Reduction In Malaria Cases Research Articles

Emerging public health strategies in malaria control: innovations and implications.

Malaria remains a significant global health challenge, particularly in regions with limited resources and tropical climates. Despite extensive efforts, the disease continues to cause significant morbidity and mortality, with ~229 million cases and 409000 deaths reported in 2020. However, recent years have seen promising advancements in public health strategies aimed at malaria control and elimination. Technological advancements have played a crucial role in improving malaria control efforts. Genomic surveillance techniques enable the monitoring of malaria parasite populations, aiding in the detection of drug resistance and informing targeted interventions. Additionally, innovative diagnostic technologies, such as rapid diagnostic tests (RDTs) and molecular assays, have enhanced the speed and accuracy of malaria diagnosis, facilitated prompt treatment and reduced transmission. These tools are instrumental in achieving the WHO goals of reducing malaria cases and deaths by at least 90% by 2030. Novel vector control methods offer innovative approaches to reduce malaria transmission. Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) remain foundational strategies, with advancements including the development of next-generation insecticides and long-lasting insecticidal nets (LLINs). Furthermore, genetic modification of mosquitoes, such as gene drive technology, holds promise for reducing mosquito populations and interrupting malaria transmission. These vector control innovations complement other strategies, contributing to comprehensive malaria control efforts aimed at achieving sustainable disease reduction and eventual elimination.

The monthly trends of malaria cases in children under 5 years of age in Guinea: comparative analysis between a seasonal malaria chemoprevention (SMC) and a non-SMC health district

BackgroundThe Republic of Guinea, where malaria represents the leading cause of morbidity and mortality among children, the seasonal malaria chemoprevention (SMC) is deployed only in areas with very seasonal modes of transmission. It should target children at the highest risk of serious illness. The objective of the study was to prevent uncomplicated and serious cases of malaria in the target population. This study aimed to analyse the monthly trends in malaria-related morbidity among children under the age of 5 in Guinea.MethodsThis was a quasi-experimental study with routine data from the National Health Information System (SNIS). The two districts Mamou (the SMC intervention site) and Kindia (the control site) were selected to compare the monthly trends in malaria cases among children under the age of 5, from July to October, covering the years from 2015 to 2020. The statistical analysis used interrupted time series to estimate the effects of the SMC.ResultsThe SMC programme contributed to a significant average reduction in the number of malaria cases of 225 cases per month in the intervention district (95% CI − 362 to − 88; p = 0.002), compared to the control district. However, the study also revealed that the effect of SMC varied between cycles, presenting different monthly malaria cases.ConclusionThe SMC contributed to a significant reduction in malaria cases among children under the age of 5 in the health district of Mamou from 2018 to 2020. However, this reduction varied by monthly SMC cycle. This study suggests extending the SMC in other areas with high perennial seasonal transmission respecting the World Health Organization SMC eligibility criteria, as a strategy in the dynamic of reducing malaria cases in children under the age of 5 in Guinea.

Genomic surveillance of malaria parasites in an indigenous community in the Peruvian Amazon

