The ecology of Triatoma sordida in natural environments in two different regions of the state of Minas Gerais, Brazil

A study was undertaken about T. sordida in the natural environment in two different regions of the state of Minas Gerais: Itapagipe (Triângulo), an area of cerrado modified by the formation of fields of pasture and agriculture, and Mato Verde (north) an area of transition between caatinga and cerrado with profound deforestation in the last years due to the expansion of cotton cultivation. In both regions the principal ecotopes identified were hollow trees and the bark of live or dead trees, where the occurrence of a food source is not frequent. In this environment, the triatomines utilize various food sources; opposums appear to represent an important source of infection. In the north of Minas, a greater concentration of reservoirs and vectors was observed than in the Triángulo which could explain the higher level of infection of the triatomines in the north. Close attention to the process of domiciliation of T. sordida in the north of Minas is recommended where an extensive intervention by man in the natural environment has occurred and where a rise in the population of triatomines in the peridomestic environment has been observed in recent years.

The frequency of blood-born viral infections in a population of multitransfused Brazilian patients

The frequency of viral markers for hepatitis B (HBV) and C (HCV), human immunodeficiency virus-1 (HIV-1) and human T-lymphotropic virus-1 (HTLV-1) was evaluated in 32 Brazilian ß-thalassemia multitransfused patients. Additionaly the serum concentrations of ferritin and alanine aspartate transaminase (ALAT) were determined. The results show a high prevalence of markers of infection by HBV (25.0%) and HCV (46.8%) and a low prevalence of markers for HIV-1 and HTLV-1. No correlations were demonstrated between the presence of the hepatitis markers and the number of units transfused or the serum concentrations of ferritin and ALAT.

Comparative study on the localization of adult Schistosoma mansoni worms in albino mice anesthetized with pentobarbital sodium, ether or chlorophorm

The effect of anesthetic drugs on the localization of adult worms in albino mice was compared. The animals with 56 days of infection were anesthetized with pentobarbital sodium, ether or chlorophorm. Perfusion was carried out immediately after, recovering the worms and classifying them in relation to their localization on the liver or portal vein and the mesenteric veins. Our results showed that pentobarbital sodium produced a greater displacement of the worms to the liver (89%) than ether (76%) and chlorophorm (34%) did, when compared to the control group (22%). The difference between pentobarbital sodium and ether was significant (p < 0.05). We suggest that anesthetic drugs may not be used in studies on the distribution of adult worms in several hosts.

Experimental pulmonary schistosomiasis: lack of morphological evidence of modulation in schistosomal pulmonary granulomas

Numerous pulmonary schistosome egg granulomas were present in mice submitted to partial portal vein ligation (Warren's model). The granulomas were characterized by cellular aggregations formed within alveolar tissue. Main cellular types were macrophages (epithelioid cells), eosinophils, plasma cells and lymphocytes. These cells were supported by scanty fibrous stroma and exhibited close membrane contact points amongst themselves, but without forming specialized adhesion apparatus. When granulomas involved arterial structures, proliferation of cndothelial and smooth muscle cells occurred and fibrosis associated with angiogenesis became more evident. Granulomas formed around mature eggs in the pulmonary alveolar tissue presented approximately the same size and morphology regardless of the time of infection, the latter being 10, 18 and 25 weeks after cercarial exposure. This persistence of morphological appearance suggests that pulmonary granulomas do not undergo immunological modulation, as is the case with the granulomas in the liver and, to a lesser extent, in the intestines. Probably, besides general immunological factors, local (stromal) factors play an important role in schistosomal granuloma modulation.

Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP": during a five year period (1988-1993)

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serologycal assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993,18 (25.71 %) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

Investigation on the possibility of spontaneous cure of mice infected with different strains of Trypanosoma cruzi

Seventy Swiss mice chronically infected with different strains of Trypanosoma cruzi, with persistently negative parasitemia on routine blood examination were parasitologically investigated to find out whether spontaneous cure occurred. Duration of infection varied from 90 to 250 days in the initial phase of this investigation. Parasitological tests consisted of daily direct blood examination performed during at least 25 days, followed by xenodiagnosis and subinoculation of blood into newborn mice. Mice that persisted negative were treated with Cyclophosphamide with one dose of 250 mg/kg of body weight and then investigated by direct blood examination, xenodiagnosis and subinoculation. A second dose of 250 mg/kg b. w. was given to the persistently negative mice. With one single exception, all mice showed positive parasitological tests in the different stages of the present investigation and we conclude that spontaneous cure did not occur in this group, which is representative of the chronic infection with different strains of T cruzi.

