scholarly journals Plasmodium—a brief introduction to the parasites causing human malaria and their basic biology

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Shigeharu Sato
Keyword(s):  
Socioeconomic Development ◽  
Parasite Species ◽  
Insect Vector ◽  
Protozoan Parasites ◽  
Zoonotic Malaria ◽  
Causative Agents ◽  
Basic Biology ◽  
Vertebrate Hosts ◽  
The Individual ◽  
Anopheline Mosquitoes

AbstractMalaria is one of the most devastating infectious diseases of humans. It is problematic clinically and economically as it prevails in poorer countries and regions, strongly hindering socioeconomic development. The causative agents of malaria are unicellular protozoan parasites belonging to the genus Plasmodium. These parasites infect not only humans but also other vertebrates, from reptiles and birds to mammals. To date, over 200 species of Plasmodium have been formally described, and each species infects a certain range of hosts. Plasmodium species that naturally infect humans and cause malaria in large areas of the world are limited to five—P. falciparum, P. vivax, P. malariae, P. ovale and P. knowlesi. The first four are specific for humans, while P. knowlesi is naturally maintained in macaque monkeys and causes zoonotic malaria widely in South East Asia. Transmission of Plasmodium species between vertebrate hosts depends on an insect vector, which is usually the mosquito. The vector is not just a carrier but the definitive host, where sexual reproduction of Plasmodium species occurs, and the parasite’s development in the insect is essential for transmission to the next vertebrate host. The range of insect species that can support the critical development of Plasmodium depends on the individual parasite species, but all five Plasmodium species causing malaria in humans are transmitted exclusively by anopheline mosquitoes. Plasmodium species have remarkable genetic flexibility which lets them adapt to alterations in the environment, giving them the potential to quickly develop resistance to therapeutics such as antimalarials and to change host specificity. In this article, selected topics involving the Plasmodium species that cause malaria in humans are reviewed.

Genetic diversity of zoonotic malaria parasites from mosquito vector and vertebrate hosts

2019 ◽  
Vol 73 ◽  
pp. 26-32 ◽  
Author(s):  
Meng Li Wong ◽  
Md Atique Ahmed ◽  
Wan Yusoff Wan Sulaiman ◽  
Benny O. Manin ◽  
Cherng Shii Leong ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Mosquito Vector ◽  
Malaria Parasites ◽  
Zoonotic Malaria ◽  
Vertebrate Hosts

scholarly journals Origin of a major infectious disease in vertebrates: The timing of Cryptosporidium evolution and its hosts

Parasitology ◽  
2016 ◽  
Vol 143 (13) ◽  
pp. 1683-1690 ◽  
Author(s):  
JUAN C. GARCIA-R ◽  
DAVID T. S. HAYMAN
Keyword(s):  
Infectious Disease ◽  
Adaptive Radiation ◽  
Strong Support ◽  
Molecular Clocks ◽  
Protozoan Parasites ◽  
Host Shifts ◽  
Parasite Lineage ◽  
Vertebrate Hosts ◽  
Major Infectious Disease ◽  
Age Estimates

SUMMARYProtozoan parasites of the genus Cryptosporidium infect all vertebrate groups and display some host specificity in their infections. It is therefore possible to assume that Cryptosporidium parasites evolved intimately aside with vertebrate lineages. Here we propose a scenario of Cryptosporidium–Vertebrata coevolution testing the hypothesis that the origin of Cryptosporidium parasites follows that of the origin of modern vertebrates. We use calibrated molecular clocks and cophylogeny analyses to provide and compare age estimates and patterns of association between these clades. Our study provides strong support for the evolution of parasitism of Cryptosporidium with the rise of the vertebrates about 600 million years ago (Mya). Interestingly, periods of increased diversification in Cryptosporidium coincides with diversification of crown mammalian and avian orders after the Cretaceous-Palaeogene (K-Pg) boundary, suggesting that adaptive radiation to new mammalian and avian hosts triggered the diversification of this parasite lineage. Despite evidence for ongoing host shifts we also found significant correlation between protozoan parasites and vertebrate hosts trees in the cophylogenetic analysis. These results help us to understand the underlying macroevolutionary mechanisms driving evolution in Cryptosporidium and may have important implications for the ecology, dynamics and epidemiology of cryptosporidiosis disease in humans and other animals.

