Challenges in Management of Hepatitis A Virus Epidemiological Transition in Mexico

Current perspectives of viral hepatitis

Viral hepatitis represents a major danger to public health, and is a globally leading cause of death. The five liver-specific viruses: Hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus, and hepatitis E virus, each have their own unique epidemiology, structural biology, transmission, endemic patterns, risk of liver complications, and response to antiviral therapies. There remain few options for treatment, in spite of the increasing prevalence of viral-hepatitis-caused liver disease. Furthermore, chronic viral hepatitis is a leading worldwide cause of both liver-related morbidity and mortality, even though effective treatments are available that could reduce or prevent most patients' complications. In 2016, the World Health Organization released its plan to eliminate viral hepatitis as a public health threat by the year 2030, along with a discussion of current gaps and prospects for both regional and global eradication of viral hepatitis. Today, treatment is sufficiently able to prevent the disease from reaching advanced phases. However, future therapies must be extremely safe, and should ideally limit the period of treatment necessary. A better understanding of pathogenesis will prove beneficial in the development of potential treatment strategies targeting infections by viral hepatitis. This review aims to summarize the current state of knowledge on each type of viral hepatitis, together with major innovations.

Tracing the History of Hepatitis E Virus Infection in Mexico: From the Enigmatic Genotype 2 to the Current Disease Situation

Hepatitis E virus (HEV) is the major cause of acute viral hepatitis worldwide. This virus is responsible for waterborne outbreaks in low-income countries and zoonosis transmission in industrialized regions. Initially, considered self-limiting, HEV may also lead to chronic disease, and evidence supports that infection can be considered a systemic disease. In the late 1980s, Mexico became a hot spot in the study of HEV due to one of the first virus outbreaks in Latin America related to enterically transmitted viral non-A, non-B hepatitis. Viral stool particles recovered from Mexican viral hepatitis outbreaks represented the first identification of HEV genotype (Gt) 2 (Gt2) in the world. No new findings of HEV-Gt2 have been reported in the country, whereas this genotype has been found in countries on the African continent. Recent investigations in Mexico have identified other strains (HEV-Gt1 and -Gt3) and a high frequency of anti-HEV antibodies in animal and human populations. Herein, the potential reasons for the disappearance of HEV-Gt2 in Mexico and the advances in the study of HEV in the country are discussed along with challenges in studying this neglected pathogen. These pieces of information are expected to contribute to disease control in the entire Latin American region.

Potential of CRISPR/Cas system as emerging tools in the detection of viral hepatitis infection

Viral hepatitis, the most common cause of inflammatory liver disease, affects hundreds of millions of people worldwide. It is most commonly associated with one of the five nominal hepatitis viruses (hepatitis A-E viruses). HBV and HCV can cause acute infections and lifelong, persistent chronic infections, while HAV and HEV cause self-limiting acute infections. HAV and HEV are predominantly transmitted through the fecal-oral route, while diseases transmitted by the other forms are blood-borne diseases. Despite the success in the treatment of viral hepatitis and the development of HAV and HBV vaccines, there is still no accurate diagnosis at the genetic level for these diseases. Timely diagnosis of viral hepatitis is a prerequisite for efficient therapeutic intervention. Due to the specificity and sensitivity of clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated sequences (Cas) technology, it has the potential to meet critical needs in the field of diagnosis of viral diseases and can be used in versatile point-of-care (POC) diagnostic applications to detect viruses with both DNA and RNA genomes. In this review, we discuss recent advances in CRISPR-Cas diagnostics tools and assess their potential and prospects in rapid and effective strategies for the diagnosis and control of viral hepatitis infection.

Modeling the Transmission Dynamics of Hepatitis A with Combined Vaccination and Sanitation Mitigation

A mathematical model for the Hepatitis A Virus (HAV) epidemiology with dual transmission mechanisms is developed and presented. The model considers vaccination and sanitation as mitigation strategies. The effective reproductive number was derived and employed to study the stability of the model. Using Routh's stability criteria, the local stability of a disease-free equilibrium was determined, whereas the global stability of the endemic equilibrium was attained through a suitable Lyapunov function. Furthermore, bifurcation analysis is carried out using the centre manifold theory to ascertain its nature and implication for disease control. It was revealed that the model exhibits a forward bifurcation indicating the possibility of disease eradication when the effective reproduction number is kept below unity. Numerical results indicate that infection rates decrease quantitatively when at least one control measure is effectively implemented. It was deduced that combining vaccination and sanitation yields even fewer cases, making it the best alternative for eliminating Hepatitis A (HA) infection from the community. A sensitivity analysis was conducted to ascertain the parameters of the strong influence that could significantly affect the system. It was revealed that constant recruitment and vaccination coverage were the most critical parameters affecting the system. In addition, the study found that direct transmission plays an essential role in the occurrence of HA infection. In contrast, indirect transmission contributes marginally but significantly to the prevalence of HA infection.

