Hepatite B em Roraima : influência das migrações passadas e contemporâneas

Abstract

Human society is stricken by several infectious diseases, among them the hepatitis B. Hepatitis B Virus (HBV) has great genetic diversity, divided in 10 genotypes associated to different population according to its molecular phylogeny. In Brazil, it is estimated that about 0.52% of the population is living with the chronic for of the disease. This data is translated to an average detection rate of 6.6 cases per 100.000 inhabitants in 2019. Roraima state, north region, showed a detection rate of 28.9 cases per 100.000 inhabitants in the same year, rising the disease’s endemicity in the region. The state also has vast human diversity due to migrations flux. Internal migration flux that date from its formation to its consolidation. Also, external flux, more current, related to Haiti, Cuba and, mostly, Venezuela. Thus, the objective of this research was to characterize the origin of Hepatitis B virus genotypes by molecular phylogeny and analyze the effect of contemporary migrations in the epidemiological profile of the disease between 2013 and 2019. The study population was comprised of chronic HBV carriers that filled a form and provided a sample of blood after informed consent. Epidemiological data were compared as minor migratory flux period (2013-2015) and major migratory flux period (2017-2019). This data was analyzed through statistical tools. The blood sample was submitted to DNA extraction in order to amplify the viral gene S that was sequenced. The obtained sequences were used to elaborate phylogenetic trees using the bayesian and neighbor-joining methods. The results concluded that the period with minor increase in population there was a higher frequency among men (55%). Whilst in the period with major increase, women were more frequent (51%), group that showed significant increase between the studied periods. There was a significant increase in the age range from 36 to 45 years in women. Education appeared to change, as there was an increase of people with a complete high school, but there was a decrease in people with incomplete middle school. Boa Vista remained as the city with most cases registered. Other variables like race, marital and vaccinal status did not show significant changes. From the 40 sequenced samples, the phylogeny confirmed its identities as subgenotypes A1 (52,5%), D3 (17,5%), F2a (17,5%), F3 (7,5%), D4 (2,5%), A5 (2,5%) and E (2,5%), with the last two having their first appearance in Roraima. The tree’s topology from A1 subgenotype showed the existence of an African lineage that does not occur in the rest of Brazil. Guyana, Rio de Janeiro and Maranhão were the sources of strains with this subgenotype in Roraima. The neighor-joining tree’s topology showed the relation of the F2a subgenotype with Brazilian and Venezuelan samples. Subgenotype F3 was very likely introduced from Venezuela. In both trees, the multiple events of strain introduction are clear, which agree with the human diversity found in Roraima state. The sum of the results showed that the Hepatitis B epidemiologic profile did not change much between the periods of minor and major increase in population. However, the molecular analysis showed a big increase in viral diversity. The continuous vigilance of the epidemiologic profile of Hepatitis B and its phylogeography are essential to improve the target group of treatment and prevention campaigns.