A case–control study to estimate the effects of acute clinical infection with the Schmallenberg virus on milk yield, fertility and veterinary costs in Swiss dairy herds

Wüthrich, M.; Lechner, Isabel; Aebi, Marlis; Vögtlin, Andrea; Posthaus, Horst; Schüpbach‐Regula, Gertraud; Meylan, Mireille

doi:10.1016/j.prevetmed.2016.01.021

Cited by 13 publications

(8 citation statements)

References 23 publications

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“…After its first detection in 2011, SBV spread rapidly across Europe, including Switzerland ( Hoffmann et al., 2012 ), where it was detected in bulk tank milk samples and in serum from healthy cows ( Balmer et al., 2014 , 2015 ). In a previous study at the national level, no significant differences in fertility were observed between case (SBV-positive) farms and control farms ( Wüthrich et al., 2016 ). This is the first study to include results from SBV testing in a broad-spectrum analysis of bovine abortions in Switzerland.…”

Section: Discussionmentioning

confidence: 68%

Limited added value of fungal ITS amplicon sequencing in the study of bovine abortion

Vidal

Brandt

Dettwiler

et al. 2018

Heliyon

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Bovine mycotic abortion is sporadic and caused by different ubiquitous and opportunistic fungi. Recently, a broad spectrum of bacterial opportunists involved in bovine abortion was revealed by 16S rRNA gene amplicon sequencing. We hypothesized that fungal organisms potentially involved in bovine abortion also might remain undetected by conventional culture. In this retrospective study, we therefore applied fungal internal transcribed spacer 2 (ITS2) region amplicon sequencing to 74 cases of bovine abortion submitted to our diagnostic service. The investigation was complemented by fungal culture and, retrospectively, by data from bacteriological, virological and parasitological analyses and histopathological examination of placentas.Fungal DNA was found in both the placentas and abomasal contents, with 92 fungal genera identified. In 18 cases, >75% of the reads belonged to one specific fungal genus: Candida (n = 7), Malassezia (n = 4), Cryptococcus (n = 3), unidentified Capnodiales (n = 3), Actinomucor (n = 1), Cystofilobasidium (n = 1), Penicillium (n = 1), Verticillum (n = 1) and Zymoseptoria (n = 1) with one case harboring two different genera. By culture, in contrast, fungal agents were detected in only 6 cases. Inflammatory and/or necrotizing lesions were found in 27/40 histologically assessed placentas. However, no lesion-associated fungal structures were detected in HE- and PAS-stained specimens. Complementary data revealed the presence of one or more non-fungal possible abortifacient: Chlamydiales, Coxiella burnetii, Leptospira spp., Campylobacter fetus subsp. fetus, Streptococcus uberis, Escherichia coli, Streptococcus pluranimalium, Bacillus licheniformis, Campylobacter fetus subsp. fetus, Serratia marcescens, Trueperella pyogenes, Schmallenbergvirus, Neospora caninum. The mycobiota revealed by sequencing did not differ between cases with or without a possible infectious etiology.Our study suggests that amplicon sequencing of the ITS2 region from DNA isolated from bovine abortion does not provide additional information or new insight into mycotic abortion and without complementary analyses may easily lead to a false interpretation of the role of fungal organisms in bovine abortion.

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Section: Discussionmentioning

confidence: 68%

Limited added value of fungal ITS amplicon sequencing in the study of bovine abortion

Vidal

Brandt

Dettwiler

et al. 2018

Heliyon

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“…Depending on the time of exposure, this may result in abortion or severe congenital malformations causing dystocia and the birth of non-viable calves [114,115]. A case control study on Swiss dairy farms found that the abortion rate increased to 6.5% in 2012 when the SBV infection started, in comparison with a rate of 3.7% the year before [116].…”