Hard-to-reach communities represent Peru's main challenge for malaria elimination, but information about transmission in these areas is scarce. Here, we assessed Plasmodium vivax (Pv) and P. falciparum (Pf) transmission dynamics, resistance markers, and Pf hrp2/3 deletions in Nueva Jerusalén (NJ), a remote, indigenous community in the Peruvian Amazon with high population mobility. We collected samples from November 2019 to May 2020 by active (ACD) and passive case detection (PCD) in NJ. Parasites were identified with microscopy and PCR. Then, we analyzed a representative set of positive-PCR samples (Pv = 68, Pf = 58) using highly-multiplexed deep sequencing assays (AmpliSeq) and compared NJ parasites with ones from other remote Peruvian areas using population genetics indexes. The ACD intervention did not reduce malaria cases in the short term, and persistent malaria transmission was observed (at least one Pv infection was detected in 96% of the study days). In Nueva Jerusalen, the Pv population had modest genetic diversity (He = 0.27). Pf population had lower diversity (He = 0.08) and presented temporal clustering, one of these clusters linked to an outbreak in February 2020. Moreover, Pv and Pf parasites from NJ exhibited variable levels of differentiation (Pv Fst = 0.07–0.52 and Pf Fst = 0.11–0.58) with parasites from other remote areas. No artemisin resistance mutations but chloroquine (57%) and sulfadoxine-pyrimethamine (35–67%) were detected in NJ's Pf parasites. Moreover, pfhrp2/3 gene deletions were common (32–50% of parasites with one or both genes deleted). The persistent Pv transmission and the detection of a Pf outbreak with parasites genetically distinct from the local ones highlight the need for tailored interventions focusing on mobility patterns and imported infections in remote areas to eliminate malaria in the Peruvian Amazon.

Efficacy of Interceptor G2, Royal Guard and PermaNet 3.0 against pyrethroid-resistant Anopheles gambiae s.l. from Za-Kpota, southern Benin: an experimental hut trial

BackgroundThe widespread use of insecticide-treated nets (ITNs) has significantly contributed to the reduction in malaria cases and deaths observed across Africa. Unfortunately, this control strategy is threatened by the rapid spread of pyrethroid resistance in malaria vectors. Dual-active-ingredient insecticidal nets are now available to mitigate the impact of pyrethroid resistance. To facilitate evidence-based decisions regarding product selection in specific use settings, data are needed on the efficacy of these different nets against local mosquito populations.MethodsTwo experimental hut trials were performed in Za-Kpota, southern Benin in 2021 to evaluate the performance of Interceptor G2 (BASF), Royal Guard (Disease Control Technologies) and PermaNet 3.0 (Vestergaard Frandsen), all dual-active-ingredient bednets, in comparison to untreated or standard pyrethroid-treated bednets, against free-flying wild Anopheles gambiae mosquitoes. The performance of some of these next-generation nets was compared to the same type of nets that have been in use for up to 2 years. Mosquitoes collected in the huts were followed up after exposure to assess the sublethal effects of treatments on certain life-history traits.ResultsThe predominant species in the study site was Anopheles gambiae sensu stricto (An. gambiae s.s.). Both Anopheles coluzzii and An. gambiae s.s. were resistant to pyrethroids (deltamethrin susceptibility was restored by piperonyl butoxide pre-exposure). In the experimental hut trials, the highest blood-feeding inhibition (5.56%) was recorded for the Royal Guard net, relative to the standard PermaNet 2.0 net (44.44% inhibition). The highest 72-h mortality rate (90.11%) was recorded for the Interceptor G2 net compared to the PermaNet 2.0 net (56.04%). After exposure, the risk of death of An. gambiae sensu lato (An. gambiae s.l.) was 6.5-fold higher with the Interceptor G2 net and 4.4-fold higher with the PermaNet 3.0 net compared to the respective untreated net. Lower mosquito mortality was recorded with an aged Interceptor G2 net compared to a new Interceptor G2 net. Oviposition rates were lower in mosquitoes collected from huts containing ITNs compared to those of untreated controls. None of the mosquitoes collected from huts equipped with Royal Guard nets laid any eggs.ConclusionsThe Royal Guard and Interceptor G2 nets showed a potential to significantly improve the control of malaria-transmitting vectors. However, the PermaNet 3.0 net remains effective in pyrethroid-resistant areas.Graphical

Evaluation of Outbreak Preparedness to Prevent the Reintroduction of Malaria in Ramanagara District: A Descriptive Epidemiological Study.

