African Swine Fever, it is never too late to face the enemy

African Swine Fever (ASF) is a fatal viral hemorrhagic disease of domestic pigs and wild boar. There is no treatment or vaccine against it and the only control measures currently in place are based on a combination of early diagnosis and emptying of affected farms.

ASF is present in some countries in Europe and also reached China, Mongolia, and Vietnam before entering other areas of Europe and Asia. ASF virus (ASFV) was also detected in South America and even if North America has always been considered free from ASF, some experts warn that it may have arrived there too.

Africa is the origin of ASF, coinciding with the first introduction of domestic pigs from Europe at the beginning of the last century. Initially, ASF was thought to be a variant of classical swine fever (CSF), but after a series of studies, it was concluded that these were different diseases, as pigs that had overcome CSF were not protected against ASF. In the 1930s, the causal agent, the ASFV, was isolated:

It is the only member of the Family Asfarviridae

It is a virus with a double chain of DNA (two-stranded), of approximately 170-193Kb, which codes for more than 150 proteins.

ASFV is highly resistant to the environment, facilitating its survival for months if the humidity conditions are appropriate.

Livestock trucks or farm boots contaminated with infected blood can simply serve as a trigger to spread the virus.

ASFV – A VIRUS WITH A COMPLEX CYCLE

WILD CYCLE

African wild pigs such as warthogs (Phacochoerus africanus or Phacochoerus aethiopicus) and bushpigs (Potamochoerus larvatus) are the natural asymptomatic hosts of ASFV, i.e. they do not manifest the disease.

ASFV also infects arthropods, specifically soft ticks of the genus Ornithodoros, which are capable of vertically transmitting the virus to their progeny.