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A C Linhares

Publications and source records attributed to A C Linhares.

At least 37 records · Page 2Linked to original sources
PubMed1994

Nosocomial transmission of an avian-like rotavirus strain among children in Belém, Brazil.

An atypical group-A rotavirus strain, with an electrophoretype displaying 5 segments in the first dsRNA size class, was detected among 3 hospitalized children less than 2 years old. Detection occurred initially 24 h after admission in a non-diarrhoeic child hospitalized because of acute respiratory infection. The second detection involved a child who occupied a different room within the same ward and who developed nosocomial diarrhoea 48 h later. A third case, also of hospital-acquired diarrhoea, was recorded in a child who occupied a bed in the same room as the second case and developed gastroenteritis 24 h following the second case's detection. In addition to the unusual, avian-like genomic profile, the strain was classified as serotype 2, based on a human VP7-specific enzyme-linked immunosorbent assay (ELISA). The question of whether these events reflect either a genomic rearrangement of a human rotavirus strain or a possible interspecies transmission will be further investigated through hybridization assays.

Brazil↗
PubMed1993

Rotavirus serotypes and electrophoretypes among children attending three paediatric hospitals in Belem, Brazil.

From March to September 1988 stool specimens of 101 hospitalized diarrhoeic infants and children, aged 1-24 months were examined by enzyme-linked immunosorbent assay (ELISA) for the presence of rotavirus antigen. This agent was found in 40 (40 per cent) of the 101 episodes of acute diarrhoea, and strains were both characterized by analysis of RNA in polyacrilamide gel and serotyped by ELISA using serotype-specific monoclonal antibodies. The highest frequency of rotavirus positivity was 80 per cent in the 16-18 month age group. All 11 (28 per cent) serotyped strains belonged to serotype 3 whereas absence of Vp7, the major outer capsid glycoprotein, did not allow serotyping in 29 (73 per cent) of the 40 rotavirus-positive specimens. Four distinct electrophoretypes were detected and the predominant one had the IbIIbIIIgIV a profile, accounting for 62 per cent of the classified strains. Unclear patterns did not allow us to determine the electrophoretype of six rotavirus strains. The clinical picture in study children was in general of moderate/severe nature.

Brazil↗
PubMed1993

National laboratory surveillance of viral agents of gastroenteritis in Brazil.

In 1984 an enzyme immunoassay for rotavirus and adenovirus developed in the Virology Department of the Oswaldo Cruz Foundation was distributed to laboratories in 14 Brazilian states as part of a project to survey viral agents in fecal specimens from children with diarrhea. The ensuing surveillance continued for 3 to 5 years, and in 1991 the results obtained by all laboratories that tested 300 or more fecal specimens were reviewed at a workshop held in Belém. These results showed that rotavirus had been detected in 13% to 20% of the specimens tested, with positive specimens appearing to peak in the May to September "winter" or dry season in Brazil's central and southern states but not in the more tropical northern areas. Adenovirus, detected in 0.7% to 5.5% of the specimens tested for it, showed no seasonal variations. Many other viral agents known to cause gastroenteritis (e.g., astrovirus, small round-structured viruses, calcivirus, and group C rotavirus) were detected at centers that used electron microscopy. Picobirnavirus, a novel agent not yet associated with gastroenteritis in humans, was found by polyacrylamide gel electrophoresis in specimens from a number of centers using this technique. Vaccines to prevent rotavirus that are currently under development would be of great use in Brazil, where rotavirus is the most common cause of childhood diarrhea. Improved diagnostics will be required to assess the importance of the other viral agents.

Acute Disease↗
PubMed1991

[Epidemiological studies among Amerindians of Rondônia. IV. Serological survey for rotavirus among Suruí and Karitiána].

The authors present the results of a sero-epidemiological survey for rotavirus antibodies conducted among the Suruí and Karitiána, two amerindian groups of Rondônia, Brazilian Amazonia. The results indicate high percentages of seropositivity for both groups (67.8% among the Suruí and 77.4% among the Karitiána using ELISA and 45.5% for the Suruí and 56.7% for the Karitiána using indirect immunofluorescence). Chi square tests indicated no statistically significant association between group and seropositivity. The results are discussed in the light of other studies conducted among Brazilian amerindian groups.

