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Serological Survey (serological + survey)
Selected AbstractsSerological survey of leptospiral infection in kennelled dogs in ItalyJOURNAL OF SMALL ANIMAL PRACTICE, Issue 4 2002E. Scanziani Two hundred and forty-five dogs were examined serologically for the presence of antibodies against different serovars of Leptospira interrogans. The dogs belonged to five different groups: group 1 was composed of clinically healthy pet dogs referred for a regular veterinary check-up visit or for vaccination; group 2 was composed of stray dogs; and groups 3, 4 and 5 were composed of dogs maintained in three different kennels which had varying standards of hygiene. Seventy-two out of the 245 dogs examined were seropositive for leptospirosis. In group 1, there were 3·4 per cent seropositive dogs; in group 2, 30·3 per cent; in group 3, 13·8 per cent; in group 4, 38·6 per cent; and in group 5, 49·2 per cent. This study demonstrates that leptospiral infection is common in dogs housed in kennels, despite most of them being vaccinated, and that crowding of animals into unsanitary quarters is associated with a high prevalence of infection. The most common infecting serovars found were bratislava and grippotyphosa, confirming recent observations that demonstrate a significant change in the epidemiology of canine leptospirosis. [source] Serological survey for Ehrlichia canis in urban dogs from the major population centres of northern AustraliaAUSTRALIAN VETERINARY JOURNAL, Issue 8 2001RJ MASON Objective To detect evidence of Ehrlichia canis infection of dogs from the major population centres of northern Australia, if present. Design Serological investigation for E canis. Procedure The sera of 316 domestic dogs, collected from the northern Australian population centres of Townsville, Cairns, Darwin, Kununurra and Broome from May 1997 to August 1999, were investigated for evidence of infection with E canis. Samples were tested for antibodies to E canis using an indirect fluorescent antibody (IFA) test. The buffy coats from blood of dogs whose serum reacted in the IFA test were subsequently tested with a nested PCR to detect E canis DNA. When available, blood from these dogs was injected into suckling mice, which were then examined for clinical disease and tested for the presence of E canis antibodies. Results Of the 316 samples tested seven reacted in the IFA test for E canis. None of the dogs from which these samples were obtained exhibited clinical signs of acute or chronic ehrlichiosis. The six positive samples available for testing were negative when tested with the nested PCR. Suckling mice inoculated with blood from three of the dogs whose serum was positive by IFA test showed no signs of clinical disease nor did their give positive reactions in the IFA test. Conclusions No evidence of E canis infection was confirmed in any of the dogs examined. Northern Australia would appear to remain free of this obligate parasite. [source] Occurrence and distribution of Raspberry bushy dwarf virus in commercial Rubus plantations in England and WalesPLANT PATHOLOGY, Issue 6 2001D. J. Barbara Serological surveys for Raspberry bushy dwarf virus (RBDV) made between 1995 and 1997 and covering ,,10% of the commercial farms growing Rubus (red raspberry and hybrid berries) in England and Wales showed that this virus was present on approximately one-quarter of all farms and in approximately one-sixth of all plots tested. RBDV was found in all of the four main raspberry cultivars being grown at that time (Autumn Bliss, Glen Moy, Glen Prosen and Leo), in Loganberry and in Tayberry. Fifteen RBDV genotypes (including two that appeared to be mixed) were identified using RT-PCR/RFLPs, but the majority of genotypes were found only rarely. Of the RBDV isolates tested, two genotypes each comprised 12·5% and another 46·4%. None of the three most common genotypes was associated solely with single Rubus cultivars and vice versa. It is suggested that two separate outbreaks of RBDV are occurring in England and Wales. One outbreak comprises the most frequent genotype combined with one of the moderately frequent genotypes; this outbreak is largely confined to the main growing areas and is either spreading between farms or coming from multiple local sources. Circumstantial evidence suggests that these isolates (and hence this first outbreak) are of the RB pathotype. The second outbreak consists of the other moderately frequent genotype and those genotypes which are less common. These genotypes appear to be more scattered across England and Wales and seem more likely to be coming from local sources and not to be spreading naturally between commercial farms. [source] Estimating herd-specific force of infection by using random-effects models for clustered binary data and monotone fractional polynomialsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 5 2006Christel Faes Summary., In veterinary epidemiology, we are often confronted with hierarchical or clustered data. Typically animals are grouped within herds, and consequently we cannot ignore the possibility of animals within herds being more alike than between herds. Based on a serological survey of