DOCSLIB.ORG

CYCLE 43 SLIDE 1 Plasmodium Ovale

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
CYCLE 43 SLIDE 1 Plasmodium Ovale P.O. Box 131375, Bryanston, 2074 Ground Floor, Block 5 Bryanston Gate, 170 Curzon Road Bryanston, Johannesburg, South Africa 804 Flatrock, Buiten Street, Cape Town, 8001 www.thistle.co.za Tel: +27 (011) 463 3260 Fax: +27 (011) 463 3036 Fax to Email: + 27 (0) 86-557-2232 e-mail : [email protected] Please read this section first The HPCSA and the Med Tech Society have confirmed that this clinical case study, plus your routine review of your EQA reports from Thistle QA, should be documented as a “Journal Club” activity. This means that you must record those attending for CEU purposes. Thistle will not issue a certificate to cover these activities, nor send out “correct” answers to the CEU questions at the end of this case study. The Thistle QA CEU No is: MT-13/00142. Each attendee should claim THREE CEU points for completing this Quality Control Journal Club exercise, and retain a copy of the relevant Thistle QA Participation Certificate as proof of registration on a Thistle QA EQA. DIFFERENTIAL SLIDES LEGEND CYCLE 43 SLIDE 1 Plasmodium ovale Plasmodium ovale is a species of parasitic protozoa that causes tertian malaria in humans. It is closely related to Plasmodium falciparum and Plasmodium vivax, which are responsible for most malaria. It is rare compared to these two parasites, and substantially less dangerous than P. falciparum. P. ovale has recently been shown by genetic methods to consist of two subspecies, P. ovale curtisi and P. ovale wallikeri. History This species was first described by Stephens in a patient from East Africa in 1922. Epidemiology While it is frequently said that P. ovale is very limited in its range being limited to West Africa, the Philippines, eastern Indonesia, and Papua New Guinea, it has been reported from Bangladesh, Cambodia, India, Thailand and Vietnam. The reported prevalence is low (<5%) with the exception of West Africa, where prevalence above 10% have been observed. The epidemiology of this parasite is in need of updating because the most recent global map of its distribution was produced in 1969. It has been estimated that there are about 15 million cases of infection each year with this parasite. Clinical features The pre-patent 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 Diagnosis The microscopic appearance of P. ovale is very similar to that of P. vivax and if there are only a small number of parasites seen, it may be impossible to distinguish the two species on morphological grounds alone. There is no difference between the medical treatment of P. ovale and P. vivax, and therefore some laboratory diagnoses report "P. vivax/ovale", which is perfectly Thistle QA is a SANAS accredited organisation, No: PTS0001 Accredited to ISO 17043 Certificate available on request or at www.sanas.co.za Page 1 of 3 P.O. Box 131375, Bryanston, 2074 Ground Floor, Block 5 Bryanston Gate, 170 Curzon Road Bryanston, Johannesburg, South Africa 804 Flatrock, Buiten Street, Cape Town, 8001 www.thistle.co.za Tel: +27 (011) 463 3260 Fax: +27 (011) 463 3036 Fax to Email: + 27 (0) 86-557-2232 e-mail : [email protected] acceptable as treatment for the two are very similar. Schüffner's dots are seen on the surface of the parasitised red blood cell, but these are larger and darker than in P. vivax and are sometimes called James' dots or James' stippling. About twenty percent of the parasitised cells are oval in shape (hence the species name) and some of the oval cells also have fimbriated edges (the so-called "comet cell"). The mature schizonts of P. ovale never have more than twelve nuclei within them and this is the only reliable way of distinguishing between the two species. P. vivax and P. ovale that has been sitting in EDTA for more than half-an-hour before the blood film is made will look very similar in appearance to P. malariae, which is an important reason to warn the laboratory immediately when the blood sample is drawn so they can process the sample as soon as it arrives. While similar to P. vivax, P. ovale is able to infect individuals who are negative for the Duffy blood group, which is the case for many residents of sub Saharan Africa. This explains the greater prevalence of P. ovale (rather than