Rapid development of vaccines for COVID-19 has relied on the application of existing vaccine technologies. This work examines the maturity of ten technologies employed in candidate vaccines (as of July 2020) and NIH funding for published research on these technologies from 2000-2019. These technologies vary from established platforms, which have been used successfully in approved products, to emerging technologies with no prior clinical validation.
View Article and Find Full Text PDFElevation is an important determinant of ecological community composition. It integrates several abiotic features and leads to strong, repeatable patterns of community structure, including changes in the abundance and richness of numerous taxa. However, the influence of elevational gradients on microbes is understudied relative to plants and animals.
View Article and Find Full Text PDFBackground: One of the concerns for future malaria epidemiology is the elevated risks of malaria around an ever-increasing number of dam sites. Controlling larval populations around reservoirs behind dams by manipulating the water levels of reservoirs could be an effective and sustainable measure for suppressing malaria epidemics; however, the effectiveness of the water-level manipulation and the contributing mechanisms have been poorly studied. In this paper, we focus on how water recession may lead to larval stranding.
View Article and Find Full Text PDFBackground: International financing for malaria increased more than 18-fold between 2000 and 2011; the largest source came from The Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund). Countries have made substantial progress, but achieving elimination requires sustained finances to interrupt transmission and prevent reintroduction. Since 2011, global financing for malaria has declined, fueling concerns that further progress will be impeded, especially for current malaria-eliminating countries that may face resurgent malaria if programs are disrupted.
View Article and Find Full Text PDFSoil pits excavated for home construction are important larval habitats for malaria vectors in certain parts of Africa. Borrow pits in diverse stages of ecological succession in a maize-farming region of Western Ethiopia were surveyed to assess the relationships between stage of succession and the structure and composition of invertebrate and plant communities, with particular attention to Anopheles gambiae s.l.
View Article and Find Full Text PDFAnti-malaria interventions that rely on insecticides can be compromised by insecticide-resistance alleles among malaria vectors. We examined frequency changes of resistance alleles at two loci, knockdown resistance (kdr) and acetylcholinesterase-1 (ace-1), which confer resistance to pyrethroids and DDT, and carbamates, respectively. A total of 7,059 Anopheles gambiae sensu stricto mosquitoes were analyzed from multiple sites across continental Equatorial Guinea.
View Article and Find Full Text PDFNO MAS (NM) mosquito repellent was evaluated in two farming villages (4 km apart) in the Kassena Nankana district of northern Ghana. We determined its efficacy against local malaria vectors, degree of user acceptance, and its effect on malaria prevalence in households using insecticide-treated bed nets. The average protective efficacy of NM against Anopheles mosquitoes over 9 hours was 89.
View Article and Find Full Text PDFAnopheles melas is a brackish water-breeding member of the Anopheles gambiae complex that is distributed along the coast of West Africa and is a major malaria vector within its range. Because little is known about the population structure of this species, we analysed 15 microsatellite markers and 1161 bp of mtDNA in 11 A. melas populations collected throughout its range.
View Article and Find Full Text PDFBackground: Indoor-based anti-vector interventions remain the preferred means of reducing risk of malaria transmission in malaria endemic areas around the world. Despite demonstrated success in reducing human-mosquito interactions, these methods are effective solely against endophilic vectors. It may be that outdoor locations serve as an important venue of host seeking by Anopheles gambiae sensu lato (s.
View Article and Find Full Text PDFWe assessed the structure and latitudinal selection that might result in sensitivities to critical day-lengths that trigger diapause between Culex pipiens populations distributed along North-South and East-West axes in eastern North America. Strong population structure between Cx. p.
View Article and Find Full Text PDFIn 2005, São Tomé e Príncipe began an initiative aimed at reducing malaria-related mortality to zero. The program included mass coverage with two antivector intervention methods (indoor residual spraying and long-lasting insecticidal nets), artemisinin-based combination therapy, and intermittent preventive therapy in pregnancy with sulfadoxine-pyrimethamine. At the end of 2007, three years after intensified interventions began, malaria-attributed outpatient consultations, hospitalizations, and deaths decreased by more than 85%, 80%, and 95%, respectively, in all age groups.
View Article and Find Full Text PDFAnthony Kiszewski discusses the implications of a new study that finds that global malaria funding remains inadequate.
