Studies on tsutsugamushi by Tullgren's funnel method : 1. Evaluation of the method and distribution of Leptotrombidium pallidum in the residential areas

内川, 公人; 熊田, 信夫; 田口, 敦史; 中塚, 龍也; 福田, 晃

doi:10.7601/mez.37.363

Cited by 7 publications

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“…Two methods were used to collect free-living chiggers: black plates [35,36] and Berlese funnels (for soil samples) [37]. Black Formica plates (10 × 30 cm) were placed on the ground for 5 min before being examined.…”

Section: Free-living Chigger Collectionmentioning

confidence: 99%

Orientia tsutsugamushi dynamics in vectors and hosts: ecology and risk factors for foci of scrub typhus transmission in northern Thailand

et al. 2021

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Background Scrub typhus is an important neglected vector-borne zoonotic disease across the Asia–Pacific region, with an expanding known distribution. The disease ecology is poorly understood, despite the large global burden of disease. The key determinants of high-risk areas of transmission to humans are unknown. Methods Small mammals and chiggers were collected over an 18-month period at three sites of differing ecological profiles with high scrub typhus transmission in Chiang Rai Province, northern Thailand. Field samples were identified and tested for Orientia tsutsugamushi by real-time PCR. The rates and dynamics of infection were recorded, and positive and negative individuals were mapped over time at the scale of single villages. Ecological analyses were performed to describe the species richness, community structure and interactions between infected and uninfected species and habitats. Generalised linear modelling (GLM) was applied to examine these interactions. Results The site with the highest rates of human infection was associated with the highest number of infected chigger pools (41%), individual chiggers (16%), proportion of the known vector species Leptotrombidium deliense (71%) and chigger index (151). Chigger species diversity was lowest (Shannon diversity index H′: 1.77) and rodent density appeared to be high. There were no consistent discrete foci of infection identified at any of the study sites. The small mammals Rattus tanezumi and Bandicota indica and the chiggers L. deliense and Walchia kritochaeta emerged as central nodes in the network analysis. In the GLM, the end of the dry season, and to a lesser extent the end of the wet season, was associated with O. tsutsugamushi-infected small mammals and chiggers. A clear positive association was seen between O. tsutsugamushi-positive chigger pools and the combination of O. tsutsugamushi-positive chigger pools and O. tsutsugamushi-positive small mammals with lowland habitats. Conclusions These findings begin to reveal some of the factors that may determine high-risk foci of scrub typhus at a fine local scale. Understanding these factors may allow practical public health interventions to reduce disease risk. Further studies are needed in areas with diverse ecology. Graphical abstract

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Section: Free-living Chigger Collectionmentioning

confidence: 99%

Orientia tsutsugamushi dynamics in vectors and hosts: ecology and risk factors for foci of scrub typhus transmission in northern Thailand

et al. 2021

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“…Samples were placed into modi ed Tullgren s funnels for separating trombiculid larval mites (Uchikawa et al, 1986). All trombiculid larval mites separated were mounted on glass slides and identi ed microscopically.…”

Section: Mmentioning

confidence: 99%

Seasonal occurrence of larval trombiculid mites by Tullgren's funnel method in Kagoshima Prefecture for three years,with a few references to morphological variations

Noda

Yamamoto

Takahashi

2013

Jap. J. Sanit. Zool.

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Seasonal occurrence of larval trombiculid mites was surveyed at two adjacent areas using Tullgren s funnel method for three years. Larval trombiculid mites were collected every month from April 2004 to March 2007 at two adjacent areas of Aira City, Kagoshima Prefecture. Twenty trombiculid species were collected from soil samples: Neotrombicula mitamurai, Eltonella ichikawai, Miyatrombicula kochiensis, Cheladonta ikaoensis, Doloisia uchikawai, Helenicula miyagawai, Mackiena todai, Neoschoengastia shiraii, Schoutedenichia nagasakiensis, Walchia koshikiensis, W. ogatai and Gahrliepia saduski.Almost all species were collected in February and March, and only seven species were collected in June and July. L. scutellare was the most abundant in number, followed by L. fuji. erefore, L. scutellare and L. fuji seemed to be the dominant species in the survey areas. e morphological variation of C. ikaoensis was also observed. e scutum of C. ikaoensis was very wide, especially PW much wider than AW, and variable in the number of rst post humeral row of dorsal setae.

