Coxiella burnetii associated reproductive disorders in domestic animals-a critical review

Abstract

The bacterium Coxiella burnetii has been detected in the fetal membranes, birth fluids and vaginal mucus, as well as in the milk and other excretions of several domestic mammals. The finding of C. burnetii in association with abortion, parturition and in the postpartum period has led to the hypothesis that C. burnetii causes a range of reproductive diseases. This review critically evaluates the scientific basis for this hypothesis in domestic mammals.The review demonstrates a solid evidence for the association between C. burnetii infection and sporadic cases of abortion, premature delivery, stillbirth and weak offspring in cattle, sheep and goats. C. burnetii induced in-herd epidemics of this complete expression of reproductive failure have been reported for sheep and goats, but not for cattle. The single entities occur only as part of the complex and not as single events such as generally increased stillbirth rate. Studies show that C. burnetii initially infects the placenta and that subsequent spread to the fetus may occur either haematogenous or by the amniotic-oral route. The consequences for the equine, porcine, canine and feline conceptus remains to the elucidated but that infection of the conceptus may occur is documented for most species. There is no solid evidence to support a hypothesis of C. burnetii causing disorders such as subfertility, endometritis/metritis, or retained fetal membranes in any kind of domestic animal species.There is a strong need to validate non-pathology based methods such as polymerase chain reaction for their use in diagnostic and research in relation to establishing C. burnetii as the cause of abortion and to adapt an appropriate study design and include adequate control animals when linking epidemiological findings to C. burnetii or when evaluating effects of vaccination in production herds.

Early neonatal lamb mortality: postmortem findings

“…The proportion of affected lambs (10%) was similar to the findings in previous studies of causes of neonatal lamb mortality (Wiener et al, 1983;Green and Morgan, 1993). Other infectious agents that are recognized as sources of reproductive losses in sheep in Europe, but not specifically screened for in this study are Chlamydophila abortus, Coxiella burnetii and pestivirus causing border disease (Nettleton et al, 1998;Aitken and Longbottom, 2007;Agerholm, 2013). Enzootic ovine abortion caused by C. abortus has never been diagnosed in Norway (Kampen A., Norwegian Veterinary Institute, personal communication) and there is no indication that C. burnetii infections are present in farmed ruminants in Norway (Kampen et al, 2012).…”

Occurrence of Coxiella burnetii and Chlamydiales species in abortions of domestic ruminants and in wild ruminants in Hungary, Central Europe

“…The abortive characteristics of C. burnetii have not been confirmed experimentally in cattle, and the pathogen is suggested to be an infrequent cause of abortions in this animal species even in endemic areas. 1 In the present study, the regularly high Ct values (22.3%, 19/85), and the absence of antigen detection suggest subclinical infections in the hosts and that C. burnetii should not be considered as a significant abortive agent in cattle in the country.…”

Coxiella burnetii total immunoglobulin G, phase I and phase II immunoglobulin G antibodies, and bacterial shedding in young dams in persistently infected dairy herds

“…5,14 Infected cattle shed high numbers of C. burnetii in milk, vaginal mucus, feces, 14 urine, 6 and, importantly, birth products, 17 and generally exhibit subclinical symptoms. 1 However, reproductive disorders such as placental damage, abortion, stillbirth, placental retention, or infertility have been linked to C. burnetii infection in dairy herds. 12,15,23 To control C. burnetii infection at the herd level, treatment with antibiotics (tetracycline) or vaccination may reduce, but not prevent, bacterial shedding.…”