| The Department of Health has prepared the following FAQ (Frequently Asked Questions) to help health care professionals address concerns about monkeypox in their everyday contact with patients. |
Monkeypox is a rare, zoonotic, viral disease that occurs primarily in the rain forest countries of Central and West Africa. In 1970, monkeypox was reported in humans for the first time. In June 2003, an outbreak of human monkeypox infection was reported in the United States among people who had history of contact with pets (including prairie dog, Gambian rat, rabbit) sick with monkeypox infection. There has not been any reported case of monkeypox in Hong Kong. Animal species susceptible to monkeypox virus may include non-human primates, rabbits and some rodents.
The disease is caused by monkeypox virus, which belongs to the genus Orthopoxvirus of the family Poxviridae.
In humans, infection with monkeypox virus results in a rash illness similar to but usually milder and less infectious than smallpox. Unlike smallpox, monkeypox causes cervical or inguinal or generalized lymphadenopathy.
The incubation period is between 7 - 17 days, usually 12 days. The illness begins with fever, headache, muscle aches, backache, swollen lymph nodes, a general feeling of discomfort, and exhaustion. Within 1 - 3 days after the appearance of fever, the patient develops a papular rash, often first on the face but sometimes initially on other parts of the body. The monkeypox rash includes macules, papules, vesicles, pustules and crusts that evolve in the same stage over 14 - 21 days. The case-fatality ratio may range from 1% - 10%.
Monkeypox can spread to humans from an infected animal through an animal bite or direct contact with the animal's lesions or body fluids. The disease also can be spread from person to person although it is much less infectious than smallpox. The virus is thought to be transmitted by respiratory droplets during direct and prolonged face-to-face contact, or by direct contact with body fluids of an infected person or with virus-contaminated objects, such as bedding or clothing. Secondary attack rate among household contacts was reported to be about 8%. The patient is not infectious during the incubation period.
Orthopoxvirus can be detected in vesicular or pustular fluid by electron microscopy. Monkeypox virus can be differentiated from other orthopoxviruses by polymerase chain reaction technique and gene sequencing. These tests are available at the Government Virus Unit.
Currently, there is no specific treatment for monkeypox. Smallpox vaccine has been reported to reduce the risk of monkeypox among previously vaccinated persons in Africa. Pre-exposure vaccination for prevention of monkeypox is not recommended for the general public because there has not been any human monkeypox infection reported in Hong Kong and there may be serious side effects from smallpox vaccination. The Centers for Disease Control and Prevention recommended post-exposure vaccination in the recent outbreak of human monkeypox infection in the United States.
Persons seeking medical care with unexplained fever, rash or lymphadenopathy should be asked about exposure to small mammals especially prairie dogs or Gambian rats. Refer the patient with suspected monkeypox to hospital and report the case to the Department of Health.
Department of Health
16 June 2003