Q fever and toxoplasmosis in South African livestock and wildlife: A retrospective study on seropositivity and sporadic abortion, and on 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 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 (antelopes, giraffes, lions, and cheetahs) (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 (antelopes, giraffes, lions, and cheetahs) 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 %) tested positive by IS1111 PCR. The study confirmed the first presence of C. burnetii and T. gondii in various provinces of South Africa, which can pave pave way for future epidemiological studies Conclusions: More studies on Q fever and toxoplasmosis are needed in different provinces of South Africa to be able to implement effective control measures for the two zoonoses. It is recommended that improvements in data collection on the samples tested should include associated factors such as sex, age, and breed of the animals.

Serological Evidence and Coexposure of Selected Infections among Livestock Slaughtered at Eastern Cape Abattoirs in South Africa

“…According to studies, consuming raw or undercooked beef and milk increases the risk of contracting zoonotic infections including T. gondii [81]. It was reported in South Africa by Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVI) that, between 2007 and 2017, only 567 animal samples had been submitted for toxoplasmosis tests, further indicating the negligence of this zoonotic disease surveillance [35].…”

“…Te sample size was calculated using the following formula: n = z 2 P exp Q/L2, where n is the sample size, P exp is the expected prevalence, L is the precision of the estimate (also called "the allowable error" or margin of error) which is equal to half the width of the confdence interval, Q = 1 − P exp , and Z is the (1 − α 2 ) percentile of a standard normal distribution [45]; for α = 0.05, Z = 1.96. Due to lack of recent data on seropositivity of Brucella spp., T. gondii, and C. burnetii in cattle, sheep, and pigs in Eastern Cape Province, 11% prevalence was used based on recent data from other provinces in South Africa to determine the sample size [11,35]. Tis provided the sample size of 151 for each species which meets the required sample size per the calculation, except for the porcine samples as fewer pig animals were received by the abattoirs during the sampling period.…”

“…Toxoplasmosis is an under-reported parasitic infection in Africa [34]. Tere are limited studies on toxoplasmosis in SA; however, seropositive animals (cattle, sheep, and cats) have been reported [35].…”