Malaria Epidemics Research Articles

A Historical Review of Military Medical Strategies for Fighting Infectious Diseases: From Battlefields to Global Health.

The environmental conditions generated by war and characterized by poverty, undernutrition, stress, difficult access to safe water and food as well as lack of environmental and personal hygiene favor the spread of many infectious diseases. Epidemic typhus, plague, malaria, cholera, typhoid fever, hepatitis, tetanus, and smallpox have nearly constantly accompanied wars, frequently deeply conditioning the outcome of battles/wars more than weapons and military strategy. At the end of the nineteenth century, with the birth of bacteriology, military medical researchers in Germany, the United Kingdom, and France were active in discovering the etiological agents of some diseases and in developing preventive vaccines. Emil von Behring, Ronald Ross and Charles Laveran, who were or served as military physicians, won the first, the second, and the seventh Nobel Prize for Physiology or Medicine for discovering passive anti-diphtheria/tetanus immunotherapy and for identifying mosquito Anopheline as a malaria vector and plasmodium as its etiological agent, respectively. Meanwhile, Major Walter Reed in the United States of America discovered the mosquito vector of yellow fever, thus paving the way for its prevention by vector control. In this work, the military relevance of some vaccine-preventable and non-vaccine-preventable infectious diseases, as well as of biological weapons, and the military contributions to their control will be described. Currently, the civil–military medical collaboration is getting closer and becoming interdependent, from research and development for the prevention of infectious diseases to disasters and emergencies management, as recently demonstrated in Ebola and Zika outbreaks and the COVID-19 pandemic, even with the high biocontainment aeromedical evacuation, in a sort of global health diplomacy.

Historical Malaria Epidemics on Previously Non-Endemic Indo-Pacific Islands.

Islands without prior malaria have on occasion had severe epidemics after its initial introduction, the most infamous example being the Indian Ocean island of Mauritius in 1867. The historical record was examined to see if additional examples of malaria epidemics on Indo-Pacific islands, which were originally non-malarious had been documented. The late nineteenth century depopulation of Polynesian outliers such as Ontong Java has largely been blamed on malaria. Similar but less well-documented instances exist with both the Western Islands, Papua New Guinea, and Rennell in the Solomon Islands. Specific instances of malaria introduction to Grand Comoros and Aldabra Island in the Seychelles occurred by the early twentieth century. In some cases, the epidemics were caused by changes in anopheline vectors while in others new human populations carrying parasites were the important ecological change. It is, however, remarkable how rarely major malaria epidemics have occurred on Indo-Pacific islands.

Epidemic situation of malaria and change trend in Belt and Road countries

Objective: To understand the epidemic situation of malaria and its change trend in the Belt and Road countries. Methods: The 145 countries with which China has signed cooperation documents on the Belt and Road Initiative were selected for this study, and their malaria incidence data were collected from the Global Burden of Disease 2019. The age-standardized incidence rate (ASR) was used to describe the epidemic situation of malaria in 2019. The estimated annual percentage change (EAPC) of the ASR was calculated to assess the incidence trend of malaria from 2013 to 2019. Results: Among the 145 countries, 74 (51.03%) countries had malaria epidemics, mainly in Africa (60.81%, 45/74) and Asia (22.97%, 17/74). The countries with malaria incidence of ≥10 000 per 100 000 in 2019 were mainly distributed in Africa (96.15%, 25/26). From 2013 to 2019, the incidence rates of malaria showed decreasing trends in 32 countries (43.24%), and the incidence rates of malaria in 23 countries (31.08%) showed no significant change, while the incidence rates of malaria in 19 countries (25.68%) showed increasing trends. The obvious increasing trends were observed in Cape Verde (EAPC=151.46, 95%CI: 47.15-329.71), South Africa (EAPC=98.61, 95%CI: 32.11-198.58) and Namibia (EAPC=78.03, 95%CI: 54.30-105.42). Conclusion: About half of the Belt and Road countries had malaria epidemics in 2019, in which 1/4 had increased incidence of malaria. China should continue to strengthen the prevention and control of malaria, especially imported malaria, to maintain the achievements of malaria elimination.

