Q fever is an acute illness often accompanied by pneumonia which results from infection with a form of Rickettsia. The first human cases of the disease were observed in Australia in 1933. Since they originated in Queensland, the infection was named “Q fever.” Now a similar organism has been isolated from ticks captured in Montana and cases have been found in other areas of the United States.
Human beings are highly susceptible to Q fever; from 25 to 40 per cent of those exposed may be attacked by the disease. The condition was found much more often in Australia among people exposed to cattle. Before 1946 the disease was rare in the United States but has now been found particularly in epidemics in stockyards such as the one in Amarillo, Texas, in Chicago, and among dairymen in Los Angeles county. Workers in research institutes have frequently been infected.
From twelve to twenty-six days after exposure, the disease comes on with symptoms like those seen in other Rickettsial diseases. The two striking features that make Q fever different from other infections with Rickettsia is the absence of any characteristic rash and the almost invariable presence of pneumonia. However, pulmonary symptoms are often mild or absent. About one-half the patients have aches in the chest. X-ray of the chest shows that the lungs have been infected in at least 90 per cent of the cases.
Q fever may be confused with primary virus pneumonia, with tuberculosis, with psittacosis or infected bird fever, and must also be distinguished from ordinary influenza, sinusitis, undulant fever, dengue, and other Rickettsial infections.
Here again aureomycin, chloromycetin, and terramycin have been found useful in treatment. Relapses are rare. Most of the patients recover. Thus far only some eight or ten deaths have occurred among perhaps 1,000 cases that have been reported in medical writings.
*14/318/5*