In Romania, anthropozoonoses, and in this nosological context, human viral neuro-infections with incidental transmission by active vectors with natural foci, may be considered infectious diseases with endemic emergence. Since 1996, the form of manifestation of the epidemiological process by viral meningitis and meningoencephalitis, the etiological structure of morbidity and the problem of natural foci have required the implementation of an effective epidemiological survey strategy. This paper includes the results of an epidemiological survey and the general population seroepidemiological evaluation of acute and historic infections, identified as arboviral TBE-CEE neuro-infections.
Material and method: In the interval 1999-2006, the following aspects were studied: an endemic episode of 37 cases of TBE-CEE neuro-virus infection in a rural population. The epidemiological inquiry was conclusive for the transmission of infection by goat milk from highly tick infested animals, in a habitat with identified natural sylvatic and peridomestic foci; an endemic-epidemic state with 17 cases of TBE-CEE neuro-virus infection, occurring within a short time interval, in a rural community. Recent history revealed tick infestation from a common natural area; the size and dynamics of territorial changes in natural foci by comparing the prevalence of historic TBE-CEE infections in 41 subjects at known occupational risk, 95 subjects from the domestic habitat of former patients with TBE-CEE neuro-infection, and 172 subjects from areas adjacent to natural foci.
Results: Specific serology was positive in 41.5%, 11.6%, and 5.8% of the investigated subjects (chi2 = 38.98); the prevalence of historic TBE-CEE infection in the general population was estimated at 0.6% (0.3-1.1%, CI = 95%) by the seroepidemiological investigation of a representative sample of the Transylvanian population (1669 subjects); the TBE-CEE etiology of acute viral meningitis/meningoencephalitis in the interval 2001-2006 (862 cases in the area) with a prevalence of 14.1% (10.9-17.8%, CI = 95%) of the cases, evaluated based on the etiological investigation of representative samples from 2 counties and on request from the territory (in total 397 investigated cases). Seroepidemiological tests validated by external quality control were performed using the ELISA technique, with standardized immune reagents (IgM and/or IgG specific).
Conclusion: Based on the epidemiological survey performed, it may be concluded that the specific infection sources and the morbidity of human TBE-CEE virus neuro-infections have an endemic emergent course and natural foci are in full territorial expansion.