Abstract
Q fever is a zoonotic infectious disease caused by the Coxiella burnetii bacterium. It is an obligate intracellular pathogen with a high infection capacity
that proliferates exclusively in an acidified medium, forming a lysosome-like vacuole.
It presents a peculiar phenomenon called “antigenic phase variation,” produced by
a modification in the complexity of the membrane lipopolysaccharides. Q fever can
be found worldwide and presents variable clinical features and geographical distribution.
It mostly affects people in rural areas who are in contact with animals. The most
common type of transmission to humans is via the inhalation of aerosols containing
the pathogen, especially those formed from placental derivatives. Wild animals, domestic
animals, and ticks are the principal reservoirs.
Diagnosis is mainly made by indirect methods such as serology or by direct methods
such as microbiological cultures or tests that detect the specific DNA. Typically,
there are two clinical presentations: the acute disease, which is more frequent and
often asymptomatic, and a persistent focalized infection in 4 to 5% of patients, generally
with a poor evolution. Treatment of the acute form in both children and adults consists
of administering doxycycline, while persistent focalized infection should be treated
with at least two antibiotics, such as doxycycline and hydroxychloroquine. Several
measures should be undertaken to minimize exposure among people working with animals
or handling birth products. Different vaccines have been developed to prevent infection,
though few data are available.
Keywords
Coxiella burnetii
- Q fever - epidemiology - pathogenesis - antigenic phase variation - diagnosis -
treatment
