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Acta Medica Indonesiana Jan 2023Plasmodium ovale consists of two subspecies - P. ovale wallikeri and P. ovale curtisi. Increased reports of imported malaria ovale in non-endemic regions and mixed...
Plasmodium ovale consists of two subspecies - P. ovale wallikeri and P. ovale curtisi. Increased reports of imported malaria ovale in non-endemic regions and mixed infection of P. ovale with other Plasmodium species suggest that P. ovale might be under-detected during routine surveillance. Areas endemic with P. ovale have mostly been reported in African and Western Pacific countries. A recent case report in Indonesia indicated that regions with P. ovale endemicity are not only distributed in Lesser Sunda and Papua, but also in North Sumatra.
Topics: Humans; Plasmodium ovale; Indonesia; Malaria; Coinfection
PubMed: 36999258
DOI: No ID Found -
Diagnostics (Basel, Switzerland) Oct 2021Nowadays, is divided into two non-recombinant sympatric species: and . In this mini review, we summarize the available knowledge on the clinical/biological aspects of... (Review)
Review
Nowadays, is divided into two non-recombinant sympatric species: and . In this mini review, we summarize the available knowledge on the clinical/biological aspects of spp. malaria and current techniques for the diagnosis/characterisation of and . infections are characterized by a deeper thrombocytopenia and shorter latency compared to infections, indicating that is more pathogenic than . Rapid diagnosis for effective management is difficult for spp., since specific rapid diagnostic tests are not available and microscopic diagnosis, which is recognized as the gold standard, requires expert microscopists to differentiate spp. from other species. Neglect in addressing these issues in the prevalence of spp. represents the existing gap in the fight against malaria.
PubMed: 34679597
DOI: 10.3390/diagnostics11101900 -
Journal of Microbiology, Immunology,... Oct 2017Plasmodium ovale is widely distributed in tropical countries, whereas it has not been reported in the Americas. It is not a problem globally because it is rarely... (Review)
Review
Plasmodium ovale is widely distributed in tropical countries, whereas it has not been reported in the Americas. It is not a problem globally because it is rarely detected by microscopy owing to low parasite density, which is a feature of clinical ovale malaria. P.o. curtisi and P.o. wallikeri are widespread in both Africa and Asia, and were known to be sympatric in many African countries and in southeast Asian countries. Small subunit ribosomal RNA (SSUrRNA) gene, cytochrome b (cytb) gene, and merozoite surface protein-1 (msp-1) gene were initially studied for molecular discrimination of P.o. curtisi and P.o. wallikeri using polymerase chain reaction (PCR) and DNA sequencing. DNA sequences of other genes from P. ovale in Southeast Asia and the southwestern Pacific regions were also targeted to differentiate the two sympatric types. In terms of clinical manifestations, P.o. wallikeri tended to produce higher parasitemia levels and more severe symptoms. To date, there have been a few studies that used the quantitative PCR method for discrimination of the two distinct P. ovale types. Conventional PCR with consequent DNA sequencing is the common method used to differentiate these two types. It is necessary to identify these two types because relapse periodicity, drug susceptibility, and mosquito species preference need to be studied to reduce ovale malaria. In this article, an easier method of molecular-level discrimination of P.o. curtisi and P.o. wallikeri is proposed.
Topics: Animals; Cytochromes b; DNA, Protozoan; Genes, Protozoan; Genes, rRNA; Humans; Malaria; Merozoite Surface Protein 1; Plasmodium ovale; Polymerase Chain Reaction; Protozoan Proteins; Sequence Analysis, DNA
PubMed: 28065415
DOI: 10.1016/j.jmii.2016.08.004 -
Trends in Parasitology Jun 2007Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still... (Review)
Review
Although Plasmodium malariae was first described as an infectious disease of humans by Golgi in 1886 and Plasmodium ovale identified by Stevens in 1922, there are still large gaps in our knowledge of the importance of these infections as causes of malaria in different parts of the world. They have traditionally been thought of as mild illnesses that are caused by rare and, in case of P. ovale, short-lived parasites. However, recent advances in sensitive PCR diagnosis are causing a re-evaluation of this assumption. Low-level infection seems to be common across malaria-endemic areas, often as complex mixed infections. The potential interactions of P. malariae and P. ovale with Plasmodium falciparum and Plasmodium vivax might explain some basic questions of malaria epidemiology, and understanding these interactions could have an important influence on the deployment of interventions such as malaria vaccines.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Humans; Infant; Infant, Newborn; Malaria; Microscopy; Plasmodium malariae; Plasmodium ovale; Polymerase Chain Reaction; Prevalence
PubMed: 17459775
DOI: 10.1016/j.pt.2007.04.009 -
Clinical Microbiology Reviews Jul 2005Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria... (Review)
Review
Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected Anopheles mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of > or = 101 degrees F and 4.5 fever episodes of > or = 104 degrees F. Mean maximum parasite levels were 6,944/microl for sporozoite-induced infections and 7,310/microl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and Saimiri monkeys following injection of sporozoites. Many different Anopheles species have been shown to be susceptible to infection with P. ovale, including A. gambiae, A. atroparvus, A. dirus, A. freeborni, A. albimanus, A. quadrimaculatus, A. stephensi, A. maculatus, A. subpictus, and A. farauti. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with P. ovale using a monoclonal antibody directed against the circumsporozoite protein. Plasmodium ovale is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of P. ovale is based primarily on the characteristics of the blood stages and its differentiation from P. vivax. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for P. ovale. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that P. ovale is closely related phylogenetically to any other of the primate malaria parasites that have been examined.
