Field work in Tropical Medicine : objectives, planning and operational aspects

O trabalho de campo é de fundamental importância ao conhecimento das chamadas doenças tropicais. Ele permite estabelecer com mais precisão a prevalência das doenças endêmicas e de suas conseqüências sócio-econômicas; propicia o estudo das diversas variantes clínicas das enfermidades, dos fatores epidemiológicos desencadeantes e mantenedores de determinada condição mórbida no ambiente do campo onde ocorrem, proporcionando a investigação do agente etiológico, dos diversos reservatórios e vetores nas condições naturais de transmissão. Este artigo aborda objetivos e questões relevantes de ordem estrutural, logística e operacional no desempenho deste tipo de investigação.Field work is of fundamental importance for information regarding so-called tropical diseases. It enables more precise establishment of the prevalence of endemic diseases and of its social and economic consequences, allows study of the many clinical variants of diseases, of the epidemiological factors which trigger and maintain a certain morbid condition in the field environment where it occurs, thus enabling the investigation of the causal agent, of the diverse reservoirs and vectors in the natural conditions of transmission. This article approaches relevant structural, logistic and operational objectives and aspects in the performance of this type of investigation

Low adherence and high cost as failure factors of impregnated bed nets with insecticide for malaria control in the Brazilian Amazon

Em 1992, durante um ensaio com mosquiteiros impregnados com deltametrina, conduzido em Porto Murtinho, município de Costa Marques, Rondônia, na Amazônia Brasileira, analisou-se a aderência e os fatores econômicos capazes de reduzir o impacto do uso de mosquiteiros impregnados sobre a morbidade da malária. Os mosquiteiros impregnados tiveram excelente receptividade pela população local. No entanto, a aderência foi muito baixa, principalmente pelos adultos maiores de 15 anos de idade e, durante a estiagem. O preço do mosquiteiro impregnado foi calculado em US$18,83 para casal e, em US$13,82, para solteiro. Apesar das vantagens econômicas do emprego dos mosquiteiros impregnados em larga escala, desde que subsidiados pelas agências governamentais, a baixa aderência verificada, aliada aos fatores epidemiológicos locais, não permitem indicar o uso de mosquiteiros impregnados como medida de proteção em massa na Amazônia.In 1992 during a trial with deltamethrin-impregnated bed nets conducted in Porto Murtinho, municipality of Costa Marques, Rondonia, in the Brazilian Amazon, we investigated community compliance and the economic aspects capable of reducing the impact of this intervention on malaria morbidity. Impregnated bed nets were well accepted by the local population. However, compliance was found to be very low among adults over 15 years of age and mainly during the dry season. The cost of impregnated bed nets was US$18.83 for double-bed nets and US$13.82 for single bed nets. Despite the economic advantages of using impregnated bed nets subsidized by the government, the low compliance and local epidemiological factors do not allow to indicate the use of impregnated bed nets for mass malaria control in the Amazon region

Anorrectal lesions in HIV-positive patients using highly active antiretroviral therapy

As lesões anorretais são comuns nos pacientes positivos para o vírus da imunodeficiência humana. A terapia antirretroviral de alta efetividade tem pouca influência na progressão das neoplasias anais. Estudou-se a prevalência das lesões anorretais em 88 pacientes HIV positivos atendidos no serviço de doenças infecto-parasitárias do Hospital Universitário de Brasília, em uso de terapia antirretroviral de alta efetividade. Dados sócio-demográficos foram coletados usando um questionário pré-elaborado e os pacientes foram submetidos a exame proctológico. Cerca de 71% relataram coito anal e 30,7% estavam em uso de inibidor de protease. A prevalência das lesões anorretais foi 36,4%, sendo as mais freqüentes: condiloma acuminado e fissura anal. O condiloma acuminado foi a lesão anorretal mais prevalente e teve associação com o uso de lopinavir/ritonavir. Sugere-se o rastreamento das lesões anorretais causadas pelo papilomavírus humano nos pacientes HIV positivos/AIDS em uso de inibidor de protease.Anorectal lesions are common in patients with human immunodeficiency virus (HIV). Highly active anti-retroviral therapy (HAART) has little influence on the progression of anal neoplasms. The prevalence of anorectal lesions in 88 HIV-positive patients attended at the infectious diseases service of the University Hospital of Brasília who were using HAART was studied. Sociodemographic data were collected using a pre-prepared questionnaire and then the patients underwent proctological examination. Around 71% of the patients said they practiced anal intercourse. 30.7% were using a protease inhibitor. The prevalence of anorectal lesions was 36.4%, and condyloma acuminata and anal fissure were the most frequent of these. Condyloma acuminata was the most prevalent anorectal lesion and was strongly associated with the use of lopinavir/ritonavir. Screening for anorectal lesions caused by human papillomavirus in HIV/AIDS patients who use protease inhibitors is suggested

