Aedes albopictus may not be vector of dengue virus in human epidemics in Brazil

Over 60,500 dengue cases were reported in the state of Espírito Santo (ES), Brazil, between 1995 and 1998. The study's purpose was to identify whether Aedes albopictus was transmitting the dengue virus during an epidemic in the locality of Vila Bethânia (Viana County),Vitória, ES. From April 3 to 9, 1998, blood and serum samples were collected daily for virus isolation and serological testing. Four autochthonous cases were confirmed through DEN 1 virus isolation and two autochthonous cases through MAC ELISA testing. Of 37 Ae. aegypti and 200 Ae. albopictus adult mosquitoes collected and inoculated, DEN1 virus was isolated only from a pool of two Ae. aegypti female mosquitoes. The study results suggest that Ae. albopictus still cannot be considered an inter-human vector in dengue epidemics in Brazil.

Aspectos epidemiológicos das infecções por rota vírus no Distrito Federal, Brasil

Rotavírus foram pesquisados em 607amostrasfecais de crianças de até 6 anos de idade com quadros de diarréia aguda, no período de maio de 1986 a abril de 1990. Foi utilizada a técnica de eletroforese em gel depoliacrilamida (PAGE), sendo os rotavírus detectados em 123 amostras (20,27%) das quais 107(87,00%) apresentaram perfil eletroforético longo, compatível com o subgrupo II. Os rotavírus não foram encontrados no grupo controle constituído de crianças sadias, sendo porém detectados em 7,80% das crianças internadas por outras causas que não diarréia aguda. A maioria das crianças positivas para rotavírus encontrava-se na faixa etária de 6a24 meses (73,98%). A média depositividade nos meses chuvosos (outubro a abril) foi igual a 9,60% e no período seco, 34,48% com picos que variaram entre 53,17 e 73,27% nos meses de junho e julho, os mais frios do ano.

Associação entre incidência de dengue, pluviosidade e densidade larvária de Aedes aegypti, no Estado de Goiás

INTRODUÇÃO: A densidade larvária de Aedes aegypti flutua de acordo com as variações climáticas sazonais, elevando-se nas estações de maior pluviosidade, em função do número de potenciais criadouros disponíveis, o que predispõe ao aumento da incidência de dengue. Este estudo teve o objetivo de mostrar a associação entre os casos de dengue, a pluviosidade e o índice de infestação predial. MÉTODOS: Os municípios foram estratificados de acordo com transmissão e risco de dengue, e infestados ou não pelo mosquito. Utilizou-se o índice de infestação predial larvário (IIP) como indicador de risco de transmissão. RESULTADOS: Houve correlação positiva entre o IIP, o número de casos de dengue e a pluviosidade. A transmissão da doença foi maior nos quatro primeiros meses de cada ano estudado, período de elevada pluviosidade, diminuindo, nos meses de junho a setembro, época de poucas chuvas. Os casos de dengue mostraram-se contínuos e crescentes nos meses de janeiro a março de cada ano, declinando nos meses de abril e maio, quando ocorreu a interrupção na maioria dos municípios. A região metropolitana de Goiânia foi responsável por mais de 80% dos casos de dengue em Goiás e a transmissão foi contínua em todos os meses, embora baixa no período de maio a dezembro, mas com aumento nos três últimos meses, os quais, normalmente, apresentam índices baixos de transmissão. CONCLUSÕES: A correlação positiva entre o IIP e a pluviosidade, e o IIP e a incidência de casos, apontaram para uma associação significativa crescente na transmissão e no número de casos de dengue.

Anormalidades cardiovasculares e metabólicas em pacientes com a síndrome de Berardinelli-Seip

FUNDAMENTO: A síndrome de Berardinelli-Seip (SBS) ou lipodistrofia generalizada congênita acomete, frequentemente, o aparelho cardiovascular e também promove anormalidades metabólicas que envolvem os metabolismos glicídico e lipídico. OBJETIVO: Avaliar a prevalência das anormalidades cardiovasculares e metabólicas em portadores da SBS. MÉTODOS: Vinte e dois pacientes do Estado do Rio Grande do Norte (Brasil), com diagnóstico da SBS, foram submetidos a avaliação clínica, eletrocardiograma de repouso, ecodopplercardiograma, radiografia de tórax, eletrocardiografia dinâmica de 24 horas, teste ergométrico e análise laboratorial. RESULTADOS: Os pacientes eram, predominantemente, adultos jovens, sendo a maioria do sexo feminino. A totalidade da amostra apresentou resistência à insulina, acanthosis nigricans e HDL-colesterol diminuído. A presença de esplenomegalia, hepatomegalia, diabetes mellitus tipo II e triglicérides elevados era constante. A síndrome metabólica foi caracterizada na maioria dos pacientes, com predominância no sexo feminino e com um alto grau de consanguinidade paterna. A hipertensão arterial sistêmica e a pré-hipertensão foram encontradas em mais da metade dos pacientes (77,3%). O ecodopplercardiograma mostrou a presença de hipertrofia concêntrica do ventrículo esquerdo (50%), hipertrofia excêntrica do ventrículo esquerdo (4,5%) e geometria normal do ventrículo esquerdo (45,5%). Elevada taxa de arritmia foi evidenciada no holter, tais como extrassístoles ventriculares, extrassístoles supraventriculares e taquicardia supraventricular sustentada. A incompetência cronotrópica (54,5%) foi observada no teste ergométrico. CONCLUSÃO: Anormalidades cardiovasculares e metabólicas foram observadas em elevada prevalência em indivíduos jovens e assintomáticos com SBS. Esses achados apontam para a necessidade de acompanhamento cardiológico sistemático e de medidas preventivas nesse grupo de risco.

