Molecular epidemiology of human and animal tuberculosis in Ibadan, Southwestern Nigeria

Mycobacteriosis in slaughter pigs from South Africa from 1991 to 2002: Mycobacterium spp. diversity and Mycobacterium avium complex genotypes

Introduction

Mycobacterium avium complex (MAC) bacteria are the most prominent etiological agents of lymphadenitis in pigs. M. avium subspecies hominissuis (MAH) is a member of MAC and has been reported in many parts of the world to be the most prevalent non-tuberculous mycobacteria (NTM) to cause mycobacteriosis in humans, mainly in children. Thus, the economic and zoonotic impact of MAC species are increasingly being recognized. In South Africa, little is known about the distribution of NTM and the molecular epidemiology of M. avium in pigs.

Materials and methods

In this study, lymph nodes including mandibular, mesenteric, submandibular, and retropharyngeal, with tuberculosis-like lesions were collected during routine meat inspection of slaughter pigs with no disease symptoms (n = 132), between 1991 and 2002. These pigs were slaughtered at 44 abattoirs distributed across seven of the nine South African provinces. Mycobacterial culture, polymerase chain reaction (PCR), and sequencing of the Mycobacterium specific 577 bp 16S rRNA gene fragment were performed for species and subspecies identification.

Results

The majority of the isolates (each per sample); 114 (86.4%) were identified as MAH, 8 (6%) as MAA/M. avium subsp. silvaticum, 4 (3%) were Mycobacterium tuberculosis, 2 (1.5%) as Mycobacterium intracellulare, and 1 (0.75%) as Mycobacterium bovis. The other isolates were identified as Mycobacterium lentiflavum (0.75%), Mycobacterium novocastrense (0.75%), and a Micrococcus spp. (0.75%). Using an eight-marker MLVA typing tool, we deciphered at least nine MIRU VNTR INMV types of MAH and MAA.

Discussion

Identification of known zoonotic mycobacteria, including MAH, MAA, M. intracellulare, M. bovis, and M. tuberculosis, from slaughter pigs has a potential public health impact and also strengthens recognition of the potential economic impact of MAC. This study has also for the first time in South Africa, revealed MAC MIRU VNTR INMV genotypes which will aid in the future epidemiological investigation of MAC in South Africa.

Systematic review and meta-analysis of tuberculosis in animals in Nigeria

Animal tuberculosis (TB) is a contagious and chronic disease caused by mycobacteria belonging to theMycobacterium tuberculosis complex (MTBC) in domestic and wild animals. MTBC strains infection has been confirmed in many animal species in Nigeria, including captive wildlife, cattle, dromedary camels, goats, and pigs. Despite widespread infection and the potential impact of the disease on public health, active surveillance and control strategies are absent in Nigeria. This study aimed to conduct the first comprehensive meta-analysis to assess the distribution of tuberculosis and analyze the potential moderators of infection in animals in Nigeria. Eligible studies (sixty-one (Cadmus et al., 2014) [61] prevalence and seven (Menzies and Neill, 2000) [7] case reports) were retrieved and included in the analysis. The analyses showed an overall pooled TB prevalence of 7.0% (95% CI: 6.0-8.0) comprising of infection distributed in cattle (8.0%, 95% CI: 7.0-8.0), goats (0.47%, 95% CI: 0-1.2), sheep (0.27%, 95% CI: 0.14-0.46), camels (13.0%, 95% CI: 0-47), and wildlife (13.0%, 95% CI: 9-16) respectively. The occurrence of infection was significantly moderated by the publication periods, geographical location, sample size, and detection methods. TB prevalence was heterogeneous across several predictors, with the year of publication exhibiting a higher rate (46%) of the detected heterogeneity. These findings should provide policy-relevant information to guide the design and establishment of prevention and control measures amenable to the local situations in Nigeria.

Genotyping of Mycobacterium tuberculosis complex isolated from humans and animals in northeastern Iran

The objective of this study was to genotype Mycobacterium tuberculosis complex isolated from humans and cattle in northern Iran. Over the course of one year, a total of 120 human and 21 cattle isolates were tested using region of difference (RD)-based polymerase chain reaction (PCR) and mycobacterial interspersed repetitive unites-variable number tandem repeats (MIRU-VNTR). In M. tuberculosis, out of 120 isolates investigated, the most common genotype detected was NEW-1 (53.3%), followed by CAS/ Delhi (24.1%), Haarlem (5%), Beijing (4.16%), Uganda I (4.16%), S (3.3%), Ural (0.83%), TUR (0.83%), Uganda II (0.83%), Lam (0.83%) and Cameroon (0.83%). The HGDI rate was 0.9981 and the clustering rate was 10.83. Of the isolates, QUB26 had the highest allele diversity (h: 0.76), while the loci Mtub29 and MIRU24 had the lowest (h: 0). In M. Bovis, out of 123 collected tissue samples, 21 (17%) grew on culture media. The HGDI rate was 0.71 and clustering rate was 85.7%. The locus ETRC had the highest allele diversity (h: 0.45). The findings of this study suggest that there is high genetic diversity among M. tuberculosis isolates in Khorasan Razavi Province, which is consistent with similar results from other studies in other provinces in Iran and neighboring countries. This indicates that the prevalent genotypes in this study are spreading in the Middle East region. Furthermore, considering that M. Bovis isolates were identified in two clusters, it seems that all of them have a common origin and are circulating among the livestock farms in the province.

