Molecular interactions between a parasite and its host are key to the ability of the parasite to enter the host and persist. . . .

Host-pathogen interactions can be powerful drivers of adaptive evolution, shaping the patterns of molecular variation at the genes involved. . . .

The Plasmodium falciparum (P. . . .

PLoS ONE, Vol. 8, No. 2. (27 February 2013), e57434, doi:10.1371/journal.pone.0057434

The preferential invasion of particular red blood cell (RBC) age classes may offer a mechanism by which certain species of Plasmodia regulate their population growth. Asexual reproduction of the parasite within RBCs exponentially increases the number of circulating parasites; limiting this explosion in parasite density may be key to providing sufficient time for the parasite to reproduce, and for the host to develop a specific immune response. It is critical that the role of preferential invasion in infection is properly understood to model the within-host dynamics of different Plasmodia species. We develop a simulation model to show that limiting the range of RBC age classes available for invasion is a credible mechanism for restricting parasite density, one which is equally as important as the maximum parasite replication rate and the duration of the erythrocytic cycle. Different species of Plasmodia that regularly infect humans exhibit different preferences for RBC invasion, with all species except P. falciparum appearing to exhibit a combination of characteristics which are able to self-regulate parasite density.
Douglas Kerlin, Michelle Gatton

Cytoadherence of Plasmodium falciparum- infected erythrocytes to host cells is an important trait for parasite survival and has a major role in pathology of malaria disease. . . .

Background: Insecticide resistance in malaria vectors is a growing concern in many countries and requires immediate attention because of the limited chemical arsenal available for vector control. There is lack of systematic and standard monitoring data of malaria vector resistance in the endemic areas, which is essential for the ambitious goal of malaria elimination programme of China. Methods: In 2010, eight provinces from different malaria endemic region were selected for study areas. Bioassays were performed on F1 progeny of Anopheles sinensis reared from wild-caught females using the standard WHO susceptibility test with diagnostic concentrations of 0.25% deltamethrin and 4% DDT. Results: For An. sinensis, the results indicated that exposure to 0.25% deltamethrin of F1 families with mortalities ranging from 5.96% to 64.54% and less than 80% mortality to DDT at the diagnostic concentration of 4% across the study areas. Conclusions: Anopheles sinensis was completely resistant to both deltamethrin and DDT, and resistance to pyrethroid has risen strikingly compared to that recorded during 1990s. The results highlight the importance of longitudinal insecticide resistance monitoring and the urgent need for a better understanding of the status of insecticide resistance in this region.

Proceedings of the National Academy of Sciences, Vol. 110, No. 17. (23 April 2013), pp. 7020-7025, doi:10.1073/pnas.1305201110

Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures.
Sesh Sundararaman, Weimin Liu, Brandon Keele, Gerald Learn, Kyle Bittinger, Fatima Mouacha, Steve Ahuka-Mundeke, Magnus Manske, Scott Sherrill-Mix, Yingying Li, Jordan Malenke, Eric Delaporte, Christian Laurent, Eitel Ngole, Dominic Kwiatkowski, George Shaw, Julian Rayner, Martine Peeters, Paul Sharp, Frederic Bushman, Beatrice Hahn

A new, highly sensitive blood test that quickly detects even the lowest levels of malaria parasites in the body could make a dramatic difference in efforts to tackle the disease in the UK and across the world, according to new research.

Background: The Fulani ethnic group is known to have a lower susceptibility to Plasmodium falciparum infection than the Mossi. Methods: This commentary describes data from a recent cluster-randomized trial of community-wide screening and treatment of asymptomatic carriers of P. falciparum in 18 villages in Sapone, Burkina Faso. Results: The Fulani groups had a lower proportion of asymptomatic carriers at any occasion, a lower density of asexual forms and gametocytes of P. falciparum at baseline, and, in children under five years of age, lower rates of symptomatic malaria episodes per person-year than the Mossi.Discussion and conclusion: These data confirm previously reported differences in P. falciparum susceptibility between Fulani and Mossi.

