Hepatitis A virus subgenotypes in Latvia, 2008-2021

Funding Information: This research was carried out in accordance with the Declaration of Helsinki, as revised in 2013 [40]. Ethics Committees of Riga Stradins University (Reference: 4/08.09.2018), Riga East University Hospital (Reference: ZD/08–06/01–19/210) and Centre for Disease Prevention and Control of Latvia (Reference:6.1–3/8) approved the study. HAV cases were not directly involved in this study. Only data extracted from notifiable disease surveillance systems were used. All identifiable personal information was removed for privacy protection and therefore no informed consent was required. Publisher Copyright: © 2023 The Author(s)BACKGROUND: In Latvia outbreaks of the HAV were observed between 2008 and early 2010 and again in 2017-2018. However, the risks of introducing and spreading infection still exist, as the virus spreads easily when personal hygiene is not followed. METHODS: To determine the spread of HAV subgenotypes in the territory of Latvia the VP1/P2A genomic region of HAV was amplified and sequenced for 259 case serum samples. The study carried out a molecular biological investigation and molecular epidemiological investigation. Demographic data (sex, age), disease data (hepatitis symptoms, hospitalization, vaccination) and epidemiology data (part of the outbreak, possible source of infection, recent travel) were collected. Based on the obtained sequences, the phylogenetic tree was built and analyzed for the homology and belonging to different isolated HAV clusters from other countries. RESULTS: From the obtained data, it was concluded that HAV subgenotype IA had 13 clusters and 12 sporadic cases, HAV subgenotype IB had eight clusters and 11 sporadic cases, HAV subgenotype IIIA had one cluster and nine sporadic cases. It was found that the sources of infection among the investigated cases were different, they were mostly associated with contact with a patient with HAV, travel, as well as between persons who inject drugs and men who have sex with men, and the prevalence of HAV similar sequences was observed in different years. It was concluded that patients with HAV subgenotype IA had the longest hospitalization duration and averaged 9.3 days, while patients with subgenotype IB - 7.3 days, subgenotype IIIA - 7.7 days. Analyzing the data on vaccination, it was found that mostly all were not vaccinated or had an unknown vaccination status. CONCLUSIONS: All of this has led to the conclusion that the application of molecular biological methods of the HAV and a careful analysis of epidemiological data can help to better understand the ways of spreading the infection, investigate local outbreaks, detect cases of imported infection and track the recirculation of the virus.Peer reviewe

Interleukin 28B Gene Polymorphism and Association with Chronic Hepatitis C Therapy Results in Latvia

Introduction. With the standard treatment of chronic hepatitis C, sustained virological response (SVR) can be achieved only in half of all patients. Interleukin-28B appears to be involved in the control of HCV infection, and the genetic polymorphism of the encoding IL-28B gene may determine the efficacy of clearance of HCV. The aim of this paper was to detect IL-28B gene polymorphism in Latvia and to analyze therapy results. This is the first study on IL-28B gene polymorphism in Latvia. Material and Methods. There were 159 chronic viral hepatitis C patients included in the study. In order to detect IL-28B gene polymorphism, we used molecular biology techniques and methods: classical DNA separation, amplification by PCR, and standard sequencing. Genotype was defined as CC, CT, TC, or TT type. 142 patients were treated with the standard of care treatment. Results were analyzed according to IL-28B polymorphism. Results. There were 53 patients (33%) with CC genotype, 84 patients (53%) with CT/TC genotype, and 22 patients (14%) with TT genotype. 34 patients (74%) in CC genotype subgroup achieved SVR versus 50 patients (52%) in non-CC subgroups. In patients with genotype 1, SVR was achieved in 16 patients (84%) in CC subgroup versus 30 patients (47.6%) in non-CC subgroups, P = 0.007. Conclusions. The most common genotype of IL28B in Latvia is CT/TC, with an incidence of 53%. Patients with CC genotype achieved SVR more often than CT or TT subgroups. IL28B gene polymorphism therefore is a strong predictor of treatment result