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Tropical Medicine and Infectious Disease Oct 2023() causes zoonotic malaria and is known as the "fifth human malaria parasite". malaria is an emerging threat because infections are increasing and can be fatal. While... (Review)
Review
() causes zoonotic malaria and is known as the "fifth human malaria parasite". malaria is an emerging threat because infections are increasing and can be fatal. While most infections are in Southeast Asia (SEA), especially Malaysia, travelers frequently visit this region and can present with malaria around the world. So, clinicians need to know (1) patients who present with fever after recent travel to SEA might be infected with and (2) is often misdiagnosed as (which typically causes less severe malaria). Here we review the history, pathophysiology, clinical features, diagnosis, and treatment of malaria. Severe disease is most common in adults. Signs and symptoms can include fever, abdominal pain, jaundice, acute kidney injury, acute respiratory distress syndrome, hyponatremia, hyperparasitemia, and thrombocytopenia. Dengue is one of the diseases to be considered in the differential. Regarding pathophysiologic mechanisms, when parasites invade mature red blood cells (RBCs, i.e., normocytes) and reticulocytes, changes in the red blood cell (RBC) surface can result in life-threatening cytoadherence, sequestration, and reduced RBC deformability. Since molecular mechanisms involving the erythrocytic stage are responsible for onset of severe disease and lethal outcomes, it is biologically plausible that manual exchange transfusion (ET) or automated RBC exchange (RBCX) could be highly beneficial by replacing "sticky" parasitized RBCs with uninfected, deformable, healthy donor RBCs. Here we suggest use of special -resistant donor RBCs to optimize adjunctive manual ET/RBCX for malaria. "Therapeutically-rational exchange transfusion" (T-REX) is proposed in which -resistant RBCs are transfused (instead of disease-promoting RBCs). Because expression of the Duffy antigen on the surface of human RBCs is essential for parasite invasion, T-REX of Duffy-negative RBCs-also known as Fy(a-b-) RBCs-could replace the majority of the patient's circulating normocytes with invasion-resistant RBCs (in a single procedure lasting about 2 h). When sequestered or non-sequestered iRBCs rupture-in a 24 h asexual life cycle-the released merozoites cannot invade Fy(a-b-) RBCs. When Fy(a-b-) RBC units are scarce (e.g., in Malaysia), clinicians can consider the risks and benefits of transfusing plausibly -resistant RBCs, such as glucose-6-phosphate dehydrogenase deficient (G6PDd) RBCs and Southeast Asian ovalocytes (SAO). Patients typically require a very short recovery time (<1 h) after the procedure. Fy(a-b-) RBCs should have a normal lifespan, while SAO and G6PDd RBCs may have mildly reduced half-lives. Because SAO and G6PDd RBCs come from screened blood donors who are healthy and not anemic, these RBCs have a low-risk for hemolysis and do not need to be removed after the patient recovers from malaria. T-REX could be especially useful if (1) antimalarial medications are not readily available, (2) patients are likely to progress to severe disease, or (3) drug-resistant strains emerge. In conclusion, T-REX is a proposed optimization of manual ET/RBCX that has not yet been utilized but can be considered by physicians to treat malaria patients.
PubMed: 37888606
DOI: 10.3390/tropicalmed8100478 -
Malaria Journal Oct 2023
PubMed: 37880730
DOI: 10.1186/s12936-023-04733-w -
Malaria Journal Oct 2023
PubMed: 37858164
DOI: 10.1186/s12936-023-04732-x -
Frontiers in Public Health 2023The provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and...
INTRODUCTION
The provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and preventing re-transmission of imported malaria. The study aimed to evaluate the detection capability of malaria diagnosis in China from 2014 to 2021.
METHODS
Data on malaria cases reported in the provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, Guangxi, and Zhejiang from 2014 to 2021 were collected and analyzed.
RESULTS
In total, 5,770 malaria cases were reported from 2014 to 2021, and 99.05% (5,715/5,770) were submitted to the provincial malaria diagnosis reference laboratories. The median time between malaria cases being reported and the samples being received by reference laboratories was 6 days (Interquartile range, IQR:3-12 days) from 2017 to 2021. Diagnosis of 5,680 samples in the laboratory were confirmed by provincial reference laboratories, including 3,970 cases of , 414 of , 1,055 of , 158 of , 1 of , and 82 of mixed infections. species of 5,141 confirmed cases were consistent with the initial diagnosis, with a species accuracy rate of 90.53% (5,141/5,679). The accuracy of diagnosis in health facilities was higher than that of non-falciparum species. The inconsistency between microscopy and nested polymerase chain reaction (nPCR) results of confirmatory diagnosis was mainly in malaria-positive versus malaria-negative cases, as well as in mixed versus single infection cases.
CONCLUSION
The provincial malaria diagnosis reference laboratories have played an important role in ensuring the accuracy and reliability of diagnosis in health facilities. However, the results of this study imply that capacity training for the identification of species in health facilities is warranted.
