BackgroundSeroepidemiology can provide evidence for temporal changes in malaria transmission and is an important tool to evaluate the effectiveness of control interventions. During the early 2000s, Vanuatu experienced an acute increase in malaria incidence due to a lapse in funding for vector control. After the distribution of subsidised insecticide-treated nets (ITNs) resumed in 2003, malaria incidence decreased in the subsequent years. This study was conducted to find the serological evidence supporting the impact of ITN on exposure to Anopheles vector bites and parasite prevalence.MethodsOn Ambae Island, blood samples were collected from 231 and 282 individuals in 2003 and 2007, respectively. Parasite prevalence was determined by microscopy. Antibodies to three Plasmodium falciparum (PfSE, PfMSP-119, and PfAMA-1) and three Plasmodium vivax (PvSE, PvMSP-119, and PvAMA-1) antigens, as well as the Anopheles-specific salivary antigen gSG6, were detected by ELISA. Age-specific seroprevalence was analysed using a reverse catalytic modelling approach to estimate seroconversion rates (SCRs).ResultsParasite rate decreased significantly (P < 0.001) from 19.0% in 2003 to 3.2% in 2007, with a shift from P. falciparum predominance to P. falciparum-P. vivax co-dominance. Significant (P < 0.001) decreases were observed in seroprevalence to all three P. falciparum antigens but only two of three P. vivax antigens (except PvAMA-1; P = 0.153), consistent with the more pronounced decrease in P. falciparum prevalence. Seroprevalence to gSG6 also decreased significantly (P < 0.001), suggesting that reduced exposure to vector bites was important to the decrease in parasite prevalence between 2003 and 2007. Analyses of age-specific seroprevalence showed a three-fold decrease in P. falciparum transmission, but the evidence for the decrease in P. vivax transmission was less clear.ConclusionsSerological markers pointed to the effectiveness of ITNs in reducing malaria prevalence on Ambae Island between 2003 and 2007. The recombinant gSG6 antigen originally developed to indicate exposure to the Afrotropical vector An. gambiae may be used in the Pacific to complement the traditional measure of entomological inoculation rate (EIR).

Mosquito immune cells, known as hemocytes, are integral to cellular and humoral responses that limit pathogen survival and mediate immune priming. However, without reliable cell markers and genetic tools, studies of mosquito immune cells have been limited to morphological observations, leaving several aspects of their biology uncharacterized. Here, we use single-cell RNA sequencing (scRNA-seq) to characterize mosquito immune cells, demonstrating an increased complexity to previously defined prohemocyte, oenocytoid, and granulocyte subtypes. Through functional assays relying on phagocytosis, phagocyte depletion, and RNA-FISH experiments, we define markers to accurately distinguish immune cell subtypes and provide evidence for immune cell maturation and differentiation. In addition, gene-silencing experiments demonstrate the importance of lozenge in defining the mosquito oenocytoid cell fate. Together, our scRNA-seq analysis provides an important foundation for future studies of mosquito immune cell biology and a valuable resource for comparative invertebrate immunology.

Mosquito immune cells, known as hemocytes, are integral to cellular and humoral responses that limit pathogen survival and mediate immune priming. However, without reliable cell markers and genetic tools, studies of mosquito immune cells have been limited to morphological observations, leaving several aspects of their biology uncharacterized. Here, we use single-cell RNA sequencing (scRNA-seq) to characterize mosquito immune cells, demonstrating an increased complexity to previously defined prohemocyte, oenocytoid, and granulocyte sub-types. Through functional assays relying on phagocytosis, phagocyte depletion, and RNA-FISH experiment, we define markers to accurately distinguish immune cell sub-types and provide evidence for immune cell maturation and differentiation. In addition, gene-silencing experiments demonstrate the importance of lozenge in defining the mosquito oenocytoid cell fate. Together, our scRNA-seq analysis provides an important foundation for studies of mosquito immune cell biology and a valuable resource for comparative invertebrate immunology.

The malaria parasite Plasmodium falciparum causes more than half a million deaths per year. The current treatment regimen targets the symptom-causing blood stage inside the human host.

Programmed identification of white platelets (WBCs) stays an uncertain issue in medicinal imaging. The first step in this algorithm is to detect a white blood cell (Lymphocyte) and then segments the Cytoplasm and Nucleus in this cell. This was done by using image processing Techniques. The suggested method depending on the binary conversion of red, blue and hue compounds depending on threshes values. These values were calculated from histogram analysis within specific ranges. The proposed algorithm was compared with several other algorithms for detection by using an accuracy scale in the detection. where the proposed algorithm obtained a high distinction accuracy reached 98% compared to other methods.

No abstract

No abstract

Host-parasite interactions include complex interplays between an invading and a defending organism, each continuously adapting to gain the upper hand. The protozoan parasite, Toxoplasma gondii, can invade every nucleated cell type in a vertebrate host, including immune cells while the host mounts a protective response. Here, we utilize Dual-scSeq to parse out heterogeneous transcription of bone marrow-derived dendritic cells (BMDCs) infected with T. gondii type I, RH (LDM) or type II, ME49 (PTG) parasites, over multiple time points post infection. We find that the two parasite lineages distinctly manipulate two subpopulations of infected BMDCs. Co-expression networks establish host and parasite genes, with implications for modulation of host immunity and host-pathogen interactions. Integration of published data validates immune pathways and suggests novel candidate genes involved in host-pathogen interactions. This study aims to provide a comprehensive resource for future characterization of host-pathogen interplay among other protozoan parasites within their host niches, as well as that of bacterial and viral pathogens.