Seroprevalence estimate and risk factors for Coxiella burnetii infections among humans in a highly urbanised Brazilian state

Abstract

Background Q fever is among the top 13 global priority zoonoses, however, it is still neglected and under-reported in most of the world, including Brazil. Thus, we evaluated the seroprevalence of and the risk factors for Coxiella burnetii infections in humans from Minas Gerais, a highly urbanised Brazilian state. Methods Coxiella burnetii was searched for patient samples (n=437), which were suspected of then later confirmed as negative for dengue fever, by the indirect immunofluorescence technique and real-time PCR. Risk factors for infections and spatial clusters for both C. burnetii-seropositive individuals and livestock concentration were evaluated. Results We found that 21 samples (4.8%; 95% CI 3.0 to 7.2%) were reactive for at least one class of anti-C. burnetii antibodies (titer of ≥64), with rural residence (p=0.036) being a risk factor. Also, two spatial clusters of seropositivity were found within a significant area by Scan, and a probable relationship between the Scan result and the livestock concentration by area was found. Conclusions Seropositive individuals were associated with rural residence, with a likely relationship with the livestock concentration. Thus, this study establishes baseline figures for C. burnetii seroprevalence in humans in a state of Brazil, allowing the monitoring of trends and setting of control targets, as well as more representative longitudinal and risk analysis studies.

Q fever and coxiellosis in Brazil: an underestimated disease? A brief review

“…In 2021, in Minas Gerais, 437 patients suspected and later confirmed to be negative for dengue were evaluated, 4.8% of whom were seropositive for anti-C. burnetii antibodies on the IFA test, with titers ranging between 64 and 128 (phase I and phase II). This study showed that rural residence was a risk factor for QF in that region (Meurer et al, 2022).…”

Tick-Borne-Agents Detection in Patients with Acute Febrile Syndrome and Ticks from Magdalena Medio, Colombia

“…Specifically, a study conducted in Korea, where 592 blood samples were collected from animals, identified this microorganism in 22.7% of goats, 16.4% of dairy cattle, 15.2% of beef cattle, 6.0% of Boer goats, and 5.2% of horses [ 34 ], suggesting that these mammals may play an important role as reservoirs for this microorganism. Moreover, other studies have described C. burnetii seropositive individuals associated with rural residences, with an alleged relationship with the livestock number, finding the bacteria in 4.8% of the samples evaluated [ 35 ].…”

Q Fever: characteristics and reports of an important neglected zoonosis in Brazil / Febre Q: características e relatos de uma importante zoonose negligenciada no Brasil

“…Although less frequent, it is also possible to mention the gender, as there are reports that men have larger probability to be positive for antibodies against C. burnetii or to be diagnosed with Q fever. 9,25 According to results presented by Meurer et al 26 , it is possible to deduce that living in the rural area increases the chances of exposition to Q fever causing pathogen. In addition, according to Borawski et al 27 , Q fever should be considered in the differential diagnosis in cases of fever involving agriculturists and veterinarians who have contact with bovine cattle.…”