RESUMO
Group A rotaviruses are the major cause of severe gastroenteritis in young children worldwide. Because rotavirus vaccination appeared imminent, a nationwide surveillance program was organized between October 1996 and October 1998 in the largest Argentine cities. Surveillance for disease burden, rotavirus detection, and rotavirus typing was undertaken at nine locations. Results showed rotavirus to be associated with 42% of diarrhea admissions. Although the prevalent G types changed from year to year, common G types were found in 96% of the cases and were usually associated with common P types. Uncommon G types, G9 and G5, were found at low prevalence and uncommon G/P combinations occurred at almost every study site. These data suggest that a rotavirus vaccine could substantially decrease the rotavirus disease burden in Argentina, but that introduction of a vaccine should be accompanied by a concurrent surveillance system.
Assuntos
Vigilância da População , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/isolamento & purificação , Distribuição por Idade , Argentina/epidemiologia , Pré-Escolar , Diarreia/epidemiologia , Diarreia/virologia , Genótipo , Humanos , Lactente , Recém-Nascido , Rotavirus/classificação , Rotavirus/imunologia , Estações do Ano , SorotipagemRESUMO
BACKGROUND: Knowledge of the impact of rotavirus-associated disease on the health care systems of South America can aid in defining strategies for diagnosis, management and prevention. Up to date information on the impact of rotavirus disease in South America is scarce. AIM: To determine prospectively the impact of rotavirus disease as a cause of medical visits and hospitalizations at three large sentinel pediatric hospitals in Argentina, Chile and Venezuela. METHODS: A 2-year prospective surveillance for rotavirus-associated medical visits and hospitalizations was conducted during 1997 through 1998 at three large sentinel public hospitals, one each in Argentina, Chile and Venezuela. A common surveillance protocol was implemented at the three sites, and a representative number of nonbloody diarrhea stool samples from children <36 months of age were tested for rotavirus by enzyme-linked immunosorbent assay. RESULTS: For our target age group, acute diarrhea-associated medical visits/hospitalizations represented 41%/2%, 5%/6% and 9%/13% of all medical visits/all hospitalizations at the Argentinean, Chilean and Venezuelan sites, respectively (P < 0.001 for difference among the three sites). Rotavirus detection rates among a total of 5,801/1,256 medical visit/hospitalization diarrhea stool samples tested were 39%/71% in Argentina, 34%/47% in Chile and 29%/38% in Venezuela (P < 0.01 by chi square for difference among the three sites). Rotavirus was associated with a mean of 1.5, 1.8 and 3% of total medical visits and 1.6, 2.8 and 5% of hospitalizations among children <36 months of age at the Argentinean, Chilean and Venezuelan sites, respectively. Seasonality was evident for medical visits at all three sites (although less striking in Chile) with peak activity occurring between November and May. Rotavirus-associated hospitalizations had a marked peak in Venezuela, represented largely by short stays, but not in Argentina and Chile. CONCLUSIONS: Rotavirus was a significant cause of medical visits at all three sentinel sites. Rotavirus caused less hospitalizations than previously reported in Argentina and Chile. On the basis of our findings we estimate that approximately 106,000/ 21,000, 48,000/8,000 and 98,000/31,000 rotavirus-associated medical visits/hospitalizations occur yearly in Argentina, Chile and Venezuela, respectively.
Assuntos
Hospitalização/estatística & dados numéricos , Visita a Consultório Médico/estatística & dados numéricos , Infecções por Rotavirus/epidemiologia , Argentina/epidemiologia , Pré-Escolar , Chile/epidemiologia , Diarreia/virologia , Ensaio de Imunoadsorção Enzimática , Feminino , Hospitais Pediátricos/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Prospectivos , Rotavirus/isolamento & purificação , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/economia , Vigilância de Evento Sentinela , Venezuela/epidemiologiaRESUMO
Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diarrhea episodes among 214 children (<18 months old) prospectively monitored for diarrhea in Mexico City. Stool samples were tested by EIA and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. EIA was less sensitive (74%) and equally specific, compared with RT-PCR analysis using type-common primers for HAstV detection. Of 31 HAstV isolates, EIA typed 18 (69%) of 26 EIA-positive samples, and RT-PCR analysis typed 26 (84%) of 31 RT-PCR-positive samples. Phylogenetic analysis of the 3' end of the capsid region (363 nucleotides) confirmed the type assignment by EIA and RT-PCR analysis and determined the type for 5 previously untyped samples. Six HAstV antigenic types cocirculated in the community: HAstV-2 (42%), HAstV-4 (23%), HAstV-3 (13%), HAstV-1 (10%), HAstV-5 (6%), and HAstV-7 (6%). RT-PCR and sequence analysis provided more detailed epidemiology of HAstV in the community than did antigenic detection methods.
