Experimental transmission of African swine fever virus by the tick Ornithodoros (Alectorobius) puertoricensis (acari : Argasidae)

The soft tick Ornithodoros puertoricensis Fox has been found on the Caribbean island of Hispaniola (Haiti and the Dominican Republic) where African swine fever (ASF) was endemic from 1978 to 1984. To evaluate the vector potential of O. puertoricensis for African swine fever virus (ASFV), second-instar nymphs were experimentally infected by feeding on a viremic pig that was infected with the Dominican Republic isolate (DR-II) of ASFV. Subsequent infection rates and mean virus titers for individually triturated ticks were: second-instar nymph (95.4%, 10(4.38 +/- 0.85)), third-instar nymph (48.9%, 10(4.59 +/- 0.61)), male (46.7%, 10(4.36 +/- 0.61)), and female (35.3%, 10(4.38 +/- 1.09)). Infected ticks transmitted ASFV to susceptible pigs by bite 23, 85, 126, 160, 182, and 239 d after the infective blood meal. These findings show that ASFV is passed transstadially among O. puertoricensis and that O. puertoricensis can be an efficient vector of African swine fever virus.