Week 5: Signs and Symptoms

What are the signs and symptoms of monkeypox?
In humans, the signs and symptoms of monkeypox are like those of smallpox, but usually they are milder. Another difference is that monkeypox causes the lymph nodes to swell.

About 12 days after people are infected with the virus, they will get a fever, headache, muscle aches, and backache; their lymph nodes will swell; and they will feel tired. One to 3 days (or longer) after the fever starts, they will get a rash. This rash develops into raised bumps filled with fluid and often starts on the face and spreads, but it can start on other parts of the body too. The bumps go through several stages before they get crusty, scab over, and fall off. The illness usually lasts for 2 to 4 weeks.

The incubation period (interval from infection to onset of symptoms) of monkeypox varies from 6 to 16 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 where the various stages of the eruption appear on the face (in 95% of cases), on the palms of the hands and soles of the feet (75%) and on the body nearly simultaneously. 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 elimination 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. The presence of lymphadenopathy can help identify the disease as monkeypox since it is not characteristic of either smallpox or chickenpox.

The symptoms of monkeypox usually last from 14 to 21 days.

The case fatality has varied widely between epidemics but, has been less than 10% in documented cases. Most fatalities occur in young children. In addition, children may be more susceptible to monkeypox due to the termination of regular smallpox vaccinations following the worldwide eradication of the disease in 1980.

References:
Monkeypox. (2011, February 1). Retrieved March 30, 2015, from http://www.who.int/mediacentre/factsheets/fs161/en/
 Updated Interim Infection Control and Exposure Management Guidance in the Health-Care and Community Setting for Patients with Possible Monkeypox Virus Infection. (2008, September 5). Retrieved March 31, 2015, from http://www.cdc.gov/ncidod/monkeypox/infectioncontrol.htm