Malaria epidemics detection and associated climatic factors in the Hauts Bassins Health Region of Burkina Faso

Background: Malaria is endemic in the Hauts Bassins Health Region, making it necessary to detect epidemics. Though malaria is a climatic sensitive disease, the association between malaria occurrence and climate is not well known in the Hauts Bassins Health Region. The study sought to detect malaria epidemics and assess the correlation of malaria cases with climate. Methods: A secondary analysis of ecological data from the National Health Information System (NHIS) and the General Directorate of Meteorology of Burkina Faso was conducted. Mean, quartiles and cumulative sum methods were performed to set epidemic thresholds. Correlation between malaria and climatic factors in the health region was assessed using Spearman's test. A Mann-Whitney test determined the association of malaria transmission seasons with climatic variables, at 5%. Kruskal-Wallis test evaluated the relationship between malaria and the years of the occurrence, at a 5% significance level. Results: From 2013 to 2016, 2,521,789 malaria cases were reported in the region, with a mean incidence of 269 cases per 10,000 people. The annual incidence increased from 2,048 cases per 10,000 people in 2013 to 5,277 cases per 10,000 people in 2016. Regardless of the method used, cases were high in 2016, with few exceptions. There was a weak negative correlation between malaria and minimum (r=-0,292; p-value=0.044) and maximum (r=-0,391; p-value=0.006) temperatures. The relationship between relative humidity and malaria was positive and weak (r=0,304; p-value=0.036). Lowest temperatures and highest relative humidity simultaneously drove malaria within-year variability during the high transmission season. Conclusion: Malaria incidence increased unexpectedly in 2016. Malaria endemicity hides a within-year and year-to-year variability, partially driven by the temperature, relative humidity and rainfall.

Cloud-based applications for accessing satellite Earth observations to support malaria early warning

Malaria epidemics can be triggered by fluctuations in temperature and precipitation that influence vector mosquitoes and the malaria parasite. Identifying and monitoring environmental risk factors can thus provide early warning of future outbreaks. Satellite Earth observations provide relevant measurements, but obtaining these data requires substantial expertise, computational resources, and internet bandwidth. To support malaria forecasting in Ethiopia, we developed software for Retrieving Environmental Analytics for Climate and Health (REACH). REACH is a cloud-based application for accessing data on land surface temperature, spectral indices, and precipitation using the Google Earth Engine (GEE) platform. REACH can be implemented using the GEE code editor and JavaScript API, as a standalone web app, or as package with the Python API. Users provide a date range and data for 852 districts in Ethiopia are automatically summarized and downloaded as tables. REACH was successfully used in Ethiopia to support a pilot malaria early warning project in the Amhara region. The software can be extended to new locations and modified to access other environmental datasets through GEE.

Epidemic malaria dynamics in Ethiopia: the role of self-limiting, poverty, HIV, climate change and human population growth

BackgroundDuring the last two decades, researchers have suggested that the changes of malaria cases in African highlands were driven by climate change. Recently, a study claimed that the malaria cases (Plasmodium falciparum) in Oromia (Ethiopia) were related to minimum temperature. Critics highlighted that other variables could be involved in the dynamics of the malaria. The literature mentions that beyond climate change, trends in malaria cases could be involved with HIV, human population size, poverty, investments in health control programmes, among others.MethodsPopulation ecologists have developed a simple framework, which helps to explore the contributions of endogenous (density-dependent) and exogenous processes on population dynamics. Both processes may operate to determine the dynamic behaviour of a particular population through time. Briefly, density-dependent (endogenous process) occurs when the per capita population growth rate (R) is determined by the previous population size. An exogenous process occurs when some variable affects another but is not affected by the changes it causes. This study explores the dynamics of malaria cases (Plasmodium falciparum and Plasmodium vivax) in Oromia region in Ethiopia and explores the interaction between minimum temperature, HIV, poverty, human population size and social instability.ResultsThe results support that malaria dynamics showed signs of a negative endogenous process between R and malaria infectious class, and a weak evidence to support the climate change hypothesis.ConclusionPoverty, HIV, population size could interact to force malaria models parameters explaining the dynamics malaria observed at Ethiopia from 1985 to 2007.

