Switzerland-wide Neospora caninum seroprevalence in female cattle and identification of risk factors for infection

Abstract

IntroductionNeospora caninum is an important cause of abortion in cattle worldwide. Infection in cattle occurs horizontally by ingestion of oocysts shed by canids or vertically, from an infected dam to the fetus, and may result in abortion, stillbirth, or birth of seropositive offspring. The control of bovine neosporosis is difficult and costly. The objectives of this study were to estimate the current nationwide seroprevalence of N. caninum infections in Swiss cattle and to assess risk factors for infection with this parasite.MethodsWe conducted a cross-sectional study with cattle farms randomly selected and stratified according to population size, resulting in a sample of 780 female cattle. The cattle originated from 161 farms distributed over all Switzerland. The serum samples were tested for antibodies against N. caninum using a commercial ELISA and if inconclusive, retested using an in-house immunoblot technique. To collect farm parameters relevant to N. caninum transmission and prevention, farm owners were mailed a questionnaire which addressed topics putatively related to N. caninum infection such as husbandry, history of abortion, and presence of dogs on farm. Univariate analysis by generalized linear mixed model (with animal seropositivity as outcome variable) and logistic regression modeling (with farm seropositivity as outcome variable) was conducted on farm parameters investigated in the questionnaire.ResultsBy ELISA and immunoblot, 4.2% (33/780) of cattle sera yielded positive results. At the farm level, 16.2% (26/161) of the sampled farms had at least one seropositive animal. The return rate of the valid questionnaires was 54.0%. At the animal level, odds for farm seropositivity were 3.8 times higher when rodents had been recorded by the farmer as a problem on the farm. At the farm-level, two protective factors were identified: rearing of replacement heifers and feeding of concentrated feed.ConclusionWe recorded a low seroprevalence of N. caninum in a random sample of Swiss cattle representative for the years 2017–2018. Based on a questionnaire survey, we could identify risk and protective factors for infection with N. caninum, however their biological relevance needs to be confirmed in further studies.

SEROLOGICAL SCREENING FOR Neospora caninum INFECTION IN A DAIRY CATTLE FARM WITH REPRODUCTIVE DISORDERS, IN SOUTH-EASTERN ROMANIA

“…caninum can be maintained in cattle herds through generations (Almeria et al, 2017;Ikonnikova et al, 2023). Carrier cattle can suffer reproductive disorders at any time due to the reactivation of the infection; therefore, the identification of positive dams is necessary to prevent the spread of disease (Gliga et al, 2022). Serological studies conducted on neosporosis in cattle have been published in many parts of the world and reported differences in prevalence between countries and within countries, between regions, and between dairy and beef cattle (Dubey & Schares, 2011;Kowalczyk et al, 2016).…”

“…Serological studies conducted on neosporosis in cattle have been published in many parts of the world and reported differences in prevalence between countries and within countries, between regions, and between dairy and beef cattle (Dubey & Schares, 2011;Kowalczyk et al, 2016). In European countries, N. caninum seroprevalence rates in dairy cattle varied between 16% and 76% (Gliga et al, 2022), and the association between reproductive disorders and neosporosis has already been reported. In Romania, the prevalence of infection with N. caninum reported in several serological studies in cattle, carried out in different areas of the country, varies from 5.1% to 60.3% (Gavrea & Cozma, 2010;Gavrea et al, 2011;Imre et al, 2011;Mitrea et al, 2012;Enachescu et al, 2012a;Gotu et al, 2021) and dogs (Enachescu et al, 2012b;Mitrea et al, 2013).…”