Background Malaria is a vector-borne disease transmitted by female anopheline mosquitoes. It is also a multidimensional disease influenced by social factors such as poor environmental conditions and awareness gaps. India has witnessed a substantial reduction in malaria cases and has declared three regions as malaria-free, with Karnataka being one of the states. However, Karnataka witnesses significant population movement and migration, which influences the spread of malaria. Ramanagara, a district in Karnataka, reported zero indigenous cases over the past three years. Hence, we selected this district to evaluate outbreak preparedness to prevent the reintroduction of malaria. This choice underscores the district's significance as a valuable model for preventing the reintroduction of malaria. Methodology Baseline survey data on malaria cases and vector survey data were evaluated for the period spanning 2018 to 2022. The data were gathered from both the regional office and the Ramanagara district health office. In addition to the documenting system, because there was no regular submission of Form-P and Form-L of the Integrated Disease Surveillance Project and Integrated Health Information Platform from the private sector, to complete the missing data, across-sectional study was conducted among private sector practitioners and pharmacies in Ramanagara from April 2023 to June 2023. Data was collected via interviews using a malaria surveillance assessment toolkit sourced from the National Centre for Vector Borne Diseases Control and World Health Organization protocols to assess six core areas of malaria elimination. Data collected via interviews were compiled in MS Excel and analyzed using SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, NY, USA). Results Malaria control measures in the selected district achieved >80% coverage with notable improvements in the National Health Mission-National Vector Borne Disease Control Programme fund utilization, logistics availability, and physical performance over the past five years. The Annual Parasite Index was <1 at 0.0061 in 2018 and 0.0017 in 2022. The annual blood examination rate was consistently >10 from 22.05 in 2018 to 24.36 in 2022. The primary vectors identified were Anopheles culicifacies and Anopheles stephensi. In 2018, there were six cases of Plasmodium vivax and one case of Plasmodium falciparum reported as imported cases. In 2021 and 2022, two cases of P. vivax were reported. Notably, there were no instances of mixed infections or indigenous cases documented from 2018 to 2022 Conclusions Although the level of outbreak preparedness in the region is satisfactory, the effectiveness of vector control measures appears to be lacking. Increased government funding is needed along with comprehensive training and workshops for healthcare workers. Adequate financial resources and enhanced skills among healthcare workers are crucial to reinforce the existing efforts to control vectors and prevent potential outbreaks effectively.

Drivers of autochthonous malaria cases over time: could the Central European present the African future?

BackgroundResults of spatial and temporal comparison of malaria hotspots and coldspots could improve the health measures of malaria control and eradication strategies. The study aimed to reveal the spatially and temporally independent correlations between the potentially most effective background variables and the number of autochthonous malaria cases.MethodsRelationships between malaria cases and background variables were studied in 2 km × 2 km sized quadrates (10 Central European and 10 African). In addition to the current habitat structure of the African sites, annual precipitation, and annual mean temperature, data of the above parameters detected in the nineteenth and twentieth centuries and currently in the Central European sites were included in the analyses (n = 40). Mann–Whitney tests, Principal Component Analysis, and Generalized Linear Models were used for the examinations.ResultsIn addition to the apparent significant positive correlation of malaria cases with annual rainfall and mean temperature, several correlations were found for habitat parameters. The cover of marshlands in the 19th-century habitat structure of Central European quadrates was considerably the same as in the recent African ones. The extent of rural residential areas was significantly smaller in the 19th-century habitat structure of Central European quadrats than in present-day African ones. According to the revealed correlations, the surface cover of rural residential areas is the main driver of the number of autochthonous malaria cases that we can directly impact.ConclusionsThe study confirmed with historical comparison that not only the annual rainfall and mean temperature, the cover of marshlands and other habitats with breeding sites, but also the elements of the rural human environment play a significant role in the high number of autochthonous malaria cases, probably through the concentration and enhancing sites for vector mosquitoes. The latter confirms that a rapid urbanization process could reduce malaria cases in the most infected areas of Africa. Until the latter happens, extensive biological control of Anopheles larvae and chemical control (both outdoor and indoor) of their imagoes, further mosquito nets, repellents, and carbon dioxide traps will need to be applied more widely in the most heavily infested areas.

