Impact of herd mobility on brucellosis seroprevalence and spread risk resulting from cross-border transhumance

BACKGROUND

Cross-border livestock mobility through transhumance is mainly practiced in West African countries for seasonal access to resources and market. Cross-border herds are involved in the dynamic of transboundary animal diseases among them brucellosis taken as model. Brucellosis is a zoonotic disease causing abortion.

OBJECTIVES

This study explores the seroprevalence of brucellosis according to mobility and infection spread between Mali and Côte d'Ivoire in the context of seasonal cross-border transhumance.

METHODS

From February to April 2021, a transversal serological survey of brucellosis was conducted on 521 cattle from 111 transhumant herds and 283 cattle from 59 sedentary herds, all from Mali.

RESULTS

The global individual seroprevalence for Brucella spp. in transhumant and sedentary cattle from Mali was 8.2% (95% CI = 6.0-10.5). At herd level, seroprevalence was 21.2% with a significant variation between transhumant (11.7%) and sedentary (39.0%) herds. For herds in transhumance, cattle seropositivity was associated with a previous infection suspected by herdsmen odds ratio (OR = 4.4; 95% CI = 1.1-18.1) and unknown abortion aetiology (OR = 4.3; 95% CI = 1.0-17.3). The departure region (coming from Sikasso) and previous brucellosis infection or unexplained abortion could be used to predict Brucella infection in transhumant herds with a probability of around 60%. The risk of brucellosis introduction in host regions was high despite the individual animal seroprevalence of 3.6% and a low sale rate in transhumant cattle.

CONCLUSIONS

The findings suggest that testing transhumant during border control and survey of cattle markets and sales could improve risk control of the spread of disease at regional scale.

[Comparison of the performance of viral load screening from plasma and from the oneblotting paper (Oudried Blood Spot), protocol in people living with the human immunodeficiency virus (PLHIV) in Bamako]

INTRODUCTION

The use of blotting paper as a support for quantification of viral load could improve the virological monitoring of patients on Human Immunodeficiency Virus treatment in Mali. The urgency is obvious to us that the coverage in charge is only 10% for the achievement of the 3rd 90.

OBJECTIVE

To assess the performance of viral load screening (sensitivity, specificity, concordance) of DBS from the one spot DBS protocol according to plasma in people living with the human immunodeficiency virus (PLHIV) in Bamako.

METHODS

A total of 130 blotting papers were made from blood samples received from five sites for monitoring live persons with HIV. These blotting papers thus made were analyzed with the Abbott m2000 apparatus for the purpose of quantifying the viral load with plasma as reference sample. The extraction was done with the m2000SP automatic extractor, following the protocol 1.0 mL HIV-RNA DBS Protocol for paper. Furthermore, the extraction of plasma RNA on the m2000SP was done according to the 0.6 mL HIV-1 RNA protocol.

RESULTS

With 130 samples with detectable viral loads, we obtained a correlation of r = 0.837 (p <0.001). In addition, the average difference between the viral load on blotting paper and plasma was 0.512 log / virological copies with a kappa coefficient = 0.708. The threshold of 1000 copies / mL defined as virological success in our study allowed us to obtain a sensitivity of 87% and a specificity of 100%.

CONCLUSION

Decentralized zones or virological plasma monitoring is not accessible, the new Protocol one spot of Abbott laboratory offers an interesting opportunity for the follow-up of these patients with good performance at the threshold of 1000 copies. The use of DBS as a virological support can contribute effectively to the achievement of the 3rd 90.

[What's new in HIV/AIDS: Some selected topics]

News related to HIV/AIDS was marked in 2012 both by emerging therapies, as well as by the changes management strategies. Therefore, we will discuss the crucial issue of when to start antiretroviral therapy, which appears to be more and more early. Furthermore, after the U.S. validation of the pre-exposure prophylaxis for individuals at high risk of HIV acquisition, prevention of HIV transmission has returned to the spotlight. Finally, we will review some promising novel molecules whose mechanisms of action, half-life or low dosage open the door to new treatment strategies.