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artesunate-tafenoquine combination therapy promotes clearance and abrogates transmission of the avian malaria parasite plasmodium gallinaceum.clinical manifestations of malaria infection in vertebrate hosts arise from the multiplication of the asexual stage parasites in the blood, while the gametocytes are responsible for the transmission of the disease. antimalarial drugs that target the blood stage parasites and transmissible gametocytes are rare, but are essentially needed for the effective control of malaria and for limiting the spread of resistance. artemisinin and its derivatives are the current first-line antimalarials that are ...201728043395
vector competence of aedes albopictus (skuse) and aedes aegypti (linnaeus) for plasmodium gallinaceum infection and transmission.avian malaria caused by plasmodium gallinaceum is an important mosquito-borne disease. eradication of this disease remains problematic since its competent vectors are diverse and widely distributed across the globe. several mosquito species were implicated as competent vectors for this parasite. however, studies on vector competence for p. gallinaceum remain limited. in this study, vector competence in the two most predominant mosquito vectors in tropical countries, aedes albopictus and ae. aegy ...201728579025
development of malaria transmission-blocking vaccines: from concept to product.despite decades of effort battling against malaria, the disease is still a major cause of morbidity and mortality. transmission-blocking vaccines (tbvs) that target sexual stage parasite development could be an integral part of measures for malaria elimination. in the 1950s, huff et al. first demonstrated the induction of transmission-blocking immunity in chickens by repeated immunizations with plasmodium gallinaceum-infected red blood cells. since then, significant progress has been made in ide ...201526003037
molecular detection of the avian malaria parasite plasmodium gallinaceum in thailand.avian malaria is one of the most common veterinary problems in southeast asia. the standard molecular method for detection of the avian malaria parasite involves the phenol-chloroform extraction of parasite genomic (g)dna followed by the amplification of parasite gdna using polymerase chain reaction (pcr). however, the phenol-chloroform extraction method is time-consuming and requires large amounts of samples and toxic organic solvents, thereby limiting its applications for parasite detection in ...201525868848
effects of artesunate treatment on plasmodium gallinaceum transmission in the vectors aedes aegypti and culex quinquefasciatus.in the absence of vaccines, chemotherapy is an effective and economical way for controlling malaria. development of anti-malarial drugs that target pathogenic blood stage parasites and gametocytes is preferable for the treatment as it can alleviate the host's morbidity and mortality and block transmission of the plasmodium parasite. recently, our laboratory has developed an in vivo transmission blocking assay that involves administration of 7 consecutive daily doses of a test compound into domes ...201525466617
transcriptome sequencing and analysis of plasmodium gallinaceum reveals polymorphisms and selection on the apical membrane antigen-1.plasmodium erythrocyte invasion genes play a key role in malaria parasite transmission, host-specificity and immuno-evasion. however, the evolution of the genes responsible remains understudied. investigating these genes in avian malaria parasites, where diversity is particularly high, offers new insights into the processes that confer malaria pathogenesis. these parasites can pose a significant threat to birds and since birds play crucial ecological roles they serve as important models for dise ...201425261185
loop-mediated isothermal amplification assay for detection of histomonas meleagridis infection in chickens targeting the 18s rrna sequences.histomonas meleagridis is the causative agent of histomonosis, a disease of gallinaceous fowl characterized by necrotic typhlitis, hepatitis, and high mortality. to develop a rapid and sensitive method for specific detection of h. meleagridis, an assay based on loop-mediated isothermal amplification (lamp) targeting the 18s rrna gene was established. the detection limit of the lamp assay was 10 copies for standard plasmids containing an 18s rrna gene fragment, which was superior to that of a cla ...201424320623
loop-mediated isothermal amplification assay for detection of histomonas meleagridis infection in chickens targeting the 18s rrna sequences.histomonas meleagridis is the causative agent of histomonosis, a disease of gallinaceous fowl characterized by necrotic typhlitis, hepatitis, and high mortality. to develop a rapid and sensitive method for specific detection of h. meleagridis, an assay based on loop-mediated isothermal amplification (lamp) targeting the 18s rrna gene was established. the detection limit of the lamp assay was 10 copies for standard plasmids containing an 18s rrna gene fragment, which was superior to that of a cla ...201324325302
in vivo transmission blocking activities of artesunate on the avian malaria parasite plasmodium gallinaceum.infection and transmission of the avian malaria parasite plasmodium gallinaceum in domestic chickens is associated with high economic burden and presents a major challenge to poultry industry in south east asia. development of drugs targeting both asexual blood stage parasites and sexual stages of the avian malarias will be beneficial for malaria treatment and eradication. however, current drugs recommended for treatment of the avian malaria parasites target specifically the asexual blood stage ...201323937960
chickens treated with a nitric oxide inhibitor became more resistant to plasmodium gallinaceum infection due to reduced anemia, thrombocytopenia and inflammation.malaria is a serious infectious disease caused by parasites of the plasmodium genus that affect different vertebrate hosts. severe malaria leads to host death and involves different pathophysiological phenomena such as anemia, thrombocytopenia and inflammation. nitric oxide (no) is an important effector molecule in this disease, but little is known about its role in avian malaria models. plasmodium gallinaceum-infected chickens were treated with aminoguanidine (ag), an inhibitor of inducible nit ...201323398940
identification and expression of maebl, an erythrocyte-binding gene, in plasmodium gallinaceum.avian malaria is of significant ecological importance and serves as a model system to study broad patterns of host switching and host specificity. the erythrocyte invasion mechanism of the malaria parasite plasmodium is mediated, in large part, by proteins of the erythrocyte-binding-like (ebl) family of genes. however, little is known about how these genes are conserved across different species of plasmodium, especially those that infect birds. using bioinformatical methods in conjunction with p ...201323224610
