Prevalence of bovine tuberculosis and risk factor assessment in cattle in rural livestock areas of Govuro District in the Southeast of Mozambique

Prevalence, distribution, and risk factors of bovine tuberculosis in dairy cattle in central China

Bovine tuberculosis (bTB) is one of the priority epidemic diseases in dairy cattle in China. Continuous surveillance and evaluation of the control programs will help on improving the efficiency of bTB control policy. We designed this study to investigate both animal and herd level prevalence of bTB, as well as to determine the associated factors in dairy farms in Henan and Hubei provinces. A cross-sectional study was conducted from May 2019 to September 2020 in central China (Henan and Hubei provinces). We sampled 40 herds in Henan and six herds in Hubei via stratified systematic sampling and administrated a questionnaire consisting of 35 factors. A total of 4900 whole blood samples were collected from 46 farms, including 545 calves < six months old and 4355 cows ≥ six months old. This study demonstrated a high animal-(18.65%, 95% CI: 17.6-19.8) and herd-level (93.48%, 95%CI: 82.1-98.6) prevalence of bTB in dairy farms in central China. The Least Absolute Shrinkage and Selection Operator (LASSO) and negative binomial regression models showed that herd positivity was associated with the practice of introducing new animals (RR = 1.7, 95%CI: 1.0-3.0, p = 0.042), and changing the disinfectant water in the wheel bath at the farm entrance every three days or less (RR = 0.4, 95%CI: 0.2-0.8, p = 0.005) which reduced the odds of herd positivity. In addition, the result illustrated that testing cows with a higher age group (≥ 60 months old) (OR=1.57, 95%CI: 1.14-2.17, p = 0.006) and within the early stage of lactation (DIM=60-120 days, OR=1.85, 95%CI: 1.19-2.88, p = 0.006) and the later stage of lactation (DIM≥301 days, OR=2.14, 95%CI: 1.30-3.52, p = 0.003) could maximize the odds of detecting seropositive animals. Our results have plenty of benefit to improve bTB surveillance strategies in China and elsewhere in the world. The LASSO and the negative binomial regression models were recommended when dealing with high herd-level prevalence and high dimensional data in questionnaire-based risk studies.

Zoonotic Tuberculosis: A Neglected Disease in the Middle East and North Africa (MENA) Region

Mycobacterium bovis is the etiologic agent of bovine tuberculosis (BTB), a serious infectious disease in both humans and animals. BTB is a zoonotic disease primarily affecting cattle and occasionally humans infected through close contact with infected hosts or the consumption of unpasteurized dairy products. Zoonotic tuberculosis is strongly associated with poverty and poor hygiene, and low- and middle-income countries bear the brunt of the disease. BTB has been increasingly recognized as a growing public health threat in developing countries. However, the lack of effective surveillance programs in many of these countries poses a barrier to accurately determining the true burden of this disease. Additionally, the control of BTB is threatened by the emergence of drug-resistant strains that affect the effectiveness of current treatment regimens. Here, we analyzed current trends in the epidemiology of the disease as well as the antimicrobial susceptibility patterns of M. bovis in the Middle East and North Africa (MENA) region, a region that includes several developing countries. Following PRISMA guidelines, a total of 90 studies conducted in the MENA region were selected. Our findings revealed that the prevalence of BTB among humans and cattle varied significantly according to the population size and country in the MENA region. Most of the available studies were based on culture and/or PCR strategies and were published without including data on antimicrobial resistance and molecular typing. Our findings highlighted the paramount need for the use of appropriate diagnostic tools and the implementation of sustainable control measures, especially at the human/animal interface, in the MENA region.

