Ocular spirorchiidiosis in sea turtles from Brazil

Abstract

The causes of the beaching and death of sea turtles have not been fully clarified and continue to be studied. Mild, moderate and severe lesions caused by spirorchiidiosis have been seen for decades in different organs and were recently defined as the cause of death of a loggerhead turtle. In the present study, eyes and optic nerves were analysed in green sea turtles with spirorchiidiosis and no other debilitating factors. Injuries to the optic nerve and choroid layer were described in 235 animals (90%) infected with spirorchiids. Turtles with ocular spirorchiidiosis are approximately three times more likely to be cachectic than turtles with spirorchiidiosis without ocular involvement.

Serious lesions in Green turtles (Chelonia mydas) afflicted by fatal Spirorchiidiasis found stranded in south and southeastern Brazil

“…Spirorchiidiasis infections are high in marine turtles, globally affecting endangered sea turtle populations, as the Spirorchiidae family is near cosmopolitan in its distribution ( Chen et al, 2012 ; Chapman et al, 2017 , 2019 ; Santoro et al, 2020 ). This parasitic infection has, in fact, been significantly associated to sea turtle stranding and mortality events worldwide ( Santoro et al, 2007 ; Stacy et al, 2010 ; Werneck et al, 2015 ; Jerdy et al, 2020 ).…”

Morphological characterization of fluke eggs in green turtles (Chelonia mydas) found on the coast of Espírito Santo State, Brazil

“…Some studies that microscopically analyzed tissue samples (spleen, lungs, intestine, kidneys, and heart) (Santoro et al 2007b) and fecal samples of C. mydas (Santoro et al 2020) identified eggs similar to types 3 and 4 of this study as corresponding to eggs of spirochiid helminths (Digenea: Spirorchiidae) of the genera Hapalotrema and Neospirorchis, respectively. Jerdy et al (2019) also recorded the observation of spiral-shaped eggs with a circular appearance, similar to species of the genus Neospirorchis, in ocular tissue of C. mydas. Finding helminth eggs of the family Spirorchiidae in the coproparasitological examination reveals important data for the study of the ecology of these parasites, since their life cycle is not yet well elucidated (Chapman et al 2019).…”

“…Algunos estudios que analizaron microscópicamente muestras de tejidos (bazo, pulmones, intestino, riñones y corazón) (Santoro et al 2007b) y muestras fecales de C. mydas (Santoro et al 2020) identificaron huevos similares a los tipos 3 y 4 de este estudio como correspondientes a huevos de helmintos espiroquidos (Digenea: Spirorchiidae) de los géneros Hapalotrema y Neospirorchis, respectivamente. Jerdy et al (2019) también registraron la observación de huevos en forma de espiral y apariencia circular, similares a especies del género Neospirorchis, en tejido ocular de C. mydas. El hallazgo de huevos de helmintos de la familia Spirorchiidae en el examen coproparasitológico revela datos importantes para el estudio de la ecología de estos parásitos, ya que su ciclo de vida aún no está bien dilucidado (Chapman et al 2019).…”

Epidemiology of blood flukes (Digenea: Spirorchiidae) in sea turtles from Tyrrhenian and Adriatic Seas, off Italy

“…Our results agree with studies on green turtles from Hawaii [11] and Costa Rica [13,14,28] where although pathological changes by spirorchiid infection were commonly observed, those were rarely considered non-compatible with the life of the host. In contrast, fatal infections have been reported in Florida [5,6], Australia [4,7,8] and Brazil [10].…”

“…To date, a total of 29 marine species belonging to 10 genera have been recognized [1][2][3]. Adult spirorchiids and their eggs may cause a wide range of inflammatory reactions in the vascular system of their host being frequently implicated with stranding and death of sea turtles worldwide [4][5][6][7][8][9][10]. Incidental findings of infection with or no associated diseases have also been described [11][12][13][14][15].…”