Night and crepuscular mosquitoes and risk of vector-borne diseases in areas of piassaba extraction in the middle Negro River basin, state of Amazonas, Brazil.

A study of crepuscular and night-biting mosquitoes was conducted at remote settlements along the Padauiri River, middle Negro River, state of Amazonas, Brazil. Collections were performed with human bait and a CDC-light trap on three consecutive days per month from June 2003-May 2004. In total, 1,203 h of collection were performed, of which 384 were outside and 819 were inside houses. At total of 11,612 specimens were captured, and Anophelinae (6.01%) were much less frequent than Culicinae (93.94%). Anopheles darlingi was the most frequent Anophelinae collected. Among the culicines, 2,666 Culex (Ae.) clastrieri Casal & Garcia, 2,394 Culex. (Mel.) vomerifer Komp, and 1,252 Culex (Mel.) eastor Dyar were the most frequent species collected. The diversity of insects found reveals the receptivity of the area towards a variety of diseases facilitated by the presence of vectors involved in the transmission of Plasmodium, arboviruses and other infectious agents.

[Evaluation of the Optimal-IT and ICT P.f./P.v. rapid dipstick tests for diagnosing malaria within primary healthcare in the municipality of Manaus, Amazonas]. / Avaliação dos testes rápidos Optimal-IT e ICT P.f./P.v. para o diagnóstico da malária, na Atenção Básica de Saúde, no município de Manaus, Amazonas.

Malaria is routinely diagnosed using the thick blood smear test. However, this technique requires the training of microscopists and may be time-consuming. A concordance study was conducted on two dipstick tests (Optimal-IT and ICT P.f./P.v.) and the thick blood smear test, within primary healthcare in Manaus.

[Association of methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency in malaria patients treated with primaquine]. / Associação de metemoglobinemia e deficiência de glicose-6-fosfato desidrogenase em pacientes com malária tratados com primaquina.

This study had the aim of investigating occurrences of methemoglobinemia among individuals with glucose-6-phosphate dehydrogenase deficiency during treatment for malaria infection using primaquine. Patients with a diagnosis of malaria caused by Plasmodium vivax or the V+F mixture (Plasmodium vivax + Plasmodium falciparum) were selected. Group 1 consisted of 74 individuals with a clinical diagnosis of methemoglobinemia and Group 2 consisted of 161 individuals without a clinical diagnosis of methemoglobinemia. The glucose-6-phosphate dehydrogenase deficiency rates (numbers of enzymopenic individuals) in Groups 1 and 2 were 51.3% (38) and 8.7% (14) respectively. These data demonstrated a statistically significant association with methemoglobinemia only among the individuals in Group 1 (p<0.05). Investigation of the relationship between methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency showed that there was a possible association such that enzymopenic individuals may develop methemoglobinemia more frequently.

Successful treatment of Plasmodium falciparum malaria with a six-dose regimen of artemether-lumefantrine versus quinine-doxycycline in the Western Amazon region of Brazil.

This randomized, open-label study compared a three-day, six-dose regimen of artemether-lumefantrine with a five-day, 19-dose regimen of quinine-doxycycline for the treatment of Plasmodium falciparum malaria in the western Amazon region of Brazil. All patients remained hospitalized during their treatment and the study assessments were scheduled daily from the start of treatment (day 0) through day 6. By day 3, the percentage of infected patients was 0% in the artemether-lumefantrine group and 48.8% in the quinine-doxycycline group. Median parasite clearance time was significantly shorter in the artemether-lumefantrine group (two days) compared with the quinine-doxycycline group (three days) (P < 0.0001). Two patients in the quinine-doxycycline group left the study early because of treatment ineffectiveness or adverse event. Adverse events were reported by 91.5% of the study participants, most of which were mild in severity and/or not considered related to study treatment. Artemether-lumefantrine was shown to be an efficacious, safe, and convenient treatment for P. falciparum malaria in a highly drug-resistant region of South America.

Malaria in the State of Amazonas: a typical Brazilian tropical disease influenced by waves of economic development.

In Brazil, more than 99% of malaria cases are reported in the Amazon, and the State of Amazonas accounts for 40% of this total. However, the accumulated experience and challenges in controlling malaria in this region in recent decades have not been reported. Throughout the first economic cycle during the rubber boom (1879 to 1912), malaria was recorded in the entire state, with the highest incidence in the villages near the Madeira River in the Southern part of the State of Amazonas. In the 1970s, during the second economic development cycle, the economy turned to the industrial sector and demanded a large labor force, resulting in a large migratory influx to the capital Manaus. Over time, a gradual increase in malaria transmission was observed in peri-urban areas. In the 1990s, the stimulation of agroforestry, particularly fish farming, led to the formation of permanent Anopheline breeding sites and increased malaria in settlements. The estimation of environmental impacts and the planning of measures to mitigate them, as seen in the construction of the Coari-Manaus gas pipeline, proved effective. Considering the changes occurred since the Amsterdam Conference in 1992, disease control has been based on early diagnosis and treatment, but the development of parasites that are resistant to major antimalarial drugs in Brazilian Amazon has posed a new challenge. Despite the decreased lethality and the gradual decrease in the number of malaria cases, disease elimination, which should be associated with government programs for economic development in the region, continues to be a challenge.