Assuntos
Infecções por Astroviridae/epidemiologia , Diarreia Infantil/epidemiologia , Mamastrovirus/classificação , Infecções por Astroviridae/virologia , Sequência de Bases , Células CACO-2 , Primers do DNA , Diarreia Infantil/virologia , Surtos de Doenças , Fezes/virologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Lactente , Recém-Nascido , Masculino , Mamastrovirus/genética , Mamastrovirus/isolamento & purificação , México/epidemiologia , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Estudos Prospectivos , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Estudos Soroepidemiológicos , População Urbana/estatística & dados numéricosRESUMO
We report a naturally occurring human astrovirus (HAstV) strain detected in two different geographic locations. We identified two isolates of this strain in a diarrhea outbreak at a child care center in Houston, Texas; and two isolates in diarrhea stool samples from two children in Mexico City. All four isolates were detected in stool samples by enzyme immunoassay (EIA). One of the Mexican isolates was typed by EIA and all four isolates were HAstV-5 by typing RT-PCR. The four isolates were >97% nucleotide-identical in two different genomic regions: ORF1a (246 nt), and the 3' end of the genome (471 nt). One isolate from each geographic location was further sequenced in the transition region from ORF1b to ORF2 (1255 nt) and this region of the two isolates showed > or = 99% nt identity. Phylogenetic analyses of sequences of eight HAstV antigenic types and the novel strain in the transition region demonstrated the new strain being closely related to HAstV-3 in ORF1b, but closest to HAstV-5 in ORF2. These results and high sequence identity among all HAstV antigenic types in the transition region and RNA structural predictions supported a potential recombination site at the ORF1b/ORF2 junction. This is the first evidence that recombination occurs among human astroviruses.
Assuntos
Surtos de Doenças , Gastroenterite/epidemiologia , Mamastrovirus/classificação , Mamastrovirus/genética , Recombinação Genética , Animais , Infecções por Astroviridae/epidemiologia , Infecções por Astroviridae/virologia , Creches , Pré-Escolar , Fezes/virologia , Gastroenterite/virologia , Humanos , Técnicas Imunoenzimáticas , Mamastrovirus/isolamento & purificação , México/epidemiologia , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Filogenia , RNA Viral/química , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Sorotipagem , Texas/epidemiologia , População UrbanaRESUMO
To determine whether naturally acquired serum IgA and IgG antibodies were associated with protection against rotavirus infection and illness, a cohort of 200 Mexican infants was monitored weekly for rotavirus excretion and diarrhea from birth to age 2 years. Serum samples collected during the first week after birth and every 4 months were tested for anti-rotavirus IgA and IgG. Children with an IgA titer >1:800 had a lower risk of rotavirus infection (adjusted relative risk [aRR], 0.21; P<.001) and diarrhea (aRR, 0. 16; P=.01) and were protected completely against moderate-to-severe diarrhea. However, children with an IgG titer >1:6400 were protected against rotavirus infection (aRR, 0.51; P<.001) but not against rotavirus diarrhea. Protective antibody titers were achieved after 2 consecutive symptomatic or asymptomatic rotavirus infections. These findings indicate that serum anti-rotavirus antibody, especially IgA, was a marker of protection against rotavirus infection and moderate-to-severe diarrhea.
