Monkeypox is a zoonotic disease; that is, a virus transmitted from animals to humans. Many infectious diseases are zoonoses; for example, COVID-19 is believed to be one too. This virus is mainly present in the tropical forests of central and western Africa, where some mammals such as primates or rodents can transmit it to humans, and it rarely spreads to other regions. The risk factors for infection are: having travelled to areas such as the Congo or Nigeria and returning with an infection, or having been in contact with infected wild animals. At the present time, cases have been found in people who have not travelled to Africa and possible triggers and transmission chains are being studied. Until now, the cases that have been recorded mainly involve men who have sex with men. The Ministry of Health and the European Centre for Disease Control (ECDC) have alerted Spain, Portugal, Sweden, Canada, the United States and the United Kingdom about various infections.
Monkeypox is similar to smallpox - eradicated in 1980, thanks to the vaccine, but is clinically less serious, and more frequent in children. Symptoms are fever, swollen lymph nodes and a skin rash that progresses to clearly visible blisters. Most of the cases diagnosed so far have been concentrated in rural areas of that region and in some African countries, such as Nigeria.
This virus is transmitted by droplet contact; that is, by close contact with lesions, body fluids and other contaminated materials from infected animals or people. The incubation period is 6-13 days, and symptoms last 2-4 weeks. It starts with fever, headache and myalgia, followed by a skin rash concentrated mainly on the face and extremities. The rash evolves from lesions with a flat base to lesions in the form of fluid-filled vesicles that subsequently dry up and fall away.
The smallpox vaccine also confers protection against monkeypox, with an effectiveness of 85%. However, this vaccine stopped being given once the disease was eradicated 40 years ago. Nevertheless, a new smallpox vaccine, of a modified live virus called IMVANEX, was approved in 2019. It is not available for the general public, as it is intended for use in emergencies following official recommendations.
For now, the outbreaks are self-limiting; however, their origin must continue to be studied and any suspicious cases detected should be confirmed. The Department of Health is on alert and ready to act with preventive measures such as vaccination. A PCR test is the most sensitive and accurate available for the monkeypox virus. An antigen detection test does not provide results that confirm the presence of the virus and is not recommended for detection.
Documented information: Dr. Antoni Trilla Senior Consultant and Dr. Anna Vilella Head of the Preventive Medicine and Epidemiology Service of the Hospital Clínic - University of Barcelona.