View Article and Find Full Text PDFBull World Health Organ
August 2007
Objective: To provide the international community with an estimate of the amount of financial resources needed to scale up malaria control to reach international goals, including allocations by country, year and intervention as well as an indication of the current funding gap.
Methods: A costing model was used to estimate the total costs of scaling up a set of widely recommended interventions, supporting services and programme strengthening activities in each of the 81 most heavily affected malaria-endemic countries. Two scenarios were evaluated, using different assumptions about the effect of interventions on the needs for diagnosis and treatment.
To determine whether the Culex (Diptera: Culicidae) mosquitoes that transmit West Nile virus (family Flaviviridae, genus Flavivirus, WNV) in the northeastern United States seek hosts and oviposit contemporaneously, we recorded when these mosquitoes attacked caged birds and when they deposited eggs. They traversed oviposition sites most frequently approximately 2 h after astronomical sunset, and eggs generally were deposited at that time. Although they most frequently approached avian hosts approximately 2 h after sunset during midsummer, they are more opportunistic during mid- to late fall.
View Article and Find Full Text PDFVector Borne Zoonotic Dis
September 2006
We determined whether aerosol applications of resmethrin, delivered from the road, suppress the reproductive activity of Culex pipiens pipiens and Cx. restuans mosquitoes in suburban sites located near Boston. Oviposition implies a prior blood-feeding event and hence a potential West Nile virus (WNV) transmission-related event.
View Article and Find Full Text PDFAlthough maize pollen is known to provide nutrition for larval anopheline mosquitoes, the epidemiologic relationship between maize agriculture and malaria transmission has never been defined. To determine whether recent changes in malaria transmission in Ethiopia might be linked to the spread of maize as a commercial crop, we compared malaria transmission and maize cultivation intensity in 21 villages in the Bure District of northwestern Ethiopia where maize cultivation has recently expanded. The cumulative incidence in high maize cultivation areas was 9.
View Article and Find Full Text PDFAm J Trop Med Hyg
August 2004
The role of epidemic malaria as a distinct epidemiologic entity posing unique intervention challenges is reviewed from a global perspective. Epidemic malaria derives from particular interactions of vectors, parasites, and various environmental and anthropogenic determinants. Malaria epidemics generally afflict immunologically vulnerable populations, and their explosiveness can strain the capacity of health facilities, causing case fatality rates to increase five-fold or more during outbreaks.
View Article and Find Full Text PDFTo relate stability of malaria transmission to biologic characteristics of vector mosquitoes throughout the world, we derived an index representing the contribution of regionally dominant vector mosquitoes to the force of transmission. This construct incorporated published estimates describing the proportion of blood meals taken from human hosts, daily survival of the vector, and duration of the transmission season and of extrinsic incubation. The result of the calculation was displayed globally on a 0.
View Article and Find Full Text PDFTo explain how larval Anopheles arabiensis Patton feed effectively in the turbid water in which they frequently develop, we determined whether an extractable component of maize, Zea mays L., pollen enhances feeding by these mosquitoes. Maturing maize produces a copious amount of wind-borne pollen that is nutritious enough and produced over a sufficient period to support the development of at least one generation of anopheline mosquitoes.
View Article and Find Full Text PDFTo determine whether proximity to flowering maize enhances the development of larval anopheline mosquitoes breeding in turbid water and when crowded, we evaluated the development of larval Anopheles arabiensis under various conditions of turbidity, larval density, and proximity to pollen-shedding maize in simulated breeding puddles in a malaria-endemic site. In naturally formed puddles, water turbidity, as well as larval density, increased as the rainy season progressed. In sites remote from flowering maize, more pupae developed and the resulting adults were larger in relatively clear water than in turbid water, and larval crowding inhibited development.
View Article and Find Full Text PDFQuesting female blacklegged ticks, Ixodes scapularis, Say in Massachusetts rarely bear more than one endospermatophore in their reproductive tracts. We evaluated the cause of this nonrandom distribution by examining the stability of endospermatophore retention in females and the effect of prior insemination of females on the copulatory behavior of male ticks. Endospermatophores were retained without degradation in unfed female ticks for >1 yr at 5 degrees C and for at least 4 mo at 21 degrees C.
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