Dengue 2018-2024 - Centro Nazionale Sangue

Dengue is a viral infection caused by the Dengue virus (DENV), transmitted to humans through the bite of infected mosquitoes. There is no direct infection between humans, even if humans are the main host of the virus. The virus circulates in the blood of the infected person for 2-7 days, and in this period the mosquito can pick it up and transmit it to other individuals. In the Western Hemisphere the main vector is the Aedes aegypti mosquito, although cases of transmission by Aedes albopictus have been recorded. Dengue has been known for over two centuries, and is particularly present during and after the rainy season in the tropical and subtropical areas of Africa, Southeast Asia and China, India, the Middle East, Latin and Central America, Australia and several areas of the Pacific.

EpIn recent decades, the spread of dengue has grown in many tropical regions. In northern hemisphere countries, particularly in Europe, it poses a danger from a global health perspective, as it manifests itself mainly as an imported disease, the rising incidence of which is due to the increased movement of goods and people. According to the WHO, the incidence of dengue has increased 30-fold in the last 50 years. It is estimated that up to 50-100 million infections occur annually in more than 100 endemic countries, putting almost half of the world’s population at risk.

Epidemiological surveillance (update 12/12/2024)

The following information are based on the epidemiological updates provided by the European Center Disease and Control – ECDC, through the Multi-country (World) Monitoring global outbreaks, the following is represented.

Global update
Since the beginning of 2024, more than 14 million DENV cases and more than 10,000 related deaths have been reported globally. Most cases have been reported in the WHO PAHO region (over 12 million cases in 2024, 53% of which were confirmed by a lab analysis, and over 7,000 deaths).

Brazil has reported the highest number of cases (over 9.8 million), followed by Argentina, Mexico, Colombia and Paraguay.

The Americas are currently facing the largest DENV epidemic ever. As a result, there has been a substantial increase in the number of cases imported into the EU/EEA since the beginning of the year.

DENV circulation has also been reported in the WHO Eastern Mediterranean, South-East Asia and Western Pacific regions, according to reports from regional offices (Regional Office for the Eastern Mediterranean, EMRO, Regional Office for South-East Asia, SEARO, and Western Pacific Regional Office, WPRO, respectively), as well as in Africa. Specifically:

In the EMRO region, indigenous cases were first reported in Iran in June 2024; Dengue has also been reported in Afghanistan, Saudi Arabia and Pakistan.
According to the SEARO report, in Bangladesh, the total number of DENV cases and related deaths in 2024 continues to be at lower levels compared to the same period in 2023. In Nepal, 28,212 cases were reported through the early warning system. DENV has also been reported in India (Kerala and Karnataka). The monthly number of cases continued to decline in Indonesia, after peaking between March and May; over 0.6 million suspected and confirmed cases (including over 1,200 deaths) have been reported as of early October.
According to the WPRO update, generally declining trends, with weekly fluctuations, were reported from Cambodia and Laos. Similar trends have been observed in Malaysia and Singapore. In China, the number of reported cases increased between June and September. In Vietnam, an increasing number of cases were reported in October, however below the levels reported in 2023.
In Africa, according to the Africa CDC Epidemic Intelligence Report and the WHO African Region bulletin, over 100,000 DENV cases have been reported (Burkina Faso, Cameroon, Cape Verde, Central African Republic, Chad, Ivory Coast, Ethiopia, Ghana, Guinea, Kenya, Mali, Mauritius, Niger, Nigeria, Sao Tomé and Principe, Senegal, Sudan and Togo).

With reference to France oversea territories, historically, DENV is endemic in French Guiana, Guadeloupe, La Réunion, Martinique, Mayotte and Saint-Martin.

An increase in DENV cases has been reported in the Department of Guadeloupe since mid-September, after decreasing and stable trends during the summer. In the Department of Martinique, overall, there is an increasing trend in the number of cases reported with clinical symptoms of Dengue and the epidemiological situation is characterized as epidemic phase 2. The circulation of dengue continues in the Collectivity of Saint-Martin, but at lower levels (epidemic phase 1), with only sporadic cases or outbreaks without epidemiological links between them reported. In the Department of French Guiana, over 8,000 confirmed cases of DENV have been reported since the beginning of 2024 and until August 2024, with a currently stable trend.

In the Department of La Reunion since the beginning of the year and until August 2024, a total of 1,265 cases of DENV have been reported. Currently, traffic on the island is reported to be moderate.

In the Department of Mayotte, indigenous cases were reported during the summer; no new cases have been reported since the beginning of September 2024.

Europe
With reference to the European epidemiological situation, the European Center Disease and Control – ECDC has not yet declared the closure of emergencies for indigenous cases of DENV infection in the following territories:

France:
– Gard Department (Occitaine Region)

Spagna:
– Tarragona Province

Since these are areas declared endemic, the measures remain active for the overseas departments of French Guiana, Guadeloupe, La Réunion, Martinique, Mayotte and in the Collectivity of Saint-Martin.

Given the above, without prejudice to the provisions of the Ministerial Decree of 2 November 2015 relating to the exclusion criteria for travel to tropical areas, with respect to other European and non-European areas with active circulation reported by the WHO and ECDC, it is recommended to:

Strengthen surveillance measures on possible imported cases of DENV by activating anamnestic surveillance of blood donors for travel to risk areas;
For donors who have stayed in the affected areas apply a temporary suspension of 28 days starting from the return date or, alternatively, carry out the DENV NAT test on all donors;
For donors with a positive history of DENV infection (documented infection or appearance of symptoms compatible with DENV infection) apply a temporary suspension of 120 days starting from the resolution of symptoms
Raise awareness among donors to inform the competent transfusion service in the event of the appearance of symptoms compatible with DENV infection or in the event of a diagnosis of DENV infection in the 14 days following the donation (post donation information).

Testing and suspension periods may be waived if the donation is used exclusively for plasma intended for fractionation.

Italy
In Italy, since no further autochthonous cases were reported, the prevention measures implemented in the following municipalities are now suspended: Albinea (RE), Castelfidardo (AN) Cavezzo (MO), Malo (VI), Ortona (CH), Ospitaletto e Cazzago San Martino (BS), Pesaro, Fano e San Costanzo (PU), Rapolano Terme (SI), Sesto Fiorentino (FI).

The National Blood Centre will update these indications in relation to the evolution of the national and international epidemiological situation.

For the HSC prevention measures, please refer to the dedicated CNT page.

DENV Cases maps August-October 2024 — DENV case reported August-October 2024

Decrees (Italian Text)