TY - JOUR
T1 - Identification of risk factors and mosquito vectors associated with dengue virus infection in American Samoa, 2017
AU - Sharp, Tyler M.
AU - Tufa, A. John
AU - Cotter, Caitlin J.
AU - Lozier, Matthew J.
AU - Santiago, Gilberto A.
AU - Johnson, Stephanie S.
AU - Mataia’a, Mary
AU - Waterman, Stephen H.
AU - Muñoz-Jordán, Jorge L.
AU - Paz-Bailey, Gabriela
AU - Hemme, Ryan R.
AU - Schmaedick, Mark A.
AU - Anesi, Scott
N1 - Publisher Copyright:
This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
PY - 2023/7
Y1 - 2023/7
N2 - Introduction The first outbreak of dengue in American Samoa was reported in 1911. Sporadic outbreaks have been reported since, as were outbreaks of other pathogens transmitted by Aedes species mosquitoes including Ross River, chikungunya, and Zika viruses. During an outbreak of dengue virus-type 2 (DENV-2) in 2016–2018, we conducted household-based cluster investigations to identify population-specific risk factors associated with infection and performed entomologic surveillance to determine the relative abundance of Ae. aegypti and Ae. polynesiensis. Methods and findings We contacted dengue patients who had tested positive for DENV infection and offered them as well as their household members participation in household-based cluster investigations. For those that accepted participation, we also offered participation to residents of households within a 50-meter radius of each case-patient’s home. Questionnaires were administered and serum specimens collected for testing by RT-PCR and anti-DENV IgM ELISA. Adult female mosquitoes were aspirated from inside and outside participating households and tested by RT-PCR. We analyzed characteristics associated with DENV infection in bivariate analyses. A total of 226 participants was enrolled from 91 households in 20 clusters. Median age of participants was 34 years (range: <1–94), and 56.2% were female. In total, 7 (3.2%) participants had evidence of DENV infection by IgM ELISA (n = 5) or RT-PCR (n = 2). Factors significantly associated with DENV infection were reporting a febrile illness in the past three months (prevalence ratio: 7.5 [95% confidence interval: 1.9–29.8]) and having a household septic tank (Fisher’s Exact Test, p = 0.004). Of 93 Ae. aegypti and 90 Ae. polynesiensis females collected, 90% of Ae. aegypti were collected inside homes whereas 83% of Ae. polynesiensis were collected outside homes. DENV nucleic acid was not detected in any mosquito pools. Sequencing of the DENV-2 from patient specimens identified the Cosmopolitan genotype of DENV-2 and was most closely related to virus detected in the Solomon Islands during 2016. Conclusions This investigation demonstrated that dengue is a continuing risk in American Samoa. Increased frequency of infection among residents with a septic tank suggests a need to investigate whether septic tanks serve as larval habitats for mosquito vectors of DENV in American Samoa. Future efforts should also evaluate the role of Ae. polynesiensis in DENV transmission in the wild.
AB - Introduction The first outbreak of dengue in American Samoa was reported in 1911. Sporadic outbreaks have been reported since, as were outbreaks of other pathogens transmitted by Aedes species mosquitoes including Ross River, chikungunya, and Zika viruses. During an outbreak of dengue virus-type 2 (DENV-2) in 2016–2018, we conducted household-based cluster investigations to identify population-specific risk factors associated with infection and performed entomologic surveillance to determine the relative abundance of Ae. aegypti and Ae. polynesiensis. Methods and findings We contacted dengue patients who had tested positive for DENV infection and offered them as well as their household members participation in household-based cluster investigations. For those that accepted participation, we also offered participation to residents of households within a 50-meter radius of each case-patient’s home. Questionnaires were administered and serum specimens collected for testing by RT-PCR and anti-DENV IgM ELISA. Adult female mosquitoes were aspirated from inside and outside participating households and tested by RT-PCR. We analyzed characteristics associated with DENV infection in bivariate analyses. A total of 226 participants was enrolled from 91 households in 20 clusters. Median age of participants was 34 years (range: <1–94), and 56.2% were female. In total, 7 (3.2%) participants had evidence of DENV infection by IgM ELISA (n = 5) or RT-PCR (n = 2). Factors significantly associated with DENV infection were reporting a febrile illness in the past three months (prevalence ratio: 7.5 [95% confidence interval: 1.9–29.8]) and having a household septic tank (Fisher’s Exact Test, p = 0.004). Of 93 Ae. aegypti and 90 Ae. polynesiensis females collected, 90% of Ae. aegypti were collected inside homes whereas 83% of Ae. polynesiensis were collected outside homes. DENV nucleic acid was not detected in any mosquito pools. Sequencing of the DENV-2 from patient specimens identified the Cosmopolitan genotype of DENV-2 and was most closely related to virus detected in the Solomon Islands during 2016. Conclusions This investigation demonstrated that dengue is a continuing risk in American Samoa. Increased frequency of infection among residents with a septic tank suggests a need to investigate whether septic tanks serve as larval habitats for mosquito vectors of DENV in American Samoa. Future efforts should also evaluate the role of Ae. polynesiensis in DENV transmission in the wild.
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U2 - 10.1371/journal.pgph.0001604
DO - 10.1371/journal.pgph.0001604
M3 - Article
C2 - 37418355
AN - SCOPUS:85195574096
SN - 2767-3375
VL - 3
JO - PLOS Global Public Health
JF - PLOS Global Public Health
IS - 7
M1 - e0001604
ER -