The National Public Health Organization (EODY) informs and warns of an increased risk of dengue transmission to people who travel, visit or reside in foreign countries where the disease is endemic and recommends specific preventive measures.

Dengue fever and Chikungunya and Zika diseases are caused by viruses that are transmitted to humans through the bite of infected mosquitoes of the genus Aedes (mainly Aedes aegypti but also secondarily Aedes albopictus). Mosquitoes become infected when they bite people who are already infected with the virus.

Dengue is the most important mosquito-borne viral disease worldwide, with tens of millions of cases and tens of thousands of deaths annually.

It is endemic to more than 100 tropical and subtropical countries, in urban and semi-urban areas, in the Americas, the Caribbean, Asia, Africa and the Western Pacific.

Globally, a dramatic increase in Dengue fever cases has been recorded in the last two years, with > 5 million cases already recorded by 2024, raising an alarm in the global public health community.

In Europe, dengue is the second most common cause of fever (after malaria) in travelers returning from tropical-subtropical countries. In addition, in recent years, in other southern European countries (mainly France and Italy) there have been consecutive incidents of domestic transmission of Dengue fever and Chikungunya, with Aedes albopictus mosquitoes infected by infectious travelers.

In fact, in the last two years, a particularly increased number of domestic Dengue cases were recorded in France and Italy.

In our country, in recent years only imported cases of these diseases have been recorded, in a limited number, in travelers who had come from endemic countries abroad. The Aedes aegypti mosquito, which is the main transmitter of these viruses worldwide, is not established in Greece. However, as the “Asian tiger mosquito” (Aedes albopictus), which is a secondary transmitter, has also been established in our country, there is a risk of introducing these viruses through travelers (imported cases) and then of their local domestic transmission.

With the aim of preventing the local transmission of these viruses in our country, after the registration of each imported case, emergency response actions are implemented by the national, regional and local public health authorities, based on the relevant Circular of the Ministry of Health.

These actions include immediate and thorough investigation of the case, entomological and environmental investigation, risk assessment for local transmission, and – accordingly – emergency spraying or information actions by the competent local authorities in areas where the patient lived and / or visited, while he was contagious.

Regarding Dengue Fever, the clinical spectrum of the disease varies from a mild, non-specific febrile syndrome (with possible accompanying symptoms: headache, myalgias, arthralgias, rash, nausea, vomiting) to severe disease in about 5% of patients (with hemorrhagic events or even circulatory shock), which can even be fatal.

It is pointed out that, to a large extent, infection with these viruses is asymptomatic, that is, people who are infected may not show any symptoms of the disease (in Dengue up to 75 – 80% of infections may be asymptomatic). However, those infected – even asymptomatic ones – can transmit the viruses to mosquitoes that will bite them during the “contagious period” (lasting about 10 days).

Therefore, based on the above and with the aim of both protecting the health of travelers and protecting public health, EODY recommends:

People traveling to (or residing in) foreign countries where dengue fever and/or Chikungunya or Zika diseases are endemic should take scrupulous personal protection against mosquitoes:

– throughout their journey in the endemic country/region, and

– at least for three (3) weeks after their return/arrival in Greece (regardless of the presence or absence of symptoms, i.e. even if they have not become ill, because they may have an asymptomatic infection but still be “contagious” and infect the mosquitoes that will bite them).

These measures include the use of approved body (on the skin and on clothing) and environmental repellents, always in accordance with the instructions for use. These can be screens, mosquito nets, air conditioners and fans. It is also recommended to wear long clothes that cover as much of the body as possible These measures should be taken throughout the day, as these mosquitoes bite mainly during the day, with more activity in the morning and late afternoon /afternoon to dusk.

If these people experience suspicious symptoms (e.g. fever, headache, myalgias, arthralgias, rash) during the trip or after their return, they should immediately seek medical advice.

You can find the geographic distribution of Dengue, Chikungunya and Zika on the CDC, ECDC and WHO websites:

For Dengue: Countries at risk https://www.cdc.gov/dengue/areaswithrisk/around-the-world.html (list of countries and map) and https://www.ecdc.europa.eu/en/dengue -monthly (current traffic- map).

For Chikungunya: Countries at risk https://www.cdc.gov/chikungunya/geo/index.html (list of countries and map) and https://www.ecdc.europa.eu/en/chikungunya-monthly (current traffic-map).

For Zika: Countries with current or past Zika circulation: https://wwwnc.cdc.gov/travel/page/zika-travel-information (list of countries and map) and https://www.who.int/publications/ m/item/zika-epidemiology-update—february-2022 (list of countries and map).

It is reminded that travelers must be informed in time about all diseases endemic in the countries they travel to and take all recommended measures, depending on the diseases endemic (e.g. preventive treatment – “chemoprophylaxis” – for malaria, vaccinations, safe sexual practices during the trip but also after their return – for a period of time – from countries with transmission/circulation of the Zika virus, etc.).