Bovine tuberculosis at the human-livestock-wildlife interface and its control through one health approach in the Ethiopian Somali Pastoralists: A review

Macrophage polarization in lymph node granulomas from cattle and pigs naturally infected with Mycobacterium tuberculosis complex

Tuberculosis in animals is caused by members of the Mycobacterium tuberculosis complex (MTC), with the tuberculous granuloma being the main characteristic lesion. The macrophage is the main cell type involved in the development of the granuloma and presents a wide plasticity ranging from polarization to classically activated or pro-inflammatory macrophages (M1) or to alternatively activated or anti-inflammatory macrophages (M2). Thus, this study aimed to analyze macrophage polarization in granulomas from cattle and pig lymph nodes naturally infected with MTC. Tuberculous granulomas were microscopically categorized into four stages and a panel of myeloid cells (CD172a/calprotectin), M1 macrophage polarization (iNOS/CD68/CD107a), and M2 macrophage polarization (Arg1/CD163) markers were analyzed by immunohistochemistry. CD172a and calprotectin followed the same kinetics, having greater expression in late-stage granulomas in pigs. iNOS and CD68 had higher expression in cattle compared with pigs, and the expression was higher in early-stage granulomas. CD107a immunolabeling was only observed in porcine granulomas, with a higher expression in stage I granulomas. Arg1+ cells were significantly higher in pigs than in cattle, particularly in late-stage granulomas. Quantitative analysis of CD163+ cells showed similar kinetics in both species with a consistent frequency of immunolabeled cells throughout the different stages of the granuloma. Our results indicate that M1 macrophage polarization prevails in cattle during early-stage granulomas (stages I and II), whereas M2 phenotype is observed in later stages. Contrary, and mainly due to the expression of Arg1, M2 macrophage polarization is predominant in pigs in all granuloma stages.

Tuberculosis in wild animals in India

India is renowned for its complex megadiverse ecosystems and abundant biodiversity. Bovine tuberculosis (bTB) often remains synonymous with Mycobacterium bovis infection in cattle. The domain of tuberculosis (TB) among wild animals, induced by members of the Mycobacterium tuberculosis complex organisms (MTBC), is often underexplored and underreported in India. Within this context, instances of wild animal tuberculosis (wTB) have manifested across both captive and free-roaming animals. The sources contributing to wTB in animals can be human, animal, or environmental factors, thus illuminating the complex transmission pathways. The diagnosis of wTB continues to pose a formidable challenge, a consequence of the expansive taxonomic diversity in both the host and the pathogen. Complications inherent in acquiring samples from wildlife, the absence of standardized diagnostic protocols, limited insights into infection prevalence, and resource constraints compound diagnosis. Amidst these, adopting the comprehensive One Health paradigm surfaces as an imperative, accentuating the interconnectedness bridging human, animal, and environmental health. Recognizing key stakeholders and fostering intersectoral collaboration to provide enhanced diagnostic techniques driven by skilled personnel and advanced infrastructure play pivotal roles in a comprehensive strategy. Additionally, leveraging vaccination efforts contributes to effective control. A national wTB surveillance program is a cornerstone, ensuring an integrated and holistic approach to disease management. Through this review, we delve into the current landscape of wTB in India, unveiling its multifaceted challenges, and further explore the multifarious strategies that the One Health approach proffers in this dynamic endeavor.

Proteomic analysis of granulomas from cattle and pigs naturally infected with Mycobacterium tuberculosis complex by MALDI imaging

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has recently gained prominence for its ability to provide molecular and spatial information in tissue sections. This technology has the potential to uncover novel insights into proteins and other molecules in biological and immunological pathways activated along diseases with a complex host-pathogen interaction, such as animal tuberculosis. Thus, the present study conducted a data analysis of protein signature in granulomas of cattle and pigs naturally infected with the Mycobacterium tuberculosis complex (MTC), identifying biological and immunological signaling pathways activated throughout the disease. Lymph nodes from four pigs and four cattle, positive for the MTC by bacteriological culture and/or real-time PCR, were processed for histopathological examination and MALDI-MSI. Protein identities were assigned using the MaTisse database, and protein-protein interaction networks were visualized using the STRING database. Gene Ontology (GO) analysis was carried out to determine biological and immunological signaling pathways in which these proteins could participate together with Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Distinct proteomic profiles between cattle and pig granulomas were displayed. Noteworthy, the GO analysis revealed also common pathways among both species, such as "Complement activation, alternative pathway" and "Tricarboxylic acid cycle", which highlight pathways that are conserved among different species infected by the MTC. In addition, species-specific terms were identified in the current study, such as "Natural killer cell degranulation" in cattle or those related to platelet and neutrophil recruitment and activation in pigs. Overall, this study provides insights into the immunopathogenesis of tuberculosis in cattle and pigs, opening new areas of research and highlighting the importance, among others, of the complement activation pathway and the regulation of natural killer cell- and neutrophil-mediated immunity in this disease.

