Monkeypox is a rare viral zoonosis (a virus transmitted to humans from animals) with symptoms in humans similar to those seen in the past in smallpox patients, although less severe. Smallpox was eradicated in 1980.However, monkeypox still occurs sporadically in some parts of Africa.
Key facts
- Monkeypox is a rare disease that occurs primarily in remote parts of Central and West Africa, near tropical rainforests.
- The monkeypox virus can cause a fatal illness in humans and, although it is similar to human smallpox which has been eradicated, it is much milder.
- The monkeypox virus is transmitted to people from various wild animals but has limited secondary spread through human-to-human transmission.
- Typically, case fatality in monkeypox outbreaks has been between 1% and 10%, with most deaths occurring in younger age groups.
- There is no treatment or vaccine available although prior smallpox vaccination was highly effective in preventing monkeypox as well.
The Monkeypox virus enters the body through broken skin (even if not visible), respiratory tract or the mucous membranes (eyes, nose, or mouth).
Animal-to-human transmission may occur by bite or scratch, bush meat preparation, direct contact with body fluids or lesion material, or indirect contact with lesion material, such as through contaminated bedding. Human-to-human transmission is thought to occur primarily through large respiratory droplets.
Respiratory droplets generally cannot travel more than a few feet. So prolonged face-to-face contact is required.
Other human-to-human methods of transmission include direct contact with body fluids or lesion material, and indirect contact with lesion material, such as through contaminated clothing or linens.
Signs and symptoms
The incubation period (interval from infection to onset of symptoms) of monkeypox is usually from 6 to 16 days but can range from 5 to 21 days.
The infection can be divided into two periods:
- the invasion period (0-5 days) characterized by fever, intense headache, lymphadenopathy (swelling of the lymph node), back pain, myalgia (muscle ache) and an intense asthenia (lack of energy);
- the skin eruption period (within 1-3 days after appearance of fever) where the various stages of the rash appears, often beginning on the face and then spreading elsewhere on the body. The face (in 95% of cases), and palms of the hands and soles of the feet (75%) are most affected. Evolution of the rash from maculopapules (lesions with a flat bases) to vesicles (small fluid-filled blisters), pustules, followed by crusts occurs in approximately 10 days. Three weeks might be necessary before the complete disappearance of the crusts.
The number of the lesions varies from a few to several thousand, affecting oral mucous membranes (in 70% of cases), genitalia (30%), and conjunctivae (eyelid) (20%), as well as the cornea (eyeball).
Some patients develop severe lymphadenopathy (swollen lymph nodes) before the appearance of the rash, which is a distinctive feature of monkeypox compared to other similar diseases.
Prevention
There are measures that can be taken to prevent infection with monkeypox virus:
- Avoid contact with animals that could harbour the virus (including animals that are sick or that have been found dead in areas where the disease occurs).
- Avoid contact with any material, such as bedding, that has been in contact with a sick animal and solate infected patients from others who could be at risk of infection.
- Practice good hand hygiene after contact with infected animals or humans. For example, washing your hands with soap and water or using an alcohol-based hand sanitizer.
- Also use personal protective equipment when caring for patients.
Credit: WHO