Persistently elevated laboratory markers of thrombosis and fibrinolysis after clinical recovery in malaria points to residual and smouldering cellular damage

Alteration of prothrombin time in Plasmodium falciparum and Plasmodium vivax infections with different levels of severity: a systematic review and meta-analysis

Malaria infection leads to hematological abnormalities, including deranged prothrombin time (PT). Given the inconsistent findings regarding PT in malaria across different severities and between Plasmodium falciparum and P. vivax, this study aimed to synthesize available evidence on PT variations in clinical malaria. A systematic literature search was performed in PubMed, Embase, Scopus, Ovid, and Medline from 27 November 2021 to 2 March 2023 to obtain studies documenting PT in malaria. Study quality was evaluated using the Joanna Briggs Institute checklist, with data synthesized through both qualitative and quantitative methods, including meta-regression and subgroup analyses, to explore heterogeneity and publication bias. From 2767 articles, 21 studies were included. Most studies reported prolonged or increased PT in malaria patients compared to controls, a finding substantiated by the meta-analysis (P < 0.01, Mean difference: 8.86 s, 95% CI 5.32-12.40 s, I2: 87.88%, 4 studies). Severe malaria cases also showed significantly higher PT than non-severe ones (P = 0.03, Hedges's g: 1.65, 95% CI 0.20-3.10, I2: 97.91%, 7 studies). No significant PT difference was observed between P. falciparum and P. vivax infections (P = 0.88, Mean difference: 0.06, 95% CI - 0.691-0.8, I2: 65.09%, 2 studies). The relationship between PT and malaria-related mortality remains unclear, underscoring the need for further studies. PT is typically prolonged or increased in malaria, particularly in severe cases, with no notable difference between P. falciparum and P. vivax infections. The inconsistency in PT findings between fatal and non-fatal cases highlights a gap in current understanding, emphasizing the need for future studies to inform therapeutic strategies.

SARS-CoV-2 and Plasmodium falciparum common immunodominant regions may explain low COVID-19 incidence in the malaria-endemic belt

Coronavirus disease 2019 (COVID-19) has caused significant morbidity and mortality and new cases are on the rise globally, yet malaria-endemic areas report statistically significant lower incidences. We identified potential shared targets for an immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by immune determinants' shared identities with P. falciparum using the Immune Epitope Database and Analysis Resource Immune 9.0 browser tool. Probable cross-reactivity is suggested through HLA-A∗02:01 and subsequent CD8+ T-cell activation. The apparent immunodominant epitope conservation between SARS-CoV-2 (N and open reading frame (ORF) 1ab) and P. falciparum thrombospondin-related anonymous protein (TRAP) may underlie the low COVID-19 incidence in the malaria-endemic zone by providing immunity against virus infection to those previously infected with Plasmodium. Additionally, we hypothesize that the shared epitopes which lie within antigens that aid in the establishment of the P. falciparum erythrocyte invasion may be an alternative route for SARS-CoV-2 via the erythrocyte CD147 receptor, although this remains to be proven.

D-dimer levels in non-immune travelers with malaria

BACKGROUND

Elevated serum D-dimer levels may reflect endothelial activation, which in malaria may correlate with parasite biomass and disease severity.

METHODS

We performed a retrospective chart review of all non-immune travelers hospitalized with malaria during 01/2000-12/2014 at the Sheba Medical Center, Israel. Admission and peak D-dimer levels were compared among malaria patients, according to Plasmodium species and severity.

RESULTS

Complete laboratory data was available for 94/168 travelers hospitalized with malaria, with 68.1% caused by P. falciparum. Admission D-dimer levels were significantly higher in P. falciparum malaria compared to non-falciparum malaria cases (3585 ± 7045 and 802 ± 1248 ng/dL respectively, p = 0.04). Admission D-dimer levels were higher in patients with severe compared to non-severe P. falciparum malaria (4058 ± 3544 & 3490 ± 7549 ng/dL), however the difference was short of statistical significance (P = 0.06). Peak D-dimer levels were also significantly higher in severe and non-severe P. falciparum than in non-falciparum cases.

CONCLUSIONS

In most non-immune travelers with malaria, D-dimer levels are elevated, are higher in P. falciparum malaria compared to non-falciparum malaria, and appear to increase with disease severity, probably reflecting the level of endothelial damage.

Malaria and vascular endothelium

Involvement of the cardiovascular system in patients with infectious and parasitic diseases can result from both intrinsic mechanisms of the disease and drug intervention. Malaria is an example, considering that the endothelial injury by Plasmodium-infected erythrocytes can cause circulatory disorders. This is a literature review aimed at discussing the relationship between malaria and endothelial impairment, especially its effects on the cardiovascular system. We discuss the implications of endothelial aggression and the interdisciplinarity that should guide the malaria patient care, whose acute infection can contribute to precipitate or aggravate a preexisting heart disease.