Objectives: Bovine abortion is an important cause of economic loss in dairy cattle, and has important implications in public veterinary health. Veneto region, in Northeastern Italy, has implemented since year 2006 an official surveillance plan on abortion in dairy cattle. The aim of this study is to describe the results of this surveillance, from 2006 to 2019, and to provide information about the occurrence of abortive pathogens and their prevalence. Material and methods: Aborted fetuses, accompanied by the dam’s blood sample, were delivered to the Regional State Veterinary Laboratory (IZSVe), and submitted to a panel of laboratory tests. The cows’ sera were tested for antibodies against Neospora caninum, Chlamydophila abortus, Coxiella burnetii, IBR virus, and BVD non structural protein NS2-3 by mean of commercial ELISA tests, and to Brucella abortus and melitensis following the EU regulation mandatory method. Antibody against Coxiella burnetii were detected using also the complement fixation test according to OIE guideline. On all the fetuses were performed necroscopy, microbiological culture from abomasum, histopathology from lung, and detection, by PCR from spleen, of BVD virus, Chlamydia spp., and Coxiella. burnetii. Detection of Neospora caninum by PCR from the brain was performed only on fetuses older than four month. Brucella spp isolation was carried out only if the abortion occurred after the fifth pregnancy month; while Campylobacter fetus isolation was performed on abortions occurred before the fifth month. A PCR for the detection of Schmallenberg virus from the brain was introduced after year 2013. Results: During these years (2006-2019) 4,562 bovine abortions were delivered to IZSVe, 668 of them were under the fifth month of gestation (14.6%). The most of fetuses delivered were autolytic (62.7%), without macroscopic lesions (30.8%) or mummified (4.5%). Histologically lung inflammatory lesions were present in 32.8% of cases. An infective agent was detected in 1451 fetuses (31.8%). Neospora caninum was the most frequent specific abortion agent isolated (22.2%), followed by BVD virus (5.7%), Coxiella. Burnetii (4.7%) and Chlamydia spp (0.7%). Schmallenberg virus was detected only in 3 fetuses delivered respectively in year 2012, 2013 and 2014, but only one showed congenital abnormalities (limbs arthrogryposis and jaw malformation). Microbiological culture was considered positive only when specific abortifacient pathogens were isolated: according to this criteria the 13% had a culture positive test. Among the bacteriological agents isolated the most relevant were T. pyogenes (47.4%), Bacillus spp. (29.4%), Streptococcus spp. (15.8%), L. monocytogenes and fungi (1.9%), P. multocida (1.7%), Salmonella spp. (1.1%), M. haemolytica (0.7%), Corynebacterium spp. (0.2%). Campylobacter fetus was isolated in one abortion and Brucella spp. was never isolated. Serological tests showed a high percentage of cows had antibodies against BVD virus (44.8%), Chlamydophila abortus (41.3%), Neospora caninum (33.2%); IBR virus (25.4%), C. burnetii (15.8%). All tested sera and abortions were negative for Brucella spp. The agreement between serological test and PCR for Neospora caninum was substantial (Cohen’s kappa (k) = 0.667, while the agreement for BVD virus and C. burnetii was slight (k = 0.11; k = 0.16). Conclusions: In our opinion, the abortion surveillance program provided many useful and interesting information about the health status of dairy farms and the diagnostic methods suitable for abortion diagnosis. Necroscopy findings showed the low prevalence of specific macroscopic lesion in fetuses, highlighting the importance to use a standardized protocol including tests for detection of the most relevant abortion agents. Infective abortions should be expected approximately in 30% of cases, several other causes should be considered as the source of pregnancy interruption. In order of importance Neospora caninum is the major abortive pathogen in Northeastern Italy, bacterial or fungal agents are the second, with prevalence ranging from 12-14%, while BVD virus and Coxiella. burnetii are less likely to be isolated.

Retrospective study on the surveillance on dairy cows infective abortions in Northeastern Italy from 2006 to 2019 / Coin, Patrizio; Dall'Ava, Brunella; Martignago, Federico; Tonellato, Francesca; Schiavon, Eliana; Capello, Katia; Vesentini, Giacomo; Cornaggia, Matteo; Cavirani, Sandro; Barberio, Antonio. - (2022), pp. 116-117. ((Intervento presentato al convegno 31st World Buiatrics Congress tenutosi a Madrid, Spain nel September 4th to 8th, 2022.

