Boid inclusion body disease in Boa constrictor: Unraveling the myth of immunosuppression

Boid inclusion body disease (BIBD) is an infectious disease of captive boid snakes of major relevance since the 1970s. It is caused by reptarenaviruses and characterized by intracytoplasmic inclusion bodies in most cell types. Affected snakes frequently develop secondary bacterial infections, suggesting virus-associated immunosuppression. To investigate this, we analyzed peripheral blood from 48 Boa constrictor with confirmed BIBD, three infected snakes without disease, and 84 reptarenavirus-negative snakes, assessing hematology, biochemistry, stress parameters, and immune function. A functional phagocytosis assay on peripheral blood revealed a significantly reduced proportion of phagocytic cells (Iba1⁺ monocytes/azurophils) in BIBD-positive and reptarenavirus-infected snakes compared to uninfected animals, indicating impaired phagocytic capacity. In addition, BIBD-positive snakes showed reduced cholesterol and total immunoglobulin concentrations, while virus-specific IgY and IgM levels were elevated. These findings indicate selective impairment of innate and humoral immune components, providing mechanistic evidence for increased susceptibility to secondary bacterial infections in BIBD.

University of Helsinki
Universität Zürich
Leibniz-Institut für Zoo- und Wildtierforschung