Santo Inácio revisited: protozoan diseases in an isolated village in northeastern Brazil after twenty years.

The northeastern highlands of Brazil are endemic for several tropical diseases, especially American trypanosomiasis (Chagas' disease) and schistosomiasis. Twenty years ago, we measured the seroprevalence of protozoan diseases in Santo Inácio, a village of approximately 1,000 inhabitants located 1,000 m above sea level. We detected small numbers of sera with antibodies against Trypanosoma cruzi and Toxoplasma gondii, and the area had a low prevalence both of American trypanosomiasis (3.54%) and toxoplasmosis (27.43%) compared with nearby Brazilian areas. This was attributed to a specific triatomine vector and local housing conditions. Twenty years later, we again determined the prevalences of both diseases and compared these results with those from Iraquara, a larger town with the same ethnic and social background but with a higher prevalence of rural activities. The incidence of Chagas' disease in San Inácio showed the same low level, i.e., 3.78% (5 of 132) with only adult males affected in contrast with Iraquara, which had an incidence of 34.5%, but a low prevalence of only one of 22 among children up to 14 years of age. Santo Inácio maintained a low (25.8%) seroprevalence for toxoplasmosis. Housewives presented a higher incidence of toxoplasmosis during both periods, probably due to related risk factors. Cats were found less frequently in Santo Inácio than in Iraquara, which showed an incidence of 65.5% seropositivity for Toxoplasma gondii. These results suggest that the environmental conditions of Santo Inácio were preserved after 20 years, with a low incidence of these selected protozoan diseases.

Dot-ELISA for the detection of IgM and IgG antibodies to Schistosoma mansoni worm and egg antigens, associated with egg excretion by patients.

Human schistosomiasis, caused by Schistosoma mansoni, is highly prevalent in Brazil and usually diagnosed by time consuming stool analysis. Serological tests are of limited use in this disease, mainly for epidemiological studies, showing no discrimination between previous contact with the parasite and active infections. In the present study, we standardized and compared a Dot-ELISA for IgM and IgG antibodies against S. mansoni antigens from eggs and worms with a routine IgG and IgM immunofluorescence assay using similar antigens, in the study of sera from 27 patients who had quantified egg stool excretion. The positivity obtained for IgG Dot-ELISA was 96.3% and 88.9% for IgM Dot-ELISA with worm antigen and 92.6% and 90.9% with egg antigen. The IFI presented similar positivities using worm antigen, 92.6% (IgG) and 96.3% (IgM), and lower results with egg antigen, 77.8%(IgG and IgM). The patients studied were divided into two groups according to their egg excretion, with greater positivity of serological tests in higher egg excreters. When comparing the quantitative egg excretion and the serological titers of the patients, we detected a correlation only with IgM Dot-ELISA, with r = 0.552 (p = 0.0127). These data show that Dot-ELISA can be used for the detection of specific antibodies against S. mansoni in sera from suspected patients or in epidemiological studies and, with further purification of egg antigen and larger samples, IgM Dot-ELISA could be a possible tool for rough estimates of parasite burden in epidemiological studies.

[Evaluation of the therapeutic activity of itraconazole in chronic infections, experimental and human, by Trypanosoma cruzi]. / Avaliação da atividade terapêutica do itraconazol nas infecções crônicas, experimental e humana, pelo Trypanosoma cruzi.

Other authors have demonstrated that itraconazole has antiparasitic activity against Trypanosoma cruzi both in vitro and in animal acute infection. Because of these observations, we decided to evaluate the chronic phase of this protozoal disease, since it is the most important form under a clinical and assistential point of view. We studied an infected mouse model as well as human cases of Chagas' disease. One hundred mg/kg/day by gastric tube, and 100 or 200 mg/day orally were given, respectively, during three months, without showing any beneficial effect, at least with the adopted methods.

[Evaluation of the therapeutic effect of albendazole on experimental and human infections by Hymenolepis nana]. / Avaliação da atividade terapêutica do albendazol sobre infecções experimentale e humana pela Hymenolepis nana.

With the objective of knowing adequately the spectrum of activity of albendazole against intestinal helminthiases, we made observations regarding hymenolepiasis caused by Hymenolepis nana. Two series of investigations were carried out: a) treatment of mice with single doses of either 25 or 50 mg/kg, repeated after ten days, using as controls animals treated with 25 mg/kg of praziquantel or not treated with any antiparasitic drugs; b) treatment of adults and children with 400 mg daily for three consecutive days, repeated after ten days.