Antibodies, Viral↗
PubMed1990

Prevalence of human parvovirus (B19) and rubella virus infections in urban and remote rural areas in northern Brazil.

Sera from inhabitants of Belém, Pará (542 sera), Brazil and of members of 3 Brazilian tribes--Tiriyo/Alto Paru (near Surinam) (212 sera), Xicrin (128 sera), and Mekranoiti (121 sera)--of different age and sex groups were tested for the presence of specific antibody against human parvovirus (B19) (RIA) and rubella virus (latex agglutination test). Parvovirus (B19) IgG was found in 42.6% of the population sample from Belém but in only 4.7 to 10.7% of the members of the tribes. Rubella virus antibody was found in 72.7% of the sera from Belém but approaching a prevalence of 85-90% in age groups above 20 years. In the tribes rubella virus antibody was detected in 36.9 to 72.6% of all sera. There were remarkable sex differences of antibody prevalence in several age groups of the population from Belém and of the tribal populations. About a quarter of the skin rashes in Belém that were not attributable to infections with rubella, measles, or arboviruses were caused by recent B19 infections.

Adolescent↗
PubMed1989

Naturally occurring serotype 2/subgroup II rotavirus reassortants in northern Brazil.

Nine serotype 2 human rotavirus strains were isolated in a community-based longitudinal study in Northern Brazil. Five of these strains had a 'long' RNA electrophoretic pattern and all five strains were determined to belong to subgroup II by ELISA assay, in contrast to properties common to serotype 2 human rotaviruses previously characterized. Hybridization studies of one of these unusual strains with 32P-labelled mRNAs derived from the prototype human strains Wa (serotype 1, subgroup II) and S2 (serotype 2, subgroup I) suggested that it was generated by a reassortment event in nature, in which a subgroup II, 'long' electropherotype rotavirus exchanged its serotype-specific gene and gene number 10 for the equivalent genes from a serotype 2, 'short' electropherotype virus.

Brazil↗
PubMed1989

Longitudinal study of rotavirus infections among children from Belém, Brazil.

From December 1982 to March 1986 a group of 80 children between 0 and 3 years old who lived in the peripheral area of Belém, Brazil, were followed up for episodes of diarrhoea. A total of 441 diarrhoeal episodes were recorded and 36 (8.2%) were associated with rotavirus. This agent was the only pathogen in 50% of rotavirus-related episodes of acute diarrhoea, and strains were characterized by analysis of RNA in polyacrylamide gels. Forty-one belonged to subgroup II (long pattern) and five to subgroup I. Reinfections by rotavirus were noted in 12 children involving either the same or different subgroups. Ten distinct electrophoretypes were detected in the study period and the predominant one had the '1N2L' profile. The cumulative age-specific attack rate for diarrhoea reached 2.8 by the end of the first year of life; a frequency of 2.3 episodes of diarrhoea per child per year was observed throughout the complete investigation. In comparing the age-specific attack rates for diarrhoea between breast-fed and bottle-fed children, a peak at 6 months of age was noted in the former, and at 1 month in the latter. A comparison by Fischer's exact test (P = 0.21) provided no evidence for protection against clinical rotavirus disease by maternal milk. By the same test, however (P = 0.021), we found significant evidence that early rotavirus infections were more likely to be asymptomatic and that infections after 4 months were more likely to be symptomatic. The clinical picture in children with rotavirus-related diarrhoea was more severe than in those suffering from acute diarrhoea due to another agent.

Acute Disease↗
PubMed1986

Rotavirus infection in wild marsupials (Didelphis marsupialis) of the Amazon region.

Rotavirus was detected by enzyme-linked immunosorbent assay in faecal specimens collected from two (1.35%) of 148 marsupials trapped in the Amazon jungle environment. The positive samples were both from the "common opossum", Didelphis marsupialis. No infections were found in the stools of 198 animals belonging to other mammalian species: the latter included small rodents, chiropterans and primates. Electron microscopic examination of one (MA 5928) rotavirus-positive specimen showed a large number of empty particles. However, both rotavirus strains grew when inoculated in MA 104 cells (foetal Rhesus monkey kidney cells) producing clear cytopathogenic effect; indirect immunofluorescence technique of these cells showed a typical granular cytoplasmic fluorescence. The electrophoretic profile of strain MA 5928 showed a high grade of homology with that of SA 11, but also showed minor differences.