Research progress on distribution and exposure risk of microbial aerosols in animal houses

Environmental aerosols in animal houses are closely related to the productive performance and health level of animals living in the houses. Preferable housing environments can improve animal welfare and production efficiency, so it is necessary to monitor and study these environments. In recent years, there have been many large-scale outbreaks of respiratory diseases related to biological aerosols, especially the novel coronavirus that has been sweeping the world. This has attracted much attention to the mode of aerosol transmission. With the rapid development of large-scale and intensive breeding, microbial aerosols have gradually become the main factor of environmental pollution in animal houses. They not only lead to a large-scale outbreak of infectious diseases, but they also have a certain impact on the health of animals and employees in the houses and increase the difficulty of prevention and control of animal-borne diseases. This paper reviews the distribution, harm, and control measures of microbial aerosols in animal house environments in order to improve people's understanding of them.

Mycobacterium tuberculosis sensu stricto in African Apes, What Is Its True Health Impact?

Since the Symposium on Mycobacterial Infections of Zoo Animals held at the National Zoological Park, Smithsonian Institution in 1976, our understanding of tuberculosis (TB) in non-domestic animals has greatly expanded. Throughout the past decades, this knowledge has resulted in improved zoo-habitats and facilities design, stricter biosecurity measures, and advanced diagnostic methods, including molecular techniques, that have significantly decreased the number of clinical disease caused by Mycobacterium tuberculosis in apes under human care settings. In the other hand, exponential growth of human populations has led to human encroachment in wildlife habitat which has resulted in increased inter-species contact and recurrent conflict between humans and wild animals. Although it is widely accepted that non-human primates are susceptible to M. tb infection, opinions differ with regard to the susceptibility to develop disease amongst different taxa. Specifically, some authors suggest that African apes are less susceptible to clinical tuberculosis than other species of primates. The aim of this review article is to evaluate the current scientific literature to determine the actual health impact of disease caused by Mycobacterium tuberculosis and more specifically Mycobacterium tuberculosis sensu stricto in African apes. The literature review included literature databases: Web of Science, Pubmed, Scopus, Wiley, Springer and Science direct, without temporal limit and proceedings of annual conferences in the field of wildlife health. Our general inclusion criteria included information about serological, molecular, pathological (macroscopic and/or microscopic), and clinical evidence of TB in African apes; while our, our more stringent inclusion selection criteria required that in addition to a gross pathology, a molecular test confirmed Mycobacterium tuberculosis sensu stricto as the cause of disease or death. We identified eleven reports of tuberculosis in African apes; of those, only four reports met the more stringent selection criteria that confirmed M. tb sensu stricto in six individuals. All reports that confirmed M. tb sensu stricto originated from zoological collections. Our review suggests that there is little evidence of disease or mortality caused by M. tb in the different species of African apes both under human care and free ranging populations. Additional studies are needed in free-ranging, semi-captive populations (sanctuaries) and animals under human care (zoos and rescue centers) to definitely conclude that this mycobacteria has a limited health effect in African ape species.

Global prevalence of Mycobacterium bovis infections among human tuberculosis cases: Systematic review and meta-analysis

Tuberculosis (TB) is a chronic communicable bacterial disease caused by Mycobacterium tuberculosis complex (MTBC) species. M. tuberculosis is the main causative agent of human TB, and cattle are the primary host of Mycobacterium bovis; due to close interaction between cattle and humans, M. bovis poses a zoonotic risk. This review summarizes and estimates the prevalence of M. bovis infection among human cases. Studies reporting TB prevalence data that were published in English during 10 years from 20 April 2009 to 17 April 2019 were identified through search of PubMed and other sources. Quality of studies and risk of bias were assessed using standard tools for prevalence study reports. Characteristics of included studies and their main findings were summarized in tables and discussed with narrative syntheses. Meta-analysis was performed on 19 included studies, with a total of 7,185 MTBC isolates identified; 702 (9.7%) of them were characterized as of subspecies M. bovis, but there was a large prevalence difference between the studies, ranging from 0.4% to 76.7%. The genotyping-based studies reported significantly lower prevalence of zoonotic TB than did the studies based on older techniques. The overall pooled prevalence of M. bovis aggregated from all included studies was 12.1% of the total MTBC isolates, while the corresponding pooled figure from the 14 genotyping-based studies was only 1.4%. Generally, human M. bovis cases reported from different countries of the world suggest that the impact of zoonotic TB is still important in all regions. However, it was difficult to understand the true picture of the disease prevalence because of methodological differences. Future investigations on zoonotic TB should carefully consider these differences when evaluating prevalence results.

Serological detection of Mycobacterium Tuberculosis complex infection in multiple hosts by One Universal ELISA