Topics: Humans; Laboratories; Reproducibility of Results; China; Malaria; Plasmodium
PubMed: 37841716
DOI: 10.3389/fpubh.2023.1243642 -
Proceedings (Baylor University. Medical... 2023is a genus of parasites that comprises different species. The species and are known to cause a vector-borne illness called malaria, and among these, is known to... (Review)
Review
is a genus of parasites that comprises different species. The species and are known to cause a vector-borne illness called malaria, and among these, is known to cause major complications. The vector, the Anopheles mosquito, is commonly found in warmer regions close to the equator, and hence transmission and numbers of cases tend to be higher in Sub-Saharan Africa, South Asia, and Central America. The number of cases of malaria in the United States has remained stable over the years with low transmission rates, and the disease is mostly seen in the population with a recent travel history to endemic regions. The main reason behind this besides the weather conditions is that economically developed countries have eliminated mosquitos. However, there have been reports of locally reported cases with in areas such as Florida and Texas in patients with no known travel history. This paper aims to familiarize US physicians with the pathophysiology, clinical features, and diagnostic modalities of malaria, as well as available treatment options.
PubMed: 37829240
DOI: 10.1080/08998280.2023.2255514 -
Spatial analyses of Plasmodium knowlesi vectors with reference to control interventions in Malaysia.Parasites & Vectors Oct 2023Malaria parasites such as Plasmodium knowlesi, P. inui, and P. cynomolgi are spread from macaques to humans through the Leucosphyrus Group of Anopheles mosquitoes. It is...
BACKGROUND
Malaria parasites such as Plasmodium knowlesi, P. inui, and P. cynomolgi are spread from macaques to humans through the Leucosphyrus Group of Anopheles mosquitoes. It is crucial to know the distribution of these vectors to implement effective control measures for malaria elimination. Plasmodium knowlesi is the most predominant zoonotic malaria parasite infecting humans in Malaysia.
METHODS
Vector data from various sources were used to create distribution maps from 1957 to 2021. A predictive statistical model utilizing logistic regression was developed using significant environmental factors. Interpolation maps were created using the inverse distance weighted (IDW) method and overlaid with the corresponding environmental variables.
RESULTS
Based on the IDW analysis, high vector abundances were found in the southwestern part of Sarawak, the northern region of Pahang and the northwestern part of Sabah. However, most parts of Johor, Sabah, Perlis, Penang, Kelantan and Terengganu had low vector abundance. The accuracy test indicated that the model predicted sampling and non-sampling areas with 75.3% overall accuracy. The selected environmental variables were entered into the regression model based on their significant values. In addition to the presence of water bodies, elevation, temperature, forest loss and forest cover were included in the final model since these were significantly correlated. Anopheles mosquitoes were mainly distributed in Peninsular Malaysia (Titiwangsa range, central and northern parts), Sabah (Kudat, West Coast, Interior and Tawau division) and Sarawak (Kapit, Miri, and Limbang). The predicted Anopheles mosquito density was lower in the southern part of Peninsular Malaysia, the Sandakan Division of Sabah and the western region of Sarawak.
CONCLUSION
The study offers insight into the distribution of the Leucosphyrus Group of Anopheles mosquitoes in Malaysia. Additionally, the accompanying predictive vector map correlates well with cases of P. knowlesi malaria. This research is crucial in informing and supporting future efforts by healthcare professionals to develop effective malaria control interventions.
Topics: Humans; Animals; Malaysia; Plasmodium knowlesi; Mosquito Vectors; Malaria; Macaca; Anopheles; Spatial Analysis
PubMed: 37814287
DOI: 10.1186/s13071-023-05984-x -
Malaria Journal Oct 2023Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that...
BACKGROUND
Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that the pandemic might erode the success of malaria control as there are reports of increase malaria cases in resource limited countries. Little is known how the COVID-19 pandemic has impacted malaria in middle-income countries like Malaysia. Here the public health response to a Plasmodium malariae outbreak occurred in a village in Sabah state, Malaysia, during a COVID-19 movement control order is reported.
METHODS
An outbreak was declared following the detection of P. malariae in July 2020 and active case detection for malaria was performed by collecting blood samples from residents residing within 2 km radius of Moyog village. Vector prevalence and the efficacy of residual insecticides were determined. Health awareness programmes were implemented to prevent future outbreaks. A survey was conducted among villagers to understand risk behaviour and beliefs concerning malaria.
