Goussia alosii, Lovy & Friend, 2015

Lovy, Jan & Friend, Sarah E., 2015, Intestinal coccidiosis of anadromous and landlocked alewives, Alosa pseudoharengus, caused by Goussia ameliae n. sp. and G. alosii n. sp. (Apicomplexa: Eimeriidae), International Journal for Parasitology: Parasites and Wildlife 4 (2), pp. 159-170 : 167

Goussia alosii n. sp. ( Fig. 4 , 5C )

Family: Eimeriidae Minchin, 1903 .

Genus: Goussia Labbe, 1986 .

Type host: Alosa pseudoharengus (Wilson, 1811) , landlocked form, YOY and adult fish.

Other hosts: unknown.

Type locality: Lake Hopatcong , New Jersey, USA .

Other localities: unknown.

Type material: Photomicrographs of fresh preparations, histological sections and blocks are catalogued at the New Jersey Division of Fish and Wildlife Fish Pathology Laboratory, Oxford, NJ 07863, USA .

Parasite description: Unsporulated oocysts elongated and ovoid in shape (length = 21.38 ± 1.99 μm, width = 9.79 ± 0.80 μm, n = 30) ( Fig. 4A ). Oocyst wall in sporulated oocysts is thin, but thicker than that of G. ameliae . Oocyst wall smooth and regular, forming an ovoid shape ( Fig. 4B ). Micropyle, oocyst residuum and polar granule absent. Each oocyst with four highly elongated sporocysts that are over 3× as long as they are wide ( Fig. 4B ). Refer to Table 1 for measurements of oocysts and sporocysts; line drawing of sporulated oocysts in Fig. 5C . In histology, parasite stages found in intestinal epithelium with early stages, macrogamonts, and microgamonts localized in an epicellular position ( Fig. 4C ). The intestinal epithelium is concaved in areas where the parasite is positioned and an apparent membrane covers the macrogamonts. Elongated, unsporulated oocysts in the intestinal epithelium in an epicellular position or deeper within the epithelium ( Fig. 4D ) and within fecal casts ( Fig. 4E ).

Infection site: Mid to lower intestinal tract, found posterior to pyloric cecum.

Prevalence: 49% in YOY fish and 14% in adult fish (1+ year old). Dual infection with the more prevalent G. ameliae often occurred.

Pathology: Majority of infections were light, with little to no pathology associated. Few heavy infections were characterized by a heavy covering of epicellular parasite stages throughout the intestinal epithelium. Sloughing of intestinal epithelium with unsporulated oocysts forming mucoid casts in the intestinal lumen.

Etymology: The name is derived from the genus of the host Alosa , from which the coccidian was found.

Figures

Fig. 4. Goussia alosii from the intestine of landlocked alewives, bar = 10 μm. Wet mount of (A) highly elongated unsporulated oocysts and (B) sporulated oocysts with a thicker oocyst wall making up a very regular oval shape containing four highly elongated sporocysts. (C–E) Histology of coccidial stages in the intestine; (C) various stages of coccidia with an epicellular position within the intestinal epithelium; elongated unsporulated oocysts (arrows) found within the (D) intestinal epithelium and (E) within mucoid casts in the intestinal lumen.

Fig. 5. Line drawings of sporulated oocysts of Goussia ameliae from (A) anadromous and (B) landlocked alewives and (C) G. alosii sampled from landlocked alewives, bar = 5 μm.