RESUMO
Bovine torovirus (BToV) is an enteric pathogen that may cause diarrhea in calves and adult cattle, which could result in economic losses due to weight loss and decreased milk production. This study aimed to report the presence, the genetic characterization and the evolution of BToV in calves in Uruguay. BToV was detected in 7.9% (22/278) of fecal samples, being identified in dairy (9.2%, 22/239) but not beef (0.0%, 0/39) calves. BToV was detected in both diarrheic (14%, 6/43) and non-diarrheic (13.2%, 5/38) dairy calves. In addition, BToV was detected in the intestinal contents of 14.9% (7/47) of naturally deceased dairy calves. A complete genome (28,446 nucleotides) was obtained, which was the second outside Asia and the first in Latin America. In addition, partial S gene sequences were obtained to perform evolutionary analyses. Nucleotide and amino acid substitutions within and between outbreaks/farms were observed, alerting the continuous evolution of the virus. Through Bayesian analysis using BEAST, a recent origin (mid-60s) of BToV, possibly in Asia, was estimated, with two introductions into Uruguay from Asia and Europe in 2004 and 2013, respectively. The estimated evolutionary rate was 1.80 × 10-3 substitutions/site/year. Our findings emphasize the importance of continued surveillance and genetic characterization for the effective management and understanding of BToV's global epidemiology and evolution.
Assuntos
Doenças dos Bovinos , Fezes , Genoma Viral , Filogenia , Infecções por Torovirus , Torovirus , Animais , Uruguai/epidemiologia , Bovinos , Torovirus/genética , Torovirus/isolamento & purificação , Torovirus/classificação , Fezes/virologia , Doenças dos Bovinos/virologia , Doenças dos Bovinos/epidemiologia , Infecções por Torovirus/veterinária , Infecções por Torovirus/virologia , Infecções por Torovirus/epidemiologia , Diarreia/virologia , Diarreia/veterinária , Diarreia/epidemiologia , Evolução MolecularRESUMO
Bovine torovirus (BToV) is an established enteric pathogen of cattle, but its occurrence in Brazilian cattle had not been reported until now. This article describes a survey on BToV in Brazil carried out on 80 fecal samples from diarrheic young and adult cattle, using a nested-RT-PCR targeting the nucleocapsid (N) gene. BToV was detected in 6.25% (5/80) of stool samples from three different geographic regions. Sequences analysis showed that Brazilian BToVs have a high degree of identity with European and Japanese BToVs and a lower degree of identity with North American Breda 1 strain. These results show that, albeit its low frequency and the scarce number of research on the field, BToV is still present amongst cattle populations.
Assuntos
Variação Genética , Infecções por Torovirus/veterinária , Torovirus/classificação , Animais , Brasil/epidemiologia , Bovinos , Europa (Continente)/epidemiologia , Japão/epidemiologia , Filogenia , Torovirus/genética , Infecções por Torovirus/epidemiologia , Infecções por Torovirus/virologiaRESUMO
Bovine torovirus (BoTV) is a pleomorphic virus with a spike-bearing envelope and a linear, non-segmented, positive-sense single-stranded RNA genome. This kidney-shaped virus is associated with diarrhea in calves and apparently has a worldwide distribution. This review provides details of the history and taxonomy of BoTV since its discovery in 1979. Information about virion morphology and architecture, antigenic and biological properties, viral genome, protein composition, thermal and chemical stability, and pH and proteolytic enzymes resistance is also summarized. A major focus of this review is to postulate a possible epidemiological cycle for BoTV, based on epidemiological data obtained in our studies and other published data, and progressing from the newborn calf to the adult animal. The distribution, host range, pathogenesis, disease and clinical signs (under experimental and natural exposure), pathology, diagnosis, prevention, treatment and control of BoTV infections are also described. In addition, a discussion of the zoonotic implications of torovirus-like particles detected in patients with gastroenteritis that resemble and cross-react with BoTV is presented. Hopefully, the findings described here will alert others to the existence of BoTV in cattle and its contribution to the diarrheal disease complex. This review also highlights the need for continual vigilance for potential zoonotic viruses belonging to the order Nidovirales, such as the SARS coronavirus.
