Q Fever Guidelines

Updated: Feb 01, 2023
  • Author: Kerry O Cleveland, MD; Chief Editor: John L Brusch, MD, FACP  more...
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Guidelines Summary

In March 2013, the CDC issued the first national guidelines for Q fever recognition, clinical and laboratory diagnosis, treatment, management, and reporting for health-care and public health workers. The guidelines address treatment of acute and chronic phases of Q fever illness in children, adults, and pregnant women and the management of occupational exposures. [44]

Key points for diagnosis and management are discussed below.


Polymerase chain reaction (PCR) of whole blood or serum provides rapid results and can be used to diagnose acute Q fever in the first 2 weeks after symptom onset but before antibiotic administration.

A fourfold increase in phase II immunoglobulin G (IgG) antibody titer by immunofluorescent assay (IFA) of paired acute and convalescent specimens is the diagnostic gold standard to confirm diagnosis of acute Q fever. A negative acute titer does not rule out Q fever because an IFA is negative during the first stages of acute illness. Most patients seroconvert by the third week of illness.

A single convalescent sample can be tested using IFA in patients past the acute stage of illness; however, a demonstrated fourfold rise between acute and convalescent samples has much higher sensitivity and specificity than a single elevated, convalescent titer.

Diagnosis of chronic Q fever requires demonstration of an increased phase I IgG antibody (≥1:1024) and an identifiable persistent infection (e.g., endocarditis)

PCR, immunohistochemistry, or culture of affected tissue can provide definitive confirmation of infection by Coxiella burnetii.

Test specimens can be referred to CDC through state public health laboratories.

Treatment and management

Because of the delay in seroconversion often necessary to confirm diagnosis, antibiotic treatment of acute Q fever should never be withheld pending laboratory tests or discontinued on the basis of a negative acute specimen. In contrast, treatment of chronic Q fever should be initiated only after diagnostic confirmation.

Treatment for acute or chronic Q fever should only be given in clinically compatible cases and not based on elevated serologic titers alone (see Pregnancy section below for exception).

For acute Q fever, doxycycline is the drug of choice, and 2 weeks of treatment is recommended for adults, children aged ≥8 years, and for severe infections in patients of any age.

Children younger than 8 years with uncomplicated acute illness may be treated with trimethoprim/sulfamethoxazole or a shorter duration (5 days) of doxycycline.

Women who are pregnant when acute Q fever is diagnosed should be treated with trimethoprim/sulfamethoxazole throughout the duration of pregnancy.

Serologic monitoring is recommended following acute Q fever infection to assess possible progression to chronic infection. The recommended schedule for monitoring is based on the patient's risk for chronic infection.