Impact of infectious diseases on wild bovidae populations in Thailand: insights from population modelling and disease dynamics

The wildlife and livestock interface is vital for wildlife conservation and habitat management. Infectious diseases maintained by domestic species may impact threatened species such as Asian bovids, as they share natural resources and habitats. To predict the population impact of infectious diseases with different traits, we used stochastic mathematical models to simulate the population dynamics over 100 years for 100 times in a model gaur (Bos gaurus) population with and without disease. We simulated repeated introductions from a reservoir, such as domestic cattle. We selected six bovine infectious diseases; anthrax, bovine tuberculosis, haemorrhagic septicaemia, lumpy skin disease, foot and mouth disease and brucellosis, all of which have caused outbreaks in wildlife populations. From a starting population of 300, the disease-free population increased by an average of 228% over 100 years. Brucellosis with frequency-dependent transmission showed the highest average population declines (-97%), with population extinction occurring 16% of the time. Foot and mouth disease with frequency-dependent transmission showed the lowest impact, with an average population increase of 200%. Overall, acute infections with very high or low fatality had the lowest impact, whereas chronic infections produced the greatest population decline. These results may help disease management and surveillance strategies support wildlife conservation.

Unveiling insights into bovine tuberculosis: A comprehensive review

The frequent zoonotic disease known as "bovine tuberculosis" is brought on by the Mycobacterium bovis bacteria, which can infect both people and animals. The aim of this review article is to provide an explanation of the etiology, history, epidemiology, pathogenesis, clinical symptoms, diagnosis, transmission, risk factors, public health importance, economic impact, treatment, and control of bovine tuberculosis. Primarily, bovine tuberculosis affects cattle, but other animals may also be affected. Bovine tuberculosis is present throughout the world, with the exception of Antarctica. Cattle that contract bovine tuberculosis might suffer from a persistent, crippling illness. In the early stages of the disease, there are no symptoms. The tuberculin test is the primary method for detecting bovine tuberculosis in cows. Depending on its localized site in the infected animal, M. bovis can be found in respiratory secretions, milk, urine, feces, vaginal secretions, semen, feces, and exudates from lesions (such as lymph node drainage and some skin lesions). This illness generally lowers cattle productivity and could have a negative financial impact on the livestock business, particularly the dairy industry. The most effective first-line anti-tuberculosis chemotherapy consists of isoniazid, ethambutol, rifampin, and streptomycin. Second-line drugs used against bovine tuberculosis include ethionamide, capreomycin, thioacetazone, and cycloserine. To successfully control and eradicate bovine tuberculosis, developed nations have implemented routine testing and culling of infected animals under national mandatory programs.

Mapping Bovine Tuberculosis in Colombia, 2001-2019

INTRODUCTION

Bovine tuberculosis is a zoonotic disease of significant impact, particularly in countries where a pastoral economy is predominant. Despite its importance, few studies have analysed the disease's behaviour in Colombia, and none have developed maps using geographic information systems (GIS) to characterise it; as such, we developed this study to describe the temporal-spatial distribution of bovine tuberculosis in Colombia over a period of 19 years.

METHODS

A retrospective cross-sectional descriptive study, based on reports by the Colombian Agricultural Institute (ICA), surveillance of tuberculosis on cattle farms in Colombia from 2001 to 2019 was carried out. The data were converted into databases using Microsoft Access 365®, and multiple epidemiological maps were generated with the QGIS® version 3.36 software coupled to shape files of all the country's departments.

RESULTS

During the study period, 5273 bovine tuberculosis cases were identified in multiple different departments of Colombia (with a mean of 278 cases/year). Regarding its temporal distribution, the number of cases varied from a maximum of 903 cases (17.12% of the total) in 2015 to a minimum of 0 between 2001 and 2004 and between 2017 and 2019 (between 2005 and 2016, the minimum was 46 cases, 0.87%).

