2023-04-16 09:01:09
The latest data from dengue published by the Ministry of Health in the weekly Epidemiological Bulletin, not only revealed the first two deaths in the City of Buenos Aires, bringing the total in the country to 35, but also finally explained why this epidemic of 2023 is more aggressive, deadly and grows faster than the previous ones.
The key is that of the more than 41 thousand cases of dengue so far, some 30 mil correspond to serotype 2. It means the 73 percent. More than 7 out of 10 infections are occurring with a strain that is the worst of all. Of the total deaths this year, the 76 percent corresponds, effectively, to the DENV-2 serotype.
The medical literature gives an account of this characteristic of the disease: serotype 2 is the most harmful and capable of producing serious pictures dengue, even if it is a first infection. In addition, it contributes to greater circulation, something that is confirmed in the current epidemic compared to those of 2016 and 2020.
The dengue virus can have up to four serotypes and this year, according to the Ministry of Health, in Argentina they circulate the 1 and 2. Unlike previous epidemics, the bad news is that this is the first time that DENV-2 is predominantso the damage from the disease is obviously greater.
This is also linked to the fact that people who have contracted dengue in the past are more susceptible in the event of a second infection. In 2016 and 2020, DEN-1 predominated. Now, the protagonist is the DEN-2. However, beyond this risk-enhancing element, it is key the virulence of the strain in action today, as with the Covid was the lethality of the variant on duty.
A work published in the journal Archivos Argentinos de Pediatría, signed by the infectologist Griselda Berberian, describes the behavior of dengue serotypes in the latest epidemics in the country. This historical comparison allows us to understand why what is happening now is something unprecedented.
“In the first outbreak of the 2008-2009 season -says Berberian-, 26,700 cases of dengue were reported in Argentina. DENV-1 predominated, whose most important focus was in the NOA region. Seven years later, in 2016, the second dengue outbreak occurred, with 41,749 cases; the NEA was added”.
The expert continues with a precision that is key to understanding the phenomenon: “Four years later, in 2020, the third major dengue outbreak occurred, with 59,277 cases, with the isolation of DENV-1 (el 72 %) mostly, but already diversifying the serotypes with DENV-4 (26%) and DENV-2 (2%)”.
That is to say that the current ratio among circulating serotypes It is practically the opposite of what was recorded in 2020, the year in which there were 26 deaths throughout the season. Now at least 35 deaths are reported. In 2016, on the other hand, there were 11 deaths and in 2009, 2.
The death figures during the 2020 epidemic, even though serotype 1 predominated then, were not marginal. For this reason, an official government guide for health teams indicates that this strain can also cause cases of severe dengue. Although lower proportion than DENV-2.
Other data is consistent with this new scenario. The provinces with the most deaths this year are Salta (10) and Tucumán (9). In both circulates only serotype 2which is present in 10 districts, while DENV-1 was reported in 7. Both strains circulate in the City and the province of Buenos Aires.
According to another article published in the Cuban Journal of Tropical Medicine, “several studies have shown that the frequency of hemorrhagic cases during a dengue epidemic depends on the virus strain. Therefore, monitoring the temporal distribution of serotypes and subtypes in endemic areas provides information on the risk of DHF (N. de la R.: dengue hemorrhagic fever)”.
The scientists’ explanation continues that “DENV-2 is the serotype that with higher frequency it produces severe cases followed by DENV-3, DENV-1 and DENV-4, but there are differences in virulence potential between strains. DENV-2 subtype III and DENV-3 subtype III viruses are those who isolate themselves the most of severe cases”.
So that the epidemiological scenario of Argentina, from the predominance of DENV-2, has been transformed from previous experiences with dengue, so the usual prevention measures are still important but are not enough. Avoiding the accumulation of water in containers or using repellent would not be enough to stop the virulence and transmissibility of the virus.
Especially taking into account that the population that lives below the poverty line is increasing in the country and the so-called junk becomes an increasingly difficult goal to achieve. meanwhile there are two dengue vaccinesbut in Argentina they are not available.
The balance of deaths does not stop growing. Although the National Bulletin counts 27 in total, the provincial reports already add 35 in nine districtsdistributed as follows: Salta (10), Tucumán (9), Santa Fe (5), Córdoba (2), Jujuy (4), CABA (2), Buenos Aires (1), Entre Ríos (1) and Santiago del Estero (1).
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