BOX 3-3
Recent Emergence of Monkeypox in the United States

On April 9, 2003, a shipment of 762 exotic rodents originating in Accra, Ghana, reached the United States. That shipment contained giant Gambian pouched rats (50 animals), rope squirrels (53), brushtail porcupines (2), tree squirrels (47), striped mice (100), and dormice (510). Accompanying these animals to Texas was an unexpected virus that eventually found its way into at least two other animal species in the United States (prairie dogs and humans) and spread to at least six other states. That unexpected agent, previously unseen in the United States, was a member of the orthopoxvirus group known as monkeypox (CDC, 2003b). It brought a scare to a public health and homeland security infrastructure, already in a state of heightened awareness for smallpox, and challenged the ability to address an emergent health threat in the United States that did not conveniently fall under the domain of any single federal agency.

In mid-May 2003, the first human cases of a febrile vesicular rash in the United States were examined by physicians in Illinois and Wisconsin. By June 10, a total of 53 cases were being investigated, 51 of which reported contact with a companion animal prairie dog. The Marshfield Clinic in Marshfield, Wisconsin, isolated and identified a virus from vesicular lesions of a human patient and from lymph nodes of the patient’s companion animal prairie dog. That virus, when examined by electron microscopy, resembled a poxvirus. The U.S. Centers for Disease Control and Prevention (CDC) subsequently identified it as monkeypox (CDC, 2003b). Spread of this poxvirus had peaked by early June, but in total over 70 cases from six states—Illinois, Wisconsin, Indiana, Kansas, Missouri, and Ohio—were reported over an approximately 3-month period. In Indiana, 28 children were exposed to a companion animal prairie dog, and seven became ill following this exposure (Langkop et al., 2003).

How did this virus make its way from exotic rodents in Ghana to a classroom in the heartland of the United States? Did it cause clinical signs in animals? Knowing that rodents in Africa carry monkeypox, why were these animals allowed into the United States, or at least not tested for the virus before entry? Who had responsibility for surveillance, identification, and response to this foreign zoonotic agent in exotic companion animals? These were some questions the committee asked while studying the monkeypox outbreak.

the monkeypox, which were distributed to eight states through “swap meets” where exotic animal aficionados gather to trade specimens.

Poor or no sales records are kept at swap meets, all of which complicated efforts to trace back and trace forward animals from the original



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