Editing Q fever (section)

=== Epidemiology ===
With the exception of New Zealand, which is currently free of Q fever, the disease is present throughout the world. Numerous epidemiological surveys have been carried out. They have shown that about one in three cattle farms and one in four sheep or goat farms are infected,<ref>{{cite journal | vauthors = Guatteo R, Seegers H, Taurel AF, Joly A, Beaudeau F | title = Prevalence of Coxiella burnetii infection in domestic ruminants: a critical review | journal = Veterinary Microbiology | volume = 149 | issue = 1–2 | pages = 1–16 | date = April 2011 | pmid = 21115308 | doi = 10.1016/j.vetmic.2010.10.007 }}</ref> but wide variations are seen between studies and countries. In China, Iran, Great Britain, Germany, Hungary, the Netherlands, Spain, the US, Belgium, Denmark, Croatia, Slovakia, the Czech Republic, Serbia, Slovenia, and Jordan, for example, more than 50% of cattle herds were infected with Q fever.<ref>{{cite journal | vauthors = Pexara A, Solomakos N, Govaris A | title = Q fever and seroprevalence of Coxiella burnetii in domestic ruminants | journal = Veterinaria Italiana | volume = 54 | issue = 4 | pages = 265–279 | date = December 2018 | pmid = 30681125 | doi = 10.12834/VetIt.1113.6046.3 }}</ref><ref>{{Cite journal | vauthors = Pexara A, Solomakos N, Govaris A |date=2018-01-01 |title=Q fever and prevalence of Coxiella burnetii in milk |journal=Trends in Food Science & Technology |language=en |volume=71 |pages=65–72 |doi=10.1016/j.tifs.2017.11.004 |issn=0924-2244}}</ref><ref>{{cite journal | vauthors = Dobos A, Gábor G, Wehmann E, Dénes B, Póth-Szebenyi B, Kovács ÁB, Gyuranecz M | title = Serological screening for Coxiella burnetii in the context of early pregnancy loss in dairy cows | journal = Acta Veterinaria Hungarica | volume = 68 | issue = 3 | pages = 305–309 | date = September 2020 | pmid = 33156002 | doi = 10.1556/004.2020.00035 | s2cid = 226269478 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Dobos A, Fodor I | title = Prevalence of Coxiella burnetii in bovine placentas in Hungary and Slovakia: Detection of a novel sequence type - Short communication | journal = Acta Veterinaria Hungarica | volume = 69 | issue = 4 | pages = 303–307 | date = October 2021 | pmid = 34735368 | doi = 10.1556/004.2021.00047 | s2cid = 243762186 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Obaidat MM, Kersh GJ | title = Prevalence and Risk Factors of Coxiella burnetii Antibodies in Bulk Milk from Cattle, Sheep, and Goats in Jordan | journal = Journal of Food Protection | volume = 80 | issue = 4 | pages = 561–566 | date = April 2017 | pmid = 28272921 | pmc = 6489127 | doi = 10.4315/0362-028X.JFP-16-377 }}</ref><ref>{{cite journal | vauthors = Espí A, Del Cerro A, Oleaga Á, Rodríguez-Pérez M, López CM, Hurtado A, Rodríguez-Martínez LD, Barandika JF, García-Pérez AL | display-authors = 6 | title = One Health Approach: An Overview of Q Fever in Livestock, Wildlife and Humans in Asturias (Northwestern Spain) | journal = Animals | volume = 11 | issue = 5 | pages = 1395 | date = May 2021 | pmid = 34068431 | pmc = 8153578 | doi = 10.3390/ani11051395 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Agger JF, Paul S | title = Increasing prevalence of Coxiella burnetii seropositive Danish dairy cattle herds | journal = Acta Veterinaria Scandinavica | volume = 56 | issue = 1 | pages = 46 | date = July 2014 | pmid = 25056416 | pmc = 4115160 | doi = 10.1186/s13028-014-0046-2 | doi-access = free }}</ref>

Infected animals shed the bacteria by three routes - genital discharge, faeces, and milk.<ref>{{cite journal | vauthors = Guatteo R, Beaudeau F, Joly A, Seegers H | title = Coxiella burnetii shedding by dairy cows | journal = Veterinary Research | volume = 38 | issue = 6 | pages = 849–860 | date = November 2007 | pmid = 17903418 | doi = 10.1051/vetres:2007038 | doi-access = free }}</ref>  Excretion is greatest at the time of parturition or abortion, and placentas and aborted fetuses are the main sources of bacteria, particularly in goats.

As ''C. burnetii'' is small and resistant in the environment, it is easily airborne and can be transmitted from one farm to another, even if several kilometres away.<ref>{{cite journal | vauthors = Hawker JI, Ayres JG, Blair I, Evans MR, Smith DL, Smith EG, Burge PS, Carpenter MJ, Caul EO, Coupland B, Desselberger U, Farrell ID, Saunders PJ, Wood MJ | display-authors = 6 | title = A large outbreak of Q fever in the West Midlands: windborne spread into a metropolitan area? | journal = Communicable Disease and Public Health | volume = 1 | issue = 3 | pages = 180–187 | date = September 1998 | pmid = 9782633 | url = https://pubmed.ncbi.nlm.nih.gov/9782633 }}</ref>