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“…Strains LP-1, LP-2, and LX-1, were newly isolated in this study. In these cases, a total of 1,075 unfed trombiculid mite larvae were collected from soil of several areas in Niigata Prefecture by Tullgren's funnel method (32), and the larvae were grouped into 435 of L. pallidum and 640 of the other species of trombiculid mite (the latter group consisted of many larvae of Leptotrombidium intermedium and some of other species). Then, each pool consisting of 10 to 160 mites was homogenized with a mortar in a small amount of Eagle's minimum essential medium (MEM) ( pair used was as follows: forward primer A 5'-AAAT-TATGTTAATTGCTAGTGCAATGTCTG-3' corresponding to the sequence from 9 to 38 base pairs (bp) downstream from the start codon of the 56-kDa pro-tein gene of Gilliam strain (16), and reverse primer B 5'-CTAGAAG'IvIATAGCGTACACCTGCACTTGC-3' corresponding to nucleotides from 1,538 to 1,567 by of the same gene.…”

mentioning

confidence: 99%

“…Strains LP-1, LP-2, and LX-1, were newly isolated in this study. In these cases, a total of 1,075 unfed trombiculid mite larvae were collected from soil of several areas in Niigata Prefecture by Tullgren's funnel method (32), and the larvae were grouped into 435 of L. pallidum and 640 of the other species of trombiculid mite (the latter group consisted of many larvae of Leptotrombidium intermedium and some of other species). Then, each pool consisting of 10 to 160 mites was homogenized with a mortar in a small amount of Eagle's minimum essential medium (MEM) ( ethanol precipitation, resuspended in 50111 of 10 mM Tris (p1-1 8.0)-0.1 mM EDTA, and used as the template for PCR.…”

mentioning

confidence: 99%

Demonstration of Antigenic and Genotypic Variation in Orientia tsutsugamushi Which Were Isolated in Japan, and Their Classification into Type and Subtype

Ohashi

Koyama

Urakami

et al. 1996

Microbiology and Immunology

106

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A total of 40 strains of Orientia tsutsugamushi (34 isolates from patients and trombiculid mites in Japan, and 6 prototype strains of antigenic variants) were examined for classification based on the reactivities with type-specific monoclonal antibodies in indirect immunofluorescence tests, and on the restriction fragment length polymorphism of a polymerase chain reaction (PCR)-amplified 56-kilodalton type-specific antigenic protein gene. By these methods, several antigenic and genotypic variants were found among the strains, and these variants were classified into types and further into subtypes. These results suggest that there are many variants in O. tsutsugamushi, and the methods used here seem to be useful for the systematic classification of the numerous variants. A strain which may be a new type distinguishable from those identified previously was also found in this study. Furthermore, variety in the degree of pathogenicity in mice related to type and/or subtype classification were observed.

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Studies on tsutsugamushi by Tullgren's funnel method : 1. Evaluation of the method and distribution of Leptotrombidium pallidum in the residential areas

Cited by 7 publications

References 0 publications

Orientia tsutsugamushi dynamics in vectors and hosts: ecology and risk factors for foci of scrub typhus transmission in northern Thailand

Orientia tsutsugamushi dynamics in vectors and hosts: ecology and risk factors for foci of scrub typhus transmission in northern Thailand

Seasonal occurrence of larval trombiculid mites by Tullgren's funnel method in Kagoshima Prefecture for three years,with a few references to morphological variations

Demonstration of Antigenic and Genotypic Variation in Orientia tsutsugamushi Which Were Isolated in Japan, and Their Classification into Type and Subtype

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