In February 2022, an outbreak of Japanese encephalitis in Australia drew the attention of pork producers, veterinarians, animal and public health government officials, and allied industries around the world. In the US, the pork industry began monitoring Australia’s situation and response, ramping up preparedness activities immediately. Some of these efforts were shared during a recent symposium hosted by the Center for the Ecology of Infectious Disease at the University of Georgia, sponsored in part by the Swine Health Information Center.
Of those attending virtually or in person, 30 were with USDA-affiliated agencies and Dr. Michael Neafsey, One Health Coordinator for USDA APHIS, was an invited speaker. He said the likelihood of JEV being found in the US is low, however, taken seriously by his agency. If established, substantial human and animal health issues along with significant economic impacts are expected outcomes. As with West Nile virus, eradication would be difficult if not impossible if JEV becomes established. Dr. Neafsey said the most likely mechanism for JEV introduction and establishment of infection would be through infected mosquitoes and expressed concern about delayed recognition of infection in livestock due to the disease’s non-specific presentation.
Dr. Neafsey outlined USDA APHIS Veterinary Services feral swine sample collection programs and pre-existing relationships with local resources as key to JEV surveillance efforts. Veterinary Services staff also have pre-established communications chains.
If suspected, JEV diagnosis will come from virus isolation and molecular tools, according to Dr. Neafsey. This process will include sequencing for detection and differentiation of flaviviruses. The National Animal Health Laboratory Network along with the National Veterinary Services Laboratories in Ames, Iowa, and Plum Island, New York, will be instrumental in detection of JEV, should there be an incursion.
Existing USDA response frameworks include FAD preparedness which Dr. Neafsey said have been used to successfully detect, control, and contain diseases for many years. FAD response plans provide disease specific information and response strategies. Dr. Neafsey said USDA’s JEV disease response strategy is under review and has been removed from the agency’s website as it was outdated.
In conclusion, Dr. Neafsey outlined USDA response goals which are to detect control and contain FAD outbreaks as quickly as possible, eradicate the FAD using strategies that stabilize animal agriculture, the food supply, the economy, and protect public health and the environment. Goals also include providing science and risk-based approaches and systems to facilitate continuity of business for noninfected animals and noncontaminated animal products.
Examining JEV Introduction Risk in the US
Dr. Natalia Cernicchiaro, Kansas State University, presented information on the risk of introduction of JEV in the continental US. She noted that the US shares similar climate and environmental conditions with countries where JEV is epidemic, that the US has competent vectors and hosts, and that there has been increased travel and trade to and from JEV-affected regions. These characteristics, along with the lack of active JEV surveillance in the US, make this region at risk to a JEV incursion.
This risk assessment addressed: