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This review aims to gather and disseminate updated information regarding hepatitis A virus (HAV) in Latin America (LA) in the last 11 years, including seroprevalence, post-vaccination studies, virus detection in aqueous matrices and food samples, and outbreak reports. Only 24 seroprevalence studies were published between 2012 and 2023 with 55%-100% reported prevalences of anti-HAV IgG. Among the 25 LA countries, only eight of them have introduced HAV vaccines into their immunisation programs. Outbreaks of hepatitis A occurred between 2017-2019, mainly affecting men who have sex with men in Argentina, Brazil and Chile, probably as a consequence of the abrupt decline of young adults' immunity. This could be due to that young adult have never been infected in childhood (due to socio-health improvements) and are above the cut-off ages to be included when the vaccination programs were introduced. Although scarce, studies focused on environmental and food HAV surveillance have shown viral presence in these samples. Surface waters presented HAV detections between 1.2% and 86.7%, and untreated wastewaters between 2.8% and 70.9%. Genotypes found in all cases were IA and IC. The only wastewater-based epidemiology study showed to be a useful tool as a complement of traditional epidemiological surveillance. Only four LA countries have looked for HAV in food samples, with genome detection rates between 9% and 33%. Latin American HAV circulation scenario is changing. In countries where socioeconomic and sanitary conditions have not improved, the virus persists with high endemicity and the access to the vaccine should be re-evaluated by local governments. In countries where access to clean water, better sanitary conditions and HAV immunisation programs have been implemented, the number of cases among young adults seems to be increasing, alerting health authorities.

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BACKGROUND: Until 2005, when a single dose of vaccine was implemented in one-year-old children, the Hepatitis A virus (HAV) was responsible for approximately 90% of acute hepatitis cases in the paediatric population in Argentina. However, despite vaccination success, sporadic outbreaks of HAV still occur among adults. This study aimed to assess the seroepidemiology of HAV in Argentina, analysing IgG and IgM antibodies against HAV in a large population, both vaccinated and unvaccinated. METHODS: The study included 16,982 patients attending a hospital from 2001 to 2023. The cohort was divided into two groups: 16,638 individuals who were not reached by the vaccination program implemented in 2005 and 344 children who were covered by the universal vaccination. RESULTS: Anti-HAV IgG was detected in 56.7% of cases. The rate was significantly higher in individuals born after 2005 (77.7%) compared to those born before (56.3%), p < 0.001. The age groups 19-40 and 41-60 years showed the anti-HAV IgG lowest rates. On the other hand, 100/3956 cases (2.5%) with suspected acute hepatitis were positive for Anti-HAVIgM. Notably, none of these were born after the mandatory vaccine rollout. CONCLUSIONS: The study of this large cohort contributes to the understanding of the seroepidemiology of HAV. Although the implementation of the vaccine achieved its main goal, the age segment between 19 and 60 years does not reach the estimated threshold to achieve herd immunity. These findings reveal the importance of targeting vaccination campaigns, provide essential insights for public health planning, and guide future immunisation strategies against HAV in Argentina.

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Studies reporting the expression of hepatitis A virus (HAV) structural proteins, specifically recombinant VP1-2A containing an immunogenic activity, use the Escherichia coli system. Recombinant HAV proteins may represent a source of less expensive antigens for application in different diagnostic platforms. However, the formation of insoluble aggregates is an obstacle to obtaining large amounts of HAV proteins in their native form. To overcome this obstacle, some approaches were applied in this study to improve purification, solubility, and protein expression levels. Critical properties were evaluated. The introduction of another insertion codon to increase the protein concentration and vector activity was observed and verified by SDS-PAGE. The expression was established with 0.4 mM IPTG for 4 h at 37 °C. The VP1 protein was partially soluble at an isoeletric point (pI) of 6.45. The majority of HAV VP1-2A proteins measured 45.19 kDa in size and had a homogeneity of 53.58%. Multi-antigen print immunoassay (MAPIA) showed antigenicity at different HAV VP1-2A concentrations, and microsphere-based immunoassays showed a specificity of 100% and a sensitivity of 84%. HAV VP1-2A was characterized using different sensitivity methods to prove its biological activity, indicating its use as a tool for the diagnosis of Hepatitis A virus infection.

