From the Guidelines
To evaluate for hepatitis B in a tiger, veterinarians should perform a comprehensive blood panel including liver enzymes (ALT, AST, ALP), complete blood count, and specific hepatitis B virus (HBV) testing, as true hepatitis B virus infection as seen in humans is not naturally occurring in tigers, but testing is still necessary to rule out other causes of hepatitis 1. The testing should include PCR assays to detect viral DNA and serological tests for antibodies if available for tiger species.
- Liver function tests will help assess organ damage,
- Ultrasound imaging of the liver may be necessary to evaluate structural changes. Blood samples should be collected under sedation by a qualified veterinarian and sent to a specialized wildlife or veterinary diagnostic laboratory with experience in exotic animal testing. Interpretation requires expertise in tiger physiology as normal reference ranges differ significantly from humans. If hepatitis is confirmed, treatment would be supportive care including fluid therapy, nutritional support, and possibly antiviral medications adapted for tiger metabolism under close veterinary supervision, as the primary goal is to reduce morbidity, mortality, and improve quality of life 1. It is essential to note that the initial evaluation of patients with chronic HBV infection should include a thorough history and physical examination, with special emphasis on risk factors for coinfection, alcohol use, and family history of HBV infection and liver cancer, although this may not be directly applicable to tigers, the principle of thorough evaluation remains crucial 1. The use of HBV DNA assays, such as those based on polymerase chain reaction (PCR) amplification, can help in the evaluation of patients with chronic HBV infection and in the assessment of the efficacy of antiviral treatment, but the application of these tests in tigers would require species-specific validation 1. In the context of hepatitis B evaluation in tigers, it is critical to prioritize the most recent and highest quality studies, even though the majority of the evidence is focused on human hepatitis B, the principles of comprehensive evaluation and supportive care can be adapted to veterinary practice, with a focus on minimizing morbidity, mortality, and improving quality of life 1.
From the Research
Hepatitis B Diagnosis and Laboratory Tests
- The diagnosis of hepatitis B virus (HBV) infection involves various serologic- and molecular-based methods, including the detection of hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), and hepatitis B virus DNA 2.
- New biomarkers such as hepatitis B virus core-related antigen (HBcrAg) and HBV RNA have emerged, which appear to reflect intrahepatic covalently closed circular DNA (cccDNA) status and may be useful in monitoring treatment response [(2,3)].
Protection Against HBV Infection
- The presence of hepatitis B surface antibody (anti-HBs) in addition to anti-HBc may confer protection against HBV infection in HBsAg-negative patients undergoing kidney transplantation 4.
- A higher level of anti-HBc is associated with a lower risk of HBV DNA undetectability and HBsAg seroclearance in HBeAg-seronegative patients 5.
Predicting Clinical Relapse
- The combination of end-of-treatment HBcrAg and HBV RNA levels is most predictive of clinical relapse after nucleos(t)ide analogue therapy discontinuation 3.
- Patients with undetectable HBcrAg and HBV RNA at the end of treatment are less likely to develop clinical relapse 3.