Seroprevalence of Tick-borne Encephalitis in Dogs in Northwestern Croatia

Krpeljni encefalitis vektorska je virusna zarazna bolest uzrokovana arbovirusom iz roda Flavivirus, porodice Flaviviridae. U posljednjih deset godina ova zoonoza bilježi porast svoje geografske rasprostranjenosti kao i patogenosti, dok se u nekim područjima re-emergentno pojavljuje pa njen značaj time uvelike raste. U Hrvatskoj se enzootski pojavljuje u sjevernom dijelu, pa je cilj ovog diplomskog rada bio provesti prvo istraživanje o seroprevalenciji KE-a u domaćih životinja, konkretno pasa i usporediti ga s ostalim sličnim istraživanjima u Europi. Korišteni su uzorci prikupljeni iz arhiva Centralnog laboratorija Klinike za unutarnje bolesti Veterinarskog fakulteta u Zagrebu. Istraživanu skupinu čini ukupno 178 pasa, od kojih je 45 pasa mješanaca i 133 čistokrvna psa. Prosječna starost istraživane skupine je 7 godina. Istraživanu skupinu podijelili smo na dvije podskupine s obzirom na namjenu: skupina lovnih i skupina nelovnih pasa. U skupini nelovnih pasa pretraženo je ukupno 167 uzoraka seruma. Prema spolu pretraženo je 82 uzorka seruma mužjaka i 85 ženki. S obzirom na dokaz prethodne infekcije s Babesia spp. pretraženo je 40 uzoraka invadiranih i 127 uzoraka neinvadiranih životinja. Nadalje, u skupini lovnih pasa pretraženo je 11 uzoraka seruma. Prema spolu 7 uzoraka seruma mužjaka i 4 uzorka ženki. S obzirom na dokaz prethodne infekcije Babesia spp. pretraženo je 7 uzoraka invadiranih i 4 uzorka neinvadiranih životinja. Uzorci su pretraženi ELISA metodom s komercijalnim dijagnostičkim kompletom „Immunozym FSME IgG All species“ (Progen Biotechnik, Heidelberg, Njemačka). Utvrđena su dva seropozitivna uzorka što je 1,12% Koncentracije IgG-KE seropozitivnih uzoraka iznose 127 VIEU/ml i 428 VIEU/ml. Rezultati ovoga rada potvrđuju potrebu za daljnjim sličnim istraživanjima u drugim područjima RH, kao i na drugim životinjskim vrstama s ciljem točnijeg utvrđivanja seroprevalencije KE-a. Također, zbog dokazane serokonverzije psi bi se i u RH mogli koristiti kao tzv. sentinel životinje za praćenje rizika od infekcije s KE, što je veoma bitno i iz javnozdravstvenog aspekta.Tick-borne encephalitis (TBE) is vectore borne viral disease caused by arbovirus belonging to genus Flavivirus, family Flaviviridae. In the last ten years, this zoonosis increased its geographical distribution, as well as pathogenicity, while in some areas occures as reemergent disease and its significance is thus greatly increasing. TBE is considered endemic in northern Croatia, so the aim of this diploma thesis was to for the first time in Croatia determine seroprevalence of TBE in domestic animals, particularly dogs and to compare it with other similar studies in Europe. Samples used in this thesis were collected from the archives of the Central laboratory of Department of Internal Medicine, University of Veterinary Medicine, Zagreb. The study included 178 dogs: 45 mongrel dogs and 133 pure bred dogs. The average age of dogs was 7 years. Dogs were devided in to two groups regarding their purpose: group of hunting and non hunting dogs. In the group of non hunting there was total of 167 serum samples. We searched 82 serum samples of males and 85 of females. Regarding the evidence of previous infection with Babesia spp. 40 of searched samples were of infected and 127 samples of uninfected animals. Furthermore, in the group of hunting dogs there were 11 serum samples. We searched 7 serum samples of males and 4 of females. Regarding the evidence of previous infections with Babesia spp. 7 of searched dogs were infected and 4 dogs were uninfected. Samples were examined with ELISA method with a commercial diagnostic kit "Immunozym TBE IgG All species" (Progen Biotechnik, Heidelberg, Germany). The results showed that 1.12% of samples were seropositive to TBE. Two serum concentrations of IgG - KE were positive (127 VIEU/ ml and 428 VIEU/ml). Results of this study confirm the need for further similar studies in other areas of RH, as well on the other animal species so we could more accurately determine seroprevalence of TBE in RH. Because of proven seroconversion, dogs could also be used as sentinel animals for monitoring the risk of infection with TBE, which is also very important from a public health point of view