In Laos, Tuberculosis (TB) and drug resistant TB represent a significant public health threat. Because of the restrictive measures and the strain on health systems for COVID-19 control, the pandemic has had a negative effect on the number of TB cases (diagnosis, treatment, and follow-up), causing a drop in notifications and most certainly an increase in mortality from Mycobacterium tuberculosis. TB is also considered an emerging disease in wildlife. In South-East Asia, the disease is also threatening elephants (Elephas maxima) and sun bears (Helarctos malayanus).
Asian elephants are victims of shrinking habitat, poaching, human conflicts and diseases and are listed as Endangered on the IUCN red list. Captive elephants are employed for tourism-festival purposes, although hundreds still work in illegal logging. In Laos, owning an elephant is still a conventional practice. The constant proximity between the elephant and its mahout (someone who owns or works with an elephant) increases the chances of diseases transmissions in both directions, notably Tuberculosis. This has already been documented among keepers and elephants in zoos and sanctuaries across the world. For the diagnosis in elephants, veterinarians are required to collect trunk washes or blood samples from trained animals, with results of varying degree of sensitivity and specificity. These techniques are not applicable to untrained elephants, therefore, a diagnostic method based on non-invasively collected samples is a more suitable approach.
On April 18th, Sabrina Locatelli IRD researcher at MIVEGEC and project leader of "ELAOS - The Emergence of Tuberculosis at the Human-Elephant Interface" (funded by OHSEA - One Health in South East Asia, sponsored by Ministry of Europe and Foreign Affairs, Solidarity Fund for Innovative Projects programs (FSPI), IRD, CNRS), visited the Elephant Conservation Center (ECC) to inform the mahouts about the project and to set up the elephant and mahouts samples collection. The main objective of this project is to determine Mycobacterium tuberculosis (Mt) prevalence and antibiotic resistance among captive Asian elephants and their mahouts to better evaluate the risk of TB emergence at the human-animal interface in Laos.
Elephant fecal samples will be collected in Tongmixay district, which contains the largest remaining captive elephant populations and at the Elephant Conservation Center (ECC) (Sayaboury district) and will be sent to the Medical Biology Unit (LMI DRISA partner) of Institut Pasteur du Cambodge (IPC), Phnom Penh, for analysis. In this laboratory faecal samples from Mycobacterium tuberculosis infected sun bears (Helarctos malayanus) collected from a wildlife rescue center in Cambodia will be used as positive controls. Sputum and/or fecal samples for each mahout with suspected TB infection will be collected and sent to the National reference Laboratory for TB in Vientiane (Centre d’Infectiologie Lao Christophe Mérieux-CILM) for culture, molecular identification and drug susceptibility testing.
Ultimately, sampling the entirety of the existing 450 domesticated elephants working in Laos, is the next step. In addition, domesticated elephants in Southeast Asia regularly interact with wild elephants inhabiting nearby forests. In regions such as the Namphuy protected area in Sayaboury province, which is home to the second largest population of wild elephants in Laos, the mahouts’ practice of releasing females to get impregnated by wild males acts to maintain gene flow between wild elephants and their domestic counterparts. Because of the close interaction of domesticated elephants with humans, the risk of anthropo-zoonotic transmission increases in the domesticated population and could ultimately affect the wild population.
This project was made possible thanks to the capacity building of southern partners and advice on the development of innovative tools from the Southern Capacity Building Service, Department of Mobilisation of Research and Innovation for Development (DMOB) of IRD.
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