RESUMO
There is now a growing body of evidence that challenges the current view that Plasmodium vivax-infected erythrocyte (Pv-iE) are unable to sequester. Here we used ex vivo adhesion assays with Pv-iE before and after maturation to demonstrate a higher binding potential of schizonts compared to other asexual stages. These experimental results are correlated with our observations in a panel of 50 vivax malaria patients where schizonts were completely absent in 27 isolates, and few schizonts were observed in the remaining patients. These observations prompt a paradigm shift in P. vivax biology and open avenues to investigate the role of Pv-iE sequestration.
Assuntos
Adesão Celular/fisiologia , Eritrócitos/parasitologia , Malária Vivax/sangue , Malária Vivax/parasitologia , Plasmodium vivax/fisiologia , Antimaláricos/uso terapêutico , Cloroquina/uso terapêutico , Humanos , Malária Vivax/tratamento farmacológico , Parasitemia/sangue , Parasitemia/parasitologia , Plasmodium vivax/crescimento & desenvolvimento , Primaquina/uso terapêutico , Esquizontes/fisiologia , Estatísticas não ParamétricasRESUMO
This study investigated the occurrence of the protozoan Perkinsus in the oyster Crassostrea rhizophorae on the coast of Bahia State, Brazil. The oysters (n = 900) were collected in February-March and July-August 2010. The Ray's fluid thioglycollate medium (RFTM) analysis of gills and rectum revealed hypnospores of Perkinsus sp. with a high mean prevalence (63%). The infection intensity varied from very light to advanced. The polymerase chain reaction confirmed Perkinsus in 87.2% of the RFTM-positive oysters. Histological analysis showed trophozoites and schizonts phagocytized by hemocytes, mainly in the intestine and the stomach epithelium.