Biological Sciences
Plasmodium spp
Plasmodium spp refers to a group of parasitic protozoa that are responsible for causing malaria in humans. There are several species within the Plasmodium genus, with P. falciparum and P. vivax being the most common. These parasites are transmitted to humans through the bites of infected female Anopheles mosquitoes and can cause severe illness if not treated promptly.
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12 Key excerpts on "Plasmodium spp"
- Dongyou Liu(Author)
- 2012(Publication Date)
- CRC Press(Publisher)
203 18 18.1 INTRODUCTION The. genus. Plasmodium . covers. a. diverse. group. of. proto-zoan. parasites. whose. life. cycle. involves. a. vertebrate. host. (e.g., . human,. monkey,. rodent,. bird,. and. reptile). and. a. mosquito. vector . . As. the. causal. agents. for. malaria,. a. dis-ease.that.has.been.recognized.since.time.immemorial.and. that.was.thought.to.result.from.exposure.to.bad.air.or.gas. from.swamps.(mal.air.ia.or.miasma),. Plasmodium .was.only. identified. in. 1880,. and. the. role. of. mosquito. in. its. trans-mission. was. elucidated. in. 1897 . . Of. > 200. species. within. the.genus,.five.(i .e., . Plasmodium falciparum ,. Plasmodium vivax ,. Plasmodium ovale ,. Plasmodium malariae ,. and. Plasmodium knowlesi ).are.capable.of.inducing.clinical.dis-ease.of.varying.severity.in.humans,.affecting.more.than.300. million.people.and.resulting.in.approximately.1 .5 .million. deaths.each.year . 18.1.1 C LASSIFICATION AND L IFE C YCLE 18.1.1.1 Classification The.genus. Plasmodium .is.classified.in.the.family.Plasmodiide,. order. Hemosporidia,. phylum. Apicomplexa . . In. addition. to. Plasmodium ,. the. family. Plasmodiide . includes. the. genera. of. Bioccala ,. Billbraya ,. Dionisia ,. Hepatocystis ,. Mesnilium ,. Nycteria ,. Polychromophilus ,. Rayella ,. and. Saurocytozoon. . The. genus. Plasmodium . can. be. further. distinguished. into. the. subgenera. of. Asiamoeba ,. Bennettinia . (type. species. Plasmodium juxtanucleare ),. Carinamoeba . (type. species. Plasmodium minasense ),. Fallisia ,. Garnia ,. Giovannolaia . (type. species. Plasmodium circumflexum ),. Hemamoeba . (type. species. Plasmodium relictum ),. Huffia . (type. species. Plasmodium elongatum ),. Lacertaemoba ,.
eBook - ePub- Patsy Jenson(Author)
- 2019(Publication Date)
- CRC Press(Publisher)
Plasmodium that have played a role in the studies of in vitro cultivation or that have, to date, been successfully cultivated. Malaria is not a disease of significant importance in animal husbandry except where poultry may be exposed to endemic infections in wild birds. Malaria in man, however, is of great medical importance and thus our discussion will cover principally the human species.Malaria, until recent times, has been the greatest killer of the human race, claiming half the total mortality of mankind.1 The tertiary malignant form, falciparum malaria, continues to rank chief among the infectious diseases with an estimated world incidence of over 300 million cases per annum. Africa alone accounts for nearly half of these cases with an annual mortality of 1 million, principally among children under 14 years of age.2 Of all the parasitic diseases, malaria is not only the greatest killer but is also the most widely spread. Approximately 2,015 million people live in areas where malaria has either been eradicated or where control measures are being attempted. Some 343 million people live in holoendemic areas where no specific programs of protection are being developed. The majority of these people live in Africa. Alarming as these figures are, the most disturbing aspect is. the major resurgence of malaria occurring in areas of the world where control of the disease was nearly successful, namely in Sri Lanka, India, Pakistan, Central and South America. This resurgence of malaria, and the failure to consolidate the gains made against malaria in control programs is due, in part, to the emergence of strains of anophelene mosquito vectors that are increasingly resistant to insecticides, chiefly the chlorinated hydrocarbons, but also the newly developed organophosphates. Another disturbing development is the spread of strains of Plasmodium falciparum that are resistant to antimalarial drugs, principally the 4-aminoqui-nolines — chloroquine and amodiaquine.3 In view of this disheartening epidemiological situation, new measures for the control of malaria are obviously needed. Chief among the new measures is the renewed effort for the development of an antimalarial vaccine. For decades, the hope for a malaria vaccine was frustrated by the failure to grow malaria parasites in culture. This obstacle was finally overcome by the work of Trager and Jensen4 who succeeded in growing a Southeast Asian strain of P. falciparum
