RESUMEN
The study of genetic diversity in malaria populations is expected to provide new insights for the deployment of control measures. Plasmodium falciparum diversity in Africa and Asia is thought to reflect endemicity. In comprehensive epidemiological surveys reported here the genetic and antigenic structure of P. falciparum in the Venezuelan Amazon were studied over a 2-year period. DNA polymorphisms in glutamate-rich protein (GLURP), merozoite-surface protein 1 (MSP1) and MSP2 genes, in a multicopy element (PfRRM), all showed low diversity, 1 predominant genotype, and virtually no multi-clonal infections. Moreover, linkage disequilibrium was seen between GLURP, MSP1 and MSP2. Specific antibody responses against MSP1 and MSP2 recombinant antigens reflected the low genetic diversity observed in the parasite population. This is unexpected in a mesoendemic area, and suggests that the low diversity here may not only relate to endemicity but to other influences such as a bottleneck effect. Linkage disequilibrium and a predominant genotype may imply that P. falciparum frequently propagates with an epidemic or clonal population structure in the Venezuelan Amazon.
Asunto(s)
Antígenos de Protozoos/genética , Antígenos de Protozoos/inmunología , Variación Genética/genética , Variación Genética/inmunología , Malaria Falciparum/parasitología , Plasmodium falciparum/genética , Plasmodium falciparum/inmunología , Animales , Electroforesis en Gel de Agar , Frecuencia de los Genes , Genotipo , Humanos , Desequilibrio de Ligamiento , Malaria Falciparum/epidemiología , Malaria Falciparum/inmunología , Malaria Falciparum/prevención & control , Proteína 1 de Superficie de Merozoito/genética , Filogenia , Polimorfismo Genético/genética , Prevalencia , Proteínas Protozoarias/genética , Especificidad de la Especie , Venezuela/epidemiologíaRESUMEN
Fifteen extracts from nine selected Argentine medicinal plants were tested for their antiplasmodial activity in vitro by assessing their ability to inhibit the uptake of [3H]-hypoxanthine into the Plasmodium falciparum K1 pyrimethamine/chloroquine resistant strain. The methanol extract of Satureja parvifolia showed good antiplasmodial activity (IC(50) 3 microg/ml). Inhibition of the growth of P. falciparum was also observed with aqueous extracts of Buddleja globosa and S. parvifolia.
Asunto(s)
Antimaláricos/farmacología , Plantas Medicinales , Plasmodium falciparum/efectos de los fármacos , Animales , Argentina , Resistencia a Medicamentos , Concentración 50 Inhibidora , Extractos Vegetales/farmacologíaRESUMEN
We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3%, 6.2% and 20.4% were detected by human blood smears in Colônia Agua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4% were identified as Anopheles albitarsis s.l., 16.7% An. braziliensis, 9.5% An. nuneztovari and 5.8% An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8% (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area.
Asunto(s)
Anopheles/parasitología , Insectos Vectores/parasitología , Malaria/transmisión , Plasmodium/aislamiento & purificación , Animales , Brasil , Ensayo de Inmunoadsorción Enzimática , Humanos , Estaciones del AñoRESUMEN
We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3 percent, 6.2 percent and 20.4 percent were detected by human blood smears in Colônia ægua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4 percent were identified as Anopheles albitarsis s.l., 16.7 percent An. braziliensis, 9.5 percent An. nuneztovari and 5.8 percent An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8 percent (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area
Asunto(s)
Humanos , Animales , Anopheles/parasitología , Insectos Vectores/parasitología , Malaria/transmisión , Plasmodium/aislamiento & purificación , Brasil , Ensayo de Inmunoadsorción Enzimática , Estaciones del AñoRESUMEN
Bioactivity-directed fractionation of the CHCl3-MeOH extract of the leaves of Celaenodendron mexicanum by means of the brine shrimp lethality test and chromatographic techniques led to the isolation of three carboxylic acid triterpenes, the new tirucalla-type triterpene, 3 alpha-hydroxytirucalla-7,24Z-dien-26-oic acid, 3-oxotirucalla-7,24Z-dien-26-oic acid, and epi-oleanolic acid, and three biflavonoids amentoflavone, podocarpusflavone A, and podocarpusflavone B. Four non-active compounds friedelin, maytensifolin B, 3 beta-hydroxyfriedelan-16-one, and celaenodendrolide were also obtained. epi-Oleanolic acid was the most active against brine shrimps with LC50 value of 23.3 microM. In addition, all isolates were tested for in vitro antiprotozoal and cytotoxic activities. 3-Oxotirucalla-7,24Z-dien-26-oic acid and epi-oleanolic acid showed the highest activity against Leishmania donovani promastigotes with IC50 values of 13.7 and 18.8 microM, respectively. Only 3-oxotirucalla-7,24Z-dien-26-oic acid showed activity against Trypanosoma brucei brucei bloodstream forms with IC50 value of 16.8 microM.