CONCLUSIONS

GIS are essential for understanding the temporospatial behaviour of zoonotic diseases in Colombia, as is the case for bovine tuberculosis, with its potential implications for the Human and One Health approaches.

Prioritization of zoonoses for multisectoral, One Health collaboration in Somalia, 2023

Background

The human population of Somalia is vulnerable to zoonoses due to a high reliance on animal husbandry. This disease risk is exacerbated by relatively low income (poverty) and weak state capacity for health service delivery in the country as well as climate extremes and geopolitical instability in the region. To address this threat to public health efficiently and effectively, it is essential that all sectors have a common understanding of the priority zoonotic diseases of greatest concern to the country.

Methods

Representatives from human, animal (domestic and wildlife), agriculture, and environmental health sectors undertook a multisectoral prioritization exercise using the One Health Zoonotic Disease Prioritization (OHZDP) tool developed by the United States CDC. The process involved: reviewing available literature and creating a longlist of zoonotic diseases for potential inclusion; developing and weighting criteria for establishing the importance of each zoonoses; formulating categorical questions (indicators) for each criteria; scoring each disease according to the criteria; and finally ranking the diseases based on the final score. Participants then brainstormed and suggested strategic action plans to prevent, and control prioritized zoonotic diseases.

Results

Thirty-three zoonoses were initially considered for prioritization. Final criteria for ranking included: 1) socioeconomic impact (including sensitivity) in Somalia; 2) burden of disease in humans in Somalia); 3) availability of intervention in Somalia; 4) environmental factors/determinants; and 5) burden of disease in animals in Somalia. Following scoring of each zoonotic disease against these criteria, and further discussion of the OHZDP tool outputs, seven priority zoonoses were identified for Somalia: Rift Valley fever, Middle East respiratory syndrome, anthrax, trypanosomiasis, brucellosis, zoonotic enteric parasites (including Giardia and Cryptosporidium), and zoonotic influenza viruses.

Conclusions

The final list of seven priority zoonotic diseases will serve as a foundation for strengthening One Health approaches for disease prevention and control in Somalia. It will be used to: shape improved multisectoral linkages for integrated surveillance systems and laboratory networks for improved human, animal, and environmental health; establish multisectoral public health emergency preparedness and response plans using One Health approaches; and enhance workforce capacity to prevent, control and respond to priority zoonotic diseases.

Unraveling the epidemiology of Mycobacterium bovis using whole-genome sequencing combined with environmental and demographic data

When studying the dynamics of a pathogen in a host population, one crucial question is whether it transitioned from an epidemic (i.e., the pathogen population and the number of infected hosts are increasing) to an endemic stable state (i.e., the pathogen population reached an equilibrium). For slow-growing and slow-evolving clonal pathogens such as Mycobacterium bovis, the causative agent of bovine (or animal) and zoonotic tuberculosis, it can be challenging to discriminate between these two states. This is a result of the combination of suboptimal detection tests so that the actual extent of the pathogen prevalence is often unknown, as well as of the low genetic diversity, which can hide the temporal signal provided by the accumulation of mutations in the bacterial DNA. In recent years, the increased availability, efficiency, and reliability of genomic reading techniques, such as whole-genome sequencing (WGS), have significantly increased the amount of information we can use to study infectious diseases, and therefore, it has improved the precision of epidemiological inferences for pathogens such as M. bovis. In this study, we use WGS to gain insights into the epidemiology of M. bovis in Cameroon, a developing country where the pathogen has been reported for decades. A total of 91 high-quality sequences were obtained from tissue samples collected in four abattoirs, 64 of which were with complete metadata. We combined these with environmental, demographic, ecological, and cattle movement data to generate inferences using phylodynamic models. Our findings suggest M. bovis in Cameroon is slowly expanding its epidemiological range over time; therefore, endemic stability is unlikely. This suggests that animal movement plays an important role in transmission. The simultaneous prevalence of M. bovis in co-located cattle and humans highlights the risk of such transmission being zoonotic. Therefore, using genomic tools as part of surveillance would vastly improve our understanding of disease ecology and control strategies.

Geo-epidemiology of animal tuberculosis and Mycobacterium bovis genotypes in livestock in a small, high-incidence area in Sicily, Italy

Introduction

The persistence of animal tuberculosis (TB) in livestock is a major concern in Sicily, Italy. The objective of this study was to elucidate the transmission dynamics of M. bovis infection in a highly circumscribed, and at the same time geographically diverse, high-risk area of the island through an in-depth geo-epidemiological investigation of TB in cattle and black pigs raised in small-scale extensive farms across the district of Caronia.

