Toxoplasmosis, an infectious disease caused by the obligate intracellular protozoan parasite, poses varying degrees of risk, ranging from asymptomatic cases in immunocompetent individuals to severe, life-threatening conditions in immunocompromised individuals and developing fetuses, especially when infection occurs during early pregnancy. While the disease is endemic in Iraq, there is a notable lack of precise information regarding its seroprevalence among females of childbearing age and pregnant women, along with associated risk factors in the Zakho district. This cross-sectional study aimed to address this gap by determining the prevalence of anti-Toxoplasma gondii IgG and IgM antibodies using the ELISA assay. The study involved 610 females aged 18-79 years from various residential areas within Zakho district, Iraq. The findings revealed a seroprevalence of 32.46% for anti-Toxoplasma IgG antibodies and 8.86% for IgM antibodies. Significant variations in IgG antibody seroprevalence were observed across different age groups (P=0.008), with the highest prevalence noted among those aged 46-55 years (47.73%). Conversely, IgM antibody seroprevalence, while non-significant (P>0.05), displayed the highest rate of 10.05% among ages 18-25 years. The study identified residence as a variable significantly associated with toxoplasmosis. Additionally, contact with cats, marital status, a history of abortion, and the consumption of homemade food showed significant associations with anti-Toxoplasma IgM antibodies only. These findings strongly suggest that Toxoplasma gondii is a prevalent causative agent of infection in Zakho city, Iraq. This study contributes valuable insights into the seroprevalence and associated risk factors, providing a foundation for targeted interventions and further research in this region.

Detailed analyses of genetic diversity, antigenic variability, protein localization and immunological responses are vital for the prioritization of novel malaria vaccine candidates. Comprehensive approaches to determine the most appropriate antigen variants needed to provide broad protection are challenging and consequently rarely undertaken.
Here, we characterized PF3D7_1136200, which we named Asparagine-Rich Merozoite Antigen (ARMA) based on the analysis of its sequence, localization and immunogenicity. We analyzed IgG and IgM responses against the common variants of ARMA in independent prospective cohort studies in Burkina Faso (N = 228), Kenya (N = 252) and Mali (N = 195) using a custom microarray, Div-KILCHIP.
We found a marked population structure between parasites from Africa and Asia. African isolates shared 34 common haplotypes, including a dominant pair although the overall selection pressure was directional (Tajima\'s D = -2.57; Fu and Li\'s F = -9.69; P < 0.02). ARMA was localized to the merozoite surface, IgG antibodies induced Fc-mediated degranulation of natural killer cells and strongly inhibited parasite growth in vitro. We found profound serological diversity, but IgG and IgM responses were highly correlated and a hierarchical clustering analysis identified only three major serogroups. Protective IgG and IgM antibodies appeared to target both cross-reactive and distinct epitopes across variants. However, combinations of IgG and IgM antibodies against selected variants were associated with complete protection against clinical episodes of malaria.
Our systematic strategy exploits genomic data to deduce the handful of antigen variants with the strongest potential to induce broad protection and may be broadly applicable to other complex pathogens for which effective vaccines remain elusive.