susceptibility of anopheles stephensi to plasmodium gallinaceum: a trait of the mosquito, the parasite, and the environment.vector susceptibility to plasmodium infection is treated primarily as a vector trait, although it is a composite trait expressing the joint occurrence of the parasite and the vector with genetic contributions of both. a comprehensive approach to assess the specific contribution of genetic and environmental variation on "vector susceptibility" is lacking. here we developed and implemented a simple scheme to assess the specific contributions of the vector, the parasite, and the environment to "vec ...201121694762
blocking of plasmodium transmission by cooperative action of cecropin a and defensin a in transgenic aedes aegypti mosquitoes.to overcome burden of mosquito-borne diseases, multiple control strategies are needed. population replacement with genetically modified mosquitoes carrying antipathogen effector genes is one of the possible approaches for controlling disease transmission. however, transgenic mosquitoes with antipathogen phenotypes based on overexpression of a single type effector molecule are not efficient in interrupting pathogen transmission. here, we show that co-overexpression of two antimicrobial peptides ( ...201020385844
pathogenic action of plasmodium gallinaceum in chickens: brain histology and nitric oxide production by blood monocyte-derived macrophages.plasmodium infection causes major losses to animal and human populations. the characterization of experimental malaria models is needed for a better understanding of disease mechanisms and the development of new treatment protocols. chickens infected with plasmodium gallinaceum constitute an adequate malaria model due to the phylogenetic proximity of this parasite to human plasmodium as well as similarities in disease manifestation, such as cerebral malaria. the aim of the present study was to f ...201020537466
exoerythrocytic development of plasmodium gallinaceum in the white leghorn chicken.plasmodium gallinaceum typically causes sub-clinical disease with low mortality in its primary host, the indian jungle fowl gallus sonnerati. domestic chickens of european origin, however, are highly susceptible to this avian malaria parasite. here we describe the development of p. gallinaceum in young white leghorn chicks with emphasis on the primary exoerythrocytic phase of the infection. using various regimens for infection, we found that p. gallinaceum induced a transient primary exoerythroc ...200818005972
expression of a mutated phospholipase a2 in transgenic aedes fluviatilis mosquitoes impacts plasmodium gallinaceum development.the genetic manipulation of mosquito vectors is an alternative strategy in the fight against malaria. it was previously shown that bee venom phospholipase a2 (pla2) inhibits ookinete invasion of the mosquito midgut although mosquito fitness was reduced. to maintain the pla2 blocking ability without compromising mosquito biology, we mutated the protein-coding sequence to inactivate the enzyme while maintaining the protein's structure. dna encoding the mutated pla2 (mpla2) was placed downstream of ...200818353106
the avian malaria parasite plasmodium gallinaceum causes marked structural changes on the surface of its host erythrocyte.using a combination of atomic force, scanning and transmission electron microscopy, we found that avian erythrocytes infected with the avian malaria parasite plasmodium gallinaceum develop approximately 60 nm wide and approximately 430 nm long furrow-like structures on the surface. furrows begin to appear during the early trophozoite stage of the parasite's development. they remain constant in size and density during the course of parasite maturation and are uniformly distributed in random orien ...200818442920
proteomic analysis of zygote and ookinete stages of the avian malaria parasite plasmodium gallinaceum delineates the homologous proteomes of the lethal human malaria parasite plasmodium falciparum.delineation of the complement of proteins comprising the zygote and ookinete, the early developmental stages of plasmodium within the mosquito midgut, is fundamental to understand initial molecular parasite-vector interactions. the published proteome of plasmodium falciparum does not include analysis of the zygote/ookinete stages, nor does that of p. berghei include the zygote stage or secreted proteins. p. gallinaceum zygote, ookinete, and ookinete-secreted/released protein samples were prepare ...200818563747
ampelozyziphus amazonicus ducke (rhamnaceae), a medicinal plant used to prevent malaria in the amazon region, hampers the development of plasmodium berghei sporozoites.most medicinal plants used against malaria in endemic areas aim to treat the acute symptoms of the disease such as high temperature fevers with periodicity and chills. in some endemic areas of the brazilian amazon region one medicinal plant seems to be an exception: ampelozyziphus amazonicus, locally named "indian beer" or "saracura-mira", used to prevent the disease when taken daily as a cold suspension of powdered dried roots. in previous work we found no activity of the plant extracts against ...200818599059
change of serum transferrin receptor due to malarial infection, an experiment in plasmodium gallinaceum infected chicken model.the serum transferrin receptor (stfr) concentration in an individual reflects the extent of erythropoietic activity and is considered as an useful marker of iron deficiency independent of concurrent inflammation or infection. however, data on the impact of malaria on this parameter are ambiguous.200718092532
laminin and a plasmodium ookinete surface protein inhibit melanotic encapsulation of sephadex beads in the hemocoel of mosquitoes.in refractory mosquitoes, melanotic encapsulation of plasmodium ookinetes and oocysts is a commonly observed immune response. however, in susceptible mosquitoes, plasmodium oocysts develop extracellularly in the body cavity without being recognized by the immune system. like plasmodium gallinaceum oocysts, negatively charged carboxymethyl (cm)-sephadex beads implanted in the hemocoel of aedes aegypti female mosquitoes were not usually melanized, but were coated with mosquito-derived laminin. con ...200717224290
inhibition of malaria parasite blood stages by tyrocidines, membrane-active cyclic peptide antibiotics from bacillus brevis.tyrothricin, a complex mixture of antibiotic peptides from bacillus brevis, was reported in 1944 to have antimalarial activity rivalling that of quinine in chickens infected with plasmodium gallinaceum. we have isolated the major components of tyrothricin, cyclic decapeptides collectively known as the tyrocidines, and tested them against the human malaria parasite plasmodium falciparum using standard in vitro assays. although the tyrocidines differ from each other by conservative amino acid subs ...200717462586
