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Scientific Reports Oct 2022Plasmodium knowlesi infections in Malaysia are a new threat to public health and to the national efforts on malaria elimination. In the Kapit division of Sarawak,...
Plasmodium knowlesi infections in Malaysia are a new threat to public health and to the national efforts on malaria elimination. In the Kapit division of Sarawak, Malaysian Borneo, two divergent P. knowlesi subpopulations (termed Cluster 1 and Cluster 2) infect humans and are associated with long-tailed macaque and pig-tailed macaque hosts, respectively. It has been suggested that forest-associated activities and environmental modifications trigger the increasing number of knowlesi malaria cases. Since there is a steady increase of P. knowlesi infections over the past decades in Sarawak, particularly in the Kapit division, we aimed to identify hotspots of knowlesi malaria cases and their association with forest activities at a geographical scale using the Geographic Information System (GIS) tool. A total of 1064 P. knowlesi infections from 2014 to 2019 in the Kapit and Song districts of the Kapit division were studied. Overall demographic data showed that males and those aged between 18 and 64 years old were the most frequently infected (64%), and 35% of infections involved farming activities. Thirty-nine percent of Cluster 1 infections were mainly related to farming surrounding residential areas while 40% of Cluster 2 infections were associated with activities in the deep forest. Average Nearest Neighbour (ANN) analysis showed that humans infected with both P. knowlesi subpopulations exhibited a clustering distribution pattern of infection. The Kernel Density Analysis (KDA) indicated that the hotspot of infections surrounding Kapit and Song towns were classified as high-risk areas for zoonotic malaria transmission. This study provides useful information for staff of the Sarawak State Vector-Borne Disease Control Programme in their efforts to control and prevent zoonotic malaria.
Topics: Adolescent; Adult; Animals; Borneo; Humans; Macaca fascicularis; Malaria; Malaysia; Male; Middle Aged; Plasmodium knowlesi; Young Adult
PubMed: 36241678
DOI: 10.1038/s41598-022-21439-2 -
Bio-protocol Feb 2020is a zoonotic malaria parasite in Southeast Asia that can cause severe and fatal malaria in humans. The main hosts are Macaques, but modern diagnostic tools reveal...
is a zoonotic malaria parasite in Southeast Asia that can cause severe and fatal malaria in humans. The main hosts are Macaques, but modern diagnostic tools reveal increasing numbers of human infections. After is the only other malaria parasite capable of being maintained in long term culture with human red blood cells (RBCs). Its closer ancestry to other non-falciparum human malaria parasites, more balanced AT-content, larger merozoites and higher transfection efficiencies, gives some key advantages over for the study of malaria parasite cell/molecular biology. Here, we describe the generation of marker-free CRISPR gene-edited parasites, the fast and scalable production of transfection constructs and analysis of transfection efficiencies. Our protocol allows rapid, reliable and unlimited rounds of genome editing in requiring only a single recyclable selection marker.
PubMed: 33654746
DOI: 10.21769/BioProtoc.3522 -
Tropical Parasitology 2020Malaria, a mosquito-transmitted parasitic disease, has been targeted for elimination in many parts of the world. For many years, and have been known to cause malaria... (Review)
Review
Malaria, a mosquito-transmitted parasitic disease, has been targeted for elimination in many parts of the world. For many years, and have been known to cause malaria in humans. Now, is considered to be an important cause of malaria, especially in Southeast Asia. The emergence of zoonotic implication is a challenge in the elimination efforts of malaria in Southeast Asia. is known to cause severe complicated malaria in humans. parasite is transmitted between humans and wild macaque through mosquito vectors. It appears that the malaria disease severity and host immune evasion depend on antigenic variation exhibited at the surface of the infected erythrocyte. is sensitive to antimalarial drug artemisinin. Identification of vector species, their biting behavior, timely correct diagnosis, and treatment are important steps in disease management and control. There is a need to identify and implement effective intervention measures to cut the chain of transmissions from animals to humans. The zoonotic malaria definitely poses a significant challenge in elimination and subsequent eradication of all types of malaria from this globe.
