The monkeypox outbreak has been declared a global health emergency by the World Health Organization. More than 16,000 cases have now been reported from 75 countries.

The first outbreak of Monkeypox emerged in 2003. In this outbreak, all people infected with Monkeypox became ill after contacting pet prairie dogs.

A new study published in The BMJ identified significant differences in monkeypox symptoms between the current outbreak and previous outbreaks in endemic regions. The results are drawn on 197 confirmed cases of Monkeypox recorded between May and July 2022 at an infectious disease center in London.

Some common symptoms, including rectal pain and penile swelling (oedema), differ from those described in previous outbreaks.

Therefore, the scientists advise clinicians to take monkeypox infection into account in individuals exhibiting similar symptoms. Additionally, they state that individuals with extensive penile lesions or significant rectal pain associated with a confirmed monkeypox infection “should be considered for continuous assessment or inpatient management.”

All 197 participants in this study were men (average age of 38 years), of whom 196 identified as gay, bisexual, or other men who have sex with men. All patients presented with skin or mucosal membranes lesions, most commonly on the genitals or the perianal area.

Most (86%) patients reported systemic illness (affecting the entire body). The most common systemic symptoms were fever (62%), swollen lymph nodes (58%), and muscle aches and pain (32%).

In addition, 38 percent of patients experienced systemic symptoms following the development of mucocutaneous lesions, in contrast to previous reports that suggested systemic symptoms come before skin lesions, whereas 14 percent presented with lesions devoid of systemic signs.

Seventy-one patients experienced rectal pain, 33 sore throats, 31 penile oedema, 27 oral lesions, 22 solitary lesions, and nine swollen tonsils.

Scientists noted, “Solitary lesions and swollen tonsils were not previously known to be typical features of monkeypox infection, and could be mistaken for other conditions. Just over a third (36%) of participants also had HIV infection, and 32% of those screened for sexually transmitted infections had a sexually transmitted infection.”

“Overall, 20 (10%) of participants were admitted to hospital to manage symptoms, most commonly rectal pain and penile swelling. However, no deaths were reported, and no patients required intensive hospital care.”

“Only one participant had recently traveled to an endemic region, confirming ongoing transmission within the UK, and only a quarter of patients had known contact with someone with confirmed monkeypox infection, raising the possibility of transmission by people with no or very few symptoms.”

The authors acknowledge some limitations, such as the observational nature of the findings, the potential variability of clinical record keeping, and the fact that the data are limited to a single center.

“However, the findings confirm the ongoing unprecedented community transmission of monkeypox virus among gay, bisexual, and other men who have sex with men seen in the UK and many other non-endemic countries.”

Journal Reference:

  1. Patel A, Bilinska J, Tam J C H, Da Silva Fontoura D, Mason C Y, Daunt A et al. Clinical features and novel presentations of human Monkeypox in a central London center during the 2022 outbreak: descriptive case series. BMJ 2022; 378:e072410. DOI: 10.1136/BMJ-2022-072410