Tuberculosis (TB), a contagious disease mainly caused by Mycobacterium tuberculosis (M. tb), Mycobacterium bovis (M. bovis), and Mycobacterium caprae (M. caprae), poses a major global threat to the health of humans and many species of animals. Developing an ante-mortem detection technique for different species would be of significance in improving the surveillance employing a One Health strategy. To achieve this goal, a universal indirect ELISA was established for serologically detecting Mycobacterium tuberculosis complex infection for multiple live hosts by using a fusion protein of MPB70, MPB83, ESAT6, and CFP10 common in M. tb, M. bovis, and M. caprae as the coating antigen (MMEC) and HRP-labeled fusion protein A and G as a secondary antibody. After testing the known positive and negative sera, the receiver operating characteristic curves were constructed to decide the cut-off values. Then, the diagnostic sensitivity and specificity of MMEC/AG-iELISA were determined as 100.00% (95% CI: 96.90%, 100.00%) and 100.00% (95% CI: 98.44%, 100.00%) for M. bovis infection of cattle, 100.00% (95% CI: 95.00%, 100.00%) and 100.0% (95% CI: 96.80%, 100.00%) for M. bovis infection of sheep, 90.74% (95% CI: 80.09%, 95.98%) and 98.63% (95% CI: 95.14%, 99.76%) for M. bovis infection of cervids, 100.00% (95% CI: 15.81%, 100.00%) and 98.81% (95% CI: 93.54%, 99.97%) for M. bovis infection of monkeys, 100.00% (95% CI: 86.82%, 100.00%) and 94.85% (95% CI: 91.22%, 97.03%) for M. tb infection of humans. Furthermore, this MMEC/AG-iELISA likely detects M. caprae infection in roe deer. Thus this method has a promising application in serological TB surveillance for multiple animal species thereby providing evidence for taking further action in TB control.

Genetic evaluation of Mycobacteriumbovis isolates with MIRU-VNTR and spoligotyping

Background/aim

Determining the epidemiological characteristics of M. bovis strains isolated from human and animal tuberculosis cases will assist in taking more appropriate and effective control measures in controlling tuberculosis originating from animals.

Materials and methods

In this study, 32 M. bovis isolates of animal origin and 10 of human origin were isolated and identified in the Çukurova region between March 2011 and June 2012. The 12-locus MIRU-VNTR and spoligotyping methods were used.

Results

Six different patterns were determined by spoligotyping and 10 by MIRU-VNTR. When both methods were used together, the number of patterns was found to be 28; MIRU4, MIRU26, MIRU31, and MIRU40 had the highest locus discrimination powers by MIRU-VNTR. The isolates concentrated in the SB0120 pattern at the rate of 42.85% in spoligotyping. By the same method, it was seen that 7 isolates were M bovis ssp. caprae pattern and 2 human isolates were M. bovis BCG pattern. Nevertheless, spoligotyping and MIRU-VNTR patterns showed that 5 M. bovis isolates of human origin were 100% compatible with isolates originating from cattle.

Conclusion

In this study, we determined that the use of spoligotyping and MIRU-VNTR methods together was found to be more sensitive in the epidemiological analysis of M. bovis isolates.

Reverse zoonotic tuberculosis transmission from an emerging Uganda I strain between pastoralists and cattle in South-Eastern Nigeria

Background

Tuberculosis remains a major public health challenge globally with increasing risks for inter-transmission between pastoralists and cattle in Nigeria. This study was aimed at using molecular tools to establish zoonotic transmission of tuberculosis between pastoralists and their cattle in Ebonyi State, Nigeria. Sputum (n = 149) and milk (n = 144) samples from pastoralists and cattle, respectively were screened on the assumption of subclinical infections considering unguarded human-livestock interactions. Isolates obtained were analysed using deletion typing, spoligotyping and 24-Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats (MIRU-VNTR).

Results

Fifty-four MTC were confirmed by deletion typing and were differentiated accordingly (M. tuberculosis: pastoralists =42, cattle = 2; M. bovis: pastoralists =1; M. africanum: pastoralists =9). Spoligotyping indicated 59.2% Uganda I/SIT46 (pastoralists =28; cattle = 1), 16.3% Latin American Mediterranean/SIT61 (pastoralists =8), 2.0% T/SIT53 (pastoralists =1) strains of M. tuberculosis and new strains of M. bovis and M. africanum. The 24-MIRU-VNTR of selected predominant cluster isolates shared by cattle and pastoralists (Uganda I/SIT46: pastoralists =9; cattle = 1) showed the same number of copies at each of the repetitive loci.

Conclusions

Mycobacterium bovis was confirmed in humans and a reverse zoonotic tuberculosis transmission from an emerging Uganda I M. tuberculosis strain between pastoralists and cattle in Nigeria evidenced by MIRU-VNTR. Using molecular tools will help mitigate disease burden through informed epidemiological insights.

Viral infection detection using metagenomics technology in six poultry farms of eastern China

With rapidly increasing animal pathogen surveillance requirements, new technologies are needed for a comprehensive understanding of the roles of pathogens in the occurrence and development of animal diseases. We applied metagenomic technology to avian virus surveillance to study the main viruses infecting six poultry farms in two provinces in eastern China. Cloacal/throat double swabs were collected from 60 birds at each farm according to a random sampling method. The results showed that the method could simultaneously detect major viruses infecting farms, including avian influenza virus, infectious bronchitis virus, Newcastle disease virus, rotavirus G, duck hepatitis B virus, and avian leukemia virus subgroup J in several farms. The test results were consistent with the results from traditional polymerase chain reaction (PCR) or reverse transcription-PCR analyses. Five H9N2 and one H3N8 avian influenza viruses were detected at the farms and were identified as low pathogenic avian influenza viruses according to HA cleavage sites analysis. One detected Newcastle disease virus was classified as Class II genotype I and avirulent type according to F0 cleavage sites analysis. Three avian infectious bronchitis viruses were identified as 4/91, CK/CH/LSC/99I and TC07-2 genotypes by phylogenetic analysis of S1 genes. The viral infection surveillance method using metagenomics technology enables the monitoring of multiple viral infections, which allows the detection of main infectious viruses.