P. vivax) in most of Africa. P. ovale gametocytes are round to oval with large nuclei P. ovale schizonts have 6 to 14 merozoites, clustered and may almost fill the red blood cells. Pigment is brown around a mass of dark-brown pigment. and more coarse in comparison to P. vivax. In P. ovale infections, red blood cells can be normal or slightly enlarged (up to 1 1/4×) in size, may be round to oval, and are sometimes fimbriated. Under optimal conditions, Schüffner's dots may be seen in Giemsa stained slides. Treatment Standard treatment is concurrent treatment with chloroquine and primaquine. The combination atovaquone-proguanil may be used in those patients who are unable to take chloroquine for whatever reason. Thistle QA is a SANAS accredited organisation, No: PTS0001 Accredited to ISO 17043 Certificate available on request or at www.sanas.co.za Page 2 of 3 P.O. Box 131375, Bryanston, 2074 Ground Floor, Block 5 Bryanston Gate, 170 Curzon Road Bryanston, Johannesburg, South Africa 804 Flatrock, Buiten Street, Cape Town, 8001 www.thistle.co.za Tel: +27 (011) 463 3260 Fax: +27 (011) 463 3036 Fax to Email: + 27 (0) 86-557-2232 e-mail : [email protected] Life Cycle Human Infection Liver Stage The P. ovale sporozoite enters a hepatocyte and begins its exoerythrocytic schizogony stage. This is characterized by multiple rounds of nuclear division without cellular segmentation. After a certain number of nuclear divisions, the parasite cell will segment and merozoites are formed. There are situations where some of the sporozoites do not immediately start to grow and divide after entering the hepatocyte, but remain in a dormant, hypnozoite stage for weeks or months. The duration of latency is variable from one hypnozoite to another and the factors that will eventually trigger growth are not known; this explains how a single infection can be responsible for a series of waves of parasitaemia or "relapses". References 1. http://www.dpd.cdc.gov/dpdx/HTML/PDF_Files/Povale_benchaidV2.pdf 2. http://en.wikipedia.org/wiki/Plasmodium_ovale Questions 1. Discuss the clinical features of Plasmodium ovale. 2. Discuss the lab findings in a patient diagnosed Plasmodium ovale. 3. Discuss the life cycle of Plasmodium ovale. Thistle QA is a SANAS accredited organisation, No: PTS0001 Accredited to ISO 17043 Certificate available on request or at www.sanas.co.za Page 3 of 3 .
Load more

Recommended publications
  • Plasmodium Evasion of Mosquito Immunity and Global Malaria Transmission: the Lock-And-Key Theory
    Plasmodium evasion of mosquito immunity and global malaria transmission: The lock-and-key theory Alvaro Molina-Cruz1,2, Gaspar E. Canepa1, Nitin Kamath, Noelle V. Pavlovic, Jianbing Mu, Urvashi N. Ramphul, Jose Luis Ramirez, and Carolina Barillas-Mury2 Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852 Contributed by Carolina Barillas-Mury, October 15, 2015 (sent for review September 19, 2015; reviewed by Serap Aksoy and Daniel L. Hartl) Plasmodium falciparum malaria originated in Africa and became for the parasite to evade mosquito immunity. The implications global as humans migrated to other continents. During this jour- of P. falciparum selection by mosquitoes for global malaria ney, parasites encountered new mosquito species, some of them transmission are discussed. evolutionarily distant from African vectors. We have previously shown that the Pfs47 protein allows the parasite to evade the mos- Results quito immune system of Anopheles gambiae mosquitoes. Here, we Differences in Compatibility Between P. falciparum Isolates from investigated the role of Pfs47-mediated immune evasion in the Diverse Geographic Origin and Different Anopheline Species. The adaptation of P. falciparum to evolutionarily distant mosquito species. compatibility between P. falciparum isolates from different continents We found that P. falciparum isolates from Africa, Asia, or the Americas and mosquito vectors that are geographically and evolutionarily have low compatibility to malaria vectors from a different continent, distant was investigated by simultaneously infecting major malaria an effect that is mediated by the mosquito immune system. We iden- vectors from Africa (A. gambiae), Southeast Asia (Anopheles dirus), tified 42 different haplotypes of Pfs47 that have a strong geographic and the New World (A.