Retrospective study on the surveillance on dairy cows infective abortions in Northeastern Italy from 2006 to 2019

Sandro Cavirani;
2022

Abstract

Objectives: Bovine abortion is an important cause of economic loss in dairy cattle, and has important implications in public veterinary health. Veneto region, in Northeastern Italy, has implemented since year 2006 an official surveillance plan on abortion in dairy cattle. The aim of this study is to describe the results of this surveillance, from 2006 to 2019, and to provide information about the occurrence of abortive pathogens and their prevalence. Material and methods: Aborted fetuses, accompanied by the dam’s blood sample, were delivered to the Regional State Veterinary Laboratory (IZSVe), and submitted to a panel of laboratory tests. The cows’ sera were tested for antibodies against Neospora caninum, Chlamydophila abortus, Coxiella burnetii, IBR virus, and BVD non structural protein NS2-3 by mean of commercial ELISA tests, and to Brucella abortus and melitensis following the EU regulation mandatory method. Antibody against Coxiella burnetii were detected using also the complement fixation test according to OIE guideline. On all the fetuses were performed necroscopy, microbiological culture from abomasum, histopathology from lung, and detection, by PCR from spleen, of BVD virus, Chlamydia spp., and Coxiella. burnetii. Detection of Neospora caninum by PCR from the brain was performed only on fetuses older than four month. Brucella spp isolation was carried out only if the abortion occurred after the fifth pregnancy month; while Campylobacter fetus isolation was performed on abortions occurred before the fifth month. A PCR for the detection of Schmallenberg virus from the brain was introduced after year 2013. Results: During these years (2006-2019) 4,562 bovine abortions were delivered to IZSVe, 668 of them were under the fifth month of gestation (14.6%). The most of fetuses delivered were autolytic (62.7%), without macroscopic lesions (30.8%) or mummified (4.5%). Histologically lung inflammatory lesions were present in 32.8% of cases. An infective agent was detected in 1451 fetuses (31.8%). Neospora caninum was the most frequent specific abortion agent isolated (22.2%), followed by BVD virus (5.7%), Coxiella. Burnetii (4.7%) and Chlamydia spp (0.7%). Schmallenberg virus was detected only in 3 fetuses delivered respectively in year 2012, 2013 and 2014, but only one showed congenital abnormalities (limbs arthrogryposis and jaw malformation). Microbiological culture was considered positive only when specific abortifacient pathogens were isolated: according to this criteria the 13% had a culture positive test. Among the bacteriological agents isolated the most relevant were T. pyogenes (47.4%), Bacillus spp. (29.4%), Streptococcus spp. (15.8%), L. monocytogenes and fungi (1.9%), P. multocida (1.7%), Salmonella spp. (1.1%), M. haemolytica (0.7%), Corynebacterium spp. (0.2%). Campylobacter fetus was isolated in one abortion and Brucella spp. was never isolated. Serological tests showed a high percentage of cows had antibodies against BVD virus (44.8%), Chlamydophila abortus (41.3%), Neospora caninum (33.2%); IBR virus (25.4%), C. burnetii (15.8%). All tested sera and abortions were negative for Brucella spp. The agreement between serological test and PCR for Neospora caninum was substantial (Cohen’s kappa (k) = 0.667, while the agreement for BVD virus and C. burnetii was slight (k = 0.11; k = 0.16). Conclusions: In our opinion, the abortion surveillance program provided many useful and interesting information about the health status of dairy farms and the diagnostic methods suitable for abortion diagnosis. Necroscopy findings showed the low prevalence of specific macroscopic lesion in fetuses, highlighting the importance to use a standardized protocol including tests for detection of the most relevant abortion agents. Infective abortions should be expected approximately in 30% of cases, several other causes should be considered as the source of pregnancy interruption. In order of importance Neospora caninum is the major abortive pathogen in Northeastern Italy, bacterial or fungal agents are the second, with prevalence ranging from 12-14%, while BVD virus and Coxiella. burnetii are less likely to be isolated.
Retrospective study on the surveillance on dairy cows infective abortions in Northeastern Italy from 2006 to 2019 / Coin, Patrizio; Dall'Ava, Brunella; Martignago, Federico; Tonellato, Francesca; Schiavon, Eliana; Capello, Katia; Vesentini, Giacomo; Cornaggia, Matteo; Cavirani, Sandro; Barberio, Antonio. - (2022), pp. 116-117. ((Intervento presentato al convegno 31st World Buiatrics Congress tenutosi a Madrid, Spain nel September 4th to 8th, 2022.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2929877
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