Advancing Prenatal Detection of Congenital Heart Disease: A Novel Screening Protocol Improves Early Diagnosis of Complex Congenital Heart Disease.

OBJECTIVES: Prenatal diagnosis of complex congenital heart disease (CHD) during routine obstetric ultrasound (US) examinations improves postnatal outcomes, but sensitivity is low (<40%). Our objective was to improve our prenatal detection of complex CHD with implementation of a specific screening protocol. METHODS: From January 2003 to December 2013, 506 consecutive confirmed cases of complex CHD in the province of Manitoba, Canada, were analyzed to compare the sensitivity and positive predictive value of prenatal US detection of complex CHD before and after the introduction of a novel prenatal screening protocol. The intervention was done in October 2004, emphasizing screening and not diagnosis of complex CHD. It involved education, practical scanning tips, a checklist, and feedback on cases. We also assessed the effect of the intervention in different screening settings: community hospitals, tertiary hospitals, and fetal assessment units. RESULTS: The sensitivity for detecting complex CHD increased from 29.8% to 88.3% (P < .0001), while the positive predictive value remained high. The largest improvement in detection was found for US units in community hospitals (52.4% higher; P < .0001), followed by tertiary hospitals (39.9%; P = .0004), and fetal assessment units (7.2%; P = .16). Additionally, there was a significant decrease in the presentation of neonates in critical condition from before to after the implementation (24.3% to 13.1%, respectively; P = .0165). CONCLUSIONS: Implementing a focused routine prenatal screening protocol can vastly improve detection rates of critical cardiac abnormalities. The improvement in community hospitals was particularly important because early detection ensured that the birth was planned to take place in an appropriate facility. Our novel protocol can be performed by all sonographers, regardless of experience, equipment used, and hospital setting.

A new species of treefrog (Litoria) from Cape York Peninsula, Australia.

We describe a new species of treefrog from northern Australia. Litoria bella sp. nov. is morphologically and genetically most similar to frogs in the L. gracilenta and L. chloris groups but is distinguished from all members in these groups by a combination of a moderately large male body size (34.5-41.8 mm SVL), near-immaculate green dorsum, orange venter, bright orange digits and webbing, bluish purple lateral surfaces of the thighs, no pale canthal stripe, white bones, and a highly-pulsed, single-note, male advertisement call with a pulse rate of 56-64 pulses/s and dominant frequency of 2.6-2.8 kHz. Litoria bella sp. nov. has a patchy distribution across the Cape York Peninsula, inhabiting rainforest and monsoon vine thicket in close association with watercourses. The new species' affinities lie with L. auae from southern New Guinea rather than with L. gracilenta from eastern Australia. Molecular data suggest that the L. gracilenta group should be expanded to include L. chloris and L. xanthomera, two moderately large green treefrogs from eastern Australia.

An Ancient Divide in a Contiguous Rainforest: Endemic Earthworms in the Australian Wet Tropics.

Understanding the factors that shape current species diversity is a fundamental aim of ecology and evolutionary biology. The Australian Wet Tropics (AWT) are a system in which much is known about how the rainforests and the rainforest-dependent organisms reacted to late Pleistocene climate changes, but less is known about how events deeper in time shaped speciation and extinction in this highly endemic biota. We estimate the phylogeny of a species-rich endemic genus of earthworms (Terrisswalkerius) from the region. Using DEC and DIVA historical biogeography methods we find a strong signal of vicariance among known biogeographical sub-regions across the whole phylogeny, congruent with the phylogeography of less diverse vertebrate groups. Absolute dating estimates, in conjunction with relative ages of major biogeographic disjunctions across Australia, indicate that diversification in Terrisswalkerius dates back before the mid-Miocene shift towards aridification, into the Paleogene era of isolation of mesothermal Gondwanan Australia. For the Queensland endemic Terrisswalkerius earthworms, the AWT have acted as both a museum of biological diversity and as the setting for continuing geographically structured diversification. These results suggest that past events affecting organismal diversification can be concordant across phylogeographic to phylogenetic levels and emphasize the value of multi-scale analysis, from intra- to interspecies, for understanding the broad-scale processes that have shaped geographic diversity.

Chytridiomycosis and seasonal mortality of tropical stream-associated frogs 15 years after introduction of Batrachochytrium dendrobatidis.

