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Mycoplasma conjunctivae infection is self-maintained in the Swiss domestic sheep population
M Janovsky1, J Frey, J Nicolet
1Institute of Animal Pathology, University of Berne, Länggassstrasse 122, CH-3012 Berne, Switzerland.
Abstract:
Bacteriological and serological investigations were performed to assess whether the domestic sheep population is a reservoir of Mycoplasma conjunctivae in Switzerland. Among a sample of 69 sheep showing clinical signs of infectious keratoconjunctivitis (IKC) in three Swiss cantons, M. conjunctivae was identified 53 times (76.8%). A commercially prepared indirect ELISA was used to detect M. conjunctivae antibodies in 674 sera of adult sheep. We analysed a stratified random sample of 123 sheep herds from 25 out of the 26 Swiss cantons. At least one positive animal was detected in 89.4% of the herds. In positive herds (n=110), 57.1% of the individual animals tested positive. To assess the importance of sheep's age in the spread of M. conjunctivae, 209 sera of adult sheep and 93 lamb sera among eight sheep herds were analysed using the indirect ELISA. Seroprevalence in 2-6-month-old lambs was 50.5%, indicating that the IKC agent is spread in sheep flocks during raising. Lambs experimentally infected with M. conjunctivae carried the agent for 8 and 23 weeks, respectively, depending on the strain used for challenge. We conclude that the M. conjunctivae-infection is endemic and self-maintained in the domestic sheep population in Switzerland.
Insights
Domestic sheep in Switzerland are a significant reservoir for Mycoplasma conjunctivae, the cause of infectious keratoconjunctivitis (IKC). This bacterium is endemic and self-maintaining within sheep flocks, affecting both adult sheep and lambs.
Area of Science:
- Veterinary Microbiology
- Animal Health
- Ophthalmology
Background:
- Mycoplasma conjunctivae is a primary cause of infectious keratoconjunctivitis (IKC) in small ruminants.
- The role of domestic sheep as a reservoir for M. conjunctivae in Switzerland was previously unclear.
Purpose of the Study:
- To investigate the prevalence of Mycoplasma conjunctivae in Swiss domestic sheep.
- To determine if domestic sheep populations serve as a reservoir for M. conjunctivae.
- To assess the role of sheep age in the epidemiology of M. conjunctivae infections.
Main Methods:
- Bacteriological identification of M. conjunctivae from sheep with clinical signs of IKC.
- Indirect ELISA serological testing for M. conjunctivae antibodies in adult sheep sera and lamb sera.
- Analysis of sheep herds across multiple Swiss cantons.
Main Results:
- M. conjunctivae was identified in 76.8% of sampled sheep with clinical signs of IKC.
- Antibodies to M. conjunctivae were detected in 89.4% of analyzed sheep herds.
- Seroprevalence in lambs aged 2-6 months was 50.5%, indicating early flock transmission.
Conclusions:
- Domestic sheep in Switzerland are an endemic and self-maintaining reservoir for Mycoplasma conjunctivae.
- The study confirms M. conjunctivae spreads within sheep flocks during the raising period.
- Infectious keratoconjunctivitis agent is widespread in the Swiss sheep population.