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Hepatitis A virus (HAV) is a common human pathogen found exclusively in primates. In a molecular and serologic study of 64 alpacas in Bolivia, we detected RNA of distinct HAV in ≈9% of animals and HAV antibodies in ≈64%. Complete-genome analysis suggests a long association of HAV with alpacas.

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OBJECTIVES: Hepatitis A (HAV) virus causes asymptomatic to life-treating fulminant hepatitis. During infection, patients show large viral excretion in their stools. Resistance of HAV to environmental conditions, allows us to recover viral nucleotide sequences from wastewater and trace its evolutionary history. METHODS: We characterize twelve years of HAV circulation in wastewater from Santiago, Chile, and conducted phylogenetic analyses to decipher the dynamics of circulating lineages. RESULTS: We observed the exclusive circulation of the HAV IA genotype. The molecular epidemiologic analyses showed a steady circulation of a dominant lineage with low genetic diversity (d = 0,007) between 2010 and 2017. An outbreak of Hepatitis A associated with men who have sex with men, in 2017 was associated with the irruption of a new lineage. Remarkably, a dramatic change in the dynamic of HAV circulation was observed in the period post-outbreak; between 2017 and 2021 when 4 different lineages were transiently detected. Exhaustive phylogenetic analyses indicate that these lineages were introduced and possibly derived from isolates from other Latin American countries. CONCLUSION: The HAV circulation in recent years in Chile is rapidly changing and suggests that this phenomenon could be a consequence of massive population migrations in Latin America caused by political instability and natural disasters.

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BACKGROUND: Hepatitis A virus (HAV) and hepatitis E virus (HEV) have enteric modes of transmission and are common causes of acute hepatitis in low- and middle-income countries. HEV is also characterised as a zoonotic infection and is prevalent in high-income countries. Data on HAV and HEV prevalence in Suriname, a middle-income country in South America, are scarce. METHODS: Serum samples of 944 and 949 randomly selected patients attending the Emergency Department at the Academic Hospital of Paramaribo, the capital of Suriname, were analysed for anti-HAV antibodies (anti-HAV) and anti-HEV antibodies (anti-HEV), respectively. Determinants of anti-HAV and anti-HEV positive serology were evaluated using multivariable logistic regression. RESULTS: Anti-HAV prevalence was 58.3% (95% CI 55.4 to 61.4%) and higher prevalence was independently associated with belonging to the Tribal or Indigenous population and older age. Anti-HEV prevalence was 3.7% (95% CI 2.6 to 5.0%) and higher prevalence was associated with Tribal and Creole ethnicity and older age. CONCLUSIONS: In Suriname, exposure to HAV is consistent with a very low endemic country and exposure to HEV was rare. Both viruses were more prevalent in specific ethnic groups. As anti-HAVantibodies were less frequently found in younger individuals, they could be susceptible to potential HAV outbreaks and might require HAV vaccination.

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BACKGROUND: Hepatitis A is responsible for 126,000,000 cases of acute viral hepatitis distributed heterogeneously worldwide, with a high disability-adjusted life year (DALY) rate, especially in low-income countries. Data related to Hepatitis A provides information to improve control measures and identify the population at risk. This study aims to analyze temporal trends of Hepatitis A in Brazil and its regions from 2007 to 2018, based on official notification data. METHODS: Data related to Hepatitis A reported cases from 2007 to 2018 were fitted to a joinpoint model by Brazilian regions, age groups, and gender, allowing the calculation of average annual percentage change (AAPC) and annual percentage change (APC) to estimate trends of Hepatitis A in Brazil. FINDINGS: From 2007 to 2018, 65,284 Hepatitis A cases notified in Brazil were available for analysis. The Northeast Region reported 18,732 (28.69%) cases, followed by the North Region reporting 18,430 (28.23%), the Southeast Region reporting 14,073 (21.55%), the South Region reporting 7909 (12.11%), and the Central-West Region reporting 6140 (9.4%), respectively. Temporal trend analysis showed that Hepatitis A incidence decreased from 2007 to 2016 in all Brazilian regions for individuals less than 20 years old, but increased in the South and Southeast males between 10 and 39 years after 2016. CONCLUSIONS: Hepatitis A endemicity is heterogeneous among Brazilian regions. In addition, an unexpected outbreak of HAV among Southeast and South adult males in 2016 resembles the outbreak in Europe, revealing a vulnerable population that should be prioritized by vaccination programs and control measures.