Assuntos
Doenças dos Bovinos/virologia , Infecções por Torovirus/veterinária , Torovirus/genética , Animais , Bovinos , Doenças dos Bovinos/transmissão , Humanos , Infecções por Torovirus/virologia , ZoonosesRESUMO
OBJECTIVE: To determine the prevalence, fecal shedding pattern, and association of bovine torovirus (BoTV) with diarrhea in veal calves at time of arrival and periodically throughout the first 35 days after their arrival on a veal farm. ANIMALS: 62 veal calves. PROCEDURE: Fecal samples collected on days 0, 4, 14, and 35 after arrival were tested for BoTV by use of ELISA and reverse transcriptase-polymerase chain reaction (RT-PCR) assay. Paired serum samples obtained from blood collected on days 0 and 35 were analyzed for BoTV antibodies with a hemagglutination inhibition assay. Fecal samples were also screened for other enteric pathogens, including rotavirus, coronavirus, and Cryptosporidium spp. RESULTS: Fecal shedding of BoTV was detected in 15 of 62 (24%) calves by use of ELISA and RT-PCR assay, with peak shedding on day 4. A significant independent association between BoTV shedding and diarrhea was observed. In addition, calves shedding > or = 2 enteric pathogens were more likely to have diarrhea than calves shedding < or = 1 pathogen. Calves that were seronegative or had low antibody titers against BoTV (< or = 1:10 hemagglutination inhibition units) at arrival seroconverted to BoTV (> 4-fold increase in titer); these calves were more likely to shed virus than calves that were seropositive against BoTV at arrival. CONCLUSIONS AND CLINICAL RELEVANCE: Shedding of BoTV was strongly associated with diarrhea in neonatal veal calves during the first week after arrival at the farm. These data provide evidence that BoTV is an important pathogen of neonatal veal calves.
Assuntos
Doenças dos Bovinos/virologia , Diarreia/veterinária , Diarreia/virologia , Infecções por Torovirus/veterinária , Torovirus/isolamento & purificação , Torovirus/fisiologia , Eliminação de Partículas Virais , Animais , Anticorpos Antivirais/análise , Anticorpos Antivirais/sangue , Bovinos , Doenças dos Bovinos/diagnóstico , Colostro/imunologia , Infecções por Coronavirus/complicações , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/veterinária , Infecções por Coronavirus/virologia , Coronavirus Bovino/isolamento & purificação , Diarreia/complicações , Ensaio de Imunoadsorção Enzimática , Fezes/virologia , Imunoglobulina G/análise , Masculino , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rotavirus/isolamento & purificação , Infecções por Rotavirus/complicações , Infecções por Rotavirus/diagnóstico , Infecções por Rotavirus/veterinária , Infecções por Rotavirus/virologia , Torovirus/genética , Torovirus/imunologia , Infecções por Torovirus/complicações , Infecções por Torovirus/diagnóstico , Infecções por Torovirus/virologia , Cultura de VírusRESUMO
A case-control study of calves under 3 months of age was carried out by weekly visits to 15 farms in the canton of Tilarán, Costa Rica. Most farms were dedicated to beef or dual-purpose (DP) production. Faecal samples were collected over a 6-month period from a total of 194 calves with clinical signs and from 186 animals without clinical signs of diarrhoea as assessed by a scoring system. The samples were investigated for the presence of viruses, bacteria and parasites. Torovirus was detected for the first time in Costa Rica and was present in 14% of calves with diarrhoea and in 6% of the controls. Coronavirus and Rotavirus were less frequently encountered in either one of the groups (in 9 and 7% of scouring calves and in 1 and 2% of controls, respectively). Escherichia coli was detected in 94% of all the faecal samples, but isolates from only three samples from calves with diarrhoea contained the K99 antigen. Similarly, Salmonella was found only in scouring calves. Cryptosporidium oocysts were detected in animals with signs of diarrhoea, while other coccidia oocysts, Strongylida and Strongyloides eggs were frequently found in animals both with and without diarrhoea. A conditional logistic regression (CLR) analysis to compare healthy and scouring calves showed a significant difference with regard to the presence of Torovirus, Rotavirus and Coronavirus.