Tuberculosis, HIV/AIDS and Malaria Health Services in sub-Saharan Africa – A Situation Analysis of the Disruptions and Impact of the COVID-19 Pandemic

BackgroundThe unprecedented and ongoing COVID-19 pandemic has exposed weaknesses in African countries’ health systems. The impact of shifted focus on COVID-19 for the past 2 years on routine health services, especially those for the epidemics of Tuberculosis, HIV/AIDS and Malaria, have been dramatic in both quantity and quality. MethodsIn this article, we reflect on the COVID-19 related disruptions on the Tuberculosis, HIV/AIDS and Malaria routine health services across Africa. ResultsThe COVID-19 pandemic resulted in disruptions of routine health services and diversion of already limited available resources in sub-Saharan Africa. As a result, disease programs like TB, malaria and HIV have recorded gaps in prevention and treatment with the prospects of reversing gains made towards meeting global targets. The extent of the disruption is yet to be fully quantified at country level as most data available is from modelling estimates before and during the pandemic. ConclusionsAccurate country-level data is required to convince donors and governments to invest more into revamping these health services and help prepare for managing future pandemics without disruption of routine services. Increasing government expenditure on health is a critical part of Africa's economic policy. Strengthening health systems at various levels to overcome the negative impacts of COVID-19, and preparing for future epidemics will require strong visionary political leadership. Innovations in service delivery and technological adaptations are required as countries aim to limit disruptions to routine services.

Geo-Climatic Factors of Malaria Morbidity in the Democratic Republic of Congo from 2001 to 2019.

Background: Environmentally related morbidity and mortality still remain high worldwide, although they have decreased significantly in recent decades. This study aims to forecast malaria epidemics taking into account climatic and spatio-temporal variations and therefore identify geo-climatic factors predictive of malaria prevalence from 2001 to 2019 in the Democratic Republic of Congo. Methods: This is a retrospective longitudinal ecological study. The database of the Directorate of Epidemiological Surveillance including all malaria cases registered in the surveillance system based on positive blood test results, either by microscopy or by a rapid diagnostic test for malaria was used to estimate malaria morbidity and mortality by province of the DRC from 2001 to 2019. The impact of climatic factors on malaria morbidity was modeled using the Generalized Poisson Regression, a predictive model with the dependent variable Y the count of the number of occurrences of malaria cases during a period of time adjusting for risk factors. Results: Our results show that the average prevalence rate of malaria in the last 19 years is 13,246 (1,178,383–1,417,483) cases per 100,000 people at risk. This prevalence increases significantly during the whole study period (p < 0.0001). The year 2002 was the most morbid with 2,913,799 (120,9451–3,830,456) cases per 100,000 persons at risk. Adjusting for other factors, a one-day in rainfall resulted in a 7% statistically significant increase in malaria cases (p < 0.0001). Malaria morbidity was also significantly associated with geographic location (western, central and northeastern region of the country), total evaporation under shelter, maximum daily temperature at a two-meter altitude and malaria morbidity (p < 0.0001). Conclusions: In this study, we have established the association between malaria morbidity and geo-climatic predictors such as geographical location, total evaporation under shelter and maximum daily temperature at a two-meter altitude. We show that the average number of malaria cases increased positively as a function of the average number of rainy days, the total quantity of rainfall and the average daily temperature. These findings are important building blocks to help the government of DRC to set up a warning system integrating the monitoring of rainfall and temperature trends and the early detection of anomalies in weather patterns in order to forecast potential large malaria morbidity events.

