Laboratory acquired infection by the virus SP H 114202 (Arenavirus: Arenaviridae): clinical and laboratory findings

Here in is described the clinical and laboratorial findings of a laboratory-acquired infection caused by the virus SP H 114202 (Arenavirus, family Arenaviridae) a recently discovered agent responsible for a viral hemorrhagic fever. The patient was sick for 13 days. The disease had an abrupt onset characterized by high fever (39ºC.), headache, chills and myalgias for 8 days. In addition, on the 3rd day, the patient developed nauseas and vomiting, and in the 10th, epigastralgia, diarrheia and gengivorrhagia. Leucopenia was seen within the 1 st week of onset, with counts as low as 2,500 white cells per mm³. Counts performed after the 23th day of the onset were within normal limits. With the exception of moderate lymphocitosis, no changes were observed in differential counts. An increase in the liter of antibodies by complement fixation, neutralization and ELISA (IgM) was detected. Suckling mice and baby hamsters were inoculated intracerebrally with 0.02 ml of blood samples collected in the 2nd and 7th days of disease. Attempts to isolate the virus were also made in Vero cells. No virus was isolated. This virus was isolated before in a single occasion in São Paulo State, in 1990, from the blood of a patient with hemorrhagic fever with a fatal outcome. The manipulation of the virus under study, must be done carefully, since the transmission can occur through aerosols.

Murine virus contaminant of Trypanosoma cruzi experimental infection

The possibility that some virus contaminants could be altering host response to Trypanosoma cruzi experimental infection was investigated. Data obtained showed that CBA/J mice infected with stocks of parasite maintained in mice (Y1UEC) presented higher level of parasitemia and shorter survival times than those infected with a stock (Y1TC) which was also maintained in mice but had been previously passaged in cell culture. Mouse antibody production tests, performed with the filtered plasma of mice infected with Y1UEC, indicated the presence of mouse hepatitis virus (MHV) while no virus was detected when testing the plasma of Y1TC infected mice. Filtered plasma of Y1EUC infected mice was shown to contain a factor able to enhance the level of parasitemia and to reduce the mean survival time of mice challenged with 10(5) Y1TC. This factor, that could be serially passaged to naïve mice was shown to be a coronavirus by neutralization tests.

Serological findings during a measles outbreak occurring in a population with vaccine coverage

From March 1991 to April 1992, serum samples for IgM detection were collected from 112 clinical measles cases reported to the Health Department of Niterói, State of Rio de Janeiro. The positivity exceeded 90% for specimens collected from the 5th to the 29th day after the onset of the disease. After day 30 a decline in IgM detection was observed, although positivity has been detected up to 90 days after the onset of the symptoms. Forty-four patients (48.9%) with an IgM response had a history of prior measles vaccination. In 5 of the 22 measles-IgM negative cases the infection was due to other agents (rubella: 4 cases, dengue: 1 case). These results show that sensitivity of the test employed for confirming suspected measles cases is high, even in vaccinated patients.

Risk factors and prevalence of antibodies against hepatitis A virus (HAV) in children from day-care centers, in Goiania, Brazil

A seroepidemiologic survey about hepatitis A virus (HAV) infection was carried out in a group comprising 310 children, ranging in age from 3 months to 9 years, from day-care centers, in Goiania, a middle sized city in the central region of Brazil. The biomarkers employed in the investigation of previous infection include total IgG and IgM anti-HAV antibodies, and for the detection of more recent infection, IgM anti-HAV antibodies were analyzed. The study was performed in 1991 and 1992. According to the results, 69.7% of the children presented total IgG/IgM anti-HAV antibodies, with 60% of the group in the age range of 1 to 3 years. Among 10 day-care centers analyzed, the prevalence of the biomarker IgM anti-HAV was 3.2%, with an uniform distribution of the cases in the group of children ranging in age from 1 to 4 years. Multi-variate analysis was performed to investigate the sociodemographic factors that could influence the results. It was verified that the risk for the infection increased with the length of the attendance in the day-care centers, i.e., the risk for children with attendance of one year or more was 4.7 times higher, when compared with children with one month attendance (CI 95% 2.3-9.9). According to the results, hepatitis A is an endemic infection in day-care centers in the study area. The length of attendance in the day-care settings was demonstrated to be a risk factor for the HAV infection. Such findings suggest that if hepatits A vaccination becomes available as a routine policy in our region, the target group should be children under one year. Moreover, those children should receive the vaccine before they start to attend the day-care centers.

