ABSTRACT
Organ transplantation is the most effective treatment for various types of end-stage diseases. To resolve the problem of donor shortage in organ transplantation, the possibility of xenotransplantation has been gradually explored by surgeons. Pig is one of the common donor sources for xenotransplantation. As a bridge between two species, the viruses carried by pig organs may be transmitted between species and cause the risk of zoonosis. Porcine endogenous retrovirus (PERV) is integrated into the genome, which is a category of retrovirus featuring cross-species transmission. In this article, the influencing factors of transmission characteristics of PERV, the transmission risk of PERV and its recombinant virus, and the detection and transmission risk assessment of PERV in xenotransplantation test were reviewed, aiming to provide reference for alleviating severe shortage of donor organs and driving the advancement of xenotransplantation technologies.
ABSTRACT
Objective:To understand the molecular transmission characteristics of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome(AIDS) patients in the mountainous area of southwest Zhejiang Province(Lishui city).Methods:A total of 147 blood samples were collected from newly-diagnosed HIV-1 infected who received no antiviral therapy, and pol gene was amplified, followed by sequencing. MEGA6.0 software was used to construct phylogenetic tree and determine gene subtypes. HIVDB online was used to analyze drug resistance mutation, then the pairwise genetic distance(GD) was calculated and the opitimal threshold of GD was selected, finally the molecular transmission network was constructed by Cytoscape3.7.0 software. Chi-square or Fisher′s exact probability method was used for statistical analysis. Results:A total of 134 sequences were obtained successfully, and nine subtypes were detected. The dominant subtypes were CRF08_BC (34.33%, 46/134), CRF01_AE (29.85%, 40/134) and CRF07_BC (23.88%, 32/134). It also found that age, registered residence, education level and transmission route had significant differences in distribution of subtypes ( P<0.05). Nineteen drug resistance individuals were found, and the total drug resistance rate was 14.18% (19/134). The HIV-1 molecular transmission network was plotted based on 1.2% GD threshold. A total of 15 transmission clusters (cluster size ranging from 2 to 29) were found. The network access rate was 49.25% (66/134), mainly including male (75.76%, 50/66), heterosexual (81.82%, 54/66) and patientsrinfected with CRF08_ BC (50.00%, 33/66). A transmission cluster including two cases of female sex workers and seven cases of drug resistance was identified, in which the average age of the patients was 57.21 years old and the average degree value was 22.7, and the cases were mainly infected through heterosexual contact (96.55%, 28/29). The highest homology of the sequences in the cluster was in Yunnan. Conclusions:The HIV-1 subtypes were diverse in the mountainous area of southwest Zhejiang Province(Lishui city). Drug resistant transmission had reached a moderate epidemic level. There were molecular transmission clusters with the aggregation characteristics of elderly clients in specific regions. It was urgent to formulate and implement precise intervention strategies to curb the spread of HIV.
ABSTRACT
HIV molecular network is a recently reported method for studying the transmission characteristics of HIV-infected people. Countries have used this method to conduct a large number of researches on transmission relations, transmission hotspots and epidemic surveillance for the purpose of providing evidence for precise AIDS intervention and control. At present, there are three major methods for constructing molecular networks in the world, i.e. genetic distance method based on pairwise alignment, phylogenetic node support method, and joint parameter method based on the two methods. This paper reviews the progress of the three methods for constructing HIV molecular network to study the transmission characteristics of HIV-infected patients, in order to provide data support for the prevention and control of HIV. Since the emergence of the molecular network method, Beijing, Shanghai, Zhejiang, Sichuan and other provinces in China have reported relevant research results using molecular network analysis, which provided scientific data for further precise AIDS prevention and control. Recent international studies have also predicted that molecular network based transmission cluster detection is expected to become a new method to stop AIDS epidemic.
ABSTRACT
Objective@#Using field epidemiological investigation and molecular analysis to construct the molecular transmission network of human immunodeficiency virus/acquired immunodeficiency syndrome cases (HIV/AIDS) newly diagnosed in Huzhou in 2017, Zhejiang Province.@*Methods@#A total of 160 participants were obtained through a web-based system from Chinese Center for Disease Control and Prevention (CCDC) with the features of diagnosed in Huzhou in 2017 who also had been collected samples for the first follow-up. The basic information of demographic characteristics and risk factors was extracted from the website. RNA was extracted from plasma samples of untreated cases, followed by RT-PCR and nest-PCR for pol gene amplification, sequencing. Phylogenetic tree was constructed by MEGA software for HIV gene subtyping. TN93 model was used for calculating the distance between two sequences. Cytoscape software was used for drawing molecular transmission network. And then an epidemiological survey was conducted to cases in the primary cluster.@*Results@#A total of 138 sequenced individuals (86.3%) were acquired from 160 individuals. Among which, 123 (89.1%) were male. The highest proportion of subtype was CRF07_BC (60, 43.5%), followed by CRF01_AE (46, 33.3%), and with four cases of Unique Recombinant Form (URF, CRF01_AE and CRF07_BC) and one case of URF (subtype B and C). A total of 18 molecular clusters included 56 individuals (40.6%) were found in the transmission network under the optimal genetic distance threshold (1.0%). The clustering proportion of CRF07_BC (66.1%, 37 cases) was higher than that of CRF01_AE. There were 9 clusters formed among CRF07_BC, including 37 cases (accounting for 61.7%, 37/60). The primary transmission cluster contained 11 cases, among which 9 cases were transmitted by homosexual sex. The first time of the cases to have homosexual behavior is range from 2010 to 2016, whose media number (P25, P75) of partners was 6 (3.5, 8.5). Most of the cases come from Anhui Province and engaged in garment industry (5 cases), between which there were 8 cases used Blued software to seek for casual partners, 1 case seeking for casual partners in garden.@*Conclusion@#With CRF07_BC and CRF01_AE predominantly circulating, HIV genetic diversity had been noticed in this area. The primary cluster was consisted of high proportion of locally new infections, and a specific population aggregation in limited place existed.