Is there a ‘query’ over Q fever in your herd?

Q fever, caused by the bacterium Coxiella burnetti, is endemic in GB dairy farms1 with studies showing positive bulk milk samples ranging from 70% PCR positive in south-west England2 to 80% ELIZA positive results across 255 UK herds3.

Recently Q fever has become reportable in the UK and climate change is changing the future risk profile as the disease has the potential to have a significant impact on livestock health and production, however the disease is frequently overlooked as other infertility causes are often investigated first, which can lead to economic losses for farmers.

To help capture farmers’ experiences of Q fever, Ceva Animal Health has launched a national Q fever survey to assess the scale and on-farm awareness of the condition and the important role of vaccination in helping to prevent the disease.  The grassroots survey, which is approximately three minutes, long, can be carried out by visiting www.smartsurvey.co.uk/s/Y5EWLO/.  A prize draw will be carried out after the survey closes with 10 lucky participants winning a Q fever snood.

Renzo Di Florio, veterinary advisor at Ceva Animal Health, comments: “Despite Q fever being endemic in GB dairy herds, we believe that awareness amongst the farming industry is low.  Our National Q Fever Survey will help us ascertain how we can support farmers and vets when it comes to diagnostic challenges, treatment options and prevention through vaccination to help protect farmers, farming families and the related professions from the disease and reduce the impact of Q fever on farms.”

Jonathan Statham MA VetMB DCHP FRCVS, a RCVS registered specialist in cattle health, co-author of the ‘Dairy Herd Health’ textbook and chief executive of RAFT Solutions, adds: “Multiple surveys in the UK support Q fever prevalence ranging from 60 to 80% in our national dairy herd, including recent work carried out by RAFT Solutions in NE England and SW England (2021)4.  Reproductive issues are of course multifactorial and it is important therefore not to associate a Q fever positive diagnostic result as a single cause of infertility. However, increased level of metritis and endometritis, abortion and pregnancy loss or extended calving-conception intervals merit further investigation with Q fever as part of a herd health discussion that should of course address other infectious disease such as BVD, IBR or leptospirosis. Q fever is of further significance as a zoonosis and also as a potentially emerging disease in the context of climate change and changing vector patterns.”

Coxiella burnetii is zoonotic and can infect humans, cattle, goats, sheep and many other mammals, as well as reptiles, ticks and birds; the disease was originally known as ‘query fever’ until its true cause was first identified in Australia in 1935 after an outbreak of disease in abattoir workers.

The disease has the potential to cost farmers over £7,000 a year in a 100-cow dairy herd5 and infection is generally through inhalation of the bacterium, which can be spread through a number of ways, including ingestion, via blood from tick bites, birth fluids and foetal materials.  Q fever is usually described as mainly asymptomatic, as in humans.  When clinical signs occur, Q fever primarily affects reproductive performance in cattle and presents a serious threat to productivity.  Clinical signs in cattle include abortion, infertility (poor conception or increased calving interval), metritis (inflammation of the uterus), retained placenta, stillbirth and weak new borns.  Indeed, a cow that has been exposed to the bacteria is 2.5 times more likely to have an abortion6, 1.5 times more likely to have retained foetal membranes7 and 2.5 times more likely to have a high incidence of metritis/clinical endometritis8.  Infection may cause an increased calving to conception interval as well as increased early pregnancy loss.  Clinical signs in goats and sheep also include abortion.8

Presenting a health threat to farmers, farming families and related professions such as vets, veterinary technicians and abattoir workers, the bacterium is particularly resilient and can survive for extended periods of time in the environment.  For example, up to five months in soil9 and up to two years at minus 20oC10. It is also resistant to many commonly used disinfectants11.  Alongside environmental persistence, Coxiella burnetii can be spread on the wind12,13, 14.  An outbreak seen in the Netherlands (2007 – 2010) was linked to a 75-fold increase in goat numbers seen in the preceding 25 years15. The bacterium thrives in dry environments and rain has a negative impact on the distribution16.

For further information on Q fever please contact your local vet or visit www.qfever.co.uk.

References

  1. Velasova M. et al. 2017. Herd-level prevalence of selected endemic infectious diseases of dairy cows in Great Britain. J. Dairy Sci. 100:9215–9233
  2. Valergakis G. et al. 2012. Coxiella burnetii in bulk tank milk of dairy cattle in south-west England. Vet Record 11;171(6):156, 1-2
  3. Velasova M. et al. 2017. Herd-level prevalence of selected endemic infectious diseases of dairy cows in Great Britain. J. Dairy Sci. 100:9215–9233
  4. RAFT Solutions, data on file
  5. Ceva Animal Health, data on file
  6. Ordronneau, S., 2012. Impact de la vaccination et de l'antibiothérapie sur l'incidence des troubles de la reproduction et sur la fertilité dans des troupeaux bovins laitiers infectés par Coxiella burnetii. INRA - ONIRIS, 1300 BioEpAR Biologie, Epidémiologie et Analyse du Risque. Centre de Recherche Angers-Nantes,Nantes, France
  7. Ordronneau, S., 2012. Impact de la vaccination et de l'antibiothérapie sur l'incidence des troubles de la reproduction et sur la fertilité dans des troupeaux bovins laitiers infectés par Coxiella burnetii. INRA - ONIRIS, 1300 BioEpAR Biologie, Epidémiologie et Analyse du Risque. Centre de Recherche Angers-Nantes,Nantes, France
  8. Dobos A. et al. 2020. Serological screening for Coxiella burnetii in the context of early pregnancy loss in dairy cows. Acta Veterinaria Hungarica 68.3 (2020): 305-309
  9. Welsh et al., 1959. Q fever studies. XXI. The recovery of Coxiella burnetii from the soil and surface water of premises harboring infected sheep. Am. J. Hyg. 70 : 14–20
  10. McCaul TF, Williams JC. Developmental cycle of Coxiella burnetii: structure and morphogenesis of vegetative and sporogenic differentiations. J Bacteriol. 1981 Sep;147(3):1063-76. doi: 10.1128/jb.147.3.1063-1076.1981. PMID: 7275931; PMCID: PMC216147
  11. Heinzen et al., 1999. Developmental biology of Coxiella burnetii
  12. Hawker JI. et al. 1998. A large outbreak of Q fever in the West Midlands: windborne spread into a metropolitan area? Commun Dis Public Health. 1998; 1:180–7
  13. Tissot-Dupont H, Amadei MA, Nezri M, Raoult D. Wind in November, Q fever in December. Emerg Infect Dis. 2004 Jul;10(7):1264-9. doi: 10.3201/eid1007.030724. PMID: 15324547; PMCID: PMC3323349
  14. Clark et al, 2018. Airborne geographical dispersal of Q fever from livestock holdings to human communities: a systematic review and critical appraisal of evidence
  15. Roest H. et al. 2011. The Q Fever epidemic in The Netherlands: history, onset, response and reflection Epidemiol. Infect. (2011), 139, 1–12
  16. Nusinovici S. et al. 2015. Q Fever infection in dairy cattle herds: increased risk with high wind speed and low precipitation. Epidemiology & Infection 143.15 (2015): 3316-3326
1st December 2022

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