The Discovery of Q Fever and Its Cause.

An outbreak of a febrile illness among workers in a slaughterhouse in Brisbane, Australia led E.H. Derrick to discover a new infection, which he labeled Q fever. Almost simultaneously, investigators in Montana discovered a new organism in ticks that caused fever in guinea pigs. Eventually, investigators found that the Q fever and tick microbes were identical. Outbreaks of Q fever occurred in laboratories, and epidemics of it affected both Axis and Allied troops in Europe during World War II, but it was only afterwards that an explanation emerged about what the major reservoir of the organism was and how infection was most commonly transmitted to animals and humans.

Q Fever, Scrub Typhus, and Rickettsial Diseases in Children, Kenya, 2011-2012.

To increase knowledge of undifferentiated fevers in Kenya, we tested paired serum samples from febrile children in western Kenya for antibodies against pathogens increasingly recognized to cause febrile illness in Africa. Of patients assessed, 8.9%, 22.4%, 1.1%, and 3.6% had enhanced seroreactivity to Coxiella burnetii, spotted fever group rickettsiae, typhus group rickettsiae, and scrub typhus group orientiae, respectively.

Coxiella burnetii seroprevalence and risk for humans on dairy cattle farms, the Netherlands, 2010-2011.

Q fever, caused by Coxiella burnetii, is a recognized occupational infection in persons who have regular contact with ruminants. We determined C. burnetii seroprevalence in residents living or working on dairy cattle farms with ≥50 adult cows and identified risk factors for seropositivity. Serum samples from farm residents, including employees, were tested for C. burnetii IgG and IgM; seroprevalence was 72.1% overall and 87.2%, 54.5%, and 44.2% among farmers, spouses, and children, respectively. Risk factors included farm location in southern region, larger herd size, farm employment, birds in stable, contact with pigs, and indirect contact with rats or mice. Protective factors included automatic milking of cows and fully compliant use of gloves during and around calving. We recommend strengthening general biosecurity measures, such as consistent use of personal protective equipment (e.g., boots, clothing, gloves) by farm staff and avoidance of birds and vermin in stables.

The Q fever epidemic in The Netherlands: history, onset, response and reflection.

The 2007-2009 human Q fever epidemic in The Netherlands attracted attention due to its magnitude and duration. The current epidemic and the historical background of Q fever in The Netherlands are reviewed according to national and international publications. Seroprevalence studies suggest that Q fever was endemic in The Netherlands several decades before the disease was diagnosed in dairy goats and dairy sheep. This was in 2005 and the increase in humans started in 2007. Q fever abortions were registered on 30 dairy goat and dairy sheep farms between 2005 and 2009. A total of 3523 human cases were notified between 2007 and 2009. Proximity to aborting small ruminants and high numbers of susceptible humans are probably the main causes of the human Q fever outbreak in The Netherlands. In general good monitoring and surveillance systems are necessary to assess the real magnitude of Q fever.

Jewels in the crown: The Medical Journal of Australia's 10 most-cited articles.

According to data from the Institute for Scientific Information (ISI), the most-cited MJA article is Cade's ground-breaking report on the effect of lithium in mania (1949; 888 citations), followed by Marshall et al's reports on the role of Helicobacter pylori in gastroduodenal disease (1985; 766 and 523 citations, respectively). Others in the "top 10" span decades and disciplines; all have a common grounding in Australian data of global relevance.

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.

Q fever--still a query and underestimated infectious disease.

Coxiella burnetii (C.b.) is a strictly intracellular, Gram-negative bacterium. It causes Q fever in humans and animals worldwide. The animal Q fever is sometimes designated "coxiellosis". This infection has many different reservoirs including arthropods, birds and mammals. Domestic animals and pets, are the most frequent source of human infections. Q fever may appear basically in two forms, acute and chronic (persistent). The latter form of Q fever in animals is characteristic by shedding C.b. into the environment during parturition or abortion. Human Q fever results usually from inhalation of contaminated aerosols originating mostly from tissue and body fluids of infected animals. Q fever may appear in humans either in an acute form accompanied mainly by fever (pneumonia, flu-like disease, hepatitis) or in a chronic form (mainly endocarditis). Diagnosis of Q fever is based on isolation of the agent in cell culture, its direct detection, namely by PCR, and serology. Detection of high phase II antibodies titers 1-3 weeks after the onset of symptoms and identification of IgM antibodies are indicative to acute infection. High phase I IgG antibody titers >800 as revealed by microimmunofluorescence offer evidence of chronic C.b. infection. For acute Q fever, a two-weeks-treatment with doxycycline is recommended as the first-line therapy. In the case of Q fever endocarditis a long-term combined antibiotic therapy is necessary to prevent relapses. Application of Q fever vaccines containing or prepared from phase I C.b. corpuscles should be considered at least for professionally exposed groups of the population. Infections caused by C.b. are spread worldwide and may pose serious and often underestimated health problems in human but also in veterinary medicine. Though during the last decades substantial progress in investigation of C.b. has been achieved and many data concerning this pathogen has been accumulated, some questions, namely those related to the pathogenesis of the disease, remain open.