Bacterial and fungal colonization of burn wounds

A prospective study of fungal and bacterial flora of burn wounds was carried out from February 2004 to February 2005 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 203 patients were treated at the Burns Unit. Wound swab cultures were assessed at weekly intervals for four weeks. Three hundred and fifty four sampling procedures (surface swabs) were performed from the burn wounds. The study revealed that bacterial colonization reached 86.6% within the first week. Although the gram-negative organisms, as a group, were more predominant, Staphylococcus aureus (28.4%) was the most prevalent organism in the first week. It was however surpassed by Pseudomonas aeruginosa form third week onwards. For S. aureus and P. aeruginosa vancomycin and polymyxin were found to be the most effective drugs. Most of the isolates showed high level resistance to antimicrobial agents. Fungi were found to colonize the burn wound late during the second week postburn, with a peak incidence during the third and fourth weeks. Species identification of fungi revealed that Candida tropicalis was the most predominant, followed by Candida parapsilosis. It is crucial for every burn institution to determine the specific pattern of burn wound microbial colonization, the time-related changes in the dominant flora, and the antimicrobial sensitivity profiles. This would enable early treatment of imminent septic episodes with proper empirical systemic antibiotics, without waiting for culture results, thus improving the overall infection-related morbidity and mortality

Subdoses de primaquina associadas a recaídas de malária vivax em pacientes com peso elevado : relato de dois casos no Distrito Federal

São apresentados dois casos de pacientes com malária por Plasmodium vivax que apresentaram recaídas após tratamento com medicamentos em doses indicadas pelo Ministério da Saúde. Ambos os pacientes tinham pesos elevados e foram acompanhados no Distrito Federal, área considerada sem transmissão vetorial da doença. A cura radical foi obtida após medicação em dose proporcional ao peso corpóreo dos pacientes. __________________________________________________________________________________________________________ ABSTRACTTwo cases of malaria by Plasmodium vivax relapsed after treatment with drugs in doses recommended by the Ministry of Health are presented. Both patients were overweight and were followed in the Federal District, an area considered free from vector transmission of the disease. Radical cure was obtained after medication with the same drugs in weight proportional doses

Socioeconomic factors and attitudes towards household prevention of American cutaneous leishmaniasis in an endemic area in southern Bahia, Brazil

Foi realizado um inquérito visando identificar condições sócio-econômicas e atitudes de uma população em relação à prevenção domiciliar da LTA, na localidade de Corte de Pedra, Município de Tancredo Neves, área endêmica do sul da Bahia, Brasil. O questionário foi aplicado em julho de 1997, com perguntas sobre aspectos sociais e econômicos, hábitos e atitudes da população em relação à prevenção contra a picada de artrópodos. Foram entrevistadas 100% das famílias habitantes da área selecionada, distribuídas em 168 moradias, correspondendo a 851 pessoas. Cerca de 66,7% das famílias percebem um ou menos de um salário mínimo mensal para o sustento de uma média de 5,1 moradores por residência. A maioria das famílias (57,2%) não usa qualquer tipo de proteção. O meio de prevenção mais comum é a fumegação pela incineração de diversos tipos de materiais. As medidas de proteção individual são raramente usadas. Uma vez que na área de estudo têm sido relatadas evidências de transmissão intra e peridomiciliar de LTA, o uso de mosquiteiros impregnados com inseticida seria uma alternativa à proteção intradomiciliar.A survey was conducted to identify socioeconomic conditions and attitudes towards household prevention of American cutaneous leishmaniasis in Corte de Pedra, located in the county of Tancredo Neves, an endemic region in southern Bahia, Brazil. A questionnaire was applied in July 1997, focusing on social and economic variables, habits, and attitudes towards prevention of arthropod bites. All families (100%) living in the study area were surveyed, comprising 168 households with 851 individuals. Approximately 66.7% of the families earned up to one minimum wage, supporting an average of 5.1 residents per household. Most (57.2%) of the families did not use any type of protection against bites. Fumigation by burning various types of materials was the most customary form of prevention. Individual protection measures were rarely used. Since there was evidence of household and peridomiciliary transmission in the study area, use of impregnated bed nets is an alternative for intradomiciliary protection

Serologic assessment of yellow fever immunity in the rural population of a yellow fever-endemic area in Central Brazil