Ethnic conflict as a risk amplifier for resurgent P. vivax malaria in temperate zones: A case study from the Caucasus region

One of the most protracted post-Soviet conflicts of the 1990s was a territorial dispute between Armenia and Azerbaijan over the contested Karabakh region. Years of ethnic violence led to the displacement of nearly a million refugees, as well as a public health crisis that included epidemics of malaria, diphtheria and other preventable diseases. Malaria is not usually considered a health risk in temperate climates, but seasonal epidemics were widespread throughout the Caucasus in the early decades of the twentieth century. This paper combines qualitative historical research with geospatial analysis to explore how endemic malaria was controlled during the Soviet era, and how ethnic conflict reconfigured local ecologies to facilitate the re-emergence of P. vivax after the Soviet collapse in the 1990s. This research reveals that ethnic conflicts have specific qualities that increase risks of infectious and vector borne disease outbreaks, even in places that have successfully achieved a modern health and mortality profile. The risk amplifiers of ethnic conflicts include 1) the creation of contested spaces controlled by separatists that are outside of any national public health surveillance system; 2) mass population movements and refugee outflows due to ethnic violence; and 3) changes in land use that expand potential mosquito breeding sites throughout the conflict zone. Continued hostilities between Armenia and Azerbaijan, combined with the repopulation of key vector species (specifically An. sacharovi) lead us to conclude that populations in the Caucasus remain vulnerable to resurgent outbreaks of ethno-nationalist violence as well as the return of seasonal malaria, even after decades of successful control.

The neglected role of relative humidity in the interannual variability of urban malaria in Indian cities

The rapid pace of urbanization makes it imperative that we better understand the influence of climate forcing on urban malaria transmission. Despite extensive study of temperature effects in vector-borne infections in general, consideration of relative humidity remains limited. With process-based dynamical models informed by almost two decades of monthly surveillance data, we address the role of relative humidity in the interannual variability of epidemic malaria in two semi-arid cities of India. We show a strong and significant effect of humidity during the pre-transmission season on malaria burden in coastal Surat and more arid inland Ahmedabad. Simulations of the climate-driven transmission model with the MLE (Maximum Likelihood Estimates) of the parameters retrospectively capture the observed variability of disease incidence, and also prospectively predict that of ‘out-of-fit’ cases in more recent years, with high accuracy. Our findings indicate that relative humidity is a critical factor in the spread of urban malaria and potentially other vector-borne epidemics, and that climate change and lack of hydrological planning in cities might jeopardize malaria elimination efforts.

The empirical support for the radical cure strategy for eliminating Plasmodium vivax in China

BackgroundWith the recent certification by World Health Organization that the People’s Republic of China is malaria-free, it is timely to consider how elimination of malaria was completed in People’s Republic of China over the last 7 decades. Of the four widespread species of human malaria, Plasmodium vivax was the last to be eliminated by the national program of China. Understanding the incubation periods and relapses patterns of P. vivax through historical data from China is relevant for planning disease elimination in other malaria-endemic countries, with residual P. vivax malaria.MethodsWe collated data from both published and unpublished malaria parasite inoculation experiments conducted between 1979 and 1988 with parasites from different regions of the People’s Republic of China. The studies had at least two years of follow-up. We categorized P. vivax incubation patterns via cluster analysis and investigated relapse studies by adapting a published within-host relapse model for P. vivax temperate phenotypes. Each model was fitted using the expectation-maximization (EM) algorithm initialized by hierarchical model-based agglomerative clustering.ResultsP. vivax parasites from the seven studies of five southern and central provinces in the People’s Republic of China covering geographies ranging from the south temperate to north tropical zones. The parasites belonged to two distinct phenotypes: short- (10–19 days) or long-incubation (228–371 days). The larger the sporozoite inoculation, the more likely short incubation periods were observed, and with more subsequent relapses (Spearman’s rank correlation between the number of inoculated sporozoites and the number of relapses of 0.51, p-value = 0.0043). The median of the posterior distribution for the duration of the first relapse interval after primary infection was 168.5 days (2.5% quantile: 89.7; 97.5% quantile: 227.69 days). The predicted survival proportions from the within-host model fit well to the original relapse data. The within-host model also captures the hypnozoite activation rates and relapse frequencies, which consequently influences the transmission possibility of P. vivax.ConclusionsThrough a within-host model, we demonstrate the importance of clearance of hypnozoites. A strategy of two rounds of radical hypnozoite clearance via mass drug administration (MDA) deployed during transmission (summer and autumn) and non-transmission (late spring) seasons had a pronounced effect on outbreaks during the malaria epidemics in China. This understanding can inform malaria control strategies in other endemic countries with similar settings.