Checklist of Protozoan parasites of fishes from Brazil

Zootaxa ◽  
2012 ◽  
Vol 3221 (1) ◽  
pp. 1 ◽  
Author(s):  
JORGE C. EIRAS ◽  
RICARDO M. TAKEMOTO ◽  
GILBERTO C. PAVANELLI ◽  
JOSÉ L. LUQUE
Keyword(s):  
Host Species ◽  
Parasite Species ◽  
Marine Fishes ◽  
Protozoan Parasites ◽  
Host Habitat

Provided is a list of the protozoan parasites of freshwater and marine fishes from Brazil. This report includes informationabout the site of infection, host habitat, localities and references of 100 parasite species (1 amoeba, 70 flagellates, 13 api-complexa and 16 ciliates) distributed among 112 different host species, mainly from freshwater. It is concluded that thediversity of protozoan parasites from Brazilian fish is understudied, and it is suggested that appropriate measures be taken in the research efforts to increase studies on the diversity of Protozoans parasites of fish from Brazil.

A note on the defence reactions of insects to Protozoa

Parasitology ◽  
1969 ◽  
Vol 59 (4) ◽  
pp. 753-756 ◽  
Author(s):  
George Salt
Keyword(s):  
Protozoan Parasites ◽  
Metazoan Parasites ◽  
Vertebrate Hosts ◽  
Defence Reactions

It is well known that the defence reactions of insects to metazoan parasites are principally cellular rather than humoral; and it has recently been shown that the habitual parasitoids of an insect have means of resisting or avoiding the defence reactions of their host (Salt, 1968). Those two findings suffest that it may be necessary to re-examine the situation with regard to protozoan parasites, including some genera for which insects act as vectors between vertebrate hosts. Two examples will serve to draw attention to the problems involved.

A review of the infectious agents, parasites, pathogens and commensals of European cockles (Cerastoderma eduleandC. glaucum)

2012 ◽  
Vol 93 (1) ◽  
pp. 227-247 ◽  
Author(s):  
Matt Longshaw ◽  
Shelagh K. Malham
Keyword(s):  
Systematic Review ◽  
Life Cycle ◽  
Parasite Species ◽  
Future Research ◽  
Infectious Agents ◽  
Cerastoderma Edule ◽  
Cerastoderma Glaucum ◽  
Burrowing Behaviour ◽  
The Individual ◽  
Population Effects

A systematic review of the parasites, pathogens and commensals of the edible cockle (Cerastoderma edule) and of the lagoon cockle (Cerastoderma glaucum) has been completed. A total of 59 different conditions have been reported throughout the range of both of these hosts; of these 50 have been reported in edible cockles, and 28 in lagoon cockles. Cockles are hosts to viruses, bacteria, fungi (including Microsporidia), Apicomplexa, Amoeba, Ciliophora, Perkinsozoa, Haplosporidia, Cercozoa, Turbellaria, Digenea, Cestoda, Nematoda, Crustacea and Nemertea. A number of these have been reported sporadically although they may be associated with mortalities. In particular, mortalities have been associated predominately with digeneans and some protistan infections. In many cases pathology is marked in affected animals and parasites have been shown to reduce fecundity, alter burrowing behaviour and limit growth. This review provides information on the individual and population effects of these conditions as well as providing suggestions for future research. In particular, there has been a lack of taxonomic rigour applied to many studies and as a result there are a number of erroneous host records. There is a need to re-describe a number of parasite species and to determine the life cycle of those considered to be important mortality drivers.

LB Broth-lyophilized Rabbit Anti-sheep Cell Haemolysin as a Simple Culture Medium for Cultivation of Leishmania Major Promastigotes

2019 ◽  
Author(s):  
Vahid Nasiri ◽  
Farnoosh Jameie ◽  
Habibollah Paykari
Keyword(s):  
Blood Cell ◽  
Culture Medium ◽  
Leishmania Major ◽  
Low Cost ◽  
Protozoan Parasites ◽  
Causative Agents ◽  
Genus Leishmania ◽  
Leishmania Parasites ◽  
Growth Ability