Dengue hemorrhagic fever and acute hepatitis: a case report.

Dengue fever is the world's most important viral hemorrhagic fever disease, the most geographically wide-spread of the arthropod-born viruses, and it causes a wide clinical spectrum of disease. We report a case of dengue hemorrhagic fever complicated by acute hepatitis. The initial picture of classical dengue fever was followed by painful liver enlargement, vomiting, hematemesis, epistaxis and diarrhea. Severe liver injury was detected by laboratory investigation, according to a syndromic surveillance protocol, expressed in a self-limiting pattern and the patient had a complete recovery. The serological tests for hepatitis and yellow fever viruses were negative. MAC-ELISA for dengue was positive.

[Dengue hemorrhagic fever in infants: report of two cases]. / Febre hemorrágica do dengue em lactentes: relato de dois casos.

Two cases of infants assisted at the Tropical Medicine Foundation of Amazonas with febrile exanthematic syndrome and mild hemorrhagic manifestations, defining a picture of dengue hemorrhagic fever. The etiologic diagnose was confirmed by the MAC-ELISA and the Inhibition - ELISA, performed in both infants and respective mothers.

[Culicidae insect fauna from rural zone in Amazonas State with incidence of sylvatic yellow fever]. / Fauna de Culicidae em municípios da zona rural do estado do Amazonas, com incidência de febre amarela.

After the occurrence of 14 sylvatic yellow fever cases in 10 cities in the State of Amazonas during 1996, an investigation into the presence of sylvatic yellow fever vectors was carried out. The material of larvae and adult insects was collected around residences and canopy trees within forests, using a light trap (CDC) and human bait. A total of 424 insects was collected. Thirty seven species were identified, some of which were sylvatic yellow fever vectors: Haemagogus janthinomys, Ha. leucocelaenus, Aedes fulvus.

[Treatment of children with malaria Plasmodium falciparum with derivatives artemisinin]. / Tratamento de crianças com malária pelo Plasmodium falciparum com derivados da artemisinina.

From January 1996 to December 1998, artemisinin derivatives were prescribed to 108 children infected with Plasmodium falciparum. The therapeutic effect was evaluated. Only children with moderate or severe malaria were included. Group I (intravenous artesunate; n = 62): 50.8% with moderate malaria and 49.2% with severe malaria; 53.2% with mild parasitemia, 22.6% with moderate parasitemia and 24.2% with high parasitemia; Group II (intramuscular artemether [Paluter ]; n = 46): 67.4% with moderate malaria and 32.6% with severe malaria; 52.2% with mild parasitemia, 36.2% with moderate parasitemia and 15.2% with high parasitemia; clinical amelioration and clearance of parasitemia showed no statistical difference between the groups. All patients cleared the parasitemia at the seventh day of follow-up (D7). In order to avoid recrudescence, mefloquine or clindamycin was used.

[Typhoid fever: relapse due to antimicrobial resistance. Case report]. / Febre tifóide: recaída por resisténcia antimicrobiana. Relato de caso.

We report for the first time in the Brazilian Amazon a typhoid fever patient with clinical and laboratorial resistance to chloramphenicol, drug of election for this disease in our region. The relapse was observed at the 7th day after the end of treatment and the patient was treated with ciprofloxacin.

[Exanthematous diseases and the first epidemic of dengue to occur in Manaus, Amazonas State, Brazil, during 1998-1999]. / Doenças exantemáticas e primeira epidemia de dengue ocorrida em Manaus, Amazonas, no período de 1998-1999.

In 1998, the FMT/IMT-AM foundation implemented the surveillance system to diagnose acute undifferentiated febrile syndromes, with the objective of active and passive surveillance in Brazilian western Amazonian rainforest to identify and diagnose the etiologic agents of acute fever. The diagnoses were performed using serological tests to detect IgM antibodies by ELISA (Enzyme-linked-immunosorbent assay) CDC/OPAS or using commercial kits. A total of 8,557 serum samples obtained from patients with clinical suspicion of dengue virus were analyzed. ELISA positive reaction to dengue virus was presented by 40% of the serum samples and 26% of the serum samples had positive ELISA reactions to other exanthematous viral diseases, such as rubella, measles, parvovirus, Oropouche virus and Mayaro virus.