RESULTS
A total of 5254 blood samples collected from 19 villages. Among them, 19 P. malariae cases were identified, including the index case, which originated from a man who returned from Indonesia. His return from Indonesia and healthcare facilities visit coincided with the movement control order during COVID-19 pandemic when the healthcare facilities stretched its capacity and only serious cases were given priority. Despite the index case being a returnee from a malaria endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. All cases were symptomatic and uncomplicated except for a pregnant woman with severe malaria. There were no deaths; all patients recovered following treatment with artemether-lumefantrine combination therapy. Anopheles balabacensis and Anopheles barbirostris were detected in ponds, puddles and riverbeds. The survey revealed that fishing and hunting during night, and self-treatment for mild symptoms contributed to the outbreak. Despite the index case being a returnee from a malaria-endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities.
CONCLUSION
The outbreak occurred during a COVID-19 movement control order, which strained healthcare facilities, prioritizing only serious cases. Healthcare workers need to be more aware of the risk of malaria from individuals who return from malaria endemic areas. To achieve malaria elimination and prevention of disease reintroduction, new strategies that include multisectoral agencies and active community participation are essential for a more sustainable malaria control programme.
Topics: Male; Animals; Female; Humans; Malaysia; Plasmodium malariae; Antimalarials; Public Health; Pandemics; Mosquito Vectors; Plasmodium knowlesi; Artemether; Artemether, Lumefantrine Drug Combination; COVID-19; Malaria; Disease Outbreaks; Anopheles
PubMed: 37789320
DOI: 10.1186/s12936-023-04693-1 -
The American Journal of Tropical... Nov 2023Malaysia has maintained zero cases of indigenous human malaria since 2018. However, zoonotic malaria is still prevalent in underdeveloped areas and hard-to-reach...
Malaysia has maintained zero cases of indigenous human malaria since 2018. However, zoonotic malaria is still prevalent in underdeveloped areas and hard-to-reach populations. This study aimed to determine the prevalence of malaria among remote indigenous communities in Peninsular Malaysia. A cross-sectional survey was conducted in six settlements in Kelantan state, from June to October 2019. Blood samples were tested for malaria using microscopy and nested polymerase chain reaction (nPCR) targeting the Plasmodium cytochrome c oxidase subunit III (cox3) gene. Of the 1,954 individuals who appeared healthy, no malaria parasites were found using microscopy. However, nPCR revealed seven cases of Plasmodium knowlesi mono-infection (0.4%), and six out of seven infections were in the group of 19 to 40 years old (P = 0.026). No human malaria species were detected by nPCR. Analysis of the DNA sequences also showed high similarity that reflects common ancestry to other P. knowlesi isolates. These findings indicate low submicroscopic P. knowlesi infections among indigenous communities in Malaysia, requiring PCR-based surveillance to support malaria control activities in the country.
Topics: Humans; Young Adult; Adult; Plasmodium knowlesi; Malaysia; Cross-Sectional Studies; Malaria; Polymerase Chain Reaction
PubMed: 37748768
DOI: 10.4269/ajtmh.23-0184 -
Emerging Infectious Diseases Oct 2023A 55-year-old man sought treatment for an uncomplicated febrile illness after returning to Canada from the Philippines. A suspected diagnosis of Plasmodium knowlesi... (Review)
Review
A 55-year-old man sought treatment for an uncomplicated febrile illness after returning to Canada from the Philippines. A suspected diagnosis of Plasmodium knowlesi infection was confirmed by PCR, and treatment with atovaquone/proguanil brought successful recovery. We review the evolving epidemiology of P. knowlesi malaria in the Philippines, specifically within Palawan Island.
Topics: Male; Humans; Middle Aged; Philippines; Plasmodium knowlesi; Malaria; Canada; Polymerase Chain Reaction
PubMed: 37735805
DOI: 10.3201/eid2910.230809 -
Nature Communications Sep 2023Tryptophan Rich Antigens (TRAgs) are encoded by a multi-gene family found in all Plasmodium species, but are significantly expanded in P. vivax and closely related...
Tryptophan Rich Antigens (TRAgs) are encoded by a multi-gene family found in all Plasmodium species, but are significantly expanded in P. vivax and closely related parasites. We show that multiple P. vivax TRAgs are expressed on the merozoite surface and that one, PVP01_0000100 binds red blood cells with a strong preference for reticulocytes. Using X-ray crystallography, we solved the structure of the PVP01_0000100 C-terminal tryptophan rich domain, which defines the TRAg family, revealing a three-helical bundle that is conserved across Plasmodium and has structural homology with lipid-binding BAR domains involved in membrane remodelling. Biochemical assays confirm that the PVP01_0000100 C-terminal domain has lipid binding activity with preference for sulfatide, a glycosphingolipid present in the outer leaflet of plasma membranes. Deletion of the putative orthologue in P. knowlesi, PKNH_1300500, impacts invasion in reticulocytes, suggesting a role during this essential process. Together, this work defines an emerging molecular function for the Plasmodium TRAg family.
Topics: Humans; Plasmodium vivax; Tryptophan; Plasmodium; Antigens, Protozoan; Malaria, Vivax; Sulfoglycosphingolipids
PubMed: 37709739
DOI: 10.1038/s41467-023-40885-8