PCR in the First Oropharynx Aspirate of the Newborn: A Possible Source for Identification of Congenital Infection Agents

We present a case of prenatal diagnosis of congenital rubella. After birth, in addition to traditional serologic and clinical examinations to confirm the infection, we could identify the virus in the "first fluid aspirated from the oropharynx of the newborn", using polimerase chain reaction (PCR). We propose that this first oropharynx fluid (collected routinely immediately after birth) could be used as a source for identification of various congenital infection agents, which may not always be easily identified by current methods

QUESTIONNAIRES IN THE SCREENING FOR Schistosoma mansoni INFECTION: A STUDY OF SOCIO DEMOGRAPHIC AND WATER CONTACT VARIABLES IN FOUR COMMUNITIES IN BRAZIL

The use of questionnaires has been recommended for identifying, at a lower cost, individuals at risk for schistosomiasis. In this study, validity of information obtained by questionnaire in the screening for Schistosoma mansoni infection was assessed in four communities in the State of Minas Gerais, Brazil. Explanatory variables were water contact activities, sociodemographic characteristics and previous treatment for schistosomiasis. From 677, 1474, 766 and 3290 individuals eligible for stool examination in the communities, 89 to 97% participated in the study. The estimated probability of individuals to be infected, if they have all characteristics identified as independently associated with S.mansoni infection, varied from 15% in Canabrava, to 42% in Belo Horizonte, 48% in Comercinho and 80% in São José do Acácio. Our results do not support the hypothesis that a same questionnaire on risk factors could be used in screening for S.mansoni infection in different communities.

FETO-PLACENTARY PATHOLOGY IN HUMAN PARVOVIRUS B19 INFECTION

In view of the scarce references concerning the histological data in congenital parvovirus human B19 infection, we intend to provide a description of the pathological features observed in six autopsies.The virus was detected by DNA hybridization (ISH-DBH),PCR and electronmicroscopy (EM) in paraffin-embedded feto-placentary tissues.These cases constitute a subset from 86 Non Immunologic Hydrops Fetalis (NIHF) cases, in which a systemic complex of inflammatory/degenerative lesions of unknown etiology was visualized by optical microscopy. In one case a syphilitic process was detected, typefying a double infection. All fetuses showed a similar pathology - hydrops, hepato-splenomegaly, lung hypoplasia and erythroblastemia, the specific histological feature being the presence of intranuclear inclusions in the erythroid progenitors, in the erythropoietic visceral tissue and in blood marrow. Complex cardiopathy allied to abnormal lung lobulation and polisplenia were observed once; in 2 cases endocardial fibroelastosis was diagnosed. The pulmonary lesions were represented by dysmaturity allied to interstitial mononuclear infiltration. The hepatic consisted of cholestasis, portal fibrosis, canalicular proliferation, hemossiderosis, focal necroses and giant cell transformation. The central nervous system lesions were predominantly anoxic although the autolysis impaired a correct diagnosis.

SIMULTANEOUS INFECTION WITH DENGUE 1 AND 2 IN A BRAZILIAN PATIENT

Dengue outbreaks have occurred in several Brazilian States since 1986 involving serotypes 1 (DEN-1) and 2 (DEN-2). In view of the few cases of double infection documented in the literature, we report here a case of simultaneous infection with DEN-1 and DEN-2 in a patient residing in the municipality of Miranda, State of Mato Grosso do Sul, Western region of Brazil. DEN-1 was introduced in this State in 1989 and DEN-2 in 1996, both of them circulating in some municipalities. This double infection was identified by virus isolation and by indirect immunofluorescence using monoclonal antibodies and confirmed by the polymerase chain reaction (PCR). This is the first documented case of simultaneous infection with serotypes DEN-1 and DEN-2 in Brazil.

HEPATITIS B VIRUS INFECTION PROFILE IN CENTRAL BRAZILIAN HEMODIALYSIS POPULATION

Hepatitis B has proved to be a major health hazard in hemodialysis patients. In order to investigate the hepatitis B virus (HBV) infection profile in the hemodialysis population of Goiânia city - Central Brazil, all dialysis patients (N=282) were studied. The prevalence of any HBV marker (HBsAg, anti-HBs, and anti-HBc) was 56.7% (95% CI: 51.1-62.7), ranging from 33.3% to 77.7% depending on dialysis unit. HBV-DNA was detected in 67.6% and 88.2% of the HBsAg-positive serum samples, in 91.3% and 100% of the HBsAg/HBeAg-positive samples, and in 18.2% and 63.6% of the HBsAg/anti-HBe-reactive sera by hybridization and PCR, respectively. The length of time on hemodialysis was significantly associated with HBV seropositivity. Only 10% of the patients reported received hepatitis B vaccination. The findings of a high HBV infection prevalence in this population and the increased risk for HBV infection on long-term hemodialysis suggest the environmental transmission, emphasizing the urgent need to evaluate strategies of control and prevention followed in these units.

