Co-infections of the cestode Echinococcus vogeli and the nematode Calodium hepaticum in the hystricomorphic rodent Agouti paca from a forest reserve in Acre, Brazil

Abstract

The helminth fauna of Agouti paca (Linnaeus, 1766) has seldom been studied. In this paper, we report an unusual mixed infection of Echinococcus vogeli Rausch & Bernstein, 1972 and Calodium hepaticum (syn. Capillaria hepatica Bancroft, 1863) in free-ranging paca from a forested region in Acre (Brazil). Gross morphological examination revealed that paca liver contained multiple spherical to subspherical white or translucent lesions, which were isolated or frequently contiguous and partially covered by Glisson's capsule. Microscopic examination revealed unilocular cystic structures that contained abundant brood capsules in which numerous protoscolices budded from the inner surface. The protoscolices possessed rostellar hooks (33-41 μm in length), a morphological characteristic of the blade and calcareous corpuscles that is consistent with the metacestode E. vogeli. The diagnosis of C. hepaticum infection was based on the morphology and morphometry of the egg-shaped ellipsoids with bipolar plugs (44.8 ± 1.9 μm (length) × 24.4 ± 2.0 μm (width)) and liver histopathology. This finding expands the known range of C. hepaticum hosts in South America and, to the best of our knowledge, it is the first case of a mixed infection of E. vogeli and C. hepaticum. Furthermore, our data provide evidence that wild animal meat may be a source of C. hepaticum infection.

First molecular identification of Echinococcus vogeli and Echinococcus granulosus (sensu stricto) G1 revealed in feces of domestic dogs (Canis familiaris) from Acre, Brazil

“…In northern Brazil, polycystic echinococcosis has been reported in bush dogs [14, 18], pacas [43, 44] and humans [20, 45]. Although dogs play the double function of companion and hunting (mainly pacas) animals in these communities and are often fed raw paca viscera [14], the presence of E. vogeli has not yet been investigated.…”

Trichuris spp. in Animals, with Specific Reference to Neo-Tropical Rodents

“…This is because the lappe is the intermediate host for Echinococcus spp. [103][104][105][106][107], with the dog as the final host. Humans can become dead-end intermediate hosts following ingestion of eggs shed by dogs, but cannot become infected by meat or organ consumption.…”

Endoparasites of Selected Native Non-Domesticated Mammals in the Neotropics (New World Tropics)

“…were found in the small intestine. Heligmostrongylus agouti and Physocephalus meridionalis were found in the stomach and Echinococcus vogeli and Calodium hepaticum were found in the liver [26,27,39].…”

“…Few studies reported the pathology casued on internal organs by the endoparasites. The liver pathology potentially caused by Echinococcus vogeli and Calodium hepaticum was characterized by fibrosis with a scanty infiltrate of lymphocytes and macrophages [39] and the histopathological lesions of Physocephalus spp. in the stomach showed congestion, interstitial hemorrhaging, and mononuclear inflammatory infiltrates [40].…”