    [Show full text]
  • Comparison of the Plasmodium Species Which Cause Human Malaria
    Comparison of the Plasmodium Species Which Cause Human Malaria Plasmodium Stages found Appearance of Erythrocyte species in blood (RBC) Appearance of Parasite normal; multiple infection of RBC more delicate cytoplasm; 1-2 small chromatin Ring common than in other species dots; occasional appliqué (accollé) forms normal; rarely, Maurer’s clefts seldom seen in peripheral blood; compact Trophozoite (under certain staining conditions) cytoplasm; dark pigment seldom seen in peripheral blood; mature Schizont normal; rarely, Maurer’s clefts = 8-24 small merozoites; dark pigment, (under certain staining conditions) clumped in one mass P.falciparum crescent or sausage shape; chromatin in a Gametocyte distorted by parasite single mass (macrogametocyte) or diffuse (microgametocyte); dark pigment mass normal to 1-1/4 X,round; occasionally fine Ring Schüffner’s dots; multiple infection of RBC large cytoplasm with occasional not uncommon pseudopods; large chromatin dot enlarged 1-1/2–2 X;may be distorted; fine large ameboid cytoplasm; large chromatin; Trophozoite Schüffner’s dots fine, yellowish-brown pigment enlarged 1-1/2–2 X;may be distorted; fine large, may almost fill RBC; mature = 12-24 Schizont Schüffner’s dots merozoites; yellowish-brown, coalesced P.vivax pigment round to oval; compact; may almost fill enlarged 1-1/2–2 X;may be distorted; fine RBC; chromatin compact, eccentric Gametocyte Schüffner’s dots (macrogametocyte) or diffuse (micro- gametocyte); scattered brown pigment normal to 1-1/4 X,round to oval; occasionally Ring Schüffner’s dots;
    [Show full text]
  • Cerebral and Plasmodium Ovale Malaria in Rhode Island
    CASE REPORT Cerebral and Plasmodium ovale Malaria in Rhode Island JOSHUA KAINE, MD; JOSEPH MORAN-GUIATI, MD; JAMES TANCH, MD; BRIAN CLYNE, MD 64 67 EN ABSTRACT mortality. While the CDC currently reports a stable inci- We report two cases of malaria diagnosed in Rhode Is- dence of malaria in the US, climate change is predicted to land. First, a 21-year-old female who presented with 5 affect disease dynamics, and it remains unclear how the US days of fevers, chills, headache, and myalgias after return- incidence will be affected by climate change in the future.2,3 ing from a trip to Liberia, found to have uncomplicated Given the potentially fatal consequences of a missed malaria due to P. ovale which was treated successfully diagnosis of malaria and the relative inexperience of US with atovaquone/proguanil and primaquine. Second, a clinicians with the disease, we review two cases of malaria chronically ill 55-year-old male presented with 3 days of recently diagnosed in Rhode Island that are representative of headache followed by altered mental status, fever, and the spectrum of the disease one could expect to encounter in new-onset seizures after a recent visit to Sierra Leone, the US. The first is a classic, uncomplicated presentation of found to have P. falciparum malaria requiring ICU ad- malaria in a 21-year-old female and the second is an example mission and IV artesunate treatment. The diagnosis and of severe malaria in a chronically ill 55-year-old male. management of malaria in the United States (US), as well as its rare association with subdural hemorrhage are subsequently reviewed.