SIMPLIFIED DIAGNOSIS OF MALARIA INFECTION: GFM/PCR/ELISA A SIMPLIFIED NUCLEIC ACID AMPLIFICATION TECHNIQUE BY PCR/ELISA

We report an adaptation of a technique for the blood sample collection (GFM) as well as for the extraction and amplification of Plasmodium DNA for the diagnosis of malaria infection by the PCR/ELISA. The method of blood sample collection requires less expertise and saves both time and money, thus reducing the cost by more than half. The material is also suitable for genetic analysis in either fresh or stored specimens prepared by this method.

INFLUENCE OF DIETARY PROTEIN CONTENT ON Trypanosoma cruzi INFECTION IN GERMFREE AND CONVENTIONAL MICE

Germfree (GF) and conventional (CV) mice were fed on diets containing 4.4, 13.2 or 26.4% of protein (weight/weight). CV mice fed on low protein diet did not gain weight during four weeks, whereas the protein deficient diet did not affect the growth of GF mice. After four weeks on these diets, the mice were inoculated with 5x103 trypomastigotes of Trypanosoma cruzi. The protein deficiency affected less the GF than the CV mice, according to the following parameters: weight gain, hemoglobin, plasma protein and albumin levels and water and protein contents of the carcass. Infection with T. cruzi produced a significant decrease in hemoglobin levels, red blood cell count, and water and protein contents in the carcass. This decrease was more pronounced in the GF mice. Histopathologically, there was no difference between the treatments in animals with the same microbiological status (GF or CV). However, the disease was more severe in the GF than in the CV mice.

Efficiency of indirect immunofluorescence assay as a confirmatory test for the diagnosis of human retrovirus infection (HIV-1 and HTLV-I/II) in different at risk populations

We compared the indirect immunofluorescence assay (IFA) with Western blot (Wb) as a confirmatory method to detect antibodies anti retrovirus (HIV-1 and HTLV-I/II). Positive and negative HIV-1 and HTLV-I/II serum samples from different risk populations were studied. Sensitivity, specificity, positive, negative predictive and kappa index values were assayed, to assess the IFA efficiency versus Wb. The following cell lines were used as a source of viral antigens: H9 ( HTLV-III b); MT-2 and MT-4 (persistently infected with HTLV-I) and MO-T (persistently infected with HTLV-II). Sensitivity and specificity rates for HIV-1 were 96.80% and 98.60% respectively, while predictive positive and negative values were 99.50% and 92.00% respectively. No differences were found in HIV IFA performance between the various populations studied. As for IFA HTLV system, the sensitivity and specificity values were 97.91% and 100% respectively with positive and negative predictive values of 100% and 97.92%. Moreover, the sensitivity of the IFA for HTLV-I/II proved to be higher when the samples were tested simultaneously against both antigens (HTLV-I-MT-2 and HTLV-II-MO-T). The overall IFA efficiency for HIV-1 and HTLV-I/II-MT-2 antibody detection probed to be very satisfactory with an excellent correlation with Wb (Kappa indexes 0.93 and 0.98 respectively). These results confirmed that the IFA is a sensitive and specific alternative method for the confirmatory diagnosis of HIV-1 and HTLV-I/II infection in populations at different levels of risk to acquire the infection and suggest that IFA could be included in the serologic diagnostic algorithm.

Characterization of rotavirus P genotypes circulating among paediatric inpatients in Northern Brazil

Between November 1992 and August 1993, twenty-eight rotavirus-positive stool samples obtained from paediatric inpatients in Belém, Brazil, aged less than four years, were tested by RT-PCR to determine the P genotype specificities. With the exception of 7 non-diarrhoeic children, all patients were either diarrhoeic at admission or developed diarrhoea while in hospital. Rotavirus strains with the gene 4 alleles corresponding to P1B[4] and P1A[8] types (both of which bearing G2 specificity) predominated, accounting for 78.6% of the strains. While only one P2A[6] type strain - with (mixed) G1 and 4 type specificities - was detected, the gene 4 allele could not be identified in 4 (14.3%) of the strains. Most (81%) of the specimens were obtained from children during their first 18 months of life. Rotavirus strains bearing single P1B[4] type-specificity were identified in both diarrhoeic (either nosocomial, 28.6% or community-acquired diarrhoea, 28.6%) and non-diarrhoeic (42.8%) children. P1A[8] gene 4 allele, on the other hand, was detected only among diarrhoeic children, at rates of 57.1% and 42.9% for nosocomial- and- community acquired diarrhoea, respectively. Mixed P1A[8],1B[4] type infection was identified in only one case of community-acquired diarrhoea.

