Summary:Lyme disease is a tick borne zoonotic infection, caused by Borrelia burgdorferi s.l. bacteria. For the transmission of the disease, the presence of ticks is a prerequisite. Lyme borreliosis mostly occurs in people and dogs, but it may occur in other animals. Ticks which carry B. burgdorferi s.l. in Serbia are of the Ixodes ricinus specis. In Serbia, Lyme disease was detected for the first time in the late '80-es. In dogs, clinical symptoms may occur even months after a tick bite, and include weakness, lymphadenopathy, fever, lameness, arthritis, etc. In our survey, we have observed tick and dog populations in the province of Vojvodina (northern part of Serbia). I. ricinus ticks were collected and examined for the presence of B. burgdorferi s.l. in several chosen locations. In addition, blood samples were collected from house dogs and pets from the same locations, and analyzed for the presence of antibodies specific for B. burgdorferi s.l. The results showed a mean infection of ticks of 22.12 %, and a mean seroprevalence of Lyme disease in dogs of 25.81 %. We conclude that in Vojvodina there is an actual risk of Lyme borreliosis for other animals and humans, because of the persistence of B. burgdorferi s.l. in both tick and dog populations.

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To improve the serodiagnosis of Lyme borreliosis (LB) the performances of four tests were evaluated. An indirect immunofluorescent assay based on Borrelia burgdorferi s.s., enzyme-linked immunosorbent assay (ELISA) based on local isolates of Borrelia afzelii and B. burgdorferi s.s., and immunoblot (IB) of B. afzelii were prepared. The serum panels contained 214 serum samples: control group (n=120) and patients at different stages of LB (n=94). The specificity of IB was 96%, of in-house ELISA 93%, and of IFA 89%. In early LB the sensitivity of IFA was 36%, ELISA 67%, and IB 93%. In late-stage LB the sensitivity was: 72% for IFA, 80% for ELISA, and 94% for IB. Comparison of in-house and Behring ELISA showed that the sensitivity of the serological assay could be increased when the test was based on local Borrelia strains. IgM and IgG antibodies from sera of patients with early and late LB most frequently demonstrated reactivity to OspC. The other significant proteins in early LB were: p39, p41 in IgM IB, and p83/100, p39, Osp17 in IgG IB; in late LB: p39, p41 in IgM IB, and p83/100, Osp17, p21 and p43 in IgG IB. Using IB based on local B. afzelii isolates improves the serodiagnosis of early LB in our geographical region.

Cohabitation studies with common carp were conducted to determine whether the Cyprinid Herpes Virus 3 can infect and establish a productive infection in fish species that according to available data, are not susceptible to this virus. In order to examine if other fish species can contribute to further spreading of the virus, goldfish, silver carp, grass carp, prussian carp and tench were exposed to CyHV-3 through cohabitation with infected carp without clinical symptoms. After this period they cohabitated with naive carp for two weeks and were examined for CyHV-3 by PCR. Our results showed that CyHV-3 was present in the organs of these fish species and also in organs of naive carp after two weeks in cohabitation, suggesting that CyHV-3 may cause latent infection, and also that has a potential to infect a broader host range than it was believed before. Our study adds on better understanding of CyHV-3 transmission not just in its primary host, but also suggests the importance of common fish species in polyculture with carp in the epidemiology of CyHV-3. [Projekat Ministarstva nauke Republike Srbije, br. TR31075 i br. TR-31011

We assayed the presence of antibodies specific for Rickettsia typhi, R. akari, and R. conorii in sera of persons from several localities in Serbia with different geographic, climatic, and lifestyle characteristics. Sera from 140 patients with unclear clinical symptoms and 273 healthy persons were tested for the presence of rickettsiae-specific antibodies by indirect immunofluorescence assay. In this study, for the first time we detected the presence of rickettsiae from the spotted fever group in Serbia. We detected the presence of antibodies against R. conorii in the samples from all tested localities. The proportion of positive cases was low in the plain agricultural areas but reached up to 23% in the mountain areas. We also observed a significant number of cases positive for antibodies against R. akari. Antibodies specific for the antigens of R. typhi were detected in only 2 samples from the municipality of Pec (Kosovo region). These findings contribute to the prevalence of Rickettsia species in Southeast Europe. Our study also revealed a dramatic lack of awareness of rickettsioses among medical personnel and pointed to the need for urgent measures that would help improve the current situation in the region.

Ehrlichiosis should be considered in each case where there is a history of tick bite together with the clinical picture (high fever, chills, muscle aches, headache, generalized weakness and malaise, and possible maculopapular rash). The presence of Ehrlichia chaffeensis antibodies was confirmed in a patient with the history of tick bite, appropriate clinical picture and indirect immunofluorescence assay. This confirmed the presence of human monocytotropic ehrlichiosis, a disease that is uncommonly identified in our country.

In Europe, of all the vector transmitted diseases, the occurrence of lyme disease is the one most often registered, and the most significant vector Borrelia burgdorferi is the tick Ixodes ricinus. Both humans and animals contract lyme disease. The risk of the occurrence of lyme disease is in correlation with potential exposure to tick bites and depends on the density of the tick population in the endemic area, the percentage of ticks infected with the cause of lyme disease, the duration and the nature of the activity of the susceptible population in a certain area. The objective of these investigations was to determine the entomological and the ecological risk index, as well as to assess the risk of transmission of the cause of lyme disease in the territory of Vojvodina Province in the Republic of Serbia. Ticks were collected at 12 locations in the South Bačka District of Vojvodina. A total of 1400 ticks were identified up to the level of species. After establishing the infection of ticks with the cause of lyme disease, the entomological and the ecological index was determined for the given regions using microscopic examination in a dark field. Two species of ticks aere identified in this geographic region (Ixodes ricinus and Dermacentor marginatus). Examining I. ricinus, the prevalence of infection B. burgdorferi was established, ranging up to 33.1%. The ecological risk index indicates that there is a potential risk of humans and animals becoming infected at 8 localities. It was determined for 3 localities that there is a definite actual risk of the transferrence of causes of lyme disease

Lyme disease is a multisystemic disease, zoonotic in nature, caused by the Borrelia burgdorferi sensu lato complex. In the continent of Europe, these spirochetes are predominantly transmitted by ticks of the genus Ixodes. Small mammals and birds have particular significance as reservoirs of the cause of lyme disease. The objective of these epidemiological investigations was to determine the value of IgG seroprevalence to Borrelia burgdorferi and to secure the geographic distribution of seropositive dogs in Vojvodina. The investigations covered 135 dogs that were not vaccinated against lyme disease. The indirect ELISA test was used to determine IgG prevalence to Borrelia burgdorferi antigens. Reactive blood serums of dogs were tested again using the rapid immunochromatographic and immunoblot test. A seroprevalence of G class antibodies to antigens of lyme disease causes of 8.1% (11/135) was established in the examined dog population of Vojvodina. The biggest number of positive results was recorded for the South Bačka District. The presented value for the seroprevalence of anti-Borrelia burgdorferi antibodies in the dog population indicates the exhistence of a significant risk of humans becoming infected with the cause of lyme disease in Vojvodina