PubMed: 32775284
DOI: 10.4103/tp.TP_17_18 -
Therapeutic Advances in Infectious... 2021Malaria, a parasitic disease caused by protozoa belonging to the genus , continues to represent a formidable public health challenge. Despite being a preventable... (Review)
Review
Malaria, a parasitic disease caused by protozoa belonging to the genus , continues to represent a formidable public health challenge. Despite being a preventable disease, cases reported among travelers have continued to increase in recent decades. Protection of travelers against malaria, a potentially life-threatening disease, is of paramount importance, and it is therefore necessary for healthcare professionals to be up to date with the most recent recommendations. The present review provides an update of the existent measures for malaria prevention among travelers.
PubMed: 34484736
DOI: 10.1177/20499361211040690 -
Proceedings of the National Academy of... Nov 2021malaria parasites are obligate intracellular protozoans that use a unique form of locomotion, termed gliding motility, to move through host tissues and invade cells....
malaria parasites are obligate intracellular protozoans that use a unique form of locomotion, termed gliding motility, to move through host tissues and invade cells. The process is substrate dependent and powered by an actomyosin motor that drives the posterior translocation of extracellular adhesins which, in turn, propel the parasite forward. Gliding motility is essential for tissue translocation in the sporozoite and ookinete stages; however, the short-lived erythrocyte-invading merozoite stage has never been observed to undergo gliding movement. Here we show merozoites possess the ability to undergo gliding motility in vitro and that this mechanism is likely an important precursor step for successful parasite invasion. We demonstrate that two human infective species, and , have distinct merozoite motility profiles which may reflect distinct invasion strategies. Additionally, we develop and validate a higher throughput assay to evaluate the effects of genetic and pharmacological perturbations on both the molecular motor and the complex signaling cascade that regulates motility in merozoites. The discovery of merozoite motility provides a model to study the glideosome and adds a dimension for work aiming to develop treatments targeting the blood stage invasion pathways.
Topics: Actin Cytoskeleton; Actomyosin; Animals; Erythrocytes; Human Umbilical Vein Endothelial Cells; Humans; Inhibitory Concentration 50; Locomotion; Membrane Proteins; Merozoites; Plasmodium; Plasmodium falciparum; Protozoan Proteins; Signal Transduction; Sporozoites
PubMed: 34819379
DOI: 10.1073/pnas.2114442118 -
Tropical Medicine and Infectious Disease Aug 2022Despite the reduction in the number of cases of human malaria throughout the world, the incidence rate of knowlesi malaria is continuing to rise, especially in Southeast... (Review)
Review
Despite the reduction in the number of cases of human malaria throughout the world, the incidence rate of knowlesi malaria is continuing to rise, especially in Southeast Asia. The conventional strategies for the prevention and control of human malaria can provide some protection against knowlesi malaria. Despite the numerous studies on the risk factors and the innovative methods that may be used to prevent and control the vectors of the incidence rate remains high. An integrated approach that includes environmental intervention should be adopted in order to ensure the successful control of zoonotic malaria. A combination of personal-level protection, vector control and environmental control may mitigate the risk of transmission from macaques to humans and, ultimately, reduce the incidence rate of knowlesi malaria.
PubMed: 36006270
DOI: 10.3390/tropicalmed7080178 -
Journal of Microbiology, Immunology,... Oct 2019Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east... (Review)
Review
Plasmodium knowlesi is now regarded as the fifth malaria parasite causing human malaria as it is widely distributed in South-East Asian countries especially east Malaysia where two Malaysian states namely Sabah and Sarawak are situated. In 2004, Polymerase Chain Reaction (PCR) was applied for diagnosing knowlesi malaria in the Kapit Division of Sarawak, Malaysia, so that human P. knowlesi infections could be detected correctly while blood film microscopy diagnosed incorrectly as Plasmodium malariae. This parasite is transmitted from simian hosts to humans via Anopheles vectors. Indonesia is the another country in South East Asia where knowlesi malaria is moderately prevalent. In the last decade, Sarawak and Sabah, the two states of east Malaysia became the target of P. knowlesi research due to prevalence of cases with occasional fatal infections. The host species of P. knowlesi are three macaque species namely Macaca fascicularis, Macaca nemestrina and Macaca leonina while the vector species are the Leucosphyrus Complex and the Dirus Complex of the Leucophyrus Group of Anopheles mosquitoes. Rapid diagnostic tests (RDT) are non-existent for knowlesi malaria although timely treatment is necessary for preventing complications, fatality and drug resistance. Development of RDT is essential in dealing with P. knowlesi infections in poor rural healthcare services. Genetic studies of the parasite on possibility of human-to-human transmission of P. knowlesi were recommended for further studies.