Prevalence and risk factors of bovine tuberculosis in slaughtered cattle, Malawi

Bovine tuberculosis (bTB) is an infectious disease with significant socioeconomic, animal, and public health impacts. However, the prevalence of bTB remains largely unclear in Malawi due to a paucity of information. Additionally, the existence of multiple risk factors is postulated to enhance bTB transmission in animals. A cross-sectional survey to estimate the prevalence of bTB, animal characteristics and identify associated risk factors was conducted from slaughtered cattle at three major regional abattoirs (southern, central and northern regions) in Malawi. Out of a total of 1547 cattle examined, 154 (9.95%) had bTB-like lesions in various visceral organs and lymph nodes; one sample per animal was collected, processed, and cultured in the in the BACTEC Mycobacterial growth indicator tube (MGIT) 960 system. From the 154 cattle that showed tuberculous like lesions, only 112 were positive on MGIT and 87 were confirmed to have M. bovis based on multiplex PCR. Cattle from the southern region (odds ratio (OR) = 1.96, 95% CI: 1.03-3.85) and central region (OR = 2.00, 95% CI: 1.16-3.56) were more likely presented with bTB-like lesions at slaughter than from the northern region. The risk of having bTB-like lesions was higher in females (OR = 1.51, CI: 1.00-2.29), older cattle (OR = 2.17, CI: 1.34-3.37), and crossbreeds (OR = 1.67, 95% CI: 1.12-2.47) than in males, younger animals, and Malawi Zebu breed, respectively. The high prevalence of bTB is of critical concern and necessitates active surveillance and strengthening of the current control strategies under a One Health (OH) approach at the animal-human interface.

Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys

Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.

Estimation of Brucella and Mycobacterium bovis contamination in bovine milk in Africa

Background and Aim: Bovine brucellosis and tuberculosis are zoonotic bacterial diseases transmitted through the consumption of raw milk and dairy products. Many developed countries have eliminated bovine brucellosis and tuberculosis in their cattle herds, however, the diseases are still endemic in Africa. Despite the public health risk of these pathogens, the sale and consumption of unpasteurized milk are still common in some African countries. This study aimed to estimate the prevalence of Brucella and Mycobacterium bovis in bovine milk. Materials and Methods: A conceptual model for milk contamination was constructed and 1 million simulations were performed using data from published articles. Results: Brucella milk contamination was estimated at a median of 8.68% (interquartile range [IQR]: 5.95-11.97%; range: 2.41-25.16%). The median prevalence of M. bovis was estimated at 6.86% (IQR: 4.25-9.40%; range: 0.01-15.16%). Conclusion: These results indicate that there is a risk of Brucella and M. bovis transmission through the consumption of unpasteurized milk. The findings of this study highlight the need to improve the safety and quality of informally marketed milk in the region.

Risk factors associated with testing positive for tuberculosis in high-yielding Holstein cows

Tuberculosis remains a significant infectious disease of farm animals and humans worldwide. The objective of this study was to assess various risk factors associated with testing positive for bovine tuberculosis (bTB) in high-yielding Holstein cows in an intensive dry-lot dairy operation. In a retrospective observational study, 9312 records from Holstein cows from a large dairy herd in northern Mexico were used. The incidence rate of lactating cows reactor to bTB was 7.3 cases/100 cow years (95% CI = 6.7-7.9%). Multiple logistic regression models indicated that cows with total milk yield during the first lactation >10,200 kg were 1.3 times (95% confidence intervals (CI) for odds ratio (OR) = 1.2-1.6) more likely to be detected as bTB reactors than cows with total milk yield <10,200 kg (8.2 vs. 6.4%; P < 0.01). The risk of being reactor to bTB increased with x̅ total milk yield/lactation >11,500 kg (OR=2.7, 95% CI = 2.3-3.3; 10.4 vs. 4.2%) compared with cows with x̅ total milk yield/lactation <11,500 kg. Cows with >10,200 kg 305-day milk yield in the last lactation was associated (P < 0.01) with 1.3 times higher odds (95% CI for OR = 1.1-1.5) of being classed as reactors than cows with <10,200 kg. Cows with peak milk yield >48 kg were 1.9 times (95% CI for OR = 1.6-2.2) more likely to be reactor to bTB than cows with peak milk yield <48 kg (9.2 vs. 5.1%; P < 0.01). Cows with either puerperal metritis (OR = 0.07, 95% CI = 0.5-0.9) or carrying twins (OR = 0.05, 95% CI = 0.01-0.19) had a protective role for being reactor to bTB. This study showed that increased milk production was associated with a higher risk of becoming positive to tuberculin skin test in high-yielding Holstein cows.

