Attempts to transmit hepatitis B virus to chimpanzees by arthropods

Bedbugs (Cimex lectularius L.) were fed on an infective blood-hepatitis B virus (HBV) mixture. Further bedbugs and tampan ticks (Ornithodoros moubata [Murray]) were fed on HBV-carrier chimpanzees. After a 10-13 day interval for oviposition, tests done on samples of individual arthropods showed that 53-85% of the bugs were HBsAg-positive and none HBeAg-positive, while 100% of the ticks were HBsAg-positive and 88% HBeAg-positive. The remaining arthropods were fed on 3 susceptible chimpanzees, which had failed to develop HBV infection after 11 months, indicating no transmission had occurred. Subsequently the presence of viable virus in the original infective meals was confirmed by inoculation of the relevant donor sera directly into the 3 still susceptible chimpanzees. HBV infections quickly followed in each animal. It is concluded that, while mechanical transmission of HBV is most unlikely after a 10-13-day interval between feedings in bedbugs and tampans, it is still possible that mechanical transmission between humans might occur during interrupted feeds.