RESUMO
Eighteen patients from the northeastern Brazilian State of Ceara with proven kala-azar were studied for evidence of skin parasitism: two had ulcerative or papular skin lesions and 16 had clinically normal skin. Punch biopsies (3 mm) of intact paraspinal subscapular skin were performed on all patients; in those with papular or ulcerative lesions biopsies also were taken from an active site. One of each of the subscapsular biopsies and half of each biopsy from an active lesion were studied; the other specimens were seeded on NNN Difco Blood Agar Base Medium for parasite culture. The biopsies revealed a discrete to intense mononuclear inflammatory infiltrate, predominantly perivascular in nature. No amastigotes were observed in any tissue sections but 7 of the 18 patients yielded promastigotes on skin culture identified by monoclonal antibodies and by enzyme electrophoresis as Leishmania (Leishmania) chagasi [L. (L.) chagasi]. The isolation of Leishmania (Leishmania) chagasi, the recognized aetiologic agent of visceral leishmaniasis in the New World, from the skin of nearly 40% of 18 AVL patients proves dermatotropism of L. (L.) chagasi occurs and may be frequent in neotropical human visceral leishmaniasis (AVL.). Infected persons with skin parasites could act as a reservoir of infection and allow human to human transmission.
Assuntos
Leishmania donovani/isolamento & purificação , Leishmaniose Visceral/parasitologia , Pele/parasitologia , Adolescente , Adulto , Animais , Brasil , Criança , Pré-Escolar , Humanos , Leishmaniose Visceral/patologia , Masculino , Pele/patologiaRESUMO
In laboratory tests, four different strains of Mesocyclops aspericornis (Daday) collected in or near Fortaleza, Brazil, showed potential as biological control agents of Aedes aegypti (L.) mosquito larvae but were not as effective against Anopheles or Culex. In contrast, the larger M. longisetus (Thiebaud), collected at Fortaleza, killed 100% of Ae. aegypti and Anopheles farauti (Laveran) (No. 1) at larval densities of 200/liter and Culex quinquefasciatus (Say) at 25/liter. In cage simulations with Ae. aegypti and Mesocyclops, both copepod species eliminated all immatures in earthenware pots by week 3. Owing to the lack of replacement, all Ae. aegypti adults subsequently died by week 8 or 9. Although both M. longisetus and M. aspericornis showed maximum reproductive potential at 25 degrees C, breeding occurred from 20 to 35 degrees C. Based on these laboratory evaluations, M. longisetus has been selected for field trials in rural villages in Ceará to control Ae. aegypti.
Assuntos
Aedes , Crustáceos/fisiologia , Controle Biológico de Vetores , Animais , BrasilRESUMO
The evolution of Chagas' cardiomyopathy is poorly understood. We therefore examined the development of cardiac lesions in a rural Brazilian community for a period of 7 years. Initially, 42% of 1017 residents were seropositive for infection with Trypanosoma cruzi. Age-specific infection rates indicated that most had become infected before the age of 20 years. On follow-up, it appeared that those persons who developed cardiac lesions did so soon after infection, since the incidence of right bundle branch block and other ventricular conduction defects (VCDs) was also highest before age 20 years. The progressive nature of these lesions was demonstrated by frequent development of additional electrocardiographic abnormalities and high mortality among infected adults with VCDs. In contrast, mortality was low and approximately the same for seropositive and seronegative adults under 60 years who had normal electrocardiograms. Electrocardiography during the early asymptomatic stage of infection was able to distinguish persons with potentially lethal cardiac lesions from those with a benign prognosis.
Assuntos
Cardiomiopatia Chagásica/epidemiologia , Fatores Etários , Anticorpos/análise , Brasil , Cardiomiopatia Chagásica/diagnóstico , Cardiomiopatia Chagásica/mortalidade , Eletrocardiografia , Seguimentos , Humanos , Estudos Prospectivos , População Rural , Trypanosoma cruzi/imunologiaAssuntos
Saúde da População Rural , Esquistossomose mansoni/transmissão , Abastecimento de Água , Adolescente , Adulto , Fatores Etários , Idoso , Brasil , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Esquistossomose mansoni/epidemiologia , Esgotos , Fatores Socioeconômicos , Microbiologia da ÁguaRESUMO
An outbreak of 20 cases of acute Chagas' disease followed the movement of Triatoma infestans into the county of Riacho de Santana, Bahia, Brazil. The outbreak was unusual in that the majority of cases occurred in adults. Vector control measures were implemented. Three years after the outbreak, a rural community was examined to determine the extent of human infection and disease due to Trypanosoma cruzi. Ninety of 440 residents (20.5%) had serologic evidence of infection, but rates of electrocardiographic (EKG) abnormalities were low. Comparison of age-specific rates of seropositivity and EKG abnormalities with rates from areas with endemic Chagas' disease supported the hypothesis of a recent epidemic. Control measures appear to have interrupted transmission in the region.
