The World Health Organization issued its first situation report on the spread of monkeypox on Thursday, detailing the typical profile of those affected by the outbreak so far.

According to available statistics, almost all patients affected thus far are male, with a median age of 37, with three-fifths identifying as men who have sex with men, the WHO said.

A surge in monkeypox infections has been reported since early May outside the West and Central African countries where the disease has long been endemic.

From January 1 to July 4, 6,027 laboratory-confirmed cases of monkeypox and three deaths have been reported to the WHO from 59 countries.

Case numbers have gone up by 77 percent since June 27, in which time two new deaths -- both in the Central African Republic -- have been reported.

The WHO said 10 countries have not reported new cases for more than 21 days -- the disease's maximum incubation period.

Some 82 percent of the cases are in Europe and 15 percent are in the Americas.

The countries with more than 1,000 confirmed cases are Britain (1,351), Spain (1,256) and Germany (1,242), according to the European Centre for Disease Prevention and Control, and WHO Europe.

Outside Europe, the WHO report counted 460 confirmed cases in the United States and 300 in Canada.

Sexual contact transmission route 

In its first bi-weekly situation report on monkeypox, the WHO said that gender data was available on 4,406 cases, of which 99.5 percent were men.

"The outbreak continues to primarily affect men who have sex with men who have reported recent sex with one or multiple male partners, suggesting no signal of sustained transmission beyond these networks for now," the report said.

Men aged 18 to 44 account for 79 percent of cases, with the median age being 37.

There are six known cases among children aged under 18, and 25 known cases among healthcare workers.

"Among cases with reported sexual orientation, 60 percent (1,214 out of 2,025) identified as gay, bisexual and other men who have sex with men; and 41 percent (335 out of 827) of cases with known HIV status were positive for HIV," the report said.

"The most often suspected and reported route of transmission, among known contacts, has been through sexual contact."

Atypical symptoms 

The normal initial symptoms of monkeypox include a high fever, swollen lymph nodes and a blistery chickenpox-like rash.

But the report said that in this outbreak, many cases were not presenting with the classically described clinical picture.

Among the cases who reported at least one symptom, 81 percent presented with a widespread rash on the body, 50 percent presented with fever and 41 percent presented with genital rash.

Testing data indicate that the monkeypox virus genomes belong to the West African type, which is milder than the other Congo Basin group.