Health officials’ perceptions of and preparedness for the impacts of climate variability on human health in the Somali region of Ethiopia

A proactive strategy to respond effectively to health impacts related to climate variability, particularly within vulnerable populations, is of vital importance. Such a strategy can be attained if health officials have a deep understanding of how climate variability affects human health and if the resources available for the health care sector are sufficient. This study assessed the perceptions and preparedness of health officials toward climate variability and health impacts in the Somali region of Ethiopia. The resources available for the health care sector were also assessed. The results show that approximately 80% of health officials were aware of the relationship between climate variability and human health impacts, but the majority of them were unable to project the future trend of related health problems in the region. The results also show an inadequate availability of health care resources, particularly in regards to infrastructure, numbers of health professionals, and training on climate variability and health. The results further revealed problems with poor living conditions, such as access to sanitation and safe water, for the majority of people in the study area. Climate variability is thus one of the many factors exacerbating the increasing trend of human health problems in the Somali region. Besides improving training to increase health officials’ knowledge of climate variability and human health impacts, the government should also address other factors that currently hinder a successful response to increasing disease prevalence.     

Managing the cost of emissions for durable,carbon-containing products

We recognize that carbon-containing products do not decay and release CO₂ to the atmosphere instantaneously, but release that carbon over extended periods of time. For an initial production of a stock of carbon-containing product, we can treat the release as a probability distribution covering the time over which that release occurs. The probability distribution that models the carbon release predicts the amount of carbon that is released as a function of time. The use of a probability distribution in accounting for the release of carbon to the atmosphere realizes a fundamental shift from the idea that all carbon-containing products contribute to a single pool that decays in proportion to the size of the stock. Viewing the release of carbon as a continuous probabilistic process introduces some theoretical opportunities not available in the former paradigm by taking advantage of other fields where the use of probability distributions has been prevalent for many decades. In particular, theories developed in the life insurance industry can guide the development of pricing and payment structures for dealing with the costs associated with the oxidation and release of carbon. These costs can arise from a number of proposed policies (cap and trade, carbon tax, social cost of carbon, etc), but in the end they all result in there being a cost to releasing carbon to the atmosphere. If there is a cost to the emitter for CO₂ emissions, payment for that cost will depend on both when the emissions actually occur and how payment is made. Here we outline some of the pricing and payment structures that are possible which result from analogous theories in the life insurance industry. This development not only provides useful constructs for valuing sequestered carbon, but highlights additional motivations for employing a probability distribution approach to unify accounting methodologies for stocks of carbon containing products.     

Impact of Drip Irrigation Method,Soil, and Virus Type on Tomato and Cucumber Contamination

The goal of this study was to better quantify the degree of viral contamination of tomato and cucumber in relationship to virus type, soil type, and irrigation method. Tomatoes and cucumbers were grown in ten-gallon (37.8 L) buckets filled with Pima clay loam or Brazito sandy loam soils. Plants were irrigated with secondary wastewater effluent using surface drip irrigation or subsurface drip irrigation. At specified time intervals irrigation water was seeded with bacteriophages MS-2 and P22, poliovirus type 1 (PV1), enteric adenovirus 40 (Ead 40), and hepatitis A virus. Surface drip irrigation always resulted in viral contamination of both the above and below ground parts of both crops. The roots showed the greatest level of contamination, followed by leaves and fruits. In contrast, with subsurface drip irrigation no viruses were detected in any of the above ground plant surfaces. It was found that under similar soil type and irrigation method, risk of crop contamination was similar for all of the viruses studied. It can be concluded that method of irrigation is the single most critical factor in the contamination trend of different parts of crop plants. Plant parts can be categorized into three groups (root, stem, and leaf/fruit) based on the risk of viral contamination from irrigation water.     

Application of Pesticide Sprays to Fresh Produce: A Risk Assessment for Hepatitis A and <Emphasis Type="Italic">Salmonella</Emphasis>

The purpose of this study was to quantify the transfer of viral and bacterial pathogens in water used to dilute pesticides sprayed onto the surfaces of cantaloupe, iceberg lettuce, and bell peppers. The average percent transfer of bacteria was estimated to range from 0.00021 to 9.4%, while average viral transfer ranged from 0.055 to 4.2%, depending on the type of produce. Based on these values the concentrations of hepatitis A virus (HAV) and Salmonella in water necessary to achieve a 1:10,000 annual risk of infection were calculated. Under worst case scenario assumptions, in which a pesticide is applied on the same day that the produce is harvested and when maximum transfer values are used, concentrations of 1.5 × 10⁻³ CFU Salmonella or 2.7 × 10⁻⁷ MPN HAV per 100 ml of the water used for application would result in 1:10,000 annual infection risk to anyone who consumes the fresh produce. If harvesting does not occur until at least 14 days after the application, to produce the same risk of infection, the numbers of Salmonella in 100 ml of water used to dilute the pesticides will be greater by up to five orders of magnitude, while the HAV numbers will have increased by up to two orders of magnitude. Based on the reported concentrations of enteric viruses in surface and ground waters in the United States, a 1:10,000 annual risk of infection could easily be exceeded with some groundwater sources used in the United States. To reduce the risks associated with the consumption of fresh produce, water used to prepare pesticides in spray applications should be evaluated for its microbiological quality.     