Assuntos
Anticorpos Antivirais/sangue , Biomarcadores/sangue , Diarreia Infantil/sangue , Infecções por Rotavirus/imunologia , Rotavirus/imunologia , Estudos de Coortes , Fatores de Confusão Epidemiológicos , Diarreia Infantil/epidemiologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Incidência , Lactente , Recém-Nascido , México/epidemiologia , Infecções por Rotavirus/sangueRESUMO
Human caliciviruses (HuCVs) are increasingly recognized as common pathogens that cause acute sporadic diarrhea in children; however, regional antigenic and genetic diversity complicate detection techniques. Stool samples from children seeking medical attention in 2 outpatient clinics, a large emergency department, and 2 hospital wards were evaluated for HuCVs by reverse transcription-polymerase chain reaction, using primers based on a conserved sequence of the polymerase region of a previously sequenced Chilean strain. HuCVs were detected in 53 (8%) of 684 children 1 month to 5 years of age (mean, 13 months). Detection occurred year-round without a clear seasonal peak, and detection frequency declined from 16% in 1997 to 2% in 1999. The decline may have been due to a change in virus genotype. HuCVs are a significant pathogen of acute sporadic diarrhea in Chilean children, and continuous characterization of genetic diversity will be crucial for appropriate detection.
Assuntos
Caliciviridae/isolamento & purificação , Diarreia/virologia , Doença Aguda , Pré-Escolar , Chile , Fezes/virologia , Humanos , Lactente , Fatores de TempoRESUMO
Human caliciviruses (HuCVs) contain two genera: "Norwalk-like viruses" (NLVs) and "Sapporo-like viruses" (SLVs). The importance of the two genera as a cause of acute gastroenteritis of infants and children remains unknown. Beginning in 1989, a birth cohort of children in Mexico was enrolled and monitored for acute gastroenteritis. A subset of 115 diarrhea stool specimens from 76 children and 66 non-diarrhea stool specimens from 64 children was examined for HuCVs by RT-PCR by using a primer pair (p289/290) that detects both NLVs and SLVs. Twenty-two (19%) of the 115 diarrhea stool specimens and 5 (7%) of 66 non-diarrhea stool specimens produced RT-PCR products of expected size (319 bp for NLVs and 331 bp for SLVs). Twenty of the twenty-seven strains were cloned and sequenced. Pairwise sequence analysis showed that 9 (60%) and 6 (40%) of the 15 strains from the diarrhea stools were NLVs and SLVs, respectively. The same proportions of NLVs (60%) and SLVs (40%) were observed in the non-diarrhea stools. Strains in the NLV genus could be further divided into four clusters: Lordsdale, MxV, and HV and one potentially new cluster. Strains in the SLV genus could be divided into three clusters: Sapporo/82, Lon/92, and a potentially new cluster. Strains from the Lordsdale cluster were the most common among these children. The findings of both genera and multiple clusters of HuCVs co-circulating and the identification of new strains of HuCVs in the population justify the need for future studies of HuCVs in infants and children.
Assuntos
Infecções por Caliciviridae/epidemiologia , Caliciviridae/genética , Gastroenterite/epidemiologia , Variação Genética , Vírus Norwalk/genética , Caliciviridae/isolamento & purificação , Infecções por Caliciviridae/virologia , Pré-Escolar , Gastroenterite/virologia , Humanos , Lactente , México/epidemiologia , Vírus Norwalk/isolamento & purificação , Prevalência , RNA Viral , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Knowledge of the antigenic diversity of rotaviruses circulating in a region should be acquired before introducing a rotavirus vaccine. In a collection of 151 rotavirus-positive samples from Mendoza, Argentina, strain diversity was evaluated utilizing G-typing monoclonal antibodies (MAbs), reverse-transcriptase-polymerase chain reaction (RT-PCR) G and P typing, and electropherotyping (PAGE). The G type of 137 (91%) specimens was determined. Typing MAb reactivity with the homologous type ranged from 25-94%. For the seven G1 MAbs utilized, 28 patterns of reactivity among 68 G1 strains occurred. For the 48 G2 strains, six patterns of reactivity occurred utilizing three G2-specific MAbs. Of the 92 samples G- and P-typed by reverse-transcriptase-polymerase chain reaction, 89% had single G/P combinations: eight G1[P4], one G1[P6], twelve G1[P8], 58 G2 [P4], and two G2 [P6]. Nine samples had more than one G type with a single P type, one sample had two P types associated with one G type, and one sample contained multiple G and P types. Twenty-nine PAGE patterns occurred for all G types, but differences of antigenic reaction did not predict differences in migration of gene segments 7, 8, and 9. For three specimens showing discordant results between G type by enzyme-linked immunosorbent assay (EIA) and RT-PCR, we observed unexpected electropherotypes. Complementary evaluation by RT-PCR and MAb-based EIA with multiple typing MAbs revealed genetic and antigenic diversity of circulating rotaviruses, including extensive intratypic variation of the G1 and G2 neutralization antigens, in Mendoza during a single season of rotavirus activity.