Methods

We used genotype analysis coupled with geographic information system (GIS) technology and phylogenetic inference to characterize the spatial distribution of TB and M. bovis genotypes in livestock and the genetic relationships between M. bovis isolates. A total of 589 M. bovis isolates collected from slaughtered cattle (n = 527) and Sicilian black pigs (n = 62) over a 5-year period (2014–2018) were included in the study.

Results

TB was widespread throughout the district and was most frequent in the north-central area of the district, especially along one of the district’s streams. We identified a total of 62 M. bovis genotypes. Identical genetic profiles were isolated from both neighboring and non-neighburing herds. The 10 most frequent genotypes, accounting for 82% of M. bovis isolates, showed geographic specificities in that they tended to cluster in specific spatial niches. The landscape structure of these niches—i.e. steep slopes, rocky ridges, meadows and streams—is likely to have had a significant influence on the distribution of TB among livestock in Caronia. Higher concentrations of TB were observed along streams and in open meadows, while rocky ridges and slopes appeared to have hampered the spread of TB.

Discussion

The geographical distribution of TB cases among livestock in Caronia is consistent with several epidemiological scenarios (e.g., high density of infected herds along the streams or in hilly plateau where livestock share pastures). Landscape structure is likely to play an important role in the transmission and persistence of M. bovis infection across the district. Additional potential risk factors, such as livestock trading and extensive breeding methods, are also discussed. Our results will contribute to the improvement of surveillance, control and eradication activities of TB in Sicily by the implementation of ad hoc TB control measures, especially in farms located along streams, sharing common pastures or with mixed animal species.

Applications of environmental DNA (eDNA) in agricultural systems: Current uses, limitations and future prospects

Global food production, food supply chains and food security are increasingly stressed by human population growth and loss of arable land, becoming more vulnerable to anthropogenic and environmental perturbations. Numerous mutualistic and antagonistic species are interconnected with the cultivation of crops and livestock and these can be challenging to identify on the large scales of food production systems. Accurate identifications to capture this diversity and rapid scalable monitoring are necessary to identify emerging threats (i.e. pests and pathogens), inform on ecosystem health (i.e. soil and pollinator diversity), and provide evidence for new management practices (i.e. fertiliser and pesticide applications). Increasingly, environmental DNA (eDNA) is providing rapid and accurate classifications for specific organisms and entire species assemblages in substrates ranging from soil to air. Here, we aim to discuss how eDNA is being used for monitoring of agricultural ecosystems, what current limitations exist, and how these could be managed to expand applications into the future. In a systematic review we identify that eDNA-based monitoring in food production systems accounts for only 4 % of all eDNA studies. We found that the majority of these eDNA studies target soil and plant substrates (60 %), predominantly to identify microbes and insects (60 %) and are biased towards Europe (42 %). While eDNA-based monitoring studies are uncommon in many of the world's food production systems, the trend is most pronounced in emerging economies often where food security is most at risk. We suggest that the biggest limitations to eDNA for agriculture are false negatives resulting from DNA degradation and assay biases, as well as incomplete databases and the interpretation of abundance data. These require in silico, in vitro, and in vivo approaches to carefully design, test and apply eDNA monitoring for reliable and accurate taxonomic identifications. We explore future opportunities for eDNA research which could further develop this useful tool for food production system monitoring in both emerging and developed economies, hopefully improving monitoring, and ultimately food security.