Genetic diversity of Mycobacterium tuberculosis complex strains isolated from livestock workers and cattle in Nigeria

Molecular typing techniques are useful in understanding tuberculosis epidemiology; yet, they have been under-utilised at the human-animal interface in Nigeria. Sixty-four Mycobacterium tuberculosis complex (MTBC) isolates including 42 M. tuberculosis, 13 M. bovis and nine M. africanum obtained from livestock workers (LW, n = 47) and their cattle (n = 17) in three geographical zones of Nigeria were genotyped to identify and evaluate the genetic diversity of the circulating MTBC using spoligotyping. Distribution into clades of M. tuberculosis revealed; 45.3% Uganda I- [SIT46- cattle: 1; LW: 28], 14.1% Latin American Mediterranean- [SIT61, cattle: 1; LW: 8], and 1.6% T- [SIT53—LW: 1]. The M. bovis strains were 6.3% SB0944 [cattle: 4] and 1.6% each of SB0300, SB1026, SB1027 and SB1439 [cattle: 4]. Seventeen MTBC isolates [cattle: 7; LW: 10] yielded 14 new spoligotype patterns including three M. tuberculosis strains (three isolates), five M. bovis strains (five isolates) and six M. africanum strains (nine isolates), two of which belonged to MAF1. Only few families namely, the not previously described Uganda I-, LAM and SB0944 are predominant among the LW and cattle, with other types in lower prevalences. The strain population structure indicates an intriguing diversity and possible zoonotic linkage with consequences for TB control in the country. The need to employ newer molecular techniques such as Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats and whole genome sequence to decipher circulating MTBC strains in Nigeria is advocated.

Isolation of Mycobacterium tuberculosis from livestock workers and implications for zooanthroponotic transmission in Ibadan, South-western Nigeria

Introduction

Tuberculosis (TB) remains a public health problem in sub-Saharan Africa coupled with dearth of information about the disease among livestock workers at risk of infection. We determined the prevalence of pulmonary TB infection and factors associated with its occurrence among livestock workers in south-western Nigeria.

Methods

A cross-sectional study was conducted using active case-finding among livestock workers with sub-clinical pulmonary TB between August 2014 and March 2015. Sputum samples were cultured and subjected to a two-step multiplex-PCR technique based on genus-typing and genomic regions-of-difference. Interviewer-administered questionnaire was utilized in assessing worker’s TB related knowledge and practices. Data were analysed using STATA 12.

Results

Overall, 206 livestock workers (traders = 136; butchers = 70) were screened; 5.1% (7/136) of the traders and 7.1% (5/70) of the butchers had positive mycobacterial cultures. Molecular techniques identified one Mycobacterium tuberculosis with six non-tuberculous mycobacteria (NTM) from the traders and four M. tuberculosis with one NTM from the butchers.Participants within the age range of 50 years and above were at higher risk of being infected with TB (OR = 7.7; 95%CI:1.7-35.6) and majority had poor knowledge and practices regarding TB.

Conclusions

We confirmed M. tuberculosis as the cause of pulmonary TB among the livestock workers, with implications for zooanthroponotic transmission of the disease along the human-animal ecosystem interface in Nigeria.

Tuberculosis in dromedary camels slaughtered in Nigeria: a documentation of lesions at postmortem

In comparison with other livestock, tuberculosis (TB) in camels has not been extensively studied in Nigeria. Camels in the hands of Nigerian pastoralists share the livestock ecosystem and are increasingly becoming an important component of the sector. This study was designed to investigate the occurrence of TB lesions and animal-level risk of infection in slaughtered camel carcasses in one of the public abattoirs in Nigeria, from June to August 2016. A total of 212 camel carcasses comprising 82.5% (175/212) males and 17.5% (37/212) females were examined for tuberculous lesions. Of the carcasses examined, 33.5% (71/212) had TB lesions. The occurrence of lesions was most significantly associated with poor body condition (OR = 0.249; CI 0.134-0.454 [p < 0.001]). Distribution among anatomical sites of macroscopic lesions in the infected camels revealed three different pathological patterns as pulmonary (n = 51), abdominal (n = 11), and disseminated (n = 9) forms. Higher prevalence of gross TB lesions in camel carcasses highlights eminent threats to both animal and public health, pointing to an already existing risk of intra- and inter-species transmission of infection.

The most common spoligotype of Mycobacterium bovis isolated in the world and the recommended loci for VNTR typing; A systematic review

Mycobacterium bovis is a neglected zoonotic organism that epidemiological studies are of crucial importance in identifying its source, control it and prevent it from spreading. The aim of this study was to investigate the most common spoligotypes of Mycobacterium bovis circulating around the world and introduce the most and least strong determine powers of loci for VNTR. We have used different databases such as ISC, science direct, Embase (Elsevier), Web of Science, Scopus and Medline via PubMed. Searches were performed by key words including: Mycobacterium bovis, MIRU -VNTR, spoligotyping and discrimination power. Finally, thirty-one articles were selected after filtering out some titles, abstracts and full texts. Spoligotype SB0120 was the most common circulating type on several continents while SB0121 existed in Europe, Africa and America. SB0140 was also detected in Asia, Europe and America. QUB3232 and QUB11b were more appropriate loci among the loci with high discriminatory power. MIRU 10 and MIRU4 were among the loci with poor discriminatory power. Taking the published data into consideration, SB0120 and SB0121 are predominant spoligotypes of M. bovis circulating among animals around the world. Determining the most common spoligotype of M. bovis is the key to find source of infection, control and prevent the disease.

