Rabies in southeast Brazil: a change in the epidemiological pattern

Area of Science:

• Veterinary Epidemiology
• Virology
• Molecular Biology

Background:

• Rabies remains a significant public health concern globally.
• Understanding rabies virus evolution and transmission dynamics is crucial for control strategies.
• Previous studies in Brazil have highlighted the presence of diverse rabies virus lineages.

Purpose of the Study:

• To investigate changes in the epidemiological profile of rabies virus in southeastern Brazil from 1993 to 2007.
• To characterize rabies virus isolates antigenically and genetically.
• To identify distinct endemic cycles of rabies virus in different animal species.

Main Methods:

• Epidemiological analysis of rabies virus isolates from various animal species.
• Antigenic characterization using a panel of eight monoclonal antibodies.
• Genetic characterization through nucleoprotein gene sequencing.

Main Results:

• A shift in the epidemiological profile of rabies virus was observed between 1993-1997 and 1998-2007.
• Antigenic variant 2 (dog-associated) was prevalent in domestic animals from 1993-1997.
• Antigenic variant 3 (bat-associated) was detected in cattle, and four distinct variants were identified in bats and urban pets from 1998-2007.
• Nucleotide similarity analysis revealed two main groups: dog and bat antigenic variants, indicating separate endemic cycles.

Conclusions:

• The study demonstrates a significant alteration in the rabies virus epidemiological profile in southeastern Brazil over a 15-year period.
• Distinct endemic cycles of rabies virus are maintained in different animal populations, particularly between domestic animals and bats.
• These findings underscore the importance of ongoing molecular surveillance for effective rabies control programs.