Background Intensive malaria transmission along international borders is a significant impediment to malaria elimination in the Greater Mekong Subregion (GMS) of Southeast Asia. Passive case detection (PCD) was used to study the dynamics and trends of malaria transmission at the China–Myanmar border to provide epidemiologic information for improved malaria control. Methods PCD was conducted in one hospital and 12 clinics near the Laiza town in northeast Myanmar from 2011 to 2016. Clinical malaria was diagnosed by microscopy and demographic information was captured using a structured questionnaire at the time of the patient’s presentation for care. Results Over the study period, 6175 (19.7%) malaria cases were confirmed by microscopy from 31,326 suspected cases. The four human malaria parasite species were all identified, with Plasmodium vivax and Plasmodium falciparum accounting for 5607 (90.8%) and 481 (7.8%) of the confirmed cases, respectively. In contrast to the steady decline of malaria in the general GMS, the study site had an upward trend of malaria incidence with vivax malaria outbreaks in 2013 and 2016. Adult males, children under the age of 15, and those with occupations such as farming, being a soldier or student, had significantly higher risks of clinical malaria compared to having fevers from other aetiologies. A self-reported history of clinical malaria was also associated with a higher risk of confirmed malaria. Conclusions The China–Myanmar border area has experienced an overall upward trend of malaria incidence in recent years with P. vivax becoming the predominant species. Evidence-based control strategies need to focus on high-risk populations.

Deletion of the pfhrp2 gene in Plasmodium falciparum can lead to false-negative rapid diagnostic test (RDT) results, constituting a major challenge for evidence-based malaria treatment. Here we analyzed the whole genome sequences of 138 P. falciparum clinical samples collected from the China-Myanmar boarder for pfhrp2 and pfhrp3 gene deletions. We found pfhrp2 and pfhrp3 deletions in 9.4% and 3.6% of samples, respectively, with no samples harboring deletions of both genes. The pfhrp2 deletions showed 2 distinct breakpoints, representing 2 different chromosomal deletion events. A phylogenetic analysis performed using genome-wide single-nucleotide polymorphisms revealed that the 2 pfhrp2 breakpoint groups as well as all the pfhrp3-negative parasites formed separate clades, suggesting they might have resulted from clonal expansion of pfhrp2- and pfhrp3-negative parasites. These findings highlight the need for urgent surveys to determine the prevalence of pfhrp2-negative parasites causing false-negative RDT results and a plan for switching of RDTs pending the survey results.

CD47 is an antiphagocytic “don’t eat me” signal that inhibits programmed cell removal of self. As red blood cells (RBCs) age they lose CD47 expression and become susceptible to programmed cell removal by macrophages. CD47−/− mice infected with Plasmodium yoelii, which exhibits an age-based preference for young RBCs, were previously demonstrated to be highly resistant to malaria infection. Our study sought to test the therapeutic benefit of CD47 blockade on ameliorating the clinical syndromes of experimental cerebral malaria (ECM), using the Plasmodium berghei ANKA (Pb-A) murine model. In vitro we tested the effect of anti-CD47 mAb on Plasmodium-infected RBC phagocytosis and found that anti-CD47 treatment significantly increased clearance of Plasmodium-infected RBCs. Infection of C57BL/6 mice with Pb-A is lethal and mice succumb to the clinical syndromes of CM between days 6 and 10 postinfection. Strikingly, treatment with anti-CD47 resulted in increased survival during the cerebral phase of Pb-A infection. Anti-CD47–treated mice had increased lymphocyte counts in the peripheral blood and increased circulating levels of IFN-γ, TNF-α, and IL-22. Despite increased circulating levels of inflammatory cytokines, anti-CD47–treated mice had reduced pathological features in the brain. Survival of ECM in anti-CD47–treated mice was correlated with reduced cellular accumulation in the cerebral vasculature, improved blood–brain barrier integrity, and reduced cytotoxic activity of infiltrating CD8+ T cells. These results demonstrate the therapeutic benefit of anti-CD47 to reduce morbidity in a lethal model of ECM, which may have implications for preventing mortality in young African children who are the highest casualties of CM.

In tropical areas of developing countries, the interactions among parasitic diseases such as soil-transmitted helminths (STHs) and malaria, and glucose-6-phosphate dehydrogenase deficiency (G6PDd), are complex. Here, we investigated their interactions and impact on anemia in school students residing in a conflict zone of northeast Myanmar. A cross-sectional survey was conducted between July and December 2015 in two schools located along the China-Myanmar border. Stool samples from the schoolchildren were analyzed for STH infections, whereas finger-prick blood samples were analyzed for G6PDd, hemoglobin concentrations, and Plasmodium infections. Among 988 enrolled children, Plasmodium vivax, Plasmodium falciparum, hookworm, Ascaris lumbricoides, and Trichuris trichiura infections occurred in 3.3%, 0.8%, 31.5%, 1.2%, and 0.3%, respectively. Glucose-6-phosphate dehydrogenase deficiency was present in 16.9% of the children, and there was a very high prevalence of anemia (73%). Anthropometric measures performed on all children showed that 50% of the children were stunted and 25% wasted. Moderate to severe anemia was associated with STH infections, stunting, and wasting. In addition, children had increasing odds of anemia with increasing burden of infections. This study revealed a high prevalence of G6PDd, STHs, and anemia in schools located in a conflict zone. In areas where malnutrition and STH infections are rampant, testing for both glucose-6-phosphate dehydrogenase and anemia should be considered before treating vivax malaria with 8-aminoquinolines.

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