Infectious Disease Compendium

Coxiella burnetti aka Q fever

Microbiology

Gram negative pleomorphic coccobacillus; lives in phagolysosomes. And you think your apartment is located in a bad neighborhood.

Epidemiologic Risks

Exposures to cows, sheep, and goats, European rabbits and other animals as well. Especially if the patient is exposed to placentas; it can survive in soil for a long period of time. Being seen by the (few) troops returning from Iraq (along with Leishmania and very resistant Acinetobacter). It can also be found in filth flies (PubMed). Time flies like an arrow, filth flies like a dung pile. So don't be eating a filth fly.

Common in veterinarians (22% of those tested). Risk factors included age >46 years, routine contact with ponds, and treatment of cattle, swine, or wildlife (PubMed).

May even be in seals in Greenland.  And don't stand under 3-toed sloths, the may be excreting Coxiella on you (PubMed).

There have been outbreaks of Q fever by fools drinking raw milk (PubMed).

And even weirder?  This is a wack-a-loon therapy whereby people get injected with "fetal sheep cells" and with it Q fever (PubMed) as part of live cell therapy.  Why anyone would think injection embryonic cells from cows, sheep or sharks is a good idea is beyond me.

Syndromes

Fever (self limited), pneumonia with headaches (in a series from New Zealand, headache was the predominant presenting symptom, leading to a meningitis evaluation rather than a pneumonia presentation) and hepatitis (has a donut cell on histopathology), endocarditis (culture negative).

Oddly, 25% of cases of community acquired pneumonia in French Guiana are due to this bug; they do not speculate as to why (PubMed).

Chronic Q fever is usually endocarditis; risks include valvular surgery, vascular prosthesis, aneurysm, renal insufficiency, and older age (PubMed) (PubMed).

Patients who are older or who have valvulopathy are at high risk for endocarditis and will benefit from a year of doxycycline and hydroxychloroquine prophylaxis (PubMed).

Immunoglobulin G anticardiolipin antibodies predicts progression to Q fever endocarditis (PubMed) and is common (PubMed).

The diagnosis of endocarditis is often made serologically as serology goes from phase II to phase I (yes, its backwards) and this can take three months so patients with acute Q fever need long term serologic follow up (PubMed).

There is a post infectious fatigue after Q fever (as with many infections) that does NOT respond to doxycycline but does get better with cognitive-behavioral therapy (PubMed).

Treatment

Doxycycline is the treatment of choice followed by quinolones or macrolides. Add rifampin for synergy.

From CDC: Diagnosis and Management of Q Fever — United States, 2013

Acute Q fever: Doxycycline 100 bid x 14 d.

Endocarditis: Doxycycline 100 mg twice a day and hydroxychloroquine 200 mg three times a day ≥18 months

Endocarditis therapy is perhaps forever.

Noncardiac organ disease: Doxycycline 100 mg twice a day and hydroxychloroquine 200 mg three times a day.

Postpartum with serologic profile for chronic Q fever: Doxycycline 100 mg twice a day and hydroxychloroquine 200 mg three times a day ≥12 months

Notes

There was a cool case of four guys playing poker in a garage where a cat was giving birth. Three of the 4 came down with Q fever.