[Viability of Trypanosoma cruzi in sugar cane juice]. / Observações sobre a viabilidade do Trypanosoma cruzi no caldo da cana.

In Catolé do Rocha, State of Paraíba, Brasil several people were concomitantly contaminated by Chagas' disease and had the acute form of the infection. Because of this event, the hypothesis that Trypanosoma cruzi might have been transmitted by the digestive route, through the ingestion of accidentally contaminated sugar cane juice, was made. In the present study, we verified that the parasite has remained viable for four hours in the liquid, at room temperature. We have also demonstrated that, after one hour, it was capable of promoting infection in one mouse, by gastric tube administration. These observations enhance the interest on this alternative mechanism of disease transmission.

[Treatment of experimental infection by Strongyloides venezuelensis in rats, with the use of injectable ivermectin and levamisole]. / Tratamento da infecção experimental de ratos por Strongyloides venezuelensis, mediante uso da ivermectina e do levamisol injectáveis.

For the therapy of human strongyloidiasis, are necessary effective drugs to eliminate both larvae and adult worm parasitism, which may also be used by parenteral route, to obviate the particular conditions presented by many patients. A study based on the experimental infection by Strongyloides venezuelensis in rats was done, administering injectable ivermectin or levamisole. Both drugs were shown to be active, when used in single doses of 0.2 to 0.5 mg/kg of ivermectin, or 26 mg/kg for levamisole. Ivermectin was slightly more effective as far as larval stage of the infection is concerned, and the same happened for levamisole for the adult worm stage. Promising perspectives are visualized to improve the therapy of patients with serious disseminated infection by Strongyloides stercoralis.

[The use of sodium azide as a fecal preservative for studying the eggs of Schistosoma mansoni and of other helminths by the Kato-Katz method: a study in an endemic area]. / Emprego da azida sódica, como conservador de fezes, para a pesquisa de ovos de Schistosoma mansoni e de outros helmintos, pelo método de Kato-Katz: estudo em área endêmica.

In two aliquots of 208 samples of stool, tests have been made by the Kato-Katz method, one being made after the use of 0.2mg of sodic azide for 200mg, and the other without the aforesaid conservant. The resulted percentages with or without the conservant were, respectively, for Ancylostomideos: 12.5 and 25.9; for Ascaris lumbricoides: 71.6 and 72.5; for Schistosoma mansoni: 7.6 and 17.7, and for Trichuris trichiura: 86 and 85. The count of the eggs with and without the conservant was, respectively, 264 and 539 for Ancylostomideos, 13186 and 33751 for A. lumbricoides, 55.5 and 63.5 for S. mansoni, and 1345 and 2068 for T. trichiura. The authors did not confirm the advantage of using sodic azide for study in endemic areas. They suggest that the exsiccation of the stool and the low intensity of infections can explain the unfavourable results of the present clinical trial.

[Eventual effect of artemisinine on the experimental infection of mice by Toxoplasma gondii]. / Estudo sobre a eventual ação da artemisinina na infecção experimental de camundongos pelo Toxoplasma gondii.

Because of taxonomic similarities to previous data found in the literature, and with the aim of improving treatment of toxoplasmosis, we considered it of interest to assay artemisinin, an effective anti-malarial agent, for the treatment of experimental infection in mice by Toxoplasma gondii. Different amounts of the anti-parasitic agent were administered, including after previous contact in vitro with toxoplasma and stimulated macrophage production. With the methodology used artemisinin was not effective. Suggestions for further studies are made.

[Aedes albopictus in rural zone of Brazil and its implication in the wild yellow fever transmission]. / Aedes albopictus em área rural do Brasil e implicações na transmissão de febre amarela silvestre.

Larvae and adult forms of Aedes albopictus were found during ecological study of anopheline mosquitos in the rural zone of the state of Mato Grosso do Sul in Brazil. This occurrence was registered, for the first time in Brazil, in an enzoootic area if sylvatic yellow fever virus. This implies a potential risk of the transfer of this virus to an urban area infested with Aedes aegypti.

Atopy and enteroparasites.

