Q Fever: Seroprevalence, Risk Factors in Slaughter Livestock and Genotypes of Coxiella burnetii in South Africa.

Maruping Mangena,Peter N. Thompson,Rian Pierneef,Nomakorinte Gcebe,Abiodun A. Adesiyun

doi:10.3390/pathogens10030258

Abstract

Q fever is a neglected zoonosis in South Africa, causing significant losses in livestock and game animals through reproductive disorders. However, there are limited studies on the extent of Coxiella burnetii infections in livestock in South Africa. Further, there is also lack of knowledge about the types of C. burnetii strains that are currently circulating in the country. Therefore, a cross-sectional, abattoir-based study was conducted to determine the seroprevalence of C. burnetii and associated risk factors, and to characterize C. burnetii strains from slaughter livestock at red meat abattoirs in Gauteng, South Africa. Of the 507 animals tested, 6.9% (95% CI: 4.9–9.5%) were positive for antibodies against C. burnetii. The seroprevalence was 9.4% (31/331) in cattle, 4.3% (3/69) in sheep, and 0.9% (1/107) in pigs. Out of the 63 tissue samples from 35 seropositive animals including material from two sheep aborted fetuses from Mangaung district (Free State province), 12.7% (8/63) tested positive by IS1111 PCR. Genotyping of the eight PCR-positive tissues from eight animals by MLVA revealed two novel genotypes, not available in Coxiella MLVA databases. It is concluded that slaughter animals pose a risk of exposing abattoir and farm workers to C. burnetii in South Africa.

Highlights

Q fever is caused by the obligate intercellular bacterium, Coxiella burnetii
The pathogen belongs to gamma subdivision of Proteobacteria, order Legionellales, family Coxiellaceae and C. burnetii is the only species in the genus [1]
Due to limited data available on Q fever seroprevalence and lack of knowledge on C. burnetii strains currently circulating in South Africa, we investigated the seroprevalence and associated risk factors, and further characterized

Summary

Introduction

Q fever is caused by the obligate intercellular bacterium, Coxiella burnetii. The pathogen belongs to gamma subdivision of Proteobacteria, order Legionellales, family Coxiellaceae and C. burnetii is the only species in the genus [1]. Once the bacterium enters the phagolysosome of the eukaryotic cell, it undergoes incompletely uncharacterized life cycle forms [3,4]. These are two different morphological forms, namely large (LCVs) and small cell variants (SCVs) [5]. Large cell variants have similar characteristics as typical gram-positive bacteria during exponential growth These include distinct outer membrane, periplasmic space, cytoplasmic membrane, and diffuse nucleoid, reaching more than 1 μm in length [5]. Compared to LVCs, SCVs are smaller, 0.2 to 0.5 μm in diameter and have electron-dense, condensed chromatin, and condensed cytoplasm These SCVs are resistant to osmotic shock, oxidative stress, heat shock, sonication, and pressure, one reason that

Methods

Results

Conclusion