Keep guard up for strep, parasuis in newly weaned pigs

October 31, 2019
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Newly weaned pigs face many challenges — new environment, feed, pen mates. They also face the challenge of bacterial infections like Streptococcus suis (strep) and Haemophilus parasuis (parasuis), the two most common systemic bacterial diseases found in weaned pigs.

Strep and parasuis can both flare up when immune systems are stressed, according to Daniel Gascho, DVM, Four Star Veterinary Service.

“Where do strep and parasuis come from?” Gascho asked. “They are always here. A lot of research has been done that shows almost 100% of pigs have strep by the time they are weaned.”

Expect the same for parasuis, he warned.  Swab samples taken from the floors and walls of most nurseries will be positive for parasuis without the pigs showing a sign of the disease.

Strep, parasuis symptoms

The most common symptom of strep is swollen joints in nursery pigs.

“It’s that pig with the fat hock, a little lame, doesn’t want to get up,” Gascho said. “We call it dog sitting, where their back end is down and propped up on their front legs.

“Also pretty common and what most people think of with strep is the neurological form — a pig that’s paddling, eyes twitching, maybe going in circles, head pressing. You’ve all seen this.”

Nursery pigs sick with parasuis look depressed, gaunt and are slow growing. A necropsy of a pig infected with parasuis will have lots of fibrin, a protein associated with blood clotting.

“Just like strep, parasuis can get into joints and…can cross the blood-brain barrier and cause some meningitis and swelling of the brain,” Gascho explained. “This is why it is very important to diagnose these diseases. The treatment or prevention may be completely different.”

One other caution: Just because strep was diagnosed in the nursery a year ago doesn’t mean the symptoms you’re seeing are strep related.   Producers will “come out money ahead in the long run” if they get an accurate diagnosis and use the right treatment protocol for the pathogen at hand.

Ounce of prevention

While many nursery pigs carry these bacterial diseases, they don’t all get sick. Gascho recommended “an ounce of prevention…to prevent their immune system from getting depressed, because any stressor will trigger these diseases.”

For example, nurseries that are too cold, too hot, poorly ventilated or overcrowded could compromise a pig’s immune system enough to activate a disease outbreak.

“There are always some stressors that we can’t avoid,” he added. “Weaning alone is a huge one. They just went from milk to pellets or ground feed. The best thing you can do is to do everything perfectly that you have control over.”

If flare-ups occur, try to prevent it from happening in the next group. Use all-in/all-out management and thoroughly clean between groups.

Management options

In some cases, autogenous vaccines can be very useful, especially for strep, Gascho said. The key to making vaccines work is diagnosing the type of strep.

“A few years ago, I did research on strep and at that time, there were at least 134 serotypes of Strep suis alone,” he said. “It’s very critical you diagnose the strep because if it is the same strep every time, then it’s a great candidate for a vaccine.”

In very severe cases of strep, infected sows can be treated with an antibiotic for strep right before farrowing to decrease shedding. “If you have a really bad strep, this might be an option,” Gascho said. “If you can cut nursery mortality by 3%, you easily cover the cost of treating all sows in the herd.”

Pigs showing neurological symptoms must be treated with an antibiotic as soon as possible.  “Time is of the essence,” he said, adding that using a corticosteroid was “very critical in these cases to help reduce swelling of the brain. It won’t treat strep but will buy you some time to allow an antibiotic to work.”

He suggested using an appropriately labelled antibiotic for treatment of strep and follow directions.

Watch for dehydration

“Another big thing to consider is if the pigs can’t walk, they can’t drink and they will die of dehydration,” Gascho said. “Even if they can walk, but are unstable and getting beat around, they don’t stand a chance in the main pen with pigs.”

He recommended putting these sick pigs either in a hospital pen or in a small pen in an aisle with a little water while being treated. After a few days, they should be strong enough to join the other pigs.

“The big picture is there’s always a treatment to try” for strep and other bacterial diseases, Gascho added.

“Don’t give up. Find [the affected pigs] as soon as possible and know when your individual treatments are not keeping up. It doesn’t take very many dead pigs to justify the cost of treating the whole room…And no treatment in the world will make up for preventing them from getting sick in the first place,” he concluded.