Artemisinin (ART) combination therapy is the main treatment for malaria. Pfk13 mutations (or K13 mutations, Kelch 13) are associated with ART resistance. This study aims to conduct a systematic review and meta-analysis of the prevalence of K13 mutations with ART resistance in malaria-endemic countries. An electronic search of studies in 2018 and a manual search in 2020 were performed to identify relevant studies. The risk of bias was assessed using the National Institutes of Health (NIH) quality assessment tool for observational cohort and cross-sectional studies. Data analysis was performed using R 4.1.0. Heterogeneity was estimated using the statistic I2 and Cochran Q test. A total of 170 studies were included in our review. Of these, 55 studies investigated the prevalence of K13 mutations in Southeast Asia. The meta-analysis showed that Southeast Asia had the highest prevalence of K13 mutations, whereas Africa, South America, Oceania, and other Asian countries outside Southeast Asia had a low prevalence of K13 mutations. The C580Y mutation was the most common in Southeast Asia with 35.5% (95%CI: 25.4-46.4%), whereas the dominant mutation in Africa was K189T (22.8%, 95%CI: 7.6-43.2%). This study revealed the emergence of ART resistance associated with K13 mutations in Southeast Asia. The diversity of each type of K13 mutation in other regions was also reported.

BACKGROUND: In sub-Saharan Africa (SSA), Plasmodium falciparum causes most of the malaria cases. Despite its crucial roles in disease severity and drug resistance, comprehensive data on Plasmodium falciparum genetic diversity and multiplicity of infection (MOI) are sparse in SSA. This study summarizes available information on genetic diversity and MOI, focusing on key markers (msp-1, msp-2, glurp, and microsatellites). The systematic review aimed to evaluate their influence on malaria transmission dynamics and offer insights for enhancing malaria control measures in SSA.
METHODS: The review was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Two reviewers conducted article screening, assessed the risk of bias (RoB), and performed data abstraction. Meta-analysis was performed using the random-effects model in STATA version 17.
RESULTS: The review included 52 articles: 39 cross-sectional studies and 13 Randomized Controlled Trial (RCT)/cohort studies, involving 11,640 genotyped parasite isolates from 23 SSA countries. The overall pooled mean expected heterozygosity was 0.65 (95% CI: 0.51-0.78). Regionally, values varied: East (0.58), Central (0.84), Southern (0.74), and West Africa (0.69). Overall pooled allele frequencies of msp-1 alleles K1, MAD20, and RO33 were 61%, 44%, and 40%, respectively, while msp-2 I/C 3D7 and FC27 alleles were 61% and 55%. Central Africa reported higher frequencies (K1: 74%, MAD20: 51%, RO33: 48%) than East Africa (K1: 46%, MAD20: 42%, RO33: 31%). For msp-2, East Africa had 60% and 55% for I/C 3D7 and FC27 alleles, while West Africa had 62% and 50%, respectively. The pooled allele frequency for glurp was 66%. The overall pooled mean MOI was 2.09 (95% CI: 1.88-2.30), with regional variations: East (2.05), Central (2.37), Southern (2.16), and West Africa (1.96). The overall prevalence of polyclonal Plasmodium falciparum infections was 63% (95% CI: 56-70), with regional prevalences as follows: East (62%), West (61%), Central (65%), and South Africa (71%).
CONCLUSIONS: The study shows substantial regional variation in Plasmodium falciparum parasite genetic diversity and MOI in SSA. These findings suggest a need for malaria control strategies and surveillance efforts considering regional-specific factors underlying Plasmodium falciparum infection.

