Moving towards universal coverage with malaria control interventions: achievements and challenges in rural Burkina Faso

This paper reports on a study, which assessed coverage with malaria control interventions in rural Burkina Faso, namely insecticide‐treated mosquito nets (ITN) ownership, intermittent preventive treatment (IPTp) for pregnant women and artemisinin‐based combination therapy (ACT) for under‐five children. The study also addressed the distributional impact of such interventions, with specific reference to equity. The study used data from a representative household survey conducted on 1106 households in the Nouna Health District in 2010. Findings indicated that 59% of all households owned at least one ITN, 66% of all pregnant women received IPT at least once and 34% of under‐five children reporting a malaria case were treated with ACT. Multivariate logistic regression revealed that higher socio‐economic status, ownership of at least one radio and living in a village within a Health and Demographic Surveillance System were significantly positively associated with ITN, IPTp and ACT coverage. ITN coverage was higher among households in villages, which had previously hosted an ITN trial and/or the most favourable arm of a trial. Comparing current findings with previous estimates suggests that the country has made substantial progress towards scaling up malaria control interventions but that current coverage rates are still far from achieving the universal coverage targets set by the Roll Back Malaria Partnership. In addition, current coverage patterns reveal the existence of multiple inequities across groups, suggesting that current policies are inadequate to achieve equitable scaling up. Future planning of malaria control interventions ought to take into consideration current inadequacies and lead to programmes better designed to overcome them. Copyright © 2012 John Wiley & Sons, Ltd.     

Spatio-temporal modeling of sparse geostatistical malaria sporozoite rate data using a zero inflated binomial model

The proportion of malaria vectors harboring the infectious stage of the parasite (the sporozoite rates) is an important component of measures of malaria transmission. Variation in time and/or space in sporozoite rates contribute substantially to spatio-temporal variation in transmission. However, because most vectors test negative for sporozoites, sporozoite rate data are sparse with large number of observed zeros across locations or over time in the case of longitudinal data. Rarely are appropriate methods and models used in analyzing such data. In this study, Bayesian zero inflated binomial (ZIB) geostatistical models were developed and compared with standard binomial analogues to analyze sporozoite data obtained from the KEMRI/CDC health and demographic surveillance system (HDSS) site in rural Western Kenya during 2002-2004. ZIB models showed a better predictive ability, identified more significant covariates and obtained narrower credible intervals for all parameters compared to standard geostatistical binomial model.     

Cost of malaria control in Sri Lanka.

The study provides estimates of the cost of various malaria control measures in an area of North-Central Province of Sri Lanka where the disease is endemic. We assumed that each measure was equally effective. In these terms, impregnating privately purchased bednets with insecticide was estimated to cost Rs 48 (US(40.87) per individual protected per year, less than half the cost of spraying houses with residual insecticides. Larviciding of vector breeding sites and especially the elimination of breeding habitats by flushing streams through seasonal release of water from upstream reservoirs was estimated to be cheaper than other preventive measures (Rs 27 (US$ 0.49) and Rs 13 (US$ 0.24) per individual protected, respectively). Inclusion of both operational and capital costs of treatment indicates that the most cost-effective intervention for the government was a centrally located hospital with a relatively large catchment area (Rs 71 (US$ 1.29) per malaria case treated). Mobile clinics (Rs 153 (US$ 2.78) per malaria case treated) and a village treatment centre (Rs 112 (US$ 2.04)) per malaria case treated) were more expensive options for the government, but were considerably cheaper for households than the traditional hospital facilities. This information can guide health planners and government decision-makers in choosing the most appropriate combination of curative and preventive measures to control malaria. However, the option that is cheapest for the government may not be so for the householders, and further studies are needed to estimate the effectiveness of the various preventive measures.     

Spatial patterns of malaria in the Amazon: implications for surveillance and targeted interventions

A measure of local spatial association, G(i)*(d), is applied to test for the presence of malaria clusters in a colonization area in the Brazilian Amazon. Clusters of high and low malaria rates at different moments in time are identified. They suggest unambiguous spatial patterns of transmission, most likely linked to the social and natural habitat. Results imply that a comprehensive identification of the determinants of malaria transmission requires a spatial framework of analysis, and that control strategies must be spatially targeted and guided by a surveillance system that constantly learns the specificities of local transmission and adapts interventions to them.     