bovine herpes virus type 1 in cattle, we describe a method for the estimation of herd-specific rates at which susceptible animals acquire the infection at different ages. In contrast with the population-averaged force of infection, this method allows us to model the herd-specific force of infection, allowing investigation of the variability between herds. A random-effects approach is used to account for the correlation in the data, allowing us to study both population-averaged and herd-specific force of infection. In contrast, generalized estimating equations can be used when interest is only in the population-averaged force of infection. Further, a flexible predictor model is needed to describe the dependence of covariates appropriately. Fractional polynomials as proposed by Royston and Altman offer such flexibility. However, the flexibility of this model should be restricted, since only positive forces of infection have a meaningful interpretation. [source] Markers of hepatitis B virus infection and immunity in Victoria, Australia, 1995 to 2005AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 1 2010Benjamin Cowie Abstract Objective: Estimating the prevalence of chronic hepatitis B virus (HBV) infection in generally low-prevalence populations containing communities with a higher disease burden is difficult. This study was conducted to estimate the prevalence of serological markers of infection with, and immunity to, HBV in the Victorian population and to analyse trends in these estimates over time. Methods: A serological survey of 3,212 samples of convenience collected in the years 1995, 2000 and 2005 was conducted using a selection procedure designed to reduce selection bias. All samples were tested for hepatitis B surface and core antibodies; all core antibody positive samples (indicating previous infection) were then tested for the presence of hepatitis B surface antigen (HBsAg). Results: HBsAg prevalence was 1.1% (95%CI 0.8-1.6%) with significant differences observed by area of residence, age, gender and test year. Serological evidence of immunisation in infants and adolescents were lower than established estimates following the introduction of universal vaccination for these groups. Conclusions: This study emphasises the significant and growing problem of chronic HBV infection in Victoria and suggests lower than expected population immunity deriving from universal vaccination programs. Implications: Greater efforts are needed to formulate a comprehensive public health response to address this relatively neglected blood borne viral infection, the burden of which is very significant in some marginalised sections of our community. Increased attention to improving the universality of our immunisation programs is also needed. [source] Assessment of the potential of dogs and cats as urban reservoirs of Ross River and Barmah Forest virusesAUSTRALIAN VETERINARY JOURNAL, Issue 1-2 2002AM BOYD Objective To determine whether dogs and cats are potential reservoirs of Ross River (RR) and Barmah Forest (BF) viruses Method Young seronegative female dogs and cats were experimentally exposed to the viruses using Ochlerotatus vigilax(Skuse) mosquitoes. Results Only one of the 10 dogs and one of the 10 cats exposed to RR developed neutralising antibody. None of the animals developed detectable viraemia or clinical signs. One dog and three cats exposed to BF developed neutralising antibody. In addition, a serological survey of sera obtained from domestic dogs and cats residing in the Brisbane region indicated that 23.7% and 1.3% of dogs, and 14% and 2% of cats, had neutralising antibodies to RR and BF respectively. Conclusions Although dogs and cats are exposed naturally to these viruses, and can become infected, they are unlikely to be important urban reservoirs of either virus. [source] Assessment of the potential of dogs and cats as urban reservoirs of Ross River and Barmah Forest virusesAUSTRALIAN VETERINARY JOURNAL, Issue 1 2002AM BOYD Objective To determine whether dogs and cats are potential reservoirs of Ross River (RR) and Barmah Forest (BF) viruses Method Young seronegative female dogs and cats were experimentally exposed to the viruses using Ochlerotatus vigilax(Skuse) mosquitoes. Results Only one of the 10 dogs and one of the 10 cats exposed to RR developed neutralising antibody. None of the animals developed detectable viraemia or clinical signs. One dog and three cats exposed to BF developed neutralising antibody. In addition, a serological survey of sera obtained from domestic dogs and cats residing in the Brisbane region indicated that 23.7% and 1.3% of dogs, and 14% and 2% of cats, had neutralising antibodies to RR and BF respectively. Conclusions Although dogs and cats are exposed naturally to these viruses, and can become infected, they are unlikely to be important urban reservoirs of either virus. [source] The Conservation Relevance of Epidemiological Research into Carnivore Viral Diseases in the SerengetiCONSERVATION BIOLOGY, Issue 3 2007SARAH CLEAVELAND conservación de carnívoros; investigación epidemiológica; moquillo; rabia; Serengeti Abstract:,Recent outbreaks of rabies and canine distemper in wildlife populations of the Serengeti show