Baylisascaris potosis, Tokiwa, Nakamura, Taira & Une, 2014

Sapp, Sarah G. H., Gupta, Pooja, Martin, Melissa K., Murray, Maureen H., Niedringhaus, Kevin D., Pfaff, Madeleine A. & Yabsley, Michael J., 2017, Beyond the raccoon roundworm: The natural history of non-raccoon Baylisascaris species in the New World, International Journal for Parasitology: Parasites and Wildlife 6 (2), pp. 85-99 : 95

2.6. Baylisascaris potosis

A novel Baylisascaris species, B. potosis , was recently described in kinkajous ( Potos fl avus). Type specimens were collected from captive kinkajous that originated in Cooperative Republic of Guyana ( Tokiwa et al., 2014). This species is morphologically similar to B. procyonis but was described as a new species based on genetic analysis of several gene targets (i.e., internal transcribed spacer (ITS) 2 region, 28S rRNA gene, and COX1 gene) ( Taira et al., 2013; Tokiwa et al., 2014). Kinkajous are common exotic pets in the United States and other countries.

Previously, kinkajous were reported as a host of B. procyonis , both in the wild in Columbia and in captivity in the United States and Japan ( Overstreet, 1970; Kazacos et al., 2011; Taira et al., 2013; Parzansky, 2015). Another possible host, the bushy-tailed olingo ( Bassaricyon gabbii ) passed a male Baylisascaris (reported as B. procyonis ) after being fed eggs from a naturally-infected kinkajou from Columbia; however, it is not known if the olingo was infected prior to the experiment ( Overstreet, 1970). However, since the description of B. potosis , these reports are questionable, and where possible should be confirmed with molecular data.

To evaluate possibile paratenic hosts that can develop larva migrans, Tokiwa et al. (2015a), experimentally inoculated Mongolian gerbils. Exposure of gerbils to 100‾4000 embryonated eggs resulted in VLM, but no larvae were found in the brain. A squirrel monkey ( Saimiri sciureus ) inoculated with 10,000 B. potosis eggs did not develop clinical signs or gross lesions, although a few migrating larvae were recovered from liver and kidney tissues ( Tokiwa et al., 2015b). Another squirrel monkey inoculated with 100,000 eggs in the same trial developed gross lesions, including liver congestion, pulmonary edema, and abundant intestinal granulomas. Small granulomatous lesions containing larvae were found in the outer layers of the cerebral cortex, without deeper invasion as is typical of B. procyonis . This animal was found dead at 30 DPI, but the animal lacked clinical signs and the authors state that no cause of death was determined. However, pulmonary edema, liver congestion, and nodular lesions containing non-degenerate larvae along the intestine were found at necropsy ( Tokiwa et al., 2015b). Based on these preliminary trials, it appears that B. potosis can cause larva migrans in rodent and primate hosts, although the pathogenicity and capacity for neural invasion appears less than that of B. procyonis or B. columnaris .

Because of the recent description of this parasite and the paucity of surveillance in possible hosts in South America apart from a single infected individual, little is known about the natural history of B. potosis . Interestingly, raccoons were recently confirmed to have B. procyonis infections, based on sequence analysis, in Costa Rica ( Baldi et al., 2016). It appears that B. procyonis and B. potosis are sympatric in procyonids in Central America, highlighting the need for additional research to understand these closely related parasites that may share hosts.