Characterizing epidemiological and genotypic features of Mycobacterium bovis infection in wild dogs (Lycaon pictus)

Mycobacterium bovis (M. bovis) infects a wide range of wildlife species and has recently been discovered in the endangered African wild dog (Lycaon pictus). This study aimed to characterize the epidemiology of tuberculosis (TB) in wild dogs in endemic areas of South Africa. We describe 12 TB cases in wild dogs from Kruger National Park (KNP), Hluhluwe–iMfolozi Park (HiP) and a private facility in Hoedspruit from 2015 to 2017. Spoligotyping was used to identify the disease-causing M. bovis strain in these cases, and whole-genome sequencing was performed on 5 M. bovis isolates (KNP = 2 and HiP = 3) to investigate genomic diversity as well as the relationship to other isolates found in these geographical areas. Three distinct strain types were responsible for the M. bovis infections in this species. The SB0121 strain was observed in wild dogs from KNP, whereas SB0130 was responsible for infection in wild dogs from HiP. A novel strain, SB2681, was also identified in the HiP wild dogs. Whole-genome sequence analysis suggests that different infection sources exist among these wild dogs and that inter-species transmission most likely occurred between wildlife predators and prey located within shared geographical areas. This study highlights the importance of regular disease surveillance to identify and characterize potential threats for successful control of infection and protection of endangered species.The South African Medical Research Council and the National Research Foundation.http://wileyonlinelibrary.com/journal/tbedhj2022Paraclinical Science

Development of gene expression assays measuring immune responses in the spotted hyena (Crocuta crocuta)

As scavengers, spotted hyenas (Crocuta crocuta) are exposed to a wide array of pathogens but exhibit low mortality rates due to infectious disease. This suggests that this species exhibits a unique and robust immune response to pathogens. However, few tools exist to measure cell-mediated immunity (CMI) in hyenas and we aimed to develop a gene expression assay to quantify antigen-specific responses. Whole blood from five Mycobacterium bovis-sensitised hyenas was incubated in Nil and TB antigen tubes of the QuantiFERON®-TB Gold (QFT) system. Using qPCR, the relative expression stability of the reference genes ACTB, GAPDH, YWHAZ and TBP in these samples was determined as well as the mean fold change in the expression of IFNG, CXCL8, CXCL9, CXCL10 and CXCL11 in M. bovis-antigen stimulated blood. The expression of YWHAZ and TBP showed greatest stability, and YWHAZ was selected as a reference for further analysis. The expression of CXCL9 and CXCL11 showed greatest upregulation in antigen-stimulated blood and the assay results for these genes were strongly correlated. The measurement of antigen-induced CXCL9 and CXCL11 expression, relative to that of YWHAZ, can be used to measure CMI responses to infectious diseases in spotted hyenas.Keywords: bovine tuberculosis (bTB), cell-mediated immunity (CMI), CXC chemokine, Mycobacterium bovis, relative qPCR, YWHA

Development of gene expression assays measuring immune responses in the spotted hyena (<i>Crocuta crocuta</i>)

<p>As scavengers, spotted hyenas (<i>Crocuta crocuta</i>) are exposed to a wide array of pathogens but exhibit low mortality rates due to infectious disease. This suggests that this species exhibits a unique and robust immune response to pathogens. However, few tools exist to measure cell-mediated immunity (CMI) in hyenas and we aimed to develop a gene expression assay to quantify antigen-specific responses. Whole blood from five <i>Mycobacterium bovis</i>- sensitised hyenas was incubated in Nil and TB antigen tubes of the QuantiFERON®-TB Gold (QFT) system. Using qPCR, the relative expression stability of the reference genes <i>ACTB</i>, <i>GAPDH</i>, <i>YWHAZ</i> and <i>TBP</i> in these samples was determined as well as the mean fold change in the expression of <i>IFNG</i>, <i>CXCL8</i>, <i>CXCL9</i>, <i>CXCL10</i> and <i>CXCL11</i> in <i>M. bovis</i>-antigen stimulated blood. The expression of <i>YWHAZ</i> and <i>TBP</i> showed greatest stability, and <i>YWHAZ</i> was selected as a reference for further analysis. The expression of <i>CXCL9</i> and <i>CXCL11</i> showed greatest upregulation in antigen-stimulated blood and the assay results for these genes were strongly correlated. The measurement of antigen-induced <i>CXCL9</i> and <i>CXCL11</i> expression, relative to that of <i>YWHAZ</i>, can be used to measure <i>CMI</i> responses to infectious diseases in spotted hyenas.</p

Mycobacterium bovis Infection in African wild dogs, Kruger National Park, South Africa

We screened African wild dogs (Lycaon pictus) in Kruger National Park, South Africa, for Mycobacterium bovis infection using an interferon-gamma release assay. We detected M. bovis sensitization in 20 of 21 packs; overall apparent infection prevalence was 83%. These animals experience high infection pressure, which may affect long-term survival and conservation strategies.The South African government through the South African Medical Research Council and the National Research Foundation of South Africa.http://wwwnc.cdc.gov/eidam2020Veterinary Tropical Disease