Incidence Estimates of Acute Q Fever and Spotted Fever Group Rickettsioses, Kilimanjaro, Tanzania, from 2007 to 2008 and from 2012 to 2014

Q fever and spotted fever group rickettsioses (SFGR) are common causes of severe febrile illness in northern Tanzania. Incidence estimates are needed to characterize the disease burden. Using hybrid surveillance—coupling case-finding at two referral hospitals and healthcare utilization data—we estimated the incidences of acute Q fever and SFGR in Moshi, Kilimanjaro, Tanzania, from 2007 to 2008 and from 2012 to 2014. Cases were defined as fever and a four-fold or greater increase in antibody titers of acute and convalescent paired sera according to the indirect immunofluorescence assay of Coxiella burnetii phase II antigen for acute Q fever and Rickettsia conorii (2007–2008) or Rickettsia africae (2012–2014) antigens for SFGR. Healthcare utilization data were used to adjust for underascertainment of cases by sentinel surveillance. For 2007 to 2008, among 589 febrile participants, 16 (4.7%) of 344 and 27 (8.8%) of 307 participants with paired serology had Q fever and SFGR, respectively. Adjusted annual incidence estimates of Q fever and SFGR were 80 (uncertainty range, 20–454) and 147 (uncertainty range, 52–645) per 100,000 persons, respectively. For 2012 to 2014, among 1,114 febrile participants, 52 (8.1%) and 57 (8.9%) of 641 participants with paired serology had Q fever and SFGR, respectively. Adjusted annual incidence estimates of Q fever and SFGR were 56 (uncertainty range, 24–163) and 75 (uncertainty range, 34–176) per 100,000 persons, respectively. We found substantial incidences of acute Q fever and SFGR in northern Tanzania during both study periods. To our knowledge, these are the first incidence estimates of either disease in sub-Saharan Africa. Our findings suggest that control measures for these infections warrant consideration.

Q Fever Vaccine Development: Current Strategies and Future Considerations

Q fever is a zoonotic disease caused by the intracellular pathogen Coxiella burnetii. This disease typically manifests as a self-limiting, febrile illness known as acute Q fever. Due to the aerosol transmissibility, environmental persistence, and infectivity of C. burnetii, this pathogen is a notable bioterrorism threat. Despite extensive efforts to develop next-generation human Q fever vaccines, only one vaccine, Q-Vax®, is commercially available. Q-Vax® is a phase I whole-cell vaccine, and its licensed use is limited to Australia, presumably due to the potential for a post-vaccination hypersensitivity response. Pre-clinical Q fever vaccine development is a major area of interest, and diverse approaches have been undertaken to develop an improved Q fever vaccine. Following a brief history of Q fever vaccine development, current approaches will be discussed along with future considerations for an improved Q fever vaccine.

“Acute Q fever with dermatologic manifestations, molecular diagnosis, and no seroconversion”

We herein described a case of acute infection by Coxiella burnetii (acute Q fever) that started with a short incubation period and showed prominent dermatological manifestations and unusual serological behavior. The infection was confirmed by molecular detection through real-time PCR using genomic DNA collected from peripheral blood.

Acute Q fever in third trimester pregnancy

A 29-year-old gravida 2 para 1 woman presented at 29 weeks gestation with fevers, back pain, thrombocytopenia and hepatitis. PCR testing of blood samples detected Coxiella burnetii and paired serology later confirmed the diagnosis of acute Q fever in pregnancy. The patient was treated empirically with oral clarithromycin and experienced a symptomatic and biochemical improvement. Therapy was changed to oral trimethoprim/sulphamethoxazole but was complicated by a delayed cutaneous reaction, prompting recommencement of clarithromycin. Therapy continued until delivery of a healthy girl at 39 weeks and 3 days. Q fever in pregnancy is likely under-reported and is associated with the development of chronic infection and obstetric complications. Treatment with clarithromycin is an alternative to trimethoprim/sulphamethoxazole in the setting of drug intolerance.

