Epidemiological Study of Mycobacterium bovis Infection in Buffalo and Cattle in Amazonas, Brazil

Condemnation of bovine carcasses due to tuberculosis-gross lesions in Rio Grande do Sul, Brazil: Associated risk factors

Surveillance of bovine tuberculosis (bTB) lesions in animals at slaughterhouses is useful for controlling and eradicating the disease, besides providing epidemiological information. This study aimed to identify risk factors for bovine tuberculosis (bTB) condemnation in cattle at slaughterhouses in Rio Grande do Sul, Brazil. A logistic regression analysis was conducted using data on bTB-related condemnations. Variables examined included animal origin, number of slaughtered animals, season, inspection level (state or municipality), animal sex, and slaughterhouse location. A total of 297,817 Animal Transport Guides were evaluated, representing the transportation of 3497,521 animals. Among these, 6097 (2.05%) had at least one animal condemned due to bTB lesions. Risk factors for condemnation included larger batch sizes, female animals, slaughterhouses, and animal origin. The higher condemnation frequency in females and regions with dairy farms suggests links to milk production. Variation in condemnation rates by inspection level and slaughterhouse highlights the need for standardized procedures in identifying bTB lesions. Identifying these risk factors enables targeted interventions to enhance disease control and eradication efforts.

Occurrence of tuberculosis among people exposed to cattle in Bangladesh

BACKGROUND

Tuberculosis (TB) has been an important public health concern in Bangladesh. The most common cause of human TB is Mycobacterium tuberculosis, while bovine TB is caused by Mycobacterium bovis.

OBJECTIVE

The objective of this study was to determine the frequency of TB in individuals with occupational exposure to cattle and to detect Mycobacterium bovis among cattle in slaughterhouses in Bangladesh.

METHODS

Between August and September 2015, an observational study was conducted in two government chest disease hospitals, one cattle market, and two slaughterhouses. Sputum samples were collected from individuals who met the criteria for suspected TB and had been exposed to cattle. Tissue samples were collected from cattle that had low body condition score(s). Both humans and cattle samples were screened for acid-fast bacilli (AFB) by Ziehl-Neelsen (Z-N) staining and cultured for Mycobacterium tuberculosis complex (MTC). Region of difference (RD) 9-based polymerase chain reaction (PCR) was also performed to identify Mycobacterium spp. We also conducted Spoligotyping to identify the specific strain of Mycobacterium spp.

RESULTS

Sputum was collected from a total of 412 humans. The median age of human participants was 35 (IQR: 25-50) years. Twenty-five (6%) human sputum specimens were positive for AFB, and 44 (11%) were positive for MTC by subsequent culture. All (N = 44) culture-positive isolates were confirmed as Mycobacterium tuberculosis by RD9 PCR. Besides, 10% of cattle workers were infected with Mycobacterium tuberculosis in the cattle market. Of all TB (caused by Mycobacterium tuberculosis) infected individuals, 6.8% of individuals were resistant to one or two anti-TB drugs. The majority of the sampled cattle (67%) were indigenous breeds. No Mycobacterium bovis was detected in cattle.

CONCLUSIONS

We did not detect any TB cases caused by Mycobacterium bovis in humans during the study. However, we detected TB cases caused by Mycobacterium tuberculosis in all humans, including cattle market workers.

Coordinated response of milk bacterial and metabolic profiles to subacute ruminal acidosis in lactating dairy cows

BACKGROUND

Bovine milk is an important source of nutrition for human consumption, and its quality is closely associated with the microbiota and metabolites in it. But there is limited knowledge about the milk microbiome and metabolome in cows with subacute ruminal acidosis.

METHODS

Eight ruminally cannulated Holstein cows in mid lactation were selected for a 3-week experiment. The cows were randomly allocated into 2 groups, fed either a conventional diet (CON; 40% concentrate; dry matter basis) or a high-concentrate diet (HC; 60% concentrate; dry matter basis).

