RESEARCH Hansen Disease among Micronesian and Marshallese Persons Living in the United States Patricia Woodall, David Scollard, and Latha Rajan An increasing proportion of Hansen disease cases in the United States occurs among migrants from the Micronesian region, where leprosy prevalence is high. We abstracted surveillance and clinical records of the National Hansen’s Disease Program to determine geographic, demographic, and clinical patterns. Since 2004, 13% of US cases have occurred in this migrant population. Although Hawaii reported the most cases, reports have increased in the central and southern states. Multibacillary disease in men predominates on the US mainland. Of 49 patients for whom clinical data were available, 37 (75%) had leprosy reaction, neuropathy, or other complications; 17 (37%) of 46 completed treatment. Comparison of data from the US mainland with Hawaii and country of origin suggests under- detection of cases in pediatric and female patients and with paucibacillary disease in the United States. Increased case ﬁnding and management, and avoidance of leprosy-labeled stigma, is needed for this population. Arespectively, in 2007, the small Paciﬁc Island nations t 11 cases per 10,000 population and 8 per 10,000, of the Republic of the Marshall Islands and the Federated States of Micronesia have the highest prevalence of Hansen disease (HD), i.e., leprosy, in the world and have made little progress in the past decade toward the World Health Organization (WHO) leprosy elimination target of <1 per 10,000 (1,2). During the ﬁrst quarter of 2010, 33 new cases were detected among the 54,000 residents of the Marshall Islands (3). HD has been present in the United States for more than a century; the number of patients has remained relatively Author afﬁliations: Tulane University, New Orleans, Lousiana, USA (P. Woodall, L. Rajan); and National Hansen’s Disease Program, Baton Rouge, Louisiana, USA (D. Scollard) DOI: 10.3201/eid1707.102036 constant at 150–200 per year (4).The US National Hansen’s Disease Program (NHDP) has noted an increasing number of cases among US-resident Marshall Islanders and Micronesians, including several persons with advanced disease. In 1996, the Hawaii HD program reported a cluster involving 16 (5%) of 321 persons screened from a Marshallese migrant community (5,6). In 2002, the US Army noted 3 cases in 1 month in soldiers from this region (7). The recent reporting of multiple cases among the Marshallese community in northwestern Arkansas (Centers for Disease Control and Prevention, unpub. data, 2006) has drawn attention in a region unaccustomed to leprosy, with its stigmatizing historical connotations (8,9). Under the terms of the Compacts of Free Association (the legal documents governing the relationships between the United States, Federated States of Micronesia, and the Republic of the Marshall Islands), citizens of this former US Trust Territory of the Paciﬁc Islands are not subject to usual immigration requirements but may freely enter, reside, and work in the United States for as long as they wish. They hold a unique legal status, are not classiﬁed as immigrants, and maintain their country-of-origin citizenship. Transportation data indicate net emigration of an average of 952 Marshallese and 1,443 Micronesians annually, with a total of 38,325 emigrants for 1991–2006; almost all of these persons are thought to have immigrated to the United States and its territories (10). The actual distribution of this population within the United States is unknown; a speciﬁc category included in the 2010 US Census should provide this information. As economic and climatologic pressure drive increasing emigration from this HD-endemic former US Trust Territory, the US HD case load is expected to continue to increase, worsening health disparities and requiring increased program and local resources, although this increased case load is unlikely to create a public health 1202 Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 17, No. 7, July 2011