UNLABELLED: There are not many studies about the intestinal parasitosis (IP) and atopic asthma (AA) relationship, and these show discordant results, possibly due to different studies design and differences in population selection. On the basis of personal results obtained by an epidemiological inquiry designed to estimate the prevalence of enteroparasitoses in asthmatic children and vice vesa, the aim of this study was to compare the prevalence of IP in AA and in a control group (CG) by a cross sectional study using clinical and laboratorial parameters, applied to 63 children (47 with AA and 16 in CG) aged 6 to 11 years, 37 males and 26 females, Caucasians, with the same socioeconomical conditions, consecutively selected in our Hospital. The results showed: The IP in AA children was 21.3%; the IP in CG was 25%; in the group with AA and IP, 40% of them had symptomology of IP; in the CG with IP, 100% had symptoms. CONCLUSIONS: The IP prevalence in AA was not statistically different from the IP in CG (p > 0.05) More data are needed to clarify the significant differences between the symptomatology rates of IP in asthmatic and non asthmatics; the reduced number of patients with symptoms in AA may reflect modulation of IP in AA and/or different parasite load.

Soluble CD30, dehydroepiandrosterone sulfate and dehydroepiandrosterone in atopic and non atopic children.

Elevated levels of soluble CD30-sCD30 (possibly related to Th2) are seen in atopy and other diseases. Dehydroepiandrosterone (DHEA) may regulate Th1/Th2 balance. The aim was to study the relationship between the levels of sCD30, DHEAS and DHEA in atopic (A) and non atopic (B) children, to assess immune-endocrine interactions. We studied 36 children (8-15 years), 18 (A) monosensitised to Dermatophagoides Pteronyssinus (Dpt.), and 18 (B) with isolate rhinitis (R) or asthma (BA) and R (33.3%) without differences in age and sex. They were all HIV negative and free from any medication. It was determined sCD30, DHEAS and DHEA. There was no statistically significant differences between A and B for the levels of DHEAS, DHEA suggesting that the role of this regulation in Th2 type is not important in patients with allergic disease in this age group. sCD30: A-mean 121.1U/ml; B-mean 53.9U/ml. This difference is statistically significant-p = 0.02. sCD30 in patients only with R showed also significant differences-p = 0.01. These results could reflect the Th2 profile. There is an overlap of the values (for R < 80 U/ml; for BA + R < 140 U/ml). Due to this only values > 80 U/ml for R and > 140 U/ml for BA + R could be considered discriminating for atopy.

Quantitative skin prick tests and specific IgE (CAP System) for D. pteronissynus--correlation of results in a paediatric population.

The CAP System compared with RAST has a greater sensitivity, with the same specificity, as well as an excellent correlation with skin prick tests (SPT), as documented by others. Standardization of SPT is essential for routine and investigational purposes. We used a standardized lancet (DHS), and the methodology of reading the SPT was a computerized digitalized graphics tablet coupled to an IBM-PC AT using CAD software, expressing the result as wheal areas with cut off +/- at 7 mm2. The method is precise and reproducible with a mean coefficient of variation (cv) intratester--T1: 3.1%, T2: 3.5% and a cv intertester: 2.93%. We compare the results of SPT of two different allergen extracts for Dermatophagoides Pteronissynus (DPt) (Bencard; Merck/Allergo-Pharma, standardized in SBU) and correlate them with specific IgE, in 122 patients, 72 males and 50 females, aged 3 to 19 years. The results between the extracts and the results of specific IgE obtained by CAP System with each of the extracts, were correlated. 34 patients were considered to be non atopic. 88 patients showed at least one positive result with one test, being those used to correlate the positive results.... The results showed good correlations for quantitative SPT between Bencard and Merck/Allergo-Pharma, as well as for the capacity of eliciting positive results. When SPT were compared to specific IgE as +/- and as quantitative results, there were good correlation for Bencard/CAP and Merck/CAP. The results obtained suggest that CAP can be used to validate allergen extracts of DPt and that studies with other extract are advisable.

ALATOP:sensitivity, specificity and predictive value of a new "in vitro" screening test of atopy.

UNLABELLED: The limitations of total IgE for the screening of atopy, gave rise to in vitro multispecific IgE tests to common allergens. These should have an increased sensitivity and specificity when compared to total IgE. Previous data showed the interest of such tests in screening procedures. ALATOP is a new in vitro multispecific IgE test including common aero and food allergens, in liquid phase, for paediatric and adult population. The result is expressed only in positive/negative. The aim of the study was to determine the sensitivity, specificity, positive and negative predictive value and test efficiency, by comparing the results obtained in 266 paediatric patients (selected in our Unit based on a good correlation between clinical history and skin prick tests--SPT), between ALATOP and SPT. RESULTS: 1) Sensitivity: 89.57%; 2) Specificity: 98.06%; 3) Positive predictive value: 98.65%; 4) Negative predictive value: 85.59%; 5) Efficiency of the test: 92.86%; 6) Reproducibility of the test--average: 5.63%. Based on this results and when they are compared to single specific IgE determinations, that are assumed to be about 80% of the sensitivity of SPT, ALATOP showed excellent results, allowing its use in the screening of atopic disease.

