著者

Caroline Wasonga Shingo Inoue James Kimotho Kouichi Morita Juliette Ongus Rosemary Sang Lillian Musila

出版者

国立感染症研究所 Japanese Journal of Infectious Diseases 編集委員会

雑誌

Japanese Journal of Infectious Diseases (ISSN:13446304)

巻号頁・発行日

vol.68, no.5, pp.410-414, 2015 (Released:2015-09-18)

参考文献数

16

被引用文献数

1 6

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Chikungunya (CHIK) is a mosquito-borne viral disease. In the 2004 CHIK outbreak in Kenya, diagnosis was delayed because of the lack of accurate diagnostics. Therefore, this study aimed to develop and evaluate an in-house IgM-capture enzyme linked immunosorbent assay (ELISA) (in-house ELISA) for the detection of chikungunya virus (CHIKV) infections. Anti-CHIKV antibodies were raised in rabbits, purified and conjugated to horseradish peroxidase. These anti-CHIKV antibodies and cell-culture derived antigen were used to develop the ELISA. To validate the in-house ELISA, 148 patient sera from the 2005 Comoros CHIK outbreak were tested with centers for disease control and prevention (CDC) IgM-capture ELISA (CDC ELISA) and focus reduction neutralization test (FRNT) as reference assays. The in-house ELISA had a sensitivity of 97.6% and specificity of 81.3% compared to the CDC ELISA and a sensitivity of 91.1% and specificity of 96.7% compared to FRNT. Furthermore, 254 clinically suspected dengue patient samples from Eastern Kenya, collected in 2013, were tested for CHIKV IgM using the in-house ELISA. Out of the 254 samples, 26 (10.2%) were IgM positive, and of these 26 samples, 17 were further analyzed by FRNT and 14 (82.4%) were positive. The in-house ELISA was able to diagnose CHIKV infection among suspected dengue cases in the 2013 outbreak.

著者

Thu Thuy Bui Meng Ling Moi Kouichi Morita Futoshi Hasebe

出版者

National Institute of Infectious Diseases, Japanese Journal of Infectious Diseases Editorial Committee

雑誌

Japanese Journal of Infectious Diseases (ISSN:13446304)

巻号頁・発行日

pp.JJID.2019.073, (Released:2019-10-31)

参考文献数

15

被引用文献数

7

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Zika is a mosquito-borne disease that is causing significant public health threats in recent years. Zika virus (ZIKV), the causative agent of this disease, is classified into two distinct genetic lineages: Asian and African lineages. While molecular nucleic acid methods have been proved useful for the diagnosis of ZIKV infection, development of assays based on one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) offers advantages including shorter incubation times, ease of handling and rapid detection. In this study, a universal LAMP primer set was developed to target conserved sequence of known ZIKV lineages. Additionally, Af7462 and As1788 primer sets were designed based on LAMP-based SNPs typing for the specific detection of African and Asian lineages. The RT-LAMP assays detected specifically African and Asian lineages, with the limit of detection range from 0.17 FFU/ml – 2.3x102 FFU/ml. As ZIKV viremia ranges between 102 to 106 PFU/ml or 103–106 copies/mL, the data indicate that the viremia range of clinical samples is within our detection range. Because of the high specificity and sensitivity and ease of use, the results suggest the utility of the assay in early clinical diagnosis applications.

著者

Allan ole Kwallah Shingo Inoue Anne Wangari Thairu-Muigai Nancy Kuttoh Kouichi Morita Matilu Mwau

出版者

国立感染症研究所 Japanese Journal of Infectious Diseases 編集委員会

雑誌

Japanese Journal of Infectious Diseases (ISSN:13446304)

巻号頁・発行日

vol.68, no.3, pp.230-234, 2015 (Released:2015-05-20)

参考文献数

22

被引用文献数

11

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Yellow fever (YF), which is caused by a mosquito-borne virus, is an important viral hemorrhagic fever endemic in equatorial Africa and South America. Yellow fever virus (YFV) is the prototype of the family Flaviviridae and genus Flavivirus. The aim of this study was to determine the seroprevalence of YFV in selected health facilities in Western Kenya during the period 2010–2012. A total of 469 serum samples from febrile patients were tested for YFV antibodies using in-house IgM-capture ELISA, in-house indirect IgG ELISA, and 50% focus reduction neutralization test (FRNT50). The present study did not identify any IgM ELISA-positive cases, indicating absence of recent YFV infection in the area. Twenty-eight samples (6%) tested positive for YFV IgG, because of either YFV vaccination or past exposure to various flaviviruses including YFV. Five cases were confirmed by FRNT50; of these, 4 were either vaccination or natural infection during the YF outbreak in 1992–1993 or another period and 1 case was confirmed as a West Nile virus infection. Domestication and routine performance of arboviral differential diagnosis will help to address the phenomenon of pyrexia of unknown origin, contribute to arboviral research in developing countries, and enhance regular surveillance.

著者

Basu D. Pandey Takeshi Nabeshima Kishor Pandey Saroj P. Rajendra Yogendra Shah Bal R. Adhikari Govinda Gupta Ishan Gautam Mya M. N. Tun Reo Uchida Mahendra Shrestha Ichiro Kurane Kouichi Morita

出版者

日本熱帯医学会

雑誌

Tropical Medicine and Health (ISSN:13488945)

巻号頁・発行日

pp.2012-17, (Released:2013-08-20)

参考文献数

28

被引用文献数

6 33

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Dengue is an emerging disease in Nepal and was first observed as an outbreak in nine lowland districts in 2006. In 2010, however, a large epidemic of dengue occurred with 4,529 suspected and 917 serologically-confirmed cases and five deaths reported in government hospitals in Nepal. The collection of demographic information was performed along with an entomological survey and clinical evaluation of the patients. A total of 280 serum samples were collected from suspected dengue patients. These samples were subjected to routine laboratory investigations and IgM-capture ELISA for dengue serological identification, and 160 acute serum samples were used for virus isolation, RT-PCR, sequencing and phylogenetic analysis. The results showed that affected patients were predominately adults, and that 10% of the cases were classified as dengue haemorrhagic fever/ dengue shock syndrome. The genetic characterization of dengue viruses isolated from patients in four major outbreak areas of Nepal suggests that the DENV-1 strain was responsible for the 2010 epidemic. Entomological studies identified Aedes aegypti in all epidemic areas. All viruses belonged to a monophyletic single clade which is phylogenetically close to Indian viruses. The dengue epidemic started in the lowlands and expanded to the highland areas. To our knowledge, this is the first dengue isolation and genetic characterization reported from Nepal.

著者

Duc Tuan Dinh Mai Thi Quynh Le Cuong Duc Vuong Futoshi Hasebe Kouichi Morita

出版者

日本熱帯医学会

雑誌

Tropical Medicine and Health (ISSN:13488945)

巻号頁・発行日

vol.39, no.1, pp.3-7, 2011 (Released:2011-03-24)

参考文献数

13

被引用文献数

22 53

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We designed a new set of primers for reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) to specifically amplify the HA gene of avian influenza viruses subtype H5N1. By testing nine H5N1 virus strains and 41 clinical samples collected in Northern Vietnam, we found that the new primers showed higher sensitivity and specificity than the previously published RT-LAMP primers and were comparable to the RT-PCR method currently recommended by WHO. These results suggest that our RT-LAMP assay may be a better choice as a diagnostic tool for current H5N1 influenza virus infection.