Insecticide susceptibility status of Anopheles albimanus populations in historical malaria foci in Quintana Roo, Mexico

BackgroundMexico has experienced a significant reduction in malaria cases over the past two decades. Certification of localities as malaria-free areas (MFAs) has been proposed as a steppingstone before elimination is achieved throughout the country. The Mexican state of Quintana Roo is a candidate for MFA certification. Monitoring the status of insecticide susceptibility of major vectors is crucial for MFA certification. This study describes the susceptibility status of Anopheles albimanus, main malaria vector, from historically important malaria foci in Quintana Roo, using both phenotypic and genotypic approaches.MethodsAdult mosquito collections were carried out at three localities: Palmar (Municipality of Othon P. Blanco), Buenavista (Bacalar) and Puerto Morelos (Puerto Morelos). Outdoor human-landing catches were performed by pairs of trained staff from 18:00 to 22:00 during 3-night periods at each locality during the rainy season of 2022. Wild-caught female mosquitoes were exposed to diagnostic doses of deltamethrin, permethrin, malathion, pirimiphos-methyl or bendiocarb using CDC bottle bioassays. Mortality was registered at the diagnostic time and recovery was assessed 24 h after exposure. Molecular analyses targeting the Voltage-Gated Sodium Channel (vgsc) gene and acetylcholinesterase (ace-1) gene were used to screen for target site polymorphisms. An SNP analysis was carried out to identify mutations at position 995 in the vgsc gene and at position 280 in the ace-1 gene.ResultsA total of 2828 anophelines were collected. The main species identified were Anopheles albimanus (82%) and Anopheles vestitipennis (16%). Mortalities in the CDC bottle bioassay ranged from 99% to 100% for all the insecticides and mosquito species. Sequence analysis was performed on 35 An. albimanus across the three localities; of those, 25 were analysed for vgsc and 10 for ace-1 mutations. All individuals showed wild type alleles.ConclusionThe results demonstrated that An. albimanus populations from historical malaria foci in Quintana Roo are susceptible to the main insecticides used by the Ministry of Health.

Insecticide-treated bed nets and residual indoor spraying reduce malaria in areas with low transmission: a reanalysis of the Maltrials study

BackgroundThe malaria incidence data from a malaria prevention study from the Rift Valley, Central Ethiopia, were reanalysed. The objective was to investigate whether including an administrative structure within the society, which may have required consideration in the protocol or previous analysis, would provide divergent outcomes on the effect measures of the interventions.MethodsA cluster-randomized controlled trial lasting 121 weeks with 176 clusters in four groups with 6071 households with 34,548 persons was done: interventions combining indoor residual spraying (IRS) and insecticide-treated nets (ITNs), IRS alone, ITNs alone and routine use. The primary outcome was malaria incidence. A multilevel negative binomial regression model was employed to examine the impact of the kebele (smallest administrative unit) and the proximity of homes to the primary mosquito breeding sites as potential residual confounders (levels). The study also assessed whether these factors influenced the effect measures of the interventions.ResultsThe study's initial findings revealed 1183 malaria episodes among 1059 persons, with comparable effects observed across the four intervention groups. In the reanalysis, the results showed that both ITN + IRS (incidence rate ratio [IRR] 0.63, P < 0.001) and ITN alone (IRR 0.78, P = 0.011) were associated with a greater reduction in malaria cases compared to IRS (IRR 0.90; P = 0.28) or the control (reference) group. The combined usage of IRS with ITN yields better outcomes compared to the standalone use of ITN and surpasses the effectiveness of IRS in isolation.ConclusionThe findings indicate that implementing a combination of IRS and ITN and also ITN alone decrease malaria incidence. Furthermore, there was an observed synergistic impact when ITN and IRS were used in combination. Considering relevant social structures as potential residual confounders is of paramount importance.Trial registration: PACTR201411000882128 (08 September 2014).

