Screening and genotyping of Orientia tsutsugamushi from field-collected on-host chiggers (Acari: Prostigmata) recovered from a positive scrub typhus locality in Kelantan, Malaysia

Ernieenor, F C L; NorJaiza, M J; Fadillah, Arafah; Canedy, J; Ahamad, Mariana

doi:10.1007/s10493-021-00609-3

Cited by 4 publications

(4 citation statements)

References 48 publications

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“…A recent study reported the detection of O. tsutsugamushi in chiggers parasitizing R. rattus and Tupaia sp. in Malaysia, albeit from a different state, Kelantan [ 63 ]. The animal hosts were trapped in areas near the house of a scrub typhus patient, surrounded by mixed ecologies such as shrubs, coconut, fruit and sugar cane orchards.…”

Section: Discussionmentioning

confidence: 99%

“…The animal hosts were trapped in areas near the house of a scrub typhus patient, surrounded by mixed ecologies such as shrubs, coconut, fruit and sugar cane orchards. The study also reported that two of sixteen pools of Leptotrombidium deliense mites (12.5%) tested positive for O. tsutsugamushi [ 63 ]. Chaisiri et al [ 54 ] reported that O. tsutsugamushi -infected rodents in Thailand were also obtained from similar ecotypes such as forested and reforestation areas, fallows, cassava plantations and rice fields.…”

Section: Discussionmentioning

confidence: 99%

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Molecular Surveillance for Vector-Borne Bacteria in Rodents and Tree Shrews of Peninsular Malaysia Oil Palm Plantations

et al. 2023

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Many human clinical cases attributed to vector-borne pathogens are underreported in Malaysia, especially in rural localities where healthcare infrastructures are lacking. Here, 217 small mammals, consisting of rodents and tree shrews, were trapped in oil palm plantations in the Peninsular Malaysia states of Johor and Perak. Species identification was performed using morphological and DNA barcoding analyses, and 203 small mammals were included in the detection of selected vector-borne bacteria. The DNA extracted from the spleens was examined for Orientia tsutsugamushi, Borrelia spp., Bartonella spp. and Rickettsia spp. using established PCR assays. The small mammals collected in this study included Rattus tanezumi R3 mitotype (n = 113), Rattus argentiventer (n = 24), Rattus tiomanicus (n = 22), Rattus exulans (n = 17), Rattus tanezumi sensu stricto (n = 1) and Tupaia glis (n = 40). Orientia tsutsugamushi, Borrelia spp. and Bartonella phoceensis were detected in the small mammals with the respective detection rates of 12.3%, 5.9% and 4.9%. Rickettsia spp., however, was not detected. This study encountered the presence of both Lyme disease and relapsing fever-related borreliae in small mammals collected from the oil palm plantation study sites. All three microorganisms (Orientia tsutsugamushi, Borrelia spp. and Bartonella phoceensis) were detected in the R. tanezumi R3 mitotype, suggesting that the species is a competent host for multiple microorganisms. Further investigations are warranted to elucidate the relationships between the ectoparasites, the small mammals and the respective pathogens.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Molecular Surveillance for Vector-Borne Bacteria in Rodents and Tree Shrews of Peninsular Malaysia Oil Palm Plantations

et al. 2023

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“…In the last 10 years, only four studies have investigated scrub typhus seroprevalence or clinical cases in Malaysia, with a mean seroprevalence of 17.9% reported for the Orang Asli communities (asymptomatic individuals) across Peninsular Malaysia in 2013 [ 20 ]. A more recent febrile illness study in Sabah, East Malaysia, diagnosed scrub typhus in 27% of hospitalised patients [ 42 ]; also, a single hospitalised case was reported from Kelantan (northeast Peninsular Malaysia) in 2021, with subsequent identification of Orientia -positive L. deliense in the vicinity of the patient’s residence [ 43 ]. Earlier this year, a tertiary hospital study demonstrated a scrub typhus diagnosis in 8% (11% of those with confirmed aetiology) of febrile patients in Teluk Intan, which is only ~40 km south of our field site in Perak [ 44 ].…”

