High frequency of chlamydial co-infections in clinically healthy sheep flocks

Abstract

BackgroundThe epidemiological situation of ovine chlamydial infections in continental Europe, especially Germany is poorly characterised. Using the German state of Thuringia as a model example, the chlamydial sero- and antigen prevalence was estimated in thirty-two randomly selected sheep flocks with an average abortion rate lower than 1%. Seven vaccinated flocks were reviewed separately.ResultsA wide range of samples from 32 flocks were examined. Assumption of a seroprevalence of 10% (CI 95%) at flock level, revealed that 94% of the tested flocks were serologically positive with ongoing infection (i.e. animals with seroconversion) in nearly half (47%) of the flocks. On the basis of an estimated 25% antigen prevalence (CI 95%), PCR and DNA microarray testing, together with sequencing revealed the presence of chlamydiae in 78% of the flocks. The species most frequently found was Chlamydophila (C.) abortus (50%) followed by C. pecorum (47%) and C. psittaci genotype A (25%). Mixed infections occurred in 25% of the tested flocks. Samples obtained from the vaccinated flocks revealed the presence of C. abortus field samples in 4/7 flocks. C. pecorum was isolated from 2/7 flocks and the presence of seroconversion was determined in 3/7 flocks.ConclusionsThe results imply that chlamydial infections occur frequently in German sheep flocks, even in the absence of elevated abortion rates. The fact that C. pecorum and the potentially zoonotic C. psittaci were found alongside the classical abortifacient agent C. abortus, raise questions about the significance of this reservoir for animal and human health and underline the necessity for regular monitoring. Further studies are needed to identify the possible role of C. psittaci infections in sheep.

Analysis of Humoral Immune Responses to Surface and Virulence-Associated Chlamydiaabortus Proteins in Ovine and Human Abortions by Use of a Newly Developed Line Immunoassay

“…The human and animal serum samples used in this study were taken from already existing serum collections of previous studies (4,5,7,10,13,14). Human serum samples were anonymized, and their use was approved by the local ethics committee of the University of Ulm (96/09) and the local ethics committee of the University Hospital Jena (2525-04/09).…”

“…abortus typically occurs in ruminants such as sheep and goats and is the leading cause of enzootic abortion of ewes (EAE) worldwide (3). Even in the absence of elevated abortion rates, the agent was shown to be widespread in German sheep flocks, with 50% of flocks testing PCR positive and 94% harboring seropositive animals (4). Afterbirths and fetuses of abortion cases can contain heavy loads of the pathogen and represent the major source of transmission to susceptible humans and naive ewes, as well as environmental contamination (3).…”

Detection of Circulating Immunoglobulins in Serum of Sheep Naturally Infected with Chlamydia Trachomatis and Listeria Monocytogenes in Two Egyptian Provinces

“…Lenzko et al (2011) reported that 94% of the tested sheep flocks were serologically positive with chalamydial infection in Germany. Moreover, Husu, (1990) and stated that L. monocytogenes was a ubiquitous organism, and regular exposure of animals and humans to this microorganism was very common.…”

“…The fact that there are scarcity of data regarding the relations between C. trachomatis, L. monocytogenes and infertility cases in Egypt. Therefore, this study was aimed in the main to elucidate the seroprevalence of C. trachomatis and L. monocytogenes infection among sheep, Moreover, C. trachomatis and L. monocytogenes are potentially zoonotic agents raise questions about the significance of this reservoir for animal and human health and underline the necessity for regular monitoring (Lenzko et al 2011 Sensitivity: 0.1nnmol/L (the sensitivity of this assay was defined as the lowest protein concentration that could be differentiated from zero. It is determined by sub-tracing two standards' deviations to the mean optical density value of twenty zero standard replicates and calculating the corresponding concentration.…”

Chlamydial Abortion in Algerian Small Ruminants

“…Chlamydial infection is one of the pathologies which induce abortion in small ruminants; two species of Chlamydia have been reported to cause infections in sheep, C. abortus and C. pecorum (Lenzko et al, 2011). These bacteria have a unique developmental cycle.…”