Toxoplasmose congênita

We had the opportunity to study 6 cases of the congenital form of toxoplasmosis, found in a series of 1200 necropsies of fetuses and newborn babies, realized at 3 different hospitals in Rio de Janeiro, Brazil. Among the 6 cases, 4 were premature babies liveborn at the 6th-8th gestational month and 2 were stillborn (1 premature and 1 at term). In all those cases, the diagnosis was based in the detection of the parasite in tissues and in one case it was even isolated the Toxoplasma from the necrotic material found in the cranial cavity. This strain of Toxoplasma, pathogenic to pigeons, to guinea pigs and to mice, is preserved by successive transfers in mice. Some facts observed in those cases present an interest not only strictly anatomic but also have certain value for the better acknowlegment of the disease. First, we want to call the attention to the presence of a sudden high fever, during or just before pregnancy in the 4 cases in which the maternal anamnesis was perfectly studied; this fever that was preceded by a normal beginning of pregnancy, had relatively rapid remission, but in 2 cases was immediately followed by uterine bleeding and premature delivery, although the puerperium had been apparently normal. It is known that are normal the subsequent children of the mothers that delivered a baby with toxoplasmosis and that several women have normal babies before the toxoplasmotic one. We believe that the fever observed in our cases could be indicative of the beginning of maternal infection and those are the reasons why we emphasize the need of careful anamnesis, specially in the cases actually diagnosed as inapparent infection. Another fact to notice is that in 5 of our cases the event premature delivery happened always between the 6th and the 8th months of pregnancy, and the only term fetus was delivered in advanced stage of maceration. The above mentioned facts could agree with the opinion of FRENKEL (1949), when he declared that "primary infection of the pregnant mother appears more likely to be the commoner mode of fetal toxoplasmic infection", but they would disagree with WEINMAN (1952) who believes that the transmission of Toxoplasma to the fetus is more frequent through a pregnant woman with chronic disease and who says "that infection contracted during pregnancy may and probably does happen from time to time"...Still in connection with the transmission of toxoplasmosis, we want to note the verification of inflammatory lesions in the placental villi and in the umbilical cord in 3 of the 4 cases in which such organs were examined at the microscope. In the case n. 1, we found several pseudocysts of Toxoplasma in the placenta, and the fibroblasts of Wharton's jelly were particularly rich in isolated forms and in colonies of Toxoplasma; the easy multiplication of the parasite in that tissue calls the attention and even suggests its utilisation for Toxoplasma's cultivation. The confirmation of Toxoplasma in human placenta was made only recently by CRISTEN et al. (1951) and by NEGHME et al. (1952), in Chile; it is not frequent in the literature, what gives some value to our present verification. Another observation was that provided by the case n. 6. This baby, a premature one of the 6th month, was 14 days old and-died with signs of respiratory disease, the causa mortis have been pneumonia. At the necropsy, we found no gross change that suggested toxoplasmosis, except the presence of some small necrotic focuses in the cerebral nervous substance around the ventricles. As a matter of fact, there was no enlargement of spleen or liver and neither leptomeningitis nor hydrocephalus. Such focuses were attributed to possible anoxia and in fact they are extremely similar to anoxial softenings, even when they are examined at the microscope; its structure composed of a central necrotic zone, surrounded by proliferated neuroglia and by a variable deposit of calcium salts, closely simulated the anoxial softenings, when the microscopical examination is based in the common histological preparations (hematoxilin-eosin, etc.). But when we examine preparations by the Giemsa or by the periodic acid-Schiff methods, we will note the presence of Toxoplasma, with its typical aspect or a little changed by degeneration. When we describe this observation, we wish to evidence the need of the search of Toxoplasma and closed parasites, in the cases of supposed pure anoxial softenings of nervous substance, in children. The frequency with which the congenital toxoplasmosis was anatomically verified should be emphasized, although the disease had not been clinically suspected, and it should be borne in mind that the second case of toxoplasmosis reported in the world was observed in Brazil by MAGARINOS TORRES; this case was the first to be described of the generalized congenital form of the infection, i. e. with myocardial lesions and parasites in skeletal muscles and skin.

Cutaneous leishmaniasis in frequent in equines from an endemic area in Rio de Janeiro, Brazil

In an endemic area of cutaneous leishmaniasis in Rio de Janeiro State where a mule had been found infected, a systematic search among equines was performed, resulting in the detection of Leishmania parasites in skin lesions of 30.8% of the animals, which included horses and mules. The eventual role of equines in the epidemiology of the human disease is being investigated.

