Unusual aspects of acute Q fever-associated hepatitis

Familial Q fever clustering with variable manifestations imitating infectious and autoimmune disease

Q fever, caused by Coxiella burnetii, can present as an outbreak of acute disease ranging from asymptomatic disease, pneumonia, hepatitis or fever of unknown origin, which can progress to a chronic disease, most frequently endocarditis. The occurrence of Q fever within families is rarely described, and in most cases presents with uniform acute disease manifestations. Here we present a familial cluster of Q fever presenting as highly variable synchronous manifestations in four of five family members, including prolonged fever of unknown origin, asymptomatic carrier state, hepatitis, and chronic endocarditis developing in the absence of previous symptoms. This case series highlights the possibility of Q fever developing in cohabitated individuals with highly variable symptoms masking the common disease etiology. Screening of all exposed individuals, even those not clinically suspected to be infected, may enable to better identify, treat and prevent progression to chronic disease.

Understanding the presence of false-positive antibodies in acute hepatitis

Although false-positive antibodies (FPAs) have been well described in chronic hepatitis C virus (HCV), this has not been evaluated in acute viral hepatitis. Patients with acute viral hepatitis underwent antibody testing for other causes of liver disease and sexually transmitted diseases. Those with antibody positivity underwent confirmatory testing and monitoring. Patients with FPAs were compared with patients with acute hepatitis C infection without FPAs. In total 7 of 24 patients (29%) had FPAs. FPAs during acute viral hepatitis are associated with higher IgM levels and higher ESR in acute HCV. This has both mechanistic and clinical implications and should be evaluated further.

Pseudoepidemic of Q Fever at an Animal Research Facility

Serum samples from people exposed to sheep at a research facility were evaluated by a commercial laboratory and resulted in an overall Coxiella burnetii seroprevalence of 75%. We interviewed individuals to determine exposure history and compatible illness, and retested their sera. Analysis indicated that the commercial laboratory was misinterpreting its results; when corrected, the seroprevalence dropped to 27%. Test kits of the brand used by the commercial laboratory gave equivalent results to the in-house CDC assay when tested in parallel at CDC. Upon final analysis, only the attending veterinarian was confirmed as a Q fever case. This event resulted in increased risk reduction protocols at the research facility and improved public health communication among health authorities. This pseudoepidemic resulted from a lapse in laboratory quality control for testing. Similar errors can be avoided through standardization and improved review of laboratory procedures.

Q fever endocarditis in HIV-infected patient

We describe a case of Q fever endocarditis in an HIV-infected patient. The case was treated successfully with valvular replacement and a combination of doxycycline and hydroxychloroquine. We review the current literature on Q fever endocarditis, with an emphasis on the co-infection of HIV and Coxiella burnetii.

Q fever in humans and animals in the United States

Coxiella burnetii, the etiologic agent of Q fever, is a worldwide zoonotic pathogen. Although Q fever is present in the United States, little is known about its current incidence or geographic distribution in either humans or animals. Published reports of national disease surveillance, individual cases, outbreak investigations, and serologic surveys were reviewed to better characterize Q fever epidemiology in the United States. In national disease surveillance reports for 1948-1986, 1,396 human cases were reported from almost every state. Among published individual case reports and outbreak investigations, occupational exposures (research facilities, farm environments, slaughterhouses) were commonly reported, and sheep were most frequently implicated as a possible source of infection. In studies conducted on specific groups, livestock handlers had a significantly higher prevalence of antibodies to C. burnetii than did persons with no known risk. Animal studies showed wide variation in seroprevalence, with goats having a significantly higher average seroprevalence (41.6%) than sheep (16.5%) or cattle (3.4%). Evidence of antibody to C. burnetii was reported among various wild-animal species, including coyotes, foxes, rodents, skunks, raccoons, rabbits, deer, and birds. This literature review suggests that C. burnetii is enzootic among ruminants and wild animals throughout much of the United States and that there is widespread human exposure to this pathogen. Sheep and goats appear to be a more important risk for human infection in the United States than cattle or wild animals, and research studies examining the natural history and transmission risk of Q fever in sheep and goats in this country should be encouraged.

Tularemia and Q fever

The zoonotic infections caused by Francisella tularensis and Coxiella burnetii, tularemia and Q fever, respectively, are two less commonly encountered clinical illnesses that are becoming increasingly recognized as epidemiologically important human diseases. The prevalence of tularemia and Q fever can be positively impacted by increased awareness of the clinical entities that arise from infection by these arthropod-borne organisms. Improved recognition of these clinical syndromes will lead to greater diagnostic accuracy in recognizing these diseases in patients. Ultimately, more stringent measures to prevent infection may be required, through raising public awareness, since current therapeutic regimens for these two diseases are limited, and knowledge of the pathogenesis of these two organisms are still in developing stages.