No abstract

S U M M A R YMore than 200 species of avian Haemosporidia (genera Plasmodium, Haemoproteus, and Leucocytozoon) have been described based primarily on morphological characters seen in blood smears. Recent molecular studies, however, suggest that such methods may mask a substantial cryptic diversity of avian haemosporidians. We surveyed the haemosporidians of birds sampled at 1 site in Israel. Parasites were identified to species based on morphology, and a segment of the parasite's cytochrome b gene was sequenced. We compared 3 species concepts : morphological, genetic, and phylogenetic. Fifteen morphological species were present. Morphological species that occurred once within our dataset were associated with a unique gene sequence, displayed large genetic divergence from other morphological species, and were not contained within clades of morphological species that occurred more than once. With only 1 exception, morphological species that were identified from multiple bird hosts presented identical sequences for all infections, or differed by few synonymous substitutions, and were monophyletic for all phylogenetic analyses. Only the morphological species Haemoproteus belopolskyi did not follow this trend, falling instead into at least 2 genetically distant clades. Thus, except for H. belopolskyi, parasites identified to species by morphology were supported by both the genetic and phylogenetic species concepts.

No abstract

Two new genera are proposed to accomodate new and previously described species of eimerian coccidia from reptiles which undergo endogenous development either in the bile epithelium-Choleoeimeria n. gen., or in the microvillous zone of the intestinal epithelium-Acroeimeria n. gen. Endogenous development is described from 3 species, all from geckoes: C. turcicus (syn. Eimeria turcicus Upton, McAllister and Freed, 1988) from Hemidactylus turcicus in Israel; C. pachydactyli n. sp. from Pachydactylus capensis in South Africa and A. lineri (syn. Eimeria /ineri McAllister, Upton and Freed, 1988) from H. turcicus, Israel and H. mabouia, South Africa. Biliary epithelial cells infected by Choleoeimeria become hypertrophic and are displaced to the surface of the epithelial layer. Oocysts are cylindroid to oval, lack a stieda body and sporulate in the gall bladder. The developing endogenous stages of Acroeimeria, enclosed in the microvillous border of the host cell, expand into the intestinal lumen. Oocysts are oval-spherical, lack a stieda body and sporulation is exogenous.

An integrated biological effect monitoring concept has been tested in flounder (Platichthys flesus L.) from four locations with different anthropogenic impact in the German Bight. During 3 years of sampling, biomarkers at all levels of biological organisation from the molecular to the ecosystem level were applied and tested on 742 individual fish of body lengths between 18 and 25 cm. At the ecosystem level, the fish were taken as a habitat for the parasite assemblage. The hypothesis was that changes in the environment might lead to changes in the species diversity of parasites and in the infection intensity of single species, as well as between heteroxenic and monoxenic parasite species (H/M ratio). At the molecular level, activity of the CYP1A-dependent monooxygenase ethoxyresorufin O-deethylase (EROD) was used as a biomarker of exposure. At the subcellular level, the integrity of lysosomal membranes in hepatocytes was taken as an indicator of non-specific acute and chronic toxic effects. Both biomarkers are recommended by the ICES Advisory Committee on the Marine Environment for the application in biological effects monitoring programmes. In addition, neutral lipid content in the liver was used as a marker for pathologically induced fat accumulation. In the same individual fish, a new method for the measurement of macrophage aggregate activity in the liver was tested for its application and reliability in reflecting immunosuppression. Tests were accompanied by chemical analysis of standard organochlorine and heavy metal residues in flounder tissue. A total of 33 parasite species were found. As an indicator species, the mean abundance of Trichodina sp. reflected best the pollution gradient observed with highest infection intensity at the most polluted location. Species diversity was significantly higher in fish caught near the reference site and significantly lower in fish from the polluted Elbe estuary. The use of the heteroxenous/monoxenous species ratio as a marker was not useful at the locations investigated because of the dominance of heteroxenous species at all habitats. Since EROD activity and macrophage aggregate activity were dependent on sex and maturity of female flounder, only male fish were taken into consideration for the integrated evaluation of data. All biochemical and histochemical tests were able to reflect accurately the site-specific differences, as well as an observed pollution event at the end of 1995 as determined by chemical analyses. The correlation analysis revealed a connection not only between the single parasitological and biochemical parameters but also within these groups. The non-specific immune response and Trichodina infection intensity were correlated with all other parameters, leading to the assumption that these may serve as links between the lowest and the highest levels of biological organisation. The simultaneous use of metabolic and parasitological results facilitated the interpretation of the observed variations of the data and the distinction between natural ...

Among hatchery bred Sparus aurata, 5.4% of the offspring of a single parent pair showed severe skeletal deformations coupled with marked growth retardation and pathological changes in the swimbladder. This resulted from extreme proliferation, then hypertrophy, of the cuboidal epithelial cells of the gas gland and proliferation of the rete mirabile. This caused almost complete congestion of the swimbladder air space. The nature of the pathological changes in the swimbladder and the possibility of hereditary origin for both the skeletal and swimbladder deformations are discussed.

No abstract

Gilt-head sea bream, Sparus aurata L., the Mediterranean's most important mariculture species, has been cultured for the last 30 yr in Eilat (Israeli Red Sea). Kudoa sp. was the first myxosporean parasite reported from this species. In recent years, an increase in prevalence in both land-based and sea-cage facilities in Eilat has been observed. Infections with the same Kudoa species appeared in cultured European sea bass Dicentrarchus labrax (L.) and grey mullet Mugil cephalus in the same farms, as well as in 10 species of wild Red Sea reef fish, indicating that Kudoa sp. is not fastidious with regard to its host. All affected species displayed 1- to 2-mm (up to 5 mm) whitish, spherical, or oval polysporous plasmodia. The parasite established multiple site infections, most commonly in the muscles and intracranial adipose tissue of the brain and eye periphery. Other sites were subcutaneous adipose tissue, nerve axons, mouth, eye, mesenteries, peritoneum, swim bladder, intestinal musculature, heart, pericardium, kidney, and ovary. On the basis of spore morphology, the parasite was identified as Kudoa iwatai Egusa and Shiomitsu, 1983. Ultrastructural features were comparable to those of previously studied Kudoa species. The 18S rDNA from 7 Red Sea isolates was sequenced and compared with the sequence of the same gene from K. iwatai isolated from cultured red sea bream, Pagrus major, in Japan. The phylogenetic position of K. iwatai within the genus was determined using sequence analysis of all related taxa available in GenBank. The 3 isolates of K. iwatai clustered together on a newly formed, highly supported clade. The Red Sea strain of K. iwatai is apparently native to the region. In the absence of records of this Kudoa sp. from the extensive Mediterranean sea bream and sea bass production industries, introduction with its Mediterranean hosts seems unlikely. Therefore, we conclude that K. iwatai is an Indo-Pacific species that, in the Red Sea, has extended its host range to include the allochthonous gilt-head sea bream, European sea bass, and grey mullet.