Assuntos
Doenças dos Bovinos/microbiologia , Diarreia/veterinária , Fezes/microbiologia , Animais , Estudos de Casos e Controles , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Coccídios/isolamento & purificação , Coronavirus/isolamento & purificação , Costa Rica/epidemiologia , Cryptosporidium/isolamento & purificação , Diarreia/microbiologia , Diarreia/parasitologia , Escherichia coli/isolamento & purificação , Fezes/parasitologia , Feminino , Modelos Logísticos , Masculino , Prevalência , Rotavirus/isolamento & purificação , Salmonella/isolamento & purificação , Strongyloides/isolamento & purificação , Torovirus/isolamento & purificação , Clima TropicalRESUMO
OBJECTIVE: To study the etiologic role of toroviruses as a cause of gastroenteritis in humans. METHODS: The design was a case-control study. We compared the rate of torovirus detection in fecal specimens from a selection of children with acute or persistent diarrhea and controls without diarrhea from a study of childhood diarrhea in an urban Brazilian slum. Stool samples were coded and tested in a blinded fashion for the presence of torovirus antigen by enzyme-linked immunosorbent assay, other enteropathogens, toxins and fecal leukocytes. RESULTS: Thirty-three children with acute diarrhea, 41 children with persistent diarrhea and 17 controls were enlisted in the study. Torovirus antigen was detected in 9 (27%) samples from children with acute diarrhea, 11 (27%) samples from children with persistent diarrhea and none of the samples from controls (P < 0.05). In addition the presence of enteroaggregative E. coli was associated with persistent diarrhea and the presence of Cryptosporidium oocysts was common although not significant (P = 0.08); torovirus and Cryptosporidium occurred in different subsets of samples, whereas torovirus and enteroaggregative Escherichia coli were commonly found in combination. CONCLUSIONS: These data indicate that toroviruses, alone or in combination with enteroaggregative E. coli, may play a pathogenic role in acute and possibly persistent diarrhea. Further studies are warranted to determine the etiologic role of toroviruses in gastroenteritis.
Assuntos
Antígenos Virais/análise , Diarreia/microbiologia , Infecções por Escherichia coli/complicações , Fezes/virologia , Gastroenterite/microbiologia , Infecções por Torovirus/complicações , Torovirus/imunologia , Doença Aguda , Animais , Brasil/epidemiologia , Pré-Escolar , Doença Crônica , Cryptosporidium/isolamento & purificação , Diarreia/epidemiologia , Ensaio de Imunoadsorção Enzimática , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Fezes/microbiologia , Feminino , Gastroenterite/epidemiologia , Humanos , Incidência , Lactente , Estudos Longitudinais , Masculino , Infecções por Torovirus/epidemiologia , Infecções por Torovirus/virologia , População UrbanaRESUMO
Os autores fazem a conceituaçäo do ectrópio e apontam os principais tipos, de acordo com a sua etiologia: traumáticos, iatrogênicos, senis, paralíticos, pós-tumorais, infecciosos espasmódicos, etc. Apontam os principais sintomas e sinais como: fechamento imcompleto dos olhos, conjuntivite, lacrimaçäo, úlceras corneanas, ceratite, fotofobia, perda da visäo. Além disso, o aspecto estético fica muito comprometido. Cuidam só do tratamento dos ectrópios cicatriciais e senis. Os primeiros säo tratados com enxertos de pele e os seguintes pelo método de Kuhnt-Szymanowski
Assuntos
Humanos , Ectrópio/cirurgia , Pálpebras/cirurgia , Cirurgia Plástica , Alopecia , Queimaduras , Queimaduras Químicas , Miíase , TorovirusRESUMO
No período de julho de 1986 a junho de 1987 foram contadas, quinzenalmete, larvas de Dermatobia hominis em 16 bovinos zebu x holandês, na faixa etária de 16 a 48 meses. Nódulos, com larvas de Dermatobia hominis ocorreram no decorrer do experimento, mas a partir de novembro, coincidindo com o início do período chuvoso, o seu número começou aumentar, atingindo pico máximo no mês de abril, final da estaçäo chuvosa. Esses valores sugerem uma influência ambiental, principalmente, da umidade relativa do ar e da precipitaçäo pluviométrica. Em relaçäo às seis regiöes do corpo dos bovinos, verificou-se uma maior porcentagem de nódulos na regiäo do costado com 40,10 pôr cento, seguida pela paleta com 30,37 pôr cento. Foram assinalados apenas quatro abscessos relacionados com a presença de bernes