Understanding how species once at the threat of extinction are affected in the long term can illuminate current and future conservation concerns. Northern elephant seals (NES) have a unique reaction to a parasitic lungworm. Hunted to a mere 30 individuals, NES have incredibly low genetic diversity. However, they are resilient to viruses and bacteria. The one caveat to their strong immune system is lungworm, which they often die from. 99 NES serum samples were analyzed by enzyme-linked immunosorbent assays (ELISA) using O. circumlitis homogenate. In conjunction with clinical data (blood work, necropsy, treatment, and patient observations) from The Marine Mammal Center, ELISA results were analyzed to discover that some seals are asymptomatic when infected with lungworm. This study offers hope to populations under the threat of extinction that have low genetic diversity.