Mycobacterium tuberculosis complex genotypes circulating in Nigeria based on spoligotyping obtained from Ziehl-Neelsen stained slides extracted DNA

METHODS

All State TB control programmes in Nigeria were requested to submit 25-50 smear-positive Ziehl-Neelsen (ZN) stained slides for screening during 2013-2014. DNA was extracted from 929 slides for spoligotyping and drug-resistance analysis using microbead-based flow-cytometry suspension arrays.

RESULTS

Spoligotyping results were obtained for 549 (59.1%) of 929 samples. Lineage 4 Cameroon sublineage (L4.6.2) represented half of the patterns, Mycobacterium africanum (L5 and L6) represented one fifth of the patterns, and all other lineages, including other L4 sublineages, represented one third of the patterns. Sublineage L4.6.2 was mostly identified in the north of the country whereas L5 was mostly observed in the south and L6 was scattered. The spatial distribution of genotypes had genetic geographic gradients. We did not obtain results enabling the detection of drug-resistance mutations.

CONCLUSION/SIGNIFICANCE

We present the first national snapshot of the M. tuberculosis spoligotypes circulating in Nigeria based on ZN slides. Spoligotyping data can be obtained in a rapid and high-throughput manner with DNA extracted from ZN-stained slides, which may potentially improve our understanding of the genetic epidemiology of TB.

Genetic diversity and potential routes of transmission of Mycobacterium bovis in Mozambique

Bovine tuberculosis is a zoonotic disease with largely unknown impact in Africa, with risk factors such as HIV and direct contact with animals or consumption of Mycobacterium bovis infected animal products. In order to understand and quantify this risk and design intervention strategies, good epidemiological studies are needed. Such studies can include molecular typing of M. bovis isolates. The aim of this study was to apply these tools to provide novel information concerning the distribution of bovine tuberculosis in cattle in Mozambique and thereby provide relevant information to guide policy development and strategies to contain the disease in livestock, and reduce the risk associated with transmission to humans. A collection of 178 M. bovis isolates was obtained from cattle in Mozambique. Using spoligotyping and regions of difference analysis, we classified the isolates into clonal complexes, thus reporting the first characterisation of M. bovis strains in this region. Data from MIRU-VNTR typing was used to compare isolates from a number of African countries, revealing a deeply geographically structured diversity of M. bovis. Eastern Africa appears to show high diversity, suggesting deep evolution in that region. The diversity of M. bovis in Africa does not seem to be a function of recent importation of animals, but is probably maintained within each particular region by constant reinfection from reservoir animals. Understanding the transmission routes of M. bovis in Mozambique and elsewhere is essential in order to focus public health and veterinary resources to contain bovine tuberculosis.

Bovine tuberculosis is a rather neglected zoonotic disease caused by Mycobacterium bovis that is of global concern owing to the persistence of the bacillus in reservoirs that can spread bovine tuberculosis between animals and humans. Africa remains understudied regarding this pathogen, and should be an area of concern given that in many regions the consumption of raw milk or meat from infected animals persists and the presence of HIV infection renders the population more susceptible. In order to control the disease, we need to understand M. bovis epidemiology, which includes the sources of infection. The important conclusion drawn from the work presented here is that there is a strong association between M. bovis genetic characteristics and geography. This implies that the diversity of M. bovis isolates in Mozambique does not seem to be caused by recent introductions to the territory, but is probably maintained within reservoirs in each particular region.

Prevalence and risk factors of mycobacterial infections in farm and trade cattle in southwestern Nigeria

We evaluated the prevalence of mycobacterial infections (i.e., Mycobacterium bovis and non-tuberculous mycobacteria [NTM]) and their associated risk factors among cattle herds and trade cattle in southwestern Nigeria. Through cross-sectional study design, cattle herds from three locations were screened using the single intradermal comparative cervical tuberculin test based on two diagnostic standards; more than 4 mm (˃ 4 mm) and more than 2 mm (˃ 2 mm) cut-off points. Abattoir study involved screening trade cattle for tuberculous lesions. Overall, 515 cattle from 45 herds were screened. Using > 4 mm, animal level and herd prevalence of 11.7 and 46.7% were recorded, respectively. Applying the ˃ 2 mm cut-off, animal level and herd prevalence increased to 31.1 and 60.0%, respectively. Significantly, using the ˃ 2 mm cut-off, cattle in medium size herds/extensive management system (OR = 1.6; 95% CI 1.1-2.5) and Sokoto Gudali (OR = 2.3; 95% CI 1.4-3.8) were more at risk of being positive reactors, while Rahaji (OR = 0.3; 95% CI 0.1-0.7) breeds of cattle and cows in the peri-urban area (OR = 0.4; 95% CI 0.2-0.9) were less at risk of being positive reactors. Again, M. avium reactor of 21.7% was observed. In the abattoir, 1797 cattle were examined with 126 lesions suggestive of tuberculosis (TB). Culture/molecular analyses confirmed 2.2% M. bovis and 0.9% NTM infections. Risk factors associated with bovine TB among trade cattle were sex (OR = 4.0; 95% CI 1.2-13.5) and age (OR = 0.3; 95% CI 0.1-0.9). We confirm 11.7% prevalence of mycobacterial infections among populations of cattle screened with breed and herd size being major risk factors.

