Volume 12, Number 12—December 2006
Perspective
Qualitative Assessment of Risk for Monkeypox Associated with Domestic Trade in Certain Animal Species, United States
Susan M. Bernard*
and Steven A. Anderson*
and Steven A. Anderson*Table 2
Variables considered in characterizing risk for human monkeypox cases and the degree of uncertainty associated with these variables
| Variable | Degree of uncertainty |
|---|---|
| Animal host and carrier species | High—some, but not all, host species identified |
| Proportion of probable host or carrier species infected with virus | High—need to assume absent data that all animals within known or probable carrier species are infected |
| Proportion of animals exposed during US 2003 outbreak infected with virus | High—need to assume that all exposed animals are infected |
| Susceptibility of naive animals to infection | High—but experience in United States and Africa suggests several species and orders can be infected with monkeypox virus |
| Latency in nonhuman species | High |
| Duration of infection or infectiousness in nonhuman species | High |
| Seasonality of disease | High—some indication of peak monkeypox cases in humans in July and August in African outbreaks, which may be associated with human behavior rather than characteristics of virus or host animals |
| Incubation in nonhuman species | High |
| Infection rates in exposed nonhuman species | High |
| Proportion of infected animals (of different species) that shed virus | High |
| Mode(s) of transmission across species and to humans | High—but evidence of mucocutaneous and respiratory transmission pathways |
| Attack rates among humans exposed to infected animals | High |
| Secondary attack rates among humans | High—secondary attack rates seem to be increasing in monkeypox-endemic areas due to increasing susceptibility of exposed populations, and historical data indicating low risk for human transmission may be unreliable |
| Fatality rates in nonhuman species | High |
