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Were Polish wild boars exposed to Schmallenberg virus?
2017
Kęsik-Maliszewska, Julia | Jabłoński, Artur | Larska, Magdalena
Introduction: A novel to Europe Schmallenberg virus (SBV) causes clinical disease manifested by reproduction disorders in farm ruminants. In free-living ruminants, SBV antibodies as well as the virus were detected. Recent studies also revealed SBV antibodies in wild boars. The study investigates SBV antibodies occurring in wild boars in Poland at the peak of recent virus epidemics in the country.Material and Methods: Samples collected from 203 wild boars culled during the 2012/2013 and 2013/2014 hunting season were serologically tested using multi-species cELISA. Attempted neutralisation tests failed due to poor serum quality. RT-PCR was implemented in seropositive and doubtful animals.Results: Two samples collected from wild boar in the winter of 2013 gave a positive result in ELISA, while another two from the 2012/2013 hunting season were doubtful. No SBV RNA was detected in spleen and liver tissues.Conclusion: Low SBV seroprevalence in wild boars, despite high incidence of SBV infections occurring simultaneously in wild ruminants, suggests that boars are unlikely to be a significant reservoir of the virus in the sylvatic environment in Poland.
Показать больше [+] Меньше [-]Current status of porcine epidemic diarrhoea (PED) in European pigs
2019
Porcine epidemic diarrhoea (PED) is a highly contagious and devastating enteric disease of pigs caused by porcine epidemic diarrhoea virus (PEDV), an enveloped, single-stranded RNA virus belonging to the Alphacoronavirus genus of the Coronaviridae family. The disease is clinically similar to other forms of porcine gastroenteritis. Pigs are the only known host of the disease, and the occurrence of PED in wild boars is unknown. The virus causes acute diarrhoea, vomiting, dehydration, and high mortality in suckling piglets reaching 100%. Heavy economic losses in the pig-farming industry were sustained in the USA between 2013 and 2015 when PEDV spread very quickly and resulted in epidemics. The loss in the US pig industry has been estimated at almost seven million pigs. The purpose of this review is a description of the current status of porcine epidemic diarrhoea in European pigs and the risk presented by the introduction of PEDV to Poland in comparison to the epidemics in the USA.
Показать больше [+] Меньше [-]Comparative expression analysis of inflammatory and immune-related genes in cattle during acute infection with foot-and-mouth disease virus in Egypt
2021
El Nahas, Abeer F. | Abd El Naby, Walaa S.H. | Khatab, Shymaa A. | Fergany, Al-Zahraa A. | Rashed, Rashed R.
Foot-and-mouth disease is a highly infectious viral disease affecting all cloven-footed domestic animals. The three foot-and-mouth disease virus (FMDV) serotypes A, O and SAT2 are at present the greatest threat to susceptible animals in Egypt. The aim of the present study was, for the host factors associated with different FMDV infections in cattle during the acute phase, to compare these factors’ influence on the expression of the IL-10, TLR-2, TNF-α, CXCL10, CD48, NFATC4 and IFNG inflammatory and immune-related genes. Vesicular fluid and epithelium samples were obtained from at least three infected cattle on the same affected farm during three different FMDV outbreaks and were used for serotyping of the virus and for expression analysis of host genes. A two-step RT-PCR was used for diagnosis of the virus with primers specific for each serotype. In quantitative PCR analysis, the expression patterns of TLR-2 and IFNG were prominent, while NFATC4 expression was absent in all FMDV-infected cattle. The highest expression of CD48 was associated with increased expression of other inflammatory and immune-related genes (IL-10, TLR-2, TNF-α and IFNG), which may be an indication of rapid virus clearance. The use of vesicular fluid and epithelium for investigation of viral and immune-related gene expression levels in acute FMDV infection is possible. Host-dependent variation in the expression of the studied genes was observed in different FMDV serotype outbreaks.
