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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The squirrel monkey, Saimiri sciureus, is a useful experimental host for the human malaria parasite Plasmodium falciparum. Twelve strains of P. falciparum, including monkey-adapted strains, culture-derived strains, and one human isolate were injected into naive, splenectomized Saimiri monkeys of karyotype 14-7. Several parameters were recorded following inoculation such as parasitemia, body temperature, standard hematological parameters, gametocytemia, rosette formation, autoagglutination, as well as HRPI and PfEMP3 expression. Each strain was injected into two to four monkeys and induced a reproducible course of infection. Four distinct patterns of parasite development were observed. For each strain, a multilocus genotype was established by PCR using several polymorphic (Pf60, RESA, RESA2, MSA1, MSA2, Pf332, TRAP, GLURP, CSP, and HRPI) or conserved (EBA175, GARP, MDRI, and RNA POL III) markers. RFLP analysis was conducted for the Pf11.1 locus. This genotyping approach showed that 3 strains presented strictly similar patterns, typical of FUP/SP parasites. A group of 7 other strains presented a highly similar FUP/CP (FCR3-like) genetic background, while 4 other strains showed unique patterns. Infectiousness did not depend on a RESA deletion, as several strains developed successfully while present ng a wild-type RESA gene. Conversely, an interesting correlation was found between allelic diversity at the HRPI locus and the course of blood stage infection. The data presented here provide the first precise genotyping of several monkey-adapted strains, allowing a more rational approach in the study of the role of parasite diversity on host/parasite interactions.
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PMID:Plasmodium falciparum: genetic diversity of several strains infectious for the squirrel monkey (Saimiri sciureus). 888 29

Knowledge of vector distribution is important for the design of effective local malaria control programs. Here we apply ecological niche modeling to analyze and predict the distributions of malaria vectors based on entomological collection points in the State of Roraima in the northern Brazilian Amazon Basin. Anopheline collections were conducted from 1999 to 2003 at 76 localities, all with active malaria transmission. A total of 13 anopheline species was identified from 17,074 adult females collected: Anopheles darlingi, An. albitarsis s.l., An. nuneztovari, An. triannulatus s.l., An. braziliensis, An. peryassui, An. oswaldoi s.l., An. mattogrossensis, An. strodei, An. evansae, An. squamifemur, An. mediopunctatus s.l, An. intermedius. Anopheles darlingi, and An. albitarsis were the most frequently found species. An. squamifemur was found for the first time in Roraima. A distributional prediction model (genetic algorithm for rule-set prediction-GARP) and environmental variables were used to predicted potential distribution range for six anopheline species that occurred at > or = 19 collection points. The method allows for the application of moderate sample sizes to produce distribution maps of vector species that could be used to maximize efficiency of surveys and optimize use of economic resources in epidemiology and control.
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PMID:Distribution summaries of malaria vectors in the northern Brazilian Amazon. 1826 May 3

Repetitive low complexity sequences, mostly assumed to have no function, are common in proteins that are exported by the malaria parasite into its host erythrocyte. We identify a group of exported proteins containing short lysine-rich tandemly repeated sequences that are sufficient to localize to the erythrocyte periphery, where key virulence-related modifications to the plasma membrane and the underlying cytoskeleton are known to occur. Efficiency of targeting is dependent on repeat number, indicating that novel targeting modules could evolve by expansion of short lysine-rich sequences. Indeed, analysis of fragments of GARP from different species shows that two novel targeting sequences have arisen via the process of repeat expansion in this protein. In the protein Hyp12, the targeting function of a lysine-rich sequence is masked by a neighboring repetitive acidic sequence, further highlighting the importance of repetitive low complexity sequences. We show that sequences capable of targeting the erythrocyte periphery are present in at least nine proteins from Plasmodium falciparum and one from Plasmodium knowlesi We find these sequences in proteins known to be involved in erythrocyte rigidification and cytoadhesion as well as in previously uncharacterized exported proteins. Together, these data suggest that expansion and contraction of lysine-rich repeats could generate targeting sequences de novo as well as modulate protein targeting efficiency and function in response to selective pressure.
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PMID:Expansion of Lysine-rich Repeats in Plasmodium Proteins Generates Novel Localization Sequences That Target the Periphery of the Host Erythrocyte. 2777 5