Serological evidence indicates widespread distribution of rickettsioses in Myanmar

Elders, Philip N D; Swe, Myo Maung Maung; Phyo, Aung Pyae; McLean, Alistair R. D.; Lin, Htet Naing; Soe, Kyaw; Htay, Wei Yan Aung; Tanganuchitcharnchai, Ampai; Hla, Thel K.; Tun, Ni Ni; Nwe, Thin Thin; Moe, Myat Myat; Thein, Win May; Zaw, Ni Ni; Kyaw, Wai Mon; Linn, Htun; Htwe, Yin Yin; Smithuis, Frank; Blacksell, Stuart D.; Ashley, Elizabeth A.

doi:10.1016/j.ijid.2020.12.013

Cited by 6 publications

(2 citation statements)

References 49 publications

(61 reference statements)

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“…Orientia tsutsugamushi has been detected in small mammal species across Southeast Asia (reviewed in [ 40 ]), and detection was usually based on bacteria isolation or serology [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. However, more recent efforts focused on PCR assays targeting the TSA47 gene for O. tsutsugamushi detection as they are more sensitive and the products can be sequenced to provide genetic information [ 49 , 50 , 51 , 52 ].…”

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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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%

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

et al. 2023

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“…Diagnosis of these pathogens relies on molecular techniques such as PCR-based amplification to demonstrate the presence of the infectious agent, as well as serological methods as a surrogate including enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays (IFA) [ 23 ]. Serological investigations allow epidemiologists to investigate the history of rickettsial exposure and estimation of seroprevalence by detecting the occurrence of preexisting levels of antibodies in a population [ 24 – 26 ]. IFA detection of IgM and/or IgG is recognized as a gold standard for rickettsial serological diagnosis, particularly for STG, however there remains uncertainty as to the most suitable diagnostic cut-off for each geographic location [ 23 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

Risk factors analysis for neglected human rickettsioses in rural communities in Nan province, Thailand: A community-based observational study along a landscape gradient

et al. 2022

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In this study, we estimated exposure for Scrub typhus (STG), Typhus (TG) and Spotted fever groups (SFG) rickettsia using serology at a fine scale (a whole sub-district administration level) of local communities in Nan Province, Thailand. Geographical characteristics of the sub-district were divided into two landscape types: lowland agricultural area in an urbanized setting (lowland-urbanized area) and upland agricultural area located close to a protected area of National Park (upland-forested area). This provided an ideal contrast between the two landscapes with low and high levels of human-altered habitats to study in differences in disease ecology. In total, 824 serum samples of participants residing in the eight villages were tested by screening IgG ELISA, and subsequently confirmed by the gold standard IgG Immunofluorescent Assay (IFA). STG and TG IgG positivity were highest with seroprevalence of 9.8% and 9.0%, respectively; whereas SFG positivity was lower at 6.9%. Inhabitants from the villages located in upland-forested area demonstrated significantly higher STG exposure, compared to those villages in the lowland-urbanized area (chi-square = 51.97, p < 0.0001). In contrast, TG exposure was significantly higher in those villagers living in lowland-urbanized area (chi-square = 28.26, p < 0.0001). In addition to the effect of landscape types, generalized linear model (GLM) analysis identified socio-demographic parameters, i.e., gender, occupation, age, educational level, domestic animal ownership (dog, cattle and poultry) as influential factors to explain the level of rickettsial exposure (antibody titers) in the communities. Our findings raise the public health awareness of rickettsiosis as a cause of undiagnosed febrile illness in the communities.

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Molecular epidemiological study of Scrub Typhus in residence, farm and forest habitats from Yunnan Province, China

Tian

Kong

Han

et al. 2023

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The number of people suffering from scrub typhus, which is not of concern, is increasing year by year, especially in Yunnan Province, China. From June 1, 2021 to August 15, 2022, a total of 505 mammalian samples were collected from farm, forest, and residential habitats with high incidence of scrub typhus in Yunnan, China, for nPCR (nested PCR) and qPCR (quantitative real-time PCR) detection of Orientia tsutsugamushi. A total of 4 orders of murine-like animals, Rodentia (87.52%, n=442), Insectivora (10.29%, n=52), Lagomorpha (1.79%, n=9) and Scandentia (0.40%, n=2) were trapped. Comparing the qPCR infection rates in the three habitats, it was no significant difference that the infection rate of residential habitat (44.44%) and that of the farm habitat (45.05%, P>0.05), which is much larger than that of the forest habitat (3.08%) (P<0.001). Three genotypes (Karp, Kato and TA763) of O. tsutsugamushi were found from Yunnan, China in this study. We found a tendency for scrub typhus to migrate from forests to residential habitats.

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Serological evidence indicates widespread distribution of rickettsioses in Myanmar

Cited by 6 publications

References 49 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

Risk factors analysis for neglected human rickettsioses in rural communities in Nan province, Thailand: A community-based observational study along a landscape gradient

Molecular epidemiological study of Scrub Typhus in residence, farm and forest habitats from Yunnan Province, China

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