RESULTS

The results showed that there was a decreased milk fat percentage in the HC group compared to the CON group. The amplicon sequencing results indicated that the alpha diversity indices were not affected by the HC feeding. At the phylum level, the milk bacteria were dominated by Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes both in the CON and HC groups. At the genus level, the HC cows displayed an improved proportion of Labrys (P = 0.015) compared with the CON cows. Results of both the principal components analysis and partial least squares of discriminant analysis of milk metabolome revealed that samples of the CON and HC groups clustered separately. A total of 31 differential metabolites were identified between the two groups. Of these, the levels of 11 metabolites decreased (α-linolenic acid, prostaglandin E2, L-lactic acid, L-malic acid, 3-hydroxysebacic acid, succinyladenosine, guanosine, pyridoxal, L-glutamic acid, hippuric acid, and trigonelline), whereas the levels of the other 20 metabolites increased in the HC group with respect to the CON group (P < 0.05).

CONCLUSION

These results suggested that subacute ruminal acidosis less impacted the diversity and composition of milk microbiota, but altered the milk metabolic profiles, which led to the decline of the milk quality.

Milk Contamination by Mycobacterium tuberculosis Complex, Implications for Public Health in Amazonas, Brazil

ABSTRACT

In Brazil, contamination of raw milk with Mycobacterium tuberculosis complex (MTC) has been reported in several states. The highest rate of consumption of raw milk and its derivatives in Brazil occurs in Amazonas. This state also has the highest prevalence of tuberculosis in both humans and livestock. We assessed the contamination of cow's milk and buffalo's milk with MTC in Amazonas, focusing on Mycobacterium bovis, the species most commonly found in cattle and buffalo. In 2019, 250 samples of raw milk (91 from cattle, 159 from buffalo) were collected before processing from three milk plants in the state of Amazonas. The samples were placed into 21 pools and analyzed using shotgun metagenomic sequencing and taxonomic classification with Kraken 2 and MegaBLAST. To confirm the identity of mycobacterial species found, BLASTN was used to identify specific genomic positions in the TbD1 and RD1 regions and flanking RD4 region. MTC genetic material was identified in all pools of raw milk. Genetic material consistent with M. bovis was identified in seven pools of raw milk (1 from cattle, 6 from buffalo). Buffalo's milk had significantly higher MTC reads than did cow's milk. The common practice of consumption of raw milk and its derivatives in Amazonas presents a risk to public health. Urgent measures to prevent transmission of foodborne tuberculosis are needed in the Amazon region. Greater efforts and resources also should be directed toward elimination of bovine tuberculosis in cattle and buffalo herds in Amazonas and the rest of Brazil.

HIGHLIGHTS

Prevalence, Risk Factors, and Diagnostic Efficacy of Bovine Tuberculosis in Slaughtered Animals at the Chiang Mai Municipal Abattoir, Thailand

This study aimed to (1) investigate the prevalence of bovine tuberculosis (bTB) in slaughtered animals at the Chiang Mai Municipal abattoir in Chiang Mai, Thailand; (2) identify animal-level risk factors for bTB at the abattoir; and (3) evaluate the performance of techniques for bTB detection at the abattoir. From April 2020 to March 2021, 161 animals registered for slaughter were randomly selected for the study. Animal data including age, sex, species, body condition scores, and origins of the animals were collected. Meat inspection was performed by a trained meat inspector. Tissue samples of the lung, liver, and lymph nodes were collected for histopathological diagnosis and polymerase chain reaction (PCR) detection of Mycobacteria and specifically Mycobacterium bovis. The prevalence of bTB during meat inspection and PCR was calculated separately. Animal-level factors affecting bTB were determined using multivariate logistic regression analysis. The performance of meat inspection and PCR was evaluated using a Bayesian approach. The prevalence of bTB was 12.4% (20/161) and 34.8% (56/161) when the disease was diagnosed using meat inspection and PCR, respectively. Buffaloes had a significantly higher risk of being identified as bTB-positive using PCR compared to beef cattle (odds ratio = 2.19; confidence interval = 1.11–4.30). The median of posterior estimates of sensitivity (Se) and specificity (Sp) to detect bTB using meat inspection were 20.8% [95% posterior probability interval (PPI) = 9.1–36.5%] and 87.8% (95% PPI = 79.6–95.4%), respectively. The medians of the posterior estimates of Se and Sp for PCR were 88.6% (95% PPI = 70.5–98.3%) and 94.4% (95% PPI = 84.7–98.8%), respectively. These findings demonstrate that bTB is highly prevalent among slaughtered animals. PCR can be used as an ancillary test for bTB surveillance at abattoirs in Thailand.

