Erysipelas is one of those "old-time" diseases that has found renewed life. But this time it's showing up in the sow herd, not its more familiar place in the finishing herd.

"The rules of the disease have changed," says Kent Schwartz, Iowa State University pathologist. "There is more opportunity for erysip-elas to occur at ages we didn't think were an issue."

Some of the reasons for the impact on the sow herd include: misuse of vaccines, lack of naturally acquired infection and changing biology of the erysipelas organism, says Schwartz.

Swine practitioner, Max Rodibaugh, Frankfort, Ind., has seen sows break with the disease just before or just after farrowing. "If we administer vaccines before breeding, protection may not last 120 to 130 days until the sows farrow." He says the timing and type of vaccines may need to be adjusted.

In sows, erysipelas produces the typical diamond-shaped skin lesions, poor appetite and lactation failure. Rodibaugh doesn't know why the disease has surfaced in sows. "When we see sows with skin lesions, signs frequently follow in the pig population in the chronic form," he notes.

According to some estimates, 30 percent to 50 percent of healthy pigs may be harboring the erysipelas organism in their tonsils or lymph tissues.

Veterinarian Tim Loula, St. Peter, Minn., says it may simply have been an overlooked disease in sows. He points to signs in the sow herd that could be missed, such as chronic lameness, a sow going off feed – especially at farrowing, a downer sow or an occasional sudden death. "Individual treatments of penicillin or tylosin make it difficult to culture and diagnose erysipelas," he notes. Loula also believes that some of the industry's high sow mortality rate could be tied to erysipelas.

"It's important to have protection just before farrowing, and we want to pass on immunity to the piglets," says Loula.

Spotting a few sows with lesions in a herd of 3,000 is an indication of variable immunity, says Schwartz. Low prevalence (less than 1 percent) and low severity, particularly in large herds, tends to suggest vaccination has been beneficial, but that protection is spotty. Grow/finish pigs also can benefit from reviewing your vaccination program.

"Since most herds are at risk, sound immunity is good insurance," says Schwartz.