[Registration of the occurrence of Aedes albopictus in an urban zone in Manaus, Amazonas, Brazil]. / Registro da ocorrência de Aedes albopictus em área urbana do município de Manaus, Amazonas.

Information is available regarding the presence of Aedes albopictus in several municipalities of the State of Amazonas. Specimens of this mosquito species have now, for the first time, been collected from an urban area of the municipality of Manaus, Amazonas, Brazil.

Non-planed urbanization as a contributing factor for malaria incidence in Manaus-Amazonas, Brazil.

OBJECTIVES: This paper presents a study on the dynamics of malaria in Manaus and its relationship with the urban expansion and environmental factors related to it. The purpose of this paper is: to analyse how the form of occupying the emptied space in the city, together with the urbanization and factors related to the environment, have contributed for the establishment, increase and/or sustainability of malaria in the urban area of the city of Manaus, Amazonas, Brazil. METHODS: A retrospective study was carried out on malaria epidemiology from 1986 to 1997; data on the evolution and urban expansion of the city of Manaus were surveyed. Data were descriptively analysed making a relationship between the environmental aspects of urbanization and the way the city of Manaus was occupied and how this has contributed to malaria epidemiology in the city. RESULTS: The findings point out to the importance of the environment on malaria incidence, and to the influence of the anthropic interventions on the modification of the ecosystem, making the urban environment ideal for the proliferation of Anopheles sp mosquitoes, vectors of this disease. CONCLUSION: These elements in association continue to favour the maintenance of the incidence of malaria in the urban area of Manaus.

Malaria in the State of Amazonas: a typical Brazilian tropical disease influenced by waves of economic development

In Brazil, more than 99% of malaria cases are reported in the Amazon, and the State of Amazonas accounts for 40% of this total. However, the accumulated experience and challenges in controlling malaria in this region in recent decades have not been reported. Throughout the first economic cycle during the rubber boom (1879 to 1912), malaria was recorded in the entire state, with the highest incidence in the villages near the Madeira River in the Southern part of the State of Amazonas. In the 1970s, during the second economic development cycle, the economy turned to the industrial sector and demanded a large labor force, resulting in a large migratory influx to the capital Manaus. Over time, a gradual increase in malaria transmission was observed in peri-urban areas. In the 1990s, the stimulation of agroforestry, particularly fish farming, led to the formation of permanent Anopheline breeding sites and increased malaria in settlements. The estimation of environmental impacts and the planning of measures to mitigate them, as seen in the construction of the Coari-Manaus gas pipeline, proved effective. Considering the changes occurred since the Amsterdam Conference in 1992, disease control has been based on early diagnosis and treatment, but the development of parasites that are resistant to major antimalarial drugs in Brazilian Amazon has posed a new challenge. Despite the decreased lethality and the gradual decrease in the number of malaria cases, disease elimination, which should be associated with government programs for economic development in the region, continues to be a challenge.

Glucose-6-phosphate dehydrogenase deficiency in an endemic area for malaria in Manaus: a cross-sectional survey in the Brazilian Amazon.

BACKGROUND: There is a paucity of information regarding glucose-6-phosphate dehydrogenase (G6PD) deficiency in endemic areas for malaria in Latin America. METHODOLOGY/PRINCIPAL FINDINGS: This study determined the prevalence of the G6PD deficiency in 200 male non-consanguineous individuals residing in the Ismail Aziz Community, on the outskirts of Manaus (Brazilian Amazon). Six individuals (3%) were deficient using the qualitative Brewer's test. Gel electrophoresis showed that five of these patients were G6PD A(-). The deficiency was not associated with the ethnic origin (P = 0.571). In a multivariate logistic regression analysis, G6PD deficiency protected against three or more episodes of malaria (P = 0.049), independently of the age, and was associated with a history of jaundice (P = 0.020) and need of blood transfusion (P = 0.045) during previous treatment for malarial infection, independently of the age and the previous malarial exposure. CONCLUSIONS/SIGNIFICANCE: The frequency of G6PD deficiency was similar to other studies performed in Brazil and the finding of a predominant G6PD A(-) variant will help the clinical management of patients with drug-induced haemolysis. The history of jaundice and blood transfusion during previous malarial infection may trigger the screening of patients for G6PD deficiency. The apparent protection against multiple malarial infections in an area primarily endemic for Plasmodium vivax needs further investigation.

Comparative study of serologic tests for the diagnosis of asymptomatic visceral leishmaniasis in an endemic area.