genetic control of malaria parasite transmission: threshold levels for infection in an avian model system.genetic strategies for controlling malaria transmission based on engineering pathogen resistance in anopheles mosquitoes are being tested in a number of animal models. a key component is the effector molecule and the efficiency with which it reduces parasite transmission. single-chain antibodies (scfvs) that bind the circumsporozoite protein of the avian parasite, plasmodium gallinaceum, can reduce mean intensities of sporozoite infection of salivary glands by two to four orders of magnitude in ...200717556613
correlation between serum transferrin receptor and percentage of parasitemia in malaria. a preliminary report.the serum transferrin receptor (stfr) concentration is an individual reflects of the extent of erythropoietic activity, and is a useful marker for monitoring erythropoiesis. malaria is an important tropical disease with evidence of ineffective erythropoiesis. although there have been previous reports concerning stfr changes in malaria, these were descriptive studies of infected and non-infected case and there are no previous reports of correlation between stfr levels and parasitemia in malaria. ...200717645190
avian malaria: clinical and chemical pathology of plasmodium gallinaceum in the domesticated fowl gallus gallus.data on the effects of plasmodium gallinaceum on domesticated fowl are sparse, justifying a full investigation of its pathology. clinical signs following blood-induced infections with the wellcome line of strain 8a included depression, fever, anorexia, reduced weight gain, poor feed conversion, anaemia, green faeces and often death. after administration of 10(6) erythrocytic parasites, mortality 5 to 10 days after infection was 10% to 93% in chickens 7 to 84 days old. the older the birds, the lo ...200515763737
the efficacy of a mixture of trimethoprim and sulphaquinoxaline against plasmodium gallinaceum malaria in the domesticated fowl gallus gallus.the apicomplexan parasite plasmodium gallinaceum has not been much studied from the veterinary standpoint. although it causes malaria in domesticated chickens, no effective drugs appear to be commercially available. a mixture of trimethoprim and sulphaquinoxaline (tmp/sqx, ratio 1:3), with a wide spectrum of activity against bacteria and coccidia, is here shown to be also efficacious against blood-induced p. gallinaceum malaria when administered therapeutically in the feed of chickens for 5-day ...200515845274
plasmodium gallinaceum: clinical progression, recovery, and resistance to disease in chickens infected via mosquito bite.historically, in vivo experiments of plasmodium gallinaceum in chickens have caused high mortality. perhaps because of this high mortality, it remains to be demonstrated whether recovered birds will resist a second episode of illness when re-exposed to infected mosquitoes. in the current study, groups of 10 chicks were infected with p. gallinaceum via mosquito bite. parasitemia and anemia were followed by recovery in all birds, although they had persisting, low levels of parasitized erythrocytes ...200516354820
isonicotinic acid hydrazide: an anti-tuberculosis drug inhibits malarial transmission in the mosquito gut.we studied the transmission-blocking effect of isonicotinic acid hydrazide (inh), a widely used anti-tuberculosis drug, against plasmodium gallinaceum and plasmodium berghei. inh-treatment of infected animals did not inhibit parasite development in the blood of the vertebrate host, but did inhibit exflagellation, ookinete formation, and oocyst development in the mosquito. oocyst development was inhibited in a dose-dependent manner. the ed(50) in the p. gallinaceum/chicken/aedes aegypti model and ...200415013786
preliminary results of an anticircumsporozoite dna vaccine trial for protection against avian malaria in captive african black-footed penguins (spheniscus demersus).captive juvenile african black-footed penguins (spheniscus demersus) housed in an outdoor enclosure at the baltimore zoo have an average 50% mortality from avian malarial (plasmodium sp.) infection each year without intense monitoring for disease and chemotherapeutic intervention. during the 1996 malaria transmission season, the safety and efficacy of an anti-circumsporozoite (csp) dna vaccine encoding the plasmodium gallinaceum csp protein against p. relictum were studied. the goal was to reduc ...200415305509
direct and indirect immunosuppression by a malaria parasite in its mosquito vector.malaria parasites develop as oocysts within the haemocoel of their mosquito vector during a period that is longer than the average lifespan of many of their vectors. how can they escape from the mosquito's immune responses during their long development? whereas older oocysts might camouflage themselves by incorporating mosquito-derived proteins into their surface capsule, younger stages are susceptible to the mosquito's immune response and must rely on other methods of immune evasion. we show th ...200415306308
experimental evaluation of the relationship between lethal or non-lethal virulence and transmission success in malaria parasite infections.evolutionary theory suggests that the selection pressure on parasites to maximize their transmission determines their optimal host exploitation strategies and thus their virulence. establishing the adaptive basis to parasite life history traits has important consequences for predicting parasite responses to public health interventions. in this study we examine the extent to which malaria parasites conform to the predicted adaptive trade-off between transmission and virulence, as defined by morta ...200415355551
effect of the aedes fluviatilis saliva on the development of plasmodium gallinaceum infection in gallus (gallus) domesticus.effect of aedes fluviatilis saliva on the development of plasmodium gallinaceum experimental infection in gallus (gallus) domesticus was studied in distinct aspects. chickens subcutaneously infected with sporozoites in the presence of the mosquito salivary gland homogenates (sgh) showed higher levels of parasitaemia when compared to those ones that received only the sporozoites. however, the parasitaemia levels were lower among chickens previously immunized by sgh or non-infected mosquito bites ...200415654426
the development of plasmodium gallinaceum infections in chickens following single infections with three different dose levels.in the present study, groups of 5-day-old chickens were inoculated intravenously with approximately 10(6), 10(4) or 10(2) p. gallinaceum-infected erythrocytes. the outcome of disease in relation to dose level was evaluated in terms of number of parasitized erythrocytes, change in number of erythrocytes, pathological changes of organs and the course of exo-erythrocytic stages of the parasite in various organs over a period of 8 weeks. mean weight gain and mortality were also recorded. with regard ...200211879962
