An analysis of Q fever patients 6 years after an outbreak in Newport, Wales, UK

Abstract

Six years after acute Q fever, some patients had become seronegative but none contained viable C. burnetii or its DNA in their PBMC.

Strategies for early detection of chronic Q‐fever: a systematic review

“…In the reference lists of these articles, we identified another 12 references as possibly relevant. Additionally, one not yet cited article that did not show up in the search strategy was added to the full‐text assessment step . Five full‐text articles (two French, two Japanese and one Ukrainian) could not be retrieved from three different libraries.…”

“…All nine studies with follow‐up of known acute Q‐fever cases performed during an epidemic had well‐defined inclusion criteria . For studies of endemic cases and articles describing a (reference) laboratory cohort, the inclusion of cases was well defined in four studies , while in three studies it was unclear where cases were derived from .…”

Coxiella burnetiiseroprevalence and risk factors in sheep farmers and farm residents in The Netherlands

“…Those with IgM phase II antibodies were designated as ‘relatively recent infections’ and included possible current infections. The term ‘relatively recent’ was chosen as IgM phase II is found to persist in the majority of cases for 1 year post-infection and may even persist up to 4 years post-infection [20, 21] (C. C. H. Wielders, personal communication). Seropositives without IgM phase II antibodies were designated as ‘past infections’.…”

Long-Term Immune Responses to Coxiella burnetii after Vaccination

“…The mechanism by which C. burnetii is cleared from the blood is not known, but the timing correlates well with the development of immune responses (5). Although recent reports have suggested that C. burnetii DNA and antigen can be detected years after an acute infection, viable organisms are thought to be eliminated more quickly (6,7). However, the time required for complete clearance of viable C. burnetii in humans is not known.…”

“…Thus, greater than 20% of acute Q fever patients could become seronegative 3 to 4 years after having the disease. Indeed, an analysis of Q fever patients in Australia 6 years after an outbreak found that 7/38 (18.4%) had become seronegative (7). A study of antibody responses in people vaccinated against Q fever found that only 60% had positive titers 20 months after vaccination, whereas 90% had detectable cellular immune responses (11).…”