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This article presents findings of a research previously published in the "Journal of Biological Chemistry," conducted by researcher A.L. Omara-Opyene. Plasmodial digestive vacuole plasmepsins are functionally redundant, which may limit their potential as malaria drug targets. The digestive vacuole plasmepsins PfPM1, PfPM2, PfPM4, and PfHAP (a histoaspartic proteinase) are four aspartic proteinases among 10 encoded in the Plasmodium falciparum malarial genome. These have been hypothesized to initiate and contribute significantly to hemoglobin degradation, a catabolic function essential to the survival of this intraerythrocytic parasite.

The article cites several studies on malaria. The first study reports that plasmodial digestive vacuole plasmepsins are functionally redundant, which may limit their potential as malaria drug targets. Because of their perceived significance, these plasmepsins have been proposed as potential targets for antimalarial drug development. Another study reports on the implied role of aspartic protease inhibition in the nitric oxide (NO)-mediated killing of the malarial parasite Plasmodium vivax. NO is known to possess antiparasitic activity towards Plasmodium species. Parasite proteases are currently considered to be promising targets for antimalarial chemotherapy.

Presents data on malaria vaccines from studies in France, Senegal and Great Britain. Report on conditional mutagenesis using site-specific recombination in Plasmodium (P.) berghei; Relation of the binding of immunoglobulin G to P. falciparum-infected erythrocytes with parasite endemicity; Analysis of a human complement receptor 1 polymorphism that reduces P. falciparum rosetting.

Reports on the research data in the area of malaria vaccines. Description of the strain-specific humoral response to a polymorphic malaria vaccine; Immune responses elicited in mice against a recombinant malaria vaccine based on Plasmodium vivax Duffy binding protein; Differences of non-immunogenic, non-protective peptides in alpha-helical position.

Presents research updates on Malaria vaccines, based on studies conducted by the researchers in the United States and Australia. Investigates the serine repeat antigen (SERA) gene family phylogeny in Plasmodium; Development of Plasmodium species infections in human aids malaria vaccine; Functions of Allelic polymorphisms in apical membrane antigen-1 for evasion of antibody-mediated inhibition in Plasmodium falciparum.

Cites several studies conducted by researchers in Great Britain and United States on malaria vaccines. Antibodies to the N-terminal block 2 of Plasmodium falciparum merozoite surface protein 1 are associated with protection against clinical malaria; Results of molecular dissection of the human antibody response to the structural repeat epitope of Plasmodium falciparum sporozoite from a protected donor; Inhibitory and neutral antibodies to Plasmodium falcipararum from ring structures with their antigen.

This article reports that scientists have developed a method to calculate liver-to-blood inocula, parasite growth rates, and pre-erythrocytic vaccine efficacy, using serial quantitative polymerase chain reaction studies of volunteers challenged with malaria sporozoites. The study was conducted by Philip Bejon and colleagues at the University of Oxford, Oxford, England. Bejon and his coauthors published their findings in the "Journal of Infectious Diseases Calculation." They calculated the number and growth rate of Plasmodium falciparum parasites emerging in recipients of candidate preerythrocytic malaria vaccines and unvaccinated control subjects undergoing mosquito-bite challenge.

This article presents findings of a research on Plasmodium merozoite conducted by Christian A. Darko and published in the journal "Infection and Immunity." The 42-kD fragment of merozoite surface protein 1(MSP 1) of Plasmodium falciparum strain FVO expressed in Escherichia coli protects Aotus nancymai against challenge with homologous erythrocytic-stage parasites. The trial included two control groups, one vaccinated with the sexual-stage-specific antigen of Plasmodium vivax, Pvs25, as a negative control, and the other vaccinated with baculovirus-expressed MSP1[42] (FVO) as a positive control. The study concluded that soluble MSP1[42] (FVO) expressed in E. coli offers excellent promise as a component of a vaccine against erythrocytic-stage falciparum malaria

Reports on a meeting by state health officials regarding West Nile virus in Oregon on March 8, 2005. Role of mosquito bites in the spread of the infection; Percentage of infections that resulted in mild illness; Number of horses that were infected with the virus in 2004; Prevention and control of the virus.

The article informs that the selection for virulent dengue viruses occurs in humans and mosquitoes. According to the Southwest Foundation Biomedical Researh by R. Cologna and colleagues in San Antonio, Texas, dengue is the most common mosquito-borne viral disease in humans. The spread of both mosquito vectors and viruses has led to the resurgence of epidemic dengue fever (a self-limited flu-like syndrome) and the emergence of dengue hemorrhagic fever (severe dengue with bleeding abnormalities) in urban centers of the tropics. Cologna and colleagues published their study in the "Journal of Virology."