    [Show full text]
  • Malaria History
    This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. Your use of this material constitutes acceptance of that license and the conditions of use of materials on this site. Copyright 2006, The Johns Hopkins University and David Sullivan. All rights reserved. Use of these materials permitted only in accordance with license rights granted. Materials provided “AS IS”; no representations or warranties provided. User assumes all responsibility for use, and all liability related thereto, and must independently review all materials for accuracy and efficacy. May contain materials owned by others. User is responsible for obtaining permissions for use from third parties as needed. Malariology Overview History, Lifecycle, Epidemiology, Pathology, and Control David Sullivan, MD Malaria History • 2700 BCE: The Nei Ching (Chinese Canon of Medicine) discussed malaria symptoms and the relationship between fevers and enlarged spleens. • 1550 BCE: The Ebers Papyrus mentions fevers, rigors, splenomegaly, and oil from Balantines tree as mosquito repellent. • 6th century BCE: Cuneiform tablets mention deadly malaria-like fevers affecting Mesopotamia. • Hippocrates from studies in Egypt was first to make connection between nearness of stagnant bodies of water and occurrence of fevers in local population. • Romans also associated marshes with fever and pioneered efforts to drain swamps. • Italian: “aria cattiva” = bad air; “mal aria” = bad air. • French: “paludisme” = rooted in swamp. Cure Before Etiology: Mid 17th Century - Three Theories • PC Garnham relates that following: An earthquake caused destruction in Loxa in which many cinchona trees collapsed and fell into small lake or pond and water became very bitter as to be almost undrinkable. Yet an Indian so thirsty with a violent fever quenched his thirst with this cinchona bark contaminated water and was better in a day or two.
    [Show full text]
  • Package 'Malariaatlas'
    Package ‘malariaAtlas’ June 1, 2020 Title An R Interface to Open-Access Malaria Data, Hosted by the 'Malaria Atlas Project' Version 1.0.1 Description A suite of tools to allow you to download all publicly available parasite rate survey points, mosquito occurrence points and raster surfaces from the 'Malaria Atlas Project' <https://malariaatlas.org/> servers as well as utility functions for plot- ting the downloaded data. License MIT + file LICENSE Encoding UTF-8 LazyData true Imports curl, rgdal, raster, sp, xml2, grid, gridExtra, httr, dplyr, stringi, tidyr, methods, stats, utils, rlang Depends ggplot2 RoxygenNote 7.0.2 Suggests testthat, knitr, rmarkdown, palettetown, magrittr, tibble, rdhs URL https://github.com/malaria-atlas-project/malariaAtlas BugReports https://github.com/malaria-atlas-project/malariaAtlas/issues VignetteBuilder knitr NeedsCompilation no Author Daniel Pfeffer [aut] (<https://orcid.org/0000-0002-2204-3488>), Tim Lucas [aut, cre] (<https://orcid.org/0000-0003-4694-8107>), Daniel May [aut] (<https://orcid.org/0000-0003-0005-2452>), Suzanne Keddie [aut] (<https://orcid.org/0000-0003-1254-7794>), Jen Rozier [aut] (<https://orcid.org/0000-0002-2610-7557>), Oliver Watson [aut] (<https://orcid.org/0000-0003-2374-0741>), Harry Gibson [aut] (<https://orcid.org/0000-0001-6779-3250>), Nick Golding [ctb], David Smith [ctb] Maintainer Tim Lucas <[email protected]> 1 2 as.MAPraster Repository CRAN Date/Publication 2020-06-01 20:30:11 UTC R topics documented: as.MAPraster . .2 as.MAPshp . .3 as.pr.points . .4 as.vectorpoints . .5 autoplot.MAPraster . .6 autoplot.MAPshp . .7 autoplot.pr.points . .8 autoplot.vector.points . 10 autoplot_MAPraster . 11 convertPrevalence . 13 extractRaster .
