Browsing by Author "Melanie C. Melendrez"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    PublicationMetadata only
    Characterization based on the 56-Kda type-specific antigen gene of Orientia tsutsugamushi genotypes isolated from Leptotrombidium mites and the rodent host post-infection
    (2014-01-01) Ratree Takhampunya; Bousaraporn Tippayachai; Sommai Promsathaporn; Surachai Leepitakrat; Taweesak Monkanna; Anthony L. Schuster; Melanie C. Melendrez; Daniel H. Paris; Allen L. Richards; Jason H. Richardson; Armed Forces Research Institute of Medical Sciences, Thailand; Walter Reed Army Institute of Research; Mahidol University; Naval Medical Research Center
    Characterization of the 56-kDa type-specific antigen (TSA) genes of Orientia tsutsugamushi (OT) from three naturally infected, laboratory-reared mite colonies comprising three species (Leptotrombidium deliense [Ld], Leptotrombidium imphalum [Li], and Leptotrombidium chiangraiensis [Lc]) has revealed the presence of single and coexisting OT genotypes found in individual chiggers. The Karp genotype was found in all of the chiggers examined, whereas Gilliam and UT302 genotypes were only observed in combination with the Karp genotype. From analysis of these OT genotypes after transmission from chiggers to mice it was determined that with the Lc and Li mites, the OT genotype composition in the rodent spleens post-infection had not changed and therefore resembled that observed in the feeding chiggers. However, only the Karp genotype was found in rodents after feeding by Ld chiggers carrying Karp and Gilliam genotypes. The current findings reveal a complex association among the host, pathogen, and vector. Copyright © 2014 by The American Society of Tropical Medicine and Hygiene.
  • No Thumbnail Available
    PublicationMetadata only
    Hepatitis E virus is prevalent in the pig population of Lao People's Democratic Republic and evidence exists for homogeneity with Chinese Genotype 4 human isolates
    (2011-08-01) James V. Conlan; Richard G. Jarman; Khamphouth Vongxay; Piyawan Chinnawirotpisan; Melanie C. Melendrez; Stanley Fenwick; R. C.Andrew Thompson; Stuart D. Blacksell; Murdoch University; Armed Forces Research Institute of Medical Sciences, Thailand; Ministry of Agriculture and Forestry; Mahidol University; Nuffield Department of Clinical Medicine
    The objective of this study was to determine the prevalence and genotypic range of Hepatitis E virus (HEV) in the pig population of northern Lao People's Democratic Republic (PDR). We collected 181 faecal samples from indigenous-breed pigs ≤6 months of age and the faeces was stored in RNA stabilisation buffer due to cold-chain and transport limitations. Twenty-one (11.6%) pigs had detectable HEV RNA and 43.5% of village pig herds were infected. Based on a 240 base pair-nucleotide sequence flanking the junction of open reading frames 1, 2 and 3 (ORF1, ORF2 and ORF3) the isolates were phylogenetically classified within genotype 4. Phylogenetic analyses revealed distinct genetic groupings of the Lao HEV isolates and two groups clustered with human and pig HEV isolates from China. This was the first study to demonstrate genotype 4 HEV in Lao PDR and indicates pigs are a potential reservoir for human HEV infection. © 2011 Elsevier B.V.