The Role of Migration and Domestic Transmission in the Spread of HIV-1 Non-B Subtypes in Switzerland

• Published in: The Journal of infectious diseases 2011-10, Vol.204 (7), p.1095-1103
• Main Authors: von Wyl, Viktor, Kouyos, Roger D., Yerly, Sabine, Böni, Jürg, Shah, Cyril, Bürgisser, Philippe, Klimkait, Thomas, Weber, Rainer, Hirschel, Bernard, Cavassini, Matthias, Staehelin, Cornelia, Battegay, Manuel, Vernazza, Pietro L., Bernasconi, Enos, Ledergerber, Bruno, Bonhoeffer, Sebastian, Günthard, Huldrych F.
• Format: Article
• Language: English
• Subjects: African Continental Ancestry Group - statistics & numerical data; Asian Continental Ancestry Group - statistics & numerical data; Biological and medical sciences; Cluster Analysis; Disease transmission; Emigration and Immigration; Epidemics; Ethnicity; European Continental Ancestry Group - statistics & numerical data; Female; Fundamental and applied biological sciences. Psychology; Gene Products, pol - metabolism; Heterosexuality - statistics & numerical data; HIV; HIV 1; HIV Infections - ethnology; HIV Infections - genetics; HIV Infections - transmission; HIV-1 - genetics; HIV-1 - metabolism; HIV/AIDS; Homosexuality, Male - statistics & numerical data; Human immunodeficiency virus 1; Humans; Infections; Infectious diseases; Likelihood Functions; Logistic Models; Male; Medical sciences; Men; Microbiology; Miscellaneous; Molecular Sequence Data; Phylogenetics; Prevalence; Switzerland - epidemiology; Virology; White people
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jir491

Background. By analyzing human immunodeficiency virus type 1 (HIV-1 ) pol sequences from the Swiss HIV Cohort Study (SHCS), we explored whether the prevalence of non-B subtypes reflects domestic transmission or migration patterns. Methods. Swiss non-B sequences and sequences collected abroad were pooled to construct maximum likelihood trees, which were analyzed for Swiss-specific subepidemics, (subtrees including ≥ 80% Swiss sequences, bootstrap > 70%; macroscale analysis) or evidence for domestic transmission (sequence pairs with genetic distance < 1.5%, bootstrap ≥ 98%; microscale analysis). Results. Of 8287 SHCS participants, 1732 (21%) were infected with non-B subtypes, of which A (n = 328), 21% (A), 16% (C), 24% (CRF01_ AE), and 28% (CRF02_ AG) belonged to Swiss-specific subepidemics. The microscale analysis identified 26 possible transmission pairs: 3 (12%) including only homosexual Swiss men of white ethnicity; 3 (12%) including homosexual white men from Switzerland and partners from foreign countries; and 10 (38%) involving heterosexual white Swiss men and females of different nationality and predominantly nonwhite ethnicity. Conclusions. Of all non-B infections diagnosed in Switzerland, < 25% could be prevented by domestic interventions. Awareness should be raised among immigrants and Swiss individuals with partners from high prevalence countries to contain the spread of non-B subtypes.