Assessing the effects of diseases on wildlife populations can be difficult in the absence of observed mortalities, but it is crucial for threat assessment and conservation. We performed an intensive capture-mark-recapture study across seasons and years to investigate the effect of chytridiomycosis on demographics in 2 populations of the threatened common mist frog (Litoria rheocola) in the lowland wet tropics of Queensland, Australia. Infection prevalence was the best predictor for apparent survival probability in adult males and varied widely with season (0-65%). Infection prevalence was highest in winter months when monthly survival probabilities were low (approximately 70%). Populations at both sites exhibited very low annual survival probabilities (12-15%) but high recruitment (71-91%), which resulted in population growth rates that fluctuated seasonally. Our results suggest that even in the absence of observed mortalities and continued declines, and despite host-pathogen co-existence for multiple host generations over almost 2 decades, chytridiomycosis continues to have substantial seasonally fluctuating population-level effects on amphibian survival, which necessitates increased recruitment for population persistence. Similarly infected populations may thus be under continued threat from chytridiomycosis which may render them vulnerable to other threatening processes, particularly those affecting recruitment success.

Application of the survey protocol for chytridiomycosis to Queensland, Australia.

Spread of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, has resulted in the extinction of frogs, but the distribution of Bd is incompletely known. We trialled the survey protocol for Bd by attempting to systematically map its distribution in Queensland, Australia. Bd was easily detected in known infected areas, such as the Wet Tropics and South East Queensland. It was not detected in bioregions adjacent to, but inland from or to the north of, infected regions: Einasleigh Uplands and Cape York adjacent to the infected Wet Tropics; and Brigalow Belt South adjacent to the infected South East Queensland bioregion. These regions where Bd was not detected have bordered infected regions for between 15 yr (in northern Queensland) and 30 yr (in southern Queensland), and so they define the geographical limits of Bd with regard to the long-term environmental conditions in Queensland. The Gulf Plains, a bioregion distant from infected bioregions, was also negative. Bd was confined to rainforest and bordering habitats, such as wet eucalypt forests. Infections were largely confined to permanent water-associated species, consistent with this being an important cause of this group having the greatest declines. Our data supports biogeographic climatic models that show much of inland and northern Australia to be too hot and dry to support Bd. As there is limited opportunity for Bd to spread further in Queensland, the priority for management is reducing the impact of Bd in affected populations and assisting frogs to disperse into their former distributions. Given that the survey protocol has been applied successfully in Australia it may be useful for mapping the distribution of Bd in other parts of the world.

Survey protocol for detecting chytridiomycosis in all Australian frog populations.

Spread of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused the decline and extinction of frogs, but the distribution of Bd is not completely known. This information is crucial to implementing appropriate quarantine strategies, preparing for outbreaks of chytridiomycosis due to introduction of Bd, and for directing conservation actions towards affected species. This survey protocol provides a simple and standard method for sampling all frog populations in Australia to maximise the chances of detecting Bd. In order to structure and prioritise the protocol, areas are divided by bioregion and frog species are allocated depending on the water bodies they utilize into 3 groups representing different levels of risk of exposure to Bd. Sixty individuals per population need to be tested to achieve 95% certainty of detecting 1 positive frog, based on the minimum apparent prevalence of > or =5% in infected Australian frog populations and using a quantitative real-time TaqMan PCR test. The appropriate season to sample varies among bioregions and will ideally incorporate temperatures favourable for chytridiomycosis (e.g. maximum air temperatures generally <27 degrees C). Opportunistic collection and testing of sick frogs and tadpoles with abnormal mouth-parts should also be done to increase the probability of detecting Bd. The survey priorities in order are (1) threatened species that may have been exposed to Bd, (2) bioregions surrounding infected bioregions/ecological groups, and (3) species of frogs of unknown infection status in infected bioregions. Within these priority groups, sampling should first target ecological groups and species likely to be exposed to Bd, such as those associated with permanent water, and areas within bioregions that have high risk for Bd as indicated by climatic modelling. This protocol can be adapted for use in other countries and a standard protocol will enable comparison among amphibian populations globally.

Reinforcement drives rapid allopatric speciation.

Allopatric speciation results from geographic isolation between populations. In the absence of gene flow, reproductive isolation arises gradually and incidentally as a result of mutation, genetic drift and the indirect effects of natural selection driving local adaptation. In contrast, speciation by reinforcement is driven directly by natural selection against maladaptive hybridization. This gives individuals that choose the traits of their own lineage greater fitness, potentially leading to rapid speciation between the lineages. Reinforcing natural selection on a population of one of the lineages in a mosaic contact zone could also result in divergence of the population from the allopatric range of its own lineage outside the zone. Here we test this with molecular data, experimental crosses, field measurements and mate choice experiments in a mosaic contact zone between two lineages of a rainforest frog. We show that reinforcing natural selection has resulted in significant premating isolation of a population in the contact zone not only from the other lineage but also, incidentally, from the closely related main range of its own lineage. Thus we show the potential for reinforcement to drive rapid allopatric speciation.