Identification of novel Babesia and Theileria genotypes in the endangered marsupials, the woylie (Bettongia penicillata ogilbyi) and boodie (Bettongia lesueur)

Piroplasms, which include the genera Theileria and Babesia, are blood-borne parasites transmitted mainly by tick vectors. Relatively little is known about their prevalence and clinical impact in Australian marsupials. In the present study the occurrence and molecular phylogeny of these parasites were studied in both wild and captive marsupials from Western Australia (WA) and Queensland (QLD). Blood samples were screened by microscopy and molecular methods, using PCR and DNA sequencing of the 18S ribosomal RNA gene (18S rDNA). Overall, 7.1% of the blood samples (8/113) were positive for piroplasm 18S rDNA. Theileria and Babesia rDNA was detected in 0.9% (1/113) and 6.2% (7/113) of the animals, respectively. The single Theileria positive was identified in one of three boodies (Bettongia lesueur) screened from a wildlife rehabilitation centre in WA, while all seven Babesia positives were detected in WA in wild captured woylies (Bettongia penicillata ogilbyi). Small intraerythrocytic inclusions were observed in blood films made from six of these individuals. This is the first report of a Babesia sp. in woylies, and Theileria sp. in boodies. Phylogenetic analysis indicated that the woylie-derived Babesia was genetically distinct and most closely related to Babesia occultans, the causative agent of a benign form of cattle babesiosis (genetic similarity 98.4%). The Theileria identified was most closely related to the marsupial-derived species Theileria penicillata from the woylie, Theileria brachyuri from the quokka (Setonix brachyurus), and Theileria sp. from the long-nosed potoroo (Potorous tridactylus).     

CD46 (membrane cofactor protein) acts as a human epithelial cell receptor for internalization of opsonized uropathogenic Escherichia coli

Escherichia coli is a common urinary pathogen whose uptake into epithelial cells is mediated by attachment through type 1 fimbriae. In this study, we show by using using human urinary tract epithelial cells that maximal internalization of E. coli is achieved only when bacteria are opsonized with complement. The concentrations of complement proteins in the urine rise sufficiently during infection to allow bacterial opsonization. The complement regulatory protein, CD46 (membrane cofactor protein), acts in cohort with fimbrial adhesion to promote the uptake of pathogenic E. coli. This uptake is inhibited by RNA interference to lower the expression of CD46 and by soluble CD46 that will competitively inhibit opsonized bacteria binding to cell surface CD46. We propose that efficient internalization of uropathogenic E. coli by the human urinary tract depends on cooperation between fimbrial-mediated adhesion and C3 receptor (CD46)-ligand interaction. Complement receptor-ligand interaction could pose a new target for interrupting the cycle of reinfection due to intracellular bacteria.     

Developmental response to cold stress in cranial morphology of Rattus: implications for the interpretation of climatic adaptation in fossil hominins

Adaptation to climate occupies a central position in biological anthropology. The demonstrable relationship between temperature and morphology in extant primates (including humans) forms the basis of the interpretation of the Pleistocene hominin Homo neanderthalensis as a cold-adapted species. There are contradictory signals, however, in the pattern of primate craniofacial changes associated with climatic conditions. To determine the direction and extent of craniofacial change associated with temperature, and to understand the proximate mechanisms underlying cold adaptations in vertebrates in general, dry crania from previous experiments on cold- and warm-reared rats were investigated using computed tomography scanning and three-dimensional digitization of cranial landmarks. Aspects of internal and external cranial morphology were compared using standard statistical and geometric morphometric techniques. The results suggest that the developmental response to cold stress produces subtle but significant changes in facial shape, and a relative decrease in the volume of the maxillary sinuses (and nasal cavity), both of which are independent of the size of the skull or postcranium. These changes are consistent with comparative studies of temperate climate primates, but contradict previous interpretations of cranial morphology of Pleistocene Hominini.     

