Little-known sapovirus causes diarrhea in baby pigs

A couple of puzzling cases of diarrhea in baby pigs that didn’t test positive for the usual culprits were recently identified through genome sequencing as a porcine sapovirus, reported Daniel Hendrickson, DVM, Four Star Veterinary Service in Farmland, Indiana.

The diarrhea started in baby pigs at 6 to 7 days of age with symptoms similar to coccidiosis, but testing was negative. That’s when Hendrickson had the samples tested by polymerase chain reaction, and the sapovirus was discovered.

“I hadn’t heard much about sapovirus,” he admitted. “It is now another virus veterinarians and producers need to check when they are trying to reduce scours in the farrowing house.”

Sapovirus symptoms

Since porcine sapovirus was discovered in US swine herds 40 years ago, little attention has been paid to the virus. But improved testing methods now commonly detect sapovirus as a co-infection in diarrhea outbreaks and the sole cause in a few other outbreaks.

Hendrickson first learned of the virus when working with a couple of farms to clear up scours in the farrowing barn.

“They thought scours was pretty much under control, but they kept seeing a scour at 6 to 7 days of age,” Hendrickson explained. “It would last a few days and was a pasty scour like coccidia, not watery like Escherichia coli, rotavirus and some other viral baby pig scours. We would only find some rotavirus in the first few days after birth, but then testing would go negative.

“It’s not high mortality, but pigs go backwards pretty hard for 2 to 3 days,” he added. “The pigs at weaning will recover but will be 1 to 2 pounds smaller because of those couple of days of scours.”

He also was working with another client that had battled diarrhea for a couple of years and decided to check for sapovirus. Tests came back positive for the virus and showed very high loads of it.

Care and treatment

During a sapovirus outbreak, Hendrickson suggested keeping the pigs dry and well hydrated. Also make sure the sow is milking well. Most outbreaks last 3 to 4 days but can reoccur.

“We’d have a few weeks where it was pretty bad, and then it would get better for a month,” Hendrickson said. “Then it would creep back, and I knew the immunity was waning.”

Initially, he tried a feedback program but had little success. Then he moved to vaccinating the sows at 4 weeks and 1 week pre-farrowing, which provided consistent immunity.

“I think sapovirus is endemic in the sows and their environment,” Hendrickson said. “Cleaning and disinfection are critical to lower the virus level in the environment.”

More information

In 2015, the Swine Health Information Center produced an information sheet on sapovirus, available online at Porcine Sapovirus.

More information is also available at: Porcine sapoviruses: Pathogenesis, epidemiology, genetic diversity, and diagnosis.





Cold stress poses threat to calf health even at mild temps

Cold stress can become a drag on growth rates if calves aren’t kept warm and dry even at temperatures as high as 60° F.

“For every 2 degrees below the critical temperature, which is 60° F for calves up to 21 days old, they need 1% more energy just to stay warm,” reported Trey Gellert, DVM, Four Star Veterinary Service. For calves over 21 days, the critical temperature is 42° F.

“I think many producers don’t realize calves can be experiencing cold stress over half the year and probably two-thirds of the year in Ohio and Wisconsin,” he said.

Other factors such as wind chill, drafts, moisture and humidity increase cold stress, and calves will expend even more energy to stay warm.

Gellert offered some strategies to reduce stress on calves.

Increase energy for winter

“The biggest issue I see is not changing the milk-replacer feedings for winter and keeping them the same as summer,” Gellert said. “The amount of energy given to calves from the summer to the winter should increase.”

He recommended increasing the amount of milk replacer and extra feedings during winter.

“We know those calves are experiencing cold stress, and they have to use energy to stay warm,” he added. “The biggest opportunity for feeders is to keep those calves warm with more feed.”

Prior to winter, Gellert suggested gradually increasing feed to help calves improve body condition and build a natural layer of insulation to help them handle cold temperatures.

Maintain good bedding

Calves need clean, dry bedding to stay warm and healthy. Gellert prefers straw bedding over sand or sawdust because calves can huddle into it and keep warm.

“Having good-quality bedding during the winter is an economic benefit because the animal is able to properly regulate body temperature,” he said.

“Generally, the health of the animal will improve if it is not using energy just to stay warm,” he added. “Average daily gain and feed-to-gain ratio will improve.  And the more bedding used, the better it is.”

Wet bedding that’s either muddy or contaminated by scours or other disease should be changed to prevent cold stress and illness.

“If they don’t have good bedding and are sitting in mud, that’s a double whammy,” Gellert said. “It pulls all the heat out of those calves.”

Wind, rain protection

The worst conditions for calves are outside in rain and wind. Cold stress quickly sets in, and the energy requirements to stay warm increase.

Gellert suggested using some type of wind break to help the animals stay out of the wind, as well as a shelter to stay dry. The best option is a barn to house the animals.

Calf jackets for newborns and, in some cases, calves up 16 weeks of age can also help them stay warm and dry. Jackets may also be needed for calves housed inside during the winter.

“When it’s 0° F outside, calves are still experiencing cold stress even when in a barn,” he said. “Those low critical temperatures really [adversely] affect them.”

Producers need to pay attention to cold stress in their young animals and take steps to help them stay warm.

“The health of the animal will improve if they are not using energy to stay warm. They will use energy to stay healthy and grow,” he said.