Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo (PNAS, abstract, edited)


[Source: Proc Natl Acad Sci USA, full text: <cite cite="http://www.pnas.org/content/107/37/16262.short?rss=1">Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo ? PNAS</cite>. Abstract, edited.]

Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo

Anne W. Rimoin a,b,1, Prime M. Mulembakani c, Sara C. Johnston d, James O. Lloyd Smith b,e, Neville K. Kisalu f, Timothee L. Kinkela c, Seth Blumberg b,e, Henri A. Thomassen g, Brian L. Pike h, Joseph N. Fair h, Nathan D. Wolfe h, Robert L. Shongo i, Barney S. Graham j, Pierre Formenty k, Emile Okitolonda c, Lisa E. Hensley d, Hermann Meyer l, Linda L. Wright m, and Jean-Jacques Muyembe n

Author Affiliations
a) University of California, Los Angeles School of Public Health, Los Angeles, CA 90095;
b) Fogarty International Center, National Institutes of Health, Bethesda, MD 20892;
c) Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo;
d) US Army Research Institute for Infectious Diseases, Frederick, MD 21702;
e) Departments of Ecology and Evolutionary Biology and
f) Microbiology, University of California, Los Angeles, CA 90095;
g) Center for Tropical Research, Institute of the Environment, University of California, Los Angeles, CA 90095;
h) Global Viral Forecasting Initiative, San Francisco, CA 94105;
i) Ministry of Health, BP 9030 Kinshasa, Democratic Republic of Congo;
j) Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892;
k) Department of Global Alert and Response, World Health Organization, 1211 Geneva 27, Switzerland;
l) Bundeswehr Institute of Microbiology, D-80937 Munich, Germany;
m) Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892; and
n) National Institute of Biomedical Research, BP 1197 Kinshasa, Democratic Republic of Congo

Edited* by Bernard Moss, National Institutes of Health, Bethesda, MD, and approved July 26, 2010 (received for review April 28, 2010)


Abstract

Studies on the burden of human monkeypox in the Democratic Republic of the Congo (DRC) were last conducted from 1981 to 1986. Since then, the population that is immunologically na?ve to orthopoxviruses has increased significantly due to cessation of mass smallpox vaccination campaigns. To assess the current risk of infection, we analyzed human monkeypox incidence trends in a monkeypox-enzootic region. Active, population-based surveillance was conducted in nine health zones in central DRC. Epidemiologic data and biological samples were obtained from suspected cases. Cumulative incidence (per 10,000 population) and major determinants of infection were compared with data from active surveillance in similar regions from 1981 to 1986. Between November 2005 and November 2007, 760 laboratory-confirmed human monkeypox cases were identified in participating health zones. The average annual cumulative incidence across zones was 5.53 per 10,000 (2.18?14.42). Factors associated with increased risk of infection included: living in forested areas, male gender, age < 15, and no prior smallpox vaccination. Vaccinated persons had a 5.2-fold lower risk of monkeypox than unvaccinated persons (0.78 vs. 4.05 per 10,000). Comparison of active surveillance data in the same health zone from the 1980s (0.72 per 10,000) and 2006?07 (14.42 per 10,000) suggests a 20-fold increase in human monkeypox incidence. Thirty years after mass smallpox vaccination campaigns ceased, human monkeypox incidence has dramatically increased in rural DRC. Improved surveillance and epidemiological analysis is needed to better assess the public health burden and develop strategies for reducing the risk of wider spread of infection.

* active surveillance
* orthopoxvirus
* zoonosis
* eradication

Footnotes
To whom correspondence should be addressed. E-mail: arimoin@ucla.edu.

Author contributions:
A.W.R., E.O., L.E.H., and J.-J.M. designed research; A.W.R., P.M.M., N.K.K., T.L.K, B.L.P., R.L.S., E.O., and J.-J.M. conducted field research activities; S.C.J., L.E.H., and H.M. conducted laboratory analysis; A.W.R., P.M.M., J.O.L.S., S.B., H.A.Y., and J.N.F. analyzed data; and A.W.R., N.D.W., P.F., and L.L.W. wrote the paper.

The authors declare no conflict of interest.

This Direct Submission article had a prearranged editor.

This article contains supporting information online at https://www.pnas.org/lookup/suppl/do...DCSupplemental.

Freely available online through the PNAS open access option.
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