eBook - PDFParasitic Protozoa
Babesia and Plasmodia
- Julius P. Kreier(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
C H A P T E R 4 Plasmodi a off Human s Francisc o J. Lopez-Antunan o an d Gabrie l A. Schmuni s I Introductio n Malaria in humans is an infection caused by parasites of the genus Plasmodium, class Sporozoa, that are transmitted in nature by the bite of an infected female mosquito of the genus Anopheles. The disease caused by this parasite usually is characterized by intermittent febrile paroxysms, anemia, and spleen enlargement (Russell, 1968; Bruce-Chwatt, 1985). When parasites multiply in the bloodstream and invade more than 1% of the red blood cells, a cascade of effects may produce a severe and complicated disease that can terminate in coma and death of the victim if adequate diagnosis and proper treatment are not provided in time (Hall, 1976). The most common synonyms for malaria in the English language are Roman, marsh, jungle, intermittent, paroxysmal, and periodic fever; ague (Bruce-Chwatt, 1976); and chills and fever. In other languages and in cultures in which malaria is endemic, the variety of terms for malaria is enriched by the people's interpretation of the disease or by the imagination of writers and poets. When, how, and why plasmodia invaded humans is a rather philosophical question that will not be addressed in this chapter. However, we will share the perspective of the Greek physicians of the fifth century B .C. , who were very familiar with malarial fevers and the association of those diseases with marshes. In his book Airs, Waters, and Places, Hippocrates (English translation by Jones, 1923) states his belief in the balance between humans and their environment; this statement constitutes the first known systematic endeavor to present a causal relationship between environmental risk factors and disease.
eBook - PDF- Julius P. Kreier(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
On the other hand, a considerable portion of what we know today about various other facets of avian malaria has come from work on the mammalian species of Plasmodium. However, the avian plasmodia are important protozoan parasites because they are utilized extensively for ecolog-ical modeling of host-parasite systems (e.g., Hamilton and Zuk, 1982; Read, 1988; Atkinson and van Riper, 1991). Ecologists, ethologists, and wildlife disease work-ers now are recognizing the importance of data on distribution and prevalence of PARASITIC PROTOZOA, VOLUME 7 Copyright © 1994 by Academic Press, Inc. All rights of reproduction in any form reserved. 73 74 Charles van Riper III et al. avian plasmodia for study of ecological, behavioral, and evolutionary problems arising in host-parasite systems. In this chapter, we first provide a brief historical review of the research that has been done on avian malaria. This review is followed by a discussion of the avian plasmodia, their life cycles, and their taxonomic affinities. W e then provide information on the vectors that have been implicated in the transmission of avian plasmodia. The next part of this chapter provides information on advances in knowledge of the development, ultrastructure, metabolism, biochemistry, and cultivation of the avian plasmodia. W e then deal with clinical aspects of the disease, the pathogenicity of avian plasmodia, and factors affecting host resistance and immunity. In concluding the chapter, we provide examples of epizootiological studies of malaria in birds and discuss how data from such studies may be used to model host-parasite systems. II· Historical Review Avian malaria first was reported to occur in Russia (Danilewsky, 1885). Dani-lewsky (1885) documented the morphology of the parasites and their effects on avian hosts; in addition, he demonstrated the process of exflagellation in fresh blood.
