INVESTIGATIONS ON THE IN VITRO FEEDING AND IN VITRO BREEDING OF THE HUMAN BODY LOUSE PEDICULUS HUMANUS CORPORIS (ANOPLURA: PEDICULIDAE)

Abstract:
The human body louse Pediculus humanus corporis - the main vector of both human spotted fever (rickettsiosis) and relapsing fever (borreliosis) - is maintained for insecticide efficacy tests and is commonly reared on rabbits as substitute hosts. A membrane feeding technique may offer a return to the natural nutrition medium of body lice - human blood - for feeding and reproducing these host specific human parasites. P. humanus corporis, derived from a rabbit adapted strain, were offered preserved human blood through a Parafilm M® membrane (American National Can, Chicago) at 38 °C. The superimposed blood, stemming from a blood bank, contained a CPD stabilizer. Subsequent to initial experiments on nutrition media and storage condition, P. humanus corporis were reared continuously for a nine-month period until adults of the 9th generation emerged. Lice regularly showed a feeding rate of more than 90% and a low mortality rate on day one after nutrition. Engorging time became shorter, from about 90 min (generation 1) to 15-30 min (generation 5), similar to the engorging time of P. humanus corporis on rabbits. To conclude, preliminary results indicate that in vitro feeding could be an alternative method of breeding the human body louse. Membrane feeding saves laboratory animals and is therefore considered to be a contribution to animal welfare. Further studies are required to optimize the composition of the nutrition medium.