scholarly journals Plasmodium falciparum genomic surveillance reveals spatial and temporal trends, association of genetic and physical distance, and household clustering

2020 ◽  
Author(s):  
Mouhamad Sy ◽  
Awa Deme ◽  
Joshua L. Warren ◽  
Rachel F. Daniels ◽  
Baba Dieye ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Malaria Control ◽  
Control Strategies ◽  
Temporal Trends ◽  
Genomic Data ◽  
Physical Distance ◽  
Genetic Types ◽  
Molecular Barcode ◽  
Spatial And Temporal Trends ◽  
Identity By State

ABSTRACTMolecular epidemiology using genomic data can help identify relationships between malaria parasite population structure, malaria transmission intensity, and ultimately help generate actionable data to assess the effectiveness of malaria control strategies. Genomic data, coupled with geographic information systems data, can further identify clusters or hotspots of malaria transmission, parasite genetic and spatial connectivity, and parasite movement by human or mosquito mobility over time and space. In this study, we performed longitudinal genomic surveillance in a cohort of 70 participants over four years from different neighborhoods and households in Thiès, Senegal—a region of exceptionally low malaria transmission (entomological inoculation rate (EIR) less than 1). Genetic identity (identity by state) was established using a 24 single nucleotide polymorphism molecular barcode and a multivariable linear regression model was used to establish genetic and spatial relationships. Our results show clustering of genetically similar parasites within households and a decline in genetic similarity of parasites with increasing distance. One household showed extremely high diversity and warrants further investigation as to the source of these diverse genetic types. This study illustrates the utility of genomic data with traditional epidemiological approaches for surveillance and detection of trends and patterns in malaria transmission not only by neighborhood but also by household. This approach can be implemented regionally and countrywide to strengthen and support malaria control and elimination efforts.

WOMEN AND MALARIA—SPECIAL RISK AND APPROPRIATE CONTROL STRATEGY

PEDIATRICS ◽  
1995 ◽  
Vol 96 (1) ◽  
pp. 117-117
Author(s):  
R. Rueben
Keyword(s):  
Pregnant Women ◽  
Malaria Transmission ◽  
Falciparum Malaria ◽  
Malaria Control ◽  
Rural Areas ◽  
Control Strategies ◽  
Current Control ◽  
Control Measures ◽  
Control Programs ◽  
Utility Distribution

The factors that make pregnant women particularly vulnerable to morbidity and mortality with falciparum malaria and their relationship to current control strategies are reviewed. Pregnant women, particularly during their first pregnancy, are at greatest risk of severe falciparum malaria in areas of high and continuous malaria transmission and under conditions of unstable malaria in which they do not develop protective immunity. The author recommends chemoprophylaxis with chloroquine for pregnant women living in holoendemic and hyperendemic areas of Africa and Papua, New Guinea. Chloroquine is safe, but drug resistance has increasingly limited its utility, distribution is a formidable problem. In rural areas where poorly developed health care system are better developed and malaria transmission is less intense, the emphasis should be on early diagnosis and treatment. Women are potentially the key to the implementation of malaria control programs, yet recent studies indicate that underprivileged women frequently do not attend malaria clinics and are often missed in projects with passive surveillance. Additional research and community interventions are needed to enable women with malaria to obtain treatment and to involve them in malaria control measures at the village level.

scholarly journals Veterinary endectocides for malaria control and elimination: prospects and challenges

2020 ◽  
Vol 376 (1818) ◽  
pp. 20190810 ◽  
Author(s):  
Carlos Chaccour
Keyword(s):  
Malaria Transmission ◽  
Malaria Control ◽  
Malaria Elimination ◽  
Control Strategies ◽  
Intestinal Parasites ◽  
Scale Up ◽  
Malaria Risk ◽  
Theme Issue ◽  
Outdoor Biting ◽  
Domestic Livestock

Residual transmission is the persistence of malaria transmission after scale-up of appropriate vector control tools and is one of the key challenges for malaria elimination today. Although long associated with outdoor biting, other mosquito behaviours such as partly feeding upon animals contribute greatly to sustaining transmission. Peri-domestic livestock can be used as decoy to protect humans from blood-seeking vectors but this approach often leads to an increased malaria risk in a phenomenon known as zoopotentiation. Treating the said livestock with drugs capable of killing intestinal parasites as well as mosquitoes that feed upon them has the potential to tackle malaria through a previously unexplored mechanism. The advantages and challenges associated with this approach are briefly discussed here. Numerous references are purposely provided. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.

scholarly journals Optimizing systemic insecticide use to improve malaria control

2019 ◽  
Author(s):  
Hannah R. Meredith ◽  
Luis Furuya-Kanamori ◽  
Laith Yakob
Keyword(s):  
Mathematical Model ◽  
Malaria Transmission ◽  
Malaria Control ◽  
Mass Drug Administration ◽  
Mosquito Control ◽  
Pyrethroid Resistance ◽  
Control Strategies ◽  
Systemic Insecticide ◽  
Systemic Insecticides ◽  
Long Lasting Insecticidal Nets