eBook - ePub- Michel Tibayrenc(Author)
- 2017(Publication Date)
- Elsevier(Publisher)
21Genomic Insights Into the Past, Current, and Future Evolution of Human Parasites of the Genus Plasmodium
C.J. Sutherland1 , and S.D. Polley21 London School of Hygiene & Tropical Medicine, London, United Kingdom2 Hospital for Tropical Diseases, London, United KingdomAbstract
Malaria parasites comprise a number of successful genera of unicellular eukaryotes. Plasmodium is the best known of these genera; its members infect a wide variety of vertebrate hosts, and disperse among these hosts with the assistance of hematophagic insect vectors. The radiation of this group of organisms has occurred in step with the vertebrate expansion of the last 120 million years, and thus transitions to new hosts, followed by adaptation to those hosts, have been a major driving force in the evolution of Plasmodium . The effects of each such transition can be discerned in the genomes of the forms seen today. These historical forces remain in place as sources of evolutionary selection but, for the Homo sapiens –infecting species of Plasmodium , current human interventions such as use of antimalarial drugs, and the implementation of vaccines in the coming decades are likely to provide novel sources of (un)natural selection. This chapter provides a brief overview of the signals of historical evolution in the Plasmodium genomes thus far examined, with particular emphasis on host transitions, speciation events, and selective effects on the parasite genome of antiparasite drugs and of any vaccines that may be used as malaria control tools in the future. Finally, we consider the likely depth and breadth of evolutionary pressure to be exerted by malaria eradication programs now being planned across endemic zones.Keywords
Drug resistance; Host transition; Immune selection; Malaria; Plasmodium ; Speciation1. Introduction
1.1. Overview of Plasmodium
eBook - PDF- (Author)
- 0(Publication Date)
- The National Academies Press(Publisher)
6 Parasite Biology WHERE WANT TO BE IN THE YEAR 2010 For centuries, malaria parasites have successfully evaded the biological defenses of their human hosts. Researchers are perplexed by the complexity of these organisms, and many questions remain un-answered. By the year 2010, advances in the field of parasite biology will have exposed many of the complex biochemical mechanisms that allow this evasion to occur. A detailed understanding of how malaria parasites recognize and invade human liver and red blood cells, for example, how their multistage life cycle is regulated and how they rapidly become drugresistant will have provided a major boost to efforts to develop malaria vaccines and will have resulted in innovative approaches to more durable antimalarial drugs. WHERE WE ARE TODAY The Parasite The human malaria parasite—actually four species of the genus Plasmodium —undergoes over a dozen distinguishable of development as it moves from the mosquito vector to the human host and back again. One way to conceptualize this complex life cycle is to consider it in three distinct parts: the liver phase, the blood phase, and the mosquito phase. PARASITE BIOLOGY 90 Malaria: Obstacles and Opportunities Copyright National Academy of Sciences. All rights reserved. Depending on the developmental stage and species, malaria parasites can be spherical, ring shaped, elongated, or crescent shaped, and can range in size from 1 to 20 microns in diameter (1 micron equals 1 millionth of a meter or approximately 125,000 of an inch). By comparison, a normal red blood cell has a diameter of about 7 microns. Although the four species of human malaria parasites are closely related, there are major differences among them. Plasmodium falciparum , the most pathogenic of the four species, has been found to be more closely related to avian and rodent species of Plasmodium than to the other primate and human species (McCutchan et al., 1984).
eBook - ePub- Harold Benjamin Fantham(Author)
- 2018(Publication Date)
- Perlego(Publisher)
Plasmodium tenue. It is very amœboid, with scanty cytoplasm and much chromatin, sometimes rod-like or irregular. The parasite was described from a blood-smear of an Indian child. The creation of a new species for this parasite has been criticized by Balfour and Wenyon, and by Craig.Plasmodium relictum, Sergent, 1907.Syn.: Plasmodium præcox, Grassi and Feletti, 1890; Plasmodium danilewskyi, Gr. et Fel., 1890; Hæmamœba relicta, Gr. et Fel., 1891; Proteosoma grassii, Labbé, 1894.Hæmamœboid, pigment-producing, malarial parasites are often found in birds. Like the human malarial parasites they have been variously named. Labbé created the genus Proteosoma for them, and this name is still often used as a distinctive one unofficially. The correct name is stated to be either Plasmodium relictum or P. præcox, or possibly even P. danilewskyi, assuming that there is only one species. The nomenclature of the malarial parasites is most confused. The avian malarial parasites are transmitted by Culicine mosquitoes.The organism was discovered by Grassi in the blood of birds in Italy, and causes a fatal disease in partridges in Hungary. Sparrows are affected in India, and it was this Plasmodium in which Ross first traced the development of a malarial parasite in a mosquito. The parasite may be transmitted from bird to bird by blood-inoculation, canaries being very susceptible.The principal stages of the avian plasmodium closely resemble those of the malarial parasites of man. In its earliest stage P. relictum is unpigmented, but soon the trophozoite grows and becomes pigmented, meanwhile displacing the nucleus of the avian red-blood corpuscle, a characteristic feature, distinguishing it from Halteridium. Schizonts are formed, each of which gives rise to about nine merozoites in the circulating blood. Sexual forms or gametocytes also occur in the blood. These develop in Culex fatigans, C. pipiens and C. nemorosus
eBook - ePub- Peter Lydyard, Michael Cole, John Holton, Will Irving, Nino Porakishvili, Pradhib Venkatesan, Kate Ward(Authors)
- 2023(Publication Date)
- CRC Press(Publisher)
Plasmodium spp.A 26-year-old model went to see her doctor about 1 week after returning from a job in the Gambia. She complained of an abrupt onset of bouts of shivering and feeling cold, vomiting, rigors, and profuse sweating accompanied by a headache and nausea. On examination, she was noted to be pale with a temperature of 39.5°C and had tachycardia. She gave a history of having taken anti-malarial tablets before and during her stay in the Gambia but was admitted to hospital with a provisional diagnosis of malaria.1. WHAT IS THE CAUSATIVE AGENT, HOW DOES IT ENTER THE BODY AND HOW DOES IT SPREAD A) WITHIN THE BODY AND B) FROM PERSON TO PERSON?
