Update of the global distribution of human gammaherpesvirus 8 genotypes

Abstract

Human gammaherpesvirus 8 (HHV-8) consists of six major clades (A-F) based on the genetic sequence of the open reading frame (ORF)-K1. There are a few conflicting reports regarding the global distribution of the different HHV-8 genotypes. This study aimed to determine the global distribution of the different HHV-8 genotypes based on phylogenetic analysis of the ORF-K1 coding region using sequences published in the GenBank during 1997-2020 and construct a phylogenetic tree using the maximum likelihood algorithm with the GTR + I + G nucleotide substitution model. A total of 550 sequences from 38 countries/origins were analysed in this study. Genotypes A and C had similar global distributions and were prevalent in Africa and Europe. Genotype B was prevalent in Africa. Of the rare genotypes, genotype D was reported in East Asia and Oceania and genotype E in South America, while genotype F was prevalent in Africa. The highest genotypic diversity was reported in the American continent, with Brazil housing five HHV-8 genotypes (A, B, C, E, and F). In this study, we present update of the global distribution of HHV-8 genotypes, providing a basis for future epidemiological and evolutionary studies of HHV-8.

Figure 1

Number of HHV-8 ORF-K1 coding region sequences published per country/origin. Sequences were collected from GenBank. (CAR, Central African Republic; COD, Democratic Republic of the Congo).

Figure 2

Phylogenetic analysis of multiple HHV-8 sequences based on the sequence of ORF-K1 coding region using the maximum-likelihood method. GenBank accession numbers for all sequences are presented in the supplementary material 1. The colours indicating the different genotypes and continents are shown in the key for the figure. The colour light blue refers to the subgenotype A5. The sequences are indicated by the genotype followed by country or origin (CAR, Central African Republic; COD, Democratic Republic of the Congo), and accession number. The filled circle symbol indicates location of all Brazilian sequences. In this phylogenetic tree are indicated all the values at internal nodes likelihood-ratio test value for the branch. The tree is rooted in the midpoint and was viewed using iToL.

Figure 3

Global distribution of HHV-8 genotypes. The six world maps demonstrate the distribution of each HHV-8 genotypes (A - F). The genotypes and continents are indicated in the figure. Countries forming a continent are shaded in the same colour. The size of the circles is proportional to the number of HHV-8 ORF-K1 coding region sequences belonging to a particular origin analysed in this study. All sequences collected from GenBank.

Figure 3

Global distribution of HHV-8 genotypes. The six world maps demonstrate the distribution of each HHV-8 genotypes (A - F). The genotypes and continents are indicated in the figure. Countries forming a continent are shaded in the same colour. The size of the circles is proportional to the number of HHV-8 ORF-K1 coding region sequences belonging to a particular origin analysed in this study. All sequences collected from GenBank.

Figure 4

The HHV-8 genotypic diversity per country/origin. The pie charts indicate the proportion of occurrence of the different HHV-8 genotypes in the respective countries/origins. The genotypes and continents are indicated in the figure. Countries from the same region are shaded in the same colour on the world map. These distributions of HHV-8 genotypes were based on sequences analysed in this study.