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Reproductive tract disease associated with inoculation of pregnant white-tailed deer with bovine viral diarrhea virus
2008
Ridpath, Julia F. | Driskell, Elizabeth A. | Chase, Christopher C.L. | Neill, John D. | Palmer, Mitchell V. | Brodersen, Bruce W.
Objective-To inoculate white-tailed deer (Odocoileus virginianus) during the sixth or seventh week of gestation with bovine viral diarrhea virus (BVDV) and observe for signs of reproductive tract disease during a 182-day period. Animals-10 pregnant white-tailed deer (8 seronegative and 2 seropositive [control deer] for BVDV). Procedures-Deer were inoculated with 1 of 2 deer-derived BVDV strains (RO3-20663 or RO3-24272). Serum anti-BVDV antibody titers were determined prior to and 21 or 35 days after inoculation. Virus isolation (VI) procedures were performed on tissues from fetuses and does that died and on blood samples collected from live fawns. Ear notch specimens obtained from live fawns were assessed by use of BVDV antigen-capture ELISA (ACE). Results-Both RO3-20663-inoculated seropositive deer gave birth to apparently normal fawns. Among the RO3-24272-inoculated seronegative deer, 1 died, and 1 aborted and 1 resorbed their fetuses; among the RO3-20663-inoculated seronegative deer, 3 died, 1 aborted its fetus, and 1 gave birth to 2 fawns that were likely persistently infected. On the basis of VI and ACE results, those 2 fawns were positive for BVDV; both had no detectable neutralizing anti-BVDV antibodies in serum. Conclusions and Clinical Relevance-Reproductive tract disease that developed in pregnant white-tailed deer following BVDV inoculation was similar to that which develops in BVDV-exposed cattle. Methods developed for BVDV detection in cattle (VI, immunohistochemical evaluations, and ACE) can be applied in assessments of white-tailed deer. Fawns from does that had serum anti-BVDV antibodies prior to inoculation were protected against BVDV infection in utero.
显示更多 [+] 显示较少 [-]Detection of respiratory pathogens in air samples from acutely infected pigs
2008
Hermann, J.R. | Brockmeier, S.L. | Yoon, K.J. | Zimmerman, J.J.
Pathogens causing significant respiratory disease in growing pigs include Porcine reproductive and respiratory syndrome virus, Porcine circovirus 2, swine influenza virus, porcine respiratory coronavirus, Mycoplasma hyopneumoniae, and Bordetella bronchiseptica. The objective of this research was to characterize the respiratory excretion of these pathogens by acutely infected pigs. Pigs were inoculated under experimental conditions with 1 pathogen. Samples were collected from the upper respiratory tract and exhaled air. All pathogens were detected in swabs of the upper respiratory tract, but only M. hyopneumoniae and B. bronchiseptica were detected in expired air from individually sampled, acutely infected pigs. These findings suggest either that the acutely infected pigs did not aerosolize the viruses or that the quantity of virus excreted was below the detection threshold of current sampling or assay systems, or both, at the individual-pig level.
显示更多 [+] 显示较少 [-]Use of epidemiologic risk modeling to evaluate control of foot-and-mouth disease in southern Thailand
2008
Wongsathapornchai, K. | Salmān, Muḥammad | Edwards, J.R. | Morley, P.S. | Keefe, T.J. | Van Campen, H. | Weber, S. | Premashthira, S.
Objective--To assess the impacts of the introduction of foot-and-mouth disease (FMD) and various FMD control programs in southern Thailand. Animals--A native population of 562,910 cattle and 33,088 buffalo as well as 89,294 animals legally transported into southern Thailand. Procedures--A quantitative risk assessment was used to ascertain the probability of FMD introduction, and an intrinsic dynamic model was used to assess impacts. Value for the transmission rate (β) was estimated. Five scenarios created to assess the impacts of nonstructural protein (NSP) testing, mass vaccination, and culling were examined. Impacts were assessed through an examination of the estimated annual cumulative incidence (ACI) of FMD. The ACIs of various scenarios were compared by use of the Tukey Studentized range technique. Results--β was estimated at 0.115. Approximately 35,000 cases of FMD would be expected from the baseline situation. A 30% reduction of ACI was detected with the introduction of NSP antibody testing. Prophylactic vaccination resulted in an 85% reduction of ACI. Concurrent use of NSP antibody testing and vaccination reduced the ACI by 96%, and the addition of an eradication policy resulted in a slightly greater decrease in the ACI (98%). Conclusions and Clinical Relevance--The study used epidemiologic models to investigate FMD control interventions. Results suggested that vaccination has more impact than the use of NSP testing. Use of the NSP test reduced ACI during peak seasons, whereas vaccination diminished the underlying incidence. The best mitigation plan was an integrated and strategic use of multiple control techniques.
显示更多 [+] 显示较少 [-]Roles of the hypocretin/orexins in the regulation of sleep and wakefulness
2008
Terao, A.(Hokkaido Univ., Sapporo (Japan)) | Haruyama, T. | Kimura, K.
Hypocretin/orexin is produced exclusively in the dorsal and lateral hypothalamus but its projection is widespread within the brain and plays important roles. In this paper, we review the independent discoveries of the hypocretin/orexin peptides, the neuroanatomy of this system, and the link to the sleep disorder narcolepsy that has led to the idea that this system plays a crucial role in the regulation of sleep and wakefulness.
显示更多 [+] 显示较少 [-]Establishment of a laboratory colony of taiga tick Ixodes persulcatus for tick-borne pathogen transmission studies
2008
Konnai, S.(Hokkaido Univ., Sapporo (Japan)) | Saito, Y. | Nishikado, H. | Yamada, S. | Imamura, S. | Mori, A. | Ito, T. | Onuma, M. | Ohashi, K.
Ixodes persulcatus Schulze (I. persulcatus) is distributed in Russia and Far East Asia including Japan, and has been implicated as the vector of several human pathogens. In particular, I. persulcatus acts as the only tick vector for human lyme borreliosis in Japan. In order to elucidate the mechanism of transmission of I. persulcatus-borne pathogens, we developed a laboratory colony of I. persulcatus. Ticks were fed on Syrian hamster and engorged ticks that had dropped off the animals were collected and maintained to allow them to molt. Tick rearing was performed in incubator at 20degC with 95% relative humidity and 12-hour light/dark photo-period regimen. We found out that adult females fed for 8+-2 days and had a pre-oviposition period lasting for 7+-2 days. The minimum egg incubation period was 1 month with the hatched larvae feeding for 3+-1 days and molting to nymphs 3-4 months thereafter. Meanwhile, the nymphs fed for 4+-1 days and molted to adult 2-3 months thereafter. For future analysis of gene expression profiles in I. persulcatus, we cloned and sequenced the actin gene (a housekeeping gene), and found that it is 92.7% to 98.6% homologous to the published sequences of related ixodid ticks. This laboratory colony of I. persulcatus will facilitate investigations on the role of tick-derived molecules on the transmission of I. persulcatus-borne pathogens and will be important for identification of potential anti-tick vaccine and acaricide target molecules.
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