    [Show full text]
  • Extra-Intestinal Coccidians Plasmodium Species Distribution Of
    Extra-intestinal coccidians Apicomplexa Coccidia Gregarinea Piroplasmida Eimeriida Haemosporida -Eimeriidae -Theileriidae -Haemosporiidae -Cryptosporidiidae - Babesiidae (Plasmodium) -Sarcocystidae (Sacrocystis) Aconoid (Toxoplasmsa) Plasmodium species Causitive agent of Malaria ~155 species named Infect birds, reptiles, rodents, primates, humans Species is specific for host and •P. falciparum vector •P. vivax 4 species cause human disease •P. malariae No zoonoses or animal reservoirs •P. ovale Transmission by Anopheles mosquito Distribution of Malarial Parasites P. vivax most widespread, found in most endemic areas including some temperate zones P. falciparum primarily tropics and subtropics P. malariae similar range as P. falciparum, but less common and patchy distribution P. ovale occurs primarily in tropical west Africa 1 Distribution of Malaria US Army, 1943 300 - 500 million cases per year 1.5 to 2.0 million deaths per year #1 cause of infant mortality in Africa! 40% of world’s population is at risk Malaria Atlas Map Project http://www.map.ox.ac.uk/index.htm 2 Malaria in the United States Malaria was quite prevalent in the rural South It was eradicated after world war II in an aggressive campaign using, treatment, vector control and exposure control Time magazine - 1947 (along with overall improvement of living Was a widely available, conditions) cheap insecticide This was the CDCs initial DDT resistance misssion Half-life in mammals - 8 years! US banned use of DDT in 1973 History of Malaria Considered to be the most
    [Show full text]
  • Sexual Development in Plasmodium Parasites: Knowing When It’S Time to Commit
    REVIEWS VECTOR-BORNE DISEASES Sexual development in Plasmodium parasites: knowing when it’s time to commit Gabrielle A. Josling1 and Manuel Llinás1–4 Abstract | Malaria is a devastating infectious disease that is caused by blood-borne apicomplexan parasites of the genus Plasmodium. These pathogens have a complex lifecycle, which includes development in the anopheline mosquito vector and in the liver and red blood cells of mammalian hosts, a process which takes days to weeks, depending on the Plasmodium species. Productive transmission between the mammalian host and the mosquito requires transitioning between asexual and sexual forms of the parasite. Blood- stage parasites replicate cyclically and are mostly asexual, although a small fraction of these convert into male and female sexual forms (gametocytes) in each reproductive cycle. Despite many years of investigation, the molecular processes that elicit sexual differentiation have remained largely unknown. In this Review, we highlight several important recent discoveries that have identified epigenetic factors and specific transcriptional regulators of gametocyte commitment and development, providing crucial insights into this obligate cellular differentiation process. Trophozoite Malaria affects almost 200 million people worldwide and viewed under the microscope, it resembles a flat disc. 1 A highly metabolically active and causes 584,000 deaths annually ; thus, developing a After the ring stage, the parasite rounds up as it enters the asexual form of the malaria better understanding of the mechanisms that drive the trophozoite stage, in which it is far more metabolically parasite that forms during development of the transmissible form of the malaria active and expresses surface antigens for cytoadhesion. the intra‑erythrocytic developmental cycle following parasite is a matter of urgency.
