Surveillance of potential hosts and vectors of scrub typhus in Taiwan
Abstract Background Scrub typhus is a lethal infectious disease vectored by larval trombiculid mites (i.e. chiggers) infected with Orientia tsutsugamushi (OT) and recent decades have witnessed an emergence of scrub typhus in several countries. Identification of chigger species and their vertebrate h...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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BMC
2015-12-01
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| Series: | Parasites & Vectors |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s13071-015-1221-7 |
| _version_ | 1797811898708656128 |
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| author | Chi-Chien Kuo Pei-Lung Lee Chun-Hsung Chen Hsi-Chieh Wang |
| author_facet | Chi-Chien Kuo Pei-Lung Lee Chun-Hsung Chen Hsi-Chieh Wang |
| author_sort | Chi-Chien Kuo |
| collection | DOAJ |
| description | Abstract Background Scrub typhus is a lethal infectious disease vectored by larval trombiculid mites (i.e. chiggers) infected with Orientia tsutsugamushi (OT) and recent decades have witnessed an emergence of scrub typhus in several countries. Identification of chigger species and their vertebrate hosts is fundamental for the assessment of human risks to scrub typhus under environmental changes, but intensive and extensive survey of chiggers and their hosts is still lacking in Taiwan. Methods Chiggers were collected from shrews and rodents in nine counties of Taiwan and were assayed for OT infections with nested polymerase chain reaction (PCR). PCR products were further sequenced to reveal probable OT strains. Rodents were assessed for OT exposure by immunofluorescent antibody assay. Lastly, incidence rate of scrub typhus in each county was associated with loads and prevalence of chigger infestations, seropositivity rate in rodents, and OT positivity rate in chiggers. Results Rattus losea was the most abundant (48.7 % of 1,285 individuals) and widespread (occurred in nine counties) small mammal species and hosted the majority of chiggers (76.4 % of 128,520 chiggers). Leptotrombidium deliense was the most common (64.9 % of all identified chiggers) and widespread (occurred in seven counties) chigger species but was replaced by Leptotrombidium pallidum or Leptotrombidium scutellare during the cold seasons in two counties (Matsu and Kinmen) where winter temperatures were lower than other study sites. Seropositivity rate for OT exposure in 876 assayed rodents was 43.0 % and OT positivity rate in 347 pools of chiggers was 55.9 %, with 15 OT strains identified in the 107 successfully sequenced samples. Incidence rate of scrub typhus was positively correlated with chigger loads, prevalence of chigger infestations, seropositivity rate but not OT positivity rate in chiggers. Conclusions Our study reveals R. losea as the primary host for chiggers and there exists a geographical and seasonal variation in chigger species in Taiwan. It also emphasizes the importance of recognition of chigger vectors and their vertebrate hosts for a better prediction of human risks to scrub typhus under rapid environmental changes. |
| first_indexed | 2024-03-13T07:30:37Z |
| format | Article |
| id | doaj.art-7dabb88e65e94e6187c4081770c68ae9 |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-03-13T07:30:37Z |
| publishDate | 2015-12-01 |
| publisher | BMC |
| record_format | Article |
| series | Parasites & Vectors |
| spelling | doaj.art-7dabb88e65e94e6187c4081770c68ae92023-06-04T11:08:35ZengBMCParasites & Vectors1756-33052015-12-018111110.1186/s13071-015-1221-7Surveillance of potential hosts and vectors of scrub typhus in TaiwanChi-Chien Kuo0Pei-Lung Lee1Chun-Hsung Chen2Hsi-Chieh Wang3Department of Life Science, National Taiwan Normal UniversityCenter for Research, Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and WelfareCenter for Research, Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and WelfareCenter for Research, Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and WelfareAbstract Background Scrub typhus is a lethal infectious disease vectored by larval trombiculid mites (i.e. chiggers) infected with Orientia tsutsugamushi (OT) and recent decades have witnessed an emergence of scrub typhus in several countries. Identification of chigger species and their vertebrate hosts is fundamental for the assessment of human risks to scrub typhus under environmental changes, but intensive and extensive survey of chiggers and their hosts is still lacking in Taiwan. Methods Chiggers were collected from shrews and rodents in nine counties of Taiwan and were assayed for OT infections with nested polymerase chain reaction (PCR). PCR products were further sequenced to reveal probable OT strains. Rodents were assessed for OT exposure by immunofluorescent antibody assay. Lastly, incidence rate of scrub typhus in each county was associated with loads and prevalence of chigger infestations, seropositivity rate in rodents, and OT positivity rate in chiggers. Results Rattus losea was the most abundant (48.7 % of 1,285 individuals) and widespread (occurred in nine counties) small mammal species and hosted the majority of chiggers (76.4 % of 128,520 chiggers). Leptotrombidium deliense was the most common (64.9 % of all identified chiggers) and widespread (occurred in seven counties) chigger species but was replaced by Leptotrombidium pallidum or Leptotrombidium scutellare during the cold seasons in two counties (Matsu and Kinmen) where winter temperatures were lower than other study sites. Seropositivity rate for OT exposure in 876 assayed rodents was 43.0 % and OT positivity rate in 347 pools of chiggers was 55.9 %, with 15 OT strains identified in the 107 successfully sequenced samples. Incidence rate of scrub typhus was positively correlated with chigger loads, prevalence of chigger infestations, seropositivity rate but not OT positivity rate in chiggers. Conclusions Our study reveals R. losea as the primary host for chiggers and there exists a geographical and seasonal variation in chigger species in Taiwan. It also emphasizes the importance of recognition of chigger vectors and their vertebrate hosts for a better prediction of human risks to scrub typhus under rapid environmental changes.https://doi.org/10.1186/s13071-015-1221-7HostsLeptotrombidiumOrientia tsutsugamushiRattusScrub typhusTaiwan |
| spellingShingle | Chi-Chien Kuo Pei-Lung Lee Chun-Hsung Chen Hsi-Chieh Wang Surveillance of potential hosts and vectors of scrub typhus in Taiwan Parasites & Vectors Hosts Leptotrombidium Orientia tsutsugamushi Rattus Scrub typhus Taiwan |
| title | Surveillance of potential hosts and vectors of scrub typhus in Taiwan |
| title_full | Surveillance of potential hosts and vectors of scrub typhus in Taiwan |
| title_fullStr | Surveillance of potential hosts and vectors of scrub typhus in Taiwan |
| title_full_unstemmed | Surveillance of potential hosts and vectors of scrub typhus in Taiwan |
| title_short | Surveillance of potential hosts and vectors of scrub typhus in Taiwan |
| title_sort | surveillance of potential hosts and vectors of scrub typhus in taiwan |
| topic | Hosts Leptotrombidium Orientia tsutsugamushi Rattus Scrub typhus Taiwan |
| url | https://doi.org/10.1186/s13071-015-1221-7 |
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