Epidemiological, clinical and laboratory features of acute Q fever in a cohort of hospitalized patients in a regional hospital, Israel, 2012-2018

Introduction Acute Q fever is endemic in Israel, yet the clinical and laboratory picture is poorly defined. Methods A retrospective study reviewing the medical records of acute Q fever patients, conducted in a single hospital in the Sharon district, Israel. Serum samples from suspected cases were preliminary tested by a qualitative enzyme immunoassay (EIA). Confirmatory testing at the reference laboratory used an indirect immunofluorescence assay (IFA). Positive cases were defined as fever with at least one other symptom and accepted laboratory criteria such as a single-phase II immunoglobulin G (IgG) antibody titer ≥1:200. Cases not fulfilling these criteria and in which acute Q fever was excluded, served as a control group. Results Between January 2012 and May 2018, 484 patients tested positive. After confirmatory testing, 65 (13.4%) were positive for acute Q fever (with requisite clinical picture), 171 (35.3%) were definitely not infected, the remaining 248 were excluded because of past/chronic/undetermined infection. The average age was 58 years and 66% were males. Most resided in urban areas with rare animal exposure. Pneumonia was seen in 57% of cases and a combination with headache/hepatitis was highly suggestive of acute Q fever diagnosis. Syncope/presyncope, fall and arthritis were more common in acute Q fever cases. Laboratory indexes were similar to the control group, except for erythrocyte sedimentation rate (ESR) which was more common and higher in the study group. Conclusion Acute Q fever in the Sharon district could be better diagnosed by using a syndromic approach in combination with improved rapid diagnostic testing.

The diagnostic challenge of acute Q fever endocarditis

A 79-year-old man was admitted to our ward with symptomatic heart failure 2 months after aortic valve replacement due to severe aortic stenosis. On the third day following admission, he became febrile (>38°C) while manifesting an increase in inflammatory markers. Endocarditis was suspected despite negative blood cultures. Echocardiogram (transthoracic and transesophageal) did not describe any vegetations. No hypermetabolic lesions were described on the Positron emission tomography scan. Empirical antibiotics were started but the fever persisted. Serologies revealed a Coxiella burnetii IgG phase II titre of 1:800, high erythrocyte sedimentation rate. Positive antinuclear antibodies, antibeta2 IgM and anticardiolipin supported a diagnosis of acute Q fever endocarditis. Doxycycline and hydroxychloroquine were started with total resolution of symptoms. This case illustrates the difficulty of diagnosing Q fever endocarditis during its acute phase, not only because vegetations can be minimal or absent, a challenge that is further compounded by a complex presentation of immunological markers.

Epidemiological investigation and physician awareness regarding the diagnosis and management of Q fever in South Korea, 2011 to 2017

Background In South Korea, the number of Q fever cases has rapidly increased since 2015. Therefore, this study aimed to characterize the epidemiological and clinical features of Q fever in South Korea between 2011 and 2017. Methods/Principal findings We analyzed the epidemiological investigations and reviewed the medical records from all hospitals that had reported at least one case of Q fever from 2011 to 2017. We also conducted an online survey to investigate physicians’ awareness regarding how to appropriately diagnose and manage Q fever. The nationwide incidence rate of Q fever was annually 0.07 cases per 100,000 persons annually. However, there has been a sharp increase in its incidence, reaching up to 0.19 cases per 100,000 persons in 2017. Q fever sporadically occurred across the country, with the highest incidences in Chungbuk (0.53 cases per 100,000 persons per year) and Chungnam (0.27 cases per 100,000 persons per year) areas. Patients with acute Q fever primarily presented with mild illnesses such as hepatitis (64.5%) and isolated febrile illness (24.0%), whereas those with chronic Q fever were likely to undergo surgery (41.2%) and had a high mortality rate (23.5%). Follow-up for 6 months after acute Q fever was performed by 24.0% of the physician respondents, and only 22.3% of them reported that clinical and serological evaluations were required after acute Q fever diagnosis. Conclusions Q fever is becoming an endemic disease in the midwestern area of South Korea. Given the clinical severity and mortality of chronic Q fever, physicians should be made aware of appropriate diagnosis and management strategies for Q fever.