Studies on survival, biological activities and behavior of Biomphalaria glabrata, the host snail of Schistosomiasis, submitted to increased hydrostatic pressure: a technique

To study changes in survival, in biological activities and behavior of planorbids submitted to increased hydrostatic pressure, we developed a technique using two transparent chambers and a hydraulic piston. The apparatus permitted renewal of the liquid medium without substantial variations in pressure, thus eliminating excretion products and maintaining the desired O2 level and thereby permitting us to evaluate the effects of pressure independently of the occurrence of anoxia. Pressure was maintained without any contact of the liquid medium with compressed air, a situation which reproduced with relative fidelity what occurs in nature and assured the presence of the same amounts of gases in the two observation chambers (Control and Experimental). Biomphalaria glabrata was found to be able to survive at least 48 hours when submitted to 49.02 x 10**4 Pa (equivalent to a water depth of 48.8 m), continuing to day egg masses and showing few behavioral changes when compared with the control group.

The efficiency of Lutz, Kato-Katz and Baermann-Moraes (adapted) techniques association to the diagnosis of intestinal helmints

The association of Lutz/Kato-Katz and Lutz/Bermann-Moraes (adapted techniques was used to improve better results that ranged from 0.4 to 11 times in the search of eggs of Ascaris lumbricoides, Schistosoma mansoni, Trichiuris trichiura, Taenia sp. and larvae of Strongyloides stercoralis.

Antitumor activity of chemical modified natural compounds

Search of new activity substances starting from chemotherapeutic agents, continously appears in international literature. Perhaps this search has been done more frequently in the field of anti-tumor chemotherapy on account of the unsuccess in saving advanced stage patients. The new point in this matter during the last decade was computer aid in planning more rational drugs. In near future "the accessibility of supercomputers and emergence of computer net systems, willopen new avenues to rational drug design" (Portoghese, P. S. J. Med. Chem. 1989, 32, 1). Unknown pharmacological active compounds synthetized by plants can be found even without this eletronic devices, as tradicional medicine has pointed out in many contries, and give rise to a new drug. These compounds used as found in nature or after chemical modifications have produced successful experimental medicaments as FAA, "flavone acetic acid" with good results as inibitors of slow growing animal tumors currently in preclinical evaluation for human treatment. In this lecture some international contributions in the field of chemical modified compounds as antineoplasic drugs will be examined, particularly those done by Brazilian researches.

A study on the pathogenesis of human cerebral malaria and cerebral babesiosis

Cerebral complications are important, but poorly understood pathological features of infections caused by some species of Plasmodium and Babesia. Patients dying from P. falciparum were classified as cerebral or non-cerebral cases according to the cerebral malaria coma scale. Light microscopy revealed that cerebral microvessels of cerebral malaria patients were field with a mixture of parazited and unparazited erythrocytes, with 94% of the vessels showing parasitized red blood cell (PRBC) sequestration. Some degree of PRBC sequestration was also found in non-cerebral malaria patients, but the percentage of microvessls with sequestered PRBC was only 13% Electron microscopy demonstrated knobs on the membrane of PRBC that formed focal junctions with the capillary endothelium. A number of host cell molecules such as CD36, thrombospondim (TSP) and intracellular adhesion molecule I (ICAM-1) may function as endothelial cell surfacereports for P. falciparum-infected erythrocytes. Affinity labeling of CD36 and TSP to the PRBC surface showed these molecules specifically bind to the knobs. Babesia bovis infected erythrocytes procedure projections of the erythrocyte membrane that are similar to knobs. When brain tissue from B. bovis-infected cattle was examined, cerebral capillaries were packed with PRBC. Infected erythrocytes formed focal attachments with cerebral endothelial cells at the site of these knob-like projections. These findings indicate that cerebral pathology caused by B. bovis is similar to human cerebral malaria. A search for cytoadherence proteins in the endothelial cells may lead to a better understanding of the pathogenisis of cerebral babesiosis.