The economic consequences of malaria for households: a case-study in Nepal

Increased attention has recently been paid to the impact of illness on the well-being of households in developing countries. This has been a particular theme in the case of malaria, but relatively little evidence is available on how households react to malaria and on its impact on expenditure and time allocation patterns. This paper reports the results of a study designed to investigate the economic consequences of malaria for households in Nepal. A household survey of malaria cases in two districts provided information on use of various sources of treatment, their cost to households, time lost by the person with malaria, the extent to which others inside or outside the household provided assistance with the normal work of the malaria patient, the time spent caring for a child with malaria and any financial losses associated with the malaria episode. Out-of-pocket expenditure on treatment differed greatly between the two districts, for reasons associated with the choice of public or private sources of treatment and the number of visits made per episode. The majority of households appeared to cope without great difficulty with the reduction in labour supply caused by a malaria episode, by drawing largely on the time of adult family members. Caution is advised in extrapolating the results to other situations, given the extent to which local factors are likely to influence the impact on households. Moreover, the findings relate to a situation where a malaria control programme is in place: a relatively greater impact per household would occur in the absence of control. However, it is argued that such surveys have value in informing health policy, particularly in relation to setting priorities and treatment policy.     

Modeling of malaria incidence in Nepal

Background: Malaria is a major cause of morbidity and mortality in Nepal. The magnitude of malaria across the country is alarming and varies with location. Therefore, the present study aimed to model malaria incidence rates during 1998 to 2009 in Nepal. Methods: Data for the study were obtained from Health Management Information System (HMIS), Ministry of Public Health. A negative binomial model was used to fit malaria incidence rates as a function of year and location and provided a good fit, as indicated by residual plots. Results: In total, 83,345 cases of malaria were reported from 1998 to 2009. The mean incidence rate was 0.30 per 1000 population. The models show trends and spatial variations in disease incidence. There was decreasing trend in the incidence rates of malaria (1998-2004), followed by a more moderate upward trend until 2008, when the rate decreases again. Zero malaria incidences occurred in six districts including Humla, Jajarkot, Manang, Kathmandu, Bhakthapur and Solukhumbu districts for over twelve years. Higher incidence occurred in Kanchanpur, Kailali, Bardiya, Kavre, and Jhapa districts for the study period. Conclusion: Malaria is still a public health problem in Nepal. This study showed a steady decreasing trend in malaria incidence but the numbers of cases are still very high. Higher rates were observed in Terai Region and border areas. These findings highlight the need for more systematic and effective malaria control measures on malaria burden areas of Nepal.     

Acinetobacter outbreaks, 1977-2000.

This review of Acinetobacter outbreaks summarizes factors related to the presence and recognition of organism transmission and describes the implementation of control and prevention measures directed at limiting spread. Exogenous transmission of Acinetobacter should be considered when infections are endemic and when case rates increase. Increasing or new antimicrobial resistances in a collection of isolates also suggest transmission, and transmission can be definitively confirmed when isolates are found to be indistinguishable from or related to one another by a discriminatory genotyping test. An investigation for a common source should be conducted. When a common source cannot be found and eliminated, or once an endemically transmitted organism is established, containment or prevention efforts may require aggressive interventions, complex interventions, or both. Colonization at multiple sites, the relative ease of induction of antibiotic resistance in the organism following patient exposure to multiple drugs, and long-term environmental survival provide enhanced opportunities for the transmission of Acinetobacter between and among patients. New approaches and interventional trials are needed to define effective measures for the prevention and control of Acinobacter infections.     

Impact and cost of infection control measures to reduce nosocomial transmission of extended-spectrum beta-lactamase-producing organisms in a non-outbreak setting

We evaluated the impact of infection control interventions to reduce nosocomial extended-spectrum beta-lactamase (ESBL) transmission in a non-outbreak setting. This study was conducted at a tertiary 1200-bed hospital in Canada. The incidence of ESBLs was based on recovery of clinical isolates and assessed prospectively from 1999 to 2005. The incidence increased significantly from 0.28 to 0.67 per 1000 admissions during this period (P<0.001), reflecting an increase in the regional ESBL incidence from 1.32 to 9.28 per 100 000 population (P<0.001). Despite this increase, nosocomial ESBL rates increased only marginally, suggesting that infection control measures had an impact on nosocomial transmission. Infection control measures consisted of isolating all ESBL patients, as well as implementing the use of contact precautions for those with a high risk for transmission. The cost of these measures was CN$138 046.00 per year and CN$3191.83 per case admitted. A combination of control measures including active surveillance cultures, contact precautions for all colonized or infected patients and antimicrobial stewardship is required to significantly reduce the incidence of ESBLs.     