Production of Shistosoma mansoni cercariae by Biomphalaria glabrata from a focus in Belo Horizonte, Minas Gerais

The snail density, levels of infection and the monthly production of Schistosoma mansoni cercariae by Biomphalaria glabrata were determined in a focus of Barreiro de Baixo (Belo Horizonte, MG, Brazil). During a period of 38 months (1984 to 1987) 5,366 snails were collected of which 324 (6.03%) were infected with S. mansoni. The total number of cercariae shed was 5,667,312. Each snail shed an average of 17,422 cercariae during the time that it was under study in the laboratory. The greatest longevity of infected snails was 218 days. Natural cure was observed in 42 (12.9%) of the infected specimens about 130 days after collection. The average snail density in the focus during the period of study was 16.3 snails per scoop. The shedding of cercariae by snails collected from the field was compared with laboratory bred specimens infected in mass with the LE strain of S. mansoni from Belo Horizonte. The laboratory infected snails shed an average of 6,061 cercariae each, a value 2.8 times less than the field specimens due to a shorter life span. The prevalence of schistosomiasis in the focus was 14.3%.

Clinical-epidemiologic study of schistosomiasis mansoni in Ponte do Pasmado, a village in the municipality of Itinga, State of Minas Gerais, Brazil, 1992

A clinical-epidemiologic study of schistosomiasis mansoni was conducted in the population of Ponte do Pasmado, a village in the municipality of Itinga, state of Minas Gerais, Brazil. Faecal Parasitology by the Kato-Katz method and clinical examination were performed in 93.8% and 82.8% of the local population, respectively. A socioeconomic survey was also made and the signs and symptoms presented by the patients were recorded, as well as their contacts with natural waters. The rate of Schistosoma mansoni infection was 50.3%; the peak of infection occurred during the second decade of life; there was a predominance of low egg counts in faeces (85.89% of positive patients eliminated less than 500 eggs per gram of faeces); the splenomegaly rate was 1.23%. When the risk factors for S. mansoni infection were studied, significant risks were detected in activities such as fetching water, washing dishes, bathing, and crossing streams.

Natural killer cell activity in experimental paracoccidioidomycosis of the Syrian hamster

The study evaluated the activity of NK cells during the course of experimental infection of hamsters with Paracoccidioides brasiliensis. Eigthy hamsters were infected with P. brasiliensis by intratesticular route and sacrificed at 24h, 48h, 96h, 1, 2, 4, 8 and 11 weeks of infection and compared to 40 noninfected hamsters employed as controls. These animals were submitted to the study of NK cytotoxic activity by a single-cell assay and humoral immune response by immunodiffusion and ELISA tests. The production of macrophage migration inhibitory factor in the presence of Phyto-hemagglutinin and P. brasiliensis antigen and histopathology of the lesions were evaluated at 1, 4, 8 and 11 weeks of infection. The infected animals displayed significantly high levels of NK activity during the four weeks of infection that decreased from the 8th week on when compared to controls. This impairment of NK activity was associated with depression of cell-mediated immune response and with increase in the extension of the histopathologic lesions. There was an inverse correlation between NK cell activity and specific antibody levels. The results suggest that after initial activation, NK cells were unable to control the fungus dissemination. The impairment of NK activity in the late stages of the infection might be related to immunoregulatory disturbances associated with paracoccidioidomycosis.

Development of Schistosoma mansoni in Biomphalaria tenagophila, Biomphalaria straminea and Biomphalaria glabrata

A comparative study of the development of Schistosoma mansoni during the intra-molluscan phase was made by means of histological sections of Biomphalaria tenagophila, B. straminea and B. glabrata from Brazil. Two hundred snails of each species were individually exposed to 50 miracidia of the S. mansoni, AL line. No larvae were observed in the snails fixed 72 h after exposure. In specimens shedding cercariae, 31 days after exposure tissue reactions encapsulating the larvae were seen in B. tenagophila and B. straminea, in the head-foot, mantle collar and renal ducts. No tissue reactions occurred in the digestive glands of these two species. In B. glabrata the presence of numerous sporocysts and cercariae without tissue reactions was observed in the digestive gland, and other organs. The levels of infection of the snails and the average numbers of cercariae shed per day were 32.6% and 79±90 respectively for B. tenagophila, 11.3% and 112±100 for B. straminea and 75.3% and 432±436 for B. glabrata. The lower levels of infection and average numbers of cercariae shed by B. tenagophila and B. straminea are thus related to their more potent internal defense systems.

Schistosomiasis: predisposing cause for the formation of hepatic abscesses? Case report

An adult patient with chronic schistosomiasis from an endemic area, complained about a seven day fever, along with jaundice and lumbar backache on the right side. Image exams showed multiple pyogenic liver abscesses. All the classic etiologies were discarded through clinical, radiological and laboratorial criteria. Schistosomiasis can cause pylephlebitis as a complication, along with immunesuppression, granulomatous reaction with central lobular liver necrosis and a greater risk of infection. The authors suggest that schistosomiasis in its chronic form may be the predisposing cause of multiple pyogenic liver abscesses, especially in endemic areas.