the effect of plasmodium gallinaceum on a challenge infection with ascaridia galli in chickens.the effect of a primary infection with the haemoparasite plasmodium gallinaceum on the establishment of a challenge infection with the nematode ascaridia galli in chickens was studied. four groups were infected as follows. group 1: inoculated intravenously with 10(6) p. gallinaceum-infected erythrocytes on day 0; group 2: orally infected with 500 embryonated a. galli eggs on day 10; group 3: infected with p. gallinaceum on day 0 and a. galli on day 10; and group 3: non-infected control birds. th ...200211879963
two functionally distinct organic osmolyte pathways in plasmodium gallinaceum-infected chicken red blood cells.red cells infected with the human malaria parasite plasmodium falciparum have an increased permeability to a range of small, structurally unrelated solutes via a malaria-induced pathway. we report here a similar pathway present in parasitised red cells from chickens infected with the avian malaria parasite, plasmodium gallinaceum. parasitised cells showed a marked increase in the rate of influx of sorbitol (76-fold) and, to a lesser degree, taurine (3-fold) when compared with red cells from unin ...200211988184
ecto-, endo- and haemoparasites in free-range chickens in the goromonzi district in zimbabwe.a cross-sectional study determined the prevalence of ecto-, endo- and haemoparasites in free-range chickens from the goromonzi district, zimbabwe. fifty young and 50 adult birds were selected randomly. all chickens harboured ecto- and endoparasites, and 32% were infected with haemoparasites. eight different ectoparasites were identified; the more prevalent ones had the following prevalences (young, %; adult, %): argas persicus (6; 14), cnemidocoptes mutans (6; 32), echidnophaga gallinacea (72; 7 ...200212114010
reduced efficacy of the immune melanization response in mosquitoes infected by malaria parasites.although the mosquito vectors of malaria have an effective immune system capable of encapsulating many foreign particles, they rarely encapsulate malaria parasites in natural populations. a possible reason for this apparent paradox is that infection by malaria reduces the capability of the mosquito to mount an effective immune response. to investigate this possibility, we blood-fed aedes aegypti mosquitoes on an uninfected chicken or on one infected with plasmodium gallinaceum, and compared the ...200212211612
malaria parasite plasmodium gallinaceum up-regulates host red blood cell channels.the properties of the malaria parasite-induced permeability pathways in the host red blood cell have been a major area of interest particularly in the context of whether the pathways are host- or parasite-derived. in the present study, the whole-cell configuration of the patch-clamp technique has been used to show that, compared with normal cells, chicken red blood cells infected by plasmodium gallinaceum exhibited a 5-40-fold larger membrane conductance, which could be further increased up to 1 ...200111434924
the search for new antimalarial drugs from plants used to treat fever and malaria or plants ramdomly selected: a review.in this review we discuss the ongoing situation of human malaria in the brazilian amazon, where it is endemic causing over 610,000 new acute cases yearly, a number which is on the increase. this is partly a result of drug resistant parasites and new antimalarial drugs are urgently needed. the approaches we have used in the search of new drugs during decades are now reviewed and include ethnopharmocology, plants randomly selected, extracts or isolated substances from plants shown to be active aga ...200111784919
a snake venom phospholipase a(2) blocks malaria parasite development in the mosquito midgut by inhibiting ookinete association with the midgut surface.oocyst formation is a critical stage in the development of the malaria parasite in the mosquito. we have discovered that the phospholipase a(2) (pla2) from the venom of the eastern diamondback rattlesnake (crotalus adamanteus) inhibits oocyst formation when added to infected chicken blood and fed to mosquitoes. a similar transmission-blocking activity was demonstrated for pla2s from the venom of other snakes and from the honeybee. this effect is seen both with the avian malaria parasite plasmodi ...200111809789
3' utr elements enhance expression of pgs28, an ookinete protein of plasmodium gallinaceum.in plasmodium parasites the fusion of gametes to form a fertilized zygote and morphogenesis into the motile ookinete are critical developmental stages in the parasite's complex life cycle. in analogous developmental stages of metazoan organisms 3' gene flanking regions are critical in the regulation of gene expression. to determine whether these mechanisms are conserved in the protozoan parasite we studied the 3' gene flanking elements necessary for the expression of pgs28, the major surface pro ...200010613699
chitinases of the avian malaria parasite plasmodium gallinaceum, a class of enzymes necessary for parasite invasion of the mosquito midgut.the plasmodium ookinete produces chitinolytic activity that allows the parasite to penetrate the chitin-containing peritrophic matrix surrounding the blood meal in the mosquito midgut. since the peritrophic matrix is a physical barrier that the parasite must cross to invade the mosquito, and the presence of allosamidin, a chitinase inhibitor, in a blood meal prevents the parasite from invading the midgut epithelium, chitinases (3.2.1.14) are potential targets of malaria parasite transmission-blo ...200010744721
sex ratio adjustment in plasmodium gallinaceum.the sex ratio of the avian malaria parasite, plasmodium gallinaceum, was examined during the course of infection in its natural host, the chicken. infections can have two possible outcomes: death of the host resulting from anaemia or self-cure and survival. in lethal infections the sex ratio remained female biased throughout, whereas in self-curing infections, the sex ratio became progressively less female biased. we examined the consequences of altering sex ratio for parasite transmission succe ...199910697848
controlling malaria transmission with genetically-engineered, plasmodium-resistant mosquitoes: milestones in a model system.we are developing transgenic mosquitoes resistant to malaria parasites to test the hypothesis that genetically-engineered mosquitoes can be used to block the transmission of the parasites. we are developing and testing many of the necessary methodologies with the avian malaria parasite, plasmodium gallinaceum, and its laboratory vector, aedes aegypti, in anticipation of engaging the technical challenges presented by the malaria parasite, p. falciparum, and its major african vector, anopheles gam ...199910697903
effect of bacillus thuringiensis ssp. israelensis on the development of plasmodium gallinaceum in aedes aegypti (diptera: culicidae).adult, female aedes aegypti, some of which had survived a sublethal dose (lc50) of bacillus thuringiensis ssp. israelensis (bti) as larvae, were fed on chickens with gametocytaemia of plasmodium gallinaceum. parasite development was monitored by dissecting samples of the mosquitoes immediately after the feed and on days 1, 7 and 9 post-feed, to check for the presence of gametocytes, ookinetes, oocysts and sporozoites, respectively. as the proportions of batches of fed mosquitoes found positive f ...199910492676
