Hepatitis E virus (HEV) infects several animal species that act as zoonotic reservoirs for viral transmission. Solid and liquid residues from infected animals could lead to HEV contamination of food and surface waters. Evidence of human HEV infection through ingestion of seafood (shellfish, mussels) has been reported. Dolphins generally feed on fish and squid but are able to adapt to an environment and consume whatever prey is available. Clinical signs of infected dolphins include lethargy, inappetence, behavioral aberrations and increased serum alanine aminotransferase (ALT). The dolphins examined in this study were maintained at the National Aquarium, Havana, Cuba. A total of 31 dolphins were evaluated for HEV markers. Sera were collected and screened for total immunoglobin (Ig) anti-HEV. Sera and liver homogenate were tested for HEV RNA by nested RT-PCR using primers targeting the open reading frame 1. Phylogenetic analysis was performed using partial nucleotide sequences at the amplified RNA-dependent RNA polymerase gene. Total anti-HEV Ig was detected in 32.2% (10 of 31), and 16.1% (5 of 31) of these dolphins were positive by both serology and HEV RNA testing. Nucleotide sequence analyses revealed that HEV strains identified in dolphins were genotype 3. This virus may represent an environmental contamination of food or wastewater as a source of HEV exposure and infection. Our findings provide evidence that HEV is associated with liver disorders in cetaceans and that it is advisable to screen for exposure of this virus in captive dolphins, particularly animals with elevated serum ALT or compromised liver function test results of undetermined cause.

Hepatitis E virus (HEV) infection is an important cause of acute viral hepatitis in tropical and sub-tropical regions that occurs both as epidemic episodes and sporadic cases. The aim of this investigation was to estimate the prevalence of total immunoglobulin (Ig) anti-hepatitis E virus (anti-HEV) and the risk factors associated to two communities in Havana City. Serum samples (n=469) obtained from healthy individuals with no history of viral hepatitis were screened for total anti-HEV by enzyme immunoassay (EIA). An overall prevalence of 10% (47/469) (95% CI; 7.52-13.19%) was obtained. Higher anti-HEV prevalence was found in the municipality of Marianao (12.1%) compared to Playa (7.1%). Analysis of risk factors revealed a significant association of total anti-HEV prevalence in age group 41-60 years old, with a risk ratio of 3.21 (95% CI: 1.09-9.7) (P=0.01). No relation was found between anti-HEV and other variables such as gender, risk occupations, surgery and transfusions. The detection of total anti-HEV in individuals with no overt acute hepatitis suggests the existence of sub-clinical or anicteric HEV infection in these municipalities.

Cuba is an HBsAg low-prevalence country with a high coverage of anti-hepatitis B vaccine. Its population is essentially the result of the population mix of Spanish descendants and former African slaves. Information about genetic characteristics of hepatitis B virus (HBV) strains circulating in the country is scarce. The HBV genotypes/subgenotypes, serotypes, mixed infections, and S gene mutations of 172 Cuban HBsAg and HBV-DNA positive patients were determined by direct sequencing and phylogenetic analysis. Phylogenetic analysis of HBV S gene sequences showed a predominance of genotype A (92.4%), subgenotype A2 (84.9%) and A1 (7.6%). Genotype D (7.0%) and subgenotype C1 (0.6%) were also detected but typical (sub)genotypes of contemporary West-Africa (E, A3) were conspicuously absent. All genotype A, D, and C strains exhibited sequence characteristics of the adw2, ayw2, and adrq serotypes, respectively. Thirty-three (19.1%) patients showed single, double, or multiple point mutations inside the Major Hydrophilic domain associated with vaccine escape; eighteen (10.5%) patients had mutations in the T-cell epitope (amino acids 28-51), and there were another 111 point mutations downstream of the S gene. One patient had an HBV A1/A2 mixed infection. This first genetic study of Cuban HBV viruses revealed only strains that were interspersed with strains from particularly Europe, America, and Asia. The absence of genotype E supports previous hypotheses about an only recent introduction of this genotype into the general population in Africa. The presence of well-known vaccine escape (3.5%) and viral resistance mutants (2.9%) warrants strain surveillance to guide vaccination and treatment strategies.