Progress towards malaria elimination in the Greater Mekong Subregion: perspectives from the World Health Organization

Malaria remains a global health challenge, disproportionately affecting vulnerable communities. Despite substantial progress, the emergence of anti-malarial drug resistance poses a constant threat. The Greater Mekong Subregion (GMS), which includes Cambodia, China’s Yunnan province, Lao People's Democratic Republic, Myanmar, Thailand, and Viet Nam has been the epicentre for the emergence of resistance to successive generations of anti-malarial therapies. From the perspective of the World Health Organization (WHO), this article considers the collaborative efforts in the GMS, to contain Plasmodium falciparum artemisinin partial resistance and multi-drug resistance and to advance malaria elimination. The emergence of artemisinin partial resistance in the GMS necessitated urgent action and regional collaboration resulting in the Strategy for Malaria Elimination in the Greater Mekong Subregion (2015–2030), advocating for accelerated malaria elimination interventions tailored to country needs, co-ordinated and supported by the WHO Mekong malaria elimination programme. The strategy has delivered substantial reductions in malaria across all GMS countries, with a 77% reduction in malaria cases and a 97% reduction in malaria deaths across the GMS between 2012 and 2022. Notably, China was certified malaria-free by WHO in 2021. Countries' ownership and accountability have been pivotal, with each GMS country outlining its priorities in strategic and annual work plans. The development of strong networks for anti-malarial drug resistance surveillance and epidemiological surveillance was essential. Harmonization of policies and guidelines enhanced collaboration, ensuring that activities were driven by evidence. Challenges persist, particularly in Myanmar, where security concerns have limited recent progress, though an intensification and acceleration plan aims to regain momentum. Barriers to implementation can slow progress and continuing innovation is needed. Accessing mobile and migrant populations is key to addressing remaining transmission foci, requiring effective cross-border collaboration. In conclusion, the GMS has made significant progress towards malaria elimination, particularly in the east where several countries are close to P. falciparum elimination. New and persisting challenges require sustained efforts and continued close collaboration. The GMS countries have repeatedly risen to every obstacle presented, and now is the time to re-double efforts and achieve the 2030 goal of malaria elimination for the region.

Knowledge enhancement for cadres: Malaria surveillance and vector control in Kaligesing, Purworejo Regency

Purworejo is among the districts with the highest malaria cases in Central Java, reaching 517 cases in 2021 and 544 cases in 2022. Kaligesing District, in particular, recorded the highest number of malaria cases in Purworejo Regency in 2022, with an API of 5.5 per 1000 population. The high incidence of malaria is influenced by various risk factors, including limited public understanding of malaria and community-based surveillance. Additionally, the less-than-optimal control of malaria vectors in the community contributes to this issue. The objective of this service is to reduce malaria cases in Kaligesing District by enhancing the understanding of Village Malaria Cadres and Interpreters (JMD) regarding malaria surveillance and vector control. The method involves providing surveillance assistance and conducting malaria vector control training for cadres and JMD. Results from this program indicate a significant improvement in participants' general knowledge. The paired samples t-test revealed an average score of 58.2% before training and 79.6% after training, with a p-value 0.0001. This demonstrates a substantial difference in participants' knowledge before and after training. Consequently, this activity is deemed successful in enhancing the knowledge of cadres and JMD regarding malaria surveillance and vector control.

The Need for Novel Asexual Blood-Stage Malaria Vaccine Candidates for Plasmodium falciparum.