Development of sporogonic cycle of Plasmodium vivax in experimentally infected Anopheles albimanus mosquitoes

The sporogonic cycle of Plasmodium vivax was established and maintained under laboratory conditions in two different strains of Anopheles albimanus mosquitoes using as a parasite source blood from human patients or from Aotus monkeys infected with the VCC-2 P.vivax colombian isolate. Both the Tecojate strain isolate from Guatemala and the Cartagena strain from the colombian Pacific coast were susceptible to infections with P.vivax. A higher percentage of Cartagena mosquitoes was infected per trial, however the Tecojate strain developed higher sporozoite loads. Intravenous inoculation of Aotus monkeys with sporozoites obtained from both anopheline strains resulted in successful blood infections. Animals infected with sporozoites from the Tecojate strain presented a patent period of 21-32 days whereas parasitemia appeared between days 19-53 in monkeys infected with sporozites from Cartagena strain.

Detection of calicivirus from fecal samples from children with acute gastroenteritis in the West Central region of Brazil

The objective of this study was to describe the circulation of caliciviruses in the West Central region of Brazil and its correlation with children's gender and age, as well as with the year and months of the sample collection. Reverse transcriptase-polymerase chain reaction was performed to detect the human calicivirus genome in 1006 fecal samples that were collected in Goiânia (n = 696) and Brasília (n = 310). Viral RNA was detected in 8.6% of the samples. No significant difference in viral prevalence was found regarding gender, age or year of the sample. However, it was observed that in Goiânia, there is a higher incidence of caliciviruses from September to March. The analysis employing three primer pairs demonstrated that the Ni/E3 or JV12/13 primer pairs, which detect norovirus (NoV), detected 41 positive samples while the 289/290 primer pair, which detects NoV or sapovirus, detected the remaining 46 samples. Calicivirus circulates in the West Central region of Brazil and for better detection of this virus it is important to use more than one primer pair. Also, we conclude that the seasonality presented by this virus is related to higher humidity in the period.

An ecological field study of the water-rat Nectomys squamipes as a wild reservoir indicator of Schistosoma mansoni transmission in an endemic area

Small mammals are found naturally infected by Schistosoma mansoni, becoming a confounding factor for control programs of schistosomiasis in endemic areas. The aims of this study were: to investigate the infection rates by S. mansoni on the water-rat Nectomys squamipes during four years in endemic areas of Sumidouro, state of Rio de Janeiro, using mark-recapture technique; to compare two diagnostic methods for schistosomiasis; and to evaluate the effects of the chemotherapy in the human infected population on the rodent infection rates. The rodent infection rates of S. mansoni increased when rodent population sizes were lower. Coprology and serology results presented the same trends along time and were correlated. Serology could detect recent infection, including the false negatives in the coprology. The chemotherapy in the humans could not interrupt the rodent infection. Rodents can increase the schistosomiaisis transmission where it already exists, they probably maintain the transmission cycle in the nature and can be considered as biological indicators of the transmission sites of this parasite since they are highly susceptible to infection. The water-rats may present different levels of importance in the transmission dynamics of S. mansoni infection cycle for each area, and can be considered important wild-reservoirs of this human disease.

Astrovirus infection in children living in the Central West region of Brazil

This study presents data regarding the circulation of astrovirus in Goiânia-GO and Brasília-DF. These viruses were detected in fecal samples from hospitalized children up to five years old with and without acute gastroenteritis. A total of 1244 fecal samples were collected in two periods, 1994 to 1996 (Brasília) and 1998 to 2002 (Goiânia and Brasília), and were analyzed for viral RNA using the reverse transcription-polymerase chain reaction (RT-PCR). Positivity rates of 4.3 and 0.5% for astrovirus were observed in children with acute gastroenteritis and those without gastroenteritis, respectively. Among children with gastroenteritis no statistically significant difference was seen with regards to viral positivity rates in relation to gender and age. However, a higher incidence rate was observed for children from Brasília aged 36 months or more. Overall, astroviruses occurred predominantly from September to March in the two cities, suggesting a seasonal pattern for these viruses which coincides with the highest relative air humidity period. The results of this study highlight the importance of astrovirus as an etiologic agent of acute gastroenteritis in children of the Central West region of Brazil.

