Evaluation of HBV-Like Circulation in Wild and Farm Animals from Brazil and Uruguay

Abstract

The origin of the hepatitis B virus is a subject of wide deliberation among researchers. As a result, increasing academic interest has focused on the spread of the virus in different animal species. However, the sources of viral infection for many of these animals are unknown since transmission may occur from animal to animal, human to human, animal to human, and human to animal. The aim of this study was to evaluate hepadnavirus circulation in wild and farm animals (including animals raised under wild or free conditions) from different sites in Brazil and Uruguay using serological and molecular tools. A total of 487 domestic wild and farm animals were screened for hepatitis B virus (HBV) serological markers and tested via quantitative and qualitative polymerase chain reaction (PCR) to detect viral DNA. We report evidence of HBsAg (surface antigen of HBV) and total anti-HBc (HBV core antigen) markers as well as low-copy hepadnavirus DNA among domestic and wild animals. According to our results, which were confirmed by partial genome sequencing, as the proximity between humans and animals increases, the potential for pathogen dispersal also increases. A wider knowledge and understanding of reverse zoonoses should be sought for an effective One Health response.

Seroprevalence of canine hepatitis in stray dogs in Nineveh Province, Iraq

“…This result is in line with the study of Vieira et al . [ 6 ] where 5.8% of dogs tested positive. The seropositivity in the current study could reflect HBV or HBV-like virus infections.…”

“…The seropositivity in the current study could reflect HBV or HBV-like virus infections. One reason is that dogs could be exposed to the HBV infection from the environment potentially contaminated by infected humans [ 6 , 10 ]. Another reason is that the seropositive reaction is due to HBV-like virus that is adopted to infect dogs.…”

“…Hepatitis B virus (HBV) is a hepatotropic DNA virus belongs to the family: Hepadnaviridae, genus: Orthohepadnavirus, and classified into four serotypes with 10 genotypes including different subtypes [ 1 , 2 ]. Although HBV infection requires species-specific host factors [ 3 , 4 ] and mainly affects human, the HBV and HBV-like virus can infect different types of mammals including chimpanzees, gibbons, gorillas, orangutans, woolly monkeys, pigs, and squirrels, with potential cross-species transmission among different hosts [ 5 , 6 ]. Recently, HBV-like virus has been identified in domestic cats [ 7 ].…”

“…However, in a study tested serum samples of different animal species for hepatitis B surface antigen, hepatitis B surface antibody, and antibody against hepatitis B core antigen using radioimmunoassays, dogs were among animals that showed positive reaction for hepatitis B surface antibody [ 10 ]. In a more recent study, 10% and 5.8% of tested domestic dogs showed positive reaction for antibody against hepatitis B core antigen and hepatitis B surface antigen, respectively, using enzyme-linked immunosorbent assay (ELISA) for serum samples [ 6 ]. In that study, the molecular tests indicated that 10% of domestic dogs were positive for the pre-S/S gene of HBV.…”

“…On the other hand, stray dogs are common even inside urban areas. In this situation, if a cross-species transmission among different hosts is existed in HBV [ 5 ], and dogs are potentially infected with HBV or HBV-like virus [ 6 ], investigation of HBV in dogs is important. To the best of our knowledge, no study has investigated HBV infection in dogs in Nineveh Province, Iraq.…”