Topics: Animals; Anopheles; Asia, Southeastern; Diagnostic Tests, Routine; Humans; Insect Vectors; Macaca fascicularis; Malaria; Malaysia; Monkey Diseases; Plasmodium knowlesi; Polymerase Chain Reaction; Prevalence; Rural Health
PubMed: 31320238
DOI: 10.1016/j.jmii.2019.05.012 -
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 -
Advances in Parasitology 2021Within the past two decades, incidence of human cases of the zoonotic malaria Plasmodium knowlesi has increased markedly. P. knowlesi is now the most common cause of... (Review)
Review
Within the past two decades, incidence of human cases of the zoonotic malaria Plasmodium knowlesi has increased markedly. P. knowlesi is now the most common cause of human malaria in Malaysia and threatens to undermine malaria control programmes across Southeast Asia. The emergence of zoonotic malaria corresponds to a period of rapid deforestation within this region. These environmental changes impact the distribution and behaviour of the simian hosts, mosquito vector species and human populations, creating new opportunities for P. knowlesi transmission. Here, we review how landscape changes can drive zoonotic disease emergence, examine the extent and causes of these changes across Southeast and identify how these mechanisms may be impacting P. knowlesi dynamics. We review the current spatial epidemiology of reported P. knowlesi infections in people and assess how these demographic and environmental changes may lead to changes in transmission patterns. Finally, we identify opportunities to improve P. knowlesi surveillance and develop targeted ecological interventions within these landscapes.
Topics: Animals; Asia, Southeastern; Humans; Malaria; Malaysia; Plasmodium knowlesi; Zoonoses
PubMed: 34620384
DOI: 10.1016/bs.apar.2021.08.006 -
Briefings in Functional Genomics Sep 2019Two simian malaria parasite species, Plasmodium knowlesi and Plasmodium cynomolgi, cause zoonotic infections in Southeast Asia, and they have therefore gained... (Review)
Review
Two simian malaria parasite species, Plasmodium knowlesi and Plasmodium cynomolgi, cause zoonotic infections in Southeast Asia, and they have therefore gained recognition among scientists and public health officials. Notwithstanding, these species and others including Plasmodium coatneyi have served for decades as sources of knowledge on the biology, genetics and evolution of Plasmodium, and the diverse ramifications and outcomes of malaria in their monkey hosts. Experimental analysis of these species can help to fill gaps in knowledge beyond what may be possible studying the human malaria parasites or rodent parasite species. The genome sequences for these simian malaria parasite species were reported during the last decade, and functional genomics research has since been pursued. Here research on the functional genomics analysis involving these species is summarized and their importance is stressed, particularly for understanding host-parasite interactions, and potentially testing novel interventions. Importantly, while Plasmodium falciparum and Plasmodium vivax can be studied in small New World monkeys, the simian malaria parasites can be studied more effectively in the larger Old World monkey macaque hosts, which are more closely related to humans. In addition to ex vivo analyses, experimental scenarios can include passage through Anopheline mosquito hosts and longitudinal infections in monkeys to study acute and chronic infections, as well as relapses, all in the context of the in vivo host environment. Such experiments provide opportunities for understanding functional genomic elements that govern host-parasite interactions, immunity and pathogenesis in-depth, addressing hypotheses not possible from in vitro cultures or cross-sectional clinical studies with humans.
Topics: Animals; Genomics; Host-Parasite Interactions; Humans; Plasmodium; Plasmodium cynomolgi; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Primates; Systems Biology
PubMed: 31241151
DOI: 10.1093/bfgp/elz013