Hepatitis G virus / GB virus C in Brazil. Preliminary report

Hepatitis G virus/ GB virus C is a novel flavivirus recently detected in hepatitis non A-E cases. In this study, the presence of this virus in chronic non-B, non-C hepatitis patients was evaluated using GBV-C specific PCR and this virus was detected in one out of thirteen patients. This patient has presented a severe liver failure, has lived for a long time in the Western Amazon basin and no other cause for this clinical picture was reported. The impact of the discovery of this new agent is still under evaluation throughout the world. The study of the prevalence of this virus among chronic hepatitis patients and healthy individuals (as blood donors) will furnish subside to evaluate its real pathogenicity.

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.

Measles antibody prevalence after mass immunization campaign in Niterói, State of Rio de Janeiro, Brazil

Three months after a mass vaccination campaign (coverage: 100%) against measles a random seroepidemiological survey was carried out in students aged 1 to 19 years old in the Municipality of Niterói, State of Rio de Janeiro. Blood samples were tested for measles antibodies by enzyme immunosorbent assay (EIA) and negative cases were tested again using hemagglutination inhibition (HI) and plaque reduction neutralization (PRN). Of the 798 samples tested by EIA, 718 (90.2%) were positive for measles antibodies. PRN test was more sensitive than EIA and HI in detecting measles specific antibodies. The total antibody prevalence increased from 90.2% to 93.2% when HI was employed in EIA negative specimens and to 98.9% when PRN was used. After the mass vaccination campaign a marked decrease in measles incidence was observed in the municipality studied, showing the effectiveness of the strategy used for measles control in developing countries.

GB virus C/Hepatitis G virus and other putative hepatitis non A-E viruses

The identification of the major agents causing human hepatitis (Hepatitis A, B, C, D and E Viruses) was achieved during the last 30 years. These viruses are responsible for the vast majority of human viral hepatitis cases, but there are still some cases epidemiologically related to infectious agents without any evidence of infection with known virus, designated as hepatitis non A - E. Those cases are considered to be associated with at least three different viruses: 1 - Hepatitis B Virus mutants expressing its surface antigen (HBsAg) with altered epitopes or in low quantities; 2 - Another virus probably associated with enteral transmitted non A-E hepatitis, called Hepatitis F Virus. Still more studies are necessary to better characterize this agent; 3 - Hepatitis G Virus or GB virus C, recently identified throughout the world (including Brazil) as a Flavivirus responsible for about 10% of parenteral transmitted hepatitis non A-E. Probably still other unknown viruses are responsible for human hepatitis cases without evidence of infection by any of these viruses, that could be called as non A-G hepatitis.

Detection and identification of dengue virus isolates from Brazil by a simplified reverse transcription - polymerase chain reaction (RT-PCR) method

