Rapid assessment of injection practices in Cambodia, 2002

BACKGROUND: Injection overuse and unsafe injection practices facilitate transmission of bloodborne pathogens such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Anecdotal reports of unsafe and unnecessary therapeutic injections and the high prevalence of HBV (8.0%), HCV (6.5%), and HIV (2.6%) infection in Cambodia have raised concern over injection safety. To estimate the magnitude and patterns of such practices, a rapid assessment of injection practices was conducted. METHODS: We surveyed a random sample of the general population in Takeo Province and convenience samples of prescribers and injection providers in Takeo Province and Phnom Penh city regarding injection-related knowledge, attitudes, and practices. Injection providers were observed administering injections. Data were collected using standardized methods adapted from the World Health Organization safe injection assessment guidelines. RESULTS: Among the general population sample (n = 500), the overall injection rate was 5.9 injections per person-year, with 40% of participants reporting receipt of ≥ 1 injection during the previous 6 months. Therapeutic injections, intravenous infusions, and immunizations accounted for 74%, 16% and 10% of injections, respectively. The majority (>85%) of injections were received in the private sector. All participants who recalled their last injection reported the injection was administered with a newly opened disposable syringe and needle. Prescribers (n = 60) reported that 47% of the total prescriptions they wrote included a therapeutic injection or infusion. Among injection providers (n = 60), 58% recapped the syringe after use and 13% did not dispose of the used needle and syringe appropriately. Over half (53%) of the providers reported a needlestick injury during the previous 12 months. Ninety percent of prescribers and injection providers were aware HBV, HCV, and HIV were transmitted through unsafe injection practices. Knowledge of HIV transmission through "dirty" syringes among the general population was also high (95%). CONCLUSION: Our data suggest that Cambodia has one of the world's highest rates of overall injection usage, despite general awareness of associated infection risks. Although there was little evidence of reuse of needles and syringes, support is needed for interventions to address injection overuse, healthcare worker safety and appropriate waste disposal

Review of the transition From smouldering to flaming combustion in wildfires

Wildfires are uncontrolled combustion events occurring in the natural environment (forest, grassland, or peatland). The frequency and size of these fires are expected to increase globally due to changes in climate, land use, and population movements, posing a significant threat to people, property, resources, and the environment. Wildfires can be broadly divided into two types: smouldering (heterogeneous combustion) and flaming (homogeneous combustion). Both are important in wildfires, and despite being fundamentally different, one can lead to the other. The smouldering-to-flaming (StF) transition is a quick initiation of homogeneous gas-phase ignition preceded by smouldering combustion, and is considered a threat because the following sudden increase in spread rate, power, and hazard. StF transition needs sufficient oxygen supply, heat generation, and pyrolysis gases. The unpredictable nature of the StF transition, both temporally and spatially, poses a challenge in wildfire prevention and mitigation. For example, a flaming fire may rekindle through the StF transition of an undetected smouldering fire or glowing embers. The current understanding of the mechanisms leading to the transition is poor and mostly limited to experiments with samples smaller than 1.2 m. Broadly, the literature has identified the two variables that govern this transition, i.e., oxygen supply and heat flux. Wind has competing effects by increasing the oxygen supply, but simultaneously increasing cooling. The permeability of a fuel and its ability to remain consolidated during burning has also been found to influence the transition. Permeability controls oxygen penetration into the fuel, and consolidation allows the formation of internal pores where StF can take place. Considering the high complexity of the StF transition problem, more studies are needed on different types of fuel, especially on wildland fuels because most studied materials are synthetic polymers. This paper synthesises the research, presents the various StF transition characteristics already in the literature, and identifies specific topics in need of further research

Laboratory study on the suppression of smouldering peat wildfires: effects of flow rate and wetting agent

The application of water, or water mixed with suppressants, to combat wildfires is one of the most common firefighting methods but is rarely studied for smouldering peat wildfire, which is the largest type of fire worldwide in term of fuel consumption. We performed experiments by spraying suppressant to the top of a burning peat sample inside a reactor. A plant-based wetting agent suppressant was mixed with water at three concentrations: 0% (pure water), 1% (low concentration), and 5% (high concentration), and delivered with varying flowrates. The results showed that suppression time decreased non-linearly with flow rate. The average suppression time for the low-concentration solution was 39% lower than with just water, while the high-concentration solution reduced suppression time by 26%. The volume of fluid that contributes to the suppression of peat in our experiments is fairly constant at 5.7 ± 2.1 L kg−1 peat despite changes in flow rate and suppressant concentration. This constant volume suggests that suppression time is the duration needed to flood the peat layer and that the suppressant acts thermally and not chemically. The results provide a better understanding of the suppression mechanism of peat fires and can improve firefighting and mitigation strategies