A 2019 Outbreak Investigation of Hepatitis A Virus Infections in the United States Linked to Imported Fresh Blackberries

Globally, hepatitis A virus (HAV) is one of the most common agents of acute viral hepatitis and causes approximately 1.4 million cases and 90,000 deaths annually despite the existence of an effective vaccine. In 2019, federal, state, and local partners investigated a multi-state outbreak of HAV infections linked to fresh blackberries sourced from multiple suppliers in Michoacán, Mexico. A total of 20 individuals with outbreak-related HAV infection were reported in seven states, including 11 hospitalizations, and no deaths. The Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and Nebraska State and Douglas County Health Departments conducted a traceback investigation for fresh blackberries reportedly purchased by 16 ill persons. These individuals reported purchasing fresh blackberries from 11 points of service from September 16 through 29, 2019 and their clinical isolates assessed through next-generation sequencing and phylogenetic analysis were genetically similar. The traceback investigation did not reveal convergence on a common grower or packing house within Mexico, but all of the blackberries were harvested from growers in Michoacán, Mexico. FDA did not detect the pathogen after analyzing fresh blackberry samples from four distributors, one consumer, and from nine importers at the port of entry as a result of increased screening. Challenges included gaps in traceability practices and the inability to recover the pathogen from sample testing, which prohibited investigators from determining the source of the implicated blackberries. This multi-state outbreak illustrated the importance of food safety practices for fresh produce that may contribute to foodborne illness outbreaks.

Acute Hepatitis A Virus Infection in Tobruk, Eastern Libya: Increasing Trends After 2017

Acute hepatitis A is a self-limited liver inflammation caused by hepatitis A virus (HAV) infection. The infection is transmitted by direct contact from person to person via fecal-oral routes, or through consuming contaminated food and water. This study aims to estimate the frequency of HAV infection from medical records of Tobruk Medical Center, eastern Libya and its distribution during 6 years. The medical records department of Tobruk Medical Center follows guidelines of the international classification of diseases-10 for coding the diseases. The research estimates the frequency and distribution of HAV infection based on age and sex during the period from January 2015 to December 2020. HAV screening assay was performed using commercially available enzyme-linked immunosorbent assays HAV IgM microwell. 245 cases were recorded, 53.5% of cases were males. HAV infection was the most prevalent (92.6%) in age groups of < 5-20 years. A significant rise in the occurrence of HAV infection in the last three years was reported (p < 0.05). More than half of the cases (68%) were reported in 2019 and 2020. No case fatality rate was reported in the present study. There is an increase in the frequency of HAV infection in the last 3 years and the younger age groups (under 20 years old) are more vulnerable to HAV infection. More prevention and control efforts towards this age group should be a top public health priority to avoid the possibility of HAV outbreaks in the future.

A hospital-based study of the prevalence of HBV, HCV, HIV, and liver disease among a low-income population in West Mexico

INTRODUCTION AND OBJECTIVES

Viral hepatitis is a global health problem with unequal distribution of disease burden in which low-income people are at higher risk for acquisition and underlying liver diseases. This study aimed to seek the prevalence of hepatitis B and C viruses, HIV, and liver damage among low-income patients attending a public tertiary care hospital in West Mexico.

METHODS

A retrospective/cross-sectional study at the Department of Genomic Medicine in Hepatology was conducted between March 1, 2016 to March 30, 2017. A total of 10,352 patients tested for anti-HCV, HBsAg, or anti-HIV (n=23,074) were included. Age, gender, and hospital service were registered. Liver fibrosis was assessed using APRI and FIB-4 scores.

RESULTS

Overall, 3.9% were anti-HCV+ (305/7848), 1.0% were HBsAg+ (80/7894), and 2.9% were anti-HIV+ (210/7332). A 43.8% (750/1959) of patients negative for all viruses had either abnormal AST, ALT, or GGT (≥40 UI/L). Also, significant liver fibrosis (APRI ≥ 0.7) was prevalent in 10.6% (191/1804). In patients who tested positive for viral infections, liver fibrosis was detected in 20.4% (11/54) of HBsAg+, 34.2% (53/155) in anti-HCV+ and 15.5% (16/103) in anti-HIV+. Anti-HCV+ was highest in Geriatrics (11.1%), HBsAg+ in HIV patients (3.0%) and anti-HIV+ in Emergency room attendees (33.3%).

CONCLUSION

High seroprevalence of HCV, HBV, and HIV infections was found among the studied population. Significant liver fibrosis was detected in negative and positive patients for viral infections. Medical services need to continuously test for viral infections, promote early detection of chronic liver damage and identify target patients for elimination strategies to decrease disease burden.

The global trends and regional differences in incidence and mortality of hepatitis A from 1990 to 2019 and implications for its prevention

Background and purpose

Despite decades of improved sanitation and hygiene measures and vaccine introduction, hepatitis A has been spread through numerous outbreaks globally. We used data from the Global Burden of Disease (GBD) study to quantify hepatitis A burden at the global, regional and national levels.

