Hepatitis E virus in bottlenose dolphins Tursiops truncatus

Abstract

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.

Cyanobacterial neurotoxin BMAA and brain pathology in stranded dolphins

“…Gross examinations of internal structures were unremarkable, except for two dolphins (14%) with non-specific lung (Hubbs 0541 Tt) and spleen (IFAW12-198Dd) pathology. One dolphin had signs of hepatitis (IFAW12-201Dd) [48].…”

“…At necropsy, external and internal examinations were performed and tissue samples were collected for histopathology and infectious disease testing (Morbillivirus, Brucella spp., etc. [48]) where available (S1 Table). Brains from the Massachusetts’ cohort (n = 7 dolphins) were harvested, and a mid-sagittal cut was made to separate each brain into right and left hemispheres.…”

Hepatitis E virus and related viruses in wild, domestic and zoo animals: A review

“…Very recently, evidence for HEV infection in dolphins, maintained in a National Aquarium in Cuba, was described (Montalvo Villalba et al., ). The authors found HEV‐specific antibodies in 10 of 31 (32%) and HEV‐3‐RNA in 5 of 31 (16%) of the animals.…”

Challenges in research and management of hepatitis E virus infection in Cuba, Mexico, and Uruguay

“…Phylogenetic analysis shows that human and swine HEV strains are closely related, with 94%-99% nucleotide sequence identity. Furthermore, seroconversion and HEV-G3b have been recently identified in bottlenose dolphins (Tursiops truncates) in Cuba (13), but the clinical relevance of this infection requires further investigation. Thus, zoonotic HEV-G3 and epidemic HEV-G1 strains seem to co-circulate in Cuba.…”

“…HEV-G4 is almost exclusively restricted to Asia (3,4,7). HEV genotypes and reservoirs from nine LAC countries (Argentina, Bolivia, Brazil, Colombia, Costa Rica, Cuba, Mexico, Uruguay, Venezuela) (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) are shown in Table 1. Specific clinical manifestations of HEV infection have been tentatively associated with distinct genotypes; for example, HEV-G1 is related to fulminant acute hepatitis in pregnancy, whereas HEV-G3 is associated with chronic liver disease in immunosuppressed patients (2,7).…”