Body size has primacy over stoichiometric variables in nutrient excretion by a tropical stream fish community.

Ecological Stoichiometry (ES) and the Metabolic Theory of Ecology (MTE) are the main theories used to explain consumers' nutrient recycling. ES posits that imbalances between an animal's body and its diet stoichiometry determine its nutrient excretion rates, whereas the MTE predicts that excretion reflects metabolic activity arising from body size and temperature. We measured nitrogen, phosphorus and N:P excretion, body N:P stoichiometry, body size, and temperature for 12 fish species from a Brazilian stream. We fitted competing models reflecting different combinations of ES (body N:P, armor classification, diet group) and MTE (body size, temperature) variables. Only body size predicted P excretion rates, while N excretion was predicted by body size and time of day. N:P excretion was not explained by any variable. There was no interspecific difference in size-scaling coefficients neither for N nor for P. Fitted size scaling coefficients were lower than the MTE prediction of 0.75 for N (0.58), and for P (0.56). We conclude that differences in nutrient excretion among species within a shared environment primarily reflect contrasts in metabolic rates arising from body size, rather than disparities between consumer and resource stoichiometry. Our findings support the MTE as the primary framework for predicting nutrient excretion rates.

Changing Patterns of Pertussis in a Children's Hospital in the Polymerase Chain Reaction Diagnostic Era.

OBJECTIVE: To assess changes in diagnostic practice and vaccine schedules for pertussis, we used culture-confirmation and clinical severity to compare pertussis cases at a single Australian tertiary pediatric hospital during relevant periods. STUDY DESIGN: We replicated the case ascertainment methods of a study reporting a 2-year epidemic period 1997-1999 (whole cell pertussis vaccine with 18-month booster, only culture available) to conduct a retrospective cross-sectional observational study over a 6-year period 2007-2012 (acellular pertussis vaccine, no 18-month booster, polymerase chain reaction and culture available). Cases were compared from case note review 2007-2012 (including prevalence of comorbidities) and published data 1997-1999. RESULTS: During 2007-2012, average annual hospitalizations in those aged < 6 months increased 2.3-fold (32.0 vs 14.0) and in those aged > 6 months by 5.1-fold (17.7 vs 3.5). Limited to culture-positive hospitalizations, there was no increase in those aged < 6 months (14.0 vs 14.5) contrasted with a 4.6-fold increase in those aged > 6 months (2.3 vs 0.5), despite increased annual culture requests (488 vs 188). In 2007-2012, significant comorbidities were documented in 41/72 (57%) hospitalized children aged ≥ 12 months vs 38/225 (17%) <12 months (OR 6.5, 95% CI 3.7-11.7). CONCLUSIONS: Increased cases of culture-positive hospitalized pertussis were limited to fully immunized children > 6 months of age, consistent with schedule changes. Significant comorbidities were common, making a booster dose at 12-18 months of age especially important.

Mercury biomagnification in the food web of a neotropical stream.

