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The aim of this study was to determine how different types of P. vivax affect clinical symptoms and parasitaemia clearance. Blood was collected from individuals from Pará State, Brazil. The patients were treated as chloroquine plus primaquine. P. vivax were typed daily till D7 and again on D30. Now we can confirm a previously reported correlation between P. vivax genotype and response to chloroquine. Clinical symptoms do not allow for objective identification of different P. vivax types in the Brazilian Amazon, since the VK247 and P. vivax-like have only been detected in mixed infections. Key Words: Plasmodium vivax variants, symptoms, chloroquine and primaquine treatment, clearence of parasitaemia. Plasmodium vivax has been the most common cause of human malaria in the Brazilian Amazon region during the last seven years. Its variants (VK210, are found in mixed infections; VK210 has also been found as a single infection [9]. Reduction in susceptibility to chloroquine has been reported from Papua New Guinea, India, Asia and South America [1,13,19], though no relationship between P. vivax genotypes and parasite clearance following treatment with chloroquine has been found. Kain et al. (1993) suggested that response to chloroquine varies depending on the type of P. vivax, since the VK210 genotype and mixed infection with VK247 took longer to clear, while VK247 tended to have a shorter duration in Thailand. A study conducted in Brazil showed no significant difference in the time of parasite clearance after treatment with chloroquine and primaquine, alone or combined [9]. Variants of P. vivax can produce different clinical signs and responses to treatment [5], as there is a correlation between P. vivax genotypes and the intensity of symptoms and vector preference, which can affect drug resistance and consequent failure of control measures [4]. We examined how different types of P. vivax affect clinical symptoms and parasitaemia clearance.Blood was collected from 30 individuals from Belém city (Pará State) who had signed the informed consent form. The blood samples were obtained before therapy was initiated (D0), and continued daily till day 5 (D5). Vacutainer tubes containing EDTA (Becton Dickinson, UK) were used to collected 5 mL of whole blood/ individual that was subsequently applied to glass-fibermembrane discs (Titertek, ICN Biomedicals Limited, UK) following the protocol described by Warhurst et al. [21]. The patients were treated as follows: 25 mg chloroquine/kg body weight during 3 days (10 mg/kg on day 1 and 7.5 mg/kg on days 2 and 3), plus 0.25 mg primaquine /kg for 14 days, starting on the fourth day. Plasmodium vivax types were identified by 176 BJID 2003; 7 (June) GFM/PCR/ELISA [9] for all samples. The patients were evaluated daily by a physician till D7, and again on D30.The typing of P. vivax genotype in D0 detected 16 samples with a single infection, all by VK210 (53%) and 14 samples with mixed infections (47%): four VK210 plus VK247 (13%), two VK210 plus P. vivax-like (7%), five VK247 plus P. v...

OBJECTIVE: To report an outbreak of human toxoplasmosis that occurred in the District of Monte Dourado, Municipality of Almeirim, Pará State, Brazil. MATERIALS AND METHODS: After the positive diagnosis of five patients with symptoms suggestive of toxoplasmosis, clinical research and epidemiology were executed in the locality. A total of 186 individuals were evaluated, including symptomatic patients, their relatives and/or close contacts. All subjects underwent epidemiological inquiry, clinical assessment and serology by enzyme-linked immunosorbent assay (ELISA) for detection of anti-Toxoplasma gondii IgG and IgM. RESULTS: A total of 40 individuals presented a serological profile of acute toxoplasmosis. Epidemiological analysis indicated that the cases could be related to infection with oocysts eliminated by cats, whose population density was very high in the surveyed locality. The most likely hypothesis of transmission would be through direct contact with oocysts of the parasite, either by the ingestion of contaminated food or by the inhalation of these forms in the soil. The possibility of water transmission through the local supply system was discarded because the system is inaccessible to cats. Infected individuals were treated at the local health care units. Moreover, local health authorities were instructed to implement measures to control stray cats in order to prevent new cases or outbreaks. CONCLUSION: The outbreak that occurred between February and March 2004 in Monte Dourado was caused by T. gondii. The hypothesis of contamination via oocysts of the parasite is supported by several factors, such as a high population density of cats in the surveyed District, frequent gardening habits and a lack of reports of ingestion of raw or undercooked meat.

Ethnomedicinal informations point to some Aspidosperma species (Apocynaceae) as antimalarial plants in Brazil and have motivated the evaluation of six species which were collected in the state of Minas Gerais: A. cylindrocarpon Müll. Arg., A. parvifolium A. DC., A. olivaceum Müll. Arg., A. ramiflorum Müll. Arg., A. spruceanum Benth. ex Müll. Arg. and A. tomentosum Mart.. A total of 23 extracts of different plant parts in different solvents were assayed in vitro against chloroquine-resistant (W2) and chloroquine-sensitive (3D7) strains of Plasmodium falciparum. All the extracts were shown to be active with IC 50 values in the range of 5.0 ± 0 2.8 µg/mL to 65.0 ± 4.2 µg/mL. TLC profile of the extracts revealed the presence of alkaloids in the six species assayed. These results seem to confirm the popular use of Aspidosperma species to treat human malaria in Brazil and seem point to alkaloids as the putative active compounds of the assayed species.

Histidine-rich proteins 2 and 3 gene (pfhrp2 and pfhrp3) deletions affect the efficacy of rapid diagnostic tests (RDTs) based on the histidine-rich protein 2 (HRP2), compromising the correct identification of the Plasmodium falciparum species. Therefore, molecular surveillance is necessary for the investigation of the actual prevalence of this phenomenon and the extent of the disappearance of these genes in these areas and other South American countries, thus guiding national malaria control programs on the appropriate use of RDTs. This study aimed to evaluate the pfhrp2 and pfhrp3 gene deletion in P. falciparum in endemic areas of the Brazilian Amazon. Aliquots of DNA from the biorepository of the Laboratory of Basic Research in Malaria, Evandro Chagas Institute, with a positive diagnosis for P. falciparum infection as determined by microscopy and molecular assays, were included. Monoinfection was confirmed by nested-polymerase chain reaction assay, and DNA quality was assessed by amplification of the merozoite surface protein-2 gene (msp2). The pfhrp2 and pfhrp3 genes were amplified using primers for the region between exons 1 and 2 and for all extension of exon 2. Aliquots of DNA from 192 P. falciparum isolates were included in the study, with 68.7% (132/192) from the municipality of Cruzeiro do Sul (Acre) and 31.3% (60/192) from Manaus (Amazonas). Of this total, 82.8% (159/192) of the samples were considered of good quality. In the state of Acre, 71.7% (71/99) showed pfhrp2 gene deletion and 94.9% (94/99) showed pfhrp3 gene deletion, while in the state of Amazonas, 100.0% (60/60) of the samples showed pfhrp2 gene deletion and 98.3% (59/60) showed pfhrp3 gene deletion. Moreover, 79.8% (127/159) of isolates displayed gene deletion. Our findings confirm the presence of a parasite population with high frequencies of pfhrp2 and pfhrp3 gene deletions in the Brazilian Amazon region. This suggests reconsidering the use of HRP2-based RDTs in the Acre and Amazonas states and calls attention to the importance of molecular surveillance and mapping of pfhrp2/pfhrp3 deletions in this area and in other locations in the Amazon region to guarantee appropriate patient care, control and ultimately contribute to achieving P. falciparum malaria elimination.