CAUSATIVE AGENT
The organism causing malaria is Plasmodium, a eukaryotic protozoan that infects the erythrocytes of humans. It has the characteristics of eukaryotes, with a nucleus, mitochondria, endoplasmic reticulum, and so forth. There are approximately 156 named species of Plasmodium which infect various vertebrates. Five species of Plasmodium are able to infect humans: P. falciparum, P. ovale, P. vivax, P. malariae and P. knowlesi. P. falciparum is the most virulent species of malaria but P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa. All of these species have similar life cycles in which the organisms undergo both sexual and asexual reproduction in the vector and host and alternate between intracellular and extracellular forms. The female Anopheles mosquito is the vector for malaria. The risk of malaria transmission is therefore restricted to those areas where mosquitoes can breed and where the parasite can develop within the mosquito – see Epidemiology below.ENTRY AND SPREAD WITHIN THE BODY
The transmission stage of Plasmodium is the sporozoite, which is injected into the bloodstream of a human when the female Anopheles mosquito takes a blood meal (Figure 28.1 ). The detailed life cycle is shown in Figure 28.2
eBook - ePub- Richard Lucius, Brigitte Loos-Frank, Richard P. Lane, Robert Poulin, Craig Roberts, Richard K. Grencis, Ron Shankland, Renate FitzRoy, Ron Shankland, Renate FitzRoy(Authors)
- 2017(Publication Date)
- Wiley-VCH(Publisher)
P. falciparum is an important selection factor. Individuals who develop effective immune responses against certain Plasmodium antigens therefore have a better chance of survival and reproduction. The potential to respond to certain antigens is significantly influenced by genes of the MHC system and certain MHC alleles are associated with resistance to cerebral malaria and other susceptibility to disease. Other normally disadvantageous genetic factors that reduce the severity of malaria can be a selective advantage in geographical areas, where malaria is prevalent. Examples include genetically acquired hemoglobin abnormalities, including sickle cell anemia and hereditary deficiency of glucose-6-phosphate dehydrogenase. Several polymorphisms in cytokine genes have also been demonstrated to have a protective effect against malaria (see Section 1.4.4).2.6.3.6 Plasmodium species of Monkeys, Rodents, and Birds
Numerous species of Old and New World monkeys are naturally infected with various species of Plasmodium and the host parasite relationship can have certain similarities with that of humans. Consequently, these host and parasites have gained importance as animal models in research. Plasmodium cynomolgi was first discovered in Macaques monkeys (Macaca irus) in Java and its biology has parallels with that of P. vivax, including the ability to form hypnozoites. P. cynomolgi was exploited in the development of Primaquine, a drug that is effective against hypnozoites. Plasmodium knowlesi was isolated from macaques in India, and causes a disease similar to Malaria tropica. The parasite can be transmitted to rhesus monkeys, for example, in which it can cause deadly infections.Closely related to the human pathogenic Plasmodium parasites Plasmodium berghei is often used as an animal model for biomedical studies. P. berghei is a natural parasite of the gallery forest rat Grammomys surdaster, which occurs in the higher regions of Central Africa, but can be used experimentally in a variety of rodents. The susceptibility of different rodent species varies considerably and is somewhat age-dependent. While old rats are resistant to infection, it is fatal in mice and young rats, which develop cerebral malaria. P. berghei has therefore been used in many experimental studies and as a teaching tool. The deposition of hemozoin in macrophages of the liver and spleen as well the presence of blood schizonts can be easily demonstrated. Plasmodium yoelii, Plasmodium chabaudi, and Plasmodium vinckei are three other species that infect African gallery forest rats and are used as model organisms. Due to its importance, the genome of P. yoelii was sequenced at the same time as that of P. falciparum. Further genome analyses have uncovered further variable antigen gene families implicated in adhesion in a number of Plasmodium species. These include rif/stevor
eBook - ePub- Michel Tibayrenc(Author)
- 2010(Publication Date)
- Elsevier(Publisher)