Zoonotic Tuberculosis in Humans: Control, Surveillance, and the One Health Approach

Zoonotic tuberculosis is a reemerging infectious disease in high-income countries and a neglected one in low- and middle-income countries. Despite major advances in its control as a result of milk pasteurization, its global burden is unknown, especially due the lack of surveillance data. Additionally, very little is known about control strategies. The purpose of this review was to contextualize the current knowledge about the epidemiology of zoonotic tuberculosis and to describe the available evidence regarding surveillance and control strategies in high-, middle-, and low-income countries. We conducted this review enriched by a One Health perspective, encompassing its inherent multifaceted characteristics. We found that the burden of zoonotic tuberculosis is likely to be underreported worldwide, with higher incidence in low-income countries, where the surveillance systems are even more fragile. Together with the lack of specific political commitment, surveillance data is affected by lack of a case definition and limitations of diagnostic methods. Control measures were dependent on risk factors and varied greatly between countries. This review supports the claim that a One Health approach is the most valuable concept to build capable surveillance systems, resulting in effective control measures. The disease characteristics and suggestions to implement surveillance and control programs are discussed.

Tracing cross species transmission of Mycobacterium bovis at the wildlife/livestock interface in South Africa

BACKGROUND

Bovine tuberculosis (bTB) affects cattle and wildlife in South Africa with the African buffalo (Syncerus caffer) as the principal maintenance host. The presence of a wildlife maintenance host at the wildlife/livestock interface acting as spill-over host makes it much more challenging to control and eradicate bTB in cattle. Spoligotyping and mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) genotyping methods were performed to investigate the genetic diversity of Mycobacterium bovis (M. bovis) isolates from cattle and wildlife, their distribution and transmission at the wildlife/livestock interface in northern Kwa-Zulu Natal (KZN), South Africa.

RESULTS

SB0130 was identified as the dominant spoligotype pattern at this wildlife/livestock interface, while VNTR typing revealed a total of 29 VNTR profiles (strains) in the KZN province signifying high genetic variability. The detection of 5 VNTR profiles shared between cattle and buffalo suggests M. bovis transmission between species. MIRU-VNTR confirmed co-infection in one cow with three strains of M. bovis that differed at a single locus, with 2 being shared with buffalo, implying pathogen introduction from most probably unrelated wildlife sources.

CONCLUSION

Our findings highlight inter and intra species transmission of bTB at the wildlife/livestock interface and the need for the implementation of adequate bTB control measures to mitigate the spread of the pathogen responsible for economic losses and a public health threat.

Evolutionary analysis of Mycobacterium bovis genotypes across Africa suggests co-evolution with livestock and humans

Mycobacterium bovis is the pathogenic agent responsible for bovine tuberculosis (bTB), a zoonotic disease affecting mostly cattle, but also transmittable to humans and wildlife. Genetic studies on M. bovis allow to detect possible routes of bTB transmission and the identification of genetic reservoirs that may provide an essential framework for public health action.

We used a database with 1235 M. bovis genotypes collected from different regions in Africa with 45 new Mozambican samples. Our analyses, based on phylogeographic and population genetics’ approaches, allowed to identify two clear trends. First, the genetic diversity of M. bovis is geographically clustered across the continent, with the only incidences of long-distance sharing of genotypes, between South Africa and Algeria, likely due to recent European introductions. Second, there is a broad gradient of diversity from Northern to Southern Africa with a diversity focus on the proximity to the Near East, where M. bovis likely emerged with animal domestication in the last 10,000 years.

