Very recently, porcine reproductive and respiratory syndrome (PRRS) was reported in Uruguay and Senecavirus A (SVA) was diagnosed in Columbia. Through an international network of veterinarians, academics and allied industry, the Swine Health Information Center (SHIC) surveys for swine diseases circulating in other countries.
The occurrence of PRRS in Uruguay was reported to the World Organization for Animal Health on July 20, 2017. A subclinical infection of PRRS was diagnosed through indirect ELISA testing and RT-PCR and five premises affected.
Officials report an epidemiological investigation has started on those premises and on pig farms where breeding pigs were imported in the last 10 years. Sampling in slaughterhouses will also continue.*
Daniel Correia-Lima-Linhares, DVM, assistant professor in the Department of Veterinary Diagnostic and Production Animal Medicine at Iowa State University, has been on the ground in Uruguay and closely monitoring the outbreak. In 2000, he said Uruguay’s Ministry of Agriculture and the swine industry completed a serological study of pigs there, looking for antibodies of PRRS, pseudorabies virus (PRV), classical swine fever (CSF), and other diseases.
They did not find antibodies, confirming the country was negative for these diseases. A follow-up study with 614 serum samples from pigs across Uruguay was conducted from 2014 to 2016. The samples were tested for those same diseases and resulted in evidence of subclinical PRRS, confirmed this month.
“The message is you cannot rely on clinical signs of some foreign animal disease in animals,” Linhares said. “There are variants of those viruses that might cause infections that aren’t obvious but still there. Look at Uruguay. PRRS was only discovered because they looked for it and did the testing.”
Uruguay officials are investigating where the PRRS virus came from by using sequencing to characterize the genome.
“Internally in Uruguay, production systems and genetic companies are testing their flows to determine if they are positive or negative,” he said. “They are starting to discuss whether to pursue elimination or not. Even though it is PRRS, it appears non-virulent, perhaps vaccine-like. Since they are not seeing clinical signs, they could argue it’s not a clinically important event at this time.”
Uruguay borders Brazil and Argentina, and both of those nations are not accepting pigs from Uruguay at this time. The objective is to try to protect the health status of pigs in those countries.
Senecavirus A in Columbia
SVA was diagnosed in Brazil in 2015 and 2016. The newly affected Colombian herd had vesicles on the snout and coronary bands – it tested negative for foot-and-mouth disease (FMD), but positive for SVA. In a report issued following whole-genome phylogenetic analysis, it was indicated the Colombian strain clusters most closely with the contemporary strain from the U.S.**
Douglas Marthaler, DVM, associate professor in the Kansas State University College of Veterinary Medicine and Veterinary Diagnostic Laboratory, has been involved in testing samples from Colombia as the effort to determine its source continues.
“The swine industry in Colombia is just as concerned about disease outbreak and spread as the U.S. industry,” Marthaler said. “In this case, the client wanted an answer since the pigs were negative for FMD. This led to work with collaborators to figure out the cause of clinical disease.”
While SVA is present around the world, much is unknown about its transmission and persistence.
“As the virus is discovered in other countries, we need to understand transmission and the genetic relationship between the global strains,” Marthaler added. “The genetic sequence is important to understand and determine if or when strains emerge in any country, including the U.S.”
The affected farm in Colombia had relatively strict biosecurity protocols, was PRRS negative, and was located five kilometers from the nearest pig farm; they were not expecting a disease break from any virus.
As a result of the discovery of SVA in Colombia, due diligence by the industry, practitioners and farmers is underway, as all wish to maintain and protect the health of animals.
“Never underestimate the ability of these pathogens to keep throwing us for a loop,” Marthaler said. “Understanding disease emergence and genetic relationship on the global level helps us protect U.S. swine herds.”
Identification of the virus is the first step, in his opinion, followed by sequencing to help understand viral variation and spread.
Linhares shares the same urgency.
“The earlier we detect foreign animal disease, the better our chances to manage or eliminate it,” he said.
His encouragement is for effective surveillance systems: “We must detect as early as we can, respond as early as we can and be cost effective.”
SHIC has funded researchers at the University of Minnesota to develop a more formal and regular way to monitor for emerging and circulating swine diseases around the world.
Editor’s Note: *Source: https://live-ccms.pantheonsite.io/sites/default/files/en_imm_0000024372_20170721_152635.pdf
**Source: Sun D, Vannucci F, Knutson TP, Corzo C, Marthaler DG. Emergence and whole-genome sequence of Senecavirus A in Colombia. Transbound Emerg Dis. 2017;00:1–4. https://doi.org/10.1111/tbed.12669