Topics: Animals; Anopheles; Humans; Insect Vectors; Malaria; Plasmodium ovale
PubMed: 16020691
DOI: 10.1128/CMR.18.3.570-581.2005 -
Malaria Journal May 2022During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data... (Review)
Review
During the twentieth century, there was an explosion in understanding of the malaria parasites infecting humans and wild primates. This was built on three main data sources: from detailed descriptive morphology, from observational histories of induced infections in captive primates, syphilis patients, prison inmates and volunteers, and from clinical and epidemiological studies in the field. All three were wholly dependent on parasitological information from blood-film microscopy, and The Primate Malarias" by Coatney and colleagues (1971) provides an overview of this knowledge available at that time. Here, 50 years on, a perspective from the third decade of the twenty-first century is presented on two pairs of primate malaria parasite species. Included is a near-exhaustive summary of the recent and current geographical distribution for each of these four species, and of the underlying molecular and genomic evidence for each. The important role of host transitions in the radiation of Plasmodium spp. is discussed, as are any implications for the desired elimination of all malaria species in human populations. Two important questions are posed, requiring further work on these often ignored taxa. Is Plasmodium brasilianum, circulating among wild simian hosts in the Americas, a distinct species from Plasmodium malariae? Can new insights into the genomic differences between Plasmodium ovale curtisi and Plasmodium ovale wallikeri be linked to any important differences in parasite morphology, cell biology or clinical and epidemiological features?
Topics: Animals; Genomics; Humans; Malaria; Parasites; Plasmodium malariae; Plasmodium ovale; Primates
PubMed: 35505317
DOI: 10.1186/s12936-022-04151-4 -
Parasites & Vectors Feb 2022Plasmodium ovale is a neglected malarial parasite that can form latent hypnozoites in the human liver. Over the last decade, molecular surveillance studies of...
BACKGROUND
Plasmodium ovale is a neglected malarial parasite that can form latent hypnozoites in the human liver. Over the last decade, molecular surveillance studies of non-falciparum malaria in Africa have highlighted that P. ovale is circulating below the radar, including areas where Plasmodium falciparum is in decline. To eliminate malaria where P. ovale is endemic, a better understanding of its epidemiology, asymptomatic carriage, and transmission biology is needed.
METHODS
We performed a pilot study on P. ovale transmission as part of an ongoing study of human-to-mosquito transmission of P. falciparum from asymptomatic carriers. To characterize the malaria asymptomatic reservoir, cross-sectional qPCR surveys were conducted in Bagamoyo, Tanzania, over three transmission seasons. Positive individuals were enrolled in transmission studies of P. falciparum using direct skin feeding assays (DFAs) with Anopheles gambiae s.s. (IFAKARA strain) mosquitoes. For a subset of participants who screened positive for P. ovale on the day of DFA, we incubated blood-fed mosquitoes for 14 days to assess sporozoite development.
RESULTS
Molecular surveillance of asymptomatic individuals revealed a P. ovale prevalence of 11% (300/2718), compared to 29% (780/2718) for P. falciparum. Prevalence for P. ovale was highest at the beginning of the long rainy season (15.5%, 128/826) in contrast to P. falciparum, which peaked later in both the long and short rainy seasons. Considering that these early-season P. ovale infections were low-density mono-infections (127/128), we speculate many were due to hypnozoite-induced relapse. Six of eight P. ovale-infected asymptomatic individuals who underwent DFAs successfully transmitted P. ovale parasites to A. gambiae.
CONCLUSIONS
Plasmodium ovale is circulating at 4-15% prevalence among asymptomatic individuals in coastal Tanzania, largely invisible to field diagnostics. A different seasonal peak from co-endemic P. falciparum, the capacity to relapse, and efficient transmission to Anopheles vectors likely contribute to its persistence amid control efforts focused on P. falciparum.
Topics: Animals; Anopheles; Cross-Sectional Studies; Humans; Malaria, Falciparum; Mosquito Vectors; Pilot Projects; Plasmodium falciparum; Plasmodium ovale; Prevalence; Tanzania
PubMed: 35164867
DOI: 10.1186/s13071-022-05181-2 -
The Indian Medical Gazette Nov 1932
PubMed: 29011039
DOI: No ID Found -
The Journal of Infectious Diseases Oct 2023Like Plasmodium vivax, both Plasmodium ovale curtisi and Plasmodium ovale wallikeri have the ability to cause relapse in humans, defined as recurring asexual parasitemia...
Like Plasmodium vivax, both Plasmodium ovale curtisi and Plasmodium ovale wallikeri have the ability to cause relapse in humans, defined as recurring asexual parasitemia originating from liver-dormant forms subsequent to a primary infection. Here, we investigated relapse patterns in P ovale wallikeri infections from a cohort of travelers who were exposed to the parasite in sub-Saharan Africa and then experienced relapses after their return to France. Using a novel set of 8 highly polymorphic microsatellite markers, we genotyped 15 P ovale wallikeri relapses. For most relapses, the paired primary and relapse infections were highly genetically related (with 12 being homologous), an observation that was confirmed by whole-genome sequencing for the 4 relapses we further studied. This is, to our knowledge, the first genetic evidence of relapses in P ovale spp.
Topics: Humans; Plasmodium ovale; Malaria; Plasmodium vivax; Recurrence; Microsatellite Repeats
PubMed: 37329228
DOI: 10.1093/infdis/jiad216