Molecular detection of Loxodontofilaria spp. in Asian elephants (Elephas maximus) from elephant training camps in Thailand

Saengsawang Phirabhat, Desquesnes Marc, Yangtara Sarawut, Chalermwong Piangjai, Thongtip Nikorn, Jittapalapong Sathaporn, Inpankaew Tawin. 2023. Molecular detection of Loxodontofilaria spp. in Asian elephants (Elephas maximus) from elephant training camps in Thailand. Comparative Immunology, Microbiology and Infectious Diseases, 92:101910, 8 p.

https://doi.org/10.1016/j.cimid.2022.101910

Article de revue ; Article de revue à facteur d'impact

Version publiée - Anglais
Accès réservé aux personnels Cirad
Utilisation soumise à autorisation de l'auteur ou du Cirad.
ID608521.pdf
Télécharger (2MB)

Résumé : Filarial infection is an important disease in human and animal medicine. Several ﬁlarial worms are of importance, especially nematodes in the Onchocercidae. The Asian elephant (Elephas maximus) is an endangered animal and is very important from several socio-economic and ecological aspects in Thailand. Various parasites can be found in elephants; however, data related to ﬁlarial infections in elephants is limited. The objective of this study was to detect ﬁlaria in the blood of Asian elephants in Thailand, based on a polymerase chain reaction (PCR) technique. Blood samples were collected from 208 Asian elephants and detected for ﬁlaria using PCR, targeting the region of the internal transcribed spacer 2 (ITS2), the cytochrome c oxidase subunit 1 (cox1), and the RNA polymerase II large subunit (rbp1). In total, 4.33% (9 out of 208) of the sampled elephants had Loxodontoﬁlaria spp. DNA with 100% query coverage. In addition, the obtained cox1 and rbp1 sequences matched with Loxodontoﬁlaria sp., Onchocerca sp., and Diroﬁlaria sp. There were no identiﬁed risk factors (sex, age, location, and packed cell volume) related to Loxodontoﬁlaria infection in elephants. The analyses of the phylogeny of ITS2 sequences demonstrated that the Loxodotoﬁlaria-positive sequences were closely related to Onchocerca dewittei japonica and Onchocerca dewittei dewittei with 100% query coverage. Notably, the concatenated phylogenetic trees of ITS2 and the cox1 and rbp1 genes were closely similar to Loxodontoﬁlaria sp. To describe in detail the genomic DNA of Loxodontoﬁlaria spp., other genes should be additionally studied using a more discriminatory technique, such as DNA barcoding or whole genome sequencing.

Mots-clés Agrovoc : phylogénie, Elephas maximus, écologie animale, adn, PCR, maladie de l'homme, Onchocercidae, séquence nucléotidique, Onchocerca, biologie moléculaire, maladie des animaux, facteur de risque, surveillance épidémiologique, gène