An individual-based model of Plasmodium falciparum malaria transmission on the coast of Kenya

Individual-based models provide powerful tools to model complex interactions characterized by individual variability. This paper presents an object-oriented design for individual-based modelling of Plasmodium falciparum malaria transmission. Two kinds of objects, human and mosquito, that exhibit variability among individuals for parameters such as recovery and survival rates are defined. The model tracks the dynamics of human hosts and adult female mosquitoes individually. Immunity, modelled as a function of exposure history, is represented by reduced susceptibility and increased recovery rate. The model was calibrated using epidemiological data collected at 30 sites along the coast of Kenya. The sites were grouped into low, intermediate and high transmission based on mean daily human-biting rates. Simulation results show that malaria transmission was stable even in low transmission areas where the human-biting rate is approximately 0.5 bite per day. The model was used to examine the effect of infection control programmes that aim at interrupting transmission by reducing human-vector contact rates and implementing active case detection and drug treatment of infections. With this intervention, local elimination of malaria is likely with a probability of extinction of approximately 0.8 in low transmission areas. However, a small amount of immigration (> 0.3%) by infected people into the community could prevent local extinction of the parasite. In intermediate and high transmission areas, reduction in prevalence is short-lived and the probability of local elimination is low, even at high coverage levels of the intervention.     

应用间接荧光抗体技术进行疟疾纵向调查

应用恶性疟原虫与食蟹猴疟原虫两种抗原作间接荧光抗体试验,1983~1984年间对安徽省三个采取不同抗疟措施的间日疟与恶性疟混合流行区进行了两年的纵向调查,血清学结果与疟原虫率调查结果在反映疟疾不同的流行水平上显示平行的关系。三个地区每年疟疾传播季节的寄生虫学接种率(疟原虫血症发生率)与恢复率,食蟹猴疟原虫与恶性疟原虫抗原检测的疟疾抗体阳性发生率与恢复率,其数值大小与变动分别与该地间日疟与恶性疟的传播强度及采取的抗疟惜施相关。     

山东省灭疟后期影响疟疾传播的社会经济因素分析

以山东省1990～1993年确诊的全部疟疾病人为研究对象,采用1:2配对病例对照设计,经单因素和多因素分析对灭疟后期影响疟疾传播的社会经济因素进行了筛选。结果发现,去过或来自疟区、家庭经济状况差、住房靠近媒介孳生地、卧室无纱窗和纱门以及黄昏野外作业与疟疾发病有关,从而可为当前制定适宜的疟防措施提供科学的理论依据。     

Possible Interruption of Malaria Transmission, Highland Kenya, 2007�C2008

Highland areas where malaria transmission is unstable are targets for malaria elimination because transmission decreases to low levels during the dry season. In highland areas of Kipsamoite and Kapsisiywa, Kenya (population ≈7,400 persons), annual household indoor residual spraying with a synthetic pyrethroid was performed starting in 2005, and artemether/lumefantrine was implemented as first-line malaria treatment in October 2006. During April 2007–March 2008, no microscopy-confirmed cases of malaria occurred at the sites. In 4 assessments of asymptomatic persons during May 2007–April 2008, a total of <0.3% of persons were positive for asexual Plasmodium falciparum by microscopy or PCR at any time, and none were positive by PCR at the last 2 sample collections. Our findings show that in such areas, interruption and eventual elimination of malaria transmission may be achievable with widespread annual indoor residual spraying of households and artemisinin combination therapy.     

Challenges to mapping the health risk of hepatitis A virus infection

Background

Geographic profiling is a statistical tool originally developed in criminology to prioritise large lists of suspects in cases of serial crime. Here, we use two data sets - one historical and one modern - to show how it can be used to locate the sources of infectious disease.

Results

First, we re-analyse data from a classic epidemiological study, the 1854 London cholera outbreak. Using 321 disease sites as input, we evaluate the locations of 13 neighbourhood water pumps. The Broad Street pump - the outbreak's source- ranks first, situated in the top 0.2% of the geoprofile. We extend our study with an analysis of reported malaria cases in Cairo, Egypt, using 139 disease case locations to rank 59 mosquitogenic local water sources, seven of which tested positive for the vector Anopheles sergentii. Geographic profiling ranks six of these seven sites in positions 1-6, all in the top 2% of the geoprofile. In both analyses the method outperformed other measures of spatial central tendency.