Diversity indices are higher in Eastern Africa, followed successively by Northern, Central, Southern and Western Africa, roughly correlating with the regional archaeological records of introduction of animal domesticates. Given this scenario M. bovis in Africa was probably established millennia ago following a concomitant spread with cattle, sheep and goat. Such scenario could translate into long-term locally adapted lineages across Africa.

This work describes a novel scenario for the spread of M. bovis in Africa using the available genetic data, opening the field to further studies using higher resolution genomic data.

We describe the genetic diversity distribution in Africa of the pathogen Mycobacterium bovis, the responsible for bovine tuberculosis, mostly present in cattle but also transmittable to other animals including humans. This diversity is geographically clustered within the African continent meaning that the genetic diversity was established through independent evolution within different areas. Higher diversity values of M. bovis are found in Eastern and Northern Africa, followed by Central Africa, with Western and Southern Africa displaying the lowest diversity. These levels of diversity correlate well with the introduction of domesticated livestock in the different regions of Africa, following their domestication in the Near East 10,000 ago. We hypothesize that M. bovis emerged in the Near East and it was carried across Africa together with domesticated animals and people that developed herding practices and biological tolerance for digesting milk in adulthood. Such scenario implies a strong evolution and co-evolution of M. bovis across Africa leading to locally adapted strains that could prove a challenge for public health actions.

Atypical granuloma formation in Mycobacterium bovis-infected calves

Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation. Characterization of granulomatous lesions of Mycobacterium bovis (M. bovis) experimentally infected cattle has helped to better understand the pathogenesis of this disease. However, few studies have described granulomas found in M. bovis naturally infected cattle. The aim of this work was to examine granulomas from Holstein-Friesian cattle naturally infected with M. bovis from a dairy basin located in the central region of Mexico. Tissue samples from thirty-two cattle with lesions suggestive of tuberculosis were collected post-mortem. Fifteen of the 32 sampled animals (46.8%) were 4 months of age or younger (calves), whereas the rest (53.2%, 17/32) were over one year old (adults). Macroscopic lesions suggestive of tuberculosis were found in the mediastinal lymph node chain of all animals (32/32). From the 1,143 granulomatous lesions that were microscopically analyzed, 34.6% (396/1143) were collected from adult animals and subsequently classified according to the nomenclature suggested by Wangoo et al., 2005. Surprisingly, lesions from calf tissues showed an atypical pattern which could not be fitted into the established developmental stages of this classification. Granulomatous lesions found in calves covered most of the affected organ, histologically showed large necrotic areas with central calcification, absence of a connective tissue capsule, and few giant cells. Also, there was a higher percentage of lesions with acid-fast bacilli (AFB) when compared to studied granulomas in adults. Growth of Mycobacterium spp was detected in 11 bacteriological tissue cultures. Genotypic identification of M. bovis was performed by DNA extraction from bacterial isolates, formalin-fixed and paraffin-embedded (FFPE) tissues and samples without bacterial isolation. M. bovis was detected by PCR in 84.3% (27/32) of the studied cases; whereas other AFB were observed in tissues of the remaining sampled animals (5/32). Our results describe atypical granuloma formation in calves 4 months of age or younger, naturally infected with M. bovis. These findings contribute to better understanding the physiopathology of M. bovis infection in cattle.

Prevalence and risk factors analysis of bovine tuberculosis in cattle raised in mixed crop-livestock farming system in Tigray region, Ethiopia