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Viral bivalve contamination is a recognized food safety hazard. Therefore, this study investigated the detection rates, seasonality, quantification, and genetic diversity of enteric viruses in bivalve samples (mussels and oysters). We collected 97 shellfish samples between March 2018 and February 2020. The screening of samples by qPCR or RT-qPCR revealed the detection of norovirus (42.3%), rotavirus A (RVA; 16.5%), human adenovirus (HAdV; 24.7%), and human bocavirus (HBoV; 13.4%). There was no detection of hepatitis A virus. In total, 58.8% of shellfish samples tested positive for one or more viruses, with 42.1% of positive samples contaminated with two or more viruses. Norovirus showed the highest median viral load (3.3 × 106 GC/g), followed by HAdV (median of 3.5 × 104 GC/g), RVA (median of 1.5 × 103 GC/g), and HBoV (median of 1.3 × 103 GC/g). Phylogenetic analysis revealed that norovirus strains belonged to genotype GII.12[P16], RVA to genotype I2, HAdV to types -C2, -C5, and -F40, and HBoV to genotypes -1 and -2. Our results demonstrate the viral contamination of bivalves, emphasizing the need for virological monitoring programs to ensure the quality and safety of shellfish for human consumption and as a valuable surveillance tool to monitor emerging viruses and novel variants.

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This study aims to evaluate the epidemiological and molecular features associated with HAV transmission in adults in Rio de Janeiro during a period of increased registered cases of HAV (2017-2018). Socio-epidemiological data and serum samples from anti-HAV IgM+ individuals were obtained. HAV RNA was RT-PCR amplified and sequenced for further phylogenetic and phylogeographic analyses. From fifty-two HAV IgM+ individuals, most were men (78.85%; p = 0.024), aged 20-30 years old (84.61%; p < 0.001), resided in the Rio de Janeiro north zone (31/52; 59.62%; p = 0.001), and are men who have sex with men (MSM) (57.69%; p = 0.002). Sexual practices were more frequent (96%) than others risk factors (food-borne (44%), water-borne (42.31%), and parenteral (34.62%)). Individuals who traveled to endemic regions had a 7.19-fold (1.93-36.04; p < 0.01) increased risk of HAV. Phylogenetic analysis revealed four distinct clades of subgenotype IA, three of them comprised sequences from European/Asian MSM outbreaks and one from Brazilian endemic strains. Bayesian Inference showed that the imported strains were introduced to Brazil during large mass sportive events. Sexual orientation and sexual practices may play a role in acquiring HAV infection. Public policies targeting key populations must be implemented to prevent further dissemination of HAV and other STIs.

