A comparative study of Trypanosoma sp. (Protozoa: Kinetoplastida) parasitizing four species of loricarides in the Brazilian Amazon

Trypanosomes are flagellate hemoparasites that infect a wide variety of vertebrates, with neotropical freshwater fish of the Loricariidae family among their known hosts. The present study describes the morphometry of three morphotypes of Trypanosoma sp. parasites of four species of loricariids in the Brazilian Amazon. Between April and May 2018, 28 specimens of Pterygoplichthys pardalis were captured in Pacoval Lake and one specimen of Hypostomus sp., one specimen of Squaliforma sp. and one representative of Lamontichthys cf. stibaros were collected from the mouth of the Tapajos River, in an area known as Enseada Grande, located in the municipal region of Santarem, in the west of the state of Para, Brazil. A blood sample was collected by cardiac puncture and smears were prepared. The trypanosomes were photographed to allow morphometry to be carried out. The specimens of Squaliforma sp., Lamontichthys cf. stibaros and Hypostomus sp. exhibited infection with trypanosomatids whereas of the 28 specimens of P. pardalis, only five were infected by Trypanosoma sp., representing a prevalence of 17.86%, with a mean infection intensity of 11 x 10(4) parasites/mL and an average abundance of 0.37. The presence of three morphological types of Trypanosoma sp. infecting the Loricariids was identified. Morphotype A was identified infecting P. pardalis and L. cf. stibaros, morphotype B infected Squaliforma sp. and Hypostomus sp. and morphotype C infected only L. cf. stibaros. Mixed infection by morphotypes A and C was observed in L. cf. stibaros.