AbstractLong lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood-hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that over-dependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability. Here, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through a mathematical model simulation. The review identified drugs from four classes commonly used in livestock and companion animals: avermectics, milbemycins, isoxazolines, and spinosyns. Simulations predicted that isoxazoline and spinosyn drugs were promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations. These findings will provide a guide for investigating and applying different systemic insecticides to achieve better mosquito control strategies.SignificanceThe widespread use of long lasting insecticidal nets (LLINs) and indoor residual spray has selected for mosquitoes that are resistant to pyrethroids or avoid exposure by feeding outdoors or on livestock. Systemic insecticides, drugs that render a host’s blood toxic to feeding mosquitoes, could be an effective control strategy for mosquitoes with pyrethroid resistance and/or outdoor feeding tendencies. Here, a number of existing systemic insecticide candidates are identified and their pharmacokinetic properties in different drug-host-route scenarios consolidated. These data were used to parameterise a mathematical model that illustrated the projected gains achievable in malaria control programmes already employing LLINs. The findings provide a guide for investigating and applying different systemic insecticides to improve mosquito control strategies and reduce malaria transmission.

scholarly journals The application of drones for mosquito larval habitat identification in rural environments: a practical approach for malaria control?

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Michelle C. Stanton ◽  
Patrick Kalonde ◽  
Kennedy Zembere ◽  
Remy Hoek Spaans ◽  
Christopher M. Jones
Keyword(s):  
Image Analysis ◽  
Malaria Control ◽  
Rural Areas ◽  
Near Infrared ◽  
Aquatic Vegetation ◽  
Temporal Trends ◽  
Scale Up ◽  
Larval Habitat ◽  
Habitat Characteristics ◽  
Rural Environments

Abstract Background Spatio-temporal trends in mosquito-borne diseases are driven by the locations and seasonality of larval habitat. One method of disease control is to decrease the mosquito population by modifying larval habitat, known as larval source management (LSM). In malaria control, LSM is currently considered impractical in rural areas due to perceived difficulties in identifying target areas. High resolution drone mapping is being considered as a practical solution to address this barrier. In this paper, the authors’ experiences of drone-led larval habitat identification in Malawi were used to assess the feasibility of this approach. Methods Drone mapping and larval surveys were conducted in Kasungu district, Malawi between 2018 and 2020. Water bodies and aquatic vegetation were identified in the imagery using manual methods and geographical object-based image analysis (GeoOBIA) and the performances of the classifications were compared. Further, observations were documented on the practical aspects of capturing drone imagery for informing malaria control including cost, time, computing, and skills requirements. Larval sampling sites were characterized by biotic factors visible in drone imagery and generalized linear mixed models were used to determine their association with larval presence. Results Imagery covering an area of 8.9 km2 across eight sites was captured. Larval habitat characteristics were successfully identified using GeoOBIA on images captured by a standard camera (median accuracy = 98%) with no notable improvement observed after incorporating data from a near-infrared sensor. This approach however required greater processing time and technical skills compared to manual identification. Larval samples captured from 326 sites confirmed that drone-captured characteristics, including aquatic vegetation presence and type, were significantly associated with larval presence. Conclusions This study demonstrates the potential for drone-acquired imagery to support mosquito larval habitat identification in rural, malaria-endemic areas, although technical challenges were identified which may hinder the scale up of this approach. Potential solutions have however been identified, including strengthening linkages with the flourishing drone industry in countries such as Malawi. Further consultations are therefore needed between experts in the fields of drones, image analysis and vector control are needed to develop more detailed guidance on how this technology can be most effectively exploited in malaria control.

Spatial and temporal trends and effects of contaminants in the Canadian Arctic marine ecosystem: a review

1999 ◽  
Vol 230 (1-3) ◽  
pp. 83-144 ◽  
Author(s):  
D Muir ◽  
B Braune ◽  
B DeMarch ◽  
R Norstrom ◽  
R Wagemann ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Temporal Trends ◽  
Canadian Arctic ◽  
Spatial And Temporal Trends

scholarly journals Spatial Disparities of COVID-19 Cases and Fatalities in United States Counties

2021 ◽  
Vol 18 (16) ◽  
pp. 8259
Author(s):  
Sarah L. Jackson ◽  
Sahar Derakhshan ◽  
Leah Blackwood ◽  
Logan Lee ◽  
Qian Huang ◽  
...  
Keyword(s):  
United States ◽  
Great Plains ◽  
Explanatory Power ◽  
Temporal Trends ◽  
The United States ◽  
First Year ◽  
Significant Case ◽  
Urban Rural ◽  
Spatial And Temporal Trends ◽  
Mitigation Policies

This paper examines the spatial and temporal trends in county-level COVID-19 cases and fatalities in the United States during the first year of the pandemic (January 2020–January 2021). Statistical and geospatial analyses highlight greater impacts in the Great Plains, Southwestern and Southern regions based on cases and fatalities per 100,000 population. Significant case and fatality spatial clusters were most prevalent between November 2020 and January 2021. Distinct urban–rural differences in COVID-19 experiences uncovered higher rural cases and fatalities per 100,000 population and fewer government mitigation actions enacted in rural counties. High levels of social vulnerability and the absence of mitigation policies were significantly associated with higher fatalities, while existing community resilience had more influential spatial explanatory power. Using differences in percentage unemployment changes between 2019 and 2020 as a proxy for pre-emergent recovery revealed urban counties were hit harder in the early months of the pandemic, corresponding with imposed government mitigation policies. This longitudinal, place-based study confirms some early urban–rural patterns initially observed in the pandemic, as well as the disparate COVID-19 experiences among socially vulnerable populations. The results are critical in identifying geographic disparities in COVID-19 exposures and outcomes and providing the evidentiary basis for targeting pandemic recovery.

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