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Infants' universal hepatitis A virus (HAV) single-dose vaccination has been highly effective for controlling HAV infection in Argentina, and in other Latin-American countries that adopted that strategy. Although antibodies wane over time, this has not been associated with HAV outbreaks or breakthrough infections, suggesting a relevant role for memory immunity. This study assessed long term humoral and cellular immune memory response after an average of 12 years follow-up of HAV single-dose vaccination. We selected 81 HAV-single dose vaccinated individuals from a 2015 study, including 54 with unprotective (UAL) and 27 with protective antibody levels (PAL) against HAV. Humoral memory response was assessed by measuring anti-HAV antibody titers at admission in both groups, and 30 days after a booster dose in the UAL group. Flow cytometry analysis of peripheral blood mononuclear cell samples stimulated with HAV antigen was performed in 47/81 individuals (21 with PAL, 26 with UAL) to identify activated CD4 + memory T cells or CD8 + memory T cells. The results showed that 48/52 (92%) individuals from UAL group who completed follow up reached protective levels after booster dose. In the PAL group, anti-HAV Abs waned in 2/27 (7%) individuals lacking seroprotection, while in 25/27 (93%) Abs remained >10 mUI/mL. HAV-specific memory CD4 + T cells were detected in 25/47 (53.2%) subjects while HAV-specific memory CD8 + T cells were observed in 16/47 (34.04%) individuals. HAV-specific memory CD4+ and CD8+ T cell responses were detected in 11/21 (52.4%) and in 9/21 (42.9%) subjects with PAL and in 14/26 (53.8%) and in 7/26 (26.9%) individuals with UAL, showing that the presence of memory T-cells was independent of the level or presence of anti-HAV antibodies. Long-term immunity demonstrated in the present work, including or not antibody persistence, suggests that individuals with waned Ab titers may still be protected and supports the single-dose HAV strategy.

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Introducción: La hepatitis es una enfermedad inflamatoria que afecta al hígado. El virus de la hepatitis A produce un cuadro infeccioso agudo por lo general autolimitado en el ser humano, para el cual no existe tratamiento específico. Objetivo: Realizar una actualización acerca del comportamiento y manejo actual de la infección por el virus de la hepatitis A. Métodos: Se realizó una revisión bibliográfica durante septiembre y octubre de 2021, se consultaron 156 artículos en idioma inglés y español de bases de datos como SciELO, PubMed, LILACS y Medigraphic, de ellos se utilizaron 30 citas. Se empleó la combinación de términos y operadores booleanos y métodos teóricos como: análisis-síntesis, inducción-deducción e histórico-lógico. Resultados: Se abordó el comportamiento de la infección causada por el virus de la hepatitis A, se hizo hincapié en su epidemiología, características morfológicas y funcionales que permiten su infectividad, evolución y manifestaciones clínicas, complicaciones, tratamiento y perspectivas actuales. Conclusiones: El virus de la hepatitis A produce un cuadro infeccioso agudo. Se presenta tanto de forma esporádica como epidémica. Es la forma más común de hepatitis viral aguda. La transmisión es de persona a persona por vía fecal oral. Los síntomas relacionados con las hepatitis virales agudas son variables e inespecíficos. El diagnóstico de certeza se realiza mediante las pruebas serológicas y técnicas de biología molecular para la identificación del virus. No existe tratamiento específico para esta infección.

Introduction: Hepatitis is an inflammatory disease that affects the liver. The hepatitis A virus produces a generally self-limited acute infectious picture in humans, for which there is no specific treatment. Objective: To update on current behavior and management of hepatitis A virus infection. Methods: A bibliographic review was carried out during September and October 2021, consulting 156 articles in English and Spanish from databases such as SciELO, PubMed, Lilacs and Medigraphic, of which 30 citations were used. The combination of Boolean terms and operators and theoretical methods such as: analysis-synthesis, induction-deduction and historical-logical was used. Results: The behavior of the infection caused by the hepatitis A virus was addressed, emphasizing its epidemiology, morphological and functional characteristics that allow its infectivity, evolution and clinical manifestations, complications, treatment and current perspectives. Conclusions: The hepatitis A virus produces an acute infectious picture. It occurs both sporadically and epidemically. It is the most common form of acute viral hepatitis. Transmission is person-to-person by the fecal oral route. Symptoms related to acute viral hepatitis are variable and nonspecific. The diagnosis of certainty is carried out by means of serological tests and molecular biology techniques for the identification of the virus. There is no specific treatment for this infection.