Assuntos
Antígenos Virais/análise , Capsídeo/análise , Infecções por Rotavirus/virologia , Rotavirus/classificação , Anticorpos Monoclonais/imunologia , Variação Antigênica , Antígenos Virais/imunologia , Argentina/epidemiologia , Capsídeo/imunologia , Eletroforese em Gel de Poliacrilamida , Fezes/virologia , Variação Genética , Humanos , Lactente , Recém-Nascido , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rotavirus/genética , Rotavirus/imunologia , Infecções por Rotavirus/epidemiologiaRESUMO
BACKGROUND: Human calciviruses (HuCVs) cause diarrhea outbreaks associated with consumption of contaminated food and water. Seroepidemiological studies in developing countries, suggest that HuCVs can cause acute gastroenteritis in children. AIM: To study the presence of Norwalk (NV) and Mexico (MX) virus, two HuCVs, in stools of Chilean children from different settings. SUBJECTS AND METHODS: ELISA tests for NV and MX were performed in 677 stool samples for children aged 0 to 132 years old, with acute diarrhea occurring in day care centers or consulting in outpatient clinics or emergency rooms. We also studied eight samples from children involved in a diarrhea outbreak that occurred in a rural community in 1992. A subset of samples was tested with polymerase chain reactions using different primers. RESULTS: Only one sample from a child with acute diarrhea occurring in a day care center was positive for HuCV by polymerase chain reaction. Three samples from the outbreak were positive by the latter method and by ELISA. The HuCV obtained from the day care center was genetically different from other known HuCV. CONCLUSIONS: Despite the high seroprevalence, NV and MX viruses were detected in a very low proportion of Chilean children stools.
Assuntos
Infecções por Caliciviridae/virologia , Diarreia Infantil/virologia , Vírus Norwalk/isolamento & purificação , Doença Aguda , Adolescente , Caliciviridae/genética , Criança , Pré-Escolar , Chile/epidemiologia , Diarreia Infantil/epidemiologia , Fezes/virologia , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
Norwalk virus (NV) and Mexico (MX) virus represent distinct genetic clusters within the same genus of human caliciviruses (CVs), a major cause of diarrhea in adults. The magnitude and potential risk factors of human CV infection in populations from Santiago and Punta Arenas, Chile, were assessed. Individuals (n = 1,864) gave a blood sample and answered a questionnaire during a household survey. Sera were tested for antibody to NV and MX virus with use of recombinant capsid antigens. Overall, NV and MX virus seroprevalence rates were 83% and 91% in Santiago vs. 67% and 90% in Punta Arenas, respectively (P < .001 for NV virus). Lower socioeconomic status and increasing age were risk factors for infection with both viruses (P < .001). Consumption of seafood, consumption of vegetables, and child care center attendance were population risk factors for infection, but the association of a factor with a virus depended on the city. Prevention of human CV infections will require individual assessment in different communities.
Assuntos
Infecções por Caliciviridae/epidemiologia , Vírus Norwalk , Adolescente , Adulto , Fatores Etários , Anticorpos Antivirais/sangue , Caliciviridae , Infecções por Caliciviridae/sangue , Infecções por Caliciviridae/imunologia , Criança , Pré-Escolar , Chile/epidemiologia , Cidades/epidemiologia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Vírus Norwalk/imunologia , Fatores de Risco , Estudos Soroepidemiológicos , Classe SocialRESUMO
BACKGROUND: Human milk contains a 46 kDa mucin-associated glycoprotein, lactadherin, which binds specifically to rotavirus and inhibits its replication. This study tested the hypothesis that lactadherin protects against symptoms of rotavirus infection. METHODS: 200 infants in Mexico City were recruited at birth and monitored by regular stool EIA for rotavirus, serology, and recording of feeding and stool patterns. Milk samples were obtained from the mothers weekly until 4 weeks post partum then monthly. The sample taken immediately before an infant's episode of rotavirus infection was assayed for lactadherin, butyrophilin, mucin, and secretory IgA. An infection was defined as symptomatic if diarrhoea occurred in the 5 days before or after detection of the virus. FINDINGS: 31 infants developed rotavirus infection; 15 were symptomatic and 16 had no symptoms. The median concentration of lactadherin in the milk samples (obtained 4-41 days [median 13] before the infection) was 48.4 (range 5.6-180) microg/mL in the asymptomatic group and 29-2 (6.2-103-4) microg/mL in the symptomatic group. Although these medians did not differ significantly, in logistic regression analysis adjusted for age at infection and secretory IgA concentration there was a significant difference between the groups (p=0O01). No association between symptom status and concentrations of butyrophilin, mucin, or secretory IgA was found. INTERPRETATION: Protection against rotavirus by human milk is associated with the glycoprotein lactadherin. This association is independent of products of the secretory immune system.