Section: Schmallenberg Virusmentioning

confidence: 99%

Importance of Viral Disease in Dairy Cow Fertility

et al. 2020

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a b s t r a c tMany viral diseases are endemic in cattle populations worldwide. The ability of many viruses to cross the placenta and cause abortions and fetal malformations is well understood. There is also significant evidence that viral infections have additional actions in dairy cows, which are reflected in reduced conception rates. These effects are, however, highly dependent on the time at which an individual animal first contracts the disease and are less easy to quantify. This paper reviews the evidence relating to five viruses that can affect fertility, together with their potential mechanisms of action. Acute infection with non-cytopathic bovine viral diarrhea virus (BVDV) in mid-gestation increases abortion rates or causes the birth of persistently infected calves. BVDV infections closer to the time of breeding can have direct effects on the ovaries and uterine endometrium, which cause estrous cycle irregularities and early embryo mortality. Fertility may also be reduced by BVDV-induced immunosuppression, which increases the susceptibility to bacterial infections. Bovine herpesvirus (BHV)-1 is most common in pre-pubertal heifers, and can slow their growth, delay breeding, and increase the age at first calving. Previously infected animals subsequently show reduced fertility. Although this may be associated with lung damage, ovarian lesions have also been reported. Both BHV-1 and BHV-4 remain latent in the host following initial infection and may be reactivated later by stress, for example associated with calving and early lactation. While BHV-4 infection alone may not reduce fertility, it appears to act as a co-factor with established bacterial pathogens such as Escherichia coli and Trueperella pyogenes to promote the development of endometritis and delay uterine repair mechanisms after calving. Both Schmallenberg virus (SBV) and bluetongue virus (BTV) are transmitted by insect vectors and lead to increased abortion rates and congenital malformations. BTV-8 also impairs the development of hatched blastocysts; furthermore, infection around the time of breeding with either virus appears to reduce conception rates. Although the reductions in conception rates are often difficult to quantify, they are nevertheless sufficient to cause economic losses, which help to justify the benefits of vaccination and eradication schemes.

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“…It was shown that SBV infection in meat sheep herds caused increased rates of abortion, malformations, dystocia, lamb mortality and reduced fertility rate [16]. A study conducted by Wüthrich et al [17] revealed that the average calculated loss after SBV infection for a standardized farm was EUR 1338, which can be considered low at the national level, but the losses were subject to great fluctuations between farms, so individual farms could have very high losses (EUR 8333). The overall prevalence of infected animals within a herd is an important factor [17], and the economic impact of the infection depends on several aspects, such as, the number of malformed lambs, days where milk production is lower and stage of pregnancy on which the infection occurred [9,17].…”

Section: Schmallenberg Virus Impact On Ruminant Healthmentioning

confidence: 99%

“…A study conducted by Wüthrich et al [17] revealed that the average calculated loss after SBV infection for a standardized farm was EUR 1338, which can be considered low at the national level, but the losses were subject to great fluctuations between farms, so individual farms could have very high losses (EUR 8333). The overall prevalence of infected animals within a herd is an important factor [17], and the economic impact of the infection depends on several aspects, such as, the number of malformed lambs, days where milk production is lower and stage of pregnancy on which the infection occurred [9,17]. However, the emergence of SVB has a financial impact on international trade in live sheep and goats, for example, with some countries (USA, Mexico and Japan), to place restrictions on the import of embryos and semen of Europe [9].…”

Section: Schmallenberg Virus Impact On Ruminant Healthmentioning

confidence: 99%

Epidemiology and Emergence of Schmallenberg Virus Part 1: Origin, Transmission and Differential Diagnosis

Esteves¹,

Mesquita²,

Nóbrega³

et al. 2016

Epidemiology of Communicable and Non-Communicable Diseases - Attributes of Lifestyle and Nature on Humankind

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Schmallenberg virus (SBV) is a novel Orthobunyavirus causing mild clinical signs in cows and malformations in aborted and neonatal ruminants in Europe. SBV belongs to the family Bunyaviridae and is transmitted by biting midges. This new virus was identified for the first time in the blood samples of cows in the city of Schmallenberg in NorthRhine-Westphalia in November 2011. Since then the virus spread to several European countries. Here we describe the origin and emergence, as well as the transmission and the differential diagnosis of this virus, now known to be a serious threat to Veterinary Public Health.

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A case–control study to estimate the effects of acute clinical infection with the Schmallenberg virus on milk yield, fertility and veterinary costs in Swiss dairy herds

Cited by 13 publications

References 23 publications

Limited added value of fungal ITS amplicon sequencing in the study of bovine abortion

Limited added value of fungal ITS amplicon sequencing in the study of bovine abortion

Importance of Viral Disease in Dairy Cow Fertility

Epidemiology and Emergence of Schmallenberg Virus Part 1: Origin, Transmission and Differential Diagnosis

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