Extensive control efforts have significantly reduced malaria cases and deaths over the past two decades, but in recent years, coupled with the COVID-19 pandemic, success has stalled. The WHO has urged the implementation of a number of interventions, including vaccines. The modestly effective RTS,S/AS01 pre-erythrocytic vaccine has been recommended by the WHO for use in sub-Saharan Africa against Plasmodium falciparum in children residing in moderate to high malaria transmission regions. A second pre-erythrocytic vaccine, R21/Matrix-M, was also recommended by the WHO on 3 October 2023. However, the paucity and limitations of pre-erythrocytic vaccines highlight the need for asexual blood-stage malaria vaccines that prevent disease caused by blood-stage parasites. Few asexual blood-stage vaccine candidates have reached phase 2 clinical development, and the challenges in terms of their efficacy include antigen polymorphisms and low immunogenicity in humans. This review summarizes the history and progress of asexual blood-stage malaria vaccine development, highlighting the need for novel candidate vaccine antigens/molecules.

In silico prediction and in vitro assessment of novel heterocyclics with antimalarial activity

The development of new antimalarials is paramount to keep the goals on reduction of malaria cases in endemic regions. The search for quality hits has been challenging as many inhibitory molecules may not progress to the next development stage. The aim of this work was to screen an in-house library of heterocyclic compounds (HCUV) for antimalarial activity combining computational predictions and phenotypic techniques to find quality hits. The physicochemical determinants, pharmacokinetic properties (ADME), and drug-likeness of HCUV were evaluated in silico, and compounds were selected for structure-based virtual screening and in vitro analysis. Seven Plasmodium target proteins were selected from the DrugBank Database, and ligands and receptors were processed using UCSF Chimera and Open Babel before being subjected to docking using Autodock Vina and Autodock 4. Growth inhibition of P. falciparum (3D7) cultures was tested by SYBR Green assays, and toxicity was assessed using hemolytic activity tests and the Galleria mellonella in vivo model. From a total of 792 compounds, 341 with good ADME properties, drug-likeness, and no interference structures were subjected to in vitro analysis. Eight compounds showed IC50 ranging from 0.175 to 0.990 µM, and active compounds included pyridyl-diaminopyrimido-diazepines, pyridyl-N-acetyl- and pyridyl-N-phenyl-pyrazoline derivatives. The most potent compound (UV802, IC50 0.178 µM) showed no toxicophoric and was predicted to interact with P. falciparum 1-cysperoxidredoxin (PfPrx1). For the remaining 7 hits (IC50 < 1 μM), 3 showed in silico binding to PfPrx1, one was predicted to bind the haloacid dehalogenase-like hydrolase and plasmepsin II, and one interacted with the plasmodial heat shock protein 90.

Analysis of the socio-economic and cultural factors affecting malaria prevention in provinces with high malaria prevalence in Zambia

Malaria, which is endemic in all the provinces of Zambia, remains one of the leading causes of morbidity and mortality. Records of the high prevalence of malaria is evident in Northern, Eastern, Muchinga and Luapula provinces, despite the implementation of malaria control and prevention strategies aimed at interrupting the disease transmission, which includes the use of treated mosquito nets, indoor residual spraying, presumptive, and treatment therapy among others. These provinces' socio-cultural and economic factors were explored to ascertain if they might contribute to the altered effectiveness of malaria control interventions that have proved successful in other provinces. This study analysed the socio-cultural and economic factors affecting malaria prevention in provinces with high malaria prevalence in Zambia. A descriptive cross-sectional study was conducted. An interviewer-administered questionnaire was administered to selective households in the four study provinces. 1,580 people participated in the study, with a response rate of 98.8%. 684 were male, and 896 were female. Findings suggest practices and beliefs concerning socio-cultural and economic factors influence the success of malaria control interventions in the provinces. Low levels of education and lack of it, directly impacted the understanding of malaria prevention, transmission, and interventions. Self- medication, use of leftover medicines, and seeking treatment late were attributed to low-income levels in all the four provinces. Type of housing and occupation exposed individuals to malaria infection. Tailoring malaria preventive measures to the socio-cultural and economic practices of the provinces will help reduce malaria cases in the provinces.