Assuntos
Antígenos de Superfície/metabolismo , Proteínas do Leite/metabolismo , Leite Humano/imunologia , Infecções por Rotavirus/imunologia , Adulto , Anticorpos Antivirais/metabolismo , Aleitamento Materno , Diarreia Infantil/imunologia , Fezes/virologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , México , Valores de Referência , Rotavirus/imunologia , Replicação Viral/imunologiaRESUMO
BACKGROUND: Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. Our aim was to characterize the epidemiology of rotavirus antigenic types over time in Santiago, Chile. METHODS: We prospectively obtained 2097 stool samples for rotavirus testing, VP7 (G1 to G4) and VP4 (P4, P6, P8, P9) typing from children with diarrhea evaluated in emergency rooms of 5 base hospitals of Santiago. In addition 256 rotavirus-positive samples collected between 1985 and 1987 in the north health care area of Santiago were studied. RESULTS: Of 995 rotavirus-positive samples obtained 825 (82%) were typable for 1 or more VP7 types. G1 represented 81% of the G-typed samples during 1993 through 1995 and 77% during 1985 through 1987, predominating in all health care areas. G2 was next most common in all 5 areas, representing 6 to 23% of typed samples, with 1 area, the Southeast concentrating a significantly higher number of G2 infections. G2 declined from 35% of rotavirus-positive samples in 1993 to 0% in 1995 (P < 0.001), and from 25% to 2% in the north health care area from 1985 to 1987 (P < 0.001). G4 was uncommon and significantly more prevalent in 1985 through 1987 than in 1993 through 1995 (7% vs. 3%, P = 0.015). G3 was not detected. G1P8 (53%) and G2P4 (16%) combinations were by far the most commonly detected G-P associations. CONCLUSIONS: In Santiago, Chile, rotavirus antigenic type G1P8 has been highly prevalent and G2P4 has circulated in cycles. Differences in epidemiology of rotavirus antigenic types worldwide may prove to be relevant in efficacy of rotavirus vaccines.
Assuntos
Infecções por Rotavirus/epidemiologia , Rotavirus/genética , Criança , Chile/epidemiologia , Diarreia/virologia , Ensaio de Imunoadsorção Enzimática , Humanos , Reação em Cadeia da Polimerase , Estudos Prospectivos , Rotavirus/classificaçãoRESUMO
BACKGROUND: Rotavirus is the leading cause of severe diarrhea in infants. To provide a base line for assessing the efficacy of rotavirus vaccines, we evaluated the protection that is conferred by natural rotavirus infection. METHODS: We monitored 200 Mexican infants from birth to two years of age by weekly home visits and stool collections. A physician assessed the severity of any episodes of diarrhea and collected additional stool specimens for testing by enzyme immunoassay and typing of strains. Serum collected during the first week of life and every four months thereafter was tested for antirotavirus IgA and IgG. RESULTS: A total of 316 rotavirus infections were detected on the basis of the fecal excretion of virus (56 percent) or a serologic response (77 percent), of which 52 percent were first and 48 percent repeated infections. Children with one, two, or three previous infections had progressively lower risks of both subsequent rotavirus infection (adjusted relative risk, 0.62, 0.40, and 0.34, respectively) and diarrhea (adjusted relative risk, 0.23, 0.17, and 0.08) than children who had no previous infections. No child had moderate-to-severe diarrhea after two infections, whether symptomatic or asymptomatic. Subsequent infections were significantly less severe than first infections (P=0.024), and second infections were more likely to be caused by another G type (P=0.054). CONCLUSION: In infants, natural rotavirus infection confers protection against subsequent infection. This protection increases with each new infection and reduces the severity of the diarrhea.