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Hepatitis A virus (HAV) is the major cause of enterically transmitted infectious hepatitis. Between 2016 and 2017, the number of confirmed cases of hepatitis A virus (HAV) increased from 64 to 786 in São Paulo affecting mainly adults aged between 18 and 39 years (80%) and males (88%). To support epidemiological surveillance, the present study monitored the presence of HAV in urban sewage samples collected bimonthly for 1 year (November 2017-November 2018) in the central region of the city, where most of cases were detected. Sewage samples were concentrated by polyethylene glycol precipitation and HAV RNA was quantified by RT-qPCR. Nucleotide sequencing targeting the VP1/2A junction region was carried out to genotype the HAV strains. HAV was detected in 76.9% (40/52) of the samples, with a geometric mean viral load of 5.09 × 104 (± SD 4.51 × 105) genome copies (GC/L) (Mauá Street) and 5.27 × 104 (± SD 1.26 × 106) GC/L (Prestes Maia Avenue). Of the 40 positive samples, 8 were typed as HAV subgenotype IA [100% nucleotide (nt) identity with HAV strain VRD_521_2016]. Highest homology was obtained with sequences from European countries (Italy, Spain) and Israel, all of which had reported recent HAV outbreaks associated with men who have sex with men. Our results highlight that wastewater surveillance is a useful tool to support investigating HAV outbreaks in the community, including circulating genotypes.

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Viral hepatitis, secondary to infection with hepatitis A, B, C, D, and E viruses, are a major public health problem and an important cause of morbidity and mortality. Despite the huge medical advances achieved in recent years, there are still points of conflict concerning the pathogenesis, immune response, development of new and more effective vaccines, therapies, and treatment. This review focuses on the most important research topics that deal with issues that are currently being solved, those that remain to be solved, and future research directions. For hepatitis A virus we will address epidemiology, molecular surveillance, new susceptible populations as well as environmental and food detections. In the case of hepatitis B virus, we will discuss host factors related to disease, diagnosis, therapy, and vaccine improvement. On hepatitis C virus, we will focus on pathogenesis, immune response, direct action antivirals treatment in the context of solid organ transplantation, issues related to hepatocellular carcinoma development, direct action antivirals resistance due to selection of resistance-associated variants, and vaccination. Regarding hepatitis D virus, we describe diagnostic methodology, pathogenesis, and therapy. Finally, for hepatitis E virus, we will address epidemiology (including new emerging species), diagnosis, clinical aspects, treatment, the development of a vaccine, and environmental surveillance.

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This review aims to summarize the current evidence on the treatment of viral hepatitis, focusing on its clinical management. Also, future treatment options and areas of potential research interest are detailed. PubMed and Scopus databases were searched for primary studies published within the last ten years. Keywords included hepatitis A virus, hepatitis B virus (HBV), hepatitis C virus, hepatitis D virus (HDV), hepatitis E virus, and treatment. Outcomes reported in the studies were summarized, tabulated, and synthesized. Significant advances in viral hepatitis treatment were accomplished, such as the advent of curative therapies for hepatitis C and the development and improvement of hepatitis A, hepatitis B, and hepatitis E vaccination. Drugs that cure hepatitis B, going beyond viral suppression, are so far unavailable; however, targeted antiviral drugs against HBV (immunomodulatory therapies and gene silencing technologies) are promising approaches to eradicating the virus. Ultimately, high vaccination coverage and large-scale test-and-treat programmes with high screening rates may eliminate viral hepatitis and mitigate their burden on health systems. The development of curative hepatitis C treatment renewed the enthusiasm for curing hepatitis B, albeit further investigation is required. Novel therapeutic options targeting HDV life cycle are currently under clinical investigation.

