Unusual tumour-like pathologies caused by mysterious cells termed 'X-cells' have been reported from numerous fish groups worldwide. After nearly 100 years of research, the tumour-like growths have recently been shown to be caused by a protozoan parasite. In the present study, histopathology and small subunit ribosomal DNA (SSU rDNA) sequences are used to assess whether the X-cell parasite infecting Atlantic dab Limanda limanda L. is distinct from the X-cell parasite infecting Japanese flounder and goby, and to determine their systematic position within the protists. SSU rDNA from Scottish dab was 89.3% and 86.7% similar to Japanese X-cell sequences from flounder and goby respectively, indicating that the parasite infecting dab in the Atlantic is distinct from the Pacific species. Histological studies revealed significant gill pathology and demonstrated the precise location of the parasites within the gill tissues using specific in situ hybridization probes. Phylogenetic analyses showed that the X-cell parasites from Scotland and Japan form a monophyletic group within the Myzozoa, and are basal alveolates. However, ultrastructure of X-cells from dab fails to confirm this systematic placement.
Cage-cultured Asian redtail catfish Hemibagrus nemurus (Valenciennes, 1840), a popular food fish in Southeast Asia, proved to be infected by 3 myxozoan species. All the 3 species belonged to the genus Henneguya: 2 were identified as H. mystusia Sarkar, 1985 and H. hemibagri Tchang et Ma, 1993, while the other was described as H. basifilamentalis sp. n. All plasmodia were found in the gills and were characterised by a specific site selection. H. mystusia formed plasmodia in the multi-layered epithelium between the gill lamellae and in the non-lamellar edge of the gill filaments, while H. hemibagri developed in the capillary network of the lamellae. H. basifilamentalis sp. n. had large oval plasmodia located deep among the filaments just above the gill arch.
Any forms of valorization of microorganisms would require accurate identity recognition to ensure repeatability, reproducibility and quality assurance. This study aimed to evaluate the effectiveness of different primers for identifying cultured eukaryotic microalgae using a simple 18S rDNA approach. A total of 34 isolated microalgae and one culture collection were utilized in the search for an effective molecular identification method for microalgae. Ammonium formate was applied to marine microalgae prior to DNA extraction. The microalgal DNA was extracted using a commercial kit and subjected directly to PCR amplification using four different published 18S rDNA primers. The DNA sequences were analysed using Basic Local Alignment Search Tool (BLAST) and phylogenetic trees to determine the microalgae identity. The identity was further validated with conventional morphological taxonomic identification, and the relationship of microalgal morphology and genetic materials was also determined. The microalgal DNA was successfully amplified, including marine species without prior cleaning. In addition, the ss5 + ss3 primer pair was found to be an ideal primer set among the tested primers for identifying microalgae. Overall, molecular identification showed relative matching with morphological identification (82.86%). This study is important because it serves as a platform to develop a standardized eukaryotic microalgae identification method. In addition, this method could help to ease the eukaryotic microalgae identification process and enrich the current reference databases such as GenBank.
Parasites and bacteria are reported in the faeces of birds in the current study. Fresh faecal samples of the large-billed crow (Corvus spp.) were collected from the study site at Bangsar, an urban setting in Kuala Lumpur, Malaysia. These samples were transported to laboratory and analysed for parasites and bacteria. Pre-prepared XLD agar plates were used for culturing the bacteria in the laboratory. Using the API 20ETM Test Strips, 9 different species of bacteria were identified belonging to the family Enterobacteriacea. They were Citrobacter freundii, Enterobacter cloacae, Proteus mirabilis, Klebsiella pneumoniae, Kluyvera ascorbata, Salmonella arizonae, Salmonella typhi, Shigella flexneri and Shigella sonnei. The protozoan parasites detected include Cryptosporidium spp., Cyclospora spp., Blastocystis spp., and Capillaria hepatica and Ascaris lumbricoidus ova. Environmental air samples collected on agar plates using an air sampler in the area only produced fungal colonies. Some of these pathogens found in the crows are of zoonotic importance, especially Cryptosporidium, Blastocystis, Cyclopsora, Salmonella, Shigella and Kluyvera. The finding of Kluyvera spp. in crows in our current study highlights its zoonotic potential in an urban setting.
Cage-cultured sutchi catfish Pangasius hypophthalmus (Sauvage, 1878), a favourite food fish in Southeast Asia, proved to be infected by 6 myxozoan species. Three species belonged to the genus Hennegoides (H. berlandi, H. malayensis, and H. pangasii), 1 to Henneguya (H. shariffi) and 2 to Myxobolus (M. baskai, and M. pangasii). Five myxozoans infected the gills and 1 was found on the spleen. Myxozoans infecting the gills were characterised by a specific site selection. H. shariffi sp. n. and H. berlandi sp. n. formed plasmodia in the multi-layered epithelium of the gill filaments. Of the 2 vascular species H. pangasii sp. n. developed in the gill arteries, while M. baskai sp. n. infected the capillary network of the gill lamellae. Plasmodia of H. malayensis sp. n. were found inside the cartilaginous gill rays of the filaments. Large plasmodia of M. pangasii sp. n. were located in a groove of the spleen but they affected only the serosa layer covering the spleen.
The objective was to estimate the prevalence of intestinal protozoa among the aborigines and to determine the problems regarding the infection. The study was carried out in January 2006 in Pos Senderut, Pahang, Malaysia. Samples of faeces were collected from children and adults and these were fixed in PVA and trichrome staining was carried out. From the 130 individuals studied, 94 (72.3%) were positive with at least one intestinal protozoa. Nine intestinal protozoa namely Blastocystis hominis, Giardia lamblia, Entamoeba histolytica, Entamoeba coli, Endolimax nana, Entamoeba hartmani, Entamoeba polecki, Iodamoeba butschlii and Chilomastix mesnili were detected. The prevalent species were B. hominis (52.3%), followed by G. lamblia (29.2%), E. coli (26.2%) and E. histolytica (18.5%). The other species ranged from 1.5 to 10.8%. Among the positive samples, mixed infection with E. histolytica and G. lamblia was 3.8%, E. histolytica and B. hominis was 15.4%, G. lamblia and B. hominis was 17.7%. Triple infection of E. histolytica, G. lamblia and B. hominis was 3.1%. The infection was more prevalent in children below 10 years age group (45.4%) and lowest in the age above 60 years (3.8%). The high prevalence was attributable to poor environmental management, poor personal hygiene and lack of health education.
Sarcocystis booliati n.sp. is described from the moonrat Echinosorex gymnurus (Mammalia, Insectivora) from West Malaysia. The cysts are very thin-walled, not visible to the naked eye, and have no trabeculae or cytophaneres. They are found in skeletal but not heart muscle. The zoites are small, 5-8 by 2-3 mum with a mean of 6.5 by 2.2 mum, in dry fixed smears. Octoplasma garnhami n.gen. n.sp., a parasite of undetermined taxonomic status but belonging to the Coccidiasina, Apicomplexa, is also described from the same host. Only schizononts and pseudocysts with typically 8 zoites, have so far been seen in monocytes of the spleen and liver. The zoites are large, 15 by 3 mum and have a distinct nucleolus even in dry-fixed smears.