Development of a monoclonal antibodies-based interferon-gamma enzyme-linked immunosorbent assay (ELISA) for rapid and accurate diagnosis of bovine tuberculosis.. [DOI: 10.21203/rs.3.rs-1918522/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Bovine tuberculosis is an infectious and chronic disease affecting cattle, caused by Mycobacterium bovis (M. bovis). The zoonotic nature of the disease has a serious worldwide impact on human health. Also, the significant economic costs caused by such disease in addition to the deficiency of precise estimate of the actual disease prevalence necessitate more efficient detection and control measures, particularly in developing countries. The main target of the present work was to develop a local, less expensive bovine tuberculosis interferon-gamma ELISA (Bo-IFN-γ ELISA) kit for the rapid and accurate diagnosis of bovine tuberculosis. In the current study, three murine hybridomas producing monoclonal antibodies (mAbs) against bovine interferon-gamma (Bo-IFN-γ) were developed and their monoclonal antibodies were characterized. The produced mAbs were of IgM isotype and its specificity was proved using the western blot technique. The prepared mAbs were used for the development of the bovine IFN- γ ELISA test that was evaluated for laboratory diagnosis of bovine tuberculosis. The sensitivity and specificity of the developed ELISA kit as compared with the standard tuberculin skin test was determined. This method is based on the measurement of IFN-γ released from sensitized bovine lymphocytes upon exposure to the mycobacterial antigens. Using checkerboard titration, the optimal coating concentration of anti- Bo-IFN-γ was 20µg/well. Blood samples from apparently healthy cattle proved negative in the tuberculin test were examined with the developed kit and the cut-off value (COV) was equal to 0.30 optical density (OD). In a preliminary study for evaluation of the sensitivity and specificity of the developed ELISA, 23 cattle were examined with both the Bo-IFN-γ ELISA and the standard tuberculin skin test. The developed Bo-IFN-γ ELISA showed high sensitivity (98%) and specificity (71.4%) in the diagnosis of bovine tuberculosis as compared to the standard tuberculin skin test.

Prevalence and Molecular Characterization of Mycobacterium bovis in Slaughtered Cattle Carcasses in Burkina Faso; West Africa

This cross-sectional study was conducted at the slaughterhouses/slabs of Oudalan and Ouagadougou in Burkina Faso, between August and September 2013. It aimed at determining the prevalence of bovine tuberculosis (bTB) suggestive lesions in slaughtered cattle carcasses and to identify and characterize the mycobacteria isolated from these lesions. A thorough postmortem examination was conducted on carcasses of a total of 2165 randomly selected cattle. The overall prevalence of bTB suggestive lesions was 2.7% (58/2165; 95% CI 2.1–3.5%). Due to the low number of positive samples, data were descriptively presented. The lesions were either observed localized in one or a few organs or generalized (i.e., miliary bTB) in 96.6% (n = 57) and 3.4% (n = 2), respectively. The identified mycobacteria were M. bovis (44.4%, n = 20), M. fortuitum (8.9%, n = 4), M. elephantis (6.7%, n = 3), M. brumae (4.4%, n = 2), M. avium (2.2%, n = 1), M. asiaticum (2.2%, n = 1), M. terrae (2.2%, n = 1), and unknown non-tuberculous mycobacteria (NTM) (11.1%, n = 5). Moreover, eight mixed cultures with more than one Mycobacterium species growing were also observed, of which three were M. bovis and M. fortuitum and three were M. bovis and M. elephantis. In conclusion, M. bovis is the predominant causative agent of mycobacterial infections in the study area. Our study has identified a base to broaden the epidemiological knowledge on zoonotic transmission of mycobacteria in Burkina Faso by future studies investigating further samples from humans and animals, including wild animals employing molecular techniques.

The Role of Histopathology as a Complementary Diagnostic Tool in the Monitoring of Bovine Tuberculosis

The diagnosis of bovine tuberculosis (bTB) is based on the single intradermal tuberculin test (SIT), interferon gamma, and compulsory slaughter of reactor animals. Culture and PCR from fresh tissue are regarded as gold standard techniques for post-mortem confirmation, with the former being time-consuming and presenting moderate to low sensitivity and the latter presenting promising results. Histopathology has the advantage to identify and categorize lesions in both reactor and non-reactor animals. Therefore, this study aims to highlight the role of histopathology in the systematic diagnosis of bTB to shorten the time to disclose positive animals. Blood (212) and lymph node (681) samples were collected for serological, bacteriological, and histopathological analyses from a total of 230 cattle subjected to the Spanish bTB eradication program. Seventy-one lymph nodes and 59 cattle yielded a positive result to bacteriology, with 59 lymph nodes and 48 cattle presenting a positive result in real-time PCR from fresh tissue. Roughly 19% (40/212) of sera samples gave a positive result to ELISA. Tuberculosis-like lesions (TBLs) were observed in 11.9% (81/681) of the lymph nodes and 30.9% (71/230) of cattle. Noteworthy, TBLs were evidenced in 18 out of 83 SIT⁻ and real-time PCR and bacteriology negative animals, with 11/18 disclosing a positive result to Ziehl-Neelsen technique and two of them to ddPCR from paraffin blocks targeting IS6110. Six out of these 11 ZN⁺ corresponded with mesenteric LN and were confirmed positive to paratuberculosis. Histopathology yielded a sensitivity of 91.3% (CI₉₅ 83.2–99.4%) and a specificity of 84.4% (CI₉₅ 78.6–89.3%) with good agreement (κ = 0.626) when compared with real-time PCR. Our results confirm that histopathology allows a rapid confirmation of real-time PCR and bacteriology, emphasizing its contribution to bTB control and monitoring.