Asunto(s)
Antiprotozoarios/aislamiento & purificación , Euphorbiaceae/química , Flavonoides/aislamiento & purificación , Triterpenos/aislamiento & purificación , Animales , Antiprotozoarios/química , Antiprotozoarios/farmacología , Flavonoides/química , Flavonoides/farmacología , Concentración 50 Inhibidora , Leishmania donovani/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Extractos Vegetales/química , Hojas de la Planta/química , Plasmodium falciparum/efectos de los fármacos , Triterpenos/química , Triterpenos/farmacología , Trypanosoma brucei brucei/efectos de los fármacosRESUMEN
Parasite resistance to antimalarial drugs, particularly chloroquine, is the most disturbing problem of malaria chemotherapy. There is evidence that the codon 86Tyr polymorphism of the Pfmdr1 gene is associated with chloroquine resistance in West African Plasmodium falciparum. The association of this and four other coding alterations of the Pfmdr1 gene with chloroquine resistance has not been extensively investigated in South American isolates. In this study, we examined 51 Brazilian P. falciparum isolates for the presence or absence of Asn86Tyr, Asn1042Asp, and Asp1246Tyr polymorphisms. While these isolates were all sensitive in vitro to mefloquine, amodiaquine, and quinine, only 2 (4%) were chloroquine-sensitive. The findings reported here provide the first observations of this kind on a large number of field parasite samples from South America. We show that in vitro chloroquine-resistant and -sensitive strains carry the Asn1042Asp and Asp1246Tyr polymorphisms and provide support for earlier suggestions that Asn86Tyr may be rare or absent in South American P. falciparum.
Asunto(s)
Antimaláricos/farmacología , Cloroquina/farmacología , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/genética , Polimorfismo de Longitud del Fragmento de Restricción , Amodiaquina/farmacología , Animales , Resistencia a Medicamentos/genética , Humanos , Mefloquina/farmacología , Reacción en Cadena de la Polimerasa , Quinina/farmacologíaRESUMEN
We report an adaptation of a technique for the blood sample collection (GFM) as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing the cost by more than half. The material is also suitable for genetic analysis in either fresh or stored specimens prepared by this method.
Asunto(s)
Recolección de Muestras de Sangre/métodos , ADN Protozoario/análisis , Malaria/diagnóstico , Reacción en Cadena de la Polimerasa , Animales , Recolección de Muestras de Sangre/economía , Ensayo de Inmunoadsorción Enzimática , Plasmodium/genéticaRESUMEN
Medicinal plants are an important health resource in many regions of the Americas and are of particular importance to many Indian communities. Based on a recent ethnobotanical study in Mexico, we investigated the activity of 29 plant extracts against Entamoeba histolytica, three bacteria (Bacillus subtilis, Escherichia coli, and Micrococcus luteus) and two fungi (Cladosporium cucumerinum and Penicillium oxalicum). After separation of these extracts between CH2Cl2 and H2O the resulting phases were also evaluated.
Asunto(s)
Amebicidas/farmacología , Antibacterianos/farmacología , Antifúngicos/farmacología , Indígenas Centroamericanos , Extractos Vegetales/farmacología , Plantas Medicinales/microbiología , Plantas Medicinales/parasitología , Humanos , Medicina Tradicional , México , Pruebas de Sensibilidad MicrobianaRESUMEN
Genotypic differences between invasive and non-invasive E. histolytica could explain the 1:10 ratio of symptomatic/asymptomatic infection worldwide. Currently, zymodeme analysis is used to differentiate invasive from non-invasive E. histolytica strains but the technique is cumbersome and expensive. In accordance with the WHO research priorities for amebiasis we report here the further use of an invasive-specific monoclonal antibody against E. histolytica in immunofluorescence, to identify isolates cultured from stool samples of patients from three geographically distant endemic regions: Bangladesh, Colombia and Mexico. We tested 107 E. histolytica isolates and the correlation between zymodeme characterization and the immunofluorescence assay was 100%.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos Antiprotozoarios/inmunología , Disentería Amebiana/parasitología , Entamoeba histolytica/inmunología , Técnica del Anticuerpo Fluorescente , Animales , Bangladesh/epidemiología , Colombia/epidemiología , Disentería Amebiana/epidemiología , Entamoeba histolytica/enzimología , Entamoeba histolytica/genética , Entamoeba histolytica/aislamiento & purificación , Entamoeba histolytica/patogenicidad , Heces/parasitología , Isoenzimas/análisis , México/epidemiología , Proteínas Protozoarias/análisis , VirulenciaRESUMEN
Fecal samples were obtained from 722 of 820 children attending 7 nursery schools and 1 primary school in the city of Santiago, Chile. Microscopy of formol-ether concentrates showed that 33% of the children were infected with Giardia lamblia. Prevalences among primary school students (5-10 years of age) of G. lamblia (38%), Endolimax nana (43%), and Entamoeba coli (25%) were overall higher than among nursery school students (3 months-5 years of age; prevalences 29%, 21%, and 16%, respectively). There was no apparent association between socio-economic intake and levels of G. lamblia infection: the private nursery school had the highest recorded level of infection (40%). One hundred sixty-two triplicate stool specimens were used to compare microscopy with an enzyme-linked immunosorbent assay (ELISA) for the detection of Giardia fecal antigens. The ELISA was highly sensitive and specific either visually (95% and 97%, respectively) or by optical density determination (99% and 96%, respectively). Incorporation of non-immune rabbit immunoglobulin-coated control wells did not enhance sensitivity and specificity. The antigen detection ELISA is an extremely effective tool for the epidemiological investigation of giardiasis.
Asunto(s)
Antígenos de Protozoos/análisis , Ensayo de Inmunoadsorción Enzimática , Heces/parasitología , Giardia/inmunología , Giardiasis/diagnóstico , Animales , Niño , Preescolar , Chile/epidemiología , Femenino , Giardiasis/epidemiología , Humanos , Lactante , Masculino , Valor Predictivo de las Pruebas , Prevalencia , Estaciones del AñoRESUMEN
Extracts prepared from Simarouba amara fruits collected in Panama have been found to be active against Plasmodium falciparum in vitro and against Plasmodium berghei in mice. Four active quassinoids have been identified as ailanthinone, 2'-acetylglaucarubinone, glaucarubinone and holacanthone.