Outbreak of Dengue Virus Type 2 — American Samoa, November 2016–October 2018

Cotter, Caitlin; Tufa, Aifili John; Johnson, Stephanie T.; Mataia, Mary Aseta; Sciulli, Rebecca; Ryff, Kyle; Hancock, W. Thane; Whelen, Christian; Sharp, Tyler M.; Anesi, Magele Scott

doi:10.15585/mmwr.mm6747a5

Cited by 13 publications

(22 citation statements)

References 9 publications

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“…From 2005 to 2015, annual rainfall ranged from 297 to 381 cm and average temperature was between 27.3-28.5 °C [1]. The wet tropical environment and resulting high density of mosquitoes [19] leads to high risk of vector-borne diseases; dengue seroprevalence was over 95% in 2010 [20] and there are frequent outbreaks of arboviral diseases [21,22]. The population, estimated at 61,181 in 2014 [1] declined between 2000 and 2010 at an estimated annual rate of − 3.1%.…”

Section: Study Locationmentioning

confidence: 99%

Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014

et al. 2020

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Background: Prevalence of lymphatic filariasis (LF) antigen in American Samoa was 16.5% in 1999. Seven rounds of mass drug administration (MDA) programmes between 2000 and 2006 reduced antigen prevalence to 2.3%. The most efficient methods of surveillance after MDA are not clear, but testing specific at-risk groups such as adults may provide earlier warning of resurgence. The role of migration from LF endemic countries in maintaining transmission also needs investigation. Few studies have investigated knowledge about LF and how that relates to infection risk. This study aims to investigate associations between socio-demographics, population mobility, disease knowledge and LF infection risk. Methods: In 2014, we surveyed 670 adults aged 16-68 years (62% female) at two worksites in American Samoa. Sera were tested for LF antigen and antibodies (Bm14 and Wb123) by rapid test and/or ELISA. Multivariate logistic regression was used to assess association between seromarkers and demographic factors, household socioeconomic status (SES), residence, travel history, and knowledge of LF. Results: Overall, 1.8% of participants were positive for antigen, 11.8% for Bm14, 11.3% for Wb123 and 17.3% for at least one antibody. Recent travel outside American Samoa was not associated with positivity for any seromarker. Men had higher seroprevalence than women for all outcomes (any antibody: adjusted odds ratio (aOR) = 3.49 (95% CI: 2.21-5.49). Those aged over 35 years (compared to 15-24 years) had higher prevalence of Bm14 antibody (aOR = 3.75, 3.76 and 4.17 for ages 35-44, 45-54 and ≥ 55 years, respectively, P < 0.05). Lower SES was associated with seropositivity (antigen: aOR = 2.89, 95% CI: 1.09-7.69; either antibody: aOR = 1.51, 95% CI: 1.12-2.05). Those who knew that mosquitoes transmitted LF had lower Wb123 antibody prevalence (aOR = 0.55, 95% CI: 0.32-0.95). Conclusions: Opportunistic sampling of adults at worksites provided an efficient and representative way to assess prevalence and risk factors for LF in American Samoa and in hindsight, foreshadowed the resurgence of transmission. Risk of LF infection, detected by one or more serological markers, was not related to recent travel history, but was strongly associated with male gender, older age, lower SES, and lack of knowledge about mosquito transmission. These results could guide future efforts to increase MDA participation.

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Section: Study Locationmentioning

confidence: 99%

Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014

et al. 2020

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“…There was seven reported outbreaks in PNG [8,13–18]; six in each of Solomon Islands, [19–25] French Polynesia, [25–30] and FSM [31–36]; three in each of American Samoa[37–39] and Marshall Island[40–42]; two from Fiji [43,44] and Guam [45,46] and one in each of Kiribati, [47] Tuvalu, [48] New Caledonia, [30] and Wallis and Futuna [30]. The aetiological agents responsible for the outbreaks were dengue virus ( n = 7), [25,19,23,26,34,39,41] influenza virus ( n = 5), [16,30,31] chikungunya virus ( n = 3), [17,28,29] Hepatitis A causing Hepatovirus ( n = 3), [35,44,40] Shigella spp . ( n = 3), [13,16,38] Vibrio cholerae ( n = 2), [18,15,14,46] mumps virus ( n = 2), [32,45] Rotavirus ( n = 2), [21,47] Zika virus ( n = 2), [27,37] measles Rubeola virus ( n = 1), [33] Mumps, circulating vaccine‐derived poliovirus type 1 ( n = 1), [8] and Rickettsia parasite causing scrub typhus ( n = 1) [20].…”

Section: Resultsmentioning

confidence: 99%

“…For 15 reports, the first author was a staff member at a national institution including ministries of health, national laboratories and universities [8,13,17,18,25,22,26–29,35,34,42,44,47]. Of international first authors, nine were from the United States Centers for Disease Control and Prevention [33,32,39,37,38,40,41,46,45]; seven were staff of WHO or the Pacific Community (the two main technical agencies providing outbreak‐related support to PICTs) [15,16,14,24,23,31,36]; five were academics from non‐PICT countries [19,21,20,43,48]; and one was from the French Government, which has responsibility for French Pacific territories [30].…”

