Chlamydien beim Wildwiederkäuer - Erregerreservoir für domestizierte Wiederkäuer und Mensch?

• Forschungsstelle: BLV
• Projektnummer: 1.08.18
• Projekttitel Englisch: Chlamydiae in wild ruminants - reservoir for domestic ruminants and humans?

Schlüsselwörter (Englisch)

Chlamydia, domestic ruminants, epidemiology, human health, molecular diagnosis, reservoir, wild ruminants, zoonosis.

Kurzbeschreibung (Englisch)

Chlamydophila abortus is the most common infectious abortigenic agent in small ruminants in Switzerland. The first Swiss case of human abortion by a zoonotic infection of a pregnant woman with Chlamydophila abortus from a caprine abortion was reported in the canton Graubünden. In Graubünden, economic losses due to chlamydial abortion in small ruminants are significantly higher than in the other cantons. Large flocks, extensive animal husbandry and mixing of different sheep flocks during summer time in the mountains promote the spread of disease. However, the seroprevalence in the canton Valais with similar management systems is much lower indicating other unknown factors favouring chlamydial abortion in small ruminants in the canton Graubünden. As wild ruminants are grazing on the same pastures as domestic sheep and goats in the mountains, the question raises if they could play a role in infectious spread and transmission of chlamydioses. So far, the knowledge about chlamydiae in wild ruminants is scarce. Therefore, the aim of this project is to define the prevalence of Chlamydia in wild ruminants (deer, chamois, alpine ibex) in the canton Graubünden. The range of chlamydial species and in particular the detection of the same strains of Chlamydophila abortus in wild and domestic ruminants in the same region will elucidate the potential role of wild ruminants as a reservoir for domestic ruminants and the potential zoonotic risk for humans having contact to them (i.e. hunters, gamekeepers).

Projektziele (Englisch)

The main goals of this project are :
(i) to define the prevalence of Chlamydia in wild ruminants in the canton Graubünden
(ii) to define the role of Chlamydia in wild ruminants as a reservoir for domestic ruminants
(iii) to define the zoonotic potential of Chlamydia in wild ruminants

To achieve these mains goals, we plan to apply already available sensitive and specific molecular diagnostic tools such as conventional 16S rRNA PCR or Taqman real-time PCR methods. Furthermore, MicroArray technology is validated in our lab (IVPZ) to diagnose chlamydial infections in animals. Using these sensitive and specific methods will enable us to identify the correct chlamydial species which will be important to de-termine the relevance for domestic ruminants and human zoonotic infection.
The diagnosis of chlamydial infections will be completed by traditional methods such as smear preparation, cell culture, and immunohistochemistry. These diagnostic tools will be applied to clinical samples available from retrospective and prospective studies in wild ruminants from the canton Graubünden (n=750).

The population of wild ruminants in the canton Graubünden is composed of about 50'000 animals (Jahresbe-richt Jagd 2006, Amt für Jagd und Fischerei Graubünden). Around 9'400 wild ruminants (mainly deer, roe deer and chamois) are hunted per year. The sample size required for detecting chlamydiosis (95% confi-dence level) will be 149 and 59 samples at an expected prevalence of 2% and 5%, respectively. For estima-tion of 10% disease prevalence in a population of 50'000 animals to within 5% at the 95% confidence interval, we should test about 150 animals for each category : retrospective eye swabs, retrospective serum samples, prospective eye swabs, prospective serum samples, prospective organ samples (not available for the retros-pective part). Depending on the results in the first part of the study (retrospective), we would be still able to modify the amount of the prospective samples. The samples (n=750) will be composed as follows :
· Retrospectively (n=300) : 

• chamois : serum samples from 1999 (project infectious keratoconjunctivits, IKC) (n=150) 
• Alpine ibex and chamois : eye swabs (project IKC, extracted DNA) (n=150)

· Prospectively (n=450) :

• Deer, chamois, alpine ibex (Amt für Jagd und Fischerei, Kanton Graubünden, mainly during the hunting season and Schweizerischer Nationalpark Kanton Graubünden) : 
• organs samples (liver, lung, genital organs, intestine) : fresh frozen (-80°C) and for-malin-fixed, paraffin-embedded (n=150)
• serum samples (n=150)
• eye swabs (n=150)  

Umsetzung und Anwendungen (Deutsch)

31.05.2007: Umsetzung:

Empfehlungen an Nutztierhalter zum Weidemanagement
Erkenntnisse zu Sanierungsprogrammen
Grundlagen für Risikoabschätzung

Stärkung der Position zur Anerkennung als OIE-Referenzlabor (Selektionssitzung 2007/mvo)

Umsetzung und Anwendungen (Englisch)

This work will provide a first insight on the prevalence of Chlamydia in wild ruminants. The obtained results will :
(i) provide further insight into the epidemiology of chlamydial diseases, particularly chlamydial abortion in do-
mestic ruminants and its high prevalence in the canton Graubünden
(ii) indicate the need of proactive surveillance or even control strategies of chlamydiae in wild ruminants in
Switzerland and possibly Europe
(iii) predict strategies for new emerging pathogens such as Chlamydia-like organisms
(iv) reduce the risk to public health (zoonosis) due to chlamydial infections
(v) improve the diagnostic capabilities for chlamydioses in wildlife

Publikationen / Ergebnisse (Englisch)

Holzwarth, N.; Pospischil, A.; Marreros, N.; Ryser-Degiorgis, M.-P.; Mavrot, F.; Frey, J.; Thoma, R.; Borel, N. (2010) Alpine ibex (Capra i. ibex) is not a reservoir for chlamydial infections of domestic ruminants and humans. European Journal of Wildlife Research, accepted for publication.

Holzwarth, N.; Pospischil, A.; Ryser-Degiorgis, M.-P.; Marreros, N.; Frey, J.; Thoma, R.; Borel, N. (2010)
Chlamydial prevalence in Alpine ibex from Switzerland. 8th German Chlamydial Workshop, Herrsching, Germany, March 4th – 6th 2010.

Holzwarth, N.; Pospischil, A.; Hilbe, M.; Ryser-Degiorgis, M.-P.; Marreros, N.; Mavrot, F.; Frey, J.; Thoma, R.; Borel, N. (2009) Epidemiological investigations in wild ruminants in Switzerland. International Meeting of young veterinary pathologists, Pombia, Italy, July 2nd – 4th 2009.

Holzwarth, N.; Pospischil, A.; Ryser-Degiorgis, M.-P.; Marreros, N.; Frey, J.; Thoma, R.; Borel, N. (2009)
Chlamydiae in wild ruminants – reservoir for domestic ruminants and humans? 7th German Chlamydial Workshop, Lübeck, Germany, March 24th – 26th 2009.

Holzwarth, N. et al (2008) Chlamydiae in wild ruminants – reservoir for domestic ruminants and humans? International Meeting of young veterinary pathologists, Asti, Italy, June 26th-28th 2008.

Holzwarth, N. et al (2008) Chlamydiae in wild ruminants – reservoir for domestic ruminants and humans? COST 855 Working group Meeting on chlamydial serology, Hellenic Pasteur Institute, Athens, Greece, June 12th, 2008.)

 

Zugehörige Dokumente

• 1 08 18 Datenblatt MJB2011, Borel [PDF] 82 kB
• finalarticle.pdf [PDF] 257 kB