Four months of epidemic and a total of infections that globally exceeded the threshold of 42 thousand units represent a sufficient knowledge base to estimate the epidemiological characteristics of the wave of monkeypox cases that is affecting Europe and the United States .
Characteristics of patients, incubation times, the ability of the virus to jump from one individual to another: knowledge of these aspects is salient for a correct health management of the epidemic. Aspects that today are starting to be known, thanks also to a work carried out in Italy. The results, published in the journal “Emerging Infectious Diseases”, confirmed some characteristics of the infection (target population, mode of contagion, disease course) and revealed new ones (incubation and generation time, reproduction number). Hence the authors’ conclusions: “Maintaining a high level of public attention and providing non-stigmatizing information to at-risk population groups are key aspects to contain the spread of monkeypox.”
Monkeypox, Covid and HIV: the strange case of the Italian who has three infections at the same time
by Fabio Di Todaro
Smallpox of monkeys: 740 cases in Italy
The study was conducted by a group of researchers from the Bruno Kessler Foundation of Trento, the Ministry of Health, the National Institute for Infectious Diseases (INMI) Lazzaro Spallanzani in Rome and the regional health directorates of Lombardy and Emilia. Romagna. Starting point of their work, the first 255 cases of monkeypox recorded in Italy from the beginning of May until July 8.
A figure, the epidemiological one, which in the meantime has almost tripled. In fact, 740 infections have been ascertained up to Friday 26 August along the boot. Lombardy (318), Lazio (136), Veneto (49) and Tuscany (38) are the most affected regions. Five are those who, at the moment, have not reported even one case of infection. These are Basilicata, Calabria, Molise, Umbria and Valle d’Aosta.
Almost all male patients
Returning to work, the researchers confirmed an epidemiological datum common to all the countries most affected by this epidemic wave. Even in Italy, patients are mostly men (253 out of 255). And in more than 9 out of 10 cases – among those considered in the study – they were homosexuals, bisexuals and transsexuals. Categories of people who, in the clinical setting, fall into the “MSM” group. That is: men who have sex with men.
Average age: 37 years, with borderline cases of 20 and 71 years respectively. Twenty-five of them (therefore less than ten percent of the total sample) were returning from a trip to the Canary Islands, where it is assumed that a meeting held in May represented the “amplification” event of this epidemic. However, with the exception of another patient returning from a trip to West Africa, 60 percent of the cases recorded in Italy up to mid-July were indigenous. That is the result of an inter-human contagion that took place on the national territory.
Monkey pox, beware of contagion through linen
by Valentina Arcovio
Incubation less than ten days
Rashes, mostly in the genital and perianal area, were found in 139 of the 184 cases for which such information was available. A sign that in these cases the infection most likely occurred through contact during sexual intercourse. Fever was detected in 151 patients instead.
More generally, the symptoms appeared on average after nine days: hence a first estimate of the incubation time of the infection, which elapses between the presumed contagion and the onset of symptoms. Beyond the individual variability, in almost all cases this time frame (during which it is necessary to monitor the appearance of symptoms between the close contacts of the positives, for an early diagnosis of new cases) was in any case less than twenty days.
Another estimate put forward by researchers – including epidemiologists Stefano Merler e Giorgio Guzzetta of the Kessler Foundation e Gianni Rezza, Director General of Prevention of the Ministry of Health – was concerned with the generation time. That is what passes between the infection in a patient and the infections generated by the same.
According to the study authors, this period amounts to an average of 12.5 days. And it is the one during which “each patient must remain in isolation, while conducting the contact tracing activities”. Finally, on the basis of the data collected, each positive person would be able to infect just over two (reproduction number).
Monkey pox, can be asymptomatic
by Fabio Di Todaro
The risk remains low in the general population
With respect to this scenario, the researchers observed two aspects that should not be overlooked. The first refers to the decline in the number of reproduction, which has been underway since mid-June. One aspect that could be playing a role is “the incompleteness of data” as well as “an increase in the levels of attention and awareness of people who fall into the category of MSM”. In fact, these are men who are on average more sensitive to the risk of contracting sexually transmitted infections. And therefore they may have taken actions aimed at reducing the risk of coming into contact with monkeypox: from limiting the number of partners to using condoms.
Another food for thought advanced in the work concerns the reproduction number, estimated only among MSMs. “In the general population, however, it could also be less than 1: therefore below the epidemic threshold”, conclude the researchers.
Twitter @fabioditodaro
Monkey pox from humans to animals, should we worry?
by Donatella Zorzetto
