Tropical Livestock Diseases Invade Temperate Zones

ROME - Oct 8/07 - SNS -- Governments need to invest more in surveillance and control measures for animal diseases such as bluetongue, warns the United Nation's FAO.

"No country can claim to be a safe haven with respect to animal diseases," said FAO Chief Veterinary Officer Joseph Domenech.

"Transboundary animal diseases that were originally confined to tropical countries are on the rise around the globe. They do not spare temperate zones including Europe, the United States and Australia," he added.

Globalization, the movement of people and goods, tourism, urbanization and probably also climate change are favouring the spread of animal viruses around the planet.

"The increased mobility of viruses and their carriers is a new threat that countries and the international community should take seriously. Early detection of viruses together with surveillance and control measures are needed as effective defence measures," Domenech said.

"This requires strong political support and funding for animal health and more adequate veterinary services. Many countries are still not prepared to deal with this new threat."

Examples of human and animal disease agents that were previously mainly found in tropical regions and that have spread internationally include: West Nile Virus, transmitted by mosquitos, carried by birds and sometimes affecting also humans; Leishmaniasis, a parasitic disease that spreads through the bite of infected sand flies; and tick-borne Crimean Congo Haemorrhagic Fever. African horse sickness, a disease transmitted by the same midges that also carry bluetongue, may follow soon. African swine fever has recently reached Georgia and Armenia and poses a threat to neighbouring countries.

Mosquitos that can transmit major human diseases such as yellow fever, dengue and chickunguya have already reached European countries and may constitute a major public health concern.

The non-contagious bluetongue virus affects all ruminants (cattle, goats, deer and sheep) although symptoms are generally more severe in sheep. The virus, spread by Culicoides insects, is not transmitted directly between animals and does not affect humans.

Bluetongue was first discovered in South Africa but has spread to many countries. It had crossed the Mediterranean by the end of the 1990s. Since the summer of 2006, the virus has been found in Belgium, Germany, Luxemburg, the Netherlands and the north of France and most recently in the UK.

The reason why bluetongue has spread to northern Europe remains unclear. The virus is apparently adapting to new local insect carriers of the Culicoides genus which survive cold temperatures.

"We never expected that the bluetongue virus could affect European countries at such high latitudes," said FAO Animal Health Officer Stephane de la Rocque. "The virus is already endemic in Corsica and Sardinia but could also persist in northern European countries."