Anthropogenic and natural mercury (Hg) contamination have been a major concern in South America since the early 1900s, but it remains unclear whether Hg levels pose a hazard to human health in regions that lack point sources. We studied Hg biomagnification patterns in the food web of Río Las Marías, an Andean piedmont stream in northern Venezuela, which supports a major subsistence fishery. Mercury concentrations and trophic positions in the food web (based on stable isotopes of nitrogen and carbon) were characterized for 24 fish species representing seven trophic guilds (piscivore, generalized carnivore, omnivore, invertivore, algivore, terrestrial herbivore, detritivore). Mercury showed significant biomagnification through the food web, but vertical trophic position explained little of the variation. Muscle Hg concentrations also increased with body mass across the food web. Trophic guild assignments offered a useful alternative to explicit analysis of vertical trophic position; piscivores showed the highest Hg concentrations and terrestrial herbivores had the lowest. There were no consistent seasonal differences in Hg concentrations within the 5 species sampled during both the wet and dry seasons, suggesting that bioavailability is unaffected by strong seasonal variation in rainfall. From a human health perspective, many medium- to large-bodied species that are commonly eaten had Hg concentrations that exceeded International Marketing Limit (IML) (0.5 µg/g) and World Health Organization (WHO) guidelines (0.2 µg/g) for consumption. We conclude that Hg concentrations may pose a health concern for local subsistence fishermen and their families. Our results suggest a need to perform risk assessment and better understand contaminant levels in subsistence and commercial fisheries even in areas that lack known Hg point sources.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND: Live attenuated varicella vaccines for the prevention of varicella (chickenpox) has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States. However, many countries do not routinely immunise children against varicella, and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP). OBJECTIVE: To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults. CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008, Issue 1); MEDLINE (1966 to February 2008); and EMBASE (January 1990 to February 2008). SELECTION CRITERIA: RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse effects following vaccination. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted and analysed data using Review Manager software. MAIN RESULTS: Three studies involving 110 healthy children who were siblings of household contacts were identified as suitable for inclusion. The studies varied in quality, study design, vaccine used, and outcomes measured and, as such, were not suitable for meta-analysis. Overall, 13 out of 56 vaccine recipients (18%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with less than 50 skin lesions). In the three studies, most subjects received PEP within three days following exposure; too few subjects were vaccinated four to five days post exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included studies reported on adverse events following immunisation. AUTHORS CONCLUSIONS: These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. No RCTs for adolescents or adults were identified. However safety was not adequately addressed.

The population and reproductive health programme in Brazil 1990-2002: lessons learned.

The story of Brazil's evolution in sexual and reproductive health and rights during the 1990s documents not only a decade of change in the population field, but the powerful role of social movements in a democracy. Between October and December 2002, 23 people were interviewed about where they believe progress has been made in Brazil and where there are still needs in relation to population trends, sexual and reproductive rights, and health policies. This paper contains excerpts from the full report and covers the economic and political background of Brazil; the role of non-governmental and women's organisations in influencing the national agenda; the intersection of national and international agendas on population and development, HIV/AIDS, human rights, racism and other issues; changes in sexual and reproductive health policies; HIV/AIDS policy progress, perhaps most importantly mandatory free treatment for people with HIV/AIDS; recent progress in women's health, especially in relation to antenatal and obstetric services, and services addressing violence against women. Finally it describes the role of policy accountability mechanisms that aim to ensure that the many excellent policies that have been passed since 1990 are implemented in a decentralised health system of national, state and local management and services.

Effects of behavioral and morphological plasticity on risk of predation in a Neotropical tadpole.

Predator-induced phenotypic plasticity is widespread among aquatic animals, however the relative contributions of behavioral and morphological shifts to reducing risk of predation remain uncertain. We tested the phenotypic plasticity of a Neotropical tadpole ( Rana palmipes) in response to chemical cues from predatory Belostoma water bugs, and how phenotype affects risk of predation. Behavior, morphology, and pigmentation all were plastic, resulting in a predator-induced phenotype with lower activity, deeper tail fin and muscle, and darker pigmentation. Tadpoles in the predator cue treatment also grew more rapidly, possibly as a result of the nutrient subsidy from feeding the caged predator. For comparison to phenotypes induced in the experiment, we quantified the phenotype of tadpoles from a natural pool. Wild-caught tadpoles did not match either experimentally induced phenotype; their morphology was more similar to that produced in the control treatment, but their low swimming activity was similar to that induced by predator cues. Exposure of tadpoles from both experimental treatments and the natural pool to a free-ranging predator confirmed that predator-induced phenotypic plasticity reduces risk of predation. Risk of predation was comparable among wild-caught and predator-induced tadpoles, indicating that behavioral shifts can substantially alleviate risk in tadpoles that lack the typical suite of predator-induced morphological traits. The morphology observed in wild-caught tadpoles is associated with rapid growth and high competition in other tadpole species, suggesting that tadpoles may profitably combine a morphology suited to competition for food with behaviors that minimize risk of predation.