| Abstract | Cilj ovog prospektivnog seroepidemiološkog istraživanja bio je istražiti dinamiku prokuživanja bakterijom C. burnetii kod profesionalno izloženih osoba u južnom endemskom području Istre u odnosu na sjeverni dio Istarske županije te utvrditi moguću međuzavisnost pojavnosti infekcije koksijelom u ljudi ovisno o prokuženosti u životinja (ovce i koze).
U razdoblju od 2014. do 2016. godine, 156 ispitanika smo jednom godišnje testirali na prisutnost specifičnih protutijela IgG faze II C. burnetii metodom indirektne imunofluorescencije (IFA). Prisutnost protutijela protiv C. burnetii kod 634 ovaca i koza s različitih područja Istarske županije utvrđena je imunoenzimskim indirektnim testom (ELISA).
Sveukupna seroprevalencija ispitanika bila je 64,1%. Na južnom dijelu bilo je 33 (55,9%) seropozitivnih ispitanika, a na sjevernom 67 (69,1%). Praćenjem dinamike titra protutijela kod 88 (88%) seropozitivnih osoba nije došlo do značajnijih promjena u visini titra, dok je kod 9 (9%) ispitanika došlo do gubitka rezidualnog titra, a kod 3 (3%) je zabilježena reinfekcija. Od 59 (38%) seronegativnih osoba, tijekom istraživanja zabilježeno je kod 3 (5%) ispitanika primoinfekcija koksijelom. Na sjevernom dijelu Istre ispitanici su bili prokuženiji u odnosu na ispitanike iz južnog dijela (69,1% : 55,9%), čime je opovrgnuta hipoteza ovog istraživanja. Najznačajni rizični čimbenici za obolijevanje od Q-groznice na području Istre su profesionalna izloženost s omjerom izgleda OR=6,37 (95% CI 2,04-19,86; p=0,001), pušenje cigareta OR=4,97 (95% CI 1,66-14,87; p=0,004), više od 20 godina boravka na farmi OR= 3,63 (95% CI 1.34-9,80; p=0,011) te pripadnost sjevernoj regiji Istre OR=3,22 (95% CI 1,24-8,40; p=0,016). Binarni logistički model seropozitivnog nalaza u ispitanika s obzirom na kontakt sa životinjama (ovce/koze) pokazuje da su veći izgledi za infekciju koksijelom kod onih ljudi koji žive u sjevernom dijelu Istre (OR=3,09), koji su u kontaktu sa životinjama iz većeg stada (OR=2,73), koji rade na farmama s lošijim higijenskim uvjetima (OR=2,56) te koji su u kontaktu s ovcama (OR=2,11).
Granica između južnog endemskog i sjevernog dijela Istre, što se Q-groznice tiče, ne postoji, te se kod bolesnika s nespecifičnom febrilnom bolešću, osobito u kasnu zimu, proljeće i početak ljeta na području cijele Istarske županije treba uvijek diferencijalno dijagnostički misliti na Q-groznicu, osobito kod profesionalno izloženih osoba. |
| Abstract (english) | The aim of this prospective sero-epidemiological study was to investigate the dynamics of naturally acquired immunity to C. burnetii in professionally exposed subjects in the southern endemic part of Istria compared to those from the northern part of the Istrian Region. The second aim was to determine the interdependence of Coxiella infection in humans by reference to immunity in animals (sheep and goats).
156 participants were tested once yearly in the period 2014 – 2016 for the presence of IgG phase II specific antibodies to C. burnetii using the indirect immunofluorescence method (IFA). The presence of antibodies to C. burnetii in 634 sheep and goats from different parts of the Istrian Region was determined by the indirect enzyme immunoassay (ELISA).
The overall seroprevalence of participants was 64,1%. In the southern part there were 33 (55,9%) seropositive subjects and in the norther one there were 67 (69,1%). The monitoring of the dynamics of antibody titre showed no significant changes in titre in 88 (88%) seropositive persons, whereas in 9 (9%) persons the loss of residual titre has been proven and 3 (3%) had reinfection. Of the 59 (38%) seronegative persons, in the course of the study 3 (5%) had a Coxiella primoinfection. In the northern part of Istria acquired immunity was more prevalent compared to the southern part (69,1%:55,9%). Thereby the hypothesis of this study was rejected. The most important risk factors for contracting Q fever in Istria are professional exposure with a OR=6,37 (95% CI 2,04-19,86; p=0,001), cigarette smoking OR=4,97 (95% CI 1,66-14,87; p=0,004), more than 20 years stay on the farm OR= 3,63 (95% CI 1.34-9,80; p=0,011) and residence in the northern part of Istria OR=3,22 (95% CI 1,24-8,40; p=0,016). The binary logistical model of seropositive findings in study subjects with respect to contact with animals (sheep/goats) shows greater probability of Coxiella infection in persons living in the northern part of Istria (OR=3,09), those in contact with animals from a larger herd (OR=2,73), those working on the farms with poor hygienic conditions (OR=2,56) and those being in contact with sheep (OR=2,11). There is no clear boundary between the southern, endemic part and the northern part of Istria regarding the current local epidemiology of Q fever. Therefore, for patients with nonspecific febrile illness, especially during the late winter, spring and at the beginning of summer, the possibility of Q fever should always be considered in the entire Region of Istria. The risk for disease among humans is especially pronounced among professionally exposed persons. |