Toxoplasma gondii infection in Brazilian domestic outpatient cats

The occurrence of Toxoplasma antibodies in domestic outpatient cats in the city of São Paulo was evaluated using the indirect immunofluorescence assay. A total of 248 blood samples obtained from male and female cats seen at the Veterinary Teaching Hospital at the University of São Paulo between February 1996 and January 1997 were tested. Of these, 17.7% were positive, with a 64 titer being detected in most animals. The frequence of Toxoplasma antibodies was significantly higher in older cats, those fed raw meat and those with free access to the outdoor environment. There was no significant difference in reactivity between males and females. We conclude that diet and free access to the outdoor environment were equally important as predisposing factors to the risk of Toxoplasma infection.

Prevalence of Trypanosoma cruzi and Leishmania chagasi infection and risk factors in a Colombian indigenous population

This study was carried out in order to obtain base-line data concerning the epidemiology of American Visceral Leishmaniasis and Chagas’ Disease in an indigenous population with whom the government is starting a dwelling improvement programme. Information was collected from 242 dwellings (1,440 people), by means of house to house interviews about socio-economic and environmental factors associated with Leishmania chagasi and Trypanosoma cruzi transmission risk. A leishmanin skin test was applied to 385 people and 454 blood samples were collected on filter paper in order to detect L. chagasi antibodies by ELISA and IFAT and T. cruzi antibodies by ELISA. T. cruzi seroprevalence was 8.7% by ELISA, L. chagasi was 4.6% and 5.1% by IFAT and ELISA, respectively. ELISA sensitivity and specificity for L. chagasi antibodies were 57% and 97.5% respectively, as compared to the IFAT. Leishmanin skin test positivity was 19%. L. chagasi infection prevalence, being defined as a positive result in the three-immunodiagnostic tests, was 17.1%. Additionally, 2.7% of the population studied was positive to both L. chagasi and T. cruzi, showing a possible cross-reaction. L. chagasi and T. cruzi seropositivity increased with age, while no association with gender was observed. Age (p<0.007), number of inhabitants (p<0.05), floor material (p<0.03) and recognition of vector (p<0.01) were associated with T. cruzi infection, whilst age ( p<0.007) and dwelling improvement (p<0.02) were associated with L. chagasi infection. It is necessary to evaluate the long-term impact of the dwelling improvement programme on these parasitic infections in this community.

Clinical and laboratory findings of disseminated Mycobacterium avium complex infection (DMAC) in a pair matched case-control study

A pair matched case/control study was conducted from January 1991 to 30 June 1992 in order to define clinical and laboratory findings associated with DMAC infection in AIDS patients. Since DMAC infection is usually associated with advanced immunodeficiency, and therefore also with other opportunistic illnesses, in addition to the number of CD4+ lymphocytes, cases and controls were matched using the following criteria: date of AIDS diagnosis and antiretroviral therapy, number and severity of associated opportunistic infections and, whenever possible, type of Pneumocystis carinii prophylaxis, age and gender, in this order of relevance. Cases (defined as patients presenting at least one positive culture for MAC at a normally sterile site) and controls presented CD4+ lymphocyte counts below 50 cel/mm3. A significantly higher prevalence of general, digestive and respiratory signs, increased LDH levels, low hemoglobin levels and CD4+ cell counts were recorded for cases when compared to controls. Increases in gGT and alkaline phosphatase levels seen in cases were also recorded for controls. In conclusion, the strategy we used for selecting controls allowed us to detect laboratory findings associated to DMAC infection not found in other advanced immunossupressed AIDS patients without DMAC.

Genetic variation between susceptible and non-susceptible snails to Schistosoma infection using random amplified polymorphic DNA analysis (RAPDs)

Susceptibility of snails to infection by certain trematodes and their suitability as hosts for continued development has been a bewildering problem in host-parasite relationships. The present work emphasizes our interest in snail genetics to determine what genes or gene products are specifically responsible for susceptibility of snails to infection. High molecular weight DNA was extracted from both susceptible and non-susceptible snails within the same species Biomphalaria tenagophila. RAPD was undertaken to distinguish between the two types of snails. Random primers (10 mers) were used to amplify the extracted DNA by the polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis (PAGE) and silver staining. The results suggest that RAPD represents an efficient means of genome comparison, since many molecular markers were detected as genetic variations between susceptible and non-susceptible snails.