Smallpox of monkeys, cases without symptoms and contagion in crowded gatherings -

from Silvia Turin

The ways of transmission of the virus that can escape monitoring are studied: two studies investigate people without symptoms and the passage of the virus by "simple" contact, without sexual intercourse

The epidemic of the monkeypox is spreading around the world: the estimate communicated on August 17 by the World Health Organization (WHO) is more than 35 thousand cases in 92 countries with 12 deaths. At least 7,500 cases were reported last week, a 20% increase compared to the previous week, which in turn was 20% more than the week before.

What do we know about the infection

In this context, the transmission of the viruswhich - we remember - occurs above all with direct skin-to-skin contact, in particular, the strait intimate contact between sexual partners. Sexual contact is the primary way the virus is spreading, but not the only one (we talked about it extensively who) and, in the context of a sexual encounter, multiple transmission mechanisms are possible: contact with lesions, exchange of body fluids, inhalation of respiratory droplets; differentiating them is difficult.
Two recent studies have focused on two rare possibilitiesbut which can help to clarify the peculiarities of transmission of the virus (which in the US has also affected 7 children): the presence of asymptomatic and transmission by contact to a crowded event (without sexual intercourse).

Without injuries and without symptoms

The first study, published in the scientific journal Annals of Internal Medicine on August 16, he retrospectively examined anorectal samples from men who had had sexual intercourse with the male population in Paris and had undergone a surveillance program for sexually transmitted bacterial infections. Among these, 13 out of 200 (equal to 6.5% of the sample) tested positive for monkeypox, but they were completely asymptomatic. Of those who tested positive, 8 were living with HIV. Over the next 21 days, none (except two) developed symptoms suggestive of smallpox infection. It is not known whether asymptomatic people were also able to transmit the virus, since lesions are the main vehicle of infection, but they are not the first known "asymptomatic" subjects: a group of Belgian researchers retrospectively tested anal swab samples from 224 patients who had visited a hospital in July. clinic dealing with sexual diseases. In 3 of these samples, monkeypox was detected and none of these men ever developed the disease or exhibited the typical symptoms.
This leads to hypothesize one possible transmission of the virus that could be difficult to monitor, even if there are no certainties about it.

The gatherings under the lens

The second study was expected in the October issue of the journal Emerging Infectious Diseases and made available on a preliminary basis by the Centers for Disease Control and Prevention (CDC). Researchers from the Stanford University School of Medicine analyzed the case of a man infected with monkeypox whose main risk factor was close and non-sexual contact with numerous unknown people during a crowded outdoor event. This is a man in his twenties who went to an emergency room in Stanford after a recent trip to the UK. The first injury appeared about 14 days after he attended the large and crowded outdoor event during which he had close contact with the others. The boy reported that many of the participants were in tops and shorts. He did not notice any skin lesions on any of those present. He shared an e-cigarette with a woman, attended other similar outdoor events for 4 days. The events were not described as "rave" and "would not have been attended specifically or primarily by people who identified as gay or bisexual," said the young man, who has not reported recent sexual contact during his travels or in the 3 months. previous.

Positive nasal swabs with no respiratory symptoms

The boy had multiple skin lesions on his body, but not on the private parts. The test for smallpox with a bladder fluid was positive and also the test with nasopharyngeal sample. Three days after these tests, a sample of saliva, as well as conjunctival and rectal swabs. The patient then tested positive for monkeypox virus DNA in several samples without lesions. The nasopharyngeal and salivary findings were considered noteworthy by the scholars because the patient reported no respiratory symptoms. The main risk factor had been close, non-sexual contact with numerous strangers during a crowded outdoor event. 'The lack of both sexual exposure and anogenital involvement indicates that the mode of transmission may be associated with clinical symptoms; supplies (hotel sheets and sheets, high-contact areas in public environments) can be alternative modes of transmission, ”the study authors write.
Another important piece to understand thetransmission of monkeypox, as far as i cases described (including those of asymptomatic people above) are rare. Last advice from the researchers, that of increasing local tests on monkeypox, rather than centralized tests in reference laboratories: "Local tests allowed diagnosis in less than 12 hours and immediate notification to local public health authorities and state for isolation and contact tracing, ”they write as a diagnostic suggestion.

August 18, 2022 (change August 18, 2022 | 14:13)