Molecular epidemiology of Mycobacterium bovis in Cameroon

We describe the largest molecular epidemiological study of Bovine Tuberculosis (bTB) in a sub-Saharan African country with higher spatial resolution providing new insights into bTB. Four hundred and ninety-nine samples were collected for culture from 201 and 179 cattle with and without bTB-like lesions respectively out of 2,346 cattle slaughtered at Bamenda, Ngaoundere, Garoua and Maroua abattoirs between 2012–2013. Two hundred and fifty-five M. bovis were isolated, identified and genotyped using deletion analysis, Hain® Genotype MTBC, spoligotyping and MIRU-VNTR. African 1 was the dominant M. bovis clonal complex, with 97 unique genotypes including 19 novel spoligotypes representing the highest M. bovis genetic diversity observed in Africa to date. SB0944 and SB0953 dominated (63%) the observed spoligotypes. A third of animals with multiple lesions had multiple strain infections. Higher diversity but little evidence of recent transmission of M. bovis was more common in Adamawa compared to the North-West Region. The Adamawa was characterised by a high frequency of singletons possibly due to constant additions from an active livestock movement network compared to the North-West Region where a local expansion was more evident. The latter combined with population-based inferences suggest an unstable and stable bTB-endemic status in the North-West and Adamawa Regions respectively.

Mycobacterium tuberculosis and Dual M. tuberculosis/M. bovis Infection as the Cause of Tuberculosis in a Gorilla and a Lioness, Respectively, in Ibadan Zoo, Nigeria

Tuberculosis (TB) in zoo animals is an important public health problem in places where it occurs. This is even very important in countries where there is little public health awareness about the disease; thus confined animals in the zoo can be infected directly or indirectly by infected humans and vice versa. In Nigeria, the problem of TB is a major concern among both humans and cattle. Here, we present cases of Mycobacterium tuberculosis and M. tuberculosis/M. bovis infections in a female gorilla and a lioness, respectively, in a zoo in Ibadan, Nigeria. These cases were confirmed after bacteriological examinations and DNA from granulomatous lesions of the animals' carcasses were subjected to the Hain and spoligotyping techniques. Our findings reveal the first documented report of TB infections in a gorilla and a lioness in zoo animals in Nigeria. The public health risks of tuberculosis in zoological settings are therefore reemphasized.

Abattoir-based estimates of mycobacterial infections in Cameroon

Mycobacteria cause major diseases including human tuberculosis, bovine tuberculosis and Johne’s disease. In livestock, the dominant species is M. bovis causing bovine tuberculosis (bTB), a disease of global zoonotic importance. In this study, we estimated the prevalence of Mycobacteria in slaughter cattle in Cameroon. A total of 2,346 cattle were examined in a cross-sectional study at four abattoirs in Cameroon. Up to three lesions per animal were collected for further study and a retropharyngeal lymph node was collected from a random sample of non-lesioned animals. Samples were cultured on Lowenstein Jensen media and the BACTEC MGIT 960 system, and identified using the Hain^® Genotype kits. A total of 207/2,346 cattle were identified with bTB-like lesions, representing 4.0% (45/1,129), 11.3% (106/935), 23.8% (38/160) and 14.8% (18/122) of the cattle in the Bamenda, Ngaoundere, Garoua and Maroua abattoirs respectively. The minimum estimated prevalence of M. bovis was 2.8% (1.9–3.9), 7.7% (6.1–9.6), 21.3% (15.2–28.4) and 13.1% (7.7–20.4) in the four abattoirs respectively. One M. tuberculosis and three M. bovis strains were recovered from non-lesioned animals. The high prevalence of M. bovis is of public health concern and limits the potential control options in this setting without a viable vaccine as an alternative.

Isolation and molecular characterization of Mycobacterium tuberculosis from humans and cattle in Namwala District, Zambia

Mycobacterium tuberculosis, the causative agent of tuberculosis in humans, is considered primarily a human pathogen. It has, however, been reported in a wide range of domestic and wild animals, often living in close prolonged contact with humans. Sputum samples in which acid fast bacteria were detected in smears were collected from patients at three health facilities in Namwala district, Zambia. Samples from cattle presenting gross lesions compatible with bovine tuberculosis were collected at a local abattoir in the same district. Isolated mycobacteria were identified and genotyped using classical molecular methods. From a total of 33 isolates of M. tuberculosis detected (30 from humans and 3 from cattle), two cattle isolates shared the same spoligotype and MIRU-VNTR pattern with a human patient. This study has for the first time documented the isolation of M. tuberculosis from cattle in Zambia and provides molecular evidence of an epidemiological link between M. tuberculosis isolates from humans and cattle in Namwala district. A possible spill back of M. tuberculosis to humans cannot be excluded and therefore further studies documenting to what extent M. tuberculosis is shed in cattle milk are needed. This finding further suggests that veterinary public health measures to control human TB, should also take into account the bovine reservoir.

Mycobacterium bovis in Burkina Faso: epidemiologic and genetic links between human and cattle isolates

BACKGROUND

In sub-Saharan Africa, bovine tuberculosis (bTB) is a potential hazard for animals and humans health. The goal of this study was to improve our understanding of bTB epidemiology in Burkina Faso and especially Mycobacterium bovis transmission within and between the bovine and human populations.

