Climate change, high population density in urban areas, migration, increased travel frequency, increased poverty and precarious living conditions are the most important factors for the development and persistence of dengue disease. , a condition that extends to areas where it was not before and that in the region of the Americas puts some 500 million people at risk.
On the occasion of the International Day Against Dengue, which is commemorated on August 26, the specialists underline the importance of implementing a comprehensive education and communication strategy to prevent the pathology, as well as training health personnel to avoid hospitalizations.
According to the Pan American Health Organization (PAHO), the number of dengue cases in the Americas has increased in the last four decades, going from 1.5 million accumulated cases in the 1980s to 16.2 million in the 1980s. from 2010-2019. In 2019, the organization pointed out, a little more than 3.1 million cases were registered, 28 thousand serious, and 1,534 deaths.
According to specialists, in many countries, depending on the factors involved, dengue could become endemic and, for this reason, they emphasize the need to strengthen epidemiological surveillance in addition to controlling the health of environments in general and the microenvironments of particular people.
“If we observe the pattern of distribution of dengue with the increase in incidence in recent years, the spread to other areas where it was not previously, added to changes in climate and unfavorable social and economic conditions, it is very likely that, in the future, we will have more areas with people who present the disease and a greater number of cases,” warned Dr. Pablo Bonvehí, infectologist, member of the Technical Advisory Group on Vaccine-preventable Diseases (TAG, for its acronym in English). PAHO and Head of Infectious Diseases at CEMIC University Hospital.
What is dengue?
Dengue is a viral disease transmitted by a mosquito of the Aedes group, more precisely Aedes aegypti and, to a lesser extent, Aedes albopicus. There are 4 different serotypes of dengue (DENV-1, DENV-2, DENV-3 and DEN-V 4), with which a person can be infected by each of these. Being infected by one of the serotypes not only does not protect the individual against the rest, but also presents a greater risk of suffering a severe form when infected by another serotype. There is currently no specific medication to treat dengue.
In many countries, depending on the factors involved, dengue could become endemic
“In the region of the Americas, the largest peak occurred in 2019 and the most affected countries were those with a more tropical climate, that is Central America: Mexico, Costa Rica, Honduras, Nicaragua, Belize, also Venezuela, Colombia, Paraguay, Bolivia and Brazil, the latter always with the highest number of cases, are countries that usually have a high burden of disease, and from that outbreak in 2019, in Argentina the cases began to increase towards the end of that year, and the highest peak was occurred in 2020, coinciding with the start of the Covid 19 pandemic. The febrile cases that we had were practically all cases of dengue, this greatly complicated the situation, it was a particular year, not only because it was the one with the highest number of dengue cases , but because it got worse because, on the one hand, people did not want to come to consult for fear of Covid, and on the other hand, we had a lot of health personnel reassigned to the contingency of the pandemic,” said Dr. Analía Urueña, doctor ca infectologist and Director of the Center for Studies for the Prevention and Control of Communicable Diseases (CEPyCET) of the Isalud University.
For both specialists, education and communication are key for the population to identify the best methods to prevent the development of the mosquito: descaling and preventing water from collecting throughout the year, since in winter the larvae persist and then they can be mosquitoes that transmit the virus. People and also municipal authorities must avoid the accumulation of garbage and favor access to drinking water, encourage the use of repellents and mosquito nets and periodically change animal waterers.
As detailed by Dr. Bonvehí, dengue outbreaks do not occur every year, since the epidemiology is changing. In general, outbreaks occur every 3 to 5 years. “In Argentina, the most affected areas until a few years ago were the NEA (Misiones, Formosa, Chaco and Corrientes) and some Northwest provinces, especially the Orán area in Salta. However, we have seen in the last two outbreaks 2015- 2016 and 2019-2020 that this has been moving towards the central zone of the country; we had outbreaks in provinces such as Córdoba, Santa Fe and in the Metropolitan Area of Buenos Aires as well, caused by higher population density and climate change, among others In other words, dengue is spreading throughout the world and also in our country, which is why we have a high percentage of people who are at risk or who have already been infected and are at risk of a second episode that could become more serious,” he reported.
Dengue: the symptoms
Dengue disease presents with an acute and nonspecific febrile illness. It is so called because it lasts less than 7 days, without respiratory symptoms.
These signs usually include severe headache, pain behind the eyes, muscle and joint pain, and sometimes diarrhea or vomiting; also sometimes a rash appears on the skin.
“A person who presents these symptoms without respiratory manifestations should think that it could be dengue and whoever assists him in the health center, too. To make the diagnosis, there are different laboratory techniques, a blood sample can be taken and analyzed; the technique It will depend on the epidemiological context and the time of evolution of the symptoms.Usually the clinical picture is of outpatient management and the symptoms subside in a few days, however, on some occasions it can be complicated and evolve into a severe dengue picture with organ involvement , respiratory distress or shock.To prevent this situation, health personnel should pay attention and alert about certain warning signs that usually appear when the fever goes away, and this is not minor, because when the fever subsides is when dengue can worsen,” warned Dr. Urueña.
Dengue disease presents with an acute and nonspecific febrile illness
Warning signs include intense or continuous abdominal pain, persistent vomiting, mucosal bleeding, irritability or drowsiness, and pleural effusion, all situations that should be detected in the consultation. Fortunately, the case fatality of dengue is generally low, less than 0.1 percent. “It is a disease that generally does not kill, because if adequate hydration is provided in time, no one should die of dengue,” the specialist stressed.
In Argentina, the peak of infections occurred in 2020
In 2020, the peak of infections in Argentina represented some 56 thousand infections (between probable and confirmed) without travel history. Currently, according to the latest epidemiological reports, for the 2021-2022 season (up to week 32 of 2022), 789 cases with no history of travel abroad were confirmed, all of them during 2022. The cases occurred in Salta, Buenos Aires, Santa Fe, Córdoba, Santiago del Estero and Misiones. Salta contributed 77% of the confirmed cases, followed by Buenos Aires with 19% and Santa Fe with 3%. Although the cases were distributed between weeks (EW) 04 and EW 23 of 2022, 62% were concentrated between EW 14 and 18. According to the report, no deaths were recorded. In addition, the serotype of 30% of the cases was studied and it was observed that 89% corresponded to DEN-2 (Salta and one case in Santiago del Estero) and the remaining 11% to the DEN-1 serotype (Buenos Aires, Santa Fe and Cordoba).
“If we take into account that the last outbreak was towards the end of 2019 and the beginning of 2020, we are almost three years away, so we must be vigilant. In Brazil, in the State of Paraná, a significant number of cases have already been registered. We have to strengthen epidemiological surveillance, because it helps us detect the appearance of outbreaks early and work on training health personnel for adequate care: it has been shown that in those places where there is training and education, mortality and hospitalization rates are higher. Environmental control in general and the microenvironment of each person is also important,” said Dr. Bonvehí, who is also a member of the Vaccine Committee of the Argentine Society of Infectious Diseases (SADI).
According to the specialists, it is necessary to be clear that dengue is not only a problem in one region of Argentina, but in the entire country due to the great mobility, population density, climate change and the presence of the vector in almost the entire territory.
We must not remember dengue only when we are in outbreak but throughout the year and keep in mind that dengue is here to stay and that it is going to be an increasingly complex problem; we must support prevention measures, study and report cases to the Surveillance System in a timely manner, this is essential, because when cases begin in the north or in neighboring countries, the entire rest of the country must be alert, since the most of our territory can be affected by dengue,” concluded Dr. Urueña.