Methodology: A protocol for membrane feeding assays to determine the infectiousness of P. falciparum naturally infected individuals to Anopheles gambiae
Research: Knowledge and practices on malaria in Tubu village, in a malaria-endemic area in northern Botswana: implications for interventions
The purpose of this survey was to assess peoples’ knowledge and perceptions on malaria among all the 71 households of Tubu village, located on the fringes of the Okavango Delta, in order to generate information to contribute to the malaria elimination programme being implemented by the Ministry of Health of Botswana. Generally, the high level of awareness and good practices shown by the community were ideal for sustainable implementation of community-based malaria intervention programmes. Misconceptions on malaria need to be corrected as these may have some detrimental effects on the Ministry of Health’s goal of malaria elimination in Botswana by 2016.
Research: Malaria transmission intensity and dynamics of clinical malaria incidence in a mountainous forest region of Ghana
Malaria transmission was assessed in four villages with different micro-ecological features in the forest zone of the Akwapim-Mampong Range in Ghana. Human landing catches(HLC) of mosquitoes were conducted and Plasmodium falciparum circumsporozoite rates were assessed by ELISA. Sporozoite prevalence, annual biting rates (ABR) and entomological inoculation rates (EIR) from the four study sites were compared with climatological and ecological data. Additionally trends in confirmed clinical malaria incidence from 2005 -2012 were examined. In total 1307 Anopheles gambiae s.l. and 54 An. funestus females were caught by HLC from November 2003 to August 2005. Sporozoites rates ranged from 4.0 to 10.2%, ABR from 371 to 1890 and EIR from 40 to 158. The ABR significantly influenced the parasite density (PD) of P. falciparum. Malaria transmission was intense and heterogeneous and corresponded to the micro-ecological differences. Malaria transmission in the early evening hours before people went to sleep was enough to sustain stable malaria. Scaling up preventive measures to reduce exposure to vectors will be effective in reducing parasitemia in children. Variations in transmission intensity must be considered when evaluating impact of control strategies and interventions such as the vaccine trials.
PhD thesis: Development and demise of Plasmodium liver stage parasites - The hunt for a Genetically Attenuated Malaria Vaccine
A considerable effort is currently underway to develop a malaria vaccine based on live Plasmodium falciparum sporozoites. The first requisite of a sporozoite vaccine is the guarantee of parasite arrest prior to the onset of the pathogenic blood stage. Immunisation with genetically attenuated parasites (GAP) that arrest in the liver forms a promising approach. Work in this thesis describes the development and characterisation of a P. berghei Δb9Δslarp GAP that fully arrests in the liver. Immunisation of multiple mouse strains with low numbers of Δb9Δslarp GAP resulted in sterile protection. The Δb9Δslarp GAP is there- fore the leading GAP vaccine candidate. Work in this the- sis further describes the effect of varying the parameters of sporozoite inoculation on parasite liver load. These findings provide a rationale for the design of clinical trials aimed at the administration of live attenuated P. falciparum sporozoites.
[Note: Full copy of PhD thesis attached]
Research: Intermittent preventive treatment with sulfadoxine-pyrimethamine versus weekly chloroquine prophylaxis for malaria in pregnancy in Honiara, Solomon Islands: a randomised trial
Solomon Islands is a malarious nation in the Pacific with all four human Plasmodium species present. Although chloroquine prophylaxis is recommended for pregnant women, itseffectiveness is uncertain because of chloroquine resistance. A parallel-group, open label, individually randomised superiority trial comparing weekly chloroquine prophylaxis (CQ) with intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) was conducted among pregnant women aged 15 to 49 years between August 2009- June 2010. The study shows that the use of SP for IPTp is not suitable for prevention of malaria in pregnancy in Solomon Islands, given the low malaria prevalence and the possible high prevalence of sulfa-allergy. Scaling up of transmission-reducing interventions has probably contributed to the malaria reduction in Honiara.
Editorial: The Grand Challenges Explorations (GCE) programme
This Editorial accompanies seven research articles for which the research was funded through Grand Challenge Exploration grants. Alan Magill is the newly appointed Director who oversees the development and implementation of strategies for the Gates foundation’s ultimate goal of the eradication of malaria using current tools and strategies as well as developing new generations of vaccines, diagnostics, and anti-malarial therapies to be used in novel and innovative ways. Steven Buchsbaum leads the Discovery & Translational Sciences team’s efforts to expand the Grand Challenges family of grant programs and associated partnerships to enhance their impact.
GCE Special: Using carnivorous plants to control malaria-transmitting mosquitoes
This GCE project set out to develop a novel way of controlling malaria-transmitting mosquitoes by deploying live, insect-eating plants around houses and in mosquito breeding sites. Field surveys were undertaken to collect and identify carnivorous plants. Aldrovanda vesiculosa and Utricularia reflexa were collected from swamps in various locations in Uganda and brought to the laboratory where they were kept in distilled water into which larvae of Anopeheles gambiae were introduced and the impact of the plants studied.
GCE Special: Plasmodium falciparum infection in “humanised liver” mice
This GCE project aimed to establish “humanised liver” mice capable of supporting the full development of the liver stages of human malaria parasites. This could provide an invaluable opportunity to study various aspects of human malaria without the use of human volunteers. This would include investigating the biology of human malaria parasites in vivo and testing the potency of various agents against human malaria infection. Furthermore, “humanised liver” mice would give us the means by which efficient and economical precursor analysis can be done prior to the more expensive human clinical trials.
GCE Special: Outdoor mosquito control using odour-baited devices: development and evaluation of a potential new strategy to complement indoor malaria prevention methods
To supplement current malaria prevention methods, and accelerate efforts towards elimination, this GCE project explores the use of outdoor mosquito control devices that mimic real humans, to attract and kill disease-transmitting vectors on a sustained basis. The idea (as envisioned in a GCE Phase I grant (2009) and Phase II grant (2011)) is to lure female Anopheles mosquitoes onto these outdoor ‘pseudo-hosts’, when positioned at optimally selected sites within or around human settlements, and then either trap these mosquitoes, contaminate them with substances that reduce their survival and ability to transmit disease or kill them instantly or within a few days after contact with the devices, thereby reducing exposure to mosquito bites and mosquito-borne pathogens.
GCE Special: Malaria β-Haematin in blood results in synergistic attenuation enhancement: Studies with a conventional multimode reader and a custom LED device
The aim of this GCE project was to develop a non-invasive method for diagnosing malaria. In order to do this, we sought to identify a novel optical property of β-haematin that gives it a robust optical signature. The optical signature needs to be readily detected with light-emitting diodes (LEDs) and photodiodes, which are compatible with low-cost operation in the developing world. The product is envisioned to be similar to a commercial fingertip pulse oximeter, which can be purchased for $20 and can be utilised for thousands of tests with a single battery.