    [Show full text]
  • Screening and Identification of Potential Novel Biomarker for Diagnosis of Complicated Plasmodium Vivax Malaria
    Kaur et al. J Transl Med (2018) 16:272 https://doi.org/10.1186/s12967-018-1646-9 Journal of Translational Medicine RESEARCH Open Access Screening and identifcation of potential novel biomarker for diagnosis of complicated Plasmodium vivax malaria Hargobinder Kaur1, Rakesh Sehgal1*, Archit Kumar2, Alka Sehgal3, Devendra Bansal4 and Ali A. Sultan4 Abstract Background: In the recent years Plasmodium vivax has been reported to cause severe infections associated with mortality. Clinical evaluation has limited accuracy for the early identifcation of the patients progressing towards the fatal condition. Researchers have tried to identify the serum and the plasma-based indicators of the severe malaria. Discovery of MicroRNA (miRNA) has opened up an era of identifcation of early biomarkers for various infectious and non-infectious diseases. MicroRNAs (miRNA) are the small non-coding RNA molecules of length 19–24 nts and are responsible for the regulation of the majority of human gene expressions at post transcriptional level. Methods: We identifed the diferentially expressed miRNAs by microarray and validated the selected miRNAs by qRT-PCR. We assessed the diagnostic potential of these up-regulated miRNAs for complicated P. vivax malaria. Futher, the bioinformtic analysis was performed to construct protein–protein and mRNA–miRNA networks to identify highly regulated miRNA. Results: In the present study, utility of miRNA as potential biomarker of complicated P. vivax malaria was explored. A total of 276 miRNAs were found to be diferentially expressed by miRNA microarray and out of which 5 miRNAs (hsa-miR-7977, hsa-miR-28-3p, hsa-miR-378-5p, hsa-miR-194-5p and hsa-miR-3667-5p) were found to be signifcantly up-regulated in complicated P.
    [Show full text]
  • Evolutionary History of Human Plasmodium Vivax Revealed by Genome-Wide Analyses of Related Ape Parasites
    Evolutionary history of human Plasmodium vivax revealed by genome-wide analyses of related ape parasites Dorothy E. Loya,b,1, Lindsey J. Plenderleithc,d,1, Sesh A. Sundararamana,b, Weimin Liua, Jakub Gruszczyke, Yi-Jun Chend,f, Stephanie Trimbolia, Gerald H. Learna, Oscar A. MacLeanc,d, Alex L. K. Morganc,d, Yingying Lia, Alexa N. Avittoa, Jasmin Gilesa, Sébastien Calvignac-Spencerg, Andreas Sachseg, Fabian H. Leendertzg, Sheri Speedeh, Ahidjo Ayoubai, Martine Peetersi, Julian C. Raynerj, Wai-Hong Thame,f, Paul M. Sharpc,d,2, and Beatrice H. Hahna,b,2,3 aDepartment of Medicine, University of Pennsylvania, Philadelphia, PA 19104; bDepartment of Microbiology, University of Pennsylvania, Philadelphia, PA 19104; cInstitute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; dCentre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; eWalter and Eliza Hall Institute of Medical Research, Parkville VIC 3052, Australia; fDepartment of Medical Biology, The University of Melbourne, Parkville VIC 3010, Australia; gRobert Koch Institute, 13353 Berlin, Germany; hSanaga-Yong Chimpanzee Rescue Center, International Development Association-Africa, Portland, OR 97208; iRecherche Translationnelle Appliquée au VIH et aux Maladies Infectieuses, Institut de Recherche pour le Développement, University of Montpellier, INSERM, 34090 Montpellier, France; and jMalaria Programme, Wellcome Trust Sanger Institute, Genome Campus, Hinxton Cambridgeshire CB10 1SA, United Kingdom Contributed by Beatrice H. Hahn, July 13, 2018 (sent for review June 12, 2018; reviewed by David Serre and L. David Sibley) Wild-living African apes are endemically infected with parasites most recently in bonobos (Pan paniscus)(7–11). Phylogenetic that are closely related to human Plasmodium vivax,aleadingcause analyses of available sequences revealed that ape and human of malaria outside Africa.
    [Show full text]
  • Plasmodium Falciparum Full Life Cycle and Plasmodium Ovale Liver Stages in Humanized Mice
    ARTICLE Received 12 Nov 2014 | Accepted 29 May 2015 | Published 24 Jul 2015 DOI: 10.1038/ncomms8690 OPEN Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice Vale´rie Soulard1,2,3, Henriette Bosson-Vanga1,2,3,4,*, Audrey Lorthiois1,2,3,*,w, Cle´mentine Roucher1,2,3, Jean- Franc¸ois Franetich1,2,3, Gigliola Zanghi1,2,3, Mallaury Bordessoulles1,2,3, Maurel Tefit1,2,3, Marc Thellier5, Serban Morosan6, Gilles Le Naour7,Fre´de´rique Capron7, Hiroshi Suemizu8, Georges Snounou1,2,3, Alicia Moreno-Sabater1,2,3,* & Dominique Mazier1,2,3,5,* Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo. Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum, the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale-infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans. 1 Sorbonne Universite´s, UPMC Univ Paris 06, CR7, Centre d’Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Bd de l’hoˆpital, F-75013 Paris, France.
