Tetra disseminated microsporidiosis: a novel disease in ornamental fish caused by Fusasporis stethaprioni n. gen. n. sp.

A novel microsporidial disease was documented in two ornamental fish species, black tetra Gymnocorymbus ternetzi Boulenger 1895 and cardinal tetra Paracheirodon axelrodi Schultz 1956. The non-xenoma-forming microsporidium occurred diffusely in most internal organs and the gill, thus referring to the condition as tetra disseminated microsporidiosis (TDM). The occurrence of TDM in black tetra was associated with chronic mortality in a domestic farmed population, while the case in cardinal tetra occurred in moribund fish while in quarantine at a public aquarium. Histology showed that coelomic visceral organs were frequently necrotic and severely disrupted by extensive infiltrates of macrophages. Infected macrophages were presumed responsible for the dissemination of spores throughout the body. Ultrastructural characteristics of the parasite developmental cycle included uninucleate meronts directly in the host cell cytoplasm. Sporonts were bi-nucleated as a result of karyokinesis and a parasite-produced sporophorous vesicle (SPV) became apparent at this stage. Cytokinesis resulted in two spores forming within each SPV. Spores were uniform in size, measuring about 3.9 ± 0.33 long by 2.0 ± 0.2 µm wide. Ultrastructure demonstrated two spore types, one with 9-12 polar filament coils and a double-layered exospore and a second type with 4-7 polar filament coils and a homogenously electron-dense exospore, with differences perhaps related to parasite transmission mechanisms. The 16S rDNA sequences showed closest identity to the genus Glugea (≈ 92%), though the developmental cycle, specifically being a non-xenoma-forming species and having two spores forming within a SPV, did not fit within the genus. Based on combined phylogenetic and ultrastructural characteristics, a new genus (Fusasporis) is proposed, with F. stethaprioni n. gen. n. sp. as the type species.

The development of manual midline crossing in 2- to 6-year-old children.

The present study analyzed the development of manual midline crossing in a sample of one hundred sixty 2- to 6-year-old children and considered test construction factors that could affect the test design. The test construction factors addressed were (a) the effect of biasing the hand used for object manipulation and (b) the effect of distance from midline required for task completion on the frequency of manual midline crossing. A pegboard task was used to measure manual midline crossing. The results identified a developmental age trend in crossing the body midline in 2- to 6-year-old children. Biasing the hand used for object manipulation significantly increased the probability of eliciting manual midline crossing. A combination of linear and quadratic trends was found when the effect of distance from midline on the frequency of contralateral responses produced during testing was analyzed.

Relationship between development of the body-righting reaction and manual midline crossing behavior in the learning disabled.

The study was designed to consider the possible relationship between the development and integration of the body-righting reaction and the development of manual midline crossing behavior in learning-disabled and normal children aged 6 to 8 years (23 subjects in each group). A combination of three movement patterns (rolling from supine to prone, transition from supine to standing, and equilibrium in sitting) was used to analyze the body-righting reaction. The Space Visualization Contralateral Use (SVCU) score derived from the Southern California Space Visualization Test was used to measure manual midline crossing behavior. Results of the study found that the learning-disabled subjects exhibited significantly reduced performance on both test measures, when compared to the normal controls. A correlation between scores on the two tests did not reach significance. The findings are described as they relate to sensory integration testing, and the need for further study of the body-righting reaction and manual midline crossing behavior.

Postrotatory nystagmus duration as a function of communication disorders.

The purpose of this study was to explore the relationship between functioning of the vestibular system, measured by duration of postrotatory mystagmus, and specific communiccation disorders (articulation, speech and language, and language). A total of 190 children participated in the study, 173 of which were included in the final data analysis. The findings revealed a depressed mean duration of postrotatory nystagmus in all categories of communication disorders when compared to the control group. In addition, the language group had a sig;ificantly lower mean duration of postrotatory nystagmus when compared to the articulation and speech and language groups. Although the test measure did discriminate between groups, it did not discriminate well between children within groups.