The Role of Surinamese Migrants in the Transmission of Chlamydia trachomatis between Paramaribo, Suriname and Amsterdam, The Netherlands

The Netherlands. PLoS ONE 8(11): e77977. doi:10.1371/journal.pone.0077977 The Role of Surinamese Migrants in the Transmission of Chlamydia trachomatis between Paramaribo, Suriname and Amsterdam, The Netherlands Reinier J. M. Bom 0 Jannie J. van der Helm 0 Sylvia M. Bruisten 0 Antoon W. Gru nberg 0 Leslie O. A. Sabajo 0 Maarten F. Schim van der Loeff 0 Henry J. C. de Vries 0 0 1 Public Health Laboratory, Cluster Infectious Diseases, Public Health Service of Amsterdam , Amsterdam , The Netherlands , 2 Department of Research, Cluster Infectious Diseases, Public Health Service of Amsterdam , Amsterdam , The Netherlands , 3 STI Outpatient Clinic , Cluster Infectious Diseases , Public Health Service of Amsterdam , Amsterdam , The Netherlands , 4 Department of Experimental Virology, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands, 5 Lobi Foundation, Paramaribo , Suriname , 6 Dermatological Service, Ministry of Health , Paramaribo , Suriname , 7 Department of Dermatology, Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands, 8 Center for Infections and Immunity Amsterdam (CINIMA) , Academic Medical Center, University of Amsterdam , Amsterdam , The Netherlands , 9 Center for Infectious Disease Control, National Institute of Public Health and the Environment , Bilthoven , The Netherlands The large Surinamese migrant population in the Netherlands is a major risk group for urogenital Chlamydia trachomatis infection. Suriname, a former Dutch colony, also has a high prevalence of C. trachomatis. Surinamese migrants travel extensively between the Netherlands and Suriname. Our objective was to assess whether the Surinamese migrants in the Netherlands form a bridge population facilitating transmission of C. trachomatis between Suriname and the Netherlands. If so, joint prevention campaigns involving both countries might be required. Between March 2008 and July 2010, participants were recruited at clinics in Paramaribo, Suriname and in Amsterdam, the Netherlands. Participants were grouped as native Surinamese, native Dutch, Surinamese migrant, Dutch migrant, or Other, based on country of residence and country of birth of the participant and of their parents. Risk behavior, such as sexual mixing between ethnic groups, was recorded and C. trachomatis positive samples were typed through multilocus sequence typing (MLST). A minimum spanning tree of samples from 426 participants showed four MLST clusters. The MLST strain distribution of Surinamese migrants differed significantly from both the native Surinamese and Dutch populations, but was not an intermediate state between these two populations. Sexual mixing between the Surinamese migrants and the Dutch and Surinamese natives occurred frequently. Yet, the MLST cluster distribution did not differ significantly between participants who mixed and those who did not. Sexual mixing occurred between Surinamese migrants in Amsterdam and the native populations of Suriname and the Netherlands. These migrants, however, did not seem to form an effective bridge population for C. trachomatis transmission between the native populations. Although our data do not seem to justify the need for joint campaigns to reduce the transmission of C. trachomatis strains between both countries, intensified preventive campaigns to decrease the C. trachomatis burden are required, both in Suriname and in the Netherlands. - Competing Interests: The authors have received funding from a commercial source: AGIS healthcare insurance. This does not alter the authors adherence to all the PLOS ONE policies on sharing data and materials. . These authors contributed equally to this work. Chlamydia trachomatis infections occur endemically among the general population of the Netherlands, but most infections are found in defined risk groups, such as adolescents and men who have sex with men (MSM) [1]. In addition, some ethnic minority groups are affected disproportionally by C. trachomatis infections [2]. Migrants from Suriname constitute one of the largest ethnic minority groups in the Netherlands, and the highest prevalence of C. trachomatis has been reported in this population. In 2011, the C. trachomatis prevalence among clients of the Dutch sexually transmitted infection (STI) clinics was 18% for heterosexual Surinamese migrants compared with 11% for native Dutch heterosexuals [3]. Suriname is a former colony of the Netherlands in the Caribbean region. It is a multi-ethnic society consisting of Creoles, Maroons, Hindustani, Javanese, Chinese, Caucasians, and indigenous Amerindians, as well as a mixed race population. Although considered an upper middle-income country by World Bank standards, Suriname is an emerging economy in which reliable diagnostics to detect C. trachomatis infections and other STIs are still lacking for the majority of its inhabitants [4]. The prevalence of C. trachomatis infections is high; one study demonstrated around 10% prevalence in a low-risk population (clients of a birth control clinic) and 21% in a high-risk population (clients of an STI clinic) [5]. Since the independence of Suriname in 1975, a large proportion of the Surinamese population migrated to the Netherlands and today almost as many people of Surinamese origin live in the Netherlands as in Suriname itself. Amsterdam has the largest number of Surinamese inhabitants outside of Suriname. As a result, traveling between the two countries is common. A study in 2008 found that more than half of the population of Surinamese descent living in the Netherlands had visited friends and relatives in Suriname during the preceding five years [6]. Of these travelers, 9% reported unprotected sexual contact in both countries [2]. Discordant sexual mixing is defined as sex between partners from two different groups (e.g. with different age or ethnicity) [7]. A group characterized by a high degree of sexual mixing can act as a bridge population for STI transmission between seemingly unrelated groups. Surinamese migrants living in the Netherlands may thus be a bridge population for STI transmission between the native populations in Suriname and the Netherlands [6]. If this is the case, it has implications for the design of effective preventive measures to reduce STI transmission. Joint campaigns involving both countries and a focus on travelers might be needed to reduce overall STI prevalence and to increase the impact of prevention. We hypothesized that Surinamese migrants constitute a bridge population for the transmission of C. trachomatis between Suriname and the Netherlands. If this were the case, this would be reflected by: 1) A high degree of sexual mixing with native Surinamese and native Dutch partners, and 2) A distribution of C. trachomatis genotypes that is more similar to the native Surinamese or native Dutch population among the Surinamese migrants who report sexual mixing with the native Surinamese or native Dutch population (...truncated)