Mining-Associated Malaria Epidemics.

Tropical alluvial gold and gem miners are often an especially at-risk population for malaria infection. Geographical areas of mining-associated malaria epidemics in the recent past include Southeast Asia (Cambodia, Thailand, and Myanmar); the Amazon basin (Brazil, French Guyana, Suriname, Columbia, and Peru); and tropical Africa. Mobile populations of young adult men engaged in the hard labor of mining may experience severe malaria especially if they lack preexisting immunity and are irregularly consuming antimalarial drugs. Particular problems occur because much of this informal mining activity is illegal and done in isolated areas without access to health services and with evidence of emerging antimalarial drug resistance. Concentrating vulnerable populations in an ecologically disturbed landscape is often conducive to epidemics, which can then spread as these highly mobile workers return to their homes. Mining-associated malaria endangers malaria elimination efforts and miners need to be addressed as a group of particular concern.

One Health approach to improve the malaria elimination programme in Henan Province.

One Health is a collaborative, multi-sectoral, trans-disciplinary approach with the goal of achieving optimal health outcomes by recognizing the interconnection between people, animals, plants, and the environment and determining how this relates to the control of infectious diseases such as malaria, schistosomiasis and so on. Malarias caused by Plasmodium that commonly infects female Anopheles mosquitoes, which feed on human blood and act as a disease vector. It has been a worldwide important public health problem from ancient times. Also, malaria is one of the infectious diseases with the longest epidemic time and the most serious harm in the history of Henan Province, China. During the past decades, the multi-sectoral, cross-regional, and multi-disciplinary One Health approach contributed to a significant reduction in malaria incidence, resulting in initiation of the Henan Malaria Elimination Action Plan. Herein, we reviewed the history of the fight against malaria in Henan Province. A full picture of malaria epidemics, prevention, and control strategies were showed, with the objective that it will help stakeholders, and policy-makers to take informed decisions on public health issues and intervention designs on malaria control towards elimination in the similar areas.

Malaria epidemics in Colombia, 1970-2019.

ABSTRACTBackground: Malaria has unstable transmission in Colombia and has variable endemic-epidemic patterns. This study describes the epidemiological characteristics of malaria epidemics registered in Colombia from 1970-2019. Methods: Data from 1979-2019 were collected from the National Public Health Surveillance System. The data was tabulated and pertinent descriptive analyses were carried out. Results: Fifteen malaria outbreaks and approximately five-year-long epidemic cycles were observed in Colombia during the study period. Conclusions: Malaria epidemics in Colombia present a five-yearly transmission pattern, mainly due to the increased vulnerability produced by seasonal population migrations in receptive areas with active transmission.

Surveillance and response systems driving malaria elimination in the mountain areas of Hainan Province.

