Human Seroreactivity to Secreted Molecules of Corynebacterium pseudotuberculosis

Corynebacterium pseudotuberculosis is an infectious agent that occurs in small ruminants causing caseous lymphadenitis, and more rarely in humans causing lymphadenitis and pneumonia. The breeding small ruminants have great economic importance in Brazil. Rural farm workers and veterinary students who acquired this disease suffered from weakening symptoms for weeks, and the identification of the etiological agent was time-consuming and complex. Due to the low prevalence of case records, there is probably no available commercial diagnostic kit for C. pseudotuberculosis infection in humans. This study aimed to describe human seroreactivity to secreted antigens from C. pseudotuberculosis. Reactivity of serum from farm workers (n = 14), individuals who work with the bacillus at laboratory (n = 8) or individuals without contact (n = 25) was tested with secreted proteins from PAT10 strain of C. pseudotuberculosis by Western blotting. Samples of all (100%) farm workers showed reactivity to 31 kDa, 71 kDa and 164 kDa proteins, while laboratory workers showed 87.5%, 62.5 % and 37.5%, and no-contact 20%, 0% and 16%, respectively. All sera recognized the 275 kDa protein. Our data suggest that C. pseudotuberculosis secreted proteins are antigenic in humans and the recognition profiles allowed the identification of individuals with and without prior contact with this bacillus. This is the first paper which describes human reactivity to C. pseudotuberculosis in serum samples of workers in Brazil.

Etiological Agent, Pathogenesis, Diagnosis, Treatment, Measures for Prevention and Control of Caseous Lymphadenitis Disease in the Small Ruminants with Special Reference to Sheep

Caseous lymphadenitis (CL) is a chronic infectious disease caused by Corynebacterium pseudotuberculosis (C. pseudotuberculosis) that is transmitted mainly by contact with contaminated exudate wounds. Caseous lymphadenitis affects different species of animals and is considered an occupational zoonotic disease. CL is responsible for important economic losses in the small ruminant industry, which include decreased production, damaged quality of milk and wool, reproductive disorders, total or partial confiscation of carcasses, and depreciation of the skin. Caseous lymphadenitis disease can present in two clinical pictures: a skin or superficial picture and a visceral or deep picture. The presumptive diagnosis of CL in the skin is based on the exploration of superficial lymph nodes. These have little value in diagnosing visceral CL, where the main sign is emaciation. The prevention and control of CL involve identifying the skin condition and debriding the abscesses. In addition to the treatment of superficial lesions, the animal facilities must be repaired and adapted. To avoid exposure of negative herds to CL, new animals must be subjected to observation to identify any of the clinical manifestations. Another form of control is vaccination, though only some countries have commercial vaccines. General information on the etiological agent and its characteristics can be used to improve the understanding of this disease.