New approaches for the control and eradication of schistosomiasis in Venezuela

Schistosomiasis in Americawith the exception of Brazil, behaves as a chronic mild disease with few clinical manifestations due to low parasite burden. These features restrict the clinical and parasitological diagnosis. The most commonly used stool examination method, Kato-Katz, becomes intensitive when the majority of individuals excrete less than 100 eggs/g of feces. In view that antigen-detecting techniques have not been able to reveal light infections, the antibody detecting assays remain as a very valuable diagnostic tool for epidemiological surveillance. The Venezuelan Schistosomiasis Research group (CECOICE) has designed a mass chemotherapy strategy based on sero-diagnosis. Since blood sampling is one of the important limitating factors for large seroepidemiological trials we developed a simple capillary technique that sucessfully overcomed most of the limitations of blood drawing. In this sense, ELISA seems to be the most adecuate test for epidemiological studies. Soluble egg Schistosoma mansoni antigen (SEA) has been largely used in Venezuela. The sensitivity ELISA-SEA in our hands is 90% moreover its specific reach 92% when populations from non-endemic areas but heavily infected with other intestinal parasites are analyzed. The Schistosomiasis Control Program is currently carrying out the surveillance of endemic areas using ELISA-SEA as the first screening method, followed by the Circumoval Precipitin test for validation assay. The results with these two serological techniques allowed us to defined the criteria of chemotherapy in populations of the endemic areas. On the search of better diagnostic technique, Alkaline Phosphatase Immunoenzyme Assay (APIA) is being evaluated in field surveys.

Parasitological diagnosis of schistosomiasis mansoni: fecal examination and rectal biopsy

Even with all progress in the search of sensitive and methods for the immunological diagnosis of schistosomiasis, the microscopic detection of eggs of the parasite in the stool still remains the most widely used tool for the actual diagnosis of active infection. Among the coproscopic methods, Kato's technic modified by Katz et al (Kato/Katz) has the advantages of higher sensitivity, the possibility of egg quantification, its low operational cost and its feasibility in areas with minimal infra-structure. The oorgram of the rectal mucosa is valuable in initial clinical trials of schistosomicides, when it is needed to observe egg morphology in tissue. It could be an alternative method for individual diagnosis, being more sensitive than a single stool exam in low intensity infection. However, the increased sensitivity of a higher number of fecal exams makes that invasiveprocedure unnecessary. In the assessment of cure of schistosomiasis, Kato/Katz method (three fecal samples in one, three and six months after treatment) and the rectal biopsy four months after treatment, are equally reliable.

Imunodiagnóstico

In the last years, the knowledge about immunodiagnosis in schistosomiasis has increased considerably. This was due to a better immunologic understanding of the host-parasite interaction and the evolution of the technical procedures by the introduction of new concepts and techniques. The search of more sensitive, specific, practical and less expensive diagnostic tests has led to the development of a great number of immunological tests that could complement the limitations of the parasitological diagnosis. The antigens of differnt life cycle stages of Schistosoma mansoni may be used as target for immunodiagnostic tests and the anti-schistosome antibodies in sera of infected patients can be detected. The research of circulating schistosome antigens, the production of specific antisera and the application of these antibodies in immunodiagnostic tests have also been discussed.

A modified assay for measuring thymocyte co-stimulatory activity

The observation that murine thymocytes increase their proliferation to interleukin 1 (IL-1) in the presence of phytohemagglutinin (PHA) when pre-incubated with interleukin 2 (IL-2) allowed the introduction of a modified assay for the measurement of IL-1 or the search of thymocyte-inducing proliferative activities in biological samples. Pre-incubation of thymocytes for 24 hr with 50 u/ml IL-2, followed by washings, elicited their maximal response to IL-1 in the usual lymphocyte activating factor (LAF) assay. This suggests that sequential events lead to thymocyte activation. The responsiveness is three to five fold greater than, and the total time of assay is the same as that of the LAF assay. Interestingly, pre-incubation with IL-2 renders thymocytes more sensitive than responsive to crude monocyte conditioned media. The use of the MTT colorimetric method for the assessment of thymocyte proliferation, and of the lectin jacalin as a co-mitogen are suggested as alternatives to be used in co-stimulatory assays.

