African Swine Fever Virus
The African Swine Fever virus, ASFV, is a double-stranded DNA virus that replicates in the cytoplasm of infected cells. It can affect most pigs, wild and domesticated, as well as soft ticks. It is the only virus with a DNA genome that is transmitted by arthropods.
The virus causes a lethal hemorrhagic disease in domestic pigs which sometimes leads to death in as little as a week. In every other species the virus causes no discernible disease.
The virus is endemic to Sub-Saharan Africa and exists in the wild through a cycle of infection between ticks and pigs. The virus was restricted to Africa until 1957 when the disease was reported in Portugal. In 1960 another outbreak occurred and later outbreaks occurred in France, Belgium, and the rest of Europe during the 1980s. By 1990 Spain and Portugal had eradicated the disease.
Sometime during the 1970s ASFV crossed Atlantic Ocean to the Americas. The most recent outbreak outside of Africa was in 2007 in the country of Georgia. ASFV appeared in the western hemisphere around the same time that AIDS did leading to speculation that they were related. Later AIDS was linked to HIV and there was no correlation between ASFV and AIDS. Usually there are 150 genes within the virus although this can differ slightly between different isolates of the virus.
It is similar to poxvirus, iridovirus, and mimivirus. The virus encodes enzymes required for replication and transcription of the genome including elements of a base excision repair system, structural proteins, and other proteins that are not essential for replication in cells. The replication of the virus is done in the perinuclear factory areas.