Methods

Annual incident cases, deaths, age-standardized incidence rates (ASIRs), and age-standardized mortality rates (ASMRs) of hepatitis A between 1990 and 2019 were derived from the GBD study 2019. Percentage changes of cases and deaths, and estimated annual percentage changes (EAPCs) of ASIRs and ASMRs were calculated to quantify their temporal trends.

Results

Global hepatitis A incident cases increased by 13.90% from 139.54 million in 1990 to 158.94 million in 2019. ASIR of hepatitis A remained stable (EAPC = 0.00, 95% CI −0.01 to 0.01), whereas ASMR decreased (EAPC = −4.63, 95% CI −4.94 to −4.32) between 1990 and 2019. ASIR increased in low (EAPC = 0.09, 95% CI 0.04 to 0.14) and low-middle (EAPC = 0.04, 95% CI 0.03 to 0.06) socio-demographic index (SDI) regions. For GBD regions, the most significant increases of ASIR were detected in high-income Asia Pacific (EAPC = 0.53, 95% CI 0.41 to 0.66), Oceania (EAPC = 0.31, 95% CI 0.25 to 0.36), and Australasia (EAPC = 0.28, 95% CI 0.13 to 0.44). EAPC of ASIR was positively associated with SDI value in countries and territories with SDI value ≥ 0.7 (ρ = −0.310, p < 0.001).

Conclusion

There is an unfavorable trend that hepatitis A is still pending in hyperendemic regions and is emerging in low endemic regions. These highlight the need of targeted and specific strategies to eliminate hepatitis A, such as sanitation measures and a comprehensive plan for surveillance and vaccination against hepatitis A.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12072-021-10232-4.

Spatial and Temporal Distribution of Hepatitis A Virus and Hepatitis E Virus Among Children with Acute Hepatitis in Mexico

Hepatitis A virus (HAV) and hepatitis E virus (HEV) cause most of the global burden of viral hepatitis. Geographical and seasonal patterns contribute to the epidemiological status of infectious diseases. The extent of these features in the setting of HAV and HEV infections has not been analyzed in detail. This point is important in highly endemic countries of both viruses, where the pediatric population is at high risk of contracting these infections. A comparison between the frequency of antibodies to HAV and HEV and viral RNA detection in serum samples from pediatric patients with acute hepatitis from South and West Mexico was performed. All samples were positive for HAV mono-infection, which was most frequently detected in the metropolitan areas during the rainy season in the South (90%) and all year round in the West (42%). No HEV mono-infection was detected in the studied regions. A 58% frequency for HAV/HEV co-infection was found in the West, predominantly in the metropolitan areas during the rainy months. A 10% frequency for co-infection broadly distributed in the South throughout the year was also found. Our findings underscore that the distribution of HAV and HEV infections varies through the year and differs among Mexico's distinct geographical regions.

Hepatitis A vaccination and its immunological and epidemiological long-term effects - a review of the evidence

Hepatitis A virus (HAV) infections continue to represent a significant disease burden causing approximately 200 million infections, 30 million symptomatic illnesses and 30,000 deaths each year. Effective and safe hepatitis A vaccines have been available since the early 1990s. Initially developed for individual prophylaxis, HAV vaccines are now increasingly used to control hepatitis A in endemic areas. The human enteral HAV is eradicable in principle, however, HAV eradication is currently not being pursued. Inactivated HAV vaccines are safe and, after two doses, elicit seroprotection in healthy children, adolescents, and young adults for an estimated 30-40 years, if not lifelong, with no need for a later second booster. The long-term effects of the single-dose live-attenuated HAV vaccines are less well documented but available data suggest they are safe and provide long-lasting immunity and protection. A universal mass vaccination strategy (UMV) based on two doses of inactivated vaccine is commonly implemented in endemic countries and eliminates clinical hepatitis A disease in toddlers within a few years. Consequently, older age groups also benefit due to the herd protection effects. Single-dose UMV programs have shown promising outcomes but need to be monitored for many more years in order to document an effective immune memory persistence. In non-endemic countries, prevention efforts need to focus on 'new' risk groups, such as men having sex with men, prisoners, the homeless, and families visiting friends and relatives in endemic countries. This narrative review presents the current evidence regarding the immunological and epidemiological long-term effects of the hepatitis A vaccination and finally discusses emerging issues and areas for research.

Hepatitis A: Epidemiology, Natural History, Unusual Clinical Manifestations, and Prevention

Hepatitis A virus (HAV) is a positive-strand RNA virus that is transmitted feco-orally through person-to-person contact. Outbreaks are often linked to poor sanitation, overcrowding, or food and water contamination. Infection is often asymptomatic in children, but adults present with jaundice, abdominal pain, hepatitis, and hyperbilirubinemia. Diagnosis is through detection of immunoglobulin M antibodies against HAV, and treatment is supportive. Vaccination is the mainstay of prevention and should be given before exposure whenever possible.