Assuntos
Diarreia Infantil/microbiologia , Infecções por Rotavirus/imunologia , Anticorpos Antibacterianos/sangue , Fatores de Confusão Epidemiológicos , Diarreia Infantil/classificação , Diarreia Infantil/imunologia , Fezes/virologia , Humanos , Imunidade Inata , Lactente , Recém-Nascido , Estudos Longitudinais , Recidiva , Risco , Rotavirus/classificação , Rotavirus/imunologia , Rotavirus/isolamento & purificação , Infecções por Rotavirus/microbiologiaRESUMO
Understanding of the protective effect provided by natural rotavirus infections against subsequent rotavirus infections is required for evaluating vaccine development programs. Prior studies of the protective efficacy of natural infections and correlates of natural protection are reviewed and results from several studies presented only in abstract form are summarized to provide a current assessment of knowledge in this area. Six cohort studies have reported rates for the protective efficacy of a natural rotavirus infection against subsequent infection, diarrhea, or severe diarrhea. These efficacy estimates ranged from 0 to 100% and are not directly comparable because of differences in methodology and population monitored. Results from other study designs also have been confusing, until recently. Recent studies have identified immunologic correlates of protection and studies from a cohort of intensely monitored Mexican children promise to provide a comprehensive assessment of the strength of the protective effect of natural rotavirus infection.
Assuntos
Infecções por Rotavirus/prevenção & controle , Rotavirus/imunologia , Animais , Estudos de Coortes , Humanos , Lactente , México/epidemiologia , Infecções por Rotavirus/epidemiologiaRESUMO
Two-hundred Mexican children monitored from birth to 2 years of age in a cohort study of diarrhea were tested for Norwalk virus (NV) and Norwalk-related virus infection. Blood was collected quarterly and tested by an enzyme immunoassay (EIA) using the recombinant NV (rNV) particles as antigen. Stool was collected weekly and tested by an EIA using hyperimmune anti-sera from animals immunized with rNV and a reverse transcription-polymerase chain reaction (RT-PCR) with primers in the RNA polymerase region of NV. A high prevalence of serum antibody to NV (85% at age 2 years) was found by the antibody EIA. In 54 stool specimens selected from children who developed a high titer of serum antibody to rNV, none was positive for NV by the antigen EIA, but 6 yielded products by the RT-PCR. One stool specimen (MX virus) yielded a 3.3 kb RT-PCR product from the 3' end of the viral genome. The MX virus cDNA has a genomic organization like other caliciviruses. Sequence comparison showed that MX virus shares 80% nucleic acid and 91% amino acid sequence identity with Snow Mountain agent (SMA), but only 62% and 60% identity, respectively, with NV in the RNA polymerase region, suggesting that MX virus is a SMA-like virus.
Assuntos
Anticorpos Antivirais/sangue , DNA Viral , Diarreia/virologia , Vírus Norwalk/genética , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Sequência de Bases , Caliciviridae/genética , Pré-Escolar , Clonagem Molecular , Estudos de Coortes , DNA Complementar , Diarreia/epidemiologia , Fezes/virologia , Humanos , Técnicas Imunoenzimáticas , Lactente , Recém-Nascido , México/epidemiologia , Dados de Sequência Molecular , Vírus Norwalk/imunologia , Filogenia , Reação em Cadeia da Polimerase , Prevalência , DNA Polimerase Dirigida por RNA , Coelhos , Homologia de Sequência de AminoácidosRESUMO
Some rotavirus strains, including vaccine candidates, have been demonstrated to cause hepatitis in immunodeficient and malnourished mice and to grow in human liver cells. To determine whether rotavirus spreads outside the intestine in naturally infected children, we examined tissues from four immunodeficient children affected with severe combined immunodeficiency disease, acquired immunodeficiency disease syndrome, or DiGeorge syndrome. Chronic rotavirus-related diarrhea, which persisted until death, had also developed in each child. Using indirect immunoperoxidase techniques, we identified rotavirus antigen in the liver and kidney with a hyperimmune guinea pig antiserum prepared to double-shelled rotavirus particles. Similar immunostaining with an antiserum to a rotavirus nonstructural protein (NS26) provided evidence of active virus replication. The observed reactivity was eliminated specifically when serial sections were immunostained with the same antiserum that had been absorbed with either double-shelled rotavirus particles or NS26. Immunostaining was not observed in the liver of children with other diseases (alpha 1-antitrypsin deficiency, inspissated bile syndrome, and acute rejection of a transplanted liver). These findings demonstrate that rotavirus infections in children can extend beyond the intestinal tract. Further studies are warranted to determine whether extraintestinal rotavirus replication occurs in children without severe immunodeficiency, such as malnourished children.