Experimental transmission of African swine fever virus by Ornithodoros lahorensis (Acari: Argasidae)

African swine fever (ASF) is an acute, highly contagious infectious disease that affects both domestic and wild pigs, caused by the African swine fever virus (ASFV). ASFV is the only known DNA virus transmitted by arthropod vectors, with acute infection in pigs leading to morbidity and mortality rates as high as 100%.The virus can persist in a transmission cycle among wild boars, soft ticks, and domestic pigs. To date, nine Ornithodoros spp. have been confirmed to be capable of transmitting ASFV worldwide. However, the potential soft tick species capable of transmitting ASFV in China remain unclear. In this study, we compared the ability of Argasidae spp. Ornithodoros lahorensis and Argas persicus, as well as Ixodidae spp., Haemaphysalis longicornis, Rhipicephalus sanguineus and Dermacentor silvarum, to transmit ASFV via animal transmission experiments. The results revealed that O. lahorensis soft ticks, but not A. persicus or Ixodes, could act as competent vectors through transstadial and transovarial transmission of ASFV. The virus titers horizontally transmitted ASFV to ticks were 105.83, 106.59 and 104.31, HAD50/ml respectively. These viruses were detected in the nymphs developed from larvae, adults developed from nymphs, and larvae hatched from eggs by adults. Thus, O. lahorensis ticks are likely an important natural vectors of ASFV, although both mammalian and tick hosts are likely required for the maintenance of ASFV in the sylvatic cycle.