Показать больше [+] Меньше [-]Development of a new RT-PCR with multiple primers for detecting Southern African Territories foot-and-mouth disease viruses
2018
Liu, Yali | Ding, Yao-Zhong | Dai, Jun-Fei | Ma, Bing | He, Ji-Jun | Ma, Wei-Min | Lv, Jian-Liang | Ma, Xiao-Yuan | Ou, Yun-Wen | Wang, Jun | Liu, Yong-Sheng | Chang, Hui-Yun | Wang, Yong-Lu | Zhang, Qiang | Liu, Xiang-Tao | Zhang, Yong-Guang | Zhang, Jie
Introduction: The extremely high genetic variation and the continuously emerging variants of foot-and-mouth disease virus (FMDV) of Southern African Territory (SAT) serotypes including SAT1, SAT2, and SAT3 make it necessary to develop a new RT-PCR for general use for monitoring viruses based on the updated genome information. Material and Methods: A FMDV SAT-D8 one-step RT-PCR was established based on the 1D2A2B genes of the SAT serotype viruses with a multiplex primer set. FMDV A, O, C, and Asia 1 serotypes, other vesicular disease viruses, inactivated SAT viruses, and 125 bovine, ovine, caprine and porcine tissue samples collected from the Chinese mainland were included for evaluating the assay. Results: The new RT-PCR was proven to be specific without cross-reactions with Eurasian FMDV, swine vesicular disease virus (SVDV), Seneca valley virus (SVV), or other common viral pathogens of cattle, sheep, goat, and pig. An around 257 bp-sized amplicon clearly appeared when the inactivated SAT viruses were detected. However, all 125 samples collected from FMDV-susceptible animals from the Chinese mainland which has not known SAT epidemics showed negative results. Conclusions: A FMDV SAT-D8 one-step RT-PCR is a promising method for primary screening for FMDV SAT serotypes.
Показать больше [+] Меньше [-]Characterization of the temporal and spatial distribution and reproductive ratio of vesicular stomatitis outbreaks in Mexico in 2008
2011
Arroyo, Montserrat | Perez, Andres M. | Rodriguez, Luis L.
Objective--To characterize the temporal and spatial distribution and reproductive ratio of vesicular stomatitis (VS) outbreaks reported in Mexico in 2008. Procedures--The Poisson model of the space-time scan statistic was used to identify periods and geographical locations at highest risk for VS in Mexico in 2008. The herd reproductive ratio (Rh) of the epidemic was computed by use of the doubling-time method. Results--1 significant space-time cluster of VS was detected in the state of Michoacan from September 4 through December 10, 2008. The temporal extent of the VS outbreaks and the value and pattern of decrease of the Rh were different in the endemic zone of Tabasco and Chiapas, compared with findings in the region included in the space-time cluster. Conclusions and Clinical Relevance--The large number of VS outbreaks reported in Mexico in 2008 was associated with the spread of the disease from the endemic zone in southern Mexico to areas sporadically affected by the disease. Results suggested that implementation of a surveillance system in the endemic zone of Mexico aimed at early detection of changes in the value of Rh and space-time clustering of the disease could help predict occurrence of future VS outbreaks originating from this endemic zone. This information will help prevent VS spread into regions of Mexico and neighboring countries that are only sporadically affected by the disease.
Показать больше [+] Меньше [-]Epidemiologic investigation of a silage-associated epizootic of ovine listeric encephalitis, using a new Listeria-selective enumeration medium and phage typing
1992
Vazquez-Boland, J.A. | Dominguez, L. | Blanco, M. | Rocourt, J. | Fernandez-Garyzabal, J.F. | Gutierrez, C.B. | Tascon, R.I. | Rodriguez-Ferri, E.F.
The role of silage feeding in the origin of an epizootic of encephalitic listeriosis in a sheep flock was investigated by use of a new direct Listeria-selective isolation and enumeration medium, in combination with serotyping and phage typing. The silage contained high numbers (about 10(6) cells/g) of a L monocytogenes strain indistinguishable with respect to serovar and phagovar from that isolated from the brains of sick sheep. These results provided unambiguous bacteriologic evidence of the epidemiologic link between silage consumption and listeriosis in ruminants.
Показать больше [+] Меньше [-]Field evaluation of a commercial M-protein vaccine against Streptococcus equi infection in foals
1991
Hoffman, A.M. | Staempfli, H.R. | Prescott, J.F. | Viel, L.