plasmodium gallinaceum: fluorescent staining of zygotes and ookinetes to study malaria parasites in mosquito.we have developed a fluorescent labeling procedure for staining the mosquito stages of plasmodium gallinaceum. pkh26, a lipophilic dye, is efficiently and permanently incorporated into the membranes of zygotes and ookinetes. stained zygotes undergo normal development into ookinetes; the stain does not interfere with ookinete mobility or ability to adhere to the mosquito midgut lumen. stained zygotes and ookinetes are comparable to untreated parasites in their ability to give rise to oocysts when ...19989538861
plasmodium gallinaceum: effect of insect cells on ookinete development in vitro.in vitro culture conditions affecting the transformation efficiency from zygote to ookinete for plasmodium gallinaceum were examined, as a step toward improving the overall efficiency of in vitro culture systems for sporogonic stages. gametocytes from infected chickens were allowed to fertilize in vitro and the resulting zygotes were purified and cultured. the time course for ookinete development in vitro was similar to that seen in aedes aegypti mosquitoes. supplementing a basal m-199 culture m ...19989562424
xanthurenic acid induces gametogenesis in plasmodium, the malaria parasite.a small, heat stable chromophore extracted from mosquitoes has recently been implicated as the signal that induces mating of plasmodium, the malaria parasite. we have used high resolution electrospray mass spectrometry to determine that this gamete activation factor (gaf) has a m/z = 205.0450, suggesting a molecular species composition of c10h7no4. xanthurenic acid (xa), a product of tryptophan catabolism, was determined to have an elemental composition, ultraviolet absorbance maxima, and mass s ...19989575140
adherence of erythrocytes during exflagellation of plasmodium falciparum microgametes is dependent on erythrocyte surface sialic acid and glycophorins.malaria male gametocytes within a newly ingested infected blood meal in the mosquito midgut emerge from erythrocytes and extrude approximately eight flagellar microgametes in a process termed exflagellation. in culture, and in blood removed from infected patients, emerging microgametes avidly adhere to neighboring uninfected and infected erythrocytes, as well as to emerged female macrogametes, creating "exflagellation centers". the mechanism of erythrocyte adherence is not known nor has it been ...19989584138
antisporozoite antibodies with protective and nonprotective activities: in vitro and in vivo correlations using plasmodium gallinaceum, an avian model.a correlation was observed between in vivo and in vitro activity of six monoclonal antibodies (mab) against the major circumsporozoite protein of the avian malaria plasmodium gallinaceum as follows. (1) two mab were protective, totally abrogating sporozoite infectivity to chicks, its natural host, in vivo; they caused 100% inhibition of sporozoite invasion (isi) in vitro to sl-29 chicken fibroblasts and intense isi to cultured chicken macrophages, as well as inhibited the exoerythrocytic develop ...19958520586
unique specificity of in vitro inhibition of mosquito midgut trypsin-like activity correlates with in vivo inhibition of malaria parasite infectivity.synchrony in the egress of plasmodium ookinetes from the food bolus and enzymatic digestion of the blood meal in the mosquito midgut suggests that digestive enzymes play a role in the successful transmission of malaria parasites. previously, we found that parasite-produced chitinase is essential for parasite transmission and can be activated by mosquito midgut protease. to determine the suitability of developing a transmission-blocking vaccine directed against mosquito trypsin-like enzyme(s), ae ...19957534722
the journey of malaria sporozoites in the mosquito salivary gland.the life cycle of malaria parasites in the mosquito vector is completed when the sporozoites infect the salivary gland and are ready to be injected into the vertebrate host. this paper describes the fine structure of the invasive process of mosquito salivary glands by malaria parasites. plasmodium gallinaceum sporozoites start the invasion process by attaching to and crossing the basal lamina and then penetrating the host plasma membrane of the salivary cells. the penetration process appears to ...19947866385
plasmodium gallinaceum: differential lysis of two developmental stages of malaria sporozoites by the alternative pathway of complement.during sporogonic development of plasmodium gallinaceum in the mosquito vector, two developmentally distinct sporozoite stages can be isolated. sporozoites obtained from oocysts in abdomens of mosquitoes 10 days after an infective blood meal are poorly infectious to the vertebrate host (chicken); days later, sporozoites isolated from mosquito salivary glands are highly infectious. in a first step toward understanding the physiologic basis of this developmentally regulated infectivity to the vert ...19948162961
exoerythrocytic development of plasmodium gallinaceum sporozoites in a chicken fibroblast cell line and inhibition of the cell invasion by specific anti-sporozoite monoclonal antibodies.cultivation of the plasmodium gallinaceum exoerythrocytic forms from sporozoites was attempted in three different cell lines: hepg2-a16 (from a human hepatoma), vero (monkey kidney epithelial cells) and sl-29 (chicken embryo fibroblast cells). the sporozoites invaded all three cells types but their development into exoerythrocytic forms occurred only in the sl-29 cells. in the presence of specific monoclonal antibodies against the major circumsporozoite protein, there were varying degrees of inh ...19938457801
transmission-blocking activity of a chitinase inhibitor and activation of malarial parasite chitinase by mosquito protease.during development in the mosquito midgut, malarial parasites must traverse a chitin-containing peritrophic matrix (pm) that forms around the food bolus. previously huber et al. [huber, m., cabib, e. & miller, l. h. (1991) proc. natl. acad. sci. usa 88, 2807-2810] reported that the parasite secretes a protein with chitinase activity, and they suggested that parasite chitinase (ec 3.2.1.14) plays an important role in the parasite's egress from the blood meal. we found that allosamidin, a specific ...19938483942
a method for screening drugs against the liver stages of malaria using plasmodium gallinaceum and aedes mosquitos.1. the radical cure of human malaria caused by plasmodium vivax requires two drugs, i.e., a blood schizontocide such as chloroquine to clear the circulating parasites, and primaquine aimed at the liver stages (hyponozoites) responsible for the late relapses of this parasite. primaquine is unique as a radical curative drug but is highly toxic. the only useful model currently available for screening drugs to replace primaquine is plasmodium cynomolgi-induced malaria in rhesus monkeys. because of t ...19921341921
