Screening sandflies for natural infection with Leishmania donovani, using a non-radioactive probe based on the total DNA of the parasite

Digoxigenin-labelled total, Leishmania donovani DNA was used as a probe to detect the parasite in Indian Phlebotomus argentipes. The probe was quite s ensitive, detecting as Little as 0.3 pg parasite DNA, equivalent to approxi mately 100 parasites. Positive signals could be detected in 12 (32%) of the 38 small (two- to 30-fly) pools of the wild-caught P. argentipes investiga ted and in a pool of 10 laboratory-bred P. argentipes fed on a patient with post-kala-azar dermal leishmaniasis. None of the wild-caught P. papatasi, P. sergenti or Sergentomyia sp. or of the newly emerged, laboratory-bred P. argentipes investigated were positive by this probe. The results indicate that such a probe may be very useful in screening sandflies for L. donovani , and so detecting the main vectors and transmission pathways of this paras ite, in India and elsewhere.