ALATOP-RIA in the screening of atopy in a non Caucasian population.

UNLABELLED: ALATOP is an "in vitro" radioimmunoassay screening test for atopy, previously validated in a caucasian population. The aim of the study was to assess the usefulness of a screening test of atopy in a non caucasian population. We select a non caucasian population (n = 208), from hospital immunoallergy consultations, Cape Verde Republic (Africa). It was determined the sensitivity, specificity and predictive values comparing with skin prick tests (SPT) results for the 208 patients, and with clinical data (Clin) in 115 patients. It was also determined the levels of total IgE, done by IRMA. RESULTS: Using different corrections factors, 0.85 gives the best results: ALATOP/SPT-Sensitivity-88.5% +/- 4.34; Specificity-73.8% +/- 8.41; Positive predictive value-66.9%; Negative predictive value-91.4%; Efficiency of the test-79.3%. ALATOP/CLIN-Sensitivity-95.2% +/- 3.89; Specificity-71.2% +/- 12.07; Positive predictive value-65.6%; Negative predictive value-96.2%; Efficiency of the test-80.0%. The mean values of total IgE were-406 IU/ml. CONCLUSIONS: The mean value of total IgE was significantly increased even in the ALATOP-/SPT-not saw in caucasian populations. The use of a different correction factor (0.85) for ALATOP, optimize the test, showing a good negative predictive value, but raises the question of adapted compositions of screening tests for different populations.

Structural parameters, molecular properties, and biological evaluation of some terpenes targeting schistosoma mansoni parasite

The use of natural products has a long tradition in medicine, and they have proven to be an important source of lead compounds in the development of new drugs. Among the natural compounds, terpenoids present broad-spectrum activity against infective agents such as viruses, bacteria, fungi, protozoan and helminth parasites. In this study, we report a biological screening of 38 chemically characterized terpenes from different classes, which have a hydroxyl group connected by hydrophobic chain or an acceptor site, against the blood fluke Schistosoma mansoni, the parasite responsible for schistosomiasis mansoni. In vitro bioassays revealed that 3,7-dimethyl-1-octanol (dihydrocitronellol) (10) was the most active terpene (IC50 values of 13­52 µM) and, thus, we investigated its antischistosomal activity in greater detail. Confocal laser scanning microscopy revealed that compound 10 induced severe tegumental damage in adult schistosomes and a correlation between viability and tegumental changes was observed. Furthermore, we compared all the inactive compounds with dihydrocitronellol structurally by using shape and charge modeling. Lipophilicity (miLogP) and other molecular properties (e.g. molecular polar surface area, molecular electrostatic potential) were also calculated. From the 38 terpenes studied, compound 10 is the one with the greatest flexibility, with a sufficient apolar region by which it may interact in a hydrophobic active site. In conclusion, the integration of biological and chemical analysis indicates the potential of the terpene dihydrocitronellol as an antiparasitic agent.

Comparative study of the accuracy of different technique for the laboratory diagnosis of schistosomiasis mansoni in areas of low endemicity in Barra Mansa City, Rio de Janeiro State, Brazil

Schistosomiasis constitutes a major public health problem, with an estimated 200 million people infected worldwide. Many areas of Brazil show low endemicity of schistosomiasis, and the current standard parasitological techniques are not sufficiently sensitive to detect the low-level helminth infections common in areas of low endemicity (ALEs). This study compared the Kato-Katz (KK); Hoffman, Pons, and Janer (HH); enzyme-linked immunosorbent assay- (ELISA-) IgG and ELISA-IgM; indirect immunofluorescence technique (IFT-IgM); and qPCR techniques for schistosomiasis detection in serum and fecal samples, using the circumoval precipitin test (COPT) as reference. An epidemiological survey was conducted in a randomized sample of residents from five neighborhoods of Barra Mansa, RJ, with 610 fecal and 612 serum samples. ELISA-IgM (21.4%) showed the highest positivity and HH and KK techniques were the least sensitive (0.8%). All techniques except qPCR-serum showed high accuracy (82­95.5%), differed significantly from COPT in positivity , and showed poor agreement with COPT. Medium agreement was seen with ELISA-IgG (Kappa = 0.377) and IFA (Kappa = 0.347). Parasitological techniques showed much lower positivity rates than those by other techniques. We suggest the possibility of using a combination of laboratory tools for the diagnosis of schistosomiasis in ALEs.