Facing the Human and Animal Brucellosis Conundrums: The Forgotten Lessons

Abstract

Brucellosis is a major zoonotic disease caused by Brucella species. Historically, the disease received over fifty names until it was recognized as a single entity, illustrating its protean manifestations and intricacies, traits that generated conundrums that have remained or re-emerged since they were first described. Here, we examine confusions concerning the clinical picture, serological diagnosis, and incidence of human brucellosis. We also discuss knowledge gaps and prevalent confusions about animal brucellosis, including brucellosis control strategies, the so-called confirmatory tests, and assumptions about the primary-binding assays and DNA detection methods. We describe how doubtfully characterized vaccines have failed to control brucellosis and emphasize how the requisites of controlled safety and protection experiments are generally overlooked. Finally, we briefly discuss the experience demonstrating that S19 remains the best cattle vaccine, while RB51 fails to validate its claimed properties (protection, differentiating infected and vaccinated animals (DIVA), and safety), offering a strong argument against its current widespread use. These conundrums show that knowledge dealing with brucellosis is lost, and previous experience is overlooked or misinterpreted, as illustrated in a significant number of misguided meta-analyses. In a global context of intensifying livestock breeding, such recurrent oversights threaten to increase the impact of brucellosis.

The Development of Diagnostic and Vaccine Strategies for Early Detection and Control of Human Brucellosis, Particularly in Endemic Areas

“…The isolation of the Brucella species is a challenging task for many researchers, and many have attempted to overcome these challenges by using techniques that directly detect them in tissues or blood. However, none of these technologies has proven more reliable and effective than the isolation of bacteria itself [ 79 ]. In spite of the lack of ideal diagnostic sensitivity, Brucella cultivation is more likely to occur when known techniques are employed [ 76 ].…”

“…Its strong agglutinating activity makes IgM most effective in areas nearby hospitals. It is still possible for SAT to produce false-negative findings, even under these conditions, if the incubation period of the disease is prolonged [ 79 ]. Due to the predominance of non-agglutinating antibodies in long-evolution cases, the diagnostic performance of SAT is poor in areas with restricted access to medical facilities.…”

Detection of Brucella abortus Vaccine Strain RB51 in Water Buffalo (Bubalus bubalis) Milk

“…Brucellosis is one of the most important zoonoses affecting livestock and humans worldwide [ 1 , 2 ]. Brucella abortus RB51 is a rough mutant strain derived from the virulent strain B. abortus 2308 after several passages on trypticase soy agar with rifampin [ 3 , 4 ].…”

First record of the human infection of Brucella melitensis in Kyrgyzstan: evidence from whole-genome sequencing-based analysis

“…The number of human brucellosis cases worldwide exceeds 500,000 annually but the true incidence in some endemic countries can be expected to be higher due to unspecific clinical symptoms of the disease [ 11 , 12 ]. Human brucellosis is a direct result of animal brucellosis and most cases are reported from countries of the Mediterranean Basin, the Middle East, Asia, Africa, and South America with hundreds or thousands of new cases every year [ 2 , 8 , 13 – 15 ].…”