Solar Disinfection of Water for Inactivation of Enteric Viruses and its Enhancement by Riboflavin

Solar disinfection (SODIS) has been described as a cheap and effective method of treating contaminated water to inactivate pathogenic microorganisms. In this study, SODIS was assessed for its efficacy in inactivating three enteric viruses (coxsackievirus B3, coxsackievirus B5 and poliovirus), either on its own or in the presence of riboflavin as a disinfection enhancer. On its own, SODIS produced a reduction of virus infectivity of 4–6 log₁₀ in 6 h. In the presence of riboflavin, inactivation was more rapid in all viruses studied, and with coxsackievirus B5 and poliovirus an extra 1–2 log₁₀ increase in reduction of infectivity was observed after 6 h exposure. This study provides a practical example of low technology methods which could be utilised to provide safe drinking water in various circumstances.     

Influence of cation type, ionic strength, and pH on solubilization and mobilization of residual hydrocarbon by a biosurfactant

This study investigated the effect of cation type, ionic strength, and pH on the performance of an anionic monorhamnolipid biosurfactant for solubilization and removal of residual hexadecane from sand. Three common soil cations, Na⁺, Mg²⁺, and Ca²⁺, were used in these experiments and hexadecane was chosen to represent a nonaqueous phase liquid (NAPL) less dense than water. Results showed that hexadecane solubility in rhamnolipid solution was significantly increased by the addition of Na⁺ and Mg²⁺. Addition of up to 0.2 mM Ca²⁺ also increased hexadecane solubility. For Ca²⁺ concentrations greater than 0.2 mM there was little effect on hexadecane solubility due to competing effects of calcium-induced rhamnolipid precipitation and enhanced hexadecane solubilization. Efficiency of NAPL solubilization can be expressed in terms of molar solubilization ratios (MSR). The results showed that MSR values for hexadecane in rhamnolipid solutions increased 7.5-fold in the presence of 500 mM Na⁺, and 25-fold in the presence of 1 mM Mg²⁺. The presence of cations also reduced the interfacial tension between rhamnolipid solutions and hexadecane. For example, an increase in Na⁺ from 0 to 800 mM caused a decrease in interfacial tension from 2.2 to 0.89 dyn cm⁻¹. Similarly, decreasing pH caused a reduction in interfacial tension. The lowest interfacial tension value observed in this study was 0.02 dyn cm⁻¹ at pH 6 in the presence of 320 mM Na⁺. These conditions were also found to be optimal for removal of hexadecane residual from sand columns, with 58% of residual removed within three pore volumes. The removal of residual NAPL from the packed columns was primarily by mobilization, even though solubilization was significantly increased in the presence of Na⁺.     

Vigilance in wild Thomas's langurs (Presbytis thomasi ): the importance of infanticide risk

This study examines vigilance as a behavioural indicator of the importance of infanticide risk by comparing the infanticide avoidance hypothesis with the predation avoidance and mate defence hypotheses for wild Thomas's langurs (Presbytis thomasi) in Sumatra. We found that all individuals were more vigilant in situations of high predation risk, i.e. lower in the trees and in the absence of neighbours. Females were also more vigilant on the periphery of the group. However, there were variations in vigilance levels that could not be accounted for by the predation avoidance hypothesis. Males without infants showed higher levels of vigilance in areas of home range overlap than in non-overlap areas during the early phase of their tenure, strongly suggesting mate defence. In these areas of home range overlap where Thomas's langur groups can interact, males may attack females and infants, and so the infanticide risk for males and females with infants is likely to be high in these areas. Only females with infants, but not males with infants or females without infants, showed higher vigilance levels in overlap areas than in non-overlap areas; in addition, in overlap areas, females with an infant were more vigilant than females without an infant, while this was not the case in non-overlap areas. Both females and males with infants were more vigilant high in the trees than at medium heights in overlap areas but not elsewhere. These findings can only be explained by the infanticide avoidance hypothesis. In contrast to predator attacks, infanticidal male attacks come from high in the canopy, and only occur in overlap areas. There was a significant sex difference in vigilance, but males were only more vigilant than females without an infant, and not more vigilant than females with an infant. We conclude that vigilance varied mainly in relation to the risk of predation and infanticide. Mate competition only played a role for males during the early phase of their tenure. Predation risk seems to offer the best explanation for vigilance for all individuals in the absence of infants. Both predation risk and infanticide risk played a role for females and males with infants. Received: 4 April 1998 / Accepted after revision: 6 September 1998