Genomic and antigenic characterization of a cytopathic bovine viral diarrhea virus 1i isolated in the United States.

Bovine viral diarrhea viruses (BVDV) are a common global viral pathogen of ruminants. Considerable genetic variability is found amongst BVDV1 isolates, with at least 21 subgenotypes being described. In the United States, BVDV1a and 1b are the only subgenotypes described to date.

A Tool for Assessment of Animal Health Laboratory Safety and Biosecurity: The Safety Module of the Food and Agriculture Organization's Laboratory Mapping Tool.

The Laboratory Management Tool (LMT) is a standardized spreadsheet-based assessment tool developed to help support national, regional, and global efforts to maintain an effective network of animal health and veterinary public health laboratories. The safety and biosecurity module of the LMT (LMT-S) includes 98 measures covering administrative, operational, engineering, and personal protective equipment practices used to provide laboratory safety and biosecurity. Performance aspects of laboratory infrastructure and technical compliance considered fundamental for ensuring that a laboratory is able to appropriately function in a safe and biosecure manner are systematically queried and scored for compliance on a four-point scale providing for a semi-quantitative assessment.

Evaluation of Fast Technology Analysis (FTA) Cards as an improved method for specimen collection and shipment targeting viruses associated with Bovine Respiratory Disease Complex.

In order to improve the analytic quality of respiratory specimens collected from cattle for nucleic acid-based diagnosis, a study was undertaken to verify realtime PCR efficiency of specimens collected and stabilized on FTA Cards™, filter paper which is treated chemically. Nucleic acids collected using FTA Cards without the need for a cold-chain or special liquid media handling provided realtime PCR results consistent (96.8% agreement, kappa 0.

Evaluation of enzyme-linked immunosorbent assays performed on milk and serum samples for detection of neosporosis and leukosis in lactating dairy cows.

Serum and milk samples from 1229 cows on 22 Ontario dairy farms were individually tested for antibodies specific for bovine leukosis virus (BLV) and Neospora caninum by enzyme-linked immunosorbent assay (ELISA). Antibodies against BLV were present in 361 serum samples (29.4%) and 369 milk samples (30.

Identification and characterization of a novel alpaca respiratory coronavirus most closely related to the human coronavirus 229E.

In 2007, a novel coronavirus associated with an acute respiratory disease in alpacas (Alpaca Coronavirus, ACoV) was isolated. Full-length genomic sequencing of the ACoV demonstrated the genome to be consistent with other Alphacoronaviruses. A putative additional open-reading frame was identified between the nucleocapsid gene and 3'UTR.

Pandemic (H1N1) 2009 in captive cheetah.

We describe virus isolation, full genome sequence analysis, and clinical pathology in ferrets experimentally inoculated with pandemic (H1N1) 2009 virus recovered from a clinically ill captive cheetah that had minimal human contact. Evidence of reverse zoonotic transmission by fomites underscores the substantial animal and human health implications of this virus.

Variation in Bluetongue virus real-time reverse transcription polymerase chain reaction assay results in blood samples of sheep, cattle, and alpaca.

Bluetongue is a vector-borne viral disease that affects domestic and wild ruminants. The epidemiology of this disease has recently changed, with occurrence in new geographic areas. Various real-time quantitative reverse transcription polymerase chain reaction (real-time qRT-PCR) assays are used to detect Bluetongue virus (BTV); however, the impact of biologic differences between New World camelids and domestic ruminant samples on PCR efficiency, for which the BTV real-time qRT-PCR was initially validated are unknown.

Effect of changes in testing parameters on the cost-effectiveness of two pooled test methods to classify infection status of animals in a herd.

Monte Carlo simulation was used to determine optimal fecal pool sizes for identification of all Mycobacterium avium subsp. paratuberculosis (MAP)-infected cows in a dairy herd. Two pooling protocols were compared: a halving protocol involving a single retest of negative pools followed by halving of positive pools and a simple protocol involving single retest of negative pools but no halving of positive pools.

Characteristics of a very virulent infectious bursal disease virus from California.

