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

Brucellosis in hospitalized patients and their animals in the agro-pastoral region of Theniet El Had (Algeria) during ten years (2013-2023)

Introduction

Brucellosis is an important zoonosis problem worldwide. It's also recognized as a clinical and health problem in Algeria.

Methods

This research is a descriptive study to determine the prevalence of brucellosis and some clinical and epidemiological aspects of hospitalized patients in the agro-pastoral region of Theniet El Had for ten years, between March 2013 and March 2023. During the study period, 180 patients (61.66% men and 38.33% women) with confirmed brucellosis based on clinical symptoms and serological tests were hospitalized for treatment. Patients working with animals were requested to screen their animals (383 goats from 27 suspicious farms with no history of vaccination), 16, 71% of goats from 44%, and 44% herds were infected.

Results

The occurrence of human cases varied from 49.18 to 66.02pcm (cases/100,000 inhabitants) with an average of 58, 48pcm (cases/100,000 inhabitants). Almost half of hospitalized people who had been in contact with animals could have been contaminated by direct contact. Consumption of unpasteurized dairy products during the last 2 months was at the order of 95.55%. A family history of Brucellosis was observed in 36 (20%) patients. Brucella epididymo-orchitis occurred in 18.01% while relapse occurred in a small proportion of 7.22%.

Conclusions

Local authorities should prevent human brucellosis with surveillance systems, disease declarations, biosecurity programs, and warning communities about the hazards of consumption of unpasteurized milk and dairy products.

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.