Hall et al., 2005 ).22.3. Evolution of Plasmodium: The Twenty-First Century in Three Courses22.3.1. Entree: Habitat Destruction and Ecological TransitionsHost transitions in malaria parasites require contact between the novel vertebrate host species and insect vectors that have bitten infected individuals of the primary vertebrate host species. Thus human (and prehuman) migration, settlement, and the resulting encroachment of human activity into the habitats of different nonhuman primates have been the probable driving force behind the prehistorical transitions discussed in Section 22.2 . In the twenty-first century, human migrations still occur, and encroachment into the habitats of wild simian and ape populations continue. Coupled with a recent improvement in our ability to discern the presence of unusual Plasmodium species in humans with malaria, these continued close encounters between humans and the parasites of beasts will be more commonly recognized. Further, the destruction of habitat and the resulting decline in numbers of the great apes means that the parasite species dependent on them as hosts are under selective pressure to expand their host range. This may increase the likelihood of new transitions into human-centered parasitism.The recent description of additional wild isolates of P. reichenowi (Prugnolle et al., 2010 ), and additional falciparum-like members of Plasmodium in African great apes (Liu et al., 2010), raises the possibility that human infections with these parasites may be relatively common in some parts of Africa, but have failed to be recognized. This is not least because remnant populations of the nonhuman hominids exist in relatively remote locations, where people suffering from malaria who do come in contact with health services are likely to be treated (if at all) without any diagnosis, and certainly without a species-specific one (Sutherland et al., 2010
eBook - PDFHemoparasites of the Reptilia
Color Atlas and Text
- Jr., Sam R. Telford(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
The Plasmodiid Parasites 1 In the first decade of the 20th century the first reptilian malarial parasites were recognized, joining those reported from humans and birds within the previous 20 years. Wenyon (1909a), during his tenure as traveling protozoolo-gist for the Wellcome Research Laboratories, found Plas-modium agamae and P. mabuiae in agamid and scincid lizards of the Sudan. In the same year, and with priority to Wenyon’s discovery, two species, Plasmodium diploglossi and P. tropiduri , were described from Brazil in anguid and tropidurid lizards (Aragão and Neiva, 1909). The pace of species discovery and description rose slowly until the 1960s, with only 29 species and subspecies recognized by Garnham from reptiles in his classic Malarial Parasites and Other Haemosporidia , which appeared in 1966. At the end of that decade, the recognition of Plasmodium species and species of related genera began to rise in seemingly geometric progression, with 87 taxa known by 1989 (Tel-ford, 1994), then slowed in the 1990s, with 101 species and subspecies of Plasmodium sensu stricto described or under description by 2007, as well as 37 other related species of plasmodiids: Garnia (10), Fallisia (10), Haemocystidium (14), Saurocytozoon (2), and Progarnia (1). To a consid-erable extent, this proliferation resulted from long-term residence in endemic areas by parasitologists interested in these organisms, in contrast to brief visits with the limited collections possible by traveling scientists or physicians, often with other primary interests. Most articles dealing with reptilian plasmodiids have been taxonomic until recently, when interest arose in using plasmodiids as examples supporting ecological theory.
eBook - PDFAnopheles mosquitoes
New insights into malaria vectors
- Sylvie Manguin(Author)
- 2013(Publication Date)
- IntechOpen(Publisher)
Section 4 Pathogen Transmission and Influencing Factors Chapter 15 Simian Malaria Parasites: Special Emphasis on Plasmodium knowlesi and Their Anopheles Vectors in Southeast Asia Indra Vythilingam and Jeffery Hii Additional information is available at the end of the chapter http://dx.doi.org/10.5772/54491 1. Introduction Simian malaria parasites were first reported in Malayan monkeys by Daniels in 1908 [1]. It had been assumed for a long time that transmission of simian malaria to humans would not be possible. However, an accidental infection of scientists in Atlanta, USA by mosquito bites in the laboratory proved that a simian malaria species– Plasmodium cynomolgi can be transmitted to humans [2, 3]. In 1965 the first natural infection in human was reported in an American surveyor who was infected in the jungles of Pahang, Malaysia [4]. Fortunately he returned to USA and was detected first as Plasmodium falciparum and later revised to Plasmodium malariae due to the band form of the parasite. Further examination proved that it was actually Plasmo‐ dium knowlesi [4]. Plasmodium knowlesi was first found in Macaca fascicularis monkeys that were brought to India from Singapore. Drs Knowles and Das Gupta knew that they were dealing with a new malaria parasite but did not provide a binomial nomenclature. It was Sinton and Muligan who formally named the new species as P. knowlesi [5] after Dr. Knowles. Studies that were carried out before the first human case was reported unveiled many new simian malaria parasites but no human cases. After the first human case was reported in 1965, blood samples were collected from about 1000 people from surrounding villages in West Malaysia where the case of P. knowlesi was found but none were positive for simian malaria [6]. However, a presumptive case was reported from Johore, a southern state in peninsular Malaysia [7].
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