The evolution of multiple colour mechanisms is correlated with diversification in sunbirds (Nectariniidae).

How and why certain groups become speciose is a key question in evolutionary biology. Novel traits that enable diversification by opening new ecological niches are likely important mechanisms. However, ornamental traits can also promote diversification by opening up novel sensory niches and thereby creating novel inter-specific interactions. More specifically, ornamental colours may enable more precise and/or easier species recognition, and may act as key innovations by increasing the number of species-specific patterns and promoting diversification. While the influence of colouration on diversification is well-studied, the influence of the mechanisms that produce those colours (e.g. pigmentary, nanostructural) is less so, even though the ontogeny and evolution of these mechanisms differ. We estimated a new phylogenetic tree for 121 sunbird species and combined colour data of 106 species with a range of phylogenetic tools to test the hypothesis that the evolution of novel colour mechanisms increases diversification in sunbirds, one of the most colourful bird clades. Results suggest that (1) the evolution of novel colour mechanisms expands the visual sensory niche, increasing the number of achievable colours. (2) Structural colouration diverges more readily across the body than pigment-based colouration, enabling an increase in colour complexity. (3) Novel colour mechanisms might minimize trade-offs between natural and sexual selection such that colour can function both as camouflage and conspicuous signal. (4) Despite structural colours being more colourful and mobile, only melanin-based colouration is positively correlated with net diversification. Together, these findings explain why colour distances increase with increasing number of sympatric species, even though packing of colour space would predict otherwise.

Toxic shock syndrome surveillance in UK children.

BACKGROUND: Toxic shock syndrome (TSS) is an acute toxin-mediated illness caused by toxin-producing strains of Staphylococcus aureus and Streptococcus pyogenes. There is no recent data regarding incidence, management and mortality of TSS in UK children. METHODS: Consultants from paediatric and burns units in the UK and Ireland, reported cases of TSS seen between November 2008 and December 2009, via the British Paediatric Surveillance Unit. Respondents were sent questionnaires requesting detailed information about TSS cases. Established criteria were used to divide cases into staphylococcal or streptococcal TSS. RESULTS: Forty-nine cases were identified overall; 29 cases of streptococcal TSS (18 confirmed and 11 probable) and 20 cases of staphylococcal TSS (15 confirmed and 5 probable). The incidence of TSS children in the UK & the Republic of Ireland was calculated to be 0.38 per 100 000 children. Children with staphylococcal TSS were older than those with streptococcal TSS (9.5 vs 3.8 years; p<0.003). Paediatric intensive care facilities were used for 78% of cases (invasive ventilatory support 69%; inotropic support 67%; haemofiltration 12%). Agents with antitoxin effects were underused; clindamycin 67%, intravenous immunoglobulin (IVIG) 20%, fresh frozen plasma 40%. There were eight deaths, all in the streptococcal group (28% of streptococcal cases)-none were given IVIG. CONCLUSIONS: Streptococcal TSS was as frequent as staphylococcal TSS, contrasting with previous literature. Children with streptococcal TSS had a higher mortality than those with staphylococcal TSS (28% vs 0%; p<0.05). Recommended immunomodulatory agents (IVIG and clindamycin) were underused. This study highlights the need for a guideline to improve management of TSS in children.

Diversification and the adaptive radiation of the vangas of Madagascar.

The vangas of Madagascar exhibit extreme diversity in morphology and ecology. Recent studies have shown that several other Malagasy species also are part of this endemic radiation, even as the monophyly of the clade remains in question. Using DNA sequences from 13 genes and representatives of all 15 vanga genera, we find strong support for the monophyly of the Malagasy vangids and their inclusion in a family along with six aberrant genera of shrike-like corvoids distributed in Asia and Africa. Biogeographic reconstructions of these lineages include both Asia and Africa as possible dispersal routes to Madagascar. To study patterns of speciation through time, we introduce a method that can accommodate phylogenetically non-random patterns of incomplete taxon sampling in diversification studies. We demonstrate that speciation rates in vangas decreased dramatically through time following the colonization of Madagascar. Foraging strategies of these birds show remarkable congruence with phylogenetic relationships, indicating that adaptations to feeding specializations played a role in the diversification of these birds. Vangas fit the model of an 'adaptive radiation' in that they show an explosive burst of speciation soon after colonization, increased diversification into novel niches and extraordinary ecomorphological diversity.

Improved case confirmation in meningococcal disease with whole blood Taqman PCR.

