Monkeypox underscores infection risk to HCWs

Spread can occur before disease is recognized

Reports of possible hospital transmission of monkeypox once again highlight the risk of newly emerging infectious diseases for health care workers and the need for vigilant infection control and swift identification of cases.

In June, Wisconsin reported two possible cases of monkeypox in health care workers but then noted that the details of the cases indicated that they were actually not linked to the outbreak. Monkeypox is in the same family of viruses as smallpox, but it is not as easily transmitted and is less likely to be fatal.1

Nonetheless, public health officials urged health care workers to wear gloves, gowns, masks, and goggles when treating patients with known or suspected monkeypox. They emphasized the importance of hand hygiene to prevent spread from lesions or contaminated clothing and surfaces.

Those recommendations came as experts from the Centers for Disease Control and Prevention continued to investigate hospital-based outbreaks of severe acute respiratory syndrome (SARS) in Toronto and to evaluate the effectiveness of protective gear. CDC experts also suggest that surface contamination and hand hygiene may play an important role in SARS spread.

One lesson learned from both events: Health care workers should view unusual symptoms with a high index of suspicion.

"We try to work as fast as we can to identify unusual diseases and try to put in place the precautions we can," says Bruce Cunha, RN, MS, manager of employee health and safety at the Marshfield (WI) Clinic, which treated the first case of monkeypox.

Missed diagnoses can put both health care workers and other patients at risk. In Toronto, SARS-like symptoms in five members of a family went undetected until late May, triggering a new outbreak. About a dozen nurses developed SARS symptoms from that case.

Beth Israel Medical Center-Kings Highway Division in Brooklyn, NY, recently reported an outbreak of scabies that affected nurses, physicians, and staff in housekeeping, engineering, and physical therapy. Two patients had been admitted to the emergency department with skin rashes that were not immediately recognized as scabies.2

CDC: Smallpox vaccine effective protection

The first monkeypox case — a three-year-old girl who had been bitten by a prairie dog — was actually diagnosed fairly quickly at Marshfield Clinic. Physicians knew they were looking at a possible case of animal-to-human transmission. They considered cellulitis and ruled out plague and tularemia. The clinic then identified the monkeypox virus by electron microscopy.

The medical assistant who took the child’s vital signs and held her on her lap did not use infection control precautions. Weeks later, she developed a headache, backache, chills, muscle weakness, and diarrhea, and her boyfriend developed similar symptoms. "It does not seem to represent a case of monkeypox," says Wisconsin state epidemiologist Jeffrey Davis, MD.

Laboratory tests showed no anti-orthopoxvirus immune reactivity or monkeypox-specific DNA signatures, though testing was continuing, the CDC reported.3

CDC has recommended that health care workers and others who have unprotected exposure to monkeypox patients or sick animals receive the smallpox vaccine. Health care workers who have unprotected exposure should undergo active surveillance for symptoms, including taking their temperature twice a day for 21 days, the CDC said. "Prior to reporting for duty each day, the health care worker should be interviewed regarding symptoms and have their temperature measured by employee health or other designee."4

Health care workers with protected exposure also should take their temperature at least twice daily and be on the alert for symptoms, the CDC recommendations state.

By late June, 79 cases of suspected monkeypox had been reported in Wisconsin, Indiana, Illinois, Missouri, and Ohio; 31 were confirmed through laboratory tests, and tests were pending on the others. The common symptoms: a papular rash, fever, cough or shortness of breath, swollen lymph glands, and sore throat. Most patients did not become seriously ill, although one child suffered from severe encephalitis, the CDC reported.

The CDC and U.S. Department of Agriculture investigators discovered that Gambian giant rats from Ghana were housed with prairie dogs in Illinois. An African shipment of about 800 exotic mammals, including the Gambian rats that were imported into Texas, was the likely source of monkeypox, they concluded. The CDC and the Food and Drug Administration have prohibited the importation and sale of prairie dogs and six rodents from Africa. Some infected prairie dogs may have been sold at "swap meets" in Indiana, Illinois, Ohio, and Wisconsin, and records aren’t available to identify all the buyers, the CDC reported.

"One prairie dog has been associated with more than half the cases in our state, surely a supershedder if ever there was one," remarked Davis.

Globalization brings new diseases

The emergence of new diseases seems to be on the rise, as the nation copes with West Nile virus, SARS, and monkeypox. In part, that’s because bioterrorism preparedness has heightened our ability to detect outbreaks, CDC deputy director David Fleming, MD, said in a briefing. But he also noted, "We are living in a world that’s increasingly globalized. We can expect this to become more frequent rather than less."

Sometimes the microbe that threatens health care workers is known but uncommon. At Beth Israel Medical Center-Kings Highway Division, a delay in recognizing scabies in two patients led to an outbreak among health care workers. About 240 health care workers were referred to employee health, where they received prophylactic treatment. Twenty-seven reported an itchy rash, and eight cases were confirmed as scabies.

The first case, a cancer patient, came into the emergency department in respiratory distress. Physicians diagnosed her rash as a fungal infection because she was immunocompromised from chemotherapy. It was actually Norwegian scabies.

In the second case, a nursing home patient had a small rash on his arm that began to spread to his chest, arms, and groin.

The hospital now has a heightened awareness and a greater suspicion for unusual symptoms, says infection control practitioner Alexis Raimondi, MS, C, CIC. If someone comes into the emergency department with a rash, clinicians conduct an assessment, and if necessary, call in a dermatologist and increase infection control precautions. For example, health care workers exposed to the patient would wear long-sleeved gowns in addition to gloves.

"One of the nurses in the emergency room that took care of this [scabies] patient was itching and developed this rash on her arm," she says. "You could actually see where the glove line stopped. Above the glove line, she was developing little red pimples."

Getting a detailed history from patients is essential, says Raimondi. A history of potential exposure has been a key aspect of the case definition for SARS and monkeypox.

Raimondi also has focused on education about infection control, including the basics, such as hand hygiene. Several months after the outbreak of scabies, the hospital ruled out SARS in two patients. The episodes have created a greater vigilance for infection control practices.

"A lot of the staff are carrying the [alcohol-based] gels with them," says Raimondi. "You see them washing their hands more frequently."


1. Melski J, Reed K, Stratman E, et al. Multistate outbreak of monkeypox — Illinois, Indiana, and Wisconsin, 2003. MMWR 2003; 52:537-540.

2. Raimondi A, Koll B, Raucher B, et al. Scabies outbreak among healthcare workers. Poster presentation at the annual conference of the Association for Professionals in Infection Control and Epidemiology. San Antonio; June 8-12, 2003.

3. Langkop CW, Austin C, Dworkin M, et al. Update: Multistate outbreak of monkeypox — Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin, 2003. MMWR 2003; 52:561-564.

4. Centers for Disease Control and Prevention. Interim infection control and exposure management guidance in the health-care and community setting for patients with possible monkeypox virus infection. June 9, 2003.