Yoneira Sulbaran

Coinfection between hepatitis viruses and human immunodeficiency virus (HIV) significantly increases liver disease and AIDS progression. This retrospective cross-sectional study evaluated the prevalence and genetic diversity of hepatitis B (HBV) and C viruses (HCV) among people living with HIV (PLWH) in Venezuela’s Capital District. A total of 420 serum samples collected between 2022 and 2025 were tested for serological and molecular markers, including whole-genome HBV sequencing via next-generation sequencing (NGS) to characterize viral genotype distribution and mutations. Seroprevalences for HBsAg, anti-HBc, and anti-HCV were 2.9%, 20%, and 4.0%, respectively. HBV exposure was significantly higher in older men, with no differences between treatment-naïve and treated patients. Occult HBV infection (OBI) prevalence decreased compared to 2014 data (seropositive: 7% vs. 16%, seronegative: 0.9% vs. 20%). This decline, along with the higher HBV exposure among older adults, may be partially attributed to the universal HBV vaccination introduced in Venezuela in 1998, as well as modifications in antiretroviral therapy affecting HBV replication. Notably, key vaccine- and diagnostic-escape mutations were detected in OBI cases, highlighting clinical and public health concerns. Increased HCV prevalence appears to be linked to rising intravenous drug use in the country. HBV phylogenetic analysis revealed genotype F3 as predominant, followed by F1b (Cosmopolitan clade), while HCV showed genotype 1a to be the most frequent, followed by 1b and 3a. These findings underscore the success of immunization efforts but highlight the urgent need for continuous molecular surveillance and updated public health policies, including targeted harm-reduction programs, to control viral hepatitis in vulnerable populations.

Hepatitis D virus (HDV) is a satellite virus that requires the presence of a helper virus, the hepatitis B virus (HBV). Soon after its discovery by Mario Rizzetto in 1977, severe outbreaks of fulminant hepatitis D occurred in the past century, in indigenous populations from the Western and Southern (Amazon) regions of Venezuela, while the indigenous population from the Eastern region (Orinoco Delta) has been found to be free of this virus. Data on the prevalence of HDV infection in Venezuela are still highly imprecise. The aim of this study is to provide insights into the current situation of this disease in the country. Evidence of exposure and infection with HDV was found again mainly in indigenous populations, although also one patient with hepatitis B from the capital was found to be infected with HDV genotype 1. The genotype found in the indigenous Bari population was HDV genotype 1, the same lineage (a putative new subgenotype 1j) previously identified in this region in both Venezuela and Colombia. Although scarce information is still available about the burden of HDV infection in Venezuela, the few studies available are consistent in showing an epidemic concentrated mainly in some, but not all, indigenous populations. Reflex testing is needed to have a better appraisal of this disease in the country.

Hepatitis E virus (HEV) is an emerging zoonotic pathogen of increasing concern in developed regions and represents a major cause of acute viral hepatitis worldwide, primarily transmitted via the fecal–oral route. Although most infections are self-limiting, immunocompromised individuals, such as people living with human immunodeficiency virus (PLWH) and pregnant women, are at risk of severe outcomes, including chronic infection and fatal liver failure, respectively. This study was aimed at evaluating the prevalence and genetic diversity of HEV in PLWH and relevant ecological niches (swine and wastewater) in Venezuela. A total of 417 serum samples from PLWH, 85 wastewater samples, and 67 swine fecal samples were tested for serological or molecular HEV markers. The seroprevalence of anti-HEV antibodies among PLWH was 0.2% for IgM and 5.5% for IgG. HEV RNA was not detected in samples from PLWH or wastewater; however, a 1.5% prevalence of active infection was identified in swine. Phylogenetic analysis of a complete HEV genome revealed an unassignable subtype within genotype 3, tentatively designated as 3p. To the best of our knowledge, this study provides the first molecular characterization and report on HEV frequency in PLWH, wastewater, and swine in Venezuela.

Background: Madariaga virus (MADV), formerly known as the South American variant of Eastern Equine Encephalitis virus (EEEV), is an alphavirus that belongs to the Togaviridae family and has been periodically infecting equids in Venezuela since its first identification in 1975. This study reports the isolation and molecular characterization of MADV isolated from a horse in December 2024 in the context of MADV cases reported in Venezuela. Methods: Antibodies to the rabies virus were detected by indirect immunofluorescence, and to the Equine Infectious Anemia virus (EIAV) by passive immunodiffusion. MADV RNA was detected by qRT-PCR. The sequence of the complete viral genome was obtained by next-generation sequencing. Results: The sequence of this virus was highly similar to that of the only human case of MADV reported in the country in 2016, as well as to a sequence of a virus isolated from a horse in Colombia in 2002. The horse was found to be co-infected with EIAV. Conclusions: The continuous circulation of MADV in Venezuela warrants reinforcing the preventive measures against these alphaviruses, which ignore borders, and may cause important animal and human health concerns.

Hepatitis B virus (HBV) infection is a significant health problem in the world, with around 294 million chronic carriers. Determination of viral load is crucial for the monitoring and treatment follow-up of HBV-infected pa-tients. In-house methods are economical alternatives for those settings where HBV viral load determination might not be widely available commercially. Mo-lecular diagnostic techniques need to take into account the variability of this virus. The aim of this study was the evaluation and optimization of a real-time PCR method for the determination of HBV load. After optimization, the in-house assay evaluated in this study showed acceptable sensitivity and specific-ity, allowing its use for monitoring patients in low-income settings.