γδ T cells in artiodactyls: Focus on swine

Vaccination is the most effective medical strategy for disease prevention but there is a need to improve livestock vaccine efficacy. Understanding the structure of the immune system of swine, which are considered a γδ T cell "high" species, and thus, particularly how to engage their γδ T cells for immune responses, may allow for development of vaccine optimization strategies. The propensity of γδ T cells to home to specific tissues, secrete pro-inflammatory and regulatory cytokines, exhibit memory or recall responses and even function as antigen-presenting cells for αβ T cells supports the concept that they have enormous potential for priming by next generation vaccine constructs to contribute to protective immunity. γδ T cells exhibit several innate-like antigen recognition properties including the ability to recognize antigen in the absence of presentation via major histocompatibility complex (MHC) molecules enabling γδ T cells to recognize an array of peptides but also non-peptide antigens in a T cell receptor-dependent manner. γδ T cell subpopulations in ruminants and swine can be distinguished based on differential expression of the hybrid co-receptor and pattern recognition receptors (PRR) known as workshop cluster 1 (WC1). Expression of various PRR and other innate-like immune receptors diversifies the antigen recognition potential of γδ T cells. Finally, γδ T cells in livestock are potent producers of critical master regulator cytokines such as interferon (IFN)-γ and interleukin (IL)-17, whose production orchestrates downstream cytokine and chemokine production by other cells, thereby shaping the immune response as a whole. Our knowledge of the biology, receptor expression and response to infectious diseases by swine γδ T cells is reviewed here.

A study on clinical diagnosis of tuberculosis in free ranging and captive wild animals of India

Background

Tuberculosis (TB) is a disease of paramount importance at the wildlife-livestock-human interface.

Aims

To study the occurrence and Mycobacterium (M) species involved in the TB of free-ranging and captive wild animals in various Indian states.

Methods

A total of 396 clinical samples from 207 different wild animal species from various Indian national parks, zoological gardens, etc., were analyzed by lateral flow assay (LFA), Ziehl-Neelsen (ZN) staining, and PCR. Clinical samples include blood (n=156), faecal swabs (n=103), serum (n=73), and nasal swabs or trunk wash fluids (n=64).

Results

Clinical signs of TB were absent in 202 animals, although 21 wild animals were seropositive for pathogenic Mycobacterium antigens by LFA. Clinical signs like progressive weight loss, and respiratory distress were exhibited by 4 sloth bears (Melursus ursinus) and an elephant (Elephas maximus), which were also found positive for LFA, PCR, and ZN staining. ZN staining showed positivity for acid-fast bacilli (AFB) in 9 (8.74%) faecal and 9 (14.06%) nasal swabs or trunk wash fluids of sloth bears (7 samples) and elephants (2 samples). M. tuberculosis was detected in 7 sloth bears and 2 elephants, whereas M. bovis was found in a spotted deer (Axis axis) by species-specific PCR.

Conclusion

The circulation of TB organisms in wild animals warrants a strict surveillance programme to identify the carrier status of these animals so that effective TB control strategies can be formulated.

Genomic characterization of Wenzhou mammarenavirus detected in wild rodents in Guangzhou City, China

Wenzhou mammarenavirus (WENV) is a zoonotic pathogen newly discovered in east and southeast Asia. WENV has been found in wild rodent animals around the world while its standing is barely understood in Guangzhou city, where is known as a region of outbreak hotspot for zoonotic emerging infectious diseases. To investigate the prevalence and genomic characteristics of mammarenavirus in Guangzhou City, lung tissue samples from wild rodent species were collected from five districts of Guangzhou City in the year 2015 and 2016. The viral RNA was extracted and then subjected to mammarenavirus-specific PCR. The result revealed approximately 1.0% (3/306) nucleic acid positivity for lung tissue samples obtained from three rodent species: Mus musculus, Rattus flavipectus, and Rattus norvegicus. Viral metagenomic sequencing of three samples was then carried out and two full segment L and three full segment S sequences were obtained. Phylogenetics analysis indicated the sequences of the new mammarenavirus strain have 76.2% - 94.4% similarity to known WENV encoded genes, with the highest similarity to the WENV 9-24 strain. Population structure analysis grouped all known WENV into seven lineages, and this WENV Guangzhou strain was grouped with WENV 9-24 as well. Though the seroprevalence result was not available, our data provides the first nucleic acid evidence of circulating WENV in Guangzhou city, and it suggested WENV had a broader host tropism than previously known.