developmentally regulated infectivity of malaria sporozoites for mosquito salivary glands and the vertebrate host.sporozoites are an invasive stage of the malaria parasite in both the mosquito vector and the vertebrate host. we developed an in vivo assay for mosquito salivary gland invasion by preparing plasmodium gallinaceum sporozoites from infected aedes aegypti mosquitoes under physiological conditions and inoculating them into uninfected female ae. aegypti. sporozoites from mature oocysts were isolated from mosquito abdomens 10 or 11 d after an infective blood meal. salivary gland sporozoites were isol ...19921588284
in vitro development of exoerythrocytic forms of plasmodium gallinaceum sporozoites in avian macrophages.exoerythrocytic forms of plasmodium gallinaceum were cultured in vitro using salivary gland sporozoites extracted from experimentally infected aedes fluviatilis mosquitoes. the host cells were macrophage precursors from chicken bone marrow. at various times after introduction of sporozoites, the cultures were stained by giemsa or by immunofluorescence assay (ifa) using anti-sporozoite-specific monoclonal antibodies (mab). the time to complete parasite development in vitro was 50-70 h. by 70 h, r ...19911997676
[the relationship between the amount of blood that mosquitoes engorge and their infectivity with the causative agent of malaria].the infection of mosquitoes with malaria plasmodia was found to be affected by relative (to full portion) blood amount of the infected donor, which they suck out, i.e. to what extent the engorged portion approximates to the limiting one when mosquitoes cease bloodsucking. the facts obtained show that the survival of plasmodia in a mosquito (most likely, the passing of ookinetes into the outer side of the mid-gut) is associated with the degree of its stretching during bloodsucking. the limit stre ...19902099999
[further comment on the role of sugars for the successful infection of blood-sucking diptera by protozoa that are the causative agents of human diseases].possible reasons of a successful development of plasmodium gallinaceum in aedes aegypti, which were not given sugar feeding, are analysed. such reasons are assumed to be high contents of sugars (up to 200 mg/% in the blood of chickens-donors) and retention of sugar in the crop of mosquitoes, which were fed from a tampon, in control.19902259528
transmission of plasmodium gallinaceum by adult aedes aegypti infected as larvae.transmission of plasmodium gallinaceum to chickens by adult mosquitoes eclosed from larvae that consumed infected adult mosquitoes was investigated. no malarial infections were observed in chicks fed on by mosquitoes that eclosed from larvae that had consumed crushed infected adult mosquitoes. where cadavers with noncrushed thoraces were used, 3 of 4 chicks fed on by adult mosquitoes developed parasitemias ranging from 6 to 11% infected erythrocytes.19902324722
circumsporozoite protein of plasmodium gallinaceum characterized by monoclonal antibodies.monoclonal antibodies (moab) were produced against both salivary gland sporozoites (sgs) and oocyst sporozoites (os) of plasmodium gallinaceum, an avian malaria parasite. by indirect immunofluorescence, all of the moabs reacted with both sgs and os of p. gallinaceum and two of the moabs cross-reacted weakly with p. berghei sporozoites. none of the moabs reacted with sporozoites of six additional species of mammalian plasmodia. in western blot analysis of extracts of either sgs or os of p. gallin ...19882461541
complement effects of the infectivity of plasmodium gallinaceum to aedes aegypti mosquitoes. ii. changes in sensitivity to complement-like factors during zygote development.during transformation into ookinetes, the zygotes of plasmodium gallinaceum are initially resistant to lysis by heat-labile and edta-sensitive factors in the serum of their natural host, the chicken. between 6 and 8 hr postgametogenesis, zygotes cultured in vitro lose their resistance to these factors. loss of resistance to these factors in vitro is reflected by loss of infectivity of the zygotes to aedes aegypti mosquitoes in the presence of native chicken serum. these factors are probably comp ...19873116195
complement effects on the infectivity of plasmodium gallinaceum to aedes aegypti mosquitoes. i. resistance of zygotes to the alternative pathway of complement.gametocytes are the intraerythrocytic stages of malaria parasites that infect mosquitoes. when gametocytes of the chicken malaria parasite plasmodium gallinaceum are ingested by a mosquito they become extracellular in the mosquito midgut, form gametes, and fertilize within 10 to 15 min after the insect has taken a blood meal. gametocytes of p. gallinaceum were infectious when fed to aedes aegypti mosquitoes in blood meals containing native serum from chickens or from the non-host species, man or ...19863517168
plasmodium gallinaceum: sporozoite activity in immune mosquito hemolymph.sporozoites of plasmodium gallinaceum are relatively inactive in hanks' balanced salt solution or in the hemolymph of the susceptible aedes aegypti mosquito. they become agitated and very active in the presence of the hemolymph of the innately immune mosquito, culex pipiens. sporozoites from the latter are more infective in chicks than the former. this behavior is likely the result of stimulation or irritation by the adverse environment.19853972059
does plasmodium gallinaceum induce relapse of eimeria acervulina infection in chickens?an experiment was carried out to test the hypothesis that chickens previously infected with eimeria acervulina, but having ceased producing oocysts, recommence e acervulina oocyst production when infected with plasmodium gallinaceum. no relapse of coccidiosis was caused by the malarial infection. subsequent treatment with the immunosuppressant betamethasone of the control chicks infected with e acervulina only did not reveal any occult coccidial infection. the results are critically compared wit ...19854070797
plasmodium gallinaceum and subsequent eimeria acervulina infections in chickens are not synergistic.twenty-three years age, the first and only report of synergism between malarial and coccidial infections in chickens was published. in view of the potential commercial importance of this possible parasitic interaction in some parts of the world, and the lack of further supporting publications, this disease complex has now been reconsidered. an experiment on plasmodium gallinaceum and eimeria acervulina revealed no interaction of any kind between these species and a re-examination, with statistic ...198520821868