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Síndrome de DiGeorge/complicações , Hepatite Viral Humana/microbiologia , Nefropatias/microbiologia , Infecções por Rotavirus/complicações , Imunodeficiência Combinada Severa/complicações , Diarreia Infantil/microbiologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Lactente , Masculino , Rotavirus/isolamento & purificação , Rotavirus/fisiologia , Replicação ViralRESUMO
OBJECTIVE: Human enteric adenovirus (EAd) types 40 and 41 cause diarrhea in young children, but little is known about their association with outbreaks of diarrhea in the child care setting. This study evaluated EAd as a cause of outbreaks of diarrhea among infants and toddlers in day care centers. DESIGN: Stool specimens were collected weekly regardless of symptoms during four periods from January 1986 to April 1991, from children 6 to 24 months of age enrolled in prospective studies of diarrhea in day care centers. All diarrhea stool specimens were tested for bacterial enteropathogens, rotavirus, and Giardia lamblia. A total of 131 outbreaks occurred during the study. No etiologic agent was identified in 77 outbreaks. Stool specimens from 75 of these 77 outbreaks and from another 21 outbreaks of diarrhea with a known cause were evaluated for EAd with a monoclonal antibody-based enzyme immunoassay. RESULTS: A total of 4402 stool specimens from 613 children from these 96 outbreaks was tested for EAd. The virus was detected in specimens collected during 10 outbreaks, 3 of which occurred in 1986, 3 in 1988, 1 in 1989, 1 in 1990, and 2 in 1991. Of 249 children, 94 (38%) in these 10 EAd outbreaks were infected with EAd. In 51 children (54%) the infection was symptomatic and in 43 (46%) it was asymptomatic. Outbreaks lasted 7 to 44 days (mean 24.5 days). Duration of EAd excretion ranged from 1 to 14 days (mean 3.9 days), with excretion occurring from 7 days (mean 2.6) before diarrhea began to 11 days (mean 5.3 days) after diarrhea stopped. CONCLUSION: Enteric adenovirus types 40 and 41 are an important cause of outbreaks of diarrhea among children attending day care centers, often involve children in more than one room, and frequently produce asymptomatic infection.
Assuntos
Infecções por Adenovirus Humanos/epidemiologia , Creches , Diarreia Infantil/epidemiologia , Surtos de Doenças , Infecções por Adenovirus Humanos/microbiologia , Adenovírus Humanos/isolamento & purificação , Aeromonas/isolamento & purificação , Animais , Caliciviridae/isolamento & purificação , Diarreia Infantil/microbiologia , Fezes/microbiologia , Giardia/isolamento & purificação , Humanos , Técnicas Imunoenzimáticas , Lactente , Estudos Longitudinais , Estudos Prospectivos , Rotavirus/isolamento & purificação , Sensibilidade e Especificidade , Shigella/isolamento & purificação , Texas/epidemiologiaRESUMO
Human rotaviruses are the major, recognized cause of infantile diarrhea worldwide. Characterization of naturally occurring human isolates indicates that there are six human rotavirus serotypes, four of which (serotype 1 to 4) are widespread. We utilized monoclonal antibodies specific for the VP of serotypes 1, 2, 3, and 4 as capture antibody in a sandwich enzyme-linked immunosorbent to serotype rotaviruses directly in stool samples. The stool samples were collected from 1983 through 1986, from two epidemiologic studies in the area of Buenos Aires, Argentina. All four serotypes assayed were found Serotype 2 and 3 viruses, which were detected most frequently in 1983 and 1984, were virtually undetected in 1985 and 1986 (chi 2 = 23, P = less than 0.001 for this difference). No significant difference was noted among the three collection sites for serotype prevalence. These results indicate that the changing predominance of rotavirus serotype in a given region can involve multiple serotypes at the same time. Analysis of an outbreak of diarrhea in two neighboring families which occurred during a prospective study of community diarrhea documented inter- and intra-family spread of one serotype of virus.