Conclusions

We suggest that geographic profiling could form a useful component of integrated control strategies relating to a wide variety of infectious diseases, since evidence-based targeting of interventions is more efficient, environmentally friendly and cost-effective than untargeted intervention.     

Individual,household and neighborhood risk factors for malaria in the Democratic Republic of the Congo support new approaches to programmatic intervention

BackgroundThe Democratic Republic of the Congo (DRC) remains one of the countries most impacted by malaria despite decades of control efforts, including multiple mass insecticide treated net (ITN) distribution campaigns. The multi-scalar and complex nature of malaria necessitates an understanding of malaria risk factors over time and at multiple levels (e.g., individual, household, community). Surveillance of households in both rural and urban settings over time, coupled with detailed behavioral and geographic data, enables the detection of seasonal trends in malaria prevalence and malaria-associated behaviors as well as the assessment of how the local environments within and surrounding an individual's household impact malaria outcomes.MethodsParticipants from seven sites in Kinshasa Province, DRC were followed for over two years. Demographic, behavioral, and spatial information was gathered from enrolled households. Malaria was assessed using both rapid diagnostic tests (RDT) and polymerase chain reaction (PCR) and seasonal trends were assessed. Hierarchical regression modeling tested associations between behavioral and environmental factors and positive RDT and PCR outcomes at individual, household and neighborhood scales.ResultsAmong 1591 enrolled participants, malaria prevalence did not consistently vary seasonally across the sites but did vary by age and ITN usage. Malaria was highest and ITN usage lowest in children ages 6–15 years across study visits and seasons. Having another member of the household test positive for malaria significantly increased the risk of an individual having malaria [RDT: OR = 4.158 (2.86–6.05); PCR: OR = 3.37 (2.41–4.71)], as did higher malaria prevalence in the 250 m neighborhood around the household [RDT: OR = 2.711 (1.42–5.17); PCR: OR = 4.056 (2.3–7.16)]. Presence of water within close proximity to the household was also associated with malaria outcomes.ConclusionsTaken together, these findings suggest that targeting non-traditional age groups, children >5 years old and teenagers, and deploying household- and neighborhood-focused interventions may be effective strategies for improving malaria outcomes in high-burden countries like the DRC.     

Accuracy of the health information system on malaria surveillance in Vietnam

The health information system (HIS) is a key component of control programs and its accuracy is necessary for the assessment of disease risks, the formulation of priorities and the evaluation of the cost-effectiveness of different interventions. In order to assess the quality of the HIS in estimating malaria morbidity in Vietnam, we compared data obtained by a 2-year active (ACD) and passive case detection (PCD) study with those routinely collected at the local commune health centres (CHC) at three sites having different malaria epidemiology. The majority of malaria cases (80-95%) detected by ACD were missed by the HIS. Similarly, most malaria cases (50-90%) detected by PCD were also missed by the HIS, and this was proportional to the number of active private practitioners. Reasons for this low sensitivity are low CHC attendance, high attendance at private health facilities, widespread self-medication and attendance at central health facilities. In conclusion, although malaria has sharply decreased in Vietnam over the past 10 years, the current HIS greatly underestimates the malaria burden. Involvement of the private sector and the establishment of sentinel sites might improve the quality of data and the relevance of HIS in malaria control.     

Perception of causes of malaria and treatment-seeking behaviour of nursing mothers in a rural community

OBJECTIVE: Maternal health care workers' recognition of malaria, its transmission and treatment of children's fever at community level. DESIGN: Randomised sampling of households with children of 0-5 years. SETTING: Rural community in a forest zone. Subjects: Fifty-five households at Ijegemo village, Ogun state, Nigeria were sampled and questionnaires administered to 200 mothers/care workers of children within the age group 0-5 years. Blood smears were obtained from finger pricks and level of parasitemia with malaria parasites determined for each child. MAIN OUTCOME MEASURES: Interactions with the women during the survey empowered them with accurate knowledge of malaria recognition, transmission and management of children's fever at the community level. RESULTS: Forty per cent of the respondents did not know the exact cause of malaria, 20% attributed the cause to sunlight, 16.5% to mosquitoes, 12.5% to poor hygiene, 4% to palm oil intake, 4% to blood shortage and 6% to a hot body. Of respondents 85.5% identified stagnant water as breeding site of mosquitoes but could not correlate it with the occurrence of malaria fever. Herbal concoction was the first treatment action. Some of these herbs are listed in the text. Plasmodium falciparum alone was identified in all blood smears. Children at two to three years of age were recorded with the highest percentage (67.5%) of parasite-positive cases with a mean value of 1237.04 +/- 2113.19. CONCLUSION: This study highlights a critical need for targeting health messages towards poorly educated women in order to empower them with the knowledge and resources to recognise and manage their children's health problems.     

