Abstract：
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.
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.
摘要：
背景：在拉脱维亚，2008年至2010年初以及2017年至2018年再次爆发了HAV。然而,引入和传播感染的风险仍然存在，因为当不遵守个人卫生时，病毒很容易传播。
方法：为了确定HAV亚型在拉脱维亚境内的传播，对259例血清样品进行了HAV的VP1/P2A基因组区扩增和测序。本研究进行了分子生物学调查和分子流行病学调查。人口统计数据(性别，年龄),疾病数据(肝炎症状，住院治疗,疫苗接种)和流行病学数据(疫情的一部分，可能的感染源,最近的旅行)被收集。根据获得的序列，建立了系统发育树并分析了同源性，属于其他国家不同的HAV簇。
结果：从获得的数据中，结论是HAV亚型IA有13个簇和12个散发性病例，HAV亚型IB有8个簇和11个散发性病例，HAV亚型IIIA有1个簇和9个散发性病例。发现调查病例的感染来源不同,它们主要与与HAV患者的接触有关，旅行,以及注射毒品的人和男男性行为者之间，并且在不同年份观察到HAV相似序列的患病率。结论HAV亚型IA患者住院时间最长,平均9.3天,而IB亚型患者-7.3天，亚型IIIA-7.7天。分析疫苗接种的数据，结果发现，大多数人都没有接种疫苗或疫苗接种状态未知。
结论：所有这些都得出了结论，即应用分子生物学方法对HAV进行分析并对流行病学数据进行仔细分析可以帮助更好地了解感染的传播方式，调查当地疫情，检测输入性感染病例并跟踪病毒的再循环。
方法：为了确定HAV亚型在拉脱维亚境内的传播，对259例血清样品进行了HAV的VP1/P2A基因组区扩增和测序。本研究进行了分子生物学调查和分子流行病学调查。人口统计数据(性别，年龄),疾病数据(肝炎症状，住院治疗,疫苗接种)和流行病学数据(疫情的一部分，可能的感染源,最近的旅行)被收集。根据获得的序列，建立了系统发育树并分析了同源性，属于其他国家不同的HAV簇。
结果：从获得的数据中，结论是HAV亚型IA有13个簇和12个散发性病例，HAV亚型IB有8个簇和11个散发性病例，HAV亚型IIIA有1个簇和9个散发性病例。发现调查病例的感染来源不同,它们主要与与HAV患者的接触有关，旅行,以及注射毒品的人和男男性行为者之间，并且在不同年份观察到HAV相似序列的患病率。结论HAV亚型IA患者住院时间最长,平均9.3天,而IB亚型患者-7.3天，亚型IIIA-7.7天。分析疫苗接种的数据，结果发现，大多数人都没有接种疫苗或疫苗接种状态未知。
结论：所有这些都得出了结论，即应用分子生物学方法对HAV进行分析并对流行病学数据进行仔细分析可以帮助更好地了解感染的传播方式，调查当地疫情，检测输入性感染病例并跟踪病毒的再循环。