An outbreak of infectious bursal disease (IBD) in two California layer flocks resulted in the isolation of two infectious bursal disease viruses designated rA and rB. Increased mortality plus gross and histopathology in the layer flocks suggested rA and rB could be very virulent infectious bursal disease virus (vvIBDV). Preliminary studies indicated that high mortality resulted when bursa homogenates from the layer farms were used to inoculate specific-pathogen-free (SPF) chicks.

An outbreak of late-term abortions, premature births, and congenital deformities associated with a bovine viral diarrhea virus 1 subtype b that induces thrombocytopenia.

Bovine viral diarrhea virus 1 (BVDV-1) subtype b was isolated from premature Holstein calves from a dairy herd that experienced an outbreak of premature births, late-term abortions, brachygnathism, growth retardation, malformations of the brain and cranium, and rare extracranial skeletal malformations in calves born to first-calf heifers. Experimental inoculation of 3 colostrum-deprived calves aged 2-4 months old with this BVDV isolate resulted in thrombocytopenia, lymphopenia, and leukopenia. Outbreaks of brachygnathism are rarely associated with BVDV, and thrombocytopenia is rarely associated with BVDV-1 strains.

Evaluation of the Western immunoblot as a detection method for Brucella abortus exposure in elk.

Brucella abortus has been an important wildlife disease issue for most of the last century, especially because wildlife species are considered to be important disease reservoirs for cattle. Diagnostic uncertainty, caused in part by cross-reactions of antibodies to environmental pathogens such as Yersinia enterocolitica O:9 on standard Brucella serology, has exacerbated the challenges of managing the disease and has highlighted the need for test validation in wildlife species. The western immunoblot was evaluated for use in detecting B.

Multiplexed molecular assay for rapid exclusion of foot-and-mouth disease.

A nucleic acid-based multiplexed assay was developed that combines detection of foot-and-mouth disease virus (FMDV) with rule-out assays for two other foreign animal diseases and four domestic animal diseases that cause vesicular or ulcerative lesions indistinguishable from FMDV infection in cattle, sheep and swine. The FMDV "look-alike" diagnostic assay panel contains 5 PCR and 12 reverse transcriptase PCR (RT-PCR) signatures for a total of 17 simultaneous PCR amplifications for 7 diseases plus incorporating 4 internal assay controls. It was developed and optimized to amplify both DNA and RNA viruses simultaneously in a single tube and employs Luminex liquid array technology.

Conventional and future diagnostics for avian influenza.

The significant and continued transboundary spread of Asian avian influenza H5N1 since 2003, paired with documented transmission from avian species to humans and other mammals, has focused global attention on avian influenza virus detection and diagnostic strategies. While the historic and conventional laboratory methods used for isolation and identification of the virus and for detection of specific antibodies continued to be widely applied, new and emerging technologies are rapidly being adapted to support avian influenza virus surveillance and diagnosis worldwide. Molecular tools in particular are advancing toward lab-on-chip and fully integrated technologies that are capable of same day detection, pathotyping, and phylogenetic characterization of influenza A viruses obtained from clinical specimens.

Inability of real-time reverse transcriptase PCR assay to detect subtype H7 avian influenza viruses isolated from wild birds.

We report a failure of the real-time reverse transcriptase PCR H7 subtyping protocol currently used in national avian influenza surveillance programs. Significant substitutions in primer and probe target sequences were identified, especially in wild bird viruses. The protocol, originally designed for detecting H7 influenza viruses in poultry, is not reliable for wild bird surveillance.

Cyclical changes in seroprevalence of leptospirosis in California sea lions: endemic and epidemic disease in one host species?

Background: Leptospirosis is a zoonotic disease infecting a broad range of mammalian hosts, and is re-emerging globally. California sea lions (Zalophus californianus) have experienced recurrent outbreaks of leptospirosis since 1970, but it is unknown whether the pathogen persists in the sea lion population or is introduced repeatedly from external reservoirs.

Methods: We analyzed serum samples collected over an 11-year period from 1344 California sea lions that stranded alive on the California coast, using the microscopic agglutination test (MAT) for antibodies to Leptospira interrogans serovar Pomona.

Impact of Corynebacterium pseudotuberculosis infection on serologic surveillance for Johne's disease in goats.

False-positive results on serologic assays for Mycobacterium avium subsp. paratuberculosis (MAP) are believed to occur due to cross-reacting antibody produced by Corynebacterium pseudotuberculosis (C. pstb) infection in goats.

