The immune system of [[Lizard|lizards]] and [[Snake|snakes]] is influenced by age, nutrition, general health, ambient temperature and season (refer to [[Snake Physical Examination|snake physical examination]] and [[Snake Housing|snake housing]]). In temperate species thymic involution and splenic follicle regression occur seasonally. Antibody production is temperature dependent. The immune system functions most efficiently within a reptile's [[Preferred optimum temperature zone|preferred optimum temperature zone]] although at a low level in comparison to birds and mammals. In captivity, [[Lizard|lizards]] and [[Snake|snakes]] that are kept below their [[Preferred optimum temperature zone|POTZ]] are immunocompromised and are therefore predisposed to infection with opportunistic pathogens. | The immune system of [[Lizard|lizards]] and [[Snake|snakes]] is influenced by age, nutrition, general health, ambient temperature and season (refer to [[Snake Physical Examination|snake physical examination]] and [[Snake Housing|snake housing]]). In temperate species thymic involution and splenic follicle regression occur seasonally. Antibody production is temperature dependent. The immune system functions most efficiently within a reptile's [[Preferred optimum temperature zone|preferred optimum temperature zone]] although at a low level in comparison to birds and mammals. In captivity, [[Lizard|lizards]] and [[Snake|snakes]] that are kept below their [[Preferred optimum temperature zone|POTZ]] are immunocompromised and are therefore predisposed to infection with opportunistic pathogens. |