Background and Aims: The protozoan parasites of the genus Leishmania are the causative agents of various clinical diseases. Different methods of cultivation of Leishmania parasites are available. In the present study, the efficacy of the LB broth with rabbit lyophilized anti-sheep red blood cell haemolysin was evaluated in the cultivation of promastigotes of Leishmania major. Materials and Methods: Conventional LB broth medium was prepared and autoclaved for 15 min at 121°C and then lyophilized rabbit anti-sheep cell haemolysin was added at 1-10% final concentrations. The efficacy of the medium was evaluated by assessing the growth ability and replication patterns of the promastigotes of Leishmania major. Results: Medium with 1-10% lyophilized rabbit haemolysin supported the growth of the parasites and can be used for cultivation of Leishmania parasites with acceptable In vivo infectivity for research purpose. Conclusions: The ability of the parasites to survive and proliferate in the presence of lyophilized rabbit haemolysin indicates that this material is a good nutritional source. This study opens a new way to make low-cost medium that can be used in cultivation of Leishmania parasites

Cardiorespiratory Effects Following Acute Exposure to Pyridostigmine Bromide and/or N,N-Diethyl-m-toluamide (DEET) in Rats

2002 ◽  
Vol 21 (4) ◽  
pp. 287-300 ◽  
Author(s):  
Leslie A. Chaney ◽  
Robin W. Rockhold ◽  
Arthur S. Hume
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Tidal Volume ◽  
Blood Gases ◽  
Pyridostigmine Bromide ◽  
Whole Body ◽  
Receptor Sites ◽  
Arterial Ph ◽  
Causative Agents ◽  
The Individual

The acute lethal interaction that occurs in rodents when high doses of a peripherally restricted cholinesterase inhibitor, pyridostigmine bromide (PB), and the insect repellent N,N-diethyl-m-toluamide (DEET) are combined was first described during studies of chemical mixtures that were targeted as potential causative agents of Gulf War illnesses. This study was intended to provide insight into possible mechanisms of that lethal interaction. Following a single intraperitoneal injection of PB (2 mg/kg) and/or DEET (300 or 500 mg/kg), respiratory activity was measured in conscious freely moving rats using whole-body plethysmography. Cardiovascular function was also monitored simultaneously through an arterial catheter. PB (2 mg/kg) given alone stimulated respiration and increased blood pressure. Arterial pH levels were decreased, whereas pO2 and pCO2 remained at control levels. Administration of DEET (300 mg/kg) alone increased tidal volume and decreased blood pressure. Blood gases and pH levels were unaltered. A higher dose of DEET (500 mg/kg) also decreased respiratory and heart rate. Coadministration of PB (2 mg/kg) and DEET (300 mg/kg) increased tidal volume, decreased arterial pH, and elevated pCO2. Heart rate and blood pressure declined progressively after drug coadministration. Pretreatment with atropine methyl nitrate (AMN), a peripherally selective competitive antagonist at nicotinic and muscarinic receptor sites, reduced the individual effects of PB or DEET, and significantly increased survival after co-exposure to these agents. Although changes in respiratory function may have contributed to the lethal interaction, it was concluded that the primary cause of death was circulatory failure.

In vitrocytokines profile and ultrastructural changes of microglia and macrophages following interaction withLeishmania

Parasitology ◽  
2014 ◽  
Vol 141 (8) ◽  
pp. 1052-1063 ◽  
Author(s):  
PATRICIA KARLA SANTOS RAMOS ◽  
MAYSA DE VASCONCELOS BRITO ◽  
FERNANDO TOBIAS SILVEIRA ◽  
CLÁUDIO GUEDES SALGADO ◽  
WANDERLEY DE SOUZA ◽  
...  
Keyword(s):  
Immune Responses ◽  
Parasite Species ◽  
Morphological Changes ◽  
Expression Patterns ◽  
Ultrastructural Changes ◽  
American Cutaneous Leishmaniasis ◽  
Causative Agents ◽  
Infected Cells ◽  
Robust Response