Global trends in the burden of malaria: Contemporary diagnostic approaches, and treatment strategies

Malaria continues to pose a significant global health challenge, with 247 million cases reported in 2021, primarily concentrated in African countries. Despite substantial progress in reducing malaria cases and deaths over the past two decades, the COVID-19 pandemic disrupted healthcare systems, resulting in a temporary increase in cases and deaths in 2020. Nevertheless, between 2000 and 2021, an estimated 2 billion malaria cases and 11.7 million deaths were averted, with the majority occurring in the WHO African Region. Accurate diagnosis remains pivotal for effective malaria treatment, and various diagnostic methods have been employed, each with its own limitations. The effectiveness of these methods varies across different populations and environments. To combat the resurgence of malaria and the limitations of current interventions, there is a growing need for new technologies and integrated diagnosis and treatment. This paper reviews global trends in the burden of malaria; contemporary diagnostic approaches, and treatment strategies.

Using routine health data to evaluate the impact of indoor residual spraying on malaria transmission in Madagascar

IntroductionIndoor residual spraying (IRS) and insecticide-treated bed nets (ITNs) are cornerstone malaria prevention methods in Madagascar. This retrospective observational study uses routine data to evaluate the impacts of IRS overall,...

Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse

Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.

Synergistic interaction of two antimalarial drugs, artemisinin and concanamycin A

Artemisinin is a powerful drug that has been combined with other antimalarial drugs to combat malaria and it has been crucial to recent achievements in reducing malaria cases. However, the emergence of Plasmodium falciparum resistance against artemisinin has become a serious problem in malaria treatment. Our previous studies reported that artemisinin alkalinised the digestive vacuole of P. falciparum similarly to concanamycin A. Concanamycin A is a specific inhibitor of V-type H+-ATPase, a proton pump located on the membrane of the digestive vacuole. A study also showed that a low concentration of concanamycin A is required to kill 50% of the parasites. Therefore, this study aimed to determine the interaction of artemisinin with concanamycin A by using the isobologram analysis of effects on parasite growth. The antimalarial activity (IC50) of artemisinin and concanamycin A was evaluated by using a malarial SBYR Green I fluorescence-based (MSF) assay prior to isobologram analysis. Based on their IC50 values, six different combination solutions of the drugs were assigned and used in the isobologram analysis. The IC50 of artemisinin and concanamycin A was 13 ± 2.52 nM and 7 ± 1.15 nM, respectively. The interaction of artemisinin and concanamycin A was found to be synergistic, indicating that the combination of these drugs could kill the parasites more effectively. This study suggests that artemisinin and concanamycin A combination can be a new candidate in artemisinin-based combination therapies.

Literatur Review: Plant Efficacy as Biolarvicide for Anopheles Mosquito Vector Control

Mosquito vectors are a severe threat to the prevalence and incidence of malaria, dengue fever, yellow fever, and filariasis. Malaria is a Plasmodium infection that is transmitted by the female Anopheles mosquito. Malaria cases in tropical and subtropical countries have social and economic impacts. Mosquito vector control has been using chemical and synthetic compounds. This method can reduce malaria cases, but it creates new problems that also slow down the elimination of malaria in the long run. Vector control in the larval phase using bioactive compounds of various plants is an alternative to eradicating vectors; besides that, utilizing these bioactive compounds is relatively safer, cheaper, and more accessible. Plants contain several compounds that are toxic to Anopheles mosquito larvae. This literature study summarizes research on extracts of various plants that function as larvicides of the Anopheles mosquito. The research method uses a literature study. The literature related to the research topic was obtained from the databases of Google Scholar, Semantic Sholar, Garuda, PubMed, and Science Direct. The primary literature is a publication of the last ten years. The literature study results showed that the plants Vitex negundo Linn., Lawsonia inermis Linn., Stachys byzantina K.Koch., Pithecellobium dulce Bth., Olax dissiti?ora Oliv., Ipomea cairica Linn., Ricinnus communis Linn., Carica papaya Linn., Paederia foetida Linn., Glycosmis pentaphylla Retz., Terminalia chebula Retz., Annona squamosa Linn., Tagetes erecta Linn. and Azadiracha indica Juss. against mosquito vectors. This study concludes that secondary plant metabolites can be used as candidates and alternatives for controlling Anopheles mosquito larvae.

