Risk factors associated with hepatitis D virus infection and preventive strategies in Mongolia

BACKGROUND

Hepatitis D virus (HDV) infection is highly prevalent in Mongolia. We aimed to identify the risk factors associated with HDV infection, propose preventive strategies, and evaluate the outcomes of a 3-year collaborative project between Taiwan and Mongolia.

METHODS

In 2016 and 2018, we conducted onsite visits to Mongolia. Mongolian investigators collected questionnaires focusing on risk factors, demographic characteristics, and serum samples for acute HDV infections. Furthermore, 19 Mongolian seed teachers participated in a 1-week workshop on infection control in Taiwan. Subsequently, these seed teachers trained more than 400 medical personnel in Mongolia. To assess secular changes in acute HDV infection, we reviewed the registration data from the National Center for Communicable Disease (NCCD) in Mongolia between 2011 and 2021.

RESULTS

Among the 194 Mongolian patients, 108 had dual infection with hepatitis B virus (HBV) and HDV, while 86 had acute hepatitis B (AHB). Patients with HBV/HDV dual infections were older (28.6 vs 25.5 years, p = 0.030) and had lower rates of positive hepatitis B e antigen in their sera, lower rates of serum HBV DNA exceeding 2000 IU/mL, and higher rates of having received dental treatment (59.4% vs 40.5%, p = 0.014) and injection therapy (64.2% vs 44.0%, p = 0.009) compared with those with AHB. Analysis of NCCD data revealed that new HDV infection cases were more prevalent between 2011 and 2015 (111.20 ± 29.79 cases/y) and decreased to 54.67 ± 27.34 cases/y between 2016 and 2021 ( p = 0.010).

CONCLUSION

Dental treatment and injections were associated with a higher risk of acute HDV infections in Mongolia. Through collaborative efforts, the incidence rate of HDV infection has declined in recent years.

Prevalence, characteristics, and virologic correlations of hepatitis delta (D) among patients with hepatitis B surface antigen in Mongolia

Clinical and biochemical features of hepatitis delta virus (HDV) infections in Mongolia remain largely unknown. We aimed to investigate the clinical characteristics of HDV patients in Mongolia using several markers. The 143 hepatitis B surface antigen (HBsAg)-positive patients were divided into 122 HDV-positive and 21 HDV-negative patients by HDV RNA positivity. Subgroup analysis was performed between hepatitis B e antigen (HBeAg)-positive and -negative HDV-positive patients. Liver function, quantitative HBsAg (qHBsAg), anti-HDV Immunoglobulin (Ig) M, Mac-2 binding protein glycosylation isomer (M2BPGi), hepatitis B virus (HBV) DNA level, and HDV RNA level were tested. HDV RNA was positive in 85.3% (122/143) of patients showing anti-HDV IgG. Liver disease activity was higher in HDV-positive patients than in HDV-negative patients. The HDV-positive group included a higher proportion of patients with high qHBsAg and M2BPGi levels (p < 0.001). The positivity rate for anti-HDV IgM was significantly higher in the HDV-positive group (p < 0.001). HDV RNA levels showed an inverse correlation with qHBsAg levels in HBeAg-positive-HDV-positive patients (r = -0.49, p = 0.034), and a positive correlation with qHBsAg levels in HBeAg-negative patients (r = 0.35, p < 0.001). Hepatitis B virus (HBV) DNA and HDV RNA levels did not show any correlation. M2BPGi levels likewise did not correlate with HDV RNA levels. A high positivity rate for HDV RNA was observed for HBV patients in Mongolia using the highly sensitive HDV RNA assay. The positivity rate for anti-HDV IgM was high in HDV RNA-positive patients. Severity of liver disease and M2BPGi levels were both high in the HDV RNA-positive group.