Prevalence of Neospora caninum and persistent infection with bovine viral diarrhea virus in dairy-breed steers in a feedlot.

Objective: To determine the prevalence and effect of Neospora caninum infection and persistent infection (PI) with bovine viral diarrhea virus (BVDV) on weight gain, morbidity, and mortality rate in dairy-breed steer calves located on a feedlot in California.

Design: Prospective cohort observational study.

Animals: 900 dairy-breed steer calves in 2 pens.

Use of sentinel chickens to evaluate the effectiveness of cleaning and disinfection procedures in noncommercial poultry operations infected with exotic Newcastle disease virus.

The use of sentinel chickens in establishing the negative status of commercial poultry flocks depopulated due to exotic Newcastle disease (END) is considered to be an economically beneficial process. However, the costs and benefits of using sentinel chickens in noncommercial operations are in question. The objective of this study was to use sentinel chickens to evaluate whether adequate cleaning and disinfection coupled with an appropriate time period without susceptible poultry species on the premises would eliminate END virus from a noncommercial poultry operation and preclude the need for placement of sentinels in previously infected operations before declaring them free of virus.

Neospora caninum and Leptospira serovar serostatus in dairy cattle in Ontario.

No significant association existed between Neospora caninum titer and serostatus to Leptospira serovar hardjo, icterohaemorrhagiae, or pomona in cattle on 78 dairy herds in Ontario. Leptospira titer increased with parity. Amongst herds not vaccinated against Leptospira, the proportions of herds with > or = 1 animal seropositive to serovar hardjo, icterohaemorrhagiae, or pomona were 45%, 42%, and 58%, respectively.

Factors affecting sensitivity and specificity of pooled-sample testing for diagnosis of low prevalence infections.

Testing of pooled samples has been proposed as a low-cost alternative for diagnostic screening and surveillance for infectious agents in situations where the prevalence of infection is low and most samples can be expected to test negative. The present study extends our previous work in pooled-sample testing (PST) to evaluate effects of the following factors on the overall PST sensitivity (SE(k)) and specificity (SP(k)): dilution (pool size), cross-contamination, and cross-reaction. A probabilistic model, in conjunction with Monte Carlo simulations, was used to calculate SE(k) and SP(k), as applied to detection of bovine viral diarrhea virus (BVDV) persistently infected (PI) animals using RT-PCR.

Avian influenza A virus subtype H5N2 in a red-lored Amazon parrot.

Case Description: A 3-month-old red-lored Amazon parrot (Amazona autumnalis autumnalis) was evaluated for severe lethargy.

Clinical Findings: Avian influenza virus hemagglutinin subtype H5N2 with low pathogenicity was characterized by virus isolation, real-time reverse transcriptase PCR assay, chicken intravenous pathogenicity index, and reference sera. The virus was also determined to be closely related to a virus lineage that had been reported only in Mexico and Central America.

Environmental air sampling to detect exotic Newcastle disease virus in two California commercial poultry flocks.

The 2002--2003 Exotic Newcastle Disease (END) outbreak in Southern California poultry provided an opportunity to evaluate environmental air sampling as an efficient and cost-effective means of sampling flocks for detection of a circulating virus. Exotic Newcastle Disease virus was detected by real-time reverse transcriptase PCR from air samples collected using a wetted-wall cyclone-style air sampler placed within 2 m of birds in 2 commercial flocks suspected of being naturally exposed to END virus during the outbreak. Exotic Newcastle Disease virus was detected after 2 hours of air sampling the poultry-house environments of the 2 naturally infected flocks.

High-throughput real-time RT-PCR assay to detect the exotic Newcastle Disease Virus during the California 2002--2003 outbreak.

During the 2002--2003 Exotic Newcastle Disease (END) outbreak in Southern California, a high-throughput real-time reverse transcriptase-polymerase chain reaction (RRT-PCR) system was developed to respond to the large diagnostic and surveillance sample workload. A 96-well RNA extraction method, using magnetic bead technology, combined with a 96-well RRT-PCR assay, allowed 1 technician to process and test more than 400 samples per day. A 3-technician team could complete testing on approximately 1,900 samples per day.