Search

Malaria poses a significant global health challenge, resulting in approximately 600,000 deaths each year. Individuals living in regions with endemic malaria have the potential to develop partial immunity, thanks in part to the presence of anti-plasmodium antibodies. As efforts are made to optimize and implement strategies to reduce malaria transmission and ultimately eliminate the disease, it is crucial to understand how these interventions impact naturally acquired protective immunity. To shed light on this, our study focused on assessing antibody responses to a carefully curated library of P. falciparum recombinant proteins (n = 691) using samples collected from individuals residing in a low-malaria-transmission region of Thailand. We conducted the antibody assays using the AlphaScreen system, a high-throughput homogeneous proximity-based bead assay that detects protein interactions. We observed that out of the 691 variable surface and merozoite stage proteins included in the library, antibodies to 268 antigens significantly correlated with the absence of symptomatic malaria in an univariate analysis. Notably, the most prominent antigens identified were P. falciparum erythrocyte membrane protein 1 (PfEMP1) domains. These results align with our previous research conducted in Uganda, suggesting that similar antigens like PfEMP1s might play a pivotal role in determining infection outcomes in diverse populations. To further our understanding, it remains critical to conduct functional characterization of these identified proteins, exploring their potential as correlates of protection or as targets for vaccine development. [ABSTRACT FROM AUTHOR]

Background: Health personnel (HP) are at risk of varicella zoster virus (VZV) infection, thus varicella immunity is needed or serious consequences to HP and patient care can result. A varicella immunity profile is not routinely checked in our pre-placement program. The aim of the present study was to determine the proportion of new HP with varicella immunity. Materials and Methods: The research design was a descriptive study. The study population was 258 HP who met the inclusion criteria. The sample of 214 HP (82.9%) participated in the study. Varicella immunity history was obtained using a pre-placement questionnaire. The HP who already had complete vaccination were concluded to be the immunized group without immunologic blood test evidence. Only non vaccinated HP would get serologic test for varicella virus. A serological test for varicella virus was performed using an enzyme-linked immunosorbent assay (Euroimmun, anti-VZV ELISA IgG, Hausen Bernstein Co., Ltd).The proportion of positive immunity was used to describe overall immunity. Results: Twenty-two percent (47/214) of HP reported having a complete history of varicella vaccination. History of varicella infection was reported in 57.9% (124/214) of participants. The HP who had neither history of infection nor vaccination accounted for 10.7% (23/214). Seven percent of the HP were unsure about their respective infection history (15/214). There were 167 HP who did not have varicella vaccination, 89.2% (149/167) of them were positive to varicella IgG. The total proportion of immunizedpersonnel was thus 91.6% (196/214). Conclusion: The majority of new HP had varicella immunity; re-assessing immunity status serologically will prevent unnecessary vaccinations and insure all HP have varicella immunity [ABSTRACT FROM AUTHOR]

Background: Reductions in malaria transmission decrease naturally acquired immunity, which may influence the emergence of Plasmodium falciparum artemisinin-resistant phenotypes and genotypes over time.Methods: Antibodies specific for P. falciparum antigens were determined in uncomplicated hyperparasitemic malaria patients over a 10-year period of declining malaria transmission and emerging artemisinin resistance in northwestern Thailand. We investigated the association between antibody levels and both parasite clearance time (PCt½) and artemisinin resistance-associated kelch13 genotypes over time.Results: Immunity to P. falciparum declined prior to 2004, preceding the emergence of artemisinin resistance-associated genotypes and phenotypes (maximum mean change in antibody level per year: anti-MSP142 = -0.17; 95% confidence interval [CI] = -.31 to -.04; P = .01). In this period of declining immunity, and in the absence of kelch13 mutations, PCt½ increased. Between 2007 and 2011, levels of antibodies fluctuated, and higher antibody levels were associated with faster PCt½ (maximum yearly change in PCt½, in hours: EBA140rII = -0.39; 95% CI = -.61 to -.17; P < .001).Conclusions: Understanding the impact of changing transmission and immunity on the emergence of artemisinin resistance is important particularly as increased malaria control and elimination activities may enhance immunological conditions for the expansion of artemisinin-resistant P. falciparum. [ABSTRACT FROM AUTHOR]