Detection ofLeishmania donovaniin Wild-Caught Phlebotomine Sand Flies in Endemic Focus of Leishmaniasis in Himachal Pradesh, India

Abstract

An endemic focus of cutaneous leishmaniasis (CL) is located in the Sutlej River Valley in Himachal Pradesh (India) in the north-western Himalaya where CL co-exists with visceral leishmaniasis (VL). In areas of the Indian subcontinent such as Rajasthan, cutaneous leishmaniasis is transmitted by Phlebotomus papatasi (Scopoli) and Phlebotomus salehi. In Himachal Pradesh, Phlebotomus longiductus (Parrot) is suspected to be the vector for CL. In the current study, sand flies were collected and tested for Leishmania infection and to confirm the vector species causing CL. Sand flies were collected during April and September of 2017–2019 from CL endemic villages of Rampur (Shimla), Nirmand (Kullu) and Nichar (Kinnaur) districts of Himachal Pradesh. The sand flies were identified as Phlebotomus (adlerius) longiductus (Parrot) and Phlebotomus (larrousisus) major (Annandale). The density of P. longiductus was found highest. The elevation of villages ranged from 947 m to 2,130 m and were far from the presence of subsoil water. Field collected sand flies tested positive (7.69%) for Leishmania donovani by PCR-RFLP. The L. donovani sequences detected from P. longiductus were 97% similar to L. donovani sequences reported from the cases of CL in Himachal Pradesh.The Leishmania positive sand flies were morphologically identified as Phlebotomus adlerious longiductus providing one step further evidence towards the vector status of CL in Himachal Pradesh. The findings of the study are of epidemiological significance for strategic planning of vector control for leishmaniasis in India.

Visceral leishmaniasis in the hills of western Nepal: A transmission assessment

“…One of the confirmed species from the same subgenus, P. (Adlerius) longiductus was found naturally infected with L. donovani and suspected to be the vector involved in cutaneous leishmaniasis transmission in Himachal Pradesh (India) in the north-western Himalaya. In this area VL and CL co-exist [28], as is the case in the western part of Nepal in recent years. Although the presence of L. donovani DNA in Phlebotomus (Adlerius) spp.…”

“…This is the very first report on these species in recent years from the western part of Nepal. Nonetheless, similar species were also observed to be present at high altitudes (947–2,130 m) in the bordering state of India [ 27 , 28 ]. Interestingly, we demonstrated the presence of L .…”

“…donovani and suspected to be the vector involved in cutaneous leishmaniasis transmission in Himachal Pradesh (India) in the north-western Himalaya. In this area VL and CL co-exist [ 28 ], as is the case in the western part of Nepal in recent years. Although the presence of L .…”