    [Show full text]
  • Phylogeny of the Malarial Genus Plasmodium, Derived from Rrna Gene Sequences (Plasmodium Falciparum/Host Switch/Small Subunit Rrna/Human Malaria)
    Proc. Natl. Acad. Sci. USA Vol. 91, pp. 11373-11377, November 1994 Evolution Phylogeny of the malarial genus Plasmodium, derived from rRNA gene sequences (Plasmodium falciparum/host switch/small subunit rRNA/human malaria) ANANIAS A. ESCALANTE AND FRANCISCO J. AYALA* Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92717 Contributed by Francisco J. Ayala, August 5, 1994 ABSTRACT Malaria is among mankind's worst scourges, is only remotely related to other Plasmodium species, in- affecting many millions of people, particularly in the tropics. cluding those parasitic to birds and other human parasites, Human malaria is caused by several species of Plasmodium, a such as P. vivax and P. malariae. parasitic protozoan. We analyze the small subunit rRNA gene sequences of 11 Plasmodium species, including three parasitic to humans, to infer their evolutionary relationships. Plasmo- MATERIALS AND METHODS dium falciparum, the most virulent of the human species, is We have investigated the 18S SSU rRNA sequences ofthe 11 closely related to Plasmodium reiehenowi, which is parasitic to Plasmodium species listed in Table 1. This table also gives chimpanzee. The estimated time of divergence of these two the known host and geographical distribution. The sequences Plasmodium species is consistent with the time of divergence are for type A genes, which are expressed during the asexual (6-10 million years ago) between the human and chimpanzee stage of the parasite in the vertebrate host, whereas the SSU lineages. The falkiparun-reichenowi lade is only remotely rRNA type B genes are expressed during the sexual stage in related to two other human parasites, Plasmodium malariae the vector (12).
    [Show full text]
  • Understanding the Global Endemicity of Falciparum and Vivax Malaria Ursula Dalrymple†, Bonnie Mappin† and Peter W
    Dalrymple et al. BMC Medicine DOI 10.1186/s12916-015-0372-x MINIREVIEW Open Access Malaria mapping: understanding the global endemicity of falciparum and vivax malaria Ursula Dalrymple†, Bonnie Mappin† and Peter W. Gething* Abstract The mapping of malaria risk has a history stretching back over 100 years. The last decade, however, has seen dramatic progress in the scope, rigour and sophistication of malaria mapping such that its global distribution is now probably better understood than any other infectious disease. In this minireview we consider the main factors that have facilitated the recent proliferation of malaria risk mapping efforts and describe the most prominent global-scale endemicity mapping endeavours of recent years. We describe the diversification of malaria mapping to span a wide range of related metrics of biological and public health importance and consider prospects for the future of the science including its key role in supporting elimination efforts. Keywords: Malaria, Mapping, Modelling, Falciparum, Vivax, Model-based geostatistics Introduction reconstruction of global malaria risk in the largely pre- Like most vector-borne diseases, malaria endemicity is industrial era and prior to widespread malaria control partly determined by the local environment that houses efforts [5] (Fig. 1). its human and anopheline hosts and mediates the inter- It is now nearly half a century since the Lysenko map actions between them. This environmental dependency was published and, during most of that period, few ef- leads to complex patterns of geographical variation in forts were made to improve on it. However, initiatives malaria transmission at almost every scale. Risk is rare- such as the continent-wide Mapping Malaria Risk in lyuniform whether considered between households in a Africa/Atlas du Risque de la Malaria en Afrique village, villages in a district or districts in a country [1].
    [Show full text]