Background: Malaria remains a substantial public health problem in Togo. An integrated child health campaign was conducted in Togo in October 2011. This campaign included a component of free distribution of 2,799,800 long-lasting, insecticide-treated nets (LLINs) to households throughout Togo. This distribution marked the first effort in Togo at universal LLIN coverage and was not targeted specifically to children under five years and pregnant women, but to all household members. This study reports the results of the LLIN distribution campaign in terms of bed net possession and utilization. Methods: A representative household survey was implemented during the rainy season nine months after the LLIN distribution component of the campaign. Some 6,015 households selected through two stages of probability proportion to size stratified random sampling were interviewed using a brief questionnaire that included a demographic section with questions on the number of household members and sleeping spaces, and a campaign participation section with questions used to evaluate non-LLIN aspects of the campaign. A net roster listed all nets and their characteristics, and a household roster listed all members and visitors with information about bed net use. The questions addressed different aspects of bed net and LLIN possession and utilization. Crude weighted frequencies, percentages, and t- tests of association were calculated using the Stata 12.0 Survey features. Results: Possession of at least one bed net and/ or LLIN increased from 41.3% to 96.7% (P <0.001). Household possession of at least one campaign LLIN was 93.3%. Report LLIN among pregnant women was 77.5% and 79.3% for children under five. For the general population LLIN use was 68.3%. Conclusions: Due to the gap in LLIN possession and use and the significant number of individuals reporting a lack of nets as a reason for non-use, additional national LLIN distribution campaigns with a stronger educational component need to be implemented in order increase the use of available LLINs and to reach and maintain universal coverage of LLINs in Togo. The LLIN distribution campaign focusing on universal coverage of the general population in Togo was more successful at increasing LLIN possession and use of children under five years and pregnant women than other campaigns focusing only on these target groups.

Background: To advance research on malaria, the outputs from existing studies and the data that fed into them need to be made freely available. This will ensure new studies can build on the work that has gone before. These data and results also need to be made available to groups who are developing public health policies based on up-to-date evidence. The Malaria Atlas Project (MAP) has collated and geopositioned over 50,000 parasite prevalence and vector occurrence survey records contributed by over 3,000 sources including research groups, government agencies and non-governmental organizations worldwide. This paper describes the results of a project set up to release data gathered, used and generated by MAP. Methods: Requests for permission to release data online were sent to 236 groups who had contributed unpublished prevalence (parasite rate) surveys. An online explorer tool was developed so that users can visualize the spatial distribution of the vector and parasite survey data before downloading it. In addition, a consultation group was convened to provide advice on the mode and format of release for data generated by MAP's modelling work. New software was developed to produce a suite of publication-quality map images for download from the internet for use in external publications. Conclusion: More than 40,000 survey records can now be visualized on a set of dynamic maps and downloaded from the MAP website on a free and unrestricted basis. As new data are added and new permissions to release existing data come in, the volume of data available for download will increase. The modelled data output from MAP's own analyses are also available online in a range of formats, including image files and GIS surface data, for use in advocacy, education, further research and to help parameterize or validate other mathematical models.

Measurement of the level and composition of maternal mortality depends on the definition used, with inconsistencies leading to inflated rates and invalid comparisons across settings. . . .

Men experience a higher burden of disease and lower life expectancy than women, but policies focusing on the health needs of men are notably absent from the strategies of global health organizations, according to a Viewpoint article in this week's Lancet.

Once introduced for biological pest control, Asian lady beetle populations have been increasing uncontrollably. Scientists from Giessen University and the Max Planck Institute for Chemical Ecology, Jena, Germany, have now found the reason for the animal's

CD8(+) T cells are specialized cells of the adaptive immune system capable of finding and eliminating pathogen-infected cells. . . .

Severe malaria, including cerebral malaria (CM) and placental malaria (PM), have been recognized to have many of the features of uncontrolled inflammation. . . .

The malaria parasite replicates within an intraerythrocytic parasitophorous vacuole (PV). . . .

CD8(+) T cells mediate immunity against Plasmodium liver stages. . . .

Female mosquitoes infected with malaria parasites are significantly more attracted to human odor than uninfected mosquitoes, according to new research. Scientists from the London School of Hygiene & Tropical Medicine will now attempt to find out how malar

Mosquitoes infected with the malarial parasite Plasmodium falciparum are significantly more attracted to human odors than uninfected mosquitoes, according to research published May 15 in the open access journal PLOS ONE by James Logan and colleagues from