METHODOLOGY/PRINCIPAL FINDINGS

Twenty six M. bovis strains were isolated from 101 cattle carcasses with suspected bTB lesions during routine meat inspections at the Bobo Dioulasso and Ouagadougou slaughterhouses. In addition, 7 M. bovis strains were isolated from 576 patients with pulmonary tuberculosis. Spoligotyping, RDAf1 deletion and MIRU-VNTR typing were used for strains genotyping. The isolation of M. bovis strains was confirmed by spoligotyping and 12 spoligotype signatures were detected. Together, the spoligotyping and MIRU-VNTR data allowed grouping the 33 M. bovis isolates in seven clusters including isolates exclusively from cattle (5) or humans (1) or from both (1). Moreover, these data (genetic analyses and phenetic tree) showed that the M. bovis isolates belonged to the African 1 (Af1) clonal complex (81.8%) and the putative African 5 (Af5) clonal complex (18.2%), in agreement with the results of RDAf1 deletion typing.

CONCLUSIONS/SIGNIFICANCE

This is the first detailed molecular characterization of M. bovis strains from humans and cattle in Burkina Faso. The distribution of the two Af1 and putative Af5 clonal complexes is comparable to what has been reported in neighbouring countries. Furthermore, the strain genetic profiles suggest that M. bovis circulates across the borders and that the Burkina Faso strains originate from different countries, but have a country-specific evolution. The genetic characterization suggests that, currently, M. bovis transmission occurs mainly between cattle, occasionally between cattle and humans and potentially between humans. This study emphasizes the bTB risk in cattle but also in humans and the difficulty to set up proper disease control strategies in Burkina Faso.

Prevalence and direct economic losses from bovine tuberculosis in makurdi, Nigeria

A retrospective study was conducted to investigate the prevalence of bovine tuberculosis and direct economic losses (DEL) from tuberculosis in cattle slaughtered in Makurdi abattoirs from 2008 to 2012, using abattoir records obtained from the Ministry of Agriculture and Natural Resources. Out of 61654 cattle slaughtered during the study period 1172 (1.90%) were positive for tuberculosis lesions. The annual prevalence of bovine tuberculosis ranges from 0.90% in 2008 to 4.04% in 2012. There was significant (P < 0.05) difference in annual prevalence of bovine tuberculosis. It was also observed that there was no seasonal difference in the prevalence of bovine tuberculosis. A total of 1935 affected organs by BTB weighing 3046.50 kg, amounting to 2.91 × 10⁶ Naira (1.82 × 10⁴ USD), were condemned within the study period. Seasonal variation in organ condemnation due to bovine tuberculosis was significantly different (Mann-Whitney U statistics = 774 × 10³, P = 0.034). It was concluded that bovine tuberculosis is prevalent in Makurdi and accounts for heavy economic losses due to condemnation of edible organs.

Characterization of Mycobacterium bovis from Humans and Cattle in Namwala District, Zambia

Tuberculosis remains a major public health problem in Zambia. While human to human transmission of Mycobacterium tuberculosis is of major importance in driving the tuberculosis epidemic, the impact of Mycobacterium bovis transmission from infected cattle is largely unknown. This cross-sectional study aimed at molecular characterization of M. bovis in humans and cattle. A total of 100 human sputum samples and 67 bovine tissues were collected and analyzed for the presence of mycobacteria. Of 65 human samples that harbored acid fast bacteria (AFB), 55 isolates were obtained of which 34 were identified as M. tuberculosis and 2 as M. bovis. AFB-positive bovine samples (n = 67) yielded 47 mycobacterial isolates among which 25 were identified as M. bovis and no M. tuberculosis was found. Among the M. bovis isolates, spoligotyping revealed a high homogeneity in genotypes circulating in Namwala district. Human and cattle isolates shared identical MIRU-VNTR genotypes, suggesting that transmission between the two hosts may occur. Therefore, this study has documented zoonotic TB in human patients in Namwala district of Zambia. However, further molecular epidemiological studies in the study area are recommended.

Overview and phylogeny of Mycobacterium tuberculosis complex organisms: implications for diagnostics and legislation of bovine tuberculosis

Members of the Mycobacterium tuberculosis complex (MTBC) cause a serious disease with similar pathology, tuberculosis; in this review, bovine tuberculosis will be considered as disease caused by any member of the MTBC in bovids. Bovine tuberculosis is responsible for significant economic loss due to costly eradication programs and trade limitations and poses a threat to both endangered and protected species as well as to public health. We here give an overview on all members of the MTBC, focusing on their isolation from different animal hosts. We also review the recent advances made in elucidating the evolutionary and phylogenetic relationships of members of the MTBC. Because the nomenclature of the MTBC is controversial, its members have been considered species, subspecies or ecotypes, this review discusses the possible implications for diagnostics and the legal consequences of naming of new species.

Current knowledge and pending challenges in zoonosis caused by Mycobacterium bovis: a review

Mycobacterium bovis is both the causative agent of bovine tuberculosis (TB) and a zoonotic pathogen. In humans, considerably fewer cases of TB are caused by M. bovis than M. tuberculosis; nevertheless, diagnostic limitations mean that currently available data on prevalence grossly underestimate the true dimension of the problem. The routes of transmission from animals to humans are well known and include direct exposure to infected animals or consumption of contaminated animal products. Application of fingerprinting tools facilitates analysis of the molecular epidemiology of M. bovis in animal-to-human and human-to-human transmission. Apart from cattle and M. bovis, other animal species and members within the M. tuberculosis complex can contribute to the zoonosis. Improvements in diagnostic techniques, application of more advanced discriminatory genotyping tools, and collaboration between veterinary and human health care researchers are key to our understanding of this zoonosis.