Animal Population Groups↗
PubMed1986

Prevalence of rotavirus antibody among isolated South American Indian communities.

Rotavirus antibody was detected by enzyme-linked immunosorbent assay (ELISA) in 711 (54.7%) of 1,299 serum samples collected from Indians belonging to 13 relatively isolated communities in the Amazon region. The Parakanãs Novos Indians showed prevalences of immunity of 17.9% and 10.7% by ELISA and the indirect fluorescent antibody technique, respectively. The remaining tribes, with the exception of the Yanomamis, Tucanos, and Xicrins, had percentages of positivity greater than 50% by at least one technique; among both the Kubenkrankreins and the Oyampis, all individuals over 20 years of age possessed antibody. High percentages of rotavirus positivity were observed among the Apalais, ranging from 56.0% (age group 31-40 years) to 74.0% (age group 0-5 years). In the Kubenkrankreins, Maiogongs, and Tucanos, the prevalences of rotavirus antibody regularly increased with age. ELISA and the indirect fluorescent antibody technique agreed in 72.5% of the specimens, but the former test yielded more positives than the latter.

Adolescent↗
PubMed1983

Acute diarrhoea associated with rotavirus among children living in Belém, Brazil.

Between January 1979 and December 1980, rotaviruses were detected in faecal samples from 122 (33.1%) of 369 diarrhoeic children less than six years old, living in Belém, Brazil. In 55 (45.1%) of the 122 rotavirus-positive specimens, no bacteria or parasite associated with gastro-enteritis was found. Salmonella typhimurium, Shigella and Escherichia coli were found in 92 (35%) of the 263 faecal specimens examined for bacterial pathogens. Rotaviruses were readily detected throughout the year, which may indicate no seasonal pattern of incidence in the Belém region. A comparison of the excretion of rotavirus was made between children of two socio-economic groups. Of 144 children from the higher level group, 63 (47.3%) excreted rotavirus, whereas only 12 (16.7%) of those from the lower level did so. Vomiting (68.0%) and fever (65.6%) were the main symptoms, other than diarrhoea, exhibited by the 122 rotavirus-positive children.

Acute Disease↗
PubMed1983

Electrophoretic study of the genome of human rotaviruses from Rio de Janeiro, São Paulo and Pará, Brazil.

Human rotaviruses from the states of Rio de Janeiro, São Paulo and Pará of Brazil were analysed by RNA electrophoresis. At least some bands characteristic of rotavirus double-stranded RNA were detected in 138 (86.8%) of 159 faecal samples in which the presence of rotavirus had been demonstrated by enzyme immunoassay. Of the RNA-positive samples, 18 (13.0%) were classified as subgroup 1, 94 (68.1%) as subgroup 2, and 26 (18.8%) could not be classified due to absence of visible bands 10 and 11. Subgroup 2 was more frequent in the three states. All strains of subgroup 1 detected in Rio de Janeiro were associated with a single short-lived school outbreak. All strains of subgroup 1 resembled each other in electrophoretic pattern, irrespective of geographical origin, although minor differences could be detected by co-electrophoresis. Subgroup 2, on the other hand, showed a great degree of electrophoretic heterogeneity and could be divided into several sub-categories.

Brazil↗
PubMed1981

An outbreak of rotavirus diarrhea among a nonimmune, isolated South American Indian community.

During July-August 1977, an outbreak of acute diarrhea occurred in an unusually isolated population, the Tiriyó Indians, who live in the north of Pará, Brazil, near the border with Surinam. Diarrhea was reported by 157 (70%) of the 224 Indians living in the village during the epidemic. There was one fatal case in a one year old child. Rotavirus was detected by electron microscopy in one fecal specimen collected from an acute case of diarrhea. Seroconversions were noted in 127 out of 168 (75.6%) paired serum samples tested for rotavirus antibody by counter-immunoelectrophoresis. With immunofluorescence based neutralization tests, rotavirus serotype 1 (Birmingham) was shown to be associated with the outbreak. The infection also boosted type 3 antibodies but this was most apparent in persons with pre-existing type 3 titers and the boost was not as great as with type 1. All age groups were affected. The proportion symptomatic was greatest in young children.

