Infectious abortions in small domestic ruminants in the Iberian Peninsula: Optimization of sampling procedures for molecular diagnostics

Abstract

IntroductionInfectious abortions have a major impact on small domestic ruminant farms, i.e., sheep and goats, both in terms of profitability and health status. Therefore, rapid and sensitive diagnosis is essential to minimize losses. Currently, molecular techniques, such as qPCR, are routinely used for their diagnosis, which imply the need to manipulate all abortive material, with consequent biosafety risks. Here, we evaluate the frequency of the main abortifacient pathogens in small domestic ruminants in the Iberian Peninsula and also assess an alternative approach for the optimization of sampling for molecular diagnosis.ResultsA total of 392 clinical cases were analyzed from April 2020 to May 2021, evidencing that the main causative agents of abortion detected were Coxiella burnetii (49.0%), Chlamydia abortus (38.3%) and, to a lesser extent, Toxoplasma gondii (10.2%), Salmonella enterica (7.1%) and Campylobacter spp. (6.1%). An uneven distribution of these pathogens was observed between ruminant species, with a higher frequency (p < 0.05) of T. gondii, S. enterica and Campylobacter spp. in sheep than goat abortions, and among geographic areas, highlighting the higher frequency (p < 0.05) of T. gondii and Campylobacter spp. in the north compared to southeastern Spain. The alternative sampling method, consisting on the use of fetal tongues and placental swabs in replacement of the whole fetus and placental tissue, offered a very good agreement with the classical method for all pathogens, except for low concentrations of C. burnetii, which seems to have a doubtful role in abortion when its concentration in the abortifacient material is low.ConclusionsThis study reveals a high frequency of infectious etiology in abortions of small domestic ruminants in the Iberian Peninsula and validates for the first time an alternative sampling method for molecular diagnosis that will help to provide rapid and accurate results while minimizing biosafety risks.

Biomolecular survey on the main infectious causes of abortion in sheep in the Italian regions of Latium and Tuscany

“…Our results showed 12 different types of co-infection; in 8 of these, C. abortus is often present, and there seems to be a correlation between the presence of C. abortus and the presence of several pathogens at the same time ( Alzuguren et al ., 2023 ).…”

Sero-epidemiological study of zoonotic bacterial abortifacient agents in small ruminants

“…Abortifacient agents are the essential factors for tremendous losses in the livestock industry. These losses are caused by infertility, stillbirths, repeated breeding, decreased milk production, meat loss by aborted fetuses, additional treatment management costs, and veterinary services ( 1 , 2 ). Moreover, abortion is a significant threat to public health when caused by zoonotic organisms.…”

Seroprevalence and Risk Factors Associated with Chlamydia abortus Infection in Sheep and Goats in North-Western Italy

“…This resistance, as for C. burnetii, seems to increase the possibility of coming into contact with many animal species, farmed or wild, and with humans [1,3]. Referring to the literature data on PCR-based methods, co-infections in clinical cases of abortion are relatively frequent in small ruminants [8][9][10]. Taking the results published in an authors' previous study on the seroprevalence of Q fever [11] structured on a well-defined study design to accurately estimate the prevalence of the infection [12] as a starting point and considering the direct evidence of co-infections based on biomolecular methods [8][9][10], in this study, we propose a retrospective seroprevalence study on sheep and goat serum samples.…”