SUMMARYIn the present study, we assessed morphological changes and cytokine production afterin vitrointeraction with causative agents of American cutaneous leishmaniasis and compared the microglia and macrophage immune responses. Cultures of microglia and macrophages infected with stationary-phase promastigotes ofLeishmania(Viannia)shawi, Leishmania(Viannia)braziliensisorLeishmania(Leishmania)amazonensiswere evaluated 24, 48 and 72 h after interaction. Macrophages only presented the classical phagocytic process while microglia also displayed large cytoplasmic projections similar to the ruffles described in macropinocytosis. In the macrophage cultures, the percentage of infected cells increased over time, in a fashion that was dependent on the parasite species. In contrast, in microglial cells as the culture time progressed, there was a significant reduction in the percentage of infected cells independent of parasite species. Measurements of cytokines in macrophage cultures 48 h after interactions revealed distinct expression patterns for different parasites, whereas in microglial cultures they were similar for allLeishmaniatested species. Taken together, our results suggest that microglia may have a higher phagocytic ability and cytotoxic potential than macrophages for all investigated species. The robust response of microglia against all parasite species may suggest microglia have an important role in the defence against cerebral leishmaniasis.

scholarly journals Physicochemical Aspects of thePlasmodium chabaudi-Infected Erythrocyte

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Eri H. Hayakawa ◽  
Seiki Kobayashi ◽  
Hiroyuki Matsuoka
Keyword(s):  
Parasite Species ◽  
Infected Erythrocyte ◽  
Microscopic Analysis ◽  
Erythrocyte Membranes ◽  
Molecular Profile ◽  
Evolutionary Time ◽  
Electron Microscopic ◽  
Intracellular Parasites ◽  
Causative Agents ◽  
Zeta Potential Analysis

Membrane electrochemical potential is a feature of the molecular profile of the cell membrane and the two-dimensional arrangement of its charge-bearing molecules.Plasmodiumspecies, the causative agents of malaria, are intracellular parasites that remodel host erythrocytes by expressing their own proteins on erythrocyte membranes. Although various aspects of the modifications made to the host erythrocyte membrane have been extensively studied in some humanPlasmodiumspecies (such asPlasmodium falciparum), details of the structural and molecular biological modifications made to host erythrocytes by nonhumanPlasmodiumparasites have not been studied. We employed zeta potential analysis of erythrocytes parasitized byP. chabaudi, a nonhumanPlasmodiumparasite. From these measurements, we found that the surface potential shift was more negative forP. chabaudi-infected erythrocytes than forP. falciparum-infected erythrocytes. However, electron microscopic analysis of the surface ofP. chabaudi-infected erythrocytes did not reveal any modifications as compared with nonparasitized erythrocytes. These results suggest that differences in the membrane modifications found herein represent unique attributes related to the pathogenesis profiles of the two different malaria parasite species in different host animals and that these features have been acquired through parasite adaptations acquired over long evolutionary time periods.

The evolution of bluetongue virus: genetic and phenotypic diversity of field strains

2013 ◽  
Vol 16 (3) ◽  
pp. 611-616 ◽  
Author(s):  
W. Niedbalski
Keyword(s):  
Genetic Drift ◽  
Bluetongue Virus ◽  
Phenotypic Diversity ◽  
Intragenic Recombination ◽  
Insect Vector ◽  
Phenotypic Properties ◽  
A Genome ◽  
Different Strains ◽  
The Individual ◽  
Genetic Shift

AbstractBluetongue virus (BTV), the aetiological agent of bluetongue (BT), is a small (about 70 nm in diameter) icosahedral virus with a genome composed of ten linear segments of double-stranded RNA (dsRNA), which is packaged within an icosahedral nucleocapsid composed of seven structural proteins. The BTV genome evolves rapidly via genetic drift, reassortment of genome segments (genetic shift) and intragenic recombination. This evolution, and random fixation of quasispecies variants during transmission of BTV between susceptible animals and vectors appear to be the main mechanism leading to the observed genetic diversity amongst BTV field strains. The individual BTV gene segments evolve independently of one another by genetic drift in a host-specific fashion, generating quasispecies populations in both ruminant and insect hosts. Reassortment of BTV genes is responsible for genetic shift among strains of BTV, and has been demonstrated after infection of either the ruminant host or insect vector with different strains or serotypes of BTV. Intragenetic recombination, whereby mosaic genes are generated from the “splicing” together of homologous genes from different ancestral viral strains, has been demonstrated for BTV. The genetic variation of BTV is likely responsible for differences in the virulence and other phenotypic properties of individual field strains of the virus.

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