Cameron, Mary

Campino, Susana

Cloots, Kristien

Hasker, Epco

Kristan, Mojca

Kumar, Ashish

Kumar, Kundan

Kumar, Vijay

Malaviya, P

Mark-Carew, Miguella

Singh, AK

Singh, OP

Sundar, Shyam

LSHTM Research Online

543O39-04: COMBINING HUMAN SEROSURVEILLANCE WITH MOLECULARXENOMONITORING IN TWO ENDEMIC VILLAGES FOR VISCERALLEISHMANIASIS SURVEILLANCE IN SARAN, BIHAR, INDIAMiguellaMark-Carew1, Kristien Cloots2, SinghOP3, Singh AK3, MalaviyaP3, Epco Hasker2, Susana Campino1, Mojca Kristan1, Kundan Kumar4,Ashish Kumar4, Vijay Kumar4, Shyam Sundar4 and Mary Cameron11London School of Hygiene and Tropical Medicine (LSHTM), London, UnitedKingdom; 2Institute of TropicalMedicine (ITM), Antwerp, Belgium; 3BanarasHindu University (Varanasi, India); 4Rajendra Memorial Research Instituteof Medical Sciences (RMRIMS), Patna, IndiaAs India prepares for post-elimination of visceral leishmaniasis (VL), it willbecome much harder to detect human cases, especially if case numbersdecrease further or occur in new areas with limited or no surveillanceactivity. New strategies for surveillance are required, monitoringtransmission rather than disease, and targeting both humans and the sandfly vector, Phlebotomus argentipes. In 2019, researchers in the SPEAK Indiamolecular xenomonitoring (MX) and surveillance workpackages focused VLdetection efforts in endemic villages of Bishambharpur and Rampur Jagdish(having reported VL cases in each of the 3 years prior to the study, i.e. 2016-2018) in the Saran district of Bihar, India. The goal of this workwas to assesswhether a combined human serological and MX approach allows fordetection of ongoing VL transmission. For MX, field teams set 10 CDC lighttraps in each village every fortnight in households that consented toparticipate in the study from June to September 2019. Sand flies were firstsorted fromother vectors (i.e. mosquitoes) then by sex andgenus and storedat -20 C. They were later dissected and stored as individual heads andpooled thorax-abdomen sections grouped by date and village of collection.Upon DNA extraction, a quantitative polymerase chain reaction assaytargeting the conserved REPL repeat region repeats of Leishmania donovaniwas used to detect infection f Ct values were ≤ 30. For serosurvellance, all544nhabtants of the two vllages ≥2 years old were requested to provde acapillary blood sample for testing with the rK39 Rapid Diagnostic Test(RDT) on the spot, and collection on a filter paper for testing with DirectAgglutination Test (DAT) and rK39 ELISA. Demographic and VL-relatedevents were collected for each inhabitant. Overall and age group specificseroprevalences were calculated per test. A total of 727 females P.argentipes in 79 pools were analyzed. No poolswere positive for L. donovani.Blood samples were provided by 2756 (76%) inhabitants of Bishambharpurand 2773 (74%) of Rampur Jagdish. Both villages had 35 participantsreporting a VL history. RDT and DAT seroprevalence was relatively low inall age groups in both villages (<2%). ELISA seroprevalence on the otherhand was high (>8%) in all age groups in Bishambharpur, which hadcontinuous cases during and after the study period. This in contrast toRampur Jagdish which showed ELISA seroprevalence <2.5% in all agegroups, but did not have any new VL cases reported since the start of thestudy. Though no positive sandfly poolswere detected, serosurveillancewasable to detect current infections in the two villages and seems the moresensitive approach in detecting VL transmission. The rK39 ELISA seemed toreflect current transmission well, although this finding is based on highELISA seroprevalence in one village only. More frequent and targeted sandfly collection events may have resulted in increased infection detection,specifically if traps were set in households of infected inhabitants. Thiscombined approach may be useful in confirming focal transmission sitesduring the elimination phase of VL.Keywords MOLECULAR XENOMONITORING; VL DETECTION;SEROSURVEILLANCE; VISCERAL LEISHMANIASIS; VECTOR SURVEILLANCEFinancing The Bill and Melinda Gates Foundation supported the studythrough the SPEAK India consortium (OPP1183986)

O39-04: COMBINING HUMAN SEROSURVEILLANCE WITH MOLECULAR XENOMONITORING IN TWO ENDEMIC VILLAGES FOR VISCERAL LEISHMANIASIS SURVEILLANCE IN SARAN, BIHAR, INDIA

https://researchonline.lshtm.ac.uk/id/eprint/4670584/8/Carew-etal-2022-Combining-human-serosurveillance-with-molecular.pdf

O39-04: COMBINING HUMAN SEROSURVEILLANCE WITH MOLECULAR XENOMONITORING IN TWO ENDEMIC VILLAGES FOR VISCERAL LEISHMANIASIS SURVEILLANCE IN SARAN, BIHAR, INDIA

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