Hainan Province is in a tropical area of China and previously experienced serious P. falciparum and P. vivax malaria epidemics. After nearly 70 consecutive years of malaria prevention and control, malaria in Hainan has gradually been eliminated. To achieve the elimination of malaria, Hainan enacted six stages: investigative research and pilot prevention and control, large-scale antimalaria measures, adjustment of strategies for prevention and control, joint prevention and control measures, global funding of routine malaria control, and malaria elimination. Different strategies for malaria control were adopted at different stages. Malaria was most prevalent in the mountainous areas of central and southern Hainan, which contain a high-risk population (the forest goers) and two highly effective malaria vectors (An. dirus and An. minimus). Forest goers have been a high-risk population for malaria in Hainan since their identification in the 1990s. This paper summarizes malaria monitoring in forest goers and the response of forest goers to malaria control and elimination, distilling specific malaria control and elimination measures via case studies in Hainan Province. Two case studies in the malaria control stage demonstrated different measures for outbreaks and sporadic cases in forest goers. In view of the malaria outbreak in Sanya during the elimination stage, three-layered strategies (TLSs) were implemented to control outbreaks and improve control measures. Moreover, this paper also illustrates specific management measures to prevent malaria retransmission from sporadic imported malaria cases during the elimination phase. Hainan finally eliminated malaria in 2020. However, the risk of malaria retransmission is still high due to the prevalence of effective malaria vectors in Hainan, and forest goers are still a high-risk population for malaria retransmission.

INTRIGUING PREDICTORS ASSOCIATED WITH MALARIA INFECTION AMONG PREGNANT WOMEN IN MT. ELGON SUB COUNTY, KENYA

Introduction: Universally, malaria continues to ravage the lives of innocent expectant women. In Kenya malaria prevalence among adult females is 28% while in Mt. Elgon Sub County, which is categorised under highland epidemic prone malaria area, prevalence of malaria in pregnancy (MiP) is uncertain. Therefore, this study sought to determine intriguing predictors associated with malaria infection among pregnant women in Mt. Elgon Sub-County.&#x0D; Methods: Cross-sectional analytical design was employed and mixed methods used for data collection. For quantitative data collection, semi-structured questionnaire was used to collect primary data from pregnant women who attended ANC in selected health facilities in the study area. Further, qualitative approach adopted interview guides that targeted key informants in the health facilities. Systematic random sampling method was used to select 392 participants for the study. Data was analysed by SPSS version 25.0. Bivariate logistic regression analysis was used to test the association between independent variable and dependent variable.&#x0D; Findings: Study results revealed that, the prevalence of MiP was 16.2%. Prevalence was higher among women aged less than 25 (67.3%, n=262) compared to those aged &gt; 25 years (33.7%, n=137). The following five factors were statistically significantly associated with malaria prevalence in pregnancy: place of residence (OR: 5.7; 95%CI: 2.6 – 12.4; p &lt; 0.0001); those who tested positive in the last 2 years (OR: 1.7; 95%CI: 1.0 – 2.9; p = 0.05); preferred shape of ITN’s (OR: 3.8; 95%CI: 1.5 – 9.7; p = 0.008);earth floor (OR: 1.8; 95%CI: 1.0 – 3.1; p = 0.03); mud wall (OR: 1.8; 95%CI: 1.0 – 3.1; p = 0.03). In conclusion, age group, place of residence, testing positive in the last 2 years, preferred shape of ITN, earth floor and mud wall were significant factors associated with MiP.&#x0D; Recommendations: To curb MiP, the study recommends Bungoma County government to promote use of ITNs and preferable rectangular ITN’s by ensuring they are translated to appropriate use; support regular indoor residual spraying with insecticides and educate the residents on the role of improved housing on malaria protection and empowerment of the community to adopt improved housing.

Callus Culture as an Alternative Source of Secondary Metabolites in Curtailing Malaria Epidemic

Malaria remains a threat to public healthcare system. In 2018, more than 200 million people were exposed to this disease globally. There have been reports of drug-resistance in the recommended therapy in some endemic regions. This called for relentless efforts in the search for potential antimalarial compounds.&#x0D; An in vitro culture technique has emerged as a promising option for sustainable and industrial propagation of plant bioactive compounds with wide range of medicinal properties. The demand for these invaluable metabolites is witnessing a continuous increase as a folk medicine, hence, endangering their existence in natural habitats. Besides its use in natural form, the nature’s gift to humans seems to be restricted and limited by environmental conditions. An in vitro culture approach remains the most viable and sustainable alternative for the endangered plant species. Here, we present some plant species reported to have potential antimalarial activities and recommend further study through callus culture induction against malaria.