We show here a simplified RT-PCR for identification of dengue virus types 1 and 2. Five dengue virus strains, isolated from Brazilian patients, and yellow fever vaccine 17DD as a negative control, were used in this study. C6/36 cells were infected and supernatants were collected after 7 days. The RT-PCR, done in a single reaction vessel, was carried out following a 1/10 dilution of virus in distilled water or in a detergent mixture containing Nonidet P40. The 50 µl assay reaction mixture included 50 pmol of specific primers amplifying a 482 base pair sequence for dengue type 1 and 210 base pair sequence for dengue type 2. In other assays, we used dengue virus consensus primers having maximum sequence similarity to the four serotypes, amplifying a 511 base pair sequence. The reaction mixture also contained 0.1 mM of the four deoxynucleoside triphosphates, 7.5 U of reverse transcriptase, 1U of thermostable Taq DNA polymerase. The mixture was incubated for 5 minutes at 37ºC for reverse transcription followed by 30 cycles of two-step PCR amplification (92ºC for 60 seconds, 53ºC for 60 seconds) with slow temperature increment. The PCR products were subjected to 1.7% agarose gel electrophoresis and visualized by UV light after staining with ethidium bromide solution. Low virus titer around 10 3, 6 TCID50/ml was detected by RT-PCR for dengue type 1. Specific DNA amplification was observed with all the Brazilian dengue strains by using dengue virus consensus primers. As compared to other RT-PCRs, this assay is less laborious, done in a shorter time, and has reduced risk of contamination

Dynamic and interaction of cytochrome c with Pf1 virus

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em BioOrgânica

Neutralizing antibodies in Brazilian sera against three strains of human immunodeficiency virus type 1 (HIV-1)

The MN strain of HIV-1 is known to be more prevalent in Brazil, the BRU strain is more prevalent in Europe, and the NDK strain in Africa. It has been suggested in the literature to include different strains in the same vaccine against HIV-1. To contribute to the studies for the development of a universal vaccine, the occurrence of antibodies (Ab) against three HIV-1 strains (MN, BRU and NDK) was determined in serum samples from 85 HIV-1-positive patients, adult volunteers seen at the University Hospital of the Faculty of Medicine of Ribeirão Preto-USP. One-hundred tissue culture infective unit (TCIU) of the viruses reacted with serial dilutions of the sera (2x) and with MT4 cells added at a final concentration of 0.3 × 106 cells/ml, and a cytopathic effect was observed on the 7th and 11th days of incubation. Titres of less than 1/50 were considered to be negative. In 129 tests, the sera were negative for one of the three strains: 40 for MN, 29 for BRU and 60 for NDK. There was a predominance of strains MN and BRU, most of them presenting titres from 1/50 to 1/200. Titres for NDK were detected in 25 sera. We conclude that there seems to be a predominance of strains MN and BRU among the individuals from the region tested; however, the detection of sera with positive NKD titres indicates the need for further studies of this strain in other populations and regions of Brazil

Cytotoxicity in L929 fibroblasts and inhibition of herpes simplex virus type 1 Kupka by estuarine cyanobacteria extracts

The cyanobacteria are known to be a rich source of metabolites with a variety of biological activities in different biological systems. In the present work, the bioactivity of aqueous and organic (methanolic and hexane) crude extracts of cyanobacteria isolated from estuarine ecosystems was studied using different bioassays. The assessment of DNA damage on the SOS gene repair region of mutant PQ37 strain of Escherichia coli was performed. Antiviral activity was evaluated against influenza virus, HRV-2, CVB3 and HSV-1 viruses using crystal violet dye uptake on HeLa, MDCK and GMK cell lines. Cytotoxicity evaluation was performed with L929 fibroblasts by MTT assay. Of a total of 18 cyanobacterial isolates studied, only the crude methanolic extract of LEGE 06078 proved to be genotoxic (IF > 1.5) in a dose-dependent manner and other four were putative candidates to induce DNA damage. Furthermore, the crude aqueous extract of LEGE 07085 showed anti- herpes type 1 activity (IC50 = 174.10 μg dry extract mL−1) while not presenting any cytotoxic activity against GMK cell lines. Of the 54 cyanobacterial extracts tested, only the crude methanolic and hexane ones showed impair on metabolic activity of L929 fibroblasts after long exposure (48–72 h). The inhibition of HSV-1 and the strong cytotoxicity against L929 cells observed emphasizes the importance of evaluating the impact of those estuarine cyanobacteria on aquatic ecosystem and on human health. The data also point out their potential application in HSV-1 treatment and pharmacological interest.

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.