Comparative evaluation of a simple and sensitive assay for detection of orthomyxo and paramyxoviruses

Studies were done to evaluate comparatively the traditional HA assay and a more recently introduced lectin-neuraminidase (LN) methodologyin search of a simple and sensitive assay for virus detection during laboratorial diagnosis. The results proved the value of LN assay as a sensitive methodologyfor detection of virus particles, presenting results at least equal to those obtained by HA (hemagglutination) assay, with significant values of accumulated frequencies for LN/HA factors (ratios between LN and HA titers) higher than two. The accumulated values of frequencies for LN/HA factors as high as four were very significant, 72.7 (per cent) for influenzavirus and 60.7 (per cent) for Newcastle disease virus (NDV), moreover accumulated frequencies for LN/HA factors even as high as 32 were due to influenzavirus (45.4 per cent) and NDV (7.2 per cent) samples. After the storage period, most of those concentraded samples that even did not present HA titers could be detected through LN assay, demonstrating a lower threshold for virus detection.

Biologia do Rhodnius pictipes Stal, 1872 em condições de laboratório (Hemiptera, Reduviidae, Triatominae)

Rhodnius pictipes Stal, 1872 is a silvatic species with a widespread distribution in South America, found in nine Brazilian states, naturally infected by Trypanosoma cruzi and T. rangeli. The individual rearing of this species under laboratory conditions, allowed the following biological aspects to be observed: incubation time, search for first meal after eclosion or moult, time - lapse between presentation of the blood meal and the beginning of feeding, duration of blood meal, time and place of defecation, number of blood meals, duration of each instar and adult longevity, and time required from egg to adult.

Schistosomiasis control in the State of São Paulo

The program of schistosomiasis control for the State of São Paulo, where only low endemicity areas occur, is discussed in this paper. Inclusion of schistosomiasis among the diseases due to obligatory notification is considered as a measure of great importance. Accordingly the search for passive cases conducted by the public health system acquired major importance in the disease surveillance. As from 1981 to 1992 only 11% of the detected cases were considered as autochthonous. The main transmission areas are located at the Litoral and Paraiba Valley regions. In the period of time under analysis, the epidemiological surveillance data suggest a decrease in the morbidity and in the autochthony tendency in the State of São Paulo.

Cryptosporidium sp. in children suffering from acute diarrhea at Uberlândia City, State of Minas Gerais, Brazil

This study's objective was to search for Cryptosporidium sp. in diarrheic feces from children aged zero to 12 years and cared for at medical units within Universidade Federal de Uberlândia or at a private practice in Uberlândia, State of Minas Gerais, Brazil, from September 1992 to August 1993. Three fecal samples preserved in 10% formalin, were collected from 94 children. Oocyst concentration was performed through Ritchie's (modified) method and staining of fecal smears for each sample (total of 1128 slides) was done by the "Safranin/Methylene Blue" and the "Kinyoun (modified)" techniques. The Hoffmann, Pons & Janer method was also employed to look for other enteroparasites. From 94 children, 4.26% excreted fecal Cryptosporidium oocysts. The infection seemed to vary according to age: 5.08% of patients aged zero to two years old; 33.33% of those aging eight to ten years (P>0.05). Cryptosporidium appeared in November, December and March, during the rainy season. 20.21% of the children harbored at least one enteroparasite different from Cryptosporidium, mainly Giardia intestinalis (12.77%). From Cryptosporidium infected patients, two had only this kind, another harbored Giardia intestinalis; the last one hosted Strongyloides stercoralis.

Abdominal Angiostrongylosis in Southern Brazil - Prevalence and Parasitic Burden in Mollusc Intermediate Hosts from Eighteen Endemic Foci

Angiostrongylus costaricensis is a parasitic nematode of rodents and molluscs are the intermediate hosts. Nocturnal collection of molluscs and search for infective third stage larvae of A. costaricensis was carried out in 18 endemic foci identified by the notification of a confirmed diagnosis in human biopsies or surgical specimens. Molluscs were digested in acidic solution and isolation of larvae eventually present was done in a Baermann funnel. Larvae identified by the presence of a delicate groove in the tail were counted to assess the individual parasitic burden. Four species were found infected, with ranges of prevalence in parenthesis: Phyllocaulis variegatus (7% to 33.3%); Bradybaena similaris (11.7% to 24.1%); Belocaulus angustipes (8.3% ) and Phyllocaulis soleiformis (3.3% to 14.2%). Parasitic burden varied from 1 to 75 with P. variegatus, 1 to 98 with B. similaris, 1 to 13 with B. angustipes and 1 larvae in each of two specimens of P. soleiformis. P. variegatus was present in all sites and was found infected with the highest prevalence figures and the highest individual parasitic burdens. These data stress the importance of veronicellid slugs as intermediate hosts for A. costaricensis in the endemic areas in Rio Grande do Sul, Brazil