Probable secondary infections in households of SARS patients in Hong Kong

Although severe acute respiratory syndrome (SARS) is highly infectious in clinical settings, SARS has not been well examined in household settings. The household and household member attack rates were calculated for 1,214 SARS case-patients and their household members, stratified by two phases of the epidemic. A case-control analysis identified risk factors for secondary infection. Secondary infection occurred in 14.9% (22.1% versus 11% in earlier and later phases) of all households and 8% (11.7% versus 5.9% in the earlier and later phases) of all household members. Healthcare workers' households were less likely to be affected. Risk factors from the multivariate analysis included at-home duration before hospitalization, hospital visitation to the SARS patient (and mask use during the visit), and frequency of close contact. SARS transmission at the household level was not negligible in Hong Kong. Transmission rates may be greatly reduced with precautionary measures taken by household members of SARS patients.     

The impact of mobility on HIV control: a modelling study

Mobility is associated with HIV due to more risky sexual behaviour of mobile groups such as travellers and migrants. Limited participation of such groups may reduce the effectiveness of HIV interventions disproportionally. The established STDSIM model, which simulates transmission and control of HIV and STD, was extended to simulate mobility patterns based on data from Tanzania. We explored the impact of non-participation of mobile groups (travellers and recent migrants) on the effectiveness of two interventions: condom promotion and health education aiming at partner reduction. If mobile groups do not participate, the effectiveness of both interventions could be reduced by 40%. The impact of targeting travellers with a combined HIV campaign is close to that of a general population intervention. In conclusion, it is important to account for possible non-participation of migrants and travellers. If non-participation is substantial, impact of interventions can be greatly improved by actively approaching these people.     

Aggressive active case detection: a malaria control strategy based on the Brazilian model

Since 1996, the Brazilian Ministry of Health has adopted a malaria control strategy known as aggressive active case detection (AACD) in which most or all members of every community are tested and treated for malaria on a monthly basis. The strategy attempts to identify and treat cases of asymptomatic malaria, which, if untreated, continue to transmit the infection. Malaria remains uncontrolled because almost all health care systems in the world rely on passive case detection: the treatment of only symptomatic cases of malaria. Research has shown conclusively that asymptomatic cases exist in any population where malaria transmission is stable and incidence is high: therefore passive case detection simply will not succeed in breaking the cycle of transmission. Numerous case studies show that malaria has been successfully controlled on a regional or national level by mass blood surveys. AACD is an effective malaria control strategy if used in conjunction with other methods, especially when (1) an effective treatment exists, (2) influx of potential carriers of the infection can be monitored, and (3) people are inclined to cooperate with monthly blood testing. AACD requires access to rapid diagnostic tests (RDTs), microscopy supplies, extensive human resources, and prompt, affordable, and effective treatment. AACD is compared to PCD in terms of clinical efficacy and cost effectiveness in a case study of malaria in the Brazilian Yanomami Indians. Where it is feasible, AACD could drastically reduce the incidence of malaria and should be an integral part of the World Health Organization's Roll Back Malaria strategy.     

简阳市疟疾防治措施与效果研究

[目的]总结简阳市疟疾防治策略、措施和经验,评价防治效果。[方法]将简阳市1950～2006年疟疾发病资料、流行病学调查、媒介调查、防治、监测资料进行全面分析。[结果]1950年简阳市疟疾发病率为104.9/万,通过采取综合性抗疟措施,从1993年至2006年发病率控制在1/万以下,并且所有乡镇发病率均低于5/万。[结论]简阳市已经达到国家卫生部颁布的《基本消灭疟疾标准》,该市57年来的防治策略和综合抗疟措施是有效的。