RESUMO
Molecular tools to distinguish strains of Plasmodium vivax are important for studying the epidemiology of malaria transmission. Two sets of markers-tandem repeat (TR) polymorphisms and MSP3α-were used to study Plasmodium vivax in patients in the Peruvian Amazon region of Iquitos. Of 110 patients, 90 distinct haplotypes were distinguished using 9 TR markers. An MSP3α polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using HhaI and AluI revealed 8 and 9 profiles, respectively, and 36 profiles when analyzed in combination. Combining TR and PCR-RFLP markers, 101 distinct molecular profiles were distinguished among these 110 patients. Nine TR markers arrayed along a 100 kB stretch of a P. vivax chromosome containing the gene for circumsporozoite protein showed non-linear linkage disequilibrium (I(SA) = 0.03, P = 0.001). These findings demonstrate the potential use of TR markers for molecular epidemiology studies.
Assuntos
DNA de Protozoário/genética , Malária Vivax/epidemiologia , Plasmodium vivax/genética , Polimorfismo Genético , Proteínas de Protozoários/genética , Sequências de Repetição em Tandem/genética , Marcadores Genéticos , Haplótipos , Humanos , Desequilíbrio de Ligação , Malária Vivax/transmissão , Peru/epidemiologia , Plasmodium vivax/crescimento & desenvolvimento , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNARESUMO
Anopheles darlingi is the most important malaria vector in the Amazon basin of South America, and is capable of transmitting both Plasmodium falciparum and P. vivax. To understand the genetic structure of this vector in the Amazonian region of Peru, a simple polymerase chain reaction (PCR)-based test to identify this species of mosquito was used. A random amplified polymorphic DNA-PCR was used to study genetic variation at the micro-geographic level in nine geographically separate populations of An. darlingi collected in areas with different degrees of deforestation surrounding the city of Iquitos. Within-population genetic diversity in nine populations, as quantified by the expected heterozygosity (H(E)), ranged from 0.27 to 0.32. Average genetic distance (F(ST)) among these populations was 0.017. These results show that the nine studied populations are highly homogeneous, suggesting that strategies can be developed to combat this malaria vector as a single epidemiologic unit.
Assuntos
Anopheles/genética , Variação Genética , Genética Populacional , Insetos Vetores/genética , Reação em Cadeia da Polimerase/métodos , Animais , Anopheles/classificação , Primers do DNA/química , Feminino , Geografia , Heterozigoto , Insetos Vetores/classificação , Peru , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Sensibilidade e Especificidade , ÁrvoresRESUMO
Identification of species of human tapeworms is crucial because the consequences of infection by Taenia solium and T saginata are very different. However, evacuation of species-identifiable tapeworms is uncommon and Taenia spp eggs are indistinguishable under the microscope. Treatment of taeniasis consists of niclosamide followed by a purgative. Recently, we adopted preniclosamide and postniclosamide electrolyte-polyethyleneglycol salt (EPS) purges to improve bowel cleaning. Retrospective comparison of traditional castor oil with EPS purge showed that recovery of the tapeworm scolex was significantly improved (20 of 68 vs none of 46, p=0.0001) in the EPS group. Furthermore, 42 of 68 (62%) individuals receiving EPS excreted identifiable gravid proglottids. EPS treatment helps the visual identification of Taenia spp.
Assuntos
Taenia saginata/isolamento & purificação , Taenia solium/isolamento & purificação , Teníase/tratamento farmacológico , Teníase/parasitologia , Adolescente , Adulto , Idoso , Anticestoides/uso terapêutico , Catárticos/administração & dosagem , Criança , Terapia Combinada , Fezes/parasitologia , Humanos , Pessoa de Meia-Idade , Niclosamida/uso terapêutico , Polietilenoglicóis/administração & dosagem , Teníase/diagnósticoRESUMO
The presence of two oncosphere antigens (OAs) of 22.5 and 31.3 kD in whole and excretory/secretory (ES) OA preparations of both Taenia solium and T. saginata or in antigen preparations from T. solium metacestodes or immature tapeworms was assessed. This included an evaluation of whether antibodies to other cestodes cross-reacted to these OAs. The OAs were present in whole oncosphere extract and E/S antigens of T. solium, but were not present in other stages (immature tapeworm or metacestode) or in OAs of T. saginata. The majority (95%) of T. solium tapeworm carriers had antibodies to these OAs, while only 20% of active neurocysticercosis cases were positive. No antibodies to the OAs were found in healthy controls, subjects infected with Hymenolepis nana, patients with hydatid disease, T. saginata tapeworm carriers, hamsters infected with immature T. solium tapeworms, or dogs infected with Echinococcus granulosus. The OAs are stage and species specific to T. solium and antibodies to OAs are usually present in tapeworm carriers.