Aerobic bacteria, Chlamydia trachomatis, Pneumocystis carinii and Cytomegalovirus as agents of severe peneumonia in small infants

The authors studied 58 infants hospitalized for pneumonia in a semi-intensive care unit. Age ranged from 1 complete to 6 incomplete months. The infants were sent from another hospital in 20 cases and from home in a further 38. Pulmonary involvement, which was alveolar in 46 cases and interstitial in 12, was bilateral in 31 children. The investigation was carried out prospectively on the etiological agents associated with respiratory infection to look for evidence of aerobic bacteria (blood cultures), Chlamydia trachomatis and Cytomegalovirus (serology), and Pneumocystis carinii (direct microscopy of tracheal aspirated material). The following infectious agents were diagnosed in 21 children (36.2%): Aerobic bacteria (8), Chlamydia trachomatis (5), Pneumocystis carinii (3), Cytomegalovirus (3), Cytomegalovirus and Chlamydia trachomatis (1), Aerobic bacteria and Cytomegalovirus (1). Seven cases of infection by Chlamydia trachomatis and/or Cytomegalovirus were diagnosed out of the 12 cases with pulmonary interstitial involvement.

Active replication of hepatitis B virus (HBV) in HIV type 1 and in HIV type 2 infected patients

To evaluate the effect of concurrent infection by HIV on HBV infection or immunity, we have studied a group of 66 HIV1+ symptomatic Caucasian patients and another of 38 African HIV2+ asymptomatic individuals, concerning their HBV status: serological markers of infection and presence of HBV-DNA in serum, the last taken as sign of hepatitis B virus active replication, were monitored. HIV+ groups were compared with seronegative controls, adequately matched for age, sex and ethnological background. HBV DNA was found in 7.6% of HIV1+ Caucasian patients and 3.2% of seronegative controls; in African HIV2+ individuals 2.6% were also HBV DNA+, a percentage close to that found in HIV2 seronegative controls (2.9%). No correlation was found between HIV infection and HBV active replication. Immunodepression that follows HIV infection over time may be compatible with a degree of T cell function capable of avoiding reinfection with or reactivation of HBV, even in symptomatic stages of acquired immunodeficiency syndrome. Our findings are relevant to the choice of preventive strategies in populations at risk for HIV and HBV infection.

New records of Histoplasma capsulatum from wild animals in the Brazilian Amazon

Twenty-eight isolates of Histoplasma capsulation were obtained from eight species of forest mammals from the States of Amazonas, Pará and Rondônia in the Amazon Region of Brazil. Primary isolates were obtained by inoculating triturated liver and spleen tissue intradermally and intraperito-neally in hamsters. Mycological diagnosis in hamsters presenting lesions was confirmed by histopathology and culture on Sabouraud dextrose-agar. Infected hamsters developed signs of disease within two to nine months; all had disseminated visceral lesions and most also had skin lesions at the sites of inoculation. None of the hamsters inoculated with skin macerates of the original hosts developed histoplasmosis, and histopathological examination of the viscera of the wild hosts failed to reveal H. capsulation. Prevalence of infection was considerably higher in females than in males both for the opossum Didelphis marsupialis and for total wild animals (479) examined. It is proposed that canopy-dwelling mammals may acquire the infection from conidia borne on convective currents in hollow trees with openings at ground-level.

HANTAVIRUS PULMONARY SYNDROME IN THE PROVINCE OF RIO NEGRO, ARGENTINA, 1993-1996

Early in 1995 the first case of Hantavirus Pulmonary Syndrome was serologically confirmed in El Bolsón (Province of Río Negro, Argentina), corresponding to the third outbreak reported in Argentina. A total of 26 cases of HPS related to the Andean region of Rio Negro Province, were reported from 1993 to 1996, 17 in El Bolsón, 4 in San Carlos de Bariloche, and 5 in Buenos Aires. The incidence rate was 5.03 x 100000 with a mortality rate of 51.85 x 100. The occurrence of cases was mainly seasonal, with a significantly greater number in the spring, and the persons affected mainly lived in urban or periurban areas. In four cases, the affected individuals were members of a couple, spouses or live-in contacts. Seven cases were Health workers (physicians, nurses or administrative staff). Twelve cases were related among them, due to an outbreak of 80 days. Two of them did not visit the Andean region. A total of 139 rodents were captured and seven of them, Olygoryzomys longicaudatus, were found to be serologically positive. The possibility of infection by contact with rodents or fecal matter is being analyzed and also hypothesis related with interhuman transmission