Injecting reason.

Authors' reply

We appreciate the comments of Mary G Reynolds and colleagues regarding the 2003 US monkeypox outbreak. Our review states that a rabbit “was implicated as the source of primary infection in one US case”. This statement is based on an issue of the Morbidity and Mortality Weekly Report (MMWR) that reported, “One patient had contact with a rabbit (family Leporidae) that became ill after exposure to an ill prairie dog at a veterinary clinic”. Reynolds et al cite unpublished data to inform us that later testing of necropsy specimens from this rabbit showed no evidence of infection with the monkeypox virus. We welcome this clarification since the four subsequent MMWR updates on the US outbreak do not document this.3, 4, 5, 6 We do not agree with Reynolds and colleagues' suggestion that a particular MMWR update sufficiently clarified this issue for readers. That report indicated that prairie dog exposures were associated with the 35 confirmed cases of monkeypox in human beings; it did not indicate that prairie dog exposures were associated with all of the 71 reported human cases that comprised the outbreak. It simply states that “the majority” of all cases were exposed to prairie dogs, thereby leaving open the possibility that the earlier report implicating the rabbit was still accurate.

We recognise that in infectious disease outbreaks initial case counts are commonly revised because of updated case definitions and ongoing investigations. We have addressed the revised counts noted by Reynolds et al in a published letter.

We agree with Reynolds and colleagues that the full breadth of potential animal reservoirs for the monkeypox virus are poorly characterised and that the presence of non-rodent species in the contaminated African shipment may prove note worthy. We look forward to the publication of additional findings from their ongoing laboratory and epidemiologic research into this outbreak.

Finally, we would like to acknowledge the Armed Forces Institute of Pathology website (http://www.afip.org/Departments/infectious/mp/index.html), from which we identified figures 1 and 2 in our review.