biliverdin production in chickens infected with the malarial parasite plasmodium gallinaceum.chickens infected with the malarial parasite plasmodium gallinceum produced green droppings: the predominant pigment was biliverdin. droppings of identical appearance were produced by chicks injected with phenylhydrazine, a haemolytic agent: it is concluded that the catabolism of haemoglobin resulting at least in part from malarial haemolysis produces excess bile pigments which appear in the droppings. other chicken diseases in which green droppings are "a characteristic objective symptom are fo ...198518766933
plasmodium gallinaceum: density dependent limits on infectivity to aedes aegypti.in acute, blood-induced infections of chickens, the malarial parasite plasmodium gallinaceum is most infective to the mosquito aedes aegypti 1 day before gametocyte numbers peak. in an effort to account for this disynchrony , daily changes in parasite infectivity, parasitemia, hematocrit, and hemoglobin were measured during the course of infections. three events were correlated with the loss of infectivity: (1) in the 24 hr between park infectivity and peak gametocytemia , schizont-induced hemol ...19846723894
plasmodium gallinaceum: avian screen for drugs with radical curative properties.existing primary screens for radical curative antimalarial drugs fail to adequately detect many compounds which affect the latent, exoerythrocytic hypnozoite, the stage of the parasite responsible for relapse. at the same time, these screens falsely identify a wide range of compounds with no radical curative activity. the avian malaria, plasmodium gallinaceum, and aedes aegypti mosquitos were used in a screen which measures the effects of candidate compounds on gametocytes and their development ...19836832279
monoclonal antibodies against surface determinants on gametes of plasmodium gallinaceum block transmission of malaria parasites to mosquitoes.monoclonal antibodies (mab) against gametes of the chicken malaria plasmodium gallinaceum have been derived. all reacted with the surface of extracellular gametes of the parasite in immunofluorescent antibody reactions and all agglutinated both male and female gametes. in the absence of active complement one mu isotype mab, la 1-d5, mediated at least 95% suppression of infectivity of the parasites to aedes aegypti mosquitoes. individually, mab of the gamma 1 or gamma 2a isotypes mediated only sl ...19836631012
characterization of antigens on mosquito midgut stages of plasmodium gallinaceum. i. zygote surface antigens.we have defined the surface protein antigens on plasmodium gallinaceum zygotes using radioiodination methods and rabbit anti-zygote serum which blocks transmission of the parasite to aedes aegypti mosquitoes. fifteen protein bands (1-15) in the molecular weight range of 40 000-240 000 and one band at the bromophenol blue dye marker were labelled by the lactoperoxidase and iodogen (1,3,4,6-tetrachloro-3 alpha,6 alpha-diphenylglycoluril) methods. the localization of these radioiodinated components ...19836683783
immunity to plasmodium chabaudi adami in the b-cell-deficient mouse.immunity to malaria has a multicomponent basis which requires the participation of both t- and b-lymphocyte systems. previous studies have suggested that the t-lymphocyte system has an essential role in 're-infection immunity' to malaria, but that b cells and/or their products are necessary for the host to survive acute infection and to clear the blood of parasites during chronic malaria. thus, b-cell-deficient mice and chickens died of fulminant malaria when infected with plasmodium yoelii and ...19816970898
infectivity of plasmodium gallinaceum sporozoites from oocysts.infectivity of plasmodium gallinaceum (brumpt) sporozoites isolated from midguts and salivary glands of experimentally infected aedes fluviatilis (lutz) was studied. the 2 populations were compared at 7, 8, and 9 days postisolation from mosquitoes, which were maintained at 27 c +/- 1 c and approximately 75% relative humidity. infectivity of the parasites was evaluated by the length of the prepatent period of the infection in 2-week-old chicks inoculated intramuscularly. infection was caused by 7 ...19807218185
vaccination of chicks against plasmodium gallinaceum by erythrocytic and exoerythrocytic parasites attenuated by gamma irradiation.plasmodium gallinaceum-infected blood which received up to 24 krad during exposure to gamma-rays from a cobalt-60 source produced infections of normal course and duration when injected into chickens. the prepatent period advanced with increasing exposure of infected blood to radiation, suggesting some degree of attenuation. at 26, 28 and 30 krad, the infections were transient and the parasites were morphologically abnormal. it is thought that the amount of radiation required to render the parasi ...19807436597
anti-gamete monoclonal antibodies synergistically block transmission of malaria by preventing fertilization in the mosquito.experiments from our laboratory previously demonstrated that infected chickens immunized with gametes of the avian malaria parasite plasmodium gallinaceum were no longer infectious to the mosquito vector aedes aegypti and that this transmission-blocking immunity was mediated by antibody. to identify those antigens that are the targets of transmission-blocking immunity, hybrid mouse cell lines secreting monospecific antibodies to surface antigens on male and female gametes of p. gallinaceum have ...19806935685
variations in the virulence of plasmodium gallinaceum for avian embryos after repeated passages in mosquitos and chickens.inoculation of 1 x 10(6) parasites of plasmodium gallinaceum from chicks infected with sporozoites into 10-day chicken embryos produced infections with wide ranges of peak parasitaemia. it is thought that these variations reflect alterations in the genetic moiety of the parasites after recombinations occurring during the sexual cycle in different batches of mosquitos.197944488
plasmodium gallinaceum-parasitized chicken erythrocytes in a practical hemagglutination test for igm antibodies in human malaria.a new hemagglutination test for human malaria, done with plasmodium gallinaceum-parasitized, aldehyde-fixed, chicken erythrocytes as a stable lyophilized reagent, is described. the test was positive in every human case of falciparum or vivax malaria in which there was parasitemia. it detected only igm anti-plasmodial antibodies and usually became negative within a few weeks after treatment. as a practical and sensitive test for active malaria, the p. gallinaceum hemagglutination test should be c ...1979380370
plasmodium gallinaceum: transmission-blocking immunity in chickens. i. comparative immunogenicity of gametocyte- and gamete-containing preparations. 1979437016
plasmodium gallinaceum: transmission-blocking immunity in chickens. ii. the effect of antigamete antibodies in vitro and in vivo and their elaboration during infection. 1979556175
aedes fluviatilis (lutz), a new experimental host for plasmodium gallinaceum brumpt. 1978722461