Assuntos
Doença de Chagas/epidemiologia , Surtos de Doenças , Adulto , Idoso , Anticorpos/análise , Brasil , Cardiomiopatia Chagásica/epidemiologia , Doença de Chagas/transmissão , Criança , Pré-Escolar , Estudos Transversais , Humanos , Lactente , Controle de Insetos , Insetos Vetores , Pessoa de Meia-Idade , População Rural , Triatoma , Trypanosoma cruzi/imunologiaRESUMO
This prospective study has shown that oxamniquine treatment controlled endemic schistosomiasis mansoni in a defined rural population in Castro Alves, north-east Brazil. Data before and after treatment spanning 11 years were collected for a cohort of 191 residents. Before treatment (1974-77), the cohort was heavily infected and the prevalence of associated hepatomegaly (greater than 86%) and splenomegaly (greater than 17%) was stable. The cohort was treated when oxamniquine became available in 1977; during the next 8 years, over 80% received further treatments from the Brazilian programme for the control of schistosomiasis. With treatment, the incidence of splenomegaly fell (10% to 2%) and the splenomegaly regression rate increased (43% to 91%). Declining disease rates were coincident with substantial falls in the prevalence and intensity of Schistosoma mansoni infections. The final prevalence rates for hepatomegaly (31%) and splenomegaly (3%) in Castro Alves approached the corresponding rates of 10% and 1% in a comparable uninfected control population.
Assuntos
Nitroquinolinas/uso terapêutico , Oxamniquine/uso terapêutico , Esquistossomose mansoni/prevenção & controle , Adolescente , Adulto , Brasil , Criança , Fezes/parasitologia , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Exame Físico , Estudos Prospectivos , População Rural , Esquistossomose mansoni/epidemiologiaRESUMO
A cross-sectional study of morbidity associated with Schistosoma mansoni infection in an area in North-East Brazil where the disease is endemic was carried out in 1974. The survey was repeated in 1977, before mass treatment with oxamniquine, providing a cohort of 210 individuals who had both examinations. The high prevalence of hepatomegaly (over 80%) and of splenomegaly (over 15%) contrasted with rates of 10% and 1%, respectively, in a non-endemic area. Over the 3-year period hepatomegaly spontaneously regressed in 13% of patients, and splenomegaly regressed in 56%, a phenomenon most common in older individuals with light infections. Those with heavy infections--ie, 500 or more eggs per g faeces, had an excess risk of splenomegaly of 19.6% and, of its persistence, of 61.5%. Thus, intensity of infection was a critical factor in liver and spleen involvement, and programmes of chemotherapy that reduce infection should mitigate the risk of schistosomal morbidity.
Assuntos
Esquistossomose/epidemiologia , Adolescente , Adulto , Brasil , Criança , Pré-Escolar , Estudos Transversais , Hepatomegalia/etiologia , Hepatomegalia/patologia , Humanos , Oxamniquine/uso terapêutico , Estudos Prospectivos , Schistosoma mansoni , Esquistossomose/complicações , Esquistossomose/tratamento farmacológico , Esquistossomose/patologia , Esplenomegalia/etiologia , Esplenomegalia/patologiaRESUMO
Oral oxamniquine was tested as a control strategy for endemic schistosomiasis in a rural area of Bahia, Brazil. Adults were treated with a single dose (12.5 to 15 mg per kg) and children (less than 12 years old) with a total of 20 mg per kg in two doses. The 191 (infected) persons treated represented 69% of the infected population in the study area. Follow-up stool examinations (Kato-Katz method) at one, 3, 6, 13, 25 and 33 months showed the cure rate declining from 80% at three months to 46% at 33 months. Over one half of those not cured showed a decrease in egg counts throughout the follow-up which, after 33 months, remained 66% below the pre-treatment levels. Stool examinations conducted on all study area residents during three years before chemotherapy showed the prevalence and intensity of Schistosoma mansoni infection to be high and stable. 33 months after the chemotherapy the prevalence was 41% and for infected individuals the geometric mean egg count was 121 epg, a decline of respectively 35% and 40% from pre-treatment levels for each index. Chemotherapy of infected persons with oxamniquine protected the community as a whole from high worm burdens for almost three years, although at this point the prevalence began to rise towards pretreatment levels.