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The evolutionary and transmission characteristic of HIV-1 CRF07_BC in Nanjing, Jiangsu
Wei Li1, Xiaoshan Li2, Yan He1
1Key Laboratory of Environmental Medicine Engineering, Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Ministry of Education, Nanjing, Jiangsu, China.
Insights
Human Immunodeficiency Virus type 1 CRF07_BC in Nanjing, China, primarily affects men who have sex with men and was introduced over 20 years ago. This subtype shows a high evolutionary rate and significant transmission clusters within the population.
Area of Science:
- Epidemiology
- Virology
- Public Health
Background:
- The Human Immunodeficiency Virus type 1 (HIV-1) CRF07_BC subtype is a significant concern in China.
- Understanding its epidemiological and evolutionary dynamics is crucial for effective control strategies.
Purpose of the Study:
- To investigate the epidemiology, evolutionary, and transmission characteristics of HIV-1 CRF07_BC in Nanjing, China.
- To determine the origins and spread of this subtype within the region.
Main Methods:
- Recruitment of 159 HIV-1 CRF07_BC infected patients.
- Utilized DNA sequencing, phylogenetic analysis, and molecular transmission cluster analysis.
- Applied maximum likelihood phylogenetic analyses and a relaxed exponential clock model.
Main Results:
- HIV-1 CRF07_BC in Nanjing predominantly affects males (95.6%), with men who have sex with men being the main transmission route (76.7%).
- Phylogenetic analysis revealed two lineages, with 67.3% of sequences forming 11 distinct transmission clusters.
- The most recent common ancestor was estimated to be around 1998.71, with a mean evolutionary rate of 2.38 × 10⁻³ per site per year.
- The subtype was introduced into Nanjing over 20 years ago from Yunnan and has become predominant with an increased evolutionary rate.
Conclusions:
- HIV-1 CRF07_BC has established a significant presence in Nanjing, China, with distinct epidemiological and transmission patterns.
- The subtype exhibits a relatively high evolutionary rate, suggesting ongoing adaptation and spread.
- Findings highlight the importance of targeted prevention and control efforts for key populations in Nanjing.
Abstract:
To understand the epidemiology, evolutionary and transmission characteristics of HIV-1 CRF07_BC in Nanjing, China. One hundred and fifty-nine patients with HIV-1 CRF07_BC were recruited. DNA sequencing, phylogenetic analysis, and molecular transmission cluster analysis were conducted to determine the molecular epidemiology and evolutionary characteristics. Of these HIV-1-infected patients, 95.6% were male, and men who sex with men (76.7%) were the main transmission route. Only 34.0% of these cases were born in Nanjing, and most of them (64.8%) reported having multiple sex partners in the last 6 months. The maximum likelihood phylogenetic analyses of HIV-1 CRF07_BC revealed two lineages. Overall, 67.3% of Nanjing sequences were connected to at least one other individual distributed in 11 clusters, and the average degree was 21.2 with range (1-178). The clustered patients were more likely to be male. The time to a most recent common ancestor for the early HIV-1 CRF07_BC circulating in Nanjing was estimated to be 1998.71[1997.36-2001.07]. The mean estimated evolutionary rate for the epidemic cluster was slightly lower at 2.38[2.12-2.65] × 10-3 per site per year with the relaxed exponential clock model. HIV-1 CRF07_BC was transmitted into Nanjing more than 20 years ago from Yunnan and has become one of the most predominant subtypes with a higher evolutionary rate than before.
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