Surveillance for genetic markers of resistance can provide valuable information on the likely efficacy of antimalarials but needs to be targeted to ensure optimal use of resources. We conducted a systematic search and review of publications in seven databases to compile resistance marker data from studies in India. The sample collection from the studies identified from this search was conducted between 1994 and 2020, and these studies were published between 1994 and 2022. In all, Plasmodium falciparum Kelch13 (PfK13), P. falciparum dihydropteroate synthase, and P. falciparum dihydrofolate reductase (PfDHPS) genotype data from 2,953, 4,148, and 4,222 blood samples from patients with laboratory-confirmed malaria, respectively, were extracted from these publications and uploaded onto the WorldWide Antimalarial Resistance Network molecular surveyors. These data were fed into hierarchical geostatistical models to produce maps with a predicted prevalence of the PfK13 and PfDHPS markers, and of the associated uncertainty. Zones with a predicted PfDHPS 540E prevalence of >15% were identified in central, eastern, and northeastern India. The predicted prevalence of PfK13 mutants was nonzero at only a few locations, but were within or adjacent to the zones with >15% prevalence of PfDHPS 540E. There may be a greater probability of artesunate-sulfadoxine-pyrimethamine failures in these regions, but these predictions need confirmation. This work can be applied in India and elsewhere to help identify the treatments most likely to be effective for malaria elimination.

Toxoplasmosis is a zoonotic disease with a worldwide prevalence that is caused by Toxoplasma gondii. This study aimed to summarize available data on genotyping T. gondii strains based on the GRA6 gene marker in different hosts around the world. We conducted a comprehensive literature search using five international databases (PubMed, Scopus, Science Direct, Web of Science, and Google Scholar) from inception until December 2021. We identified 32 papers eligible for inclusion in this systematic review. The majority of studies (50%) were carried out in Iran (n = 16) to identify T. gondii genotypes based on the GRA6 gene. Other countries with reported studies include China, Japan, Sweden, and Italy (n = 2 each). Out of 3,434 samples collected from various hosts, most studies (n = 11) focused on human samples (34.4%), followed by ovine (n = 7), pig (n = 4), goat (n = 3) and soil and cattle (n = 2).Using various molecular methods such as conventional PCR, nested-PCR, real-time PCR, microsatellite analysis, and Restriction Fragment Length Polymorphism (RFLP), we found DNA positive results in 805 out of 3,434 samples. Of these, 285 (35.40%), 207 (25.71%), 182 (22.60%), 65 (8.07%), and 18 (2.23%) were infected with types I, II, III, mix I, II, III, and mix II, III, respectively. Our data demonstrate that the GRA6 gene marker has sufficient polymorphism to detect three types of T. gondii genotypes in various hosts. Identifying the specific genotype could be valuable in developing new strategies for treatment, vaccination, diagnosis, control, and prevention of T. gondii infection.

UNASSIGNED: This review presents an overview of field findings on sequence variation of Plasmodium falciparum histidine-rich proteins 2/3 (PfHRP2/3) for which reference types (1-24) have been identified, and its critical impact on PfHRP2-based rapid diagnostic test (RDT) detection.
UNASSIGNED: This systematic review and meta-analysis was registered with PROSPERO, CRD42022316027, and conducted as per the PRISMA guidelines, and the methodological quality of studies was assessed.
UNASSIGNED: Of the 2184 records identified, 34 studies were included mostly from Africa (47.1%) and Asia (35.3%). The reference PfHRP2 types 1, 2, 3, 6, and 7 are invariably found at proportions ≥ 80-100% in all areas with the exception of The Americas where their proportion is very low. The proteins exhibited high diversity of variants/unknown types, especially for types 1, 2, 4, and 7. Eleven major PfHRP2 epitopes were found at pooled proportion > 90%. The existing models to predict RDT detection are greatly limited by the impact of factors such as low (very low) parasitemia, RDT brand, and PfHRP3 cross-reactivity. PfHRP2 length and presence/number of a given reference repeat type/variant did not seem to impact RDT detection.
UNASSIGNED: PfHRP2/3 are highly polymorphic and current findings are insufficient, conflicting and not convincing enough to conclude on the role of PfHRP2/3 sequence polymorphism in PfHRP2-based RDT detection.