Experimental aerosol Mycobacterium bovis model of infection in goats

The use of animal models is essential in testing the efficacy for novel therapies against tuberculosis (TB). Calves and non-human primates are examples of large animal models currently used to test TB vaccine efficacy but these animals are difficult and very expensive to house under high containment conditions. The goat may represent an effective but less expensive alternative for testing prototype vaccines against TB. Goats are susceptible to Mycobacterium bovis, Mycobacterium caprae and Mycobacterium tuberculosis infection. Aerosolized bacteria are the most common source of natural infection in humans and the primary site of natural infection is the respiratory tract. We developed a simple procedure for infecting goats with M. bovis by aerosol exposure. After 8 and 12 weeks of infection the goats were euthanized, post-mortem analysis was performed, and all exposed animals presented TB compatible lesions in the lung and associated lymph nodes. Selected lung lesions and respiratory lymph nodes were evaluated and cultured for bacteriological and histological analysis. The present work shows a reliable new animal model of aerosol infection to be used in the understanding of TB disease and development of new therapies.

Mycobacterium bovis infections in slaughter pigs in Mubende district, Uganda: a public health concern

Background

Bovine tuberculosis (TB) caused by Mycobacterium bovis is primarily a disease of ruminants, particularly cattle (Bos primigenius) and buffalo (Syncerus caffer), and is endemic in most developing countries. To date, studies done in Uganda have documented the prevalence of M. bovis in cattle, humans and wild life, in addition to non-tuberculous mycobacteria in pigs. Pigs are increasingly becoming an important component of the livestock sector and share the human ecosystem in rural Uganda. It is therefore of public health interest that they are not a source of human infections. As a follow up to previously published findings on mycobacteria in pigs, this study was aimed at investigating the occurrence and molecular characteristics of M. bovis detected in slaughter pigs in Mubende district, Uganda. One hundred fifty mesenteric lymph nodes with lesions suggestive of mycobacterial infections were collected from approximately one thousand slaughtered pigs in Mubende district over a period of five months. The isolation and identification of M. bovis was done using conventional mycobacteriological methods. Mycobacteria belonging to the Mycobacterium tuberculosis complex (MTC) were identified to species level using deletion analysis. Molecular typing was done using Spoligotyping and MIRU-VNTR analysis. Molecular data were analysed and interpreted using MIRU-VNTR plus, SpolDB4.0 and the Mycobacterium bovis spoligo database.

Results

Of the examined animals, one boar and two sows from Madudu Sub County were infected with M. bovis which presented as lesions of a deep yellow colour and a grit-like texture in the mesenteric lymph nodes. This represents 2% (3/150) of the lymph nodes where lesions suggestive of mycobacterial infections were detected. Molecular analysis revealed that the isolates from the infected pigs showed identical MIRU-VNTR profile and spoligotype (SB1469).

Conclusions

This is the first study documenting the occurrence of M. bovis in slaughter pigs in Uganda, revealing that one in fifty slaughter pigs with suspected lesions in mesenteric lymph nodes were infected. Molecular analysis revealed that the isolates were identical, showing a spoligotype previously reported from humans and cattle in the north eastern part of the Uganda cattle corridor. This finding is of public health importance, therefore there is a need for close cooperation between medical and veterinary professionals in designing and implementing control and prevention measures that safeguard the public from this potential source of zoonotic TB in Uganda.

A molecular epidemiological and genetic diversity study of tuberculosis in Ibadan, Nnewi and Abuja, Nigeria

Background

Nigeria has the tenth highest burden of tuberculosis (TB) among the 22 TB high-burden countries in the world. This study describes the biodiversity and epidemiology of drug-susceptible and drug-resistant TB in Ibadan, Nnewi and Abuja, using 409 DNAs extracted from culture positive TB isolates.

Methodology/Principal Findings

DNAs extracted from clinical isolates of Mycobacterium tuberculosis complex were studied by spoligotyping and 24 VNTR typing. The Cameroon clade (CAM) was predominant followed by the M. africanum (West African 1) and T (mainly T2) clades. By using a smooth definition of clusters, 32 likely epi-linked clusters related to the Cameroon genotype family and 15 likely epi-linked clusters related to other “modern” genotypes were detected. Eight clusters concerned M. africanum West African 1. The recent transmission rate of TB was 38%. This large study shows that the recent transmission of TB in Nigeria is high, without major regional differences, with MDR-TB clusters. Improvement in the TB control programme is imperative to address the TB control problem in Nigeria.

Naming spoligotype patterns for the RD9-deleted lineage of the Mycobacterium tuberculosis complex; www.Mbovis.org

This www.Mbovis.org website and associated databases were initiated in response to the need of the Mycobacterium bovis molecular typing community for standardisation of nomenclature for spoligotype patterns. The purpose of the website is to provide standardised names for spoligotype patterns from strains of the RD9-deleted, lineage of the Mycobacterium tuberculosis complex. Each unique spoligotype pattern is named by 'SB' followed by a four integer number (e.g. SB0120) and the database currently records over 1400 patterns submitted by the research community over the last 9 years. The database holds information and authoritative names for spoligotype patterns from both clades of Mycobacterium africanum, M. bovis (antelope), Mycobacterium microti, Mycobacterium pinnipedii, Mycobacterium caprae and M. bovis. The history of the database is described, as well as the method for submitting new patterns to the database and the functionality of the website.