Erysipelothrix infections
Christian gortazar1 and dolores gavier-
WIDEN2
1IREC National Wildlife Research Institute (CSIC-UCLM- JCCM), Ciudad Real, Spain
2National Veterinary Institute (SVA), Uppsala, Sweden The genus Erysipelothrix contains the species E.
tonsillarum (9 serotypes), considered to be non- pathogenic, and E. rhusiopathiae (19 serotypes), a primary or facultative bacillus pathogen of a wide taxonomic range of hosts. Bacteria of this genus are non-sporulating Gram-positive bacilli of the family Erysipelotrichaceae. Important serovars for humans and swine include 1a, 1b and 2(70).The geographical distribution of E. rhusiopathiae infections in European wildlife is unknown, but the bacterium has a common and worldwide distribution in domestic pigs. It is also an important cause of disease outbreaks in fowl, in particular turkeys, and of polyarthritis in sheep. Erysipelothrix rhusiopathiae infection has been reported in a wide range of mammals, birds, reptiles, amphibians, fish and invertebrate species. The agent is often isolated from the tonsils of apparently healthy Eurasian wild boar. Clinical disease and sporadic mortality have been recorded in Eurasian wild boar, Iberian ibex ( Caprapyrenaica), moose in Canada (Alces alces), and many free-living and captive wild bird species(71). In wild birds, E. rhusiopathiae infection occurs mostly sporadically, but it may occasionally cause outbreaks of mortality1-71).
Erysipelothrix rhusiopathiae is ubiquitous and able to persist for a long period of time in the environment, including marine environments. Transmission occurs by direct and indirect contact with living infected hosts, or with dead animals or contaminated soil. The infection may be acquired orally or through skin lesions.
I nfection by E.
rhusiopathiae in pigs may cause acute septicaemic infections, mostly fatal, particularly in epidemics. Acute disease is accompanied by disseminated intravascular coagulation, microthrombi, small haemorrhages (petechiae and ecchymoses) and enlarged spleen. With a longer disease course, multifocal purulent tonsillitis, necrosis of the skin (cutaneous infarcts), fibrinous polyarthritis and endocarditis develop. Lesions may develop in other organs, such as lungs, kidneys and brain. Chronic forms may progress into vegetative valvular endocarditis or chronic arthritis. Septic thrombi can detach from the heart valves, and cause septic embolization in various organs.Erysipelothrix rhusiopathiae infection in birds results in septicaemia with haemorrhages and petechiae in serosae and muscles.
Clinical signs in wild boar include facial oedema, fever and reduced activity. Affected wild boar are often found in or close to waterholes. No specific clinical signs are observed in wild birds.
Erysipelothrix rhusiopathiae isolation on standard culture media is straightforward, this being the most appropriate diagnostic tool. Serological screening tests include enzyme- linked immunosorbent assay (ELISA). PCR techniques are available(72).
Control in domestic animals requires good standards of sanitary hygiene and immunization procedures. Common disinfectants are effective in killing E. rhusiopathiae, and penicillin is the drug of choice for antibiotic therapy. Most commercial vaccines for pigs or turkeys are bacterins or attenuated live strains of E. rhusiopathiae. Antibiotic treatments and vaccination have been used in wildlife translocations(73).
The infection is readily transmitted to humans by direct contact with infected hosts such as carrier animals, as occurs through occupational exposure in the animal husbandry and meat- processing industries. In humans, this infection is often subclinical, but it can occasionally cause arthritis and severe endocarditis.
I nfection by E. rhusiopathiae causes severe economic losses to the pig and poultry industry.