Exudative epidermitis (EE) or “Greasy Pig” is one of the most common skin diseases encountered by suckling and weaned pigs. Clinical problems are not unusual for gilt start up herds where the passive colostrum derived maternal immunity provided from the gilts to their offspring can be very low. The primary bacterial cause of the disease is virulent strains of Staphylococcus hyicus and Staphylococcus chromogenes. The six toxins that can be produced by these bacteria include ExhA, ExhB, ExhC, ExhD, SHETA and SHETB. The lesions of EE can be limited to localized infections or can be generalised over the entire body. Increased sebaceous exudation can quickly develop into epidermal erosions and crusts. Pigs with generalized EE become dehydrated, lose weight and are affected by increased mortality.
Recently a massive outbreak of exudative epidermitis (EE) occurred on a Western German piglet producing farm with 350 productive sows. Gilts are produced on site in this herd. In one group of piglets, more than 50% of suckling and nursery piglets were clinically affected.(100% affected is a possibility if this disease gets completely out of control) Both gilts and sows in this herd showed evidence of localized EE lesions usually in the area of the neck. With sows being affected it would make you wonder if a new strain entered the herd. Generalized infection in suckling and nursery piglets resulted in mortality rates of up to 10% per weaning group. Both Staphylococcus (St.) hyicus and St. chromogenes strains were detected in affected skin lesions, with St. hyicus also present in systemic localizations. St hyicus and chromogenes can be isolated from healthy skin so positives from a skin swab need to be interpreted with some caution. These organisms should not be found in internal tissues. In this case the St. hyicus strains had both ExhA and SHETA toxins. These isolates had resistance to penicillin. Initially, antibiotic treatment with trimethoprim-sulfadiazine on a preventive basis, further antibiotic treatment of affected pigs as well as washing with an antiseptic solution improved the clinical signs. This was a lot of work, expensive and not sustainable given that antimicrobial usage was well above target for the nursery.
In order to reduce the antibiotic use, an autogenous vaccine against the isolated St. hyicus and St. chromogenes strains for gilts and sows was produced and applied as a basic immunization twice before farrowing. In addition, external and internal biosecurity was evaluated and adjusted using an objective questionnaire (Bio-check.UGentTM). The combination of measures resulted in a long-term improvement of the overall health status. Several months after the severe EE outbreak, the sporadic occurrence of new EE cases in individual piglets could be controlled by the adjustment of the autogenous vaccine with an additional St. hyicus isolate that was incorporated into subsequent batches of vaccine. The authors of the case report commented that this case demonstrated that a disease control plan needed to address the multifactorial nature of the disease. In this case continuous monitoring of isolates revealed a new strain that was subsequently added to the autogenous vaccine.
These types of cases are reported from time to time in the literature especially when an initial explosive outbreak is followed by increased antimicrobial use for prevention and treatment. Ongoing nursery mortality of 7% (in the absence of PRRS and PCV2 health issues) indicate how severe some cases can become. Maes et al (2018) reported a very similar outbreak in Belgium. In that case they were able to use an autogenous vaccine prefarrowing in some batches and left other batches unvaccinated as a control. The nurseries in the batches where sows were double vaccinated with an autogenous vaccine had a significant reduction in mortality as well as the antibiotic usage being cut in half. No one has really followed the decay of the maternally derived antibodies (MDA) when sows are vaccinated prefarrowing with an EE autogenous vaccine. It is expected that the antibodies will have declined to a low level within a few weeks post weaning but this is probably enough time for weaned pigs to build some active protection while still under the umbrella of partial protection from mom.
References: Lutz Brimmers , Juhle Buch , Jürgen Harlizius , Annette Kuczka , Michael Kleinmans , Andrea Ladinig , Heinrich Kreutzmann Increased piglet losses upon exudative epidermitis – a case report Tierarztl Prax Ausg G Grosstiere Nutztiere
. 2023 Aug;51(4):248-256. doi: 10.1055/a-2088-6163. Epub 2023 Aug 8.
Ioannis Arsenakis, Filip Boyen, Freddy Haesebrouck, and Dominiek G D Maes Autogenous vaccination reduces antimicrobial usage and mortality rates in a herd facing severe exudative epidermitis outbreaks in weaned pigs Vet Rec. 2018 Jun 30; 182(26): 744.
Published online 2018 Mar 29. doi: 10.1136/vr.104720