This article cites a study which says that Various heterologous prime-boost vaccine regimens using DNA and viral vectors demonstrated differential immunogenicity in healthy volunteers. Heterologous prime-boost vaccination has been shown to be an efficient way of inducing T cell responses in animals and in humans. Researchers have used three vaccine vectors, naked DNA, modified vaccinia virus Ankara (MVA), and attenuated fowlpox strain, FP9, for prime-boost vaccination approaches against Plasmodium falciparum malaria in humans. The research was conducted by Jennie M. Vuola and colleagues. Vuola and associates published the results of their research in the "Journal of Immunology."

This article presents information regarding West Nile summit for Oregon. The meeting included county public health workers and hospital officials from around the state. If Oregon follows the pattern of other states, this year could see a large number of human cases. Usually, states experience a few cases one year and then see a sharp increase the following year. A drop-off occurs after the spike. West Nile made its Oregon debut in 2004. It sickened 5 people, and killed 19 birds and 22 horses. Most of the dead birds were found in Southern Oregon.

The article cites a study which reveals that the Plasmodium circumsporozoite protein is proteolytically processed during cell invasion. The circumsporozoite protein (CSP) is the major surface protein of Plasmodium sporozoites, the infective stage of malaria. Although CSP has been extensively studied as a malaria vaccine, wrote researchers Alida Coppi and colleagues at New York University. Results suggest that the highly conserved region 1, found just before the repeat region, contains the cleavage site. Coppi and associates published their study in the "Journal of Experimental Medicine."

The article cites a study which reveals that the 42-kD fragment of merozoite surface protein 1 of Plasmodium falciparum strain FVO expressed in Escherichia coli protects Aotus nancymai against challenge with homologous erythrocytic-stage parasites. Researchers Christian A. Darko and colleagues that the clinical-grade recombinant protein retained some important elements of correct structure, as it was reactive with several functional, conformation-dependent monoclonal antibodies raised against P. falciparum malaria parasites. Darko and associates published their study in the journal "Infection and Immunity."

The article cites a study which outlines allele specificity of naturally acquired antibody responses against Plasmodium falciparum apical membrane antigen 1. Researchers Alfred Cortes and collaborators at the Papua New Guinea Institute of Medical Research and La Trobe University in Australia characterized the antibody responses against AMA1 in 262 individuals from Papua New Guinea exposed to malaria by using different allelic forms of the full AMA1 ectodomain and some individual subdomains. Cortes and his colleagues published their study in the journal "Infection and Immunity."

Examines the association of a SICAvar switching event in Plasmodium knowlesi with the DNA rearrangement of conserved 3' non-coding sequences. Outcome of DNA rearrangement; Expression of Plasmodium knowlesi variant antigens at the surface of infected erythrocytes; Genetic function in the stage-specific and developmentally regulated post-transcriptional gene silencing of variant antigen transcripts.

Presents new data on malaria vaccines from researchers in France and the U.S. Completion of a preliminary structural analysis of the ectoplasmic region of apical membrane antigen 1 from Plasmodium vivax, a malaria vaccine candidate; Production of the subdomains of the Plasmodium falciparum apical membrane antigen 1 ectodomain; Consideration of Plasmodium ookinete-secreted proteins secreted through a common micronemal pathway as the target of blocking malaria transmission.

Cites a study from Thailand characterizing the behavioral responses of the mosquito malaria vector Aedes aegypti to deltamethrin. Examination of Aedes aegypti strains under laboratory-controlled conditions using an excito-repellency test system; Manifestation of significant behavioral escape responses by the strains when exposed to deltamethrin; Observance of high percentage of mortality from laboratory strains that failed to escape.

Cites a study in England mapping malaria parasite-inhibitory antibody epitopes on Plasmodium falciparum merozoite surface protein-1(MSP1) [19] using transverse relaxation optimized spectroscopy NMR. Consideration of MSP1 [19] as the leading candidate antigen for the development of vaccine against the blood stages of the malaria parasite; Evaluation of P. falciparum MSP1[19] complexes with Fab fragments from three monoclonal antibodies; Observation of a close relationship between binding sites of the two inhibitory antibodies, which are distinct from the location of the non-inhibitory antibody.

Discovers evidence for the involvement of VAR2CSA in pregnancy-associated malaria. Accumulation of parasite-infected erythrocytes (IEs) in the placenta; Acquisition of anti-VSA[PAM] immunoglobulin G as a function of parity; Expression of VAR2CSA on the surface of CSA-selected IEs.

Presents a review on the possible reasons for the need for multiple infections to acquire immunity to malaria by investigators in England. Occurrence of evasion and modulation of host immune responses; Achievement of a protective immunity to severe pathology; Requirement of a persistent or frequent exposure to antigen.

Evaluates the status of West Nile virus (WNV) epidemic worldwide. Probability of WNV distribution to increase in Asia and Europe; Implications for disease prevention; Speculations on the consequences of the adaptation of WNV to new ecosystems.

