The prevalence of CRF55_01B among HIV-1 strain and its connection with traffic development in China

Abstract

CRF55_01B is a relatively "young" HIV strain. At present, we do not know much about its transmission characteristics in China. So, to describe the transmission characteristics of CRF55_01B strain among provinces and HIV infected people, and to analyze the reasons for its rapid epidemic in China, a total of 1237 subjects infected with CRF55_01B from 31 provinces spanning a period of 12 years from 2007 to 2018 were enrolled in this study. By constructing a molecular network and Bayesian correlation analysis, we found that CRF55_01B increased exponentially from 2005 to 2009 after its origin in Shenzhen, and increased rapidly after 2010. CRF55_01B began to spread to other provinces in 2007. After 2010, the strain showed a trend of rapid spread and epidemic from Guangdong-Shenzhen to other provinces in China. Guangdong, Shenzhen, Hunan, Beijing, Guangxi, Hubei, Jiangxi, Guizhou, Hebei, Anhui, Shanghai, Shandong, Henan, and Yunnan were the key provinces of CRF55_01B transmission. CRF55_01B, although originating from men who sex with men (MSM), was transmitted among heterosexuals in 2010. Males in heterosexuals played a crucial role in the transmission and diffusion of this strain. We also revealed that CRF55_01B might spread rapidly along with the rapid development of the Beijing-Guangzhou and Beijing-Kowloon railways. This study suggests that if we detect the spread of MSMs in time through molecular monitoring in the early stage of the epidemic, it can help us control the epidemic early and prevent its spread, which is of great significance to China's national prevention and control of HIV-1.

Keywords: CRF55_01B strain; HIV-1; epidemic history; molecular network; phylogeographic.

Figure 1.

Time-scaled phylogeographic history of CRF55_01B strain. Branch colours represent the most probable province of the parental node of each branch. The MCC trees and Bayesian Skygrid demographic reconstruction share a timeline. The dotted frame shows the period of rapid spread of CRF55_01B strain from 2005 to 2009.

Figure 2.

The roadmap of CRF55_01B strain propagating. The lines in the figure show the posterior probability ≥ 0.8. Lines opacity were 0.4. The Beijing-Guangzhou railway is shown in the picture. The red circles indicate the absolute and relative intensity of local CRF55_01B spread.

Figure 3.

The bar chart shows the input (in) and output (out) of CRF55_01B by regions and provinces. The map shows the provinces where CRF55_01B is most heavily propagated in the BSSVS analysis. The transmission relationships of provinces between BF ≥ 50 and posterior probability ≥ 0.8 are shown in the figure. Mean counts are the average counts from A to B calculated by the MCC trees. South China has very little inputs in the bar, but GD and SZ have a lot. This is because south China mean counts from other areas. GD and SZ import more because they spread more to each other.

Figure 4.

The bar chart shows the input (in) and output (out) of CRF55_01B by Risks, Risk-Sexs and Risk-Ages. The transmission relationships among different groups are depicted in the figure. The transmission relationships between BF ≥ 50 and posterior probability ≥ 0.8 were shown in the figure. The thickness of the arrows in the figure indicates the magnitude of BF and the posterior probability.

Figure 5.

Correlation between the dissemination of CRF55_01B and the Beijing-Guangzhou/Beijing-Kowloon railways.