Serologic tests have been widely used for the diagnosis of asymptomatic visceral leishmaniasis. This study evaluated five serologic tests used for the diagnosis of asymptomatic infection: enzyme-linked immunosorbent assay (ELISA) using promastigote antigen (ELISAp), ELISA using recombinant K39 (ELISA rK39), and K26 (ELISA rK26) antigens, an indirect immunofluorescence test using Leishmania (Leishmania) amazonensis promastigote antigen (IIFT), and an immunochromatographic test using rK39 antigen (TRALd). As a reference regarding the performance of the tests, patients with classic visceral leishmaniasis originating from Minas Gerais, Brazil (N = 36), were defined as the positive group and samples of healthy individuals from nonendemic areas (Argentina) (N = 127) were used as negative controls. Patients with other diseases such as cutaneous leishmaniasis (N = 53) and malaria (N = 56) were also studied to evaluate the chance of cross-reactivity in these tests. Finally, subjects from an area endemic for visceral leishmaniasis in Brazil (Porteirinha, northern Minas Gerais) (N = 1241) were screened for asymptomatic infection with Leishmania and Chagas disease. The sensitivity of the serologic tests was 50% (18/36), 66.7% (24/36), 69.4% (25/36), 83.3% (30/36), and 88.9% (32/36) for ELISAp, ELISA rK26, ELISA rK39, IIFT, and TRALd, respectively. Specificity, calculated using the truly negative group, was 96% (122/127) for TRALd, 97.6% (124/127) for ELISAp and IIFT, and 100% (127/127) for ELISA rK39 and rK26. Positivity in at least one test employing recombinant antigen was observed in 24 (45%) patients with cutaneous leishmaniasis and 47 (82.4%) with malaria. In the visceral leishmaniasis-endemic area, the positivity of the serologic tests ranged from 3.9% to 37.5%. The enzyme-linked immunosorbent assay (ELISA) tests using recombinant antigens were more frequently positive in subjects with a history of exposure to human or canine visceral leishmaniasis (ELISArK39: 14.6% [149/1017] versus 37.5% [84/224]; ELISA rK26: 12.7% [129/1017] versus 21.4% [48/224], P < 0.001 for both). Kappa agreement was low, with a maximum value of 0.449 between ELISAp and IIFT. In addition, among the 112 IIFT-positive subjects, 75 (67%) also presented positive serology for Chagas disease. In conclusion, IIFT and TRALd presented the best performance to diagnose classic cases of visceral leishmaniasis in an endemic area. Cross-reactivity of the tests with Chagas disease, cutaneous leishmaniasis, and malaria should be taken into account. However, the differences in the positivity of the tests used, together with the low agreement between results, do not permit to select the best test for the diagnosis of asymptomatic Leishmania infection.

[Molecular diagnosing of malaria in a tertiary care center in the Brazilian Amazon region]. / Diagnóstico molecular da malária em uma unidade de atenção terciária na Amazônia Brasileira.

The routine test for diagnosing malaria is still the thick blood smear, despite its known decreased sensitivity and specificity in situations of low parasite density and mixed infections. The polymerase chain reaction is increasingly being used for molecular detection and identification of Plasmodium species, due to its higher sensitivity and specificity. Nested PCR was performed on whole-blood samples from 344 patients with acute febrile syndrome who came to a tertiary healthcare center in Manaus (State of Amazonas) for diagnostic confirmation of malaria. No malaria cases caused by Plasmodium malariae were detected through the blood smear or PCR. Co-positivity of 96.7%, co-negativity of 62.2% and kappa coefficient of 0.44 were observed between PCR and thick blood smear for Plasmodium falciparum. For Plasmodium vivax, co-positivity of 100%, co-negativity of 78.1% and kappa coefficient of 0.56 were observed. For mixed infection, co-positivity of 100%, co-negativity of 84.9% and kappa coefficient of 0.26 were observed. Polymerase chain reaction detected a high number of mixed infections in the samples analyzed, but its routine use for diagnosing malaria still deserves further discussion.

In vitro inhibition of Plasmodium falciparum by substances isolated from Amazonian antimalarial plants.

In the present study, a quassinoid, neosergeolide, isolated from the roots and stems of Picrolemma sprucei (Simaroubaceae), the indole alkaloids ellipticine and aspidocarpine, isolated from the bark of Aspidosperma vargasii and A. desmanthum (Apocynaceae), respectively, and 4-nerolidylcatechol, isolated from the roots of Pothomorphe peltata (Piperaceae), all presented significant in vitro inhibition (more active than quinine and chloroquine) of the multi-drug resistant K1 strain of Plasmodium falciparum. Neosergeolide presented activity in the nanomolar range. This is the first report on the antimalarial activity of these known, natural compounds. This is also the first report on the isolation of aspidocarpine from A. desmanthum. These compounds are good candidates for pre-clinical tests as novel lead structures with the aim of finding new antimalarial prototypes and lend support to the traditional use of the plants from which these compounds are derived.