973 research outputs found
Environmental monitoring of Mycobacterium bovis in badger feces and badger sett soil by real-time PCR, as confirmed by immunofluorescence, immunocapture, and cultivation
Real-time PCR was used to detect and quantify Mycobacterium bovis cells in
naturally infected soil and badger faeces. Immunomagnetic capture,
immunofluorescence and selective culture confirmed species identification and cell
viability. These techniques will prove useful for monitoring M. bovis in the
environment and for elucidating transmission routes between wildlife and cattle
Performance of an environmental test to detect Mycobacterium bovis infection in badger social groups
A study by Courtenay and others (2006) demonstrated that
the probability of detecting Mycobacterium bovis by PCR in
soil samples from the spoil heaps of main badger setts correlated
with the prevalence of excretion (infectiousness) of
captured badgers belonging to the social group. It has been
proposed that such a test could be used to target badger culling
to setts containing infectious animals (Anon 2007). This
short communication discusses the issues surrounding this
concept, with the intention of dispelling any misconceptions
among relevant stakeholders (farmers, policy makers and
conservationists)
Heterogeneities in leishmania infantum infection : using skin parasite burdens to identify highly infectious dogs
Background: The relationships between heterogeneities in host infection and infectiousness (transmission to arthropod vectors) can provide important insights for disease management. Here, we quantify heterogeneities in Leishmania infantum parasite numbers in reservoir and non-reservoir host populations, and relate this to their infectiousness during natural infection. Tissue parasite number was evaluated as a potential surrogate marker of host transmission potential.
Methods: Parasite numbers were measured by qPCR in bone marrow and ear skin biopsies of 82 dogs and 34 crab-eating foxes collected during a longitudinal study in Amazon Brazil, for which previous data was available on infectiousness (by xenodiagnosis) and severity of infection.
Results: Parasite numbers were highly aggregated both between samples and between individuals. In dogs, total parasite abundance and relative numbers in ear skin compared to bone marrow increased with the duration and severity of infection. Infectiousness to the sandfly vector was associated with high parasite numbers; parasite number in skin was the best predictor of being infectious. Crab-eating foxes, which typically present asymptomatic infection and are non-infectious, had parasite numbers comparable to those of non-infectious dogs.
Conclusions: Skin parasite number provides an indirect marker of infectiousness, and could allow targeted control particularly of highly infectious dogs
The potential influence of masculine identity on health-improving behavior in midlife and older African American men
http://dx.doi.org/10.1016/j.jomh.2012.02.00
Reference evapotranspiration from coarse-scale and dynamically downscaled data in complex terrain: Sensitivity to interpolation and resolution
The main objective of this study was to investigate whether dynamically downscaled high resolution (4-km) climate data from the Weather Research and Forecasting (WRF) model provide physically meaningful additional information for reference evapotranspiration (E) calculation compared to the recently published GridET framework that uses interpolation from coarser-scale simulations run at 32-km resolution. The analysis focuses on complex terrain of Utah in the western United States for years 1985–2010, and comparisons were made statewide with supplemental analyses specifically for regions with irrigated agriculture. E was calculated using the standardized equation and procedures proposed by the American Society of Civil Engineers from hourly data, and climate inputs from WRF and GridET were debiased relative to the same set of observations. For annual mean values, E from WRF (EW) and E from GridET (EG) both agreed well with E derived from observations (r2 = 0.95, bias \u3c 2 mm). Domain-wide, EW and EG were well correlated spatially (r2 = 0.89), however local differences ΔE=EW-EG were as large as +439 mm year−1 (+26%) in some locations, and ΔE averaged +36 mm year−1. After linearly removing the effects of contrasts in solar radiation and wind speed, which are characteristically less reliable under downscaling in complex terrain, approximately half the residual variance was accounted for by contrasts in temperature and humidity between GridET and WRF. These contrasts stemmed from GridET interpolating using an assumed lapse rate of Γ = 6.5K km−1, whereas WRF produced a thermodynamically-driven lapse rate closer to 5K km−1 as observed in mountainous terrain. The primary conclusions are that observed lapse rates in complex terrain differ markedly from the commonly assumed Γ = 6.5K km−1, these lapse rates can be realistically resolved via dynamical downscaling, and use of constant Γ produces differences in E of order as large as 102 mm year−1
- …