Prevalence of chlamydiae in dairy cattle herds and factors contributing to the spread of infections

Abstract

Introduction: Different Chlamydia species affect cattle and contribute to economic losses. One of them, C. pecorum, is a globally endemic livestock pathogen. Despite its endemicity, prevalence data from Poland have so far been limited. The present study aimed to obtain insight into the chlamydiae prevalence in Polish dairy cattle.

Material and methods: A screening of chlamydial seroprevalence in dairy cattle was initially performed, followed by Chlamydiaceae- and species-specific real-time qPCR. Vaginal swabs (n = 239) and placenta samples (n = 2) from seropositive animals in 142 herds were collected to detect shedders. The study population consisted of cows (n = 2,780) from dairy herds (n = 1,153) located in all Polish voivodeships.

Results: The true animal prevalence was determined to be 33.3%, while the true herd prevalence was 42.7%. Five groups of Polish voivodeships were identified using appropriate statistical tools, highlighting differences that may arise from various factors impacting the spread of chlamydial infections. The only detected chlamydia species was C. pecorum, the presence of which was confirmed in two herds.

Conclusion: This study revealed that chlamydial infections are commonly present in Polish dairy cattle across the country.

Keywords: chlamydiae; dairy cattle; prevalence.

Fig 1.

True seroprevalence of chlamydiae at animal and herd level in cattle herds in the voivodeships of Poland based on serum analyses by complement fixation test. TPH – true-positive herds; TPA – true-positive animals; Voivodeships: GP – Greater Poland; PDL – Podlaskie; SW – Świętokrzyskie, LDZ – Łódź; KP – Kuyavia-Pomerania; MAS – Masovia; OPO – Opole; LP – Lesser Poland; SUB – Subcarpathia; WP – West Pomerania; LB – Lublin; SL – Silesia; POM – Pomerania; LS – Lower Silesia; LU – Lubusz; WM – Warmia-Masuria – the size of the symbol corresponds to the number of cows in the voivodeship

Fig. 2.

Multivariate analysis of the presence of antibodies against chlamydiae in sera at herd and animal level, the geographical location of the farms and the dairy cow stock in the voivodeship and the positive and negative conformity rates between the results of serological screening for chlamydiae and Coxiella burnetii in the same sera samples. Blue points represent each category of analysed variables. Blue points with similar profiles (low value of distances indicating a strong association between variables) are marked by the red rectangles. Blue points located in the green rectangle in the graph’s centre show the points with similar profiles but representing eigenvalues indicating the lack of any association. Blue points located in the dashed rectangle shows the points with similar profiles but representing eigenvalues indicating the association with more than one groups ACh+ – seroprevalence of chlamydiae at animal level; HCh+ – seroprevalence of chlamydiae at herd level; CP – dairy cattle population; Con Pos Q/Ch – conformity between positive results of presence of Chlamydia spp. and Coxiella burnetii antibodies in the same sera samples; Con Neg Q/Ch – conformity between negative results of presence of Chlamydia spp. and Coxiella burnetii antibodies in the same sera samples. Voivodeships: GP – Greater Poland; PDL – Podlaskie; SW – Świętokrzyskie, LDZ – Łódź; KP – Kuyavia-Pomerania; MAS – Masovia; OPO – Opole; LP – Lesser Poland; SUB – Subcarpathia; WP – West Pomerania; LB – Lublin; SL – Silesia; POM – Pomerania; LS – Lower Silesia; LU – Lubusz; WM – Warmia-Masuria