Introduction: The yellow fever epidemic that occurred in 1972/73 in Central Brazil surprised the majority of the population unprotected. A clinical-epidemiological survey conducted at that time in the rural area of 19 municipalities found that the highest (13.8%) number of disease cases were present in the municipality of Luziânia, State of Goiás. Methods: Thirty-eight years later, a new seroepidemiological survey was conducted with the aim of assessing the degree of immune protection of the rural population of Luziânia, following the continuous attempts of public health services to obtain vaccination coverage in the region. A total of 383 volunteers, aged between 5 and 89 years and with predominant rural labor activities (75.5%), were interviewed. The presence of antibodies against the yellow fever was also investigated in these individuals, by using plaque reduction neutralization test, and correlated to information regarding residency, occupation, epidemiological data and immunity against the yellow fever virus. Results: We found a high (97.6%) frequency of protective titers (>1:10) of neutralizing antibodies against the yellow fever virus; the frequency of titers of 1:640 or higher was 23.2%, indicating wide immune protection against the disease in the study population. The presence of protective immunity was correlated to increasing age. Conclusions: This study reinforces the importance of surveys to address the immune state of a population at risk for yellow fever infection and to the surveillance of actions to control the disease in endemic areas

Antimicrobial susceptibility of aerobic bacteria isolated from leishmaniotic ulcers in Corte de Pedra, BA

Um estudo prospectivo, sobre a sensibilidade antimicrobiana da flora bacteriana em úlceras cutâneas leishmanióticas, foi realizado em pacientes portadores de leishmaniose tegumentar, em Corte de Pedra, Bahia. Foram estudados 84 pacientes, principalmente adolescentes e adultos dedicados à lavoura, apresentando lesão cutânea única. Staphylococcus aureus predominou (83%) nas culturas, sendo sensível à maioria dos antibióticos testados. Flora bacteriana mista esteve presente na úlcera em 37 (44,1%) pacientes. Entre as bactérias Gram-negativas isoladas, foram mais freqüentes Enterobacter sp (13,1%), Proteus sp (8,3%), Pseudomonas aeruginosa (7,1%) e Klebsiella sp (7,1%), sendo sensíveis principalmente à ciprofloxacina, aminoglicosídeos, cefalosporinas de terceira geração e carbapenêmicos.A prospective study regarding aspects of antimicrobial susceptibility aspects was realized among patients with tegumentary leishmaniasis in Corte de Pedra, Bahia. Cases were composed mainly of adolescent and adult farmer patients with single lesions. Staphylococcus aureus predominated (83%) in the culteres with susceptibility to the majority of antibiotics. A mixed bacterial flora in ulcers was encountered in 37 (44,1%) patients. Among the gram-negative bacteria isolated, Enterobacter sp (13.1%), Proteus sp (8.3%), Pseudomonas aeruginosa (7.1%) and Klebsiella sp (7.1%) were mainly found with susceptibility to ciprofloxacin, aminoglycosides, third generation cephalosporin and carbapenems

Thrombocytopenia in malaria : who cares?

Despite not being a criterion for severe malaria, thrombocytopenia is one of the most common complications of both Plasmodium vivax and Plasmodium falciparum malaria. In a systematic review of the literature, platelet counts under 150,000/mm³ ranged from 24-94% in patients with acute malaria and this frequency was not different between the two major species that affected humans. Minor bleeding is mentioned in case reports of patients with P. vivax infection and may be explained by medullary compensation with the release of mega platelets in the peripheral circulation by megakaryocytes, thus maintaining a good primary haemostasis. The speculated mechanisms leading to thrombocytopenia are: coagulation disturbances, splenomegaly, bone marrow alterations, antibody-mediated platelet destruction, oxidative stress and the role of platelets as cofactors in triggering severe malaria. Data from experimental models are presented and, despite not being rare, there is no clear recommendation on the adequate management of this haematological complication. In most cases, a conservative approach is adopted and platelet counts usually revert to normal ranges a few days after efficacious antimalarial treatment. More studies are needed to specifically clarify if thrombocytopenia is the cause or consequence of the clinical disease spectrum

Cutaneous leishmaniotic ulcers with Corynebacterium diphtheriae

Em um estudo prospectivo para avaliar a influência da infecção bacteriana secundária na evolução da leishmaniose cutânea, em Corte de Pedra (Bahia), obteve-se o isolamento de Corynebacterium diphtheriae em 7(8,3%) de 84 pacientes portadores de úlceras, avaliados. Devido ao pequeno número de pacientes com a presença da bactéria na úlcera, não foi possível concluir se Corynebacterium diphtheriae comporta-se apenas como colonizante, nem sobre a sua influência no processo de cicatrização da úlcera leishmaniótica.In a prospective study to evaluate the influence of secondary bacterial infection on the evaluation of cutaneous leishmaniasis, in Corte de Pedra (Bahia), we isolated Corynebacterium diphtheriae in 7 (8.3%) out of 84 patients with ulcers studied. Due to the small number of patients with the presence of the bacteria in the ulcer, we could not conclude whether Corynebacterium diphtheriae behaves only as a colonizer nor its influence on the healing of the leishmaniotic ulcer