Screening for visceral leishmaniasis in humans and animals in Laos

Abstract Background Visceral leishmaniasis (VL) is a vector-borne protozoan disease with a global distribution, with higher rates of infection associated with HIV. Zoonotic species of Leishmania have also been reported infecting domestic animals. Reports of VL are increasing in Southeast Asia, with...

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Main Authors: Tamalee Roberts, Anousone Douangnouvong, Matthew T. Robinson, Koukeo Phommasone, Saykham Phaxayaseng, Valy Keoluangkhot, Khamsing Vongphayloth, Aphaphone Adsamoud, Othila Rasphone, Leeyounjera Yang, Phonelevanh Phoumin, Manivone Simmalavong, Peter Christensen, Tom Hughes, Adisone Temmerath, Alex Inthavong, Phoummavanh Inthapanya, Sivone Punyasith, Phouvong Phommachanh, Wattana Theppangna, Syseng Khounsy, Susath Vongphachanh, Stuart D. Blacksell, Paul N. Newton, Mayfong Mayxay, Elizabeth A. Ashley
Format: Article
Language:English
Published: BMC 2025-08-01
Series:Tropical Medicine and Health
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Online Access:https://doi.org/10.1186/s41182-025-00782-w
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author Tamalee Roberts
Anousone Douangnouvong
Matthew T. Robinson
Koukeo Phommasone
Saykham Phaxayaseng
Valy Keoluangkhot
Khamsing Vongphayloth
Aphaphone Adsamoud
Othila Rasphone
Leeyounjera Yang
Phonelevanh Phoumin
Manivone Simmalavong
Peter Christensen
Tom Hughes
Adisone Temmerath
Alex Inthavong
Phoummavanh Inthapanya
Sivone Punyasith
Phouvong Phommachanh
Wattana Theppangna
Syseng Khounsy
Susath Vongphachanh
Stuart D. Blacksell
Paul N. Newton
Mayfong Mayxay
Elizabeth A. Ashley
author_facet Tamalee Roberts
Anousone Douangnouvong
Matthew T. Robinson
Koukeo Phommasone
Saykham Phaxayaseng
Valy Keoluangkhot
Khamsing Vongphayloth
Aphaphone Adsamoud
Othila Rasphone
Leeyounjera Yang
Phonelevanh Phoumin
Manivone Simmalavong
Peter Christensen
Tom Hughes
Adisone Temmerath
Alex Inthavong
Phoummavanh Inthapanya
Sivone Punyasith
Phouvong Phommachanh
Wattana Theppangna
Syseng Khounsy
Susath Vongphachanh
Stuart D. Blacksell
Paul N. Newton
Mayfong Mayxay
Elizabeth A. Ashley
author_sort Tamalee Roberts
collection DOAJ
description Abstract Background Visceral leishmaniasis (VL) is a vector-borne protozoan disease with a global distribution, with higher rates of infection associated with HIV. Zoonotic species of Leishmania have also been reported infecting domestic animals. Reports of VL are increasing in Southeast Asia, with over 200 cases reported in Thailand since the first autochthonous case in 1999, and recently the first patients have been reported from Vietnam and Cambodia. However, no cases of VL have been reported from Lao PDR (Laos) and clinical awareness of the disease is limited. This study aimed to investigate whether Leishmania is circulating in Laos by screening people living with HIV, stored samples from unselected patients with fever, and ruminants taken to abattoirs. Methods People living with HIV from two specialist units in Vientiane Capital had EDTA blood taken and DNA extracted and tested for Leishmania by nested-PCR. Stored serum samples from patients presenting to Mahosot Hospital with fever and without known HIV infection, as well as serum from goats, cows and buffalo taken to abattoirs in four provinces in Laos were tested for Leishmania using the InBios Kalazar Detect Rapid Test. Results There were 1015 people living with HIV tested between 2021 and 2024 for Leishmania by nested-PCR, all of whom were negative. Of 511 human serum samples collected between 2005 and 2023, two (0.4%) tested positive by rapid test. These samples were identified as coming from the same patient, with samples taken 10 months apart. There were 5/159 (3.1%) ruminant serum samples positive by rapid test with 3/45 (6.7%) buffalo positive, 2/47 (4.3%) goat positive and 0/67 cows positive. Conclusions This study suggests Leishmania may be circulating in Laos with undetected cases. Further investigation is needed to confirm the findings, determine at-risk populations and increase clinical awareness of the disease. This study expands on the current regional knowledge on leishmaniasis and shows the need for further epidemiological studies.
