Q fever and toxoplasmosis in South African livestock and wildlife: a retrospective study on seropositivity, sporadic abortion, and stillbirth cases in livestock caused by Coxiella burnetii

Abstract

Background: Q fever and toxoplasmosis are economically important zoonoses as they cause considerable losses in livestock (cattle, sheep and goats) and wildlife (antelopes, giraffes, lions, and cheetahs) through reproductive disorders such as abortions and stillbirths. Q fever and toxoplasmosis testing in South Africa is conducted by the Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR). However, both zoonoses are understudied and not monitored in South Africa as they are not considered controlled or notifiable diseases in the Animal Disease Act 35 of 1984. A retrospective study was conducted on Q fever (2007-2009) and toxoplasmosis (2007-2017) using diagnostic laboratory data at the ARC-OVR. Also, we report on sporadic abortion and stillbirth cases in livestock from diagnostic tissue samples submitted for Coxiella burnetii polymerase chain reaction (PCR) detection at the ARC-OVR.

Results: During 2007 to 2009, 766 animal samples were tested for C. burnetii antibodies and seropositivity was 0.9% (95%CI: 0.3-1.7) with sheep (1.9%; 95%CI: 0.6-4.4) having the highest seropositivity followed by cattle (0.7%; 95%CI: 0.09-2.6), while all goats (0.0%; 95%CI: 0.0-4.2) and wildlife (0.0%; 95%CI: 0.0-2.5) tested were negative. From 2007 to 2017, 567 sera were tested for T. gondii antibodies; overall seropositivity was 12.2% (95%CI: 9.6-15). Wildlife had highest seropositivity to T. gondii antibodies (13.9%; 95%CI: 9.0-19.7) followed by goats (12.9%; 95%CI: 9.2-17.4) and sheep (12.3%; 95%CI: 5.1-23.8) while seropositivity in cattle was 2.4% (95%CI: 0.06-12.9). Of 11 animals tested by C. burnetii PCR detection (2021-2022), 10 (91.0%) were positive. The amplicon sequences showed similarity to Coxiella burnetii strain 54T1 transposase gene partial coding sequence.

Conclusions: We have confirmed the occurrence of the causative agents of Q fever and toxoplasmosis in livestock and wildlife in South Africa, with data limitations. These zoonoses remain of importance with limited information about them in South Africa. This study provides baseline information for future studies on Q fever and toxoplasmosis in South African livestock and wildlife, as well other African countries. Due to limited data collection experienced in this study, it is recommended that improvements in data collection samples tested should include associated factors such as sex, age, and breed of the animals.

Keywords: Diagnostic laboratory data; PCR detection; Retrospective study; Risk factors; Seropositivity.

Fig. 1

Map of South African provinces showing origins of sera tested for Q fever (2007–2009) and toxoplasmosis (2007- 2017) serology testing

Fig. 2

Detection of C. burnetii in diagnostic tissue sample by IS1111 PCR. The first lane is Quick-Load® 100 bp DNA Ladder (New England Biolabs, Massachusetts, USA). The Coxiella gene fragment (gblock) from Integrated DNA Technologies (IDT, Iowa, USA) was used as template positive control while distilled water used as template negative control in the reaction. The blank is an empty unloaded lane. Samples 2271(a), 2271(b), 5269, 5030, 12,072(a), 12,072(b), 4234, 4322(a), 4322(b), 4322(c), 4322(d), 4460(a), 4460(b), 6450, 6451(a) and 6451(b)are diagnostic tissue samples submitted for C. burnetii PCR detection at Bacterial PCR laboratory, ARC-OVR