Investigates the HLA class II and antibody responses to circumsporozoite protein (CSP) repeats of Plasmodium vivax in individuals naturally exposed to malaria in Brazil. Prevalence of immunoglobulin G antibodies for each one of the P. vivax CSP repeats; Examination of the potential relationship between HLA-DQB1 allele profile and antibody response to the CSP repeats of P. vivax; Modulation of the antibody responses to the CSP repeats of P. vivax variants by HLA class II molecules in malaria naturally exposed individuals.

This article presents information on the Plasmodium circumsporozoite protein that is proteolytically processed during cell invasion. The circumsporozoite protein (CSP) is the major surface protein of Plasmodium sporozoites, the infective stage of malaria. Here, the study show that CSP is proteolytically cleaved by a papain family cysteine protease of parasite origin. The data suggest that the highly conserved region found just before the repeat region, contains the cleavage site, according to Alida Coppi and colleagues. Cleavage occurs on the sporozoite surface when parasites contact target cells. Inhibitors of CSP processing inhibit cell invasion in vitro, and treatment of mice with E-64, a highly specific cysteine protease inhibitor, completely inhibits sporozoite infectivity in vivo. Coppi and associates published their study in the "Journal of Experimental Medicine."

The article reports that researchers have outlined allele specificity of naturally acquired antibody responses against Plasmodium falciparum apical membrane antigen 1 in a recent issue of "Infection and Immunity." Antibody responses against proteins located on the surface or in the apical organelles of merozoites are presumed to be important components of naturally acquired protective immune responses against the malaria parasite Plasmodium falciparum. However, many merozoite antigens are highly polymorphic, and antibodies induced against one particular allelic form might not be effective in controlling growth of parasites expressing alternative forms. The apical membrane antigen 1 (AMA1) is a polymorphic merozoite protein that is a target of naturally acquired invasion-inhibitory antibodies and is a leading asexual-stage vaccine candidate.

The article cites a study conducted by R. Cologna and collaborators, published in the "Journal of Virology," which states that the selection for virulent dengue viruses occurs in humans and mosquitoes. Dengue is the most common mosquito-borne viral disease in humans. The spread of both mosquito vectors and viruses has led to the resurgence of epidemic dengue fever and the emergence of dengue hemorrhagic fever in urban centers of the tropics. Infection and growth experiments showed that dengue serotype 2 viruses causing dengue hemorrhagic fever epidemics can outcompete viruses that cause dengue fever only.

This article reports that various heterologous prime-boost vaccine regimens using DNA and viral vectors demonstrated differential immunogenicity in healthy volunteers. The study was conducted by Jennie M. Vuola and colleagues at the University of Oxford, Oxford, England. Vuola and associates published the results of their research in the "Journal of Immunology." According to a study from England, heterologous prime-boost vaccination has been shown to be an efficient way of inducing T cell responses in animals and in humans.

Reports on the pregnancy-associated malaria vaccines discussed by researchers in the "Journal of Experimental Medicine." Claim that the recent discoveries regarding the molecular basis of malaria pathogenesis have led to a better understanding of the interactions between host and parasite; Availability of immediate prospects for syndrome-specific antimalaria vaccines.

Reports on the findings of a study from the U.S. that information on mixed Plasmodium species infections in human aids malaria vaccine development. Inclusions in the factors contributing to heterogeneous parasite species and disease distribution; Importance of careful examination of methods used to detect the parasites; Publication of this study.

Discusses male-specific insecticide resistance and mosquito transgene dispersal by scientists in England. Development of methods to spread disease-blocking transgenes through mosquito populations; Significance of the resulting increase in mean longevity of males carrying the construct under insecticide treatment; Possibility of producing constructs where any potential risk of loss of male-specific expression would be negligible.

Reports on the study that intravital microscopy indicates antibody-mediated immobilization of Plasmodium berghei sporozoites injected into skin by mosquitoes. Initiation of malaria infection by sporozoites; Presentation of a direct morphological evidence of mosquito through the use of intravital microscopy of the skin; Role of anti-sporozoite antibodies in blocking sporozoite invasion.

Reports the results of a molecular dissection of the human antibody response to the structural repeat epitope of Plasmodium falciparum sporozoite from a protected donor. Identification of the circumsporozoite surface protein as the primary target of human antibodies against Plasmodium falciparum sporozoites; Implication of the analysis of selected antibody fragments; Analysis of the dissection of the protective antibody response against the repeat epitope.

Reports on the study which examined the efficacy of inhibitors involved in spermidine metabolism in Plasmodium falciparum, Anopheles stephensi and Trypanosoma evansi. Identification of agmatine as a growth inhibitor of P. falciparum; Observations noted from the study; Indication that the two spermidine analogues were moderate inhibitors in vitro.

Reports that scientists from the Netherlands have performed a statistical analysis of malaria parasitemia measured by a quantitative real-time polymerase chain reaction. Importance of clinical trials in the evaluation of safety and efficacy of malaria vaccines; Use of quantitative real-time polymerase chain reaction to measure Plasmodium falciparum malaria parasitemia; Development of the statistical model to estimate pre-patent periods and parasite multiplication of blood stages.