Emergency response efforts are underway to tackle the outbreak of Foot and Mouth Disease (FMD) virus type A Africa, which recently isolated variants revealed serious challenges for vaccination strategies. This outbreak, which struck Egypt in 2022, has raised alarming concerns over the efficacy of both local and imported vaccines against the newly emerged A/Africa/G-IV variant.
Foot and Mouth Disease is notorious as one of the most contagious diseases affecting cloven-hoofed animals, leading not only to potential animal suffering but also substantial economic repercussions for farmers and livestock industries alike. The study conducted by researchers aims to address the inadequacies of existing vaccines, which were found to be ineffective against the new viral strain.
Past outbreaks of FMD, such as the significant incidents recorded since the 1960s, underline the necessity for continual vaccine updates to cope with the rapid genetic evolution of the virus. Previous strains have shown varying levels of virulence and pathogenicity; hence the recent emergence of the A/Africa/G-IV variant presented both threats and challenges.
Researchers at the Animal Health Research Institute and the Central Laboratory for Evaluation of Veterinary Biologics embarked on this urgent assessment, utilizing both laboratory-based testing and direct challenge tests on calves to gauge vaccine performance. Their findings, as documented, unveiled disappointing protective efficacy, with only 20% and 40% protection efficacy observed against the new strain from local and imported vaccine formulations, respectively.
The methodology involved vaccinating groups of calves with different FMD vaccine batches—the local trivalent oil-inactivated vaccine and the imported polyvalent equivalent—followed by exposure to the A/Africa/G-IV variant. The antibody response was evaluated through rigorous Virus Neutralization Tests (VNT), and the results indicated alarmingly low protective ability against the new field isolate.
"The current inactivated FMD vaccines, whether locally produced or imported and specially intended for the A Iran-05 lineage, have proven ineffective against the prevailing field isolate A/Africa/G-IV," stated the research team. This depicts the urgent need for improved vaccine formulations, as the study reveals the genetic mismatches between vaccine strains and circulating viral strains, which have been extensive and concerning.
Given the urgency of the outbreak, regulatory measures included the implementation of rapid isolation and identification protocols of the virus to contain its spread. Authorities emphasized proactive measures, including expedited vaccine reformulations—a process already underway as evident from the researchers’ proactive stance to modify vaccine formulations to include the isolated strain.
The modified vaccine is now actively utilized in vaccination campaigns, serving as a proactive measure to prevent and manage the outbreak more effectively. The swift actions taken not only reflect the commitment to safeguarding livestock health but also signify the importance of vaccine adaptability to meet new viral challenges.
Understanding the genetic variation of FMD virus strains and effectively matching vaccines to these strains will be pivotal. The present outbreak highlights this necessity, as demonstrated by the ability for serotypes to mutate and evoke vaccine escape, leading to epidemics potentially leading to drastic financial losses.
Overall, continuous monitoring of FMDV strains and enhancing vaccine efficacy remains pivotal. Experts agree on the need for close collaboration between health agencies, veterinary authorities, and research institutions to dynamically respond to such viral outbreaks and to protect livestock health.