Work

HIV-1 Genetic Diversity in Antenatal Cohort, Canada

Year: 2005

Type: article

Abstract: We studied HIV genetic diversity in a cohort of 127 pregnant, HIV-infected women who received prenatal care at Sainte-Justine Hospital in Montreal, Canada, between 1999 and 2003.Clade assignments were derived by phylogenetic analysis of amplified pol sequences.Genotyping was successful in 103 of 127 women, 59 (57.3%) of whom were infected with clade B HIV-1, and 44 (42.7%) with nonclade B viruses, including subtypes A, C, D, F, G, and H. Four sequences remained unassigned.Forty-three of 44 women infected with non-clade B viruses were newcomers from sub-Saharan Africa, and subtype identity was consistent with those circulating in their countries of origin.These results highlight the epidemiologic importance of non-B HIV-1 in antenatal populations in a large North American urban center, underscore the influence of population movements on clade intermixing, and identify a group of patients who could be targeted for surveillance and drug therapy followup. H IV-1 exhibits considerable genetic diversity resultingfrom the high mutation rate of reverse transcriptase, high viral turnover, viral genomic recombination, and immune and therapeutic selection pressures (1-3).This diversity is a challenge for viral load determination, drug resistance testing, and AIDS vaccine development (1,4-6).Three phylogenetic groups of HIV-1, main (M), outlier (O), non-M, non-O (N), are recognized (2,7).Most HIV-1 infections are caused by group M viruses that comprise 9 clades (A-D, F-H, J, and K) and >13 intersubtype recombinants known as circulating recombinant forms (CRFs) (8).Clade B is most common in North America, Europe, and Australia.However, in the last decade, prevalence of infection with nonclade B viruses has increased in France, Belgium, Spain, and Switzerland (9-12), in large part after migration from or international travel into HIV-endemic areas (13).Nonclade B viruses also circulate in Cuba ( 14) and the United States (15,16).We measured HIV-1 subtype diversity in a multiethnic cohort of pregnant, HIV-infected women to determine whether nonclade B HIV-1 is emerging in Canada after population movement, and whether antenatal cohorts are suitable sentinel sites to monitor the introduction of nonclade B viruses into Canada. Patients and Methods PatientsOne hundred twenty-seven HIV-infected women receiving prenatal care at Centre Maternel et Infantile sur le SIDA, Sainte-Justine Hospital, Montreal, from October 1999 to September 2003 were included in the study.Inclusion criteria were 1) age ≥18 years, 2) a request for prenatal care, 3) positive HIV-1 serologic results, and 4) informed consent.Standardized clinical followup, including antiretroviral (ARV) prophylaxis and treatment, was provided to all women and their children.This cohort study was conducted according to the guidelines of the Ethics Review Board of Sainte-Justine Hospital.

Source: Emerging infectious diseases

DOI: 10.3201/eid1108.040877