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Hepatitis A (HA) is an acute human infectious disease caused by a positive single-stranded RNA virus (HAV). It is mainly acquired through the fecal-oral route and is primarily spread by contact between people and exposure to contaminated water and food. Recently, large outbreaks of HA have been reported by low and moderate endemicity countries, emphasizing its importance in public health and the need for rapid and large-scale diagnostic tests to support public health decisions on HA. This work proposes a new tool for HAV diagnosis based on the association of surface plasmonic resonance with major capsid protein VP1 (SPR-HAVP1 assay), detecting IgM antibodies for HAV in human serum samples. Structural analyses of VP1 B-lymphocyte epitopes showed continuous and discontinuous epitopes. The discontinuous epitopes were identified in the N-terminal region of the VP1 protein. Both epitope types in the VP1 protein were shown by the reactivity of VP1 in native and denaturing conditions to IgM anti-HAV, which was favorable to tests of VP1 in the SPR assays. SPR-HAVP1 assays showed good performance in the detection of IgM polyclonal antibody anti-HAV. These assays were performed using a COOH5 sensor chip functionalized with VP1 protein. The sensorgram record showed a significant difference between positive and negative serum samples, which was confirmed by analysis of variation of initial and final dissociation values through time (ΔRUd/t). The data gathered here are unequivocal evidence that the SPR-HAVP1 strategy can be applied to detect IgM antibodies in human serum positive to the HAV. This is a new tool to be explored to diagnose human HAV infections.

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Foodborne viruses including hepatitis A virus (HAV), norovirus (NoV), rotavirus (RoV) and hepatitis E virus (HEV) are easily transmitted through contaminated seafoods. The current research was done to assess the incidence of RoV, NoV GI and GII,hAV and hEV in fish and shrimp samples caught from the Persian Gulf, Iran. Three-hundred and twenty fish and shrimp samples were collected. The presence of foodborne viruses were assessed by the real-time PCR. Forty-nine out of 320 (15.31%) fish and shrimp samples were positive for foodborne viruses. Distribution of hAV, NoV GI and NoV GII amongst all studied samples were 0.93%, 5.93% and 8.43%, respectively. hEV and RoV viruses were not found in studied samples. Parastromateus niger and Scomberomorus commerson fish and Penaeus monodon shrimp were the most frequently contaminated samples. Simultaneous incidence of hAV and NoV GI and hAV and NoV GII were 0.31% and 0.93%, respectively. Distribution of foodborne viruses in samples collected through spring, summer, autumn and winter seasons were 14.28%, 9.33%, 11.76% and 24.44%, respectively. Findings revealed that the incidence of foodborne viruses was significantly associated with seafood species and also season of sampling.(AU)

Vírus transmitidos por alimentos, incluindo hepatite A (HAV), norovírus (NoV), rotavírus (RoV) e hepatite E (HEV) são facilmente transmitidos através de frutos do mar contaminados. Esta pesquisa foi realizada para avaliar a incidência de RoV, NoV GI e GII, hAV e hEV em amostras de peixes e camarões capturadas no Golfo Pérsico, Irã. Foram coletadas 300 amostras de peixes e camarões. A presença de vírus transmitidos por alimentos foi avaliada por PCR em tempo real. Quarenta e nove das 320 amostras de peixes e camarões (15,31%) foram positivas para vírus transmitidos por alimentos. A distribuição de hAV, NoV GI e NoV GII entre as amostras estudadas foi 0,93%, 5,93% e 8,43%, respectivamente. Os vírus hEV e RoV não foram encontrados nas amostras estudadas. Os peixes Parastromateus niger e Scomberomorus commerson e o camarão Penaeus monodon foram as amostras mais frequentemente contaminadas. A incidência simultânea de hAV e NoV GI, e hAV e NoV GII foi de 0,31% e 0,93%, respectivamente. A distribuição dos vírus transmitidos por alimentos nas amostras coletadas na primavera, verão, outono e inverno foi de 14,28%, 9,33%, 11,76% e 24,44%, respectivamente. Os resultados demonstram que a incidência de vírus transmitidos por alimentos foi significativamente associada às espécies de frutos do mar e também à época da amostragem.(AU)

