Neglected zoonotic agents in cattle abortion: tackling the difficult to grow bacteria

Abstract

Background Coxiella burnetii, Chlamydia abortus and Leptospira spp. are difficult to grow bacteria that play a role in bovine abortion, but their diagnosis is hampered by their obligate intracellular lifestyle (C. burnetii, C. abortus) or their lability (Leptospira spp.). Their importance is based on the contagious spread in food-producing animals, but also as zoonotic agents. In Switzerland, first-line routine bacteriological diagnostics in cattle abortions is regulated by national law and includes only basic screening by staining for C. burnetii due to the high costs associated with extended spectrum analysis. The aim of this study was to assess the true occurrence of these zoonotic pathogens in 249 cases of bovine abortion in Switzerland by serology (ELISA for anti-C. burnetii and C. abortus antibodies and microscopic agglutination test for anti-Leptospira spp. antibodies), molecular methods (real-time PCR and sequencing of PCR products of Chlamydiales-positive cases), Stamp’s modification of the Ziehl-Neelsen (mod-ZN) stain and, upon availability of material, by histology and immunohistochemistry (IHC).ResultsAfter seroanalysis the prevalence was 15.9% for C. burnetii, 38.5% for C. abortus and 21.4% for Leptospira spp. By real-time PCR 12.1% and 16.9% of the cases were positive for C. burnetii and Chlamydiales, respectively, but only 2.4% were positive for C. burnetii or Chlamydiales by mod-ZN stain. Sequencing of PCR products of Chlamydiales-positive cases revealed C. abortus in 10% of cases and the presence of a mix of Chlamydiales-related bacteria in 5.2% of cases. Pathogenic Leptospira spp. were detected in 5.6% of cases. Inflammatory lesions were present histologically in all available samples which were real-time PCR-positive for Chlamydiales and Leptospira spp. One of 12 real-time PCR-positive cases for C. burnetii was devoid of histological lesions. None of the pathogens could be detected by IHC.ConclusionMolecular detection by real-time PCR complemented by histopathological analysis is recommended to improve definitive diagnosis of bovine abortion cases and determine a more accurate prevalence of these zoonotic pathogens.Electronic supplementary materialThe online version of this article (10.1186/s12917-017-1294-y) contains supplementary material, which is available to authorized users.

Bovine Fetal Placenta During Pregnancy and the Postpartum Period

“…In total, 14 of 43 positive samples for Chlamydiales real-time PCR showed placentitis and necrosis, 12 of 14 samples mixed inflammation, and 7 of 14 samples vasculitis. 41 By PCR, all 91 investigated cases were negative for N. caninum. Another study examined the relevance of N. caninum as a bovine abortifacient pathogen in Swiss farms with abortion problems (n ¼ 113) compared with control farms (n ¼ 113).…”

“…Of these, 35 positive samples of placentitis were present in 12 of 13 cases, necrosis was present 11 of 13 cases, mixed inflammatory infiltrates were found in 9 of 13 cases, and vasculitis was present in 5o f1 3c a s e s . 41 The diagnostic investigation of abortion is a stepwise process, which includes collection of appropriate samples, recording of a complete case history, macroscopic examination, microbiologic investigations,a sw e l la sh i s t o p a t h o l o g ya n d molecular analyses. Linking molecular results to macroscopic and/or microscopic findings is crucial to confirm the cause of abortion and to prevent false-positive results.…”

Coxiella burnetii associated with BVDV (Bovine Viral Diarrhea Virus), BoHV (Bovine Herpesvirus), Leptospira spp., Neospora caninum, Toxoplasma gondii and Trypanosoma vivax in reproductive disorders in cattle

“…Although serological evidence of exposure to C. burnetii has already been reported in cattle in Europe (CZAPLICKI et al, 2009;AGGER et al, 2010;BOTTCHER et al, 2011;GACHE et al, 2017;RYAN et al, 2018;VARELA-CASTRO et al, 2018;VIDAL et al, 2017;SOFTIC et al, 2018), Asia (CETINKAYA et al, 2000NOKHODIAN et al, 2016), North America (MCQUISTON et al, 2005 and Africa (KAMGA-WALADJO et al, 2010;SCOLAMACCHIA et al, 2010), there are few data on seroprevalence to this agent in ruminants in Brazil. In this regard, while Guimarães et al (2017) found a seropositivity rate of 2% for C. burnetii among sheep sampled in the state of Piauí, northeast of Brazil, Oliveira et al (2018) found a seroprevalence of 55.1% in a herd of goats with history of reproductive disorders in the state of Alagoas, Northeast of Brazil.…”

Infektiös bedingte Aborte beim Rind – eigene Erfahrungen und Untersuchungen aus dem Jahr 2018 (Januar–September)

“…Untersuchungen zu Abortursachen bei Rindern aus der Schweiz [19] ergaben mit 15,9 % maternalen Blutproben mit Nachweis von Coxiella burnetii-Ak eine etwas geringere Seroprävalenz als in der vorliegenden Arbeit mit 21 %. Es konnten jedoch bei 38,5 % der Schweizer Tiere Ak gegen Chlamydia abortus nachgewiesen werden, während in der vorliegenden Studie alle maternalen Blutproben für Chlamydia abortus-Ak negativ waren.…”

“…Bei der Interpretation einzelner Ak-Nachweise in maternalen Blutproben von Einzeltieren ist darauf zu achten, dass diese einen Hinweis auf eine Exposition mit einem spezifischen Pathogen oder einem Impfantigen geben, jedoch keine Auskunft über den Zeitpunkt [5] [19]. So konnte bei gesunden Kühen eine vergleichbare Coxiella burnetii-Seroprävalenz nachgewiesen werden wie bei Tieren mit Abortproblematik [19].…”