gamete development in malaria parasites: bicarbonate-dependent stimulation by ph in vitro.gametogenesis in plasmodium gallinaceum involves bicarbonate-dependent processes and requires a continuous supply of glucose (presumably as an energy source). emergence and exflagellation of gametocytes, in vitro, occur independently of the co2 tension but are rigidly correlated with the ph of the external medium. in bicarbonate-saline gametogenesis is initiated only if the ph exceeds 7.7. our results suggest that gamete development of malaria parasites is stimulated when infected blood is expos ...197823512
plasmodium gallinaceum: induction of male gametocyte exflagellation by phosphodiesterase inhibitors. 197826586
folate antagonists. 10. synthesis and antimalarial effects of 6-[[(aryl and aralkyl)amino]methyl]-2,4-pteridinediamines and -pteridinediamine 8-oxides.various 6-[[(aryl and aralkyl)amino]methyl]-2,4-pteridinediamines and their 8-oxides have been synthesized for antimalarial evaluation. condensation of 3-amino-6-(bromomethyl)-2-pyrazinecarbonitrile 4-oxide (v) with the appropriately substituted amine afforded a series of 3-amino-6-[[(aryl and aralkyl)amino]methyl]-2-pyrazinecarbonitrile 4-oxides vi. deoxygenation gave the corresponding pyrazines vii. cyclization of vi and vii with guanidine then produced the desired 6-(aminomethyl)-2,4-pteridin ...1978349157
plasmodium gallinaceum: changing virulence patterns of malaria parasites during adaptation from neonate chick to chicken embryos. 1977891706
plasmodium gallinaceum: vaccination in chickens. 1977891707
successful immunization against the sexual stages of plasmodium gallinaceum.gametocyte infectivity and oocyst development of the avian malaria parasite, plasmodium gallinaceum, can be reduced or eliminated in mosquitoes by immunizing the chickens on which the mosquitoes feed with infected red blood cells that have been treated with formalin or x-rays. protection of the mosquito appears to be related to the immobilization of the microgametes in its gut and is associated with the immunoglobulin g fraction of serum.1976959832
plasmodium gallinaceum: response of malarious chicken embryos to injection of serum from hyperimmunized chickens. 19761253887
fine structure of plasmodium gallinaceum in embryonic and neonate chicks.the erythrocytic stages of plasmdoium gallinaceum in chicken embryos injected with parasited blood either from a syringe-passaged infection in chickens or from a chicken infected with sporozoites were characterized by abnormal structure. particularly evident were large, unstained vacuoles within the cytoplasm; these occurred with greatest frequency in schizonts. the presence of myelin bodies within these vacuoles was revealed by transmission electron microscopy; abnormal cytokinesis and aberrant ...19761271304
immunosuppressive effects of experimental infection with plasmodium gallinaceum.experimental infection of chickens with p. gallinaceum mardedly suppressed the splenic pfc response to srbc. suppression was most pronounced when birds were immunized at the time of peak parasitemia. the pfc response to e. coli lps was of low magnitiude in both normal and infected chickens; however, it, too, was suppressed in infected birds, but not to the same degree as observed in response to srbc. cellular immunity as evidenced by allograft rejection was not influenced by infection.19751093192
pathogenesis of acute avian malaria. iv. immunologic factors in nephritis of acute plasmodium gallinaceum infections of chickens.study of urinary waste of chickens with acute plasmodium gallinaceum malaria indicated that serum proteins of the globulin and albumin classes were passed. protein extravasation did not begin until globulin-associated serum antigen and its antibody were detected in the blood. both serum antigen and antibody were found in the wastes for as long as the antigen was present in the blood. extracts of kidney tissues contained serum proteins that were not present in extracts from normal kidneys, and se ...19751098493
pathogenesis of acute avian malaria. iii. antigen and antibody complexes as a mediator of anemia in acute plasmodium gallinaceum infections of chickens.in a study of antigens and antibodies found in malarious chicken blood, antigen activity was found in plasma, and in hypertonic saline eluates of blood cells. a soluble antigen was extracted from parasites liberated from erythrocytes. two classes of antigen were differentiated, one a globulin associated "serum antigen" which was found to show identity with a serum antigen from blood of rats with acute babesia rodhaini infection, and another that was associated with the plasmodium gallinaceum par ...1975125550
pathogenesis of acute avian malaria. ii. anemia mediated by a cold-active autohemagglutinin from the blood of chickens with acute plasmodium gallinaceum infection.a cold-active hemagglutinin for trypsinized human type "o" erythrocytes (cah) from blood of chickens with acute plasmodium gallinaceum malaria was found to be associated with 19 s and 7 s globulin fractions of malarious chicken blood, but cleavage with 2-mercaptoethanol indicated that it was primarily of the igm class of antibody. in serologic tests cah reacted with trypsinized erythrocytes, and anti-chicken globulin. it did not react with other of the antigens or antibodies detected in the bloo ...1975804265
the relationship of erythrocyte age and parasitization with plasmodium gallinaceum in chickens.erythrocyte labeling by random and cohort techniques was used to study erythrocyte survival in normal chickens and in chickens infected with plasmodium gallinaceum. white leghorn chickens, eight weeks of age, were used in this series of experiments. in chickens given p. gallinaceum on the day following erythrocyte labeling there was destruction of labeled erythrocytes at a much more rapid rate than would result from normal ageing processes. chickens given p. gallinaceum 12, 18 and 21 days after ...19744279757
antimalarial quinones for prophylaxis based on a rationale of inhibition of electron transfer in plasmodium.knowledge of the biochemistry of plasmodium is emerging as a new field. previous studies showed that the parasite apparently requires electron transfer for energy, and techniques to study such energy mechanisms are available. the discovery of the existence of coenzyme q(8) in plasmodium implies an indispensable functionality for this redox entity in the electron transfer of the parasite, as coenzyme q(n) similarily functions in other forms of life. effective antimalarial activity in prophylaxis ...19744595578
pathogenesis of acute avian malaria. i. immunologic reactions associated with anemia, splenomegaly, and nephritis of acute plasmodium gallinaceum infections of chickens. 19744847038
plasmodium gallinaceum: mechanisms of anemia in infected chickens. 19734691929
physical separation of three soluble malarial antigens from the serum of chickens infected with plasmodium gallinaceum. 19714996704
the differential effect of plasmodium gallinaceum on the fecundity of several strains of aedes aegypti. 19715151912
antibody coating on erythrocytes of chickens infected with plasmodium gallinaceum. 19705473250
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