Erysipelas Outbreak in Sows on a 1000 Sow Farrow-to-Finish Farm

An outbreak of acute Erysipelas was diagnosed in sows housed in a single gestation barn on a commercial 1000 sow farrow-to-finish farm. This case report highlights Erysipelas as a continuing threat to intensively reared swine housed in entirely environmentally-controlled housing.

A swine herdsman observed classic red diamond shaped lesions on the skin of four sows in the same gestation barn. The sows were lame and lethargic. He immediately called his veterinarian.

A review of records revealed that all four sick animals had either recently shared a gestation pen or were serviced by a common boar and that the sows were 10 to 18 months of age. Clinical examination revealed polygonal dark red to purple, sometimes raised lesions on the skin of the dorsum and hams. All animals were reluctant to walk and favored one or more limbs when walking. Rectal temperatures ranged from 103.5-106.5F. Careful examination of other animals in the herd revealed no other affected animals. Because, in addition to Erysipelas, diamond skin lesions have also been reported with septicemia caused by Actinobacillussuis, blood for culture was collected from each sow directly into blood culture bottles containing tripticase-soy broth (Bacto Blood Culture Bottles, Difco).Erysipelothrixrhusiopathiae was isolated from the blood in two of the four sows. Therapeutic doses   of   penicillin    were   administered intramuscularly for three consecutive days to the four sick animals, all pen-mates of the sick animals and all boars that had recent contact with the sick animals. The herdsman was instructed to watch other animals closely for evidence of acute or chronic Erysipelas. Also, it was recommended that the four sick animals should be sold to market after appropriate antibiotic withdrawal times because of the potential for the development of chronic arthritic Erysipelas.  All four sick animals responded to antibiotic therapy. No other animals developed acute Erysipelas and there has been no recurrence in the nine months since the outbreak.

A review of the vaccination program for females in this herd revealed no obvious omissions. When gilts entered the herd at five to six months of age, they were vaccinated with a combination vaccine   or   Erysipelas,    parvovirus   and Leptospirosis. When they were successfully mated, usually within one to five weeks, they received a booster vaccination. At weaning, all sows that would remain in the breeding herd received a booster   vaccination   for   Erysipelas   and Leptospirosis. Boars were not vaccinated. It was recommended that all boars be vaccinated twice annually for Erysipelas and Leptospirosis. Also, methods used for vaccination were reviewed to ensure that all animals were vaccinated correctly, records were kept of vaccinations, vaccines were stored correctly and needles and syringes were cleaned and disinfected between uses.

The cause of this outbreak was not clear. There was no previous history of Erysipelas in this herd. It is possible that one of the unvaccinated boars was shedding E.rhusiopathiae and that some of the exposed females were susceptible due to missed vaccinations, poor vaccination technique or poor response to vaccination. The source of E. rhusiopathiae in outbreaks of Erysipelas was previously thought to be persistence in the soil;

however, more recent research has shown that it can remain viable in soil for only 35 days under optimal conditions. We now know that many healthy swine, some estimate 30-50%, are tonsillarcarriers of E. rhusiopathiae. The organism can be shed in oronasal secretions, urine and feces. Rodents and birds can also serve as reservoirs. Spread of infection in a swine herd is by close contact or by contaminated water, feed or bedding.

The classic lesions of diamond-skin infarcts are highly suggestive of Erysipelas; however, several facts need to be considered in making a diagnosis of Erysipelas. Actinobacillussuis can also cause an acute and fatal septicemia with cutaneous infarcts. Also, in all outbreaks of Erysipelas, diamond skin lesions may not be a prominent feature. Sometimes animals are just found dead with no cutaneous lesions. Typical post-mortem lesions in acute Erysipelas, in addition to cutaneous infarcts, include slightly to moderately enlarged, "meaty" spleens, mild pulmonary edema and renal cortical petechiae. In chronic Erysipelas, polyarthritis with periarticiular fibrosis and vegetative valvularendocarditis are the most common lesions. Bacterial culture is required for confirmation. From dead animals, lymph nodes, liver and spleen are excellent tissues to culture. If you are doing your own bacteriology, remember E. rhusiopathiae grows very slowly on blood agar and colonies and/or typical green discoloration of agar due to alpha-hemolysis may not be visible until 24-36 hours of incubation. Do not throw away your culture plates too early!

This report serves as a reminder that modem herds are still at risk for Erysipelas and clinical disease may only be a "stress" or a missed vaccination away. Good vaccination programs done according to label recommendations should prevent Erysipelas. However, if an outbreak does occur, aggressive targeted parenteral antibiotic therapy is usually effective.

-DougScholz, Class of 1996

-Greg Stevenson, DVM.PhD

-Sandra Amass, DVM, MS