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On alert for monkeypox



A RARE VIRAL INFECTION found primarily in Africa, monkeypox was diagnosed for the first time in the United States in the spring of 2003. The outbreak, which affected people in six midwestern states, was traced to pet prairie dogs who'd become infected when they were housed near a shipment of African rodents.

The monkeypox virus belongs to a group of poxviruses that includes variola major, which causes smallpox, and vaccinia, which is used in the smallpox vaccine. The smallpox vaccine is considered about 85% effective against monkeypox.

Although monkeypox and smallpox cause similar signs and symptoms in humans, monkeypox is far less virulent and has a low mortality rate. After the 2003 outbreak, the federal government banned the import of African rodents and the sale of prairie dogs to minimize the risk of future outbreaks.

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From exposure to recovery

The median incubation period after exposure to monkeypox is 12 days. Early signs and symptoms include flulike symptoms (fever, muscle aches, and backache) and swollen lymph glands—which, unlike most other signs, isn't typical of smallpox. About 3 days later, a vesicular rash appears. Usually (but not always) it starts on the face and spreads to other parts of the body. As with smallpox, the lesions go through several stages and then form scabs, which eventually fall off. Illness lasts from 2 to 4 weeks. The diagnosis may be confirmed with polymerase chain reaction–based assays, serologic testing, electron microscopy, immunohistochemistry, and gene sequencing.



According to the Centers for Disease Control and Prevention (CDC), person-to-person transmission of monkeypox hasn't been documented in the United States, but the disease is potentially transmissible through infected blood or body fluids, respiratory droplets or saliva, lesions, and fomites (bedding and other articles harboring infectious matter). Unless contraindicated, the CDC recommends the smallpox vaccine for anyone who's had contact with a human or animal with a confirmed case of monkeypox.

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Providing supportive care

Care for a patient with monkeypox is supportive. Place him in a negative-pressure room (preferably) or a private room and initiate contact, droplet, and airborne precautions. Use a face shield or goggles if splashing or spraying of body fluids might occur. Strictly follow infection control protocols for hand hygiene and disinfection or disposal of equipment and fomites.

If a patient with monkeypox is recovering at home, he should be isolated in his home; he should stay in a private room and minimize contact with others if he has respiratory symptoms or lesions that aren't easily covered. Teach his caregivers to follow strict hand hygiene and other infection control measures, including the use of personal protective equipment as appropriate. To prevent infection hazards from fomites, provide this advice to patients and their families:

  • Don't shake bedding, towels, or clothing, which may release airborne droplets.
  • Launder bedding and clothing with warm water in the washing machine and dryer. Bleach may be added, but isn't required.
  • Don't share dishes or eating utensils with the patient. Clean the patient's dishes and utensils as usual in a dishwasher or by hand with soap and warm water.
  • Clean and disinfect contaminated surfaces with a standard household disinfectant.
  • Place soiled dressings and disposable medical equipment in a plastic bag and place it in another container for disposal with the household trash.

For complete guidelines, see the CDC Web site below.

Michelle Snow is president of CNA Educational Services in Kaysville, Utah.

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Centers for Disease Control and Prevention

Last accessed on February 7, 2005.

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Guarner J, et al. Monkeypox transmission and pathogenesis in prairie dogs. Emerging Infectious Diseases. 10(3):426–431, March 2004.
Sejvar J, et al. Human monkeypox infection: A family cluster in the midwestern United States. The Journal of Infectious Diseases. 190:1833–1840, electronically published October 12, 2004.
    © 2005 Lippincott Williams & Wilkins, Inc.