Adolescent↗
PubMedDate not supplied

Prevalence of human herpesvirus 6 antibody among isolated Amazonian Amerindian communities in Brazil.

Human herpesvirus 6 (HHV6) antibody was detected by the anticomplement immunofluorescence test in 65 of 592 serum samples (10.9%) obtained from Amerindians belonging to 4 remote communities inhabiting the Amazon Region of Brazil. Seropositivity rates ranged from 5.4% in the Oyampí to 14.9% in the Tucano. Among the Mekranoiti and Tiriyo, the seroprevalence rates were 12.5% and 11.8%, respectively. In children aged 0-10 years, the prevalences of HHV6 antibody ranged from 5.2% to 24.2%, among the Oyampí and Mekranoiti tribes, respectively. In the 11-20 and > 20 years old age groups, percentages of positivity ranged, in the former group, from 9.5% to 17.5% in the Oyampí and Tucano, respectively and, in the latter group, from 1.3% in the Oyampí to 14.8% in the Tucano. The prevalences of HHV6 antibody decreased regularly through the first 3 age-groups in the Mekranoiti and Tiriyo. In addition, frequencies of seropositivity were consistently higher in males than in females in the Mekranoiti (P < 0.05), Oyampí and Tiriyo tribes.

Adolescent↗
PubMedDate not supplied

Prevalence of human herpesvirus 6 antibody in the population of Belém, Pará, northern Brazil.

A total of 497 serum samples obtained from residents of 2 neighbourhoods (Terra-Firme and Guamá) in Belém, Pará, Brazil was tested for the presence of antibody to human herpesvirus 6 (HHV6), using an indirect immunofluorescence assay. The overall seroprevalence was 90%, with seropositivity rates ranging from 75% to 100% in the different age groups and sexes. There was a significant difference between the antibody prevalences in Terra-Firme and Guamá, 94% and 87%, respectively (P = 0.01). The geometric mean titres (GMT) of antibody to HHV6 declined from the first (< or = 2 years) to the sixth (31-40 years) age groups, and slightly increased (GMT > 50) among individuals older than 40 years.

Adolescent↗
PubMedDate not supplied

Epidemiology of rotavirus subgroups and serotypes in Belem, Brazil: a three-year study.

Rotavirus subgroups and serotypes were determined in 61 rotavirus-positive faecal samples obtained from children living in Belém, Brazil, followed up from birth to 3 years of age. Fifty-five (90%) of the specimens were subgrouped and the serotypes of 30 (49%) of them were determined. Subgroup II was detected in 49 (89%) of the 55 subgrouped strains. Serotype 1 was present in 15 (50%) of the 30 serotyped samples; serotypes 2, 3 and 4 were found in 30%, 3.3% and 16.7% respectively, of these specimens. Absence of Vp7, the major outer capsid glycoprotein, did not allow serotyping in 21 (34.4%) of the 61 rotavirus-positive specimens, and an unidentifiable new serotype was found in faeces of one child. In addition, 4 samples were classified as subgroup II serotype 2 (which is very unusual). Twelve (80%) of the 15 serotype 1 (subgroup II) specimens were collected from children (5 of them asymptomatic) during their first year of life. All 9 serotype 2 (subgroups I, II, or not determined) samples were detected during the second and third years of life, 7 (77.8%) of them were related to apparent infections. The 5 serotype 4 (subgroup II) samples were obtained throughout the study period, and were associated with both symptomatic (3 cases) and asymptomatic infections. Thirteen children had more than 1 rotavirus infection. Three had 3 successive infections. In 3 cases, the initial infection (either symptomatic or asymptomatic) caused by serotype 1, was followed by a subsequent diarrhoeic episode associated with serotype 2.

Age Factors↗
PubMedDate not supplied

[Biosafety in the laboratory].

The occurrence of laboratory-acquired infections have elicited in the last ten years an intense interest in methods and procedures for the safe handling of microbiological material. The major laboratory safety problem is aerial transmission, however, protection against airborne hazards is efficiently achieved by the use of microbiological safety cabinets. Biosafety rules should be strictly followed by all members of a laboratory. Evaluation of these procedures should be effectively performed by an independent biosafety committee. The upsurge of AIDS should stimulate the adoption of safe working procedures in the laboratory.

Accident Prevention↗