Bovine tuberculosis (BTB) is a disease of animal and public health importance in developing countries. In rural Ethiopia, there is potential for a shift in the epidemiologic of this disease driven by transformation of dairy industry. This includes gradual change from the traditional mixed crop-livestock husbandry practice to a semi-intensification system. It is therefore, essential to document the prevalence and risk factors of BTB to continuously update the designing and implementation of control and prevention strategies. Here, we present findings of a cross-sectional study on the prevalence and associated risk factors of BTB among cattle reared under mixed crop-livestock farming system in Tigray region, Ethiopia. A multistage purposive sampling approach was used to select districts, villages, herds and individual cattle. A total of 1,357 cattle from 310 herds were examined for BTB infection using a comparative intradermal tuberculin skin test (CIDT). Questionnaires were used to gather data on herd structure and herd management practices. A multilevel logistic mixed effect model was used to determine risk factors after accounting for clustering effect at three levels (village, herd and individual animal). Overall prevalence of BTB was 4.3% (95% CI = 3.4-5.6), with the highest prevalence recorded in Alamata district (5.6%) and lowest in Korem (1.6%). Multilevel logistic mixed effect model analysis identified exotic breed (OR = 3, p = 0.014), closed barn (OR = 2.6, p = 0.018), large herd size (OR = 2.6, p = 0.05) and purchase of cattle (OR = 2.1, p = 0.027) as important risk factors for BTB. Taken together, these findings suggest that the current dairy development program centred on the introduction of exotic and or crossed animals could have contributed to changing epidemiological situations of BTB in the study area.

The prevalence of brucellosis and bovine tuberculosis in ruminants in Sidi Kacem Province, Morocco

Bovine tuberculosis (BTB) and brucellosis are major endemic zoonoses in ruminants in Morocco that impact on both animal and human health. This study presents an assessment of the epidemiological and socioeconomic burden of bacterial zoonoses in Sidi Kacem Province in Northern Morocco from a cross-sectional survey of 125 cattle and/or small ruminant-owning households. In total, 1082 sheep and goats were examined from 81 households. The single intradermal comparative cervical test to screen for bovine tuberculosis was undertaken on 1194 cattle from 123 households and all cattle were blood sampled. Cattle and small ruminant sera were tested for brucellosis using the standard Rose Bengal Test (sRBT) and the modified Rose Bengal Test (mRBT). Bacteriology was performed on 21 milk samples obtained from cattle that were seropositive for brucellosis for isolation and phenotyping of circulating Brucella strains. Individual and herd prevalence for BTB in cattle of 20.4% (95% CI 18%-23%) and 57.7% (95% CI 48%-66%), respectively, were observed in this study. The prevalence of brucellosis in cattle at individual and herd level was 1.9% (95% CI 1.2%-2.8%) and 9% (95% CI 4.5%-1.5%), respectively. Brucella pathogens were isolated from three cattle milk samples and were identified as B. abortus using Bruceladder® multiplex PCR and B. abortus biovar 1 by classical phenotyping. All small ruminants were seronegative to sRBT, two were positive to mRBT. A higher risk of BTB and brucellosis was observed in cattle in intensive livestock systems, in imported and crossed breeds and in animals from larger herds (>15). The three risk factors were usually present in the same herds, leading to higher transmission risk and persistence of both zoonoses. These results highlight the importance of implementing control strategies for both BTB and brucellosis to reduce productivity losses and the risk of transmission to humans. Prioritising control for BTB and brucellosis in intensive livestock production systems is essential for human and animal health.

Prevalence of bovine and avian tuberculosis in camel herds and associated public health risk factors in Isiolo County, Kenya

A cross-sectional study was conducted among 308 lactating camels selected from 15 herds from three different camel milk clusters in Isiolo County, Kenya, to determine prevalence of bovine and avian tuberculosis using Single Comparative Intradermal Tuberculin Skin test. Seventy-five (75) questionnaires were administered to pastoralists/herders, and focus group discussions were conducted among 3-5 pastoralists/herders selected from each camel herd to collect information on camel husbandry and health management practices and knowledge on tuberculosis in livestock and wildlife. An overall prevalence of bovine and avian reactors was 3.57 and 18.18%, respectively, with bovine and avian reactors for different clusters being 2.38, 3.82, and 4.48% and 25, 17.2, and 11.94%, respectively. There was significant difference (p < 0.05) in prevalence of bovine and avian reactors between different clusters. There was a negative correction (r = -0.1399) between herd size and bovine reactors, while there was a positive correlation (r = 0.0445) between herd size and avian reactors. The respondents indicated that camel herds are exposed to several risk factors like close contact with other herds or livestock or wildlife during grazing and at watering points. Pastoralists have poor knowledge on mode of infection and transmission of bovine or avian tuberculosis. The high prevalence of bovine and avian reactors and pastoralists' poor knowledge on mode of transmission signify potential risk to public health.

