Prevalence of Coxiella burnetii antibodies in bulk milk and blood serum and associations with reproductive indices in cow dairy herds of Central and Northern Greece

Abstract

For the first time in Greece, we investigated the prevalence of Coxiella burnetii antibodies in milk and sera from dairy cattle herds located at central and northern parts of the country. Eighty herds were initially voluntary enrolled in the study and a bulk milk sample from each farm was assayed by ELISA for C burnetii antibodies. According to antibody titre, herds were classified into 5 categories: negative and grades 1,2,3 and 4 (ascending scale). To assess the prevalence within farms, two herds from each category were selected and blood samples were collected for antibody assessment. In these herds, some reproductive indices were compared between farms; in addition, comparisons were made in paired seropositive and seronegative animals from one grade 3 herd. Twenty three herds (35%) were found positive, 21 being in categories 3 and 4. The prevalence of seropositive animals between herds varied from 4.9 to 46.3%, even from farms initially characterized as negative, some positive animals were detected. Between farms, no differences were detected in the abortion rate or in the mean number of artificial inseminations (AI) per pregnancy. Some differences were found in other reproductive indices that were impossible to be biologically interpreted under the light of C. burnetii level of infection. From the results presented here, we infer that C. burnetii infection is likely asymptomatic in dairy cows causing minimal -if any- economic losses to farmers. However, since the disease is a zoonotic one, its spread can easily occur, a systematic surveillance, in all ruminant species, for the restriction or eradication of the disease should be undertaken in national level.

Coxiella burnetii Shedding in Milk and Molecular Typing of Strains Infecting Dairy Cows in Greece

“…Despite the aforementioned importance of C. burnetii, there is a lack of studies concerning infection with this pathogen in animals in Greece. There are a couple of serological studies in sheep and goats [19,20] and one serological study in dairy cows [21]. Molecular characterization of strains was approached in a single recent work, which examined aborted sheep fetuses [22].…”

Coxiella burnetii and Reproductive Disorders in Cattle: A Systematic Review

“…The authors concluded that, in this case, C. burnetii was not a major aetiology of puerperal metritis. A study in Greece [46] also found no association between the presence of C. burnetii antibodies and uterine infection. Turcotte and colleagues [81] conducted a study about 5 weeks after calving to estimate the prevalence of C. burnetii in dairy cows from PCR-positive and/or seropositive herds.…”

“…Similarly, in a small study involving 43 dairy cows, Garcia-Ispierto and colleagues [80] found that seropositive cows were no more likely to have an RFM than seronegative cows. Furthermore, a large study in Greece [46] grouped herds according to BTM antibody titre to C. burnetii. One-third of herds were deemed positive, and two herds per each of five herd groups (including a control group) were selected for further serum antibody titre assessments.…”

“…In contrast, a follow-up study by the same group [43] demonstrated that neither C. burnetii infections (antigen) nor seropositivity were significantly associated with the number of inseminations, despite both C. burnetii antigen and antibody levels being significantly associated with an increased incidence of abortion. Dovolou and colleagues [46] looked at 80 dairy herds for the seroprevalence of C. burnetii. BTM samples were assayed by ELISA, and 35% of herds were considered positive-these were then graded as 1, 2, 3 and 4 based on antibody titre (ascending order).…”