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spelling doaj-art-49ffca2c71fc422fb4641e74875a266c2025-08-20T03:06:06ZengBMCTropical Medicine and Health1349-41472025-08-015311710.1186/s41182-025-00782-wScreening for visceral leishmaniasis in humans and animals in LaosTamalee Roberts0Anousone Douangnouvong1Matthew T. Robinson2Koukeo Phommasone3Saykham Phaxayaseng4Valy Keoluangkhot5Khamsing Vongphayloth6Aphaphone Adsamoud7Othila Rasphone8Leeyounjera Yang9Phonelevanh Phoumin10Manivone Simmalavong11Peter Christensen12Tom Hughes13Adisone Temmerath14Alex Inthavong15Phoummavanh Inthapanya16Sivone Punyasith17Phouvong Phommachanh18Wattana Theppangna19Syseng Khounsy20Susath Vongphachanh21Stuart D. Blacksell22Paul N. Newton23Mayfong Mayxay24Elizabeth A. Ashley25Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalHIV Unit, Setthathirath HospitalDepartment of Infectious Diseases, Mahosot HospitalInstitut Pasteur du Laos, Laboratory of Vector-Borne DiseasesLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalDepartment of Infectious Diseases, Mahosot HospitalDepartment of Infectious Diseases, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityNational Animal Health LaboratoryNational Animal Health LaboratoryMahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol UniversityMahosot HospitalCentre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of OxfordLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalLao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot HospitalAbstract Background Visceral leishmaniasis (VL) is a vector-borne protozoan disease with a global distribution, with higher rates of infection associated with HIV. Zoonotic species of Leishmania have also been reported infecting domestic animals. Reports of VL are increasing in Southeast Asia, with over 200 cases reported in Thailand since the first autochthonous case in 1999, and recently the first patients have been reported from Vietnam and Cambodia. However, no cases of VL have been reported from Lao PDR (Laos) and clinical awareness of the disease is limited. This study aimed to investigate whether Leishmania is circulating in Laos by screening people living with HIV, stored samples from unselected patients with fever, and ruminants taken to abattoirs. Methods People living with HIV from two specialist units in Vientiane Capital had EDTA blood taken and DNA extracted and tested for Leishmania by nested-PCR. Stored serum samples from patients presenting to Mahosot Hospital with fever and without known HIV infection, as well as serum from goats, cows and buffalo taken to abattoirs in four provinces in Laos were tested for Leishmania using the InBios Kalazar Detect Rapid Test. Results There were 1015 people living with HIV tested between 2021 and 2024 for Leishmania by nested-PCR, all of whom were negative. Of 511 human serum samples collected between 2005 and 2023, two (0.4%) tested positive by rapid test. These samples were identified as coming from the same patient, with samples taken 10 months apart. There were 5/159 (3.1%) ruminant serum samples positive by rapid test with 3/45 (6.7%) buffalo positive, 2/47 (4.3%) goat positive and 0/67 cows positive. Conclusions This study suggests Leishmania may be circulating in Laos with undetected cases. Further investigation is needed to confirm the findings, determine at-risk populations and increase clinical awareness of the disease. This study expands on the current regional knowledge on leishmaniasis and shows the need for further epidemiological studies.https://doi.org/10.1186/s41182-025-00782-wVisceral leishmaniasisLeishmaniaLao PDRRuminantsZoonosis
spellingShingle Tamalee Roberts
Anousone Douangnouvong
Matthew T. Robinson
Koukeo Phommasone
Saykham Phaxayaseng
Valy Keoluangkhot
Khamsing Vongphayloth
Aphaphone Adsamoud
Othila Rasphone
Leeyounjera Yang
Phonelevanh Phoumin
Manivone Simmalavong
Peter Christensen
Tom Hughes
Adisone Temmerath
Alex Inthavong
Phoummavanh Inthapanya
Sivone Punyasith
Phouvong Phommachanh
Wattana Theppangna
Syseng Khounsy
Susath Vongphachanh
Stuart D. Blacksell
Paul N. Newton
Mayfong Mayxay
Elizabeth A. Ashley
Screening for visceral leishmaniasis in humans and animals in Laos
Tropical Medicine and Health
Visceral leishmaniasis
Leishmania
Lao PDR
Ruminants
Zoonosis
title Screening for visceral leishmaniasis in humans and animals in Laos
title_full Screening for visceral leishmaniasis in humans and animals in Laos
title_fullStr Screening for visceral leishmaniasis in humans and animals in Laos
title_full_unstemmed Screening for visceral leishmaniasis in humans and animals in Laos
title_short Screening for visceral leishmaniasis in humans and animals in Laos
title_sort screening for visceral leishmaniasis in humans and animals in laos
topic Visceral leishmaniasis
Leishmania
Lao PDR
Ruminants
Zoonosis
url https://doi.org/10.1186/s41182-025-00782-w
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