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 characterization of bovine tuberculosis strains in two slaughterhouses in Morocco

BACKGROUND

Bovine tuberculosis (BTB) is caused by Mycobacterium bovis, which belongs to the Mycobacterium tuberculosis complex. Mycobacterium bovis have been described to be responsible of most cases of bovine tuberculosis. Although M. tuberculosis, M. africanum and non-complex mycobacteria were isolated from cattle. In Morocco, so far, no molecular studies were conducted to characterize the strains responsible of BTB. The present study aims to characterize M. bovis in Morocco. The present study was conducted in slaughterhouses in Rabat and El Jadida. Samples were collected from 327 slaughtered animals with visible lesions suggesting BTB.

RESULTS

A total of 225 isolates yielded cultures, 95% (n = 215) of them were acid-fast (AF). Sixty eight per cent of the AF positive samples were confirmed as tuberculous mycobacteria (n = 147), 99% of these (n = 146) having RD9 and among the latter, 98% (n = 143) positive while 2% (n = 3) negative for RD4 A total of 134 samples were analyzed by spoligotyping of which 14 were in cluster and with 41 different spoligotypes, ten of them were new patterns (23%). The most prevalent spoligotypes were SB0121, SB0265, and SB0120, and were already identified in many other countries, such as Algeria, Spain, Tunisia, the United States and Argentina.

CONCLUSION

The shared borders between Algeria and Morocco, in addition to the previous importation of cattle from Europe and the US could explain the similarities found in M. bovis spoligotypes. On the other hand, the desert of Morocco could be considered as an efficient barrier preventing the introduction of BTB to Morocco from West Central and East Africa. Our findings suggest a low level endemic transmission of BTB similar to other African countries. However, more research is needed for further knowledge about the transmission patterns of BTB in Morocco.

A review of risk factors for bovine tuberculosis infection in cattle in the UK and Ireland

Bovine tuberculosis (bTB) is an important disease of cattle caused by infection withMycobacterium bovis, a pathogen that may be extremely difficult to eradicate in the presence of a true wildlife reservoir. Our objective was to identify and review relevant literature and provide a succinct summary of current knowledge of risk factors for transmission of infection of cattle. Search strings were developed to identify publications from electronic databases to February 2015. Abstracts of 4255 papers identified were reviewed by three reviewers to determine whether the entire article was likely to contain relevant information. Risk factors could be broadly grouped as follows: animal (including nutrition and genetics), herd (including bTB and testing history), environment, wildlife and social factors. Many risk factors are inter-related and study designs often do not enable differentiation between cause and consequence of infection. Despite differences in study design and location, some risk factors are consistently identified, e.g. herd size, bTB history, presence of infected wildlife, whereas the evidence for others is less consistent and coherent, e.g. nutrition, local cattle movements. We have identified knowledge gaps where further research may result in an improved understanding of bTB transmission dynamics. The application of targeted, multifactorial disease control regimens that address a range of risk factors simultaneously is likely to be a key to effective, evidence-informed control strategies.

Risk factors associated with Mycobacterium bovis skin positivity in cattle and buffalo in Peshawar, Pakistan

