Phylogeny and Pathology of Anisakids Parasitizing Stranded California Sea Lions (Zalophus californianus) in Southern California

In marine mammals, nematode-inflicted pathological lesions combined with other pathogens and factors (i.e., pollution, climate change, domoic acid poisoning events, seasonal El Nino starvation events) negatively impact pinnipeds’ health may cause mortality. Five California sea lions ( Zalophus californianus )—a female pup, three male yearlings, an adult female—suffered mortalities during rehabilitation at the Marine Mammal Care Center Los Angeles (San Pedro, CA). According to necropsy reports, animals developed multisystemic parasitism as a leading of death, malnutrition hypoglycemia. order reveal host–parasite dynamics that play role in pinniped recovery, we examined type level histopathological stomach caused by anisakid nematodes. All isolated anisakids were morphologically molecularly identified, their phylogenetic relationships reconstructed using sequence mitochondrial COII gene. Co-parasitation different Anisakidae spp. within same host or presented opportunity evaluate existence recombinant haplotypes eventual pressure exerted onto host. The chronic granulomatous gastritis, moderate edema hyperemia tunica submucosa lamina propria, followed mild, focal fibrosis gastric wall. Ulcerative changes mixed leukocytic infiltrate showed be localized, shallow, non-perforative no apparent bacterial coinfection, mostly accompanied healing granulation tissue. Isolated are grouped into distinctively separated monophyletic clades corresponding genera Anisakis , Contracaecum Pseudoterranova . Most abundant representatives ogmorhini sensu lato (55.36%), pegreffii (23.21%), azarasi (17.86%), decipiens (1.79%), simplex (1.79%). Phylogenetic trees revealed differentiation intra-species level. Our analysis divergence from lineages Jurassic period 176.2 Mya diverging Cenozoic 85.9 Mya.