TY - JOUR
T1 - Transmission of Leishmania donovani in the Hills of Eastern Nepal, an outbreak investigation in Okhaldhunga and Bhojpur Districts
AU - Ostyn, Bart
AU - Uranw, Surendra
AU - Bhattarai, Narayan Raj
AU - Das, Murari L
AU - Rai, Keshav
AU - Tersago, Katrien
AU - Pokhrel, Yubraj
AU - Durnez, Lies
AU - Marasini, Baburam
AU - Van der Auwera, Gerard
AU - Dujardin, Jean-Claude
AU - Coosemans, Marc
AU - Argaw, Daniel
AU - Boelaert, Marleen
AU - Rijal, Suman
N1 - FTX
PY - 2015
Y1 - 2015
N2 - BACKGROUND: In the Indian subcontinent, Visceral leishmaniasis is endemic in a geographical area coinciding with the Lower Gangetic Plain, at low altitude. VL occurring in residents of hill districts is therefore often considered the result of Leishmania donovani infection during travel. Early 2014 we conducted an outbreak investigation in Okhaldhunga and Bhojpur districts in the Nepal hills where increasing number of VL cases have been reported.METHODOLOGY/PRINCIPAL FINDINGS: A house-to-house survey in six villages documented retrospectively 35 cases of Visceral Leishmaniasis (VL). Anti-Leishmania antibodies were found in 22/23 past-VL cases, in 40/416 (9.6%) persons without VL and in 12/155 (7.7%) domestic animals. An age- and sex- matched case-control study showed that exposure to known VL-endemic regions was no risk factor for VL, but having a VL case in the neighbourhood was. SSU-rDNA PCR for Leishmania sp. was positive in 24 (5%) of the human, in 18 (12%) of the animal samples and in 16 (14%) bloodfed female Phlebotomus argentipes sand flies. L. donovani was confirmed in two asymptomatic individuals and in one sand fly through hsp70-based sequencing.CONCLUSIONS/SIGNIFICANCE: This is epidemiological and entomological evidence for ongoing local transmission of L. donovani in villages at an altitude above 600 meters in Nepal, in districts considered hitherto non-endemic for VL. The VL Elimination Initiative in Nepal should therefore consider extending its surveillance and control activities in order to assure VL elimination, and the risk map for VL should be redesigned.
AB - BACKGROUND: In the Indian subcontinent, Visceral leishmaniasis is endemic in a geographical area coinciding with the Lower Gangetic Plain, at low altitude. VL occurring in residents of hill districts is therefore often considered the result of Leishmania donovani infection during travel. Early 2014 we conducted an outbreak investigation in Okhaldhunga and Bhojpur districts in the Nepal hills where increasing number of VL cases have been reported.METHODOLOGY/PRINCIPAL FINDINGS: A house-to-house survey in six villages documented retrospectively 35 cases of Visceral Leishmaniasis (VL). Anti-Leishmania antibodies were found in 22/23 past-VL cases, in 40/416 (9.6%) persons without VL and in 12/155 (7.7%) domestic animals. An age- and sex- matched case-control study showed that exposure to known VL-endemic regions was no risk factor for VL, but having a VL case in the neighbourhood was. SSU-rDNA PCR for Leishmania sp. was positive in 24 (5%) of the human, in 18 (12%) of the animal samples and in 16 (14%) bloodfed female Phlebotomus argentipes sand flies. L. donovani was confirmed in two asymptomatic individuals and in one sand fly through hsp70-based sequencing.CONCLUSIONS/SIGNIFICANCE: This is epidemiological and entomological evidence for ongoing local transmission of L. donovani in villages at an altitude above 600 meters in Nepal, in districts considered hitherto non-endemic for VL. The VL Elimination Initiative in Nepal should therefore consider extending its surveillance and control activities in order to assure VL elimination, and the risk map for VL should be redesigned.
U2 - 10.1371/journal.pntd.0003966
DO - 10.1371/journal.pntd.0003966
M3 - A1: Web of Science-article
C2 - 26252494
SN - 1935-2727
VL - 9
SP - e0003966
JO - PLoS Neglected Tropical Diseases
JF - PLoS Neglected Tropical Diseases
IS - 8
ER -