientific literature and outbreak reports, the AHAW panel concluded that in the last 10 years, Rift Valley fever has not spread to new countries. The panel noted, however, that the disease has moved north within Mauritania to a desert area.

Looking at the geographical distribution of the mosquitoes that transmit this virus, the AHAW Panel found that the southern Mediterranean region provides favourable climatic (rain and temperature) and environmental conditions for the presence of the disease vectors, especially in summer and autumn.

In case of an outbreak, the disease could be introduced into countries of North Africa and the Middle East by infected animals moving north from East Africa or through the Arabian Peninsula. Other less likely pathways are animal movements from Central and West Africa. The panel developed a model to assess and quantify the risk of entry of the Rift Valley fever virus in North Africa and the Middle East in case of an outbreak. Experts found it less likely that the Rift Valley fever virus would be introduced through the movement of mosquitoes than by infected animals.

The opinion also highlighted that were a Rift Valley fever outbreak to occur in countries in North Africa and Middle East, the disease would potentially spread along the coastal areas and the Nile Delta, due to the density of livestock and presence in this area of mosquitoes that can transmit the virus.

To protect Europe and the neighbouring Mediterranean countries against the possible introduction and spread of Rift Valley fever, the AHAW Panel made several recommendations. Effective surveillance, monitoring and reporting tools need to be developed to better detect changes in the occurrence of the disease in animals. Further investigations are required to map seasonal variations in the presence of mosquitoes and better understand the effectiveness of these vectors in transmitting the disease. Efforts should also be made to monitor the possible movement of animals into North Africa and Middle East.