Conquering COVID: How Global Vaccine Inequality Risks Prolonging the Pandemic.

The development of effective vaccines during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been deemed a towering achievement in modern science. Since the end of 2020, the vaccine rollout has offered the promise of vanquishing the pandemic in the United States and other developed countries. Even as the United States and other wealthier nations encounter both setbacks and successes in their coronavirus disease 2019 (COVID-19) eradication efforts, developing countries around the world are likely to face far less fortunate fates. With much of the world’s vaccine production and distribution capacity reserved by wealthier nations, impoverished countries stand to face devastating financial, social, and health-related impacts. The consequences of this disparity will resonate deeply into the collective fabric of these countries, ensuring that the economic and geopolitical imbalance between developed and developing nations will widen even more substantially. Wealthier countries must do more to eliminate the inequality that exists in widespread SARS-CoV-2 vaccine availability in less-developed nations. Like HIV, tuberculosis, malaria, and other global epidemics, COVID-19 cannot be forgotten just because the pandemic is eventually contained from the shores of wealthier nations. For as long as the pandemic rages in any corner of the globe, the world will never be truly rid of COVID-19. And all nations, rich or poor, will suffer the consequences.

Dihydroartemisinin-Piperaquine Chemoprevention and Malaria Incidence After Severe Flooding: Evaluation of a Pragmatic Intervention in Rural Uganda

Malaria epidemics are a well-described phenomenon after extreme precipitation and flooding. Yet, few studies have examined mitigation measures to prevent post-flood malaria epidemics. We evaluated a malaria chemoprevention program implemented in response to severe flooding in western Uganda. Children aged ≤12 years from 1 village were eligible to receive 3 monthly rounds of dihydroartemisinin-piperaquine (DP). Two neighboring villages served as controls. Malaria cases were defined as individuals with a positive rapid diagnostic test result as recorded in health center registers. We performed a difference-in-differences analysis to estimate changes in the incidence and test positivity of malaria between intervention and control villages. A total of 554 children received at least 1 round of chemoprevention, with 75% participating in at least 2 rounds. Compared with control villages, we estimated a 53.4% reduction (adjusted rate ratio [aRR], 0.47; 95% confidence interval [CI]: .34-.62; P < .01) in malaria incidence and a 30% decrease in the test positivity rate (aRR, 0.70; 95% CI: .50-.97; P = .03) in the intervention village in the 6 months post-intervention. The impact was greatest among children who received the intervention, but decreased incidence was also observed in older children and adults (aRR, 0.57; 95% CI: .38-.84; P < .01). Three rounds of chemoprevention with DP delivered under pragmatic conditions reduced the incidence of malaria after severe flooding in western Uganda. These findings provide a proof-of-concept for the use of malaria chemoprevention to reduce excess disease burden associated with severe flooding.

Synthesis of novel 1,2,4-trioxanes and antimalarial evaluation against multidrug-resistant Plasmodium yoelii nigeriensis

Malaria epidemics represent one of the life-threatening diseases to low-income lying countries which subsequently affect the economic and social condition of mankind. In continuation in the development of a novel series of 1,2,4-trioxanes 13a1-c1, 13a2-c2, and 13a3-c3 have been prepared and further converted into their hemisuccinate derivatives 14a1-c1, 14a2-c2, and 14a3-c3 respectively. All these new compounds were evaluated for their antimalarial activity against multidrug-resistant Plasmodium yoelii nigeriensis in mice by both oral and intramuscular (im) routes. Hydroxy-functionalized trioxane 13a1 showed 80% protection and its hemisuccinate derivative 14a1 showed 100% protection at a dose of 48 mg/kg × 4 days by both routes, which is twice active than artemisinin by oral route.