Section: Discussionmentioning

confidence: 99%

Habitat and Season Drive Chigger Mite Diversity and Abundance on Small Mammals in Peninsular Malaysia

et al. 2022

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Chigger mites are vectors of the bacterial disease scrub typhus, caused by Orientia spp. The bacterium is vertically transmitted in the vector and horizontally transmitted to terrestrial vertebrates (primarily wild small mammals), with humans as incidental hosts. Previous studies have shown that the size of the chigger populations is correlated with the density of small mammals in scrub typhus-endemic regions. Here, we explore interactions between the small mammals and chiggers in two oil palm plantations located in the Perak and Johor states of Peninsular Malaysia. The location in Perak also contained an aboriginal (Orang Asli) settlement. A ~5% sub-sample from 40,736 chigger specimens was identified from five species of small mammals (n = 217), revealing 14 chigger species, including two new records for Malaysia. The abundance and species richness of chiggers were significantly affected by habitat type (highest in forest border), state (highest in Perak), and season (highest in dry). The overall prevalence of Orientia tsutsugamushi DNA in small-mammal tissues was 11.7% and was not significantly affected by host or habitat characteristics, but in Johor, was positively associated with infestation by Leptotrombidium arenicola. These findings highlight the risk of contracting scrub typhus in oil palm plantations and associated human settlements.

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“…Orientia tsutsugamushi (Ot) is a Gram-negative obligate intracellular bacteria belonging to the family Rickettsiaceae, related to the genus Rickettsia (1). Scrub typhus is a mite-borne disease caused by Ot, with small mammals, especially rodents, serving as hosts and possibly reservoirs (2)(3)(4). Patients are infected through the bite of infected larval stage trombiculid mites (5).…”

Section: Introductionmentioning

confidence: 99%

Molecular diagnosis and genotyping of Orientia tsutsugamushi in Maesot and Chiangrai, Thailand

et al. 2023

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IntroductionScrub typhus is a neglected tropical disease with an estimated 1 million cases annually. The Asia-Pacific region is an endemic area for scrub typhus, especially in Thailand.MethodsBetween June 2018 and December 2019, 31 patients with acute undifferentiated febrile illness (AUFI) were recruited for clinical trials and tested positive by a scrub typhus IgM RDT.ResultsOf the 17 buffy coat patient samples tested by 47kDa real-time PCR and 56kDa type-specific antigen (TSA) nested PCR, 94% (16/17) were positive, and of the 11 patients that presented with eschar lesions, 100% (11/11) of the eschar samples were confirmed positive. Genetic analysis of the 560 bp partial 56-kDa TSA gene demonstrated that most Orientia tsutsugamushi (Ot) infections were with Karp, Gilliam, Taiwan, P23, and CM606-like strains.DiscussionThis is the second occasion that the CM606-like and P23-like strains were reported in northern Thailand (first reported in 2011 and 2013, respectively). This study demonstrates that 1) the eschar remains the most reliable biological sample for PCR diagnosis of scrub typhus and 2) Northwestern Thailand has significant diversity of Ot strains, which underlines the requirement for ongoing surveillance to increase our understanding of Ot diversity to ensure accurate diagnostics and treatment.

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Screening and genotyping of Orientia tsutsugamushi from field-collected on-host chiggers (Acari: Prostigmata) recovered from a positive scrub typhus locality in Kelantan, Malaysia

Cited by 4 publications

References 48 publications

Molecular Surveillance for Vector-Borne Bacteria in Rodents and Tree Shrews of Peninsular Malaysia Oil Palm Plantations

Molecular Surveillance for Vector-Borne Bacteria in Rodents and Tree Shrews of Peninsular Malaysia Oil Palm Plantations

Habitat and Season Drive Chigger Mite Diversity and Abundance on Small Mammals in Peninsular Malaysia

Molecular diagnosis and genotyping of Orientia tsutsugamushi in Maesot and Chiangrai, Thailand

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