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Outbreaks of hepatitis A may occur in countries of medium and high socioeconomic levels in which the population generally exhibits an increased susceptibility in young adults to this infection if they are not vaccinated against the hepatitis A virus (HAV). In Europe, an outbreak involved approximately 22 European countries with 4475 cases reported from 2016 to 2018; most of them were men who have sex with men (MSM). This outbreak expanded to North and South America, including Brazil, particularly in São Paulo city with 1547 reported cases from 2016 to 2019. In the present study, we characterized the HAV strains involved in the acute hepatitis A cases identified in the reference centers of São Paulo city during this outbreak. A total of 51 cases with positive anti-HAV IgM were included, 80.4% male, 68.6% of them between 20 and 40 years old and 41.7% MSM. HAV RNA was detected in 92% (47/51) of the cases. Subgenotype IA of HAV was identified and most of the strains were closely related to that isolated in outbreaks that occurred in different European countries in 2016. These results showed the epidemiological relation between these outbreaks and reinforce the need to implement vaccination against hepatitis A for the adult population, particularly for a population with a high-risk behavior.

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There are rare instances where patients with acute hepatitis A virus infection subsequently developed autoimmune hepatitis. The diagnosis of autoimmune hepatitis in this setting is challenging. Furthermore, information on treatment with steroids or other immune suppressants, duration of therapy and possibility of treatment discontinuation is currently unclear. Here we report a case series of four patients with histology proven autoimmune hepatitis after hepatitis A virus infection. We describe the presenting features, diagnosis, treatment and long-term outcomes of these cases. This case series provides a insight into the clinical presentation and treatment of autoimmune hepatitis after hepatitis A infection with interesting take home points for clinical hepatologists.

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Hepatitis A virus (HAV) is a common infection that is transmitted through the fecal-oral route, shed in the stool of infected individuals, and spread either by direct contact or by ingesting contaminated food or water. Each year, approximately 1.4 million acute cases are reported globally with a major risk factor for exposure being low household socioeconomic status. Recent trends show a decrease in anti-HAV antibodies in the general population, with concomitant increases in the numbers of HAV outbreaks. In line with a recreational water study, this effort aims to assess the prevalence of salivary IgG antibodies against HAV and subsequent incident infections (or immunoconversions) in visitors to a tropical beach impacted by a publicly owned treatment works (POTW). We applied a multiplex immunoassay to serially collected saliva samples gathered from study participants who recreated at Boquerón Beach, Puerto Rico. Analysis of assay results revealed an immunoprevalence rate of 16.17% for HAV with 1.43% of the cohort immunoconverting to HAV. Among those who immunoconverted, 10% reported chronic gastrointestinal symptoms and none experienced diarrhea. Tests on water samples indicated good water quality with low levels of fecal indicator bacteria; however, the collection and analysis of saliva samples afforded the ability to detect HAV infections in beachgoers. This rapid assay serves as a cost-effective tool for examining exposure to environmental pathogens and can provide critical information to policy makers, water quality experts, and risk assessment professionals seeking to improve and protect recreational water and public health.

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INTRODUCTION: Several Picornaviruses are pathogens that generate serious problems for human and animal health worldwide. Vaccination is an attractive approach to fight against picornaviruses. In this regard, the development of low-cost vaccines is a priority to ensure coverage; especially in developing and low-income countries. In this context, plant-made vaccines are a convenient technology since plant cells are low-cost bioreactors capable of producing complex antigens that preserve their antigenic determinants; moreover, they can serve as biocapsules to achieve oral delivery. AREAS COVERED: In the present review the advances in the development of plant-made vaccines against picornaviruses are summarized and placed in perspective. The main diseases that have been targeted using this approach include Poliovirus, Food and mouth disease virus, Hepatitis A virus, and Enterovirus 71. EXPERT OPINION: Several vaccine candidates against picornavirus have been characterized at the preclinical level; with many of them capable of inducing humoral and cellular responses that led to neutralization of pathogens when evaluated in vitro and test animal challenge assays. Plant-made vaccines are a promise to fight picornaviruses; especially in the developing world where limited resources hamper vaccination coverage. A critical analysis of the road ahead for this technology is provided.

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