A cross-sectional study was carried out to determine the prevalence of bovine tuberculosis (bTB) and associated risk factors in cattle and buffalo in Peshawar, Pakistan. Cattle and buffalo, randomly selected from all four towns of District Peshawar, were screened for bovine tuberculosis using comparative cervical intradermal tuberculin test (CCIT). For obtaining data on risk factors, sociodemographic condition, animal characteristics, and management, interviewer administered pretested questionnaire to animal owners. Multivariable logistic regression models were used to measure association between risk factors and comparative cervical intradermal tuberculin reactors. A total of 556 cattle and buffalo were screened for bovine tuberculosis. Out of 556 animals screened, 5.75 % (3.9-8.0 %) were found positive. The prevalence was higher in old animals (p = 0.001) as compared to younger animals. Prevalence also varied with source of animal (either raised on farm or purchased), stay of animals at night (indoor or outdoor), and herd size. Farmer's knowledge about transmission of TB from animals to human as well as signs and symptoms of TB was extremely low. Only 3.6 % farmers correctly stated the combination of three major symptoms of TB. Results of the study call for immediate intervention to control bTB in animals as well as its transmission to human population. Furthermore, it is suggested to emphasize on local epidemiology of bTB and husbandry practices of cattle and buffalo during the control program.

Development of an in vitro model of the early-stage bovine tuberculous granuloma using Mycobacterium bovis-BCG

Mycobacterium bovis causes 3.1% of human tuberculosis cases, as described by the World Health Organisation. In cattle, this organism causes bovine tuberculosis (BTB) which can have a prevalence of up to 39.5% in some developing countries. In developed countries, although the prevalence of BTB has been reduced through eradication programmes, complete eradication has in some cases proved elusive, with prevalences in cattle of 0.5% in the Republic of Ireland and of 4.3% in the UK. As the tuberculous granuloma is the fundamental lesion that reflects the pathogenesis, immune control and progression of BTB, we aimed to develop an in vitro model of the early-stage bovine tuberculous granuloma, in order to model the early stages of BTB, while also reducing the use of experimentally infected animals. In vitro models of human and ovine mycobacterial granulomas have previously been developed; however, so far, there is no model for the BTB granuloma. As the disease in cattle differs in a number of ways from that in other species, we consider this to be a significant gap in the tools available to study the pathogenesis of BTB. By combining bovine monocyte-derived macrophages infected with M. bovis-BCG and autologous lymphocytes we have developed an early-stage tuberculous bovine granuloma model. In the model, 3D cell aggregations formed a spherical-shape that grew for up to 11 days post-infection. This bovine tuberculous granuloma model can aid in the study of such lesion development, and in comparative studies of pathogenesis, such as, for example, the question of mycobacterial latency in bovine tuberculosis.

Mycobacterium tuberculosis causing tuberculous lymphadenitis in Maputo, Mozambique

Background

The zoonosis bovine tuberculosis (TB) is known to be responsible for a considerable proportion of extrapulmonary TB. In Mozambique, bovine TB is a recognised problem in cattle, but little has been done to evaluate how Mycobacterium bovis has contributed to human TB. We here explore the public health risk for bovine TB in Maputo, by characterizing the isolates from tuberculous lymphadenitis (TBLN) cases, a common manifestation of bovine TB in humans, in the Pathology Service of Maputo Central Hospital, in Mozambique, during one year.

Results

Among 110 patients suspected of having TBLN, 49 had a positive culture result. Of those, 48 (98 %) were positive for Mycobacterium tuberculosis complex and one for nontuberculous mycobacteria. Of the 45 isolates analysed by spoligotyping and Mycobacterial Interspersed Repetitive Unit – Variable Number Tandem Repeat (MIRU-VNTR), all were M. tuberculosis. No M. bovis was found.

Cervical TBLN, corresponding to 39 (86.7 %) cases, was the main cause of TBLN and 66.7 % of those where from HIV positive patients.

We found that TBLN in Maputo was caused by a variety of M. tuberculosis strains. The most prevalent lineage was the EAI (n = 19; 43.2 %). Particular common spoligotypes were SIT 48 (EAI1_SOM sublineage), SIT 42 (LAM 9), SIT 1 (Beijing) and SIT53 (T1), similar to findings among pulmonary cases.

Conclusions

M. tuberculosis was the main etiological agent of TBLN in Maputo. M. tuberculosis genotypes were similar to the ones causing pulmonary TB, suggesting that in Maputo, cases of TBLN arise from the same source as pulmonary TB, rather than from an external zoonotic source. Further research is needed on other forms of extrapulmonary TB and in rural areas where there is high prevalence of bovine TB in cattle, to evaluate the risk of transmission of M. bovis from cattle to humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-015-0603-5) contains supplementary material, which is available to authorized users.