BACKGROUND: The clinical diagnosis of meningococcal disease (MCD) can be difficult. Non-culture methods like the previous ELISA meningococcal PCR improved case confirmation rates, but were not ideal. A Taqman meningococcal PCR, using DNA extracted from serum (S-Taqman), which has an improved sensitivity compared to the ELISA method in vitro, was introduced into clinical practice in July 1997. A new whole blood DNA extraction method for Taqman (WB-Taqman) was introduced in September 1999. AIMS: To determine the degree of improvement in the confirmation rate in clinically diagnosed MCD, following the introduction of WB-Taqman. METHODS: A total of 192 patients (WB-Taqman) with possible or probable MCD, including those admitted to our paediatric intensive care unit, were studied. Admission EDTA samples obtained were sent for bacterial DNA detection at the Meningococcal Reference Unit (MRU), Manchester. These patients were compared to 319 patients with possible and probable MCD, seen at the same hospital prior to the introduction of WB-Taqman. RESULTS: Following the introduction of WB-Taqman, 82 of the 95 probable cases (88%) had a positive meningococcal PCR result. This gives a diagnostic sensitivity and specificity for WB-Taqman of 87% and 100% respectively. Following WB-Taqman all blood culture positive patients were also PCR positive. Confirmation of cases by PCR rose from 47% (S-Taqman, n = 166) to 88% (WB-Taqman). When all confirmatory tests were included, case confirmation increased from 72% (S-Taqman) to 94% (WB-Taqman). CONCLUSION: The sensitivity of PCR in confirming clinical MCD has improved significantly with this new method. The gold standard for confirming cases of MCD is now the WB-Taqman PCR.

Meningococcal bacterial DNA load at presentation correlates with disease severity.

AIMS: To determine bacterial loads in meningococcal disease (MCD), their relation with disease severity, and the factors which determine bacterial load. METHODS: Meningococcal DNA quantification was performed by the Taqman PCR method on admission and sequential blood samples from patients with MCD. Disease severity was assessed using the Glasgow Septicaemia Prognostic Score (GMSPS, range 0-15, severe disease > or =8). RESULTS: Median admission bacterial load was 1.6 x 10(6) DNA copies/ml of blood (range 2.2 x 10(4) to 1.6 x 10(8)). Bacterial load was significantly higher in patients with severe (8.4 x 10(6)) compared to milder disease (1.1 x 10(6), p = 0.018). This difference was greater in septicaemic patients (median 1.6 x 10(7) versus 9.2 x 10(5), p < 0.001). Bacterial loads were significantly higher in patients that died (p = 0.017). Admission bacterial load was independent of the duration of clinical symptoms prior to admission, with no difference between the duration of symptoms in mild or severe cases (median, 10.5 and 11 hours respectively). Bacterial loads were independent of DNA elimination rates following treatment. CONCLUSION: Patients with MCD have higher bacterial loads than previously determined with quantitative culture methods. Admission bacterial load is significantly higher in patients with severe disease (GMSPS > or =8) and maximum load is highest in those who die. Bacterial load is independent of the duration of clinical symptoms or the decline in DNA load.

Cytokines, chemokines and other effector molecules involved in meningococcal disease.

This review examines the role of cytokines and chemokines in the pathogenesis of meningococcal disease (MCD) and draws comparisons with studies of other forms of sepsis in adults and in animal models. There are many similarities but also discrepancies between these data. MCD is a well-defined clinical syndrome with identifiable onset and time of presentation. It is a reliable model in which to study cytokine and chemokine responses in bacterial sepsis. Such studies may lead to new adjunctive treatments, which can be tested to ameliorate severe MCD.

Molecular phylogenetics and biogeography of tanagers in the genus Ramphocelus (Aves).

Ramphocelus tanagers are distributed throughout the Neotropical lowlands. In this paper, mitochondrial DNA (mtDNA) sequence data from cytochrome b and ND2 genes are used to estimate relationships among seven of nine species of the avian genus Ramphocelus. Genetic differentiation is high between Ramphocelus passerinii passerinii and Ramphocelus passerinii costaricensis, and the two subspecies are diagnosable and distinct from one another both morphologically and genetically. Thus, elevation to species status is recommended. Three clades are supported by both gene sequences; one clade contains R. passerinii, R. costaricensis, and R. icteronotus; the second clade contains Ramphocelus carbo, Ramphocelus bresilius, and Ramphocelus nigrogularis; the third clade contains Ramphocelus sanguinolentus. The degree of saturation was assessed for both genes and saturation of third position of codons occurs by 10-12% uncorrected pairwise sequence divergence. The general area cladogram suggests the following area relationships: Pacific and Caribbean Central America are sister areas, Chocó is the sister to the Central American area, and Amazonia/southeastern Brazil is the outgroup area to the Chocó/Central American clade.