Editing Q fever (section)

== Signs and symptoms ==
The incubation period is usually two to three weeks.<ref name="Brunette-2011-p270" /> The most common manifestation is [[flu-like symptoms]]: abrupt onset of [[fever]], [[malaise]], [[diaphoresis|profuse perspiration]], severe [[headache]], [[myalgia|muscle pain]], [[Arthralgia|joint pain]], [[Anorexia (symptom)|loss of appetite]], upper respiratory problems, dry cough, [[Pleurisy|pleuritic pain]], chills, [[mental confusion|confusion]], and gastrointestinal [[symptoms]], such as [[nausea]], vomiting, and [[diarrhea]]. About half of infected individuals exhibit no symptoms.<ref name="Brunette-2011-p270">{{cite book|chapter=Q Fever| veditors = Brunette GW, McQuiston J, etal |title=CDC Health Information for International Travel: The Yellow Book|publisher=Oxford University Press|year=2011|isbn=978-0-19-976901-8|page=[https://archive.org/details/cdchealthinforma0000unse/page/270 270]|chapter-url=https://books.google.com/books?id=5vCQpr1WTS8C&pg=PA270| vauthors = Anderson A |url-access=registration|url=https://archive.org/details/cdchealthinforma0000unse/page/270}}</ref>

During its course, the disease can progress to an [[atypical pneumonia]], which can result in a life-threatening [[acute respiratory distress syndrome]], usually occurring during the first four to five days of infection.<ref name="The Lecturio Medical Concept Library">{{cite web|title=Coxiella/Q Fever|url=https://www.lecturio.com/concepts/coxiella-q-fever/|url-status=live|archive-url=https://web.archive.org/web/20210515174110/https://www.lecturio.com/concepts/coxiella-q-fever/|archive-date=2021-05-15|access-date=7 July 2021|website=The Lecturio Medical Concept Library}}</ref>

Less often, Q&nbsp;fever causes (granulomatous) [[hepatitis]], which may be asymptomatic or become symptomatic with malaise, fever, [[Hepatomegaly|liver enlargement]], and pain in the right upper quadrant of the [[abdomen]]. This hepatitis often results in the [[elevated transaminases|elevation of transaminase values]], although [[jaundice]] is uncommon. Q fever can also rarely result in [[retinal vasculitis]].<ref>{{cite journal | vauthors = Kuhne F, Morlat P, Riss I, Dominguez M, Hostyn P, Carniel N, Paix MA, Aubertin J, Raoult D, Le Rebeller MJ | display-authors = 6 | title = [Is A29, B12 vasculitis caused by the Q fever agent? (Coxiella burnetii)] | language = fr | journal = Journal Français d'Ophtalmologie | volume = 15 | issue = 5 | pages = 315–321 | date = 1992 | pmid = 1430809 | trans-title = Is A29, B12 vasculitis caused by the Q fever agent? (Coxiella burnetii) | oclc = 116712679 }}</ref>

The chronic form of Q&nbsp;fever is virtually identical to [[endocarditis]] (i.e. [[inflammation]] of the inner lining of the heart),<ref name="pmid16757641">{{cite journal | vauthors = Karakousis PC, Trucksis M, Dumler JS | title = Chronic Q fever in the United States | journal = Journal of Clinical Microbiology | volume = 44 | issue = 6 | pages = 2283–2287 | date = June 2006 | pmid = 16757641 | pmc = 1489455 | doi = 10.1128/JCM.02365-05 }}</ref> which can occur months or decades following the infection. It is usually fatal if untreated. However, with appropriate treatment, the mortality falls to around 10%.{{citation needed|date=May 2021}}

A minority of Q fever survivors develop [[Q fever fatigue syndrome]] after acute infection, one of the more well-studied [[post-acute infection syndrome]]s. Q fever fatigue syndrome is characterised by [[post-exertional malaise]] and debilitating fatigue. People with Q fever fatigue syndrome frequently meet the diagnostic criteria for [[myalgic encephalomyelitis/chronic fatigue syndrome]] (ME/CFS). Symptoms often persist years after the initial infection.<ref name="pmid35585196">{{cite journal |vauthors=Choutka J, Jansari V, Hornig M, Iwasaki A |date=May 2022 |title=Unexplained post-acute infection syndromes |url= |journal=Nature Medicine |volume=28 |issue=5 |pages=911–923 |doi=10.1038/s41591-022-01810-6 |pmid=35585196|s2cid=248889597 |doi-access=free }}</ref>