The effect of the COVID-19 lockdown on malaria transmission in South Africa

BackgroundFor a country such as South Africa which is targeting malaria elimination, mobile and migrant populations pose a substantial risk to importation of malaria parasites. It has been hypothesized that halting cross-border movement of mobile and migrant populations will decrease the importation of malaria, however this option is not a politically, operationally, and financially viable prospect. It has social impacts as well, since families live on either side of the border and preventing travel will challenge family ties. Due to the COVID-19 pandemic and closure of ports of entry (land and air) for non-essential travel into South Africa, a unique opportunity arose to test the hypothesis.MethodologyAn interrupted time series analysis was done to assess whether the post-lockdown trends (April–December 2020) in monthly reported imported and local cases differed from the pre-lockdown trends (January 2015–March 2020). The analysis was conducted separately for KwaZulu-Natal, Mpumalanga, and Limpopo provinces.ResultsOn average, imported cases were lower in the post-intervention period in all three provinces, and local cases were lower in Mpumalanga and Limpopo, though no results were statistically significant.ConclusionSince population movement continued after the travel restrictions were lifted, border screening with testing and treating should be considered for reducing parasite movement. Another option is reducing malaria cases at the source in neighbouring countries by implementing proven, effective vector and parasite control strategies and through a downstream effect reduce malaria entering South Africa.

Evaluation of the model malaria elimination strategy in Mandla district along with its neighbouring districts: a time series analysis from 2008 to 2020

BackgroundCompared to 2017, India achieved a significant reduction in malaria cases in 2020. Madhya Pradesh (MP) is a tribal dominated state of India with history of high malaria burden in some districts. District Mandla of MP state showed a considerable decline in malaria cases between 2000 and 2013, except in 2007. Subsequently, a resurgence of malaria cases was observed during 2014 and 2015. The Malaria Elimination Demonstration Project (MEDP) was launched in 2017 in Mandla with the goal to achieve zero indigenous malaria cases. This project used: (1) active surveillance and case management using T4 (Track fever, Test fever, Treat patient, and Track patient); (2) vector control using indoor residual sprays and long-lasting insecticidal nets; (3) information education communication and behaviour change communication; and (4) regular monitoring and evaluation with an emphasis on operational and management accountability. This study has investigated malaria prevalence trends from 2008 to 2020, and has predicted trends for the next 5 years for Mandla and its bordering districts.MethodsThe malaria prevalence data of the district Mandla for the period of January 2008 to August 2017 was obtained from District Malaria Office (DMO) Mandla and data for the period of September 2017 to December 2020 was taken from MEDP data repository. Further, the malaria prevalence data for the period of January 2008 to December 2020 was collected from DMOs of the neighbouring districts of Mandla. A univariate time series and forecast analysis was performed using seasonal autoregressive integrated moving average model.FindingsMalaria prevalence in Mandla showed a sharp decline [− 87% (95% CI − 90%, − 84%)] from 2017 to 2020. The malaria forecast for Mandla predicts zero cases in the next 5 years (2021–2025), provided current interventions are sustained. By contrast, the model has forecasted a risk of resurgence of malaria in other districts in MP (Balaghat, Dindori, Jabalpur, Seoni, and Kawardha) that were not the part of MEDP.ConclusionThe interventions deployed as part of MEDP have resulted in a sustainable zero indigenous malaria cases in Mandla. Use of similar strategies in neighbouring and other malaria-endemic districts in India could achieve similar results. However, without adding extra cost to the existing intervention, sincere efforts are needed to sustain these interventions and their impact using accountability framework, data transparency, and programme ownership from state to district level.