December 7, 2005

Monkeypox often affects lymph nodes

NEW YORK (Reuters Health) - About three quarters of
patients with monkeypox have affected lymph nodes, a condition
that is rare in cases of smallpox or chicken pox, investigators
report in two articles in the journal Clinical Infectious
Diseases. Other common features of monkeypox, in addition to
rash and fever, include chills, sore throat, headache and
muscle pain.

Considered a possible agent of bioterrorism, it is
important to recognize signs and symptoms of monkeypox and to
differentiate it from other pox virus infections, research
teams led by Dr. Matthew J. Kuehnert and Dr. Aysegul Nalca
point out.

Kuehnert, from the Centers for Disease Control and
Prevention in Atlanta, and his colleagues analyzed records of
34 patients who were treated for monkeypox during an outbreak
in the US in 2003. The primary source of the infection was
traced to pet prairie dogs that had been housed with imported
rodents from Ghana.

Most patients reported that rash, fever, chills, and lymph
node swelling were the first symptoms to appear. Abnormal
laboratory findings included disturbances in liver tests, high
white blood cell counts, and low platelet levels.

In contrast to what is seen in cases of chickenpox, none of
those with monkeypox experienced excessive clotting throughout
the body and there were no deaths. However, nine patients were
hospitalized. In addition to the common symptoms, those
hospitalized were also likely to experience mouth sores,
difficulty swallowing, nausea and vomiting.

In the second report, Nalca, from the United States Army
Medical Research Institute of Infectious Diseases in Fort
Detrick, Maryland, and colleagues point out that laboratory
confirmation of monkeypox is required for a definitive

Smallpox vaccination is believed to be protective against
monkeypox virus. The CDC recommends vaccination for those who
may be exposed to monkeypox virus, up to 14 days after
exposure. Patients should be isolated until scabs fall off and
throat swab results are negative.

Nalca's team notes that the antiviral drug cidofovir is
effective in treating the infection in laboratory animals.
However, they add, "the risk of drug therapy must be examined
and weighed against the severity of poxvirus disease."

SOURCE: Clinical Infectious Diseases, December 15, 2005.