Malaria still poses a major burden on human health around the world, especially in endemic areas. Plasmodium resistance to several antimalarial drugs has been one of the major hindrances in control of malaria. Thus, the World Health Organization recommended artemisinin-based combination therapy (ACT) as a front-line treatment for malaria. The emergence of parasites resistant to artemisinin, along with resistant to ACT partner drugs, has led to ACT treatment failure. The artemisinin resistance is mostly related to the mutations in the propeller domain of the kelch13 (k13) gene that encodes protein Kelch13 (K13). The K13 protein has an important role in parasite reaction to oxidative stress. The most widely spread mutation in K13, with the highest degree of resistance, is a C580Y mutation. Other mutations, which are already identified as markers of artemisinin resistance, are R539T, I543T, and Y493H. The objective of this review is to provide current molecular insights into artemisinin resistance in Plasmodium falciparum. The trending use of artemisinin beyond its antimalarial effect is described. Immediate challenges and future research directions are discussed. Better understanding of the molecular mechanisms underlying artemisinin resistance will accelerate implementation of scientific findings to solve problems with malarial infection.

China has now achieved the elimination of malaria, but it still faces severe challenges in the post-elimination stage. China continues to be plagued by imported malaria cases, and preventing re-transmission of imported malaria is critical. The effectiveness of antimalarial drugs for malaria control largely depends on the study of drug resistance markers in vitro. Monitoring molecular markers of parasite-associated drug resistance can help predict and manage drug resistance. There is currently a lack of systematic reviews of molecular markers for indigenous and imported malaria in China. Therefore, this review summarizes the published articles related to molecular marker polymorphism of indigenous and imported malaria cases in China in the past two decades, to study the mutation frequency and distribution of crt, mdr1, dhps, dhfr and K13 gene resistance-related loci. This can provide a whole picture of molecular markers and the resistance mutations of imported cases in China, which has certain significance for drug resistance surveillance planning, safe and effective treatment, and preventing the recurrence of local transmission by imported malaria in China in the future.

Malaria is an infectious disease transmitted by the female Anopheles mosquito and poses a severe threat to human health. At present, antimalarial drugs are the primary treatment for malaria. The widespread use of artemisinin-based combination therapies (ACTs) has dramatically reduced the number of malaria-related deaths; however, the emergence of resistance has the potential to reverse this progress. Accurate and timely diagnosis of drug-resistant strains of Plasmodium parasites via detecting molecular markers (such as Pfnhe1, Pfmrp, Pfcrt, Pfmdr1, Pfdhps, Pfdhfr, and Pfk13) is essential for malaria control and elimination. Here, we review the current techniques which commonly used for molecular diagnosis of antimalarial resistance in P. falciparum and discuss their sensitivities and specificities for different drug resistance-associated molecular markers, with the aim of providing insights into possible directions for future precise point-of-care testing (POCT) of antimalarial drug resistance of malaria parasites.

Toxoplasma gondii (T.gondii) is a widespread protozoan with significant economic losses and public health importance. But so far, the protective effect of reported DNA-based vaccines fluctuates widely, and no study has demonstrated complete protection.
This review provides an inclusive summary of T. gondii DNA vaccine antigens, adjuvants, and some other parameters. A total of 140 articles from 2000 to 2021 were collected from five databases. By contrasting the outcomes of acute and chronic challenges, we aimed to investigate and identify viable immunological strategies for optimum protection. Furthermore, we evaluated and discussed the impact of several parameters on challenge outcomes in the hopes of developing some recommendations to assist better future horizontal comparisons among research.
In the coming five years of research, the exploration of vaccine cocktails combining invasion antigens and metabolic antigens with genetic adjuvants or novel DNA delivery methods may offer us desirable protection against this multiple stage of life parasite. In addition to finding a better immune strategy, developing better in silico prediction methods, solving problems posed by variables in practical applications, and gaining a more profound knowledge of T.gondii-host molecular interaction is also crucial towards a successful vaccine.

Malaria remains the most common parasitic disease on the planet, with 229 million cases and 409,000 deaths worldwide in 2019, including 274,030 children under the age of 5. It is one of the most important infectious diseases in the world and its control is compromised by the spread of the parasite\'s resistance to antimalarial drugs. This study aims to review the literature of resistant Plasmodium falciparum genes over the past twenty years. One hundred and five (105) articles were collected and read while the resistance of P. falciparum was being studied. Several P. falciparum gene resistances antimalarial drugs were discovered over the past twenty years. The most recent one is the Kelch13 gene of P. falciparum (Pfkelch13) which has showed resistance to artemisinin in Asia. In Africa, this gene represents a potential candidate for resistance to artemisinin, although no resistance was reported.