Longitudinal multi-locus molecular characterisation of sporadic Australian human clinical cases of cryptosporidiosis from 2005 to 2008

Cryptosporidium is a gastrointestinal parasite that is recognised as a significant cause of non-viral diarrhea in both developing and industrialised countries. In the present study, a longitudinal analysis of 248 faecal specimens from Australian humans with gastrointestinal symptoms from 2005 to 2008 was conducted. Sequence analysis of the 18S rRNA gene locus and the 60 kDa glycoprotein (gp60) gene locus revealed that 195 (78.6%) of the cases were due to infection with Cryptosporidium hominis, 49 (19.8%) with Cryptosporidium parvum and four (1.6%) with Cryptosporidium meleagridis. A total of eight gp60 subtype families were identified; five C. hominis subtype families (Ib, Id, Ie, If and Ig), and two C. parvum subtype families (IIa and IId). The Id subtype family was the most common C. hominis subtype family identified in 45.7% of isolates, followed by the Ig subtype family (30.3%) and the Ib subtype family (20%). The most common C. parvum subtype was IIaA18G3R1, identified in 65.3% of isolates. The more rare zoonotic IId A15G1 subtype was identified in one isolate. Statistical analysis showed that the Id subtype was associated with abdominal pain (p < 0.05) and that in sporadic cryptosporidiosis, children aged 5 and below were 1.91 times and 1.88 times more likely to be infected with subtype Id (RR 1.91; 95% CI, 1.7-2.89; p < 0.05) and Ig (RR 1.88; 95% CI, 1.10-3.24; p < 0.05) compared to children aged 5 and above. A subset of isolates were also analysed at the variable CP47 and MSC6-7 gene loci. Findings from this study suggest that anthroponotic transmission of Cryptosporidium plays a major role in the epidemiology of cryptosporidiosis in Western Australian humans.     

Identification of rare and novel Cryptosporidium GP60 subtypes in human isolates from Jordan

Little is known about the epidemiology of Cryptosporidium in Jordan and no genotyping studies have been conducted on Cryptosporidium isolates from humans or animals from Jordan. Genotyping of 44 Cryptosporidium isolates from Jordanian children at the 18S rRNA locus and a unique diagnostic locus identified four Cryptosporidium species; C. parvum (22), C. hominis (20), C. meleagridis (1) and C. canis (1). Sub-genotype analysis of 29 isolates at the 60-kDa glycoprotein (GP60) locus identified three C. parvum, two C. hominis subtype families and one C. meleagridis subtype. Several rare and novel subtypes were identified indicating unique endemicity and transmission of Cryptosporidium in Jordan.     

An Australian network to support the understanding and control of parasites

The Australian Research Council (ARC) and the National Health and Medical Research Council (NHMRC) Research Network for Parasitology will focus and coordinate the fundamental, strategic and applied parasitology research in Australia. It will raise the standing of Australia in the field, assist in the community understanding of parasitology, and maintain and improve the capacity of Australia to keep its stock, crops, wildlife and people free from disease. On an international scale, the ARC/NHMRC Network will work with other countries to develop new technologies for the detection and control of parasites.     

Contribution of renal secreted complement C3 to the circulating pool in humans

Complement C3 produced within the kidney may be an important mediator of local inflammatory and immunological injury. The overall level of renal C3 production and consequently its contribution to the total circulating C3 level are, however, unknown. This was investigated by using the conversion of C3 from recipient to donor allotype following renal transplantation. The C3 F and S allotypes of 80 consecutive renal donor-recipient pairs (148 individuals) were determined by amplification refractory mutation system analysis. The extent of allotype conversion in C3 F/S mismatched recipients was quantified at different stages after transplantation, using an enzyme-linked immunosorbent assay specific for the HAV 4-1 polymorphism of C3 that is strongly associated with C3F. Twenty-one of the eighty recipients were potentially informative, i.e., were C3 SS recipients of C3 FF or FS donor kidneys. In the early postoperative period, donor-derived C3 (HAV 4-1-positive) was undetectable, increasing to 9.6% of the total circulating C3 at times of acute allograft rejection. When graft dysfunction occurred from causes other than rejection, donor C3 remained undetectable. After stable graft function was attained (3-13 mo after transplantation), donor C3 made up 4.5% of the total circulating C3 pool. Our findings demonstrate that human transplant kidney in the resting state is a significant source of extrahepatic C3. Its heightened local synthesis during rejection episodes suggests a possible pathogenic role for C3 in this immunological process.     

Recent evolutionary history of human immunodeficiency virus type 1 subtype B--response

The year of origin estimated by Lukashov and Goudsmit for HIV-1 subtype B is 1976 (95% CI, 1974-1977); this is significantly different from our prior estimate, 1967 (95% CI, 1960-1971). We review published evidence, which suggests that their estimate is too late.