A double-blind randomized clinical trial was undertaken to determine the value of parenterally administered Streptococcus equi M-protein vaccine in foals during an epizootic of strangles. Weaned mixed-breed foals (n = 664) housed on 2 adjacent feed-lots (A and B) arrived over a 5-day period, 2 weeks before primary vaccination. Foals in lot B (n = 114) were randomly administered vaccine (n = 59) or saline solution (placebo; n = 55) on 3 occasions at biweekly intervals. Foals in lot A (n = 450) were given 1 dose of vaccine (n = 225) or placebo. The following clinical observations were scored blindly by a single observer for all foals in lot B and for 120 (randomly sampled) foals in lot A on a single day, 2 (lot B) and 6 (lot A) weeks after final vaccination: cervical lymphadenopathy, type of bilateral nasal discharge, and palpable swelling at injection site(s). Bacteriologic culture of nasal swab specimens or lymph node aspirates from selected foals with clinical disease yielded S equi. Cervical lymphadenopathy was observed in 17 of 59 (29%) vaccinates and 39 of 55 (71%) nonvaccinated controls in lot B and in 32 of 60 (53%) vaccinates and 29 of 60 (48%) controls in lot A. Contingency X2 analysis confirmed significantly lower cervical lymphadenopathy rate (X2 = 18.5; P < 0.001) and prevalence of mucopurulent nasal discharge (X2 = 11.4; P < 0.01) for vaccinates in lot B only. Swelling(s) at the vaccine injection site were palpated in 44% of lot B and 29% of lot A vaccinates vs < 2% of placebo controls. In the face of intense natural exposure, foals inoculated 3 times with M-protein vaccine were less than half as likely to have clinical signs of strangles as were nonvaccinated horses.
Показать больше [+] Меньше [-]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.
Показать больше [+] Меньше [-]Molecular epidemiology of Pasteurella multocida in turkeys
1991
Carpenter, T.E. | Snipes, K.P. | Kasten, R.W. | Hird, D.W. | Hirsh, D.C.
Pasteurella multocida isolated from turkeys during an outbreak of fowl cholera was characterized by serotype and heterogeneity of genes encoding rRNA (ribotype) to investigate the epidemiology of the organism. Isolates were collected between October 1985 and July 1986. The M9 or Clemson University fowl cholera vaccine-like strain was detected in 17% of the flocks with fowl cholera. One particular strain, isolated only from breeder flocks, was recovered from 7 of the 10 breeder flocks examined in this study. Intracompany transmission appeared to be common, implying a failure in biosecurity. Circumstantial evidence indicated that in the field, the incubation period of P multocida in a turkey flock may be between 2 to 7 weeks. Wildlife did not appear to be an important reservoir of P multocida for turkeys during this study period. Ribotyping results tended to discount several of the possible interflock transmissions, as suggested by examination of serotyping results alone; however, serotyping in combination with ribotyping proved helpful in understanding the epidemiology of P multocida in turkeys.
Показать больше [+] Меньше [-]Acute porcine reproductive and respiratory syndrome outbreaks in immunized sow herds: from occurrence to stabilization under whole herd vaccination strategy
2018
Moon, S.H., Konkuk University, Seoul, Republic of Korea | Yoo, S.J., Konkuk University, Seoul, Republic of Korea | Noh, S.H., Konkuk University, Seoul, Republic of Korea | Kwon, T., Konkuk University, Seoul, Republic of Korea | Lee, D.U., Konkuk University, Seoul, Republic of Korea | Je, S.H., Konkuk University, Seoul, Republic of Korea | Kim, M.H., Konkuk University, Seoul, Republic of Korea | Seo, S.W., Konkuk University, Seoul, Republic of Korea | Lyoo, Y.S., Konkuk University, Seoul, Republic of Korea
Outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated sow herds from occurrence to stabilization were monitored and analyzed in terms of serology and reproductive performance. Three different conventional pig farms experienced severe reproductive failures with the introduction of a type 1 PRRSV. These farms had adopted mass vaccination of sows using a type 2 PRRSV modified live vaccine (MLV). Therefore, to control the type 1 PRRSV, an alternative vaccination program utilizing both type 1 and type 2 MLV was undertaken. Following whole herd vaccinations with both types of MLV, successful stabilization of PRRS outbreaks was identified based on serological data (no viremia and downward trends in ELISA antibody titers in both sows and suckling piglets) and recovery of reproductive performance. Additionally, through comparison of the reproductive parameters between outbreak and non-outbreak periods, it was identified that PRRSV significantly affected the farrowing rate and the number of suckling piglets per litter at all three pig farms. Comparison of reproductive parameters between periods when the different vaccination strategies were applied revealed that the number of piglets born in total and born dead per litter were significantly increased after the introduction of the type 1 PRRS MLV.
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