Dengue cases recorded in the American region since the beginning of this year have exceeded 3 million, reports the World Health Organization.
Approximately 80% of those infected by the virus carried by mosquitoes are concentrated in Brazil. In 2023 – the WHO recalls – the Americas region reported the highest number of dengue cases since they were counted, with 4.5 million infected, including 7,665 serious cases and 2,363 deaths.
In 2024 the region records a new record: over 3 million cases as of March 25. The majority were reported in Brazil (81% of cases), followed by Paraguay (6%), Argentina (3.4%), Peru (2.6%) and Colombia (2.2%). Paho, the Pan American Health Organization, is working together with the ministries of health of various countries in two main directions: mosquito control and death prevention.
Emergency in Puerto Rico
Puerto Rico’s government has declared a dengue epidemic after a spike in cases of the mosquito-borne infection hit the Caribbean island, an unincorporated US territory. From the beginning of 2024 to March 10, according to the most recent data provided by the local Department of Health, 549 cases of Dengue were recorded in Puerto Rico, 29 of which were serious, with 341 hospitalizations.
The infections are concentrated in cities, such as San Juan, Bayamon, Guaynabo and Carolina. Between 2010 and 2020, over 30,000 cases of dengue were reported in 4 US territories, including Puerto Rico which had the highest number of infections.
In 2012, 199 deaths were reported on the island, the last time the Commonwealth declared a dengue epidemic. The CDC, Centers for Disease Control and Prevention, explained that they are collaborating with the Puerto Rico Department of Health and the local Insect Vector Control Unit for the surveillance of the virus and the training of health workers. The CDC is also engaged in disinfestation campaigns, using insecticides where necessary, and educational initiatives.
Puerto Rico’s Department of Health said it is working to improve surveillance, laboratory activities, vector control and awareness interventions.
Alarm abroad too
After breaking the historical series record, concern about the spread of Dengue – according to some the new pandemic – goes beyond the borders of Brazil and is also growing abroad, where Italy is already at the forefront of prevention actions.
A case of Dengue has been recorded atSan Martino hospital in Genoa. «The patient arrived from Argentina, he is well and has no particular problems. We visited him, did the tests and then sent him home confirming the diagnosis. Having raised awareness through the media, the ministry’s circulars, allowed this gentleman to come to us precisely because he suspected he had the symptoms of Dengue. Providing information and dissemination on this topic is very useful for citizens” specified virologist Matteo Bassetti, director of infectious diseases at the San Martino polyclinic hospital in Genoa.
Meanwhile, Brazilian health authorities are relying on experience and early diagnoses to try to demonstrate that (despite the 561 deaths, half of the entire 2023) mortality in the country has reduced from 10% in 2016 to 0.2%.
But the reasons that caused the surge are to be found in those climate changes which in Brazil favor the faster reproduction of the mosquito, and which in southern Europe have led to tropicalisation, creating the conditions for the aedes aegypti mosquito responsible for the contagion to be able to adapt to the new environment by generating a viral mix of dengue, but also zika, yellow fever and chikungunya: all diseases transmitted by the tiger mosquito.
In recent years, cases of these pathologies in Italy have gone from a few dozen to a few hundred, with a notable increase in indigenous infections. «Last year we had 83 cases of patients who acquired the disease in Italy and not from abroad, this is obviously something that will tend to increase. Without alarmism, it is a significant problem”, said the scientific director of Simit, Massimo Andreoni.
For the professor of Hygiene at the Vita-Salute San Raffaele University of Milan, Gianni Rezza «it is right that we start to provide information if we go to an area where there is an endemic or an epidemic, in case we return with fever you also need to think about the illness. Making an early diagnosis is important, because people with the infection can be identified and disinfected around their homes.”
The possible local reproduction of the mosquito as the Italian summer approaches would in fact be the greatest risk. For the Italian government, the watchword is therefore not to let the insect enter the country. The Ministry of Health introduced extraordinary checks at airports in February to prevent dangerous mosquito specimens from disembarking together with passengers traveling from tropical regions.
A few days ago a new circular also introduced controls on goods arriving by sea, also requiring a certificate of disinfestation at the time of shipment for potential ‘containers’ of water capable of supporting the survival of insects, such as flowers, used tires or timber. The first dengue vaccine developed by Japan’s Takeda, available since last year, could offer a solution to the control of the disease now limited only to the vector.
For Andreoni in Europe it is not necessary. In Brazil yes, but despite the availability of the first doses, the start of the vaccination campaign was greeted with little enthusiasm, recording low participation. Only 35% of parents brought their children between the ages of 10 and 14 – the age group foreseen as a priority by the ministry – to be vaccinated. A delay that could aggravate the already complicated situation in the country where the peak of infections has not yet been reached. In fact, the authorities confirm that the peak will occur in May and if the advance of the disease is confirmed it will be able to exceed the projections of 4.2 million cases by the end of the year.