Introduction. Previous studies have described an epidemic of HIV-1 in the indigenous Warao population living in the Orinoco Delta, Venezuela. The Warao face extraordinary challenges amid of their ongoing HIV-1 epidemic, the highest reported HIV-1 prevalence in indigenous groups (9.6%) in South America.Objective. To investigate the antibody reactivity to HIV-1 synthetic peptides in seropositive individuals, with a particular focus on the indigenous Warao population from Venezuela. Materials and methods. The HIV-1 Pol region from infected patients’ isolates was amplified, sequenced, and analyzed using phylogenetic tools. Custom-designed synthetic peptides were derived from conserved regions of HIV-1 glycoproteins 41 and 120, based on reference sequences. Multiple antigen blot assays were used to evaluate the presence of antibodies against synthetic peptides.Results. The most frequent HIV-1 subtype was B, the most common in Venezuela, although some individuals were infected with subtype A1. Distinct patterns of reactivity to synthetic peptides were observed between the sera of the general population and the Warao population; the sera of the latter exhibited a high intensity of peptide recognition.Conclusions. The use of synthetic peptides, coupled with the robust performance of multiple antigen blot assays, enriches our understanding of antibody responses in different HIV-1-infected populations.

Avian influenza subtype H5N1 has caused outbreaks worldwide since 1996, with the emergence of the Guandong lineage in China. The current clade 2.3.4.4b has evolved from this lineage, with increased virulence and mass mortality events in birds and mammals. The objective of this study was the analysis of 17 viral genomes of H5N1 avian influenza isolated in Venezuela during the 2022–2023 outbreak. The eight viral genomic segments were amplified using universal primers and sequenced via next-generation sequencing. The sequences were analyzed to confirm the H5 hemagglutinin clade, identify possible genetic reassortments, and perform a phylogenetic and docking analysis of the viral isolates. The viruses found in Venezuela belonged, as expected, to clade 2.3.4.4b and formed a monophyletic clade with North American influenza viruses, with no evidence of further reassortment. The introduction of the virus in South America is associated with bird migration through the Atlantic (Venezuela), Atlantic/Mississippi (Choco, Colombia), and Pacific migratory flyways, with the emergence of several viral lineages. Several mutations were found in all segments of the genome, although none of the key mutations was involved in mammalian adaptation. Moreover, in silico structural analysis suggests, as expected, that the viral hemagglutinin maintained a predilection for avian α2,3-linked sialic acid. The unprecedented pathogenic outbreak of avian influenza disease in South America was associated with the circulation of three different lineages, which maintain a lower affinity for the mammalian receptor.

Mpox (formerly known as monkeypox) is an infectious disease caused by MPXV, a member of the family Poxviridae. On July 23, 2022, the WHO declared the first Public Health Emergency of International Concern of Mpox due to an escalating global outbreak with low intensity. Two clades of MPXV and sev-eral lineages within each of these clades have been described. Clade I, also known as the Central African clade, causes a more severe and lethal disease than clade II, which circulates in West Africa. MPXV clade IIb caused the first international outbreak (2022), while clade Ib caused a more recent one (2023-2024). Venezue-la reported 12 cases during the 2022-2023 outbreak. This study aims to describe the epidemiological and virological characteristics of these cases. The first three cases were from men infected outside Venezuela, while most of the subsequent ones were from men who acquired the disease in the country. All the cases were from men who have sex with men, and frequently also people living with HIV-1/AIDS. No critical outcome was observed in any of the patients. Sequence analysis showed that most of the MPXV belonged to clade IIb lineage B.1. The recurrent emergence of mpox epidemics warrants the further implementation of molecular epidemiology surveillance and vaccination programs.

The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion of the host neutralizing antibodies. Some of the viral lineages derived from this evolution have been classified as Variant of Interest (VOI) or Concern (VOC). The neutralizing capacity of a F(ab′)2 preparation from sera of horses immunized with viral RBD was evaluated by lytic plaque reduction assay against different SARS-CoV-2 variants. A F(ab′)2 preparation of a hyperimmune serum after nine immunizations with RBD exhibited a high titer of neutralizing antibodies against the ancestral-like strain (1/18,528). A reduction in the titer of the F(ab’)2 preparation was observed against the different variants tested compared to the neutralizing activity against the ancestral-like strain. The highest reduction in the neutralization titer was observed for the Omicron VOC (4.7-fold), followed by the Mu VOI (2.6), Delta VOC (1.8-fold), and Gamma VOC (1.5). Even if a progressive reduction in the neutralizing antibodies titer against the different variants evaluated was observed, the serum still exhibited a neutralizing titer against the Mu VOI and the Omicron VOC (1/7113 and 1/3918, respectively), the evaluated strains most resistant to neutralization. Therefore, the preparation retained neutralizing activity against all the strains tested.

The Receptor Binding Domain (RBD) of SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is the functional region of the viral Spike protein (S), which is involved in cell attachment to target cells. The virus has accumulated progressively mutations in its genome, particularly in the RBD region, many of them associated with immune evasion to the host neutralizing antibodies. Some of the viral lineages derived from this evolution, have been classified as Variant of Interest (VOI) or Concern (VOC). The neutralizing capacity of a F(ab’)2 preparation from sera of horses immunized with viral RBD was evaluated, by lytic plaque reduction assay, against different SARS-CoV-2 variants. A F(ab’)2 preparation of an hyperimmune serum with 15 immunizations with RBD, exhibited a high titer of neutralizing antibodies against the ancestral-like strain (1/18,528). A reduction in the title of the F(ab’)2 preparation was observed against the different variants tested. The highest reduction was observed for the Omicron VOC (4.7 fold), followed by the Mu VOI (2.6), Delta VOC (1.8 fold) and Gamma VOC (1.5). Even if a progressive reduction in the neutralizing antibodies titer against the different variants evaluated was observed, the serum still exhibited a significant neutralizing titer, against the Mu VOI and the Omicron VOC (1/7113 and 1/3918 respectively), the strains evaluated most resistant to neutralization.