Molecular Identification of Mycobacterium Species of Public Health Importance in Cattle in Zimbabwe by 16S rRNA Gene Sequencing

Mycobacterium species are naturally found in the environment as well as in domestic animals such as cattle. So far, more than 150 species of Mycobacterium, some of which are pathogenic, have been identified. Laboratory isolation, detection and identification of Mycobacterium species are therefore critical if human and animal infections are to be controlled. The objective of this study was to identify Mycobacterium species isolated in cattle in Zimbabwe using 16S ribosomal RNA gene amplification and sequencing. A total of 134 cow dung samples were collected throughout Zimbabwe and mycobacteria were isolated by culture. Only 49 culture isolates that were found to be acid-fast bacilli positive by Ziehl-Neelsen staining. The 16S rRNA gene was successfully amplified by PCR in 41 (84%) of the samples. There was no amplification in 8 (16%) of the samples. Out of the 41 samples that showed amplification, 26 (63%) had strong PCR bands and were selected for DNA sequencing. Analysis of the DNA sequences showed that 7 (27%) belonged to Mycobacterium neoaurum, 6 (23%) belonged to Mycobacterium fortuitum, 3 (12%) to Mycobacterium goodii, 2 (1%) to Mycobacterium arupense, 2 (1%) to Mycobacterium peregrinum or M. septicum and 1 isolate (0.04%) to Mycobacterium elephantis. There were 5 (19%) isolates that were non-mycobacteria and identified as Gordonia terrae, a close relative of Mycobacterium. The study therefore provided a molecular basis for detection and identification of Mycobacterium species in animals and humans.

Longevity of Mycobacterium bovis in Raw and Traditional Souring Milk as a Function of Storage Temperature and Dose

BACKGROUND

Unpasteurised fresh and souring dairy products form an essential component of household diets throughout many rural communities in southern Africa. The presence of milk-borne zoonotic pathogens such as Mycobacterium bovis (M. bovis), the causative agent of bovine tuberculosis and zoonotic tuberculosis in humans, constitute a public health threat, especially in remote areas with poor disease surveillance in livestock and highly compromised human health due to HIV/AIDS.

METHODS

In this study we used culture to determine the longevity of M. bovis in experimentally inoculated fresh and naturally souring milk obtained from communal cattle in the KwaZulu-Natal province of South Africa. The effect of bacterial load and storage temperature on the survival of M. bovis was evaluated by spiking mixtures of fresh milk and starter soured milk (aMasi) culture with three concentrations of bacteria (10(2), 10(4), 10(7) colony forming units/ml), followed by incubation under controlled laboratory conditions that mimicked ambient indoor (20°C) and outdoor (33°C) temperatures and periodic sampling and testing over time (0-56 days).

RESULTS

M. bovis cultured from samples of the fresh and souring milk was identified by PCR analysis. At the highest spiking concentration (10(7) cfu/ml), M. bovis survived for at least 2 weeks at 20°C; but, at all concentrations in the 33°C treatment, M. bovis was absent by three days after inoculation. Logistic regression analysis was used to assess the effects of bacterial concentration and time since inoculation, as well as determine the potential half-life of M. bovis in raw souring milk. Given the most favourable tested conditions for bacterial survival (20°C), approximately 25% of mycobacteria were alive after one day of storage (95% CI: 9-53%), giving an estimated half-life of M. bovis in raw souring milk of approximately 12 hours (95% CI: 7-27 hours).

CONCLUSIONS

This study demonstrates that M. bovis may survive in fresh and souring milk for periods of time that represent a risk of exposure to people consuming these products, as well as domestic or wild animal populations that have reported opportunities to consume homemade unpasteurised dairy products. The temperature at which the milk is soured and stored substantially affects the survival time of M. bovis.