Dual congenital transmission ofToxoplasma gondiiandSarcocystis neuronain a late-term aborted pup from a chronically infected southern sea otter (Enhydra lutris nereis)

Abstract

SUMMARYToxoplasma gondiiandSarcocystis neuronaare protozoan parasites with terrestrial definitive hosts, and both pathogens can cause fatal disease in a wide range of marine animals. Close monitoring of threatened southern sea otters (Enhydra lutris nereis) in California allowed for the diagnosis of dual transplacental transmission ofT. gondiiandS. neuronain a wild female otter that was chronically infected with both parasites. Congenital infection resulted in late-term abortion due to disseminated toxoplasmosis.Toxoplasma gondiiandS. neuronaDNA was amplified from placental tissue culture, as well as from fetal lung tissue. Molecular characterization ofT. gondiirevealed a Type X genotype in isolates derived from placenta and fetal brain, as well as in all tested fetal organs (brain, lung, spleen, liver and thymus). This report provides the first evidence for transplacental transmission ofT. gondiiin a chronically infected wild sea otter, and the first molecular and immunohistochemical confirmation of concurrent transplacental transmission ofT. gondiiandS. neuronain any species. Repeated fetal and/or neonatal losses in the sea otter dam also suggested thatT. gondiihas the potential to reduce fecundity in chronically infected marine mammals through parasite recrudescence and repeated fetal infection.