**This thesis is available at the library of the Instituto de Medicina Tropical de São Paulo.
PREVALENCE OF INTESTINAL PARASITIC INFECTIONS IN PATIENTS WITH ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)
The intestinal parasitoses are spread throughout all countries, registrating high prevalence levels.
When we talk about the relation of parasitoses to aids, it is possible to notice clinical disturbances related to the gastrointestinal tract, manifested through episodes of diarrhea.
This research had, as aim, evaluating the prevalence of the intestinal parasitoses in adult patients with aids, studying the laboratorial and clinical correlation to the different parasitosis investigated and studying the epidemiological correlation (related risk factors) to the different parasitoses.
Two hundred patients with aids interned at the Instituto de Infectologia Emílio Ribas and Hospital São Paulo (DIPA), from September 1996 until April 1997, were rolled up. It was made only one levy of stool's sample, using a sollution of formol conservant at 10%. All the patients presented a level of T4 helper cells less than 200/mm³. Coproscopical methods were conducted (HOFFMAN, PONS and JANER; FAUST and cols.; RUGAI, MATTOS and BRISOLA) and special techniques of coloration (KINYOUN and Auramina Rodamina).
These patients were aged between 20 and 67, with a median of 34. The patients' predominant risk behaviour in our study was related to sexual activity (78%).
The score of the T4 helper cells achieved an average of 97.75 ± 58.90 in those with negative results in stools' exam and an average of 76.65 ± 65.50 with the finding of the vermin in feces.
From 200 patients, 60% (120) did not present any parasite at the protoparasitological exam and 40% (80) had at least one parasite lodged in the gastrointestinal tract.
The global prevalence of parasites with AIDS, in our study, was of: Giardia lamblia (16%), Entamoeba coli (13%), Cryptosporidium parvum (7%), Endolimax nana (3.50%), Ascaris lumbricoides (3.50%), Strongyloides stercoralis (2.50%), Isospora belli (2.00%) and Blastocystis hominis (0.50%).
Analyzing patients with diarrhea and the absence of it, we observed significance in relation to criptosporidiosis (p<0.0001), giardiasis (p=0.0368) and isosporiasis (p=0.0363) and marginal significance in relation to strongiloidiasis (p=0.0764).
About risk behaviour and the presence of parasite in stool, there was not any significant difference in our clinical investigation.
On the account of all these data, additional studies should happen in many places of our country, with the purpose of verifying the endemicity of each parasite in a determined geographic area.
SEROLOGICAL PROFILE OF POPULATIONS EXPOSED TO DIFFERENT MALARIA EPIDEMIOLOGICAL SITUATIONS, IN BRASIL.
In seroepidemiological studies, the IgG anti-P.falciparum erythrocytic forms antibodies survey has contributed to the knowledge of areas with current or past malaria occurrence.
The reliability of the results obtained in serologic tests depends on the quality of the utilized antigen and on strict test standardization.
Initially in this work, we standardized the steps of obtaining antigen components of P. falciparum, from the cultivation of plasmodia to the antigen extract, and the study of technical variables for storage at different time, temperature, detergent interference and the action of protease inhibitors. With the definition of the antigen, we standardized ELISA and Western blotting tests to the anti-plasmodial IgG and IgM antibodies surveys in 1270 sera samples, collected from the population living under different endemic areas of Brazil (Pará and Mato Grosso). We also studied the composition of IgG subclass antibodies (IgG1, IgG2, IgG3) and the avidity of IgG antibodies. The partial results obtained showed positive correlation with level of endemicity and individual exposure, being higher in the individuals with patent or recent parasitemia. The avidity index of IgG antibodies, determined by ELISA, increased with the age and in people with lifelong residence in the endemic areas. In the study of antibody response by Western Blotting, antigenic fractions of P-falciparum were found which were related to IgG antibodies avidity in sera from adults highly exposed to malaria and from individuals with primary infection. A little difference was observed in relation to the investigated IgG subclass antibodies.
HEPATITIS C VIRUS GENOTYPES: EPIDEMIOLOGICAL, CLINICAL, SEROLOGICAL AND THERAPEUTIC RESPONSE PARAMETERS
The recent cloning of the hepatitis C virus (HCV) and the fast developing of serological and molecular techniques revealed a high prevalence of this agent worldwide and a complex infection pattern. HCV is considerably heterogeneous and has been classified in six major genotypes and several (sub)types. The aim of this work was to determine the prevalence of the HCV genotypes and their association with serological, clinical and epidemiological features and influence on response to interferon alpha (IFN-a) therapy in Brazilian patients. Two populations were studied: 140 blood donors (group I), of whom the influence of HCV genotypes and serological response were analyzed, and 130 patients with a chronic HCV infection (group II) whose relationship between viral genotype and clinical, epidemiological and response to IFN-a therapy was analyzed. All samples were tested by ELISA-3, Immunoblot (IB) and nested reverse transcriptase-polymerase chain reaction (RT-PCR). HCV genotype was determined for all PCR-positive subjects using Line Probe Assay (LiPA). One hundred and thirteen out of 130 patients were treated with 3 million units of IFN-a, 3 times a week for 12 months. The response to therapy was evaluated by determination of the ALT level and HCV-RNA, by PCR, at the end of the treatment and after 6 months of follow up. The 1b, 3a and 1a genotypes were the most prevalent in both populations. A clear association was observed between HCV-RNA viremia in samples of group I and index values (O.D. sample/ O.D. cut-off) of the screening ELISA, as well as, with the number of reactive proteins in the IB test. Three samples of group I, found to be negative by ELISA and IB, were positive by PCR; all of them were of genotype 3. Donors infected with HCV genotypes 1 and 3 showed the highest serological reactivity to the core and NS3 antigens. Therefore, most of the donors infected with genotype 3 had reduced antibody reactivity to the non structural antigens of the IB. No significant relationship was found between sex, age, mode of transmission, presence or absence of cirrhosis or time of infection and HCV genotypes in patients with chronic hepatitis C infection. Twenty out of 113 patients (18%) showed a sustained response (SR) to IFN-a. In conclusion, the only baseline feature associated with treatment response was HCV genotype, with a significantly higher SR in genotype 2 (40%) and lower in (sub)type 1b (13%). These findings indicate that the different HCV genotypes have some influence on the serological diagnosis of HCV infection, and on the susceptibility toIFN-a treatment in our population.
Publication Dates
-
Publication in this collection
19 Jan 1999 -
Date of issue
May 1998
