Prevalence and occupational exposure to zoonotic diseases in high-risk populations in the Free State Province, South Africa

Abstract

IntroductionZoonotic diseases are responsible for 2.5 billion human cases globally and approximately 2.7 million deaths annually. Surveillance of animal handlers and livestock for zoonotic pathogens contributes to understanding the true disease burden and risk factors within a community. This study investigated the prevalence of selected zoonoses in cattle, farm workers and occupational exposure to endemic zoonotic diseases and their associated risk factors.MethodsSputum samples from farmworkers were screened for Mycobacterium bovis. Blood specimens from farmworkers and archived sera were tested for serological evidence of Brucella sp., hantaviruses, and Leptospira sp. Communal and commercial cattle herds were tested for bovine tuberculosis and brucellosis.ResultsMycobacterium bovis was not isolated from human samples. A total of 327 human sera were screened, and 35/327 (10.7%) were Brucella sp. IgG positive, 17/327 (5.2%) Leptospira sp. IgM positive, and 38/327 (11.6%) hantavirus IgG positive (95% CI). A higher proportion of Brucella sp. IgG-positive samples were detected among veterinarians (value of p = 0.0006). Additionally, two cattle from a commercial dairy farm were bovine tuberculosis (bTB) positive using the bTB skin test and confirmatory interferon-gamma assay. A higher percentage of confirmed brucellosis-positive animals were from communal herds (8.7%) compared to commercial herds (1.1%).DiscussionThese findings highlight the brucellosis and M. bovis prevalence in commercial and communal herds, the zoonotic disease risk in commercial and subsistence farming in developing countries, and the occupational and rural exposure risk to zoonotic pathogens.

Oxidative Synthesis of Bioactive B‐3 Analogue of Procyanidin with 3,4‐cis Stereochemistry

“…The Synthesis of 4-arylflavan-3-ols from flavan-3,4-diol precursors, which established that the corresponding 2,3-trans-3,4-trans diastereoisomers are considered more stable than the corresponding 2,3-trans-3,4-cis isomers, supports the experimental result. [37] Furthermore, the diastereoisomers of the 4-arylflavan-3-ols are distinguished using the 1H NMR coupling constants of C-ring resonances. The characteristic coupling constants for 2,3-trans-3,4-trans isomers are J 2,3 = 10 Hz and J 3,4 = 8.5-9.8 Hz, respectively, [37] which is in agreement with Compound 15 with J 3,4 = 8.8 Hz and compound 20 J 3,4(C) = 8.6 Hz.…”

“…[37] Furthermore, the diastereoisomers of the 4-arylflavan-3-ols are distinguished using the 1H NMR coupling constants of C-ring resonances. The characteristic coupling constants for 2,3-trans-3,4-trans isomers are J 2,3 = 10 Hz and J 3,4 = 8.5-9.8 Hz, respectively, [37] which is in agreement with Compound 15 with J 3,4 = 8.8 Hz and compound 20 J 3,4(C) = 8.6 Hz.…”

“…Records have revealed empirically established CD rules for 4-arylflavan-3-ols predict a positive Cotton effect at 240 nm with β-configuration at C-4 and a negative Cotton effect at the same wavelength with α-configuration. [9,[37][38][39] Subsequent catalytic hydrogenation gave the first synthetic access to the free phenolic 2,3-trans-3,4-cis-4arylflavan-3-ol 16. Acetylation of the compound yielded the corresponding acetylated compound 17 (Scheme 2).…”

Identification and molecular characterization of Mycobacterium bovis DNA in GeneXpert® MTB/RIF ultra-positive, culture-negative sputum from a rural community in South Africa

“…While sputum samples, traditionally employed for pulmonary TB diagnosis, are not ideal for M. bovis detection due to its predilection for extrapulmonary disease, instances of its presence in sputum and lymph nodes are not uncommon [ 4 , 13 , 15 , 37 , 38 ], especially in high-risk areas with HIV and TB co-prevalence and endemic M. bovis in wildlife and livestock, like many low and middle-income African countries [ 14 , 15 , [39] , [40] , [41] ]. These studies hypothesize that viable M. bovis in human respiratory samples may result from inhalation of bacilli-laden aerosols during direct contact with infected animals (including carcasses), exposure to contaminated environments, or consumption of contaminated food like unpasteurized milk or cheese [ 6 , 8 , [42] , [43] , [44] ].…”

“…It is important to note that most international TB surveillance programs, including those in SA's rural communities, often do not employ culture medium or incubation times optimal for the growth of M. bovis and may not routinely collect extra-pulmonary samples for evaluation [ 11 , 12 ]. Remarkably, to date, in SA there have been no documented reports of M. bovis in people [ 13 ]. This observation is indeed perplexing, especially when considering increased reports of M. bovis infections in people from at-risk communities in neighbouring African countries [ 14 , 15 ], the high prevalence of HIV/AIDS among SA populations, the well-established presence of M. bovis in SA wildlife and livestock, and the recent surge in environmental reports documenting its presence in wastewater [ 16 ].…”