Strongyloidiasis is an intestinal parasitic infection of the nematodeStrongyloides, 1 which is a parasite of animals in both free-living conditions and captivity. 2,3 The species S. fuelleborni and S. cebus are parasites of Old and New World primates, respectively. Human infections of S. stercolaris are frequent, but zoonotic or anthropozoonotic infections can also occur. 4 Among Old World primates, Erythrocebus patas have shown histopathological lesions caused by S. stercoralis manifesting as disseminated hyperinfection, severe necrotizing duodenitis, colitis, and pulmonary hemorrhage. 5 Among Neotropical primates, pot-bellied Lagothrix cana monkeys have shown severe Strongyloides infections manifesting as hemorrhage and lesions in the lung, duodenum, and jejunum with mucosal erosion, and presence of larvae. 6 This infection occurs by penetration of the filarioid larvae through feet or hands, reaching derma, and subsequently, lymphatic and blood circulation. It can also occur through ingestion of water and food contaminated with filarioid larvae.In Strongyloides infections, third-stage self-infecting larvae can promote severe hyperinfection resulting from the exacerbation of the autoinfection cycle, manifesting with diarrhea, malabsorption, and acute enteritis in primates. 6 This infection can accelerate pathological processes that are already established, such as wasting marmoset syndrome (WMS), and can lead to quick death, particularly in babies of non-human primates. The aim of this study was to describe the anatomopathological aspects of disseminated strongyloidiasis in three captive callitrichids.