that infectious disease constitutes a significant cause of mortality that can result in regional extirpation of endangered species even within large, well-protected areas. Nevertheless, effective management of an infectious disease depends critically on understanding the epidemiological dynamics of the causative pathogen. Pathogens with short infection cycles cannot persist in small populations in the absence of a more permanent reservoir of infection. Development of appropriate interventions requires detailed data on transmission pathways between reservoirs and wildlife populations of conservation concern. Relevant data can be derived from long-term population monitoring, epidemic and case-surveillance patterns, genetic analyses of rapidly evolving pathogens, serological surveys, and intervention studies. We examined studies of carnivore diseases in the Serengeti. Epidemiological research contributes to wildlife conservation policy in terms of management of endangered populations and the integration of wildlife conservation with public health interventions. Long-term, integrative, cross-species research is essential for formulation of effective policy for disease control and optimization of ecosystem health. Resumen:,Brotes recientes de rabia y moquillo en poblaciones silvestres del Serengeti muestran que las enfermedades infecciosas constituyen una causa significativa de mortandad que puede resultar en la extirpación regional de especies en peligro, aun en áreas extensas bien protegidas. Sin embargo, el manejo efectivo de una enfermedad infecciosa depende críticamente del entendimiento de la dinámica epidemiológica del patógeno. Los patógenos con ciclo infeccioso corto no pueden persistir en poblaciones pequeñas en ausencia de un reservorio de la infección más permanente. El desarrollo de intervenciones adecuadas requiere de datos detallados de las vías de transmisión entre reservorios y poblaciones de vida silvestre de preocupación para la conservación. Se pueden derivar datos importantes del monitoreo de poblaciones a largo plazo, de patrones de epidemias y de estudios de caso, del análisis genético de patógenos que evolucionan rápidamente, de muestreos sexológicos y de estudios de intervención. Examinamos estudios de enfermedades de carnívoros en el Serengeti. La investigación epidemiológica contribuye a las políticas de conservación de vida silvestre en términos de la gestión de poblaciones en peligro y de la integración de la conservación con intervenciones de salud pública. La investigación a largo plazo e integradora es esencial para la formulación de políticas efectivas para el control de enfermedades y la optimización de la salud del ecosistema. [source] Prevalence of antibodies to Leptospira serovars in beef cattle in central QueenslandAUSTRALIAN VETERINARY JOURNAL, Issue 5 2001PF BLACK Objective To obtain up-to-date data on the prevalence of antibodies to Leptospiraserovars in central Queensland beef herds preliminary to assessing their role in bovine subfertility and the role of cattle as a zoonotic reservoir. Design Sera from 2857 female cattle in 68 central Queensland beef herds were tested for antibodies to 14 Leptospiraserovars using the microscopic agglutination test. Vaccination use and age of cattle were collected to enable the calculation of crude and age-stratified seroprevalences. Results The most commonly detected antibodies were to serovars hardjo (15.8% crude seroprevalence), tarassovi (13.9%), pomona (4.0%) and szwajizak (2.2%). Vaccinates were omitted from the hardjo and pomona seroprevalence data. The seroprevalence for hardjo and pomona tended to increase with age of the animals. Conclusion These results are broadly similar to those of previous serological surveys. The data suggest that serovars other than hardjo, pomona and tarassovi, are unlikely to have a significant role in bovine subfertility and that cattle are unlikely to be a source of human infection with them in central Queensland. [source] Epidemiology and control of Menangle virus in pigsAUSTRALIAN VETERINARY JOURNAL, Issue 3 2001PD KIRKLAND Objective To describe the epidemiology and eradication of Menangle virus infection in pigs. Design Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. Procedure Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. Results Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (A 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalusfrom two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. Conclusions Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups. [source] Measures of Disassortativeness and their Application to Directly Transmitted InfectionsBIOMETRICAL JOURNAL, Issue 3 2009C. P. Farrington Abstract We propose a measure of disassortativeness to summarize contact patterns relevant to the transmission of directly transmitted infections. We discuss the properties of this measure, describe standardization relative to homogeneous mixing, and generalize it to multivariate contact structures. We explore some of its properties and apply our methods to serological surveys of close contact infections and surveys of self-reported social contacts obtained in several European countries. [source] | ||||||||||||||||