WHO | Dengue Fever – Chile

On February 7, 2020, the IHR National Contact Point in Chile informed the Pan-African Health Organization / World Health Organization (PAHO / WHO) about the detection of three confirmed cases of indigenous dengue reported on Easter Island. The cases were diagnosed with polymerase chain reaction (PCR) on February 6 and by microbiological characterization, the cases were identified as serotype 2 (DENV 2 PCR). The laboratory confirmation was conducted at the National Reference Laboratory of the Chilean Institute of Public Health on February 6, 2020.

These are the first confirmed cases of dengue due to DENV 2 reported on Easter Island 2020. The cases are women aged 27-49. Symptom occurrence dates were between January 27 and February 6, 2020. None of the cases recorded travel history.

In 2000 the presence of vectors, A. aegypti, was confirmed on Easter Island. The first outbreak of dengue was reported in 2002, and on DENV 1. In 2009, two indigenous DENV 4 cases were detected, and in 2016, 2017 and 2018, DENV 1 cases (33, 2 and 18 cases) were reported, U In 2019, a total of 38 dengue cases (28 indigenous DENV 1 cases, nine imported Tahiti cases (four DENV 1 cases and five DENV 2 cases) and one probable DENV 1 indigenous case) were reported on Easter Island. In 2019, no serious cases of dengue were reported.

From 2009 to early 2020, no serotypes other than DENV 1 were identified in indigenous cases.

The density of competent vectors on Easter Island could potentially contribute to the spread of disease throughout the island.

Public health response

The measures implemented by local public health authorities are as follows:

• Strengthening active and passive epidemiological surveillance, including syndrome surveillance.
• Strengthening and intensifying vector surveillance and control.
• Ensuring healthcare professionals detect early warning signs of serious illness and appropriate clinical management of dengue patients.
• Implementing a risk communication strategy for local awareness.

WHO risk assessment

Dengue fever is a fever that affects infants, young children and adults, and the symptoms range from mild fever to high fever, with headache, pain behind the eyes, muscle and joint pain and rash. It is transmitted by mosquito bites infected with one of four dengue virus serotypes.

The introduction of the DENV 2 serotype into this population, most of which already have a primary DENV 1 infection, may present a potential risk for serious dengue cases due to secondary infections.

Easter Island has a subtropical climate. The average annual temperature is 20.5 ° C with slight variations between the seasons not usually exceeding 7 ° C. The summer runs from December 21 to March 21, and January and February are the warmest months with an average maximum temperature of 28 ° C and minimum temperature of 15 ° C.

Easter Island has weekly air links with French Polynesia, where dengue outbreaks with predominantly DENV 2. In addition, due to the presence of a competent vector and, given that Easter Island is a popular tourist destination, the risk of spreading to neighboring islands and countries cannot be excluded.

Tip of WHO

In light of the rise in dengue cases and possible dengue cases in several countries and territories of the US region, especially in 2019, PAHO / WHO encourages Member States to follow the key recommendations regarding epidemic preparedness and response, case management, laboratory management, and integrated vector management (IVM) as published in and the .

There is no specific dengue treatment; however, timely case detection, recognition of any warning signs of severe dengue, and appropriate case management are key elements of care to prevent dengue deaths. Delays in seeking medical care in severe dengue cases are often associated with deaths from dengue virus.

IVM activities should be further improved to eliminate potential breeding sites, reduce vector populations and minimize individual exposure. This should also include strategies for controlling vector larvae and adults (i.e., environmental management and source reduction and chemical control measures). Vector control measures should be implemented in households, workplaces, schools and health care facilities, inter alia, to prevent vector-to-person contact.

Taken into consideration that Aedes mosquitoes, a competent vector, have greater activity throughout the day; personal protective measures are recommended, such as the use of protective clothing that minimizes exposure to the skin and repellents that can be applied to exposed skin or clothing; the use of repellents must be in strict accordance with the instructions on the label. Window and door screens and mosquito nets (impregnated or non-insecticidal) can be helpful in reducing the contact between vectors and indoors during the day or night. Community-supported source reduction measures should be initiated and vector surveillance and control implemented.

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