Modeling the spatial distribution of anthrax in southern Kenya

BACKGROUND

Anthrax is an important zoonotic disease in Kenya associated with high animal and public health burden and widespread socio-economic impacts. The disease occurs in sporadic outbreaks that involve livestock, wildlife, and humans, but knowledge on factors that affect the geographic distribution of these outbreaks is limited, challenging public health intervention planning.

METHODS

Anthrax surveillance data reported in southern Kenya from 2011 to 2017 were modeled using a boosted regression trees (BRT) framework. An ensemble of 100 BRT experiments was developed using a variable set of 18 environmental covariates and 69 unique anthrax locations. Model performance was evaluated using AUC (area under the curve) ROC (receiver operating characteristics) curves.

RESULTS

Cattle density, rainfall of wettest month, soil clay content, soil pH, soil organic carbon, length of longest dry season, vegetation index, temperature seasonality, in order, were identified as key variables for predicting environmental suitability for anthrax in the region. BRTs performed well with a mean AUC of 0.8. Areas highly suitable for anthrax were predicted predominantly in the southwestern region around the shared Kenya-Tanzania border and a belt through the regions and highlands in central Kenya. These suitable regions extend westwards to cover large areas in western highlands and the western regions around Lake Victoria and bordering Uganda. The entire eastern and lower-eastern regions towards the coastal region were predicted to have lower suitability for anthrax.

CONCLUSION

These modeling efforts identified areas of anthrax suitability across southern Kenya, including high and medium agricultural potential regions and wildlife parks, important for tourism and foreign exchange. These predictions are useful for policy makers in designing targeted surveillance and/or control interventions in Kenya. We thank the staff of Directorate of Veterinary Services under the Ministry of Agriculture, Livestock and Fisheries, for collecting and providing the anthrax historical occurrence data.

Prevention and control of COVID-19 in pastoral community through One Health Approach

The vast majority of its population being a pastoralist community, the Somali region in Ethiopia shares the longest border with its neighboring east African countries. These communities face a high risk for transmission of imported COVID-19 cases and remain vulnerable due to lack of access to health delivery and low utilisation of services. Valuable lessons from other countries, has placed the One Health Approach as an appropriate, feasible and applicable preventive and control measure for COVID-19. This paper discusses the epidemiological and social susceptibility of pastoral communities in the transmission of COVID-19 and the introduction of One Health Approach as an effective inter-disciplinary response and management.

Estimates of the global and continental burden of animal tuberculosis in key livestock species worldwide: A meta-analysis study

Zoonotic animal tuberculosis (TB) is a One Health paradigm infectious disease, caused by Mycobacterium tuberculosis complex bacteria, that affects different host species with varying levels of management. In most developed countries, official surveillance and control strategies support the longitudinal reporting of herd and/or animal prevalence. However, for under resourced countries without surveillance plans, this information may be obtained from cross-sectional studies only. The objective of this meta-analysis was to perform a worldwide estimate of the overall prevalence of animal TB in different livestock species whose importance in production systems varies according to the region of the world. The ISI's Web of Science and Google Scholar were searched combining keywords and related database-specific subject terms to identify relevant cohort or cross-sectional work published in this topic. A total of 443 articles were retrieved, screened, and a final set of 182 references included. Potential sources of variation were investigated using subgroup analyses and meta-regression. Prevalence estimates in five mammalian host groups were stratified according to host species, host characteristics, anatomical localization of lesions, sample size, geographical location, and diagnostic tests. The multivariable meta-regression analysis accounted for a range between 0% (farmed wild boar) and 68.71% (camelids) of the overall observed heterogeneity, indicating that the pondered predictors partially explain the observed variability. Differences in the overall prevalence of TB across hosts were small, with most groups showing values around 10%, except farmed wild boar (41%). The sample size emerged as an important moderator, with small size studies leading to the overestimation of prevalence. TB prevalence rates were very heterogeneous across continents and depended on the host, with lower values (below 10%) in Africa and Asia, while North America (33.6%, cattle), Europe (51%, goats), and South America (85.7%, pigs) exhibited higher rates, possibly related to greater densities of specific host groups managed on more intensive production systems. Stratification by diagnostic tests evidenced heterogeneous prevalence rates depending on the host group, possibly reflecting differences in test performance across different hosts. Results from this study highlight different TB burden scenarios, pinpointing host groups and diagnostics that should be prioritized in surveillance systems in different regions, thus providing policy-relevant information to catalyse TB control in settings with lower installed capacity and better resource allocation at the human-animal-environment interface.

