Doctoral theses
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| Identifier |
uch.med.phd//2001loukaides |
| Title |
Επιδημιολογική έρευνα του πυρετού Q (C.Burnetti) στον ζωικό και ανθρώπινο πληθυσμό της Κύπρου με τη χρήση του συστήματος μηχανογραφημένης χαρτογράφησης |
| Creator |
Loukaides, Feidias
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| Abstract |
Q Fever in human and animals is endemic in almost all the Mediterranean region. In Cyprus although previous serosurveys reveled low seropositivity for C.burnettii among human and animal population, no previous study on the epidemiology of Q Fever existed. It was a need for a study to be undertaken to investigate all the epidemiological aspects related to the above disease using as tools the Geographical Information System and Molecular Biology Techniques in order to increase the power of the study. The main objectives of the study were: 1. Descriptive epidemiological study of Q Fever in Cyprus in both humans, animals and ticks in order to estimate the magnitude of the disease. 2. Analytical epidemiological study in high risk regions in order to investigate all the epidemiological aspects which are related to the disease transmission to humans. 3. Surveillance of Q Fever in humans and animals to detect acute cases of the disease and assess the pathogenicity of C.burnettii. The whole study was divided in 3 phases. Phase 1. In this phase of the study the following were included: - Seroepidemiological study in humans and animals - Detection of C.burnettii in ticks - Computerized mapping program of Cyprus The main objectives were: · Estimate the seropositivity in human and animal population · Asses the risk factors of seropositivity · Detection of endemic areas · Detection of "high risk as regions" To estimate the needed sample for the serosurvey the EPI-INFO program and the Stratified Population Survey Sampling Method was used. The sample was estimated using expected prevalence as found in other studies in the Mediterranean region and 95% confidence interval. Ticks were also collected from animal population. A detailed questionnaire was used to obtain from animal owners regarding possible risk factors for seropositivity. Immunofluorescene Assay (IFA) was used to examine sera for antibodies against C.burnettii. Shell Vial Technique was applied to isolate intracellular presence of C.burnettii while PCR, nested PCR and RFLP were used to detect C.burnettii from ticks. Using the Computerized Mapping Program (CMP) a country map was created with the facility of zoom of the selected areas with all the information needed for the study allowing the visualization of the seropositivity. The seropositivity against C.burnettii for the whole human population of Cyprus was estimated 52.7% using 1/60 titre as a cut of IgG antibodies while 7.5% had a titre 1/25 for IgM antibodies. Goats' seropositivity was estimated 48.1% sheep 18.4% and bovine 24%. Eleven out of 141 ticks were found positive for C.burnettii. Seropositivity was found higher among the adults and in agricultural areas. Moreover, it was related with occupation. Also a strong association was revealed between animal contacts (goat and sheep) and their seropositivity to C.burnettii. The relative risk was higher when animal abortion or tick infestation was mentioned. Phase 2. During this phase after the detection of two high-risk regions analytical epidemiological study in human and animals was conducted. Moreover, surveillance of clinical cases in human and animals was established for the two high-risk regions and the computerized mapping program of Cyprus was used in local distribution. The main objectives were: · to asses risk factors for conducting the disease · to detect clinical cases in human and animals · to asses the clinical spectrum of the disease · to estimate the ratio between clinical cases and seropositivity Analytical epidemiological study in the villages Kotsiatis and Paramali (high risk regions) was contacted. The total population of Kotsiatis was 150 inhabitants while the population of Paramali was 198 inhabitants. All population of the two villages was asked to participate in the study. About 79 individuals from Kotsiatis and 121 from Paramali participated in the study. 10% of the animals owned by the participants were randomly sampled. The size of the random sample was calculated using the results of the first phase. Detailed questionnaires were also used to obtain information. The negative individuals, humans and animal of the two villages under study, were followed up for one year by monthly visits to detect clinical cases of Q Fever. Moreover, all participants and animals under study were tested at the end of the follow up period to estimate how many became seropositive without clinical symptoms. The seropositivity of the human population of Kotsiatis was estimated 59.5% and for the population of Paramali 52.9% while the animal population's seropositivity was 43.3% for the animals of Kotsiatis and 28.7% for the animals of Paramali. 13 individuals from the two villages were suspected for Q Fever while only two were laboratory confirmed. The 2nd serological test after one year proved that a significant percentage of the participants became seropositive. Important factor for the transmission from animals to animals and from animals to humans for C.burnettii proved to be the tick infested goats and sheep. Phase 3. During the third phase, surveillance of Q Fever was implemented in the whole island in order to detect human and animal cases. Case definitions for suspected cases were prepared and disseminated to the hospitals all over Cyprus in order to collect the suspected cases of Q Fever to be tested serologically and by shell vial technique. The enhanced surveillance lasted one year. Following the case definition in hospitals, 120 individuals were classified as suspected for Q Fever and 3 of them were Laboratory confirmed as Q Fever. C.burnettii was isolated by shell vial technique. C.burnettii was also isolated from two goats and one sheep, which aborted during the surveillance period. Conclusions: · High seropositivity in humans · High seropositivity in goat and sheep. Significantly higher in goats. · Detection of C.burnettii in a relatively high percentage of ticks · Ticks infestation of goats and sheep are important in the epidemiology of Q Fever in Cyprus · Clinical cases of Q Fever were not previously diagnosed because of decreased clinical suspicion · The seropositivity estimated in epidemiological studies is not indicative of the incidence of acute cases of Q Fever since the majority of the seropositive humans and animals are subclinical cases · Using the Computerized Mapping Program the "high risk region" can be detected and surveillance can be achieved
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| Issue date |
2001-01-01 |
| Date available |
2001-02-07 |
| Collection
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School/Department--School of Medicine--Department of Medicine--Doctoral theses
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Type of Work--Doctoral theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/b/c/5/metadata-dlib-2001loukaides.tkl
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| Views |
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