The history of ASF outbreaks in Europe highlights the factors affecting spread as well as the challenges for eradication. In regions with mainly housed commercial pig production, spread was successfully prevented in the past through strict animal movement control and implementation of culling policies, states an article in the U.S. National Library of Medicine, National Institutes of Health. In contrast, extensive pig production systems with poor biosecurity facilitate the establishment of the disease in the first place, as was seen in Portugal and southwest Spain in 1960.
The presence of soft ticks of the genus O. erraticus and the close contact of wild boar with domestic pigs further hindered efficient disease control in these areas, the NIH report states.
“In the northeast of Spain, where intensive pig husbandry is predominant, the disease spread quickly with devastating consequences for the whole production sector. However, in this part of the country, control measures have proven to be more successful and with the introduction of a comprehensive national eradication program in 1985, 96% of the country was considered free of ASF within 2 years and disease persisted only in the southwest of the country.
Besides extensive monitoring activities, NIH reports the eradication program focused on improving biosecurity on farms, strict animal movement controls and increased disease awareness of pig farmers. Following an increase in reported outbreaks in 2004, the European Commission approved an eradication plan for Sardinia that included targeted surveillance and control in high-risk areas for wild boar and domestic pigs, stricter enforcement of biosecurity and increased control of export of pig meat products.
The importance of wildlife reservoirs for disease maintenance has been clearly demonstrated in the past and therefore the recent outbreaks in Georgia and the subsequent spread of the disease to Armenia, Azerbaijan and Russia are of great concern to the growing pig industry in many eastern European countries.
The situation has been further complicated and control options made more difficult by the spread of the disease into the local wild boar populations, says the World Organization for Animal Health.
Further west- or eastward spread of the virus would adversely affect the pig sector in many countries. The pig industry in the Ukraine is a growing agricultural sector, and many foreign investors are involved in its growth into large-scale pig farming. Although there aren’t a lot of backyard farms or free-ranging pigs, the presence of wild boar could lead to spread of ASF to Moldova, Romania, Hungary, Slovakia, Poland or Belarus, said the NIH report.