ASF REVIEW DIAGNOSIS VIDEOS DIAGNOSIS PROTOCOLS

Introduction Name Epidemiology Aetiology Pathogeny and Transmission Clinical Forms and Lesions
Differential Clinical Diagnosis Laboratory Diagnosis Prevention, Prophylaxis, Control and Eradication References & Authors Self Evaluation

Epidemiology

This disease was first described by Montgomery in Kenya, in 1921, when the virus spread from wild African suidae (phacochoerus aethiopicus) to European domestic pigs recently brought to the African continent, causing 100% mortality. During the following decades it was confined to Africa, until 1957 when it was detected in Lisbon, having spread from Angola, in the form of a peracute disease with almost 100% mortality.

In 1960, a new outbreak occurred near Lisbon which spread through Portugal and reached Spain in the same year. The disease was endemic in both countries, with different epizootic cycles, until 1995 when it was eradicated from the Iberian Peninsula (Portugal eradicated it in 1994, but in Spain the eradication programme took one more year, until 1995), after an exhaustive eradication programme.

Since no vaccine was available, the eradication program was primarily based on the detection of ASF-infected animals by laboratory diagnosis and the enforcement of strict sanitary measures. During the first four years of the program (1985-1989) (Pictures a & b), eradication was achieved in a big part of the country. However, the disease remained present in the south-west region of the country, where the extensive production of Iberian pig is located (Pictures c & d).

The eradication of ASF in this area was difficult, due to the continuous contact of these animals with ticks, reservoir of the disease; the low biosecurity level of this production in that moment, and the frequent contact of pigs with wild boars. Despite that, ASF eradication program was useful in Spain, and helped to improve biosecurity and sanitary measures in pig farms, especially in Iberian pig farms. This farms present nowadays an extensive production totally controlled, and from which is obtained the most famous product of Spanish gastronomy, the Iberian ham.

Since 1960, different European countries have been affected by ASF outbreaks: France (1964), Italy (1967, 1969, and 1993), Malta (1978), Belgium (1985) and the Netherlands (1986). Further outbreaks occurred in 1999 in Portugal, in the region of Alentejo, but were rapidly eradicated. African Swine Fever has been endemic on Sardinia since 1978 and eradicated in other countries. In this island, wild boars and recovered domestic pigs act as carriers and thus maintain the disease.

Different countries in the American continent have been affected by African Swine Fever: Cuba (1971, 1980), Brazil (1978), Dominican Republic (1978) and Haiti (1979). ASF has been eradicated in all of them.

Nowadays, ASF occurs in a large number of Sub-Saharan African countries, in most of them endemic. The disease is becoming increasingly important due to the increased number of outbreaks in the region. Some of these countries were free of the disease, like Madagascar (1998), Mauritius (2007), and West African countries like Benin (2001), Togo (1998), Nigeria (1998) or Ghana (1999).

There was a big change in the epidemiology of the disease in 2007, when ASF entered again in the European continent, by the Caucasus region.

First outbreaks of the disease occurred near the port of Poti (Georgia), by infected pork meat that was brought in international ships. From this area, ASF spread to the neighbour countries of Armenia, Azerbaijan and Russian Federation, causing huge economic looses.

Nowadays, ASF remains present in Russian Federation. The lack of control in the disease, the presence of infected wild boars, and the trade of animals and its product without control, could favor the maintenance and spread of the disease in that region.

The current situation of ASF spread in Africa and, specially, the presence of the disease in Caucasus region and its potential spread to the East European countries, obliges all countries to be prepared for the possible appearance of this disease in any part of the world, as a result of intensive world trade relations. Especially important is that situation in European Union, where the proximity with the affected area increases the risk of ASF introduction in their countries.