Effects of Goussia infecting the blue whiting and phylogenetic placement of Goussia infecting marine fish off Northern Portugal.

Coccidian parasites of fish have received considerably less attention than their terrestrial counterparts, and within piscine hosts, most studies have focused on freshwater fish. The present study aimed to describe oocyst morphology, phylogenetic affinities, and the impacts of coccidian parasites infecting the internal organs of a commercially valuable marine fish, the blue whiting (Micromesistius poutassou), captured off the Portuguese coast. As part of the phylogenetic analysis, sequences from coccidians infecting the pout (Trisopterus luscus) and the Atlantic chub mackerel (Scomber colias) were included, and the oocyst morphology of the coccidians infecting the former was also reported. Results showed that the prevalence of coccidiosis in the blue whiting was very high (> 82%), occurring in all analyzed organs, despite being more abundant in the liver. A significant negative correlation was found between the abundance of the parasites in the liver and host condition index (p < 0.05), which indicates a negative effect on the fitness of this host. Phylogenetic analyses of the parasites found in all three species examined identified three different species of Goussia, closely related to Goussia clupearum. Adding to previous research, we propose the existence of a fourth group of Goussia, the clupearum type, able to infect multiple organs and phylogenetic related with G. clupearum.

[Goussia obstinata sp. n. (Sporozoa: Eimeriidae), a new coccidian species from intestines of the Amur sleeper Perccottus Glenii Dybowski, 1877 (Perciformes: odontobutidae)].

Goussia obstinata sp. n. is described from the intestine epithelium of the Amur sleeper Perccottus glenii Dybowski, 1877 from Russia and Moldova. The species was examined in an optical microscope. Merogonic, gamogonic and sporogonic stages of the species are located in cells of the gut epithelium. Sporulation is endogenous; oocysts are released in the gut lumen. Non-sporulated oocysts are spherical or ellipsoidal; sporulated oocysts are rounded, 6.7-11.4 µm in diameter, with a colorless, single-layer, very fine and easily ruptured wall. Micropyle and oocyst residuum is absent; 1-2 small polar granules of 1.0-2.5 µm are sometimes present. Oocysts contain four compact widely oval, slightly narrow-ended sporocysts. The sheath of the sporocyst is formed of two folds divided by a slightly S-shaped longitudinal suture. Coarsely granulated, globular or oval compact sporocyst's residuumis located between sporozoites. Sausage-shaped sporozoits are subdivided by a bend into two unequal parts, being 6.4-9.8 µm (long part) and 2.6-4.8 µm (short part) long, arranged in a top-to-tail position. Our preliminary data suggests that infestation of the sleeper with the examined parasite is not associated with the morbidity and mortality of the fish. A new combination Goussia marmorata (Molnár, 1996) comb. n. is proposed for a species originally described in the content of the genus Eimeria Schneider, 1875 from the Western tubenose goby Proterorhinus semilunaris.

Ultrastructural aspects of hepatic coccidiosis caused by Goussia lusca n. sp. (Apicomplexa: Coccidia) infecting Trisopterus luscus (Gadidae) from the NE Atlantic Ocean.

Goussia lusca n. sp. is described from the liver of pouting Trisopterus luscus from the NE Atlantic Ocean in Ibero-Atlantic Portuguese and Spanish waters. Mature oocysts were 31.7 (28.8 to 35.4) microm in diameter. Each oocyst contained 4 ellipsoidal sporocysts arranged in an aleatory position, and measuring approximately 13.7 x 9.2 microm. Each sporocyst contained 2 sporozoites. Ultrastructurally, the sporocyst wall consisted of a dense inner layer 115 nm thick, transversely striated, regularly intercalated by thin grooves with electron-lucent spaces, and separated from the outer layer by a thin, light (electron-lucent) space. The outer layer was multilamellated and consisted of parallel dense bands alternating with light spaces. These lamellae formed filamentous extensions of the wall. The dehiscence suture, a characteristic feature of the genus, was present in the sporocysts. No external clinical signs were observed in the host fish. Parasites observed in the liver tissue were often enveloped in a yellowish-brown matrix, generally known as 'yellow bodies'. Sometimes sporocysts were observed in direct contact with the liver cells. Parasites in degeneration and aggregations of amylopectin granules were frequently observed surrounded by host inflammatory cells. In severe infections, we observed large agglomerations of oocysts encapsulated by layers of concentrically arranged connective tissue forming large granulomas, which caused significant replacement of the host liver parenchyma by the parasite.

Extra-intestinal localization of Goussia sp. (Apicomplexa) oocysts in Rana dalmatina (Anura: Ranidae), and the fate of infection after metamorphosis.

Although coccidia of the genus Goussia are common parasites of fish, only 2 species have been described in amphibians: G. hyperolisi from common reed frogs Hyperolius viridiflavus from Kenya and G. neglecta from unspecified European water frogs of the genus Rana from Germany. The genus Goussia is characterized by an oocyst, with a fine oocyst wall, containing 4 dizoic sporocysts that are composed of 2 valves joined by a longitudinal suture and lacking a Stieda body (typical for the genus Eimeria). To date, infections in amphibians were generally considered to be specific to the intestine of aquatic larval stages (tadpoles) of anurans. Herein, we report on: (1) the presence of oocysts of Goussia sp. in an extra-intestinal location (liver) of tadpoles of the agile frog R. dalmatina and (2) the presence of oocysts in the liver of both juvenile and subadult R. dalmatina. These observations represent novel traits for Goussia infections in amphibians; they may explain the vertical transmission of Goussia in tadpoles.

Invasion of different cell types by sporozoites of Eimeria species and effects of monoclonal antibody 1209-C2 on invasion of cells by sporozoites of several apicomplexan parasites.

Sporozoites of avian Eimeria species differed markedly in their ability to invade cells in vitro. Invasion by E. tenella and E. adenoeides was significantly greater in baby hamster kidney (BHK) and chicken cecal cell (CC) cultures than in primary chicken (PCK) or turkey kidney (PTK) cell cultures. Moreover, invasion of BHK cell cultures by E. adenoeides was significantly greater than that of other Eimeria species, and invasion by E. acervulina sporozoites was significantly lower. Monoclonal antibody 1209-C2 (MAb 1209-C2) reacted by immunofluorescent labeling (IFA) with refractile bodies of sporozoites of 5 species of Eimeria and Caryospora bigenetica, but not with sporozoites of Toxoplasma gondii, Hammondia hammondi, or Cryptosporidium parvum, which have no refractile bodies. The MAb also cross-reacted with formalin-fixed BHK, CC, turkey cecal (TC) cells, and PTK. Pretreatment of BHK cells with MAb 1209-C2 significantly reduced invasion of the cells by sporozoites of E. tenella, E. acervulina, E. meleagrimitis, and C. bigenetica, but did not alter invasion by T. gondii, C. parvum, or H. hammondia. Apparently, reactivity of MAB 1209-C2 with the sporozoites was required for inhibition of invasion despite the fact that the inhibition resulted from pre-treatment of the host cell. Conversely, although MAb 1209-C2 also reacted moderately with PTK and TC cells, pre-treatment of these cell cultures with the MAb did not inhibit invasion by either MAB 1209-C2-reactive or -nonreactive parasites. Collectively, the data indicated that refractile body antigens of sporozoites of Eimeria and Caryospora, which are recognized by MAb 1209-C2, may function in cellular invasion, but also suggest that cellular invasion is probably not mediated by interactions between the conserved epitopes in sporozoites and cultured host cells that are recognized by the MAb.