Section: Resultsmentioning

confidence: 99%

“…Of these, 22 reports were made by clinicians (doctors and nurses) who signalled an outbreak based on their clinical judgement or after noticing temporospatial clustering of cases, [30,33,46,45,38,23,16,31,36,20,44,25,22,17,13,34,35,42,43,28] and eight were detected by laboratories. [24,26,29,32,39,37,40,41]. For six (15%) papers outbreak, alerts were raised by syndromic surveillance systems, [8,19,21,27,47,48] and two (5%) came from ad hoc notification from the community [14,15,18].…”

Section: Resultsmentioning

confidence: 99%

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Surveillance strategies for the detection of disease outbreaks in the Pacific islands: meta‐analysis of published literature, 2010–2019

Craig

Kaldor

Schierhout

et al. 2020

Tropical Med Int Health

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Objective Due to their tropical location, development status and the limited capacity of health systems, Pacific island counties and territories are particularly susceptible to infectious disease outbreaks; but evidence as to the optimal way in which outbreaks are detected is scarce. In this review, we synthesise evidence from literature about how outbreaks are detected in Pacific island countries and territories and critique factors identified as inhibiting surveillance practice. Method For this systematic review, we searched electronic databases Embase, Global Health, MEDLINE and MEDLINE Epub from 1 January 2010 and 31 March 2019 for reports describing infectious disease outbreaks occurring in the Pacific islands. Reports were included if they reported the method by which an outbreak was detected or the time between an outbreak’s onset and its detection. We extracted information about the report type and authors, the outbreak and its method/s of detection, and pertinent issues inhibiting surveillance practice. Results Of 860 articles identified, 37 reports describing 39 outbreaks met the inclusion criteria. Most outbreaks (n = 30) were identified through formal event‐based surveillance; six through syndromic surveillance; and two by ad hoc notification from the community. Barriers to early outbreak detection included population isolation; lack of resources and infrastructure to support surveillance implementation and signal investigation; and broader health system factors such as preparedness planning and availability of laboratory services. Conclusion Most surveillance‐related gain in the Pacific islands may be made through building formal event‐based surveillance systems and streamlining reporting processes to facilitate outbreak notification. This observation is pertinent given the focus on establishing and expanding syndromic surveillance approaches for outbreak detection in the islands over the last decade.

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“…With the exception of dengue in American Samoa, which reported a dengue outbreak during 2016-2018, chikungunya and dengue also generally followed the expected seasonality of mosquito-borne diseases in the northern hemisphere, with an increased number of cases during the warm summer months. 28,29 American Samoa and Puerto Rico had the highest number of dengue and Zika virus disease cases, respectively, and almost all cases of the three arboviral diseases in the territories were the result of local mosquito-borne transmission. With the exception of a small number of Zika virus disease cases (n = 15), the remainder of all chikungunya, dengue, and Zika virus disease cases reported by U.S. states occurred among travelers to areas with active virus transmission.…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of Dengue, Chikungunya, and Zika Virus Disease in U.S. States and Territories, 2017

Adams

Martin

Lindsey

et al. 2019

The American Journal of Tropical Medicine and Hygiene

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Dengue, chikungunya, and Zika viruses, primarily transmitted by Aedes species mosquitoes, have caused large outbreaks in the Americas, leading to travel-associated cases and local mosquito-borne transmission in the United States. We describe the epidemiology of dengue, chikungunya, and noncongenital Zika virus disease cases reported from U.S. states and territories in 2017, including 971 dengue cases, 195 chikungunya cases, and 1,118 Zika virus disease cases. Cases of all three diseases reported from the territories were reported as resulting from local mosquito-borne transmission. Cases reported from the states were primarily among travelers, with only seven locally acquired mosquitotransmitted Zika virus disease cases reported from Texas (n = 5) and Florida (n = 2). In the territories, most dengue cases (n = 508, 98%) were reported from American Samoa, whereas the majority of chikungunya (n = 39, 100%) and Zika virus disease (n = 620, 93%) cases were reported from Puerto Rico. Temporally, the highest number of Zika virus disease cases occurred at the beginning of the year, followed by a sharp decline, mirroring decreasing case numbers across the Americas following large outbreaks in 2015 and 2016. Dengue and chikungunya cases followed a more seasonal pattern, with higher case numbers from July through September. Travelers to the United States and residents of areas with active virus transmission should be informed of both the ongoing risk from dengue, chikungunya, and Zika virus disease and personal protective measures to lower their risk of mosquito bites and to help prevent the spread of these diseases.

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Outbreak of Dengue Virus Type 2 — American Samoa, November 2016–October 2018

Cited by 13 publications

References 9 publications

Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014

Demographic, socioeconomic and disease knowledge factors, but not population mobility, associated with lymphatic filariasis infection in adult workers in American Samoa in 2014

Surveillance strategies for the detection of disease outbreaks in the Pacific islands: meta‐analysis of published literature, 2010–2019

Epidemiology of Dengue, Chikungunya, and Zika Virus Disease in U.S. States and Territories, 2017

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