T Sochantha

Publications (2)5.19 Total impact

• Article: Complex population history of two Anopheles dirus mosquito species in Southeast Asia suggests the influence of Pleistocene climate change rather than human-mediated effects.

  S M O'Loughlin, T Okabayashi, M Honda, Y Kitazoe, H Kishino, P Somboon, T Sochantha, S Nambanya, P K Saikia, V Dev, C Walton
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  ABSTRACT: Anopheles dirus and Anopheles baimaii are closely related species which feed on primates, particularly humans, and transmit malaria in the tropical forests of mainland Southeast Asia. Here, we report an in-depth phylogeographic picture based on 269 individuals from 21 populations from mainland Southeast Asia. Analysis of 1537 bp of mtDNA sequence revealed that the population history of A. baimaii is far more complex than previously thought. An old expansion (pre-300 kyr BP) was inferred in northern India/Bangladesh with a wave of south-eastwards expansion arriving at the Thai border (ca 135-173 kyr BP) followed by leptokurtic dispersal very recently (ca 16 kyr BP) into peninsular Thailand. The long and complex population history of these anthropophilic species suggests their expansions are not in response to the relatively recent (ca 40 kyr BP) human expansions in mainland Southeast Asia but, rather, fit well with our understanding of Pleistocene climatic change there.
  Journal of Evolutionary Biology 10/2008; 21(6):1555-69. · 3.28 Impact Factor
• Article: Molecular identification of mosquito species in the Anopheles annularis group in southern Asia.

  C Walton, P Somboon, R E Harbach, S Zhang, I Weerasinghe, S M O'Loughlin, S Phompida, T Sochantha, W Tun-Lin, B Chen, R K Butlin
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  ABSTRACT: The Anopheles annularis group of subgenus Cellia Theobald (Diptera: Culicidae) includes five currently recognized species in southern Asia: An. annularis Van der Wulp, Anopheles nivipes (Theobald) and Anopheles philippinensis Ludlow, which are widespread in the region, Anopheles pallidus Theobald, which is known in Sri Lanka, India and Myanmar, and Anopheles schueffneri Stanton, which occurs in Java and Sumatra. Identification of the four mainland species based on morphology is problematic. In view of the fact that the three widespread species are variously involved in malaria transmission in different parts of the region, we developed a species-specific polymerase chain reaction assay based on rDNA internal transcribed spacer 2 (ITS2) sequences to facilitate entomological and epidemiological studies of the four species. The method proved to be reliable when tested over a wide geographical area.
  Medical and Veterinary Entomology 04/2007; 21(1):30-5. · 1.91 Impact Factor