Spatiotemporal distribution and temporal trends of brucellosis and tuberculosis in water buffalo (Bubalus bubalis) in Brazil

The buffalo herds in Brazil have been an alternative for increasing the economy in different biomes. For this reason, knowledge of the spatial distribution of diseases of mandatory notification in buffalo herds, such as brucellosis and tuberculosis, is essential to guarantee the quality of exported animal products, as well as assist in strategies of national control and eradication programs. In the present study, we aimed to evaluate the spatiotemporal distribution and temporal trends of brucellosis and tuberculosis in buffalo in Brazilian states between 2012-2019. During this period, 474 cases of brucellosis and 604 cases of tuberculosis were observed in buffalo in Brazil, with no significant differences between the total number of cases and incidence risk. The spatial distribution for the states was mostly heterogeneous, showing similarities of occurrences for both diseases in the south, north, and the states of Minas Gerais and Pernambuco. In the eight years evaluated, tuberculosis showed cyclical variation every 1-2 years; however, for brucellosis, there was a cyclical trend only between 2012-2015, with a significant decrease until 2018. Among Brazilian states, Pará had greater disease case numbers, with 34 % for brucellosis and 40.6 % for tuberculosis. Temporal trend analysis showed an increase for Pernambuco (annual percentage change [APC]: 21.0 [CI = 20.3; 21.8]), Paraná (APC: 27.1 [CI = 5.6; 53.0]), and Santa Catarina (APC: 10.4 [CI = 0.8; 21.0]) for brucellosis, and for tuberculosis, only for Santa Catarina state (APC: 24.1 [CI = 15.5; 33.3]). Spatiotemporally, there were four high-risk brucellosis clusters with a primary cluster, cluster A (relative risk [RRs] = 53.42, P < 0.001), involving the state of Amazonas between 2014-2015. For tuberculosis, there were three states of high risk, with a primary cluster, cluster E (RRs = 28.18, P < 0.001), involving the states of Pará, Roraima, Amazonas, Rondônia, and Acre in 2014. In conclusion, brucellosis and tuberculosis in buffalo in Brazil are heterogeneously distributed, with well-defined regions of high historical risk of infection. Among these regions, the states of Amazonas, Pará, Amapá, and Minas Gerais stand out due to the higher risk of infection for both brucellosis and tuberculosis, alerting Brazilian authorities to the need for disease control actions.

Genetic Diversity and Potential Paths of Transmission of Mycobacterium bovis in the Amazon: The Discovery of M. bovis Lineage Lb1 Circulating in South America

Bovine tuberculosis (bTB) has yet to be eradicated in Brazil. Herds of cattle and buffalo are important sources of revenue to people living in the banks of the Amazon River basin. A better understanding of Mycobacterium bovis (M. bovis) populational structure and transmission dynamics affecting these animals can significantly contribute in efforts to improve their sanitary status. Herein, we sequenced the whole genome of 22 M. bovis isolates (15 from buffalo and 7 from cattle) from 10 municipalities in the region of the Lower Amazon River Basin in Brazil and performed phylogenomic analysis and Single Nucleotide Polymorphism (SNP)-based transmission inference to evaluate population structure and transmission networks. Additionally, we compared these genomes to others obtained in unrelated studies in the Marajó Island (n = 15) and worldwide (n = 128) to understand strain diversity in the Amazon and to infer M. bovis lineages. Our results show a higher genomic diversity of M. bovis genomes obtained in the Lower Amazon River region when compared to the Marajó Island, while no significant difference was observed between M. bovis genomes obtained from cattle and buffalo (p ≥ 0.05). This high genetic diversity is reflected by the weak phylogenetic clustering of M. bovis from the Lower Amazon River region based on geographic proximity and in the detection of only two putative transmission clusters in the region. One of these clusters is the first description of inter-species transmission between cattle and buffalo in the Amazon, bringing implications to the bTB control program. Surprisingly, two M. bovis lineages were detected in our dataset, namely Lb1 and Lb3, constituting the first description of Lb1 in South America. Most of the strains of this study (13/22) and all 15 strains of the Marajó Island carried no clonal complex marker, suggesting that the recent lineage classification better describe the diversity of M. bovis in the Amazon.