Multidrug-resistant strains of Mycobacterium complex species in Egyptian farm animals, veterinarians, and farm and abattoir workers

Background and Aim:

Mycobacterium tuberculosis complex (MTBC) is a group of mycobacteria that are important human pathogens. Mycobacterium tuberculosis and Mycobacterium bovis cause serious chronic life-threatening disease and also significant economic losses in both production and remedication. Recently, emergence of multidrug-resistant tuberculosis (MDR-TB) complex has generated global recognition of the need for rapid and sensitive diagnosis and development of new treatments. The current study illustrates the isolation/identification of MTBC strains in specimens obtained from cows and humans by conventional and real-time polymerase chain reaction (RT-PCR) techniques. Further, the study assesses sensitivity to antituberculosis drugs in isolated MDR strains.

Materials and Methods:

A total of 1464 samples from cattle (1285 raw milk and 179 lymph node), and 149 human sputum samples, were collected from farms and abattoirs in Delta Egypt. Conventional methods (culture and Ziehl–Neelsen staining) were implemented as were RT-PCR using MTBC universal DNA. The effect of some antituberculosis drugs on obtained isolates was assayed using drug susceptibility proportion and qualitative suspension techniques.

Results:

The MBTC detection rate using the culture method was higher than for Ziehl–Neelsen staining; raw cow milk (2.56 vs. 1.63%), lymph nodes (51.59 vs. 48.04%), and human sputum (5.36 vs. 4.02%). A total of 135 isolates were obtained. Application of RT-PCR detected 138 isolates from the same set of samples. MBTC isolates were resistant to first-line antituberculosis drugs, such as pyrazinamide, isoniazid, rifampicin, and ethambutol by 78.5, 59.3, 40.7, and 31.8%, respectively, and could be highly resistant to kanamycin (82.3%) and amikacin (80.7%). However, isolates remained sensitive to ciprofloxacin (71.1%) and clarithromycin (73.3%) as second-line drugs.

Conclusion:

There is a growing risk for isolation of MDR-TB from raw milk and lymph nodes of field tuberculin positive cattle as well as sputum of veterinarians and workers existed in farms and abattoirs. PCR-based techniques have become the gold standard for the identification of mycobacterial species, showing high efficiency compared to bacteriological and microscopic examination. Application of the first- and second-line antituberculosis drugs in combination could counter the MDR-TB concern once infections are identified.

Short report on implications of Covid-19 and emerging zoonotic infectious diseases for pastoralists and Africa

Many emerging and re-emerging zoonotic infectious diseases occur in Africa. These are projected to increase as human-animal host contact increases owing to increasing environmental degradation that shrinks nature habitats for wildlife over the continent. The current outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) responsible for causing coronavirus disease in 2019 (COVID-19) has reinvigorated discourse on the disruptiveness of the zoonotic emerging infectious diseases, owing to their transboundary character. Even as the world focuses on the COVID-19 sweeping pandemic, the Middle East respiratory syndrome coronavirus (MERS)-CoV re-emerged in Saudi Arabia infecting 18 people with five deaths; this has barely received any attention. This outbreak is particularly of concern to the pastoralists in the Horn of Africa, a region that has in recent past seen an increase in camel trade with the Gulf States, especially Yemen and Saudi Arabia. Emerging and re-emerging zoonotic infectious diseases are complex, depend on human-animal-environment interaction and pose a strain on public health systems. There is a need to address these diseases dynamically through a synergistic approach, drawing on expertise from diverse sectors. One Health approach has distinguished itself as an integrative action able to bring together multiple actors on a global, national and local scale to advance the attainment of optimal health outcomes for people, animals and the environment. One Health works by strengthening the preparedness, response, mitigation and monitoring of zoonotic infectious disease risks collaboratively. We opine that as zoonotic emerging and re-emerging infectious diseases continue to rise over pastoral Africa, comprehensive implementation of the One Health approach will be urgently required.