Plasmodium vivax thrombospondin related adhesion protein: immunogenicity and protective efficacy in rodents and Aotus monkeys

The thrombospondin related adhesion protein (TRAP) is a malaria pre-erythrocytic antigen currently pursued as malaria vaccine candidate to Plasmodium falciparum. In this study, a long synthetic peptide (LSP) representing a P. vivax TRAP fragment involved in hepatocyte invasion was formulated in both Freund and Montanide ISA 720 adjutants and administered by IM and subcutaneous routes to BALB/c mice and Aotus monkeys. We measured specific humoral immune responses in both animal species and performed a sporozoite challenge in Aotus monkeys to assess the protective efficacy of the vaccine. After immunization both mice and Aotus seroconverted as shown by ELISA, and the specific anti-peptide antibodies cross reacted with the parasite in IFAT assays. Only two out of six immunized animals became infected after P. vivax sporozoite challenge as compared with four out of six animals from the control group. These results suggest that this TRAP fragment has protective potential against P. vivax malaria and deserves further studies as vaccine candidate.

The circulation of human astrovirus genotypes in the Central West Region of Brazil

Out of 1,588 faecal samples of children taken from three locations of the Central West Region of Brazil, 57 were positive for astroviruses (HAstVs) using reverse transcription-polymerase chain reaction (RT-PCR). They were genotyped by nested RT-PCR and/or genomic sequencing. HAstV-1 (42.8%), HAstV-2 (23.2%), HAstV-3 (3.6%), HAstV-4 (14.3%) and HAstVs -5, -6, -7 and -8 (1.8% each) were detected. In Goiânia and Campo Grande, HAstV-1 was the most frequently detected genotype while in Brasília (DF) it was HAstV-2. Shifts in the circulation of astrovirus genotypes were observed in DF and Campo Grande. All samples collected by rectal swabs were viral negative. The astrovirus genotypes were detected in all age groups and there was no correlation between genotype and age group.

Risk of dengue occurrence based on the capture of gravid Aedes aegypti females using MosquiTRAP

We assessed the risk classification of dengue fever based on the capture of Aedes aegypti adults using MosquiTRAP, a type of sticky trap, in comparison with traditional larval infestation indices. A total of 27 MosquiTRAPs were installed, with one trap per block, and were inspected weekly between November 2008-February 2009. Infestation baseline data were obtained from a survey conducted prior to trap installation. The index generated by MosquiTRAP and house index (HI) classified the area "in alert situation". The set for risk of dengue occurrence proposed by the use of MosquiTRAP classify areas in the same way of the traditional HI.

Malaria-related anaemia: a Latin American perspective

Malaria is the most important parasitic disease worldwide, responsible for an estimated 225 million clinical cases each year. It mainly affects children, pregnant women and non-immune adults who frequently die victims of cerebral manifestations and anaemia. Although the contribution of the American continent to the global malaria burden is only around 1.2 million clinical cases annually, there are 170 million inhabitants living at risk of malaria transmission in this region. On the African continent, where Plasmodium falciparum is the most prevalent human malaria parasite, anaemia is responsible for about half of the malaria-related deaths. Conversely, in Latin America (LA), malaria-related anaemia appears to be uncommon, though there is a limited knowledge about its real prevalence. This may be partially explained by several factors, including that the overall malaria burden in LA is significantly lower than that of Africa, that Plasmodium vivax, the predominant Plasmodium species in the region, appears to display a different clinical spectrus and most likely because better health services in LA prevent the development of severe malaria cases. With the aim of contributing to the understanding of the real importance of malaria-related anaemia in LA, we discuss here a revision of the available literature on the subject and the usefulness of experimental animal models, including New World monkeys, particularly for the study of the mechanisms involved in the pathogenesis of malaria.

Epidemiology and control of malaria in Colombia

Malaria is currently one of the most serious public health problems in Colombia with an endemic/epidemic transmission pattern that has maintained endemic levels and an average of 105,000 annual clinical cases being reported over the last five years. Plasmodium vivax accounts for approximately 70% of reported cases with the remainder attributed almost exclusively to Plasmodium falciparum. A limited number of severe and complicated cases have resulted in mortality, which is a downward trend that has been maintained over the last few years. More than 90% of the malaria cases in Colombia are confined to 70 municipalities (about 7% of the total municipalities of Colombia), with high predominance (85%) in rural areas. The purpose of this paper is to review the progress of malaria-eradication activities and control measures over the past century within the eco-epidemiologic context of malaria transmission together with official consolidated morbidity and mortality reports. This review may contribute to the formulation of new antimalarial strategies and policies intended to achieve malaria elimination/eradication in Colombia and in the region.

Platform for Plasmodium vivax vaccine discovery and development

Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80-100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development.