Epidemic breakdown of viral meningitis in Split Dalmatia County

Abstract

Cilj istraživanja: Retrospektivnom studijom epidemija virusnih meningitisa u Splitsko-dalmatinskoj županiji (SDŽ) u razdoblju od 2003. do 2015. godine utvrditi razlike pojavnosti virusnog meninigitisa. Ispitanici i metode: Istraživanje je provedeno kod stanovnika petnaest epidemioloških područja i sa dvanaest sustava javne vodoopskrbe (VOS) na tri zemljopisno, kulturalno i gospodarski različita područja SDŽ: priobalje, otoci i zagora. U radu je korišten komparativni epidemiološki metod temeljem broja hospitalizacija MV u Kliničkom bolničkom centru Split. Stope hospitalizacija izračunate su za stanovnike svih dobi, dobi do 19 godina i dobi 20-64. Prikazane su u stopama na 100.000 stanovnika, a statistička značajnost izračunata je χ²-testom i Studentovim t-testom. Značajnost razlika iskazana je na stupnju pouzdanosti <0,05; <0,01 i <0,001. Rezultati: U razdoblju 2003.-2015. godine hospitalizirano je 509 bolesnika, standardizirana prosječna godišnja stopa 8,19/100.000 (95% CI 4,12-12,25) uz trend porasta broja bolesnika. Muški spol je prevladavao 328 (64,4%) ili 1,8 : 1. U dobi do 19 godina bilo je 356 hospitalizacija (69,9%), dobno specifična stopa 24,74/100.000 (95% CI 10,53-38,95). Najviše bolesnika bilo je u dobnom razredu 5-9 godina 173 bolesnika (34,0% svih dobi). Stanovnici svih dobi priobalja SDŽ imali su najveće stope hospitalizacija 8,89/100.000 (95% CI 3,78-14,00), zatim stanovnici otoka SDŽ 6,49/100.000 (95% CI 2,59-10,39) te stanovnici zagore SDŽ 6,35/100.000 (95% CI 3,69-9,01). U dobi do 19 godina: priobalje 27,23/100.000 (95% CI 9,58-45,81), otoci 22,25 (95% CI 6,17-38,33), zagora 17,37 (95% CI 7,98-26,75). Suprotno očekivanju stanovnici općina imaju manje stope hospitalizacija od stanovnika gradova kako za stanovnike svih dobi 7,77/100.000 vs. 8,82/100.000 tako i za dob do 19 godina 23,82/100.000 vs. 26,57/100.000. Epidemije 2006.-2007. i 2013.-2014. imaju tipičnu sezonsku raspodjelu s vrhuncima u toplijem ljetnom razdoblju. Stanovnici svih dobi priobalja SDŽ imali su statistički značajno veću stopu hospitalizacija 16,95/100.000 od stanovnika zagore SDŽ 13,57/100.000 (χ²=15,40; p<0,001), kao i u dobi do 19 godina 56,68/100.000 vs. 43,89/100.000 (χ²=12,40; p<0,001). Po epidemiološkim područjima statistički značajno veće stope hospitalizacija bile su kod stanovnika Ispostave Split i statistički značajno najmanje kod stanovnika Makarskog primorja i na otocima kod kojih gotovo nije bilo epidemijske pojavnosti. Prema raspodjeli bolesnika po sustavima javne vodoopskrbe stanovnici RS Makarsko primorje i RS Omiš-Brač-Hvar-Šolta, koji raspolažu uređajima za kondicioniranje i popravku voda (UKPV), u odnosu na ostale koji nemaju UKPV, imaju statistički značajno manji rizik infekcija kako u izvanepidemijskim godinama 6,37/100.000 vs. 9,23/100.000 (χ²=7,13; p<0,01) tako i u epidemijskim godinama 9,87/100.000 vs. 19,04/100.000 (χ²=11,31; p<0,001). Mali broj urađenih viroloških izolata ukazuje da je epidemija 2006.-2007. godine imala politipiju enterovirusa (Echovirus 6, 11 i 30, Coxackievirus B5) dok je u epidemiji 2013.-2014. izoliran samo Echovirus 30. Zaključak: trend porasta hospitalizacija zbog MV stanovnika u razdoblju 2003.-2015. godine posljedica je povećanog unosa novih tipova uzročnika MV poglavito virusa iz roda enterovirusa. Zbog nedostatne virološke kliničke i sanitarne dijagnostike može se samo neizravno procijeniti da je prevladavajući mehanizam prijenosa virusa vodom za ljudsku potrošnju i rekreacijskim vodama. Potvrda tome su statistički značajno manje stope hospitalizacija s područja RSS vodoopskrbe koji raspolažu UKPV kao i kanalizacijom poboljšano uklanjanje ljudskih izlučevina.Research Goals: The goal of this thesis was to examine and explore the differences in the epidemic outbreak of viral meningitis in geographically and economically different areas of Split-Dalmatia County , on the coast, hinterlands and the islands from 2003 until 2015. Methods: A comparative epidemiological method was used in this paper based on the number of MV hospitalizations in Split Clinical Hospital Center. Hospitalization rates are calculated for residents of all ages, up to the age of 19 and age 20-64. They are presented in rates per 100,000 inhabitants, and statistical significance is calculated by χ²-test and Student's t-test. The significance of the difference is expressed in the degree of reliability <0.05; <0.01 and <0.001. Resaults: During the examined period between 2003 and 2015 , 509 patients have been hospitalized with a standard yearly rate of 8,19/100 000 (95% CI 4,12-12,25). Males were more effected with 328 patients (64,4%) or 1,8:1. In the 0 to 19 age range there were 356 cases of hospitalization (69,9%), with the age-specific rate 24,74/100 000 (95% CI 10,53-38,95). Most patients belonged to the 5-9 age group, 173 patients (34,0% of all ages). Residents of all ages in the coastal part of Split-Dalmatia County had the largest hospitalization rate 8,89/100 000 (95% CI 3,78-14,00), followed by the island residents 6,49/100.000 (95% CI 2,59-10,39) and the hinterlands residents of Split-Dalmatia County 6,35/100.000 (95% CI 3,69-9,01), with no statistical significance. In the 0 to 19 age range there are no statistical significances between the regions of Split-Dalmatian County as well: coastal part 27,23/100.000 (95% CI 9,58-45,81), islands 22,25 (95% CI 6,17-38,33), hinterlands 17,37 (95% CI 7,98-26,75). Contrary to expectations, municipal residents have lower hospitalization rates than city residents both for groups of all ages 7,77/100.000 vs. 8,82/100.000 as well as the 0-19 age range 23,82/100.000 vs. 26,57/100.000. Epidemics in the period between 2006-2007. and 2013-2014. had a typical seasonal distribution, peaking in the warmer, summer months of the year. The County's coastal residents had a statistically significant larger hospitalization rate 16,95/100 000 than those residing in the hinterlands 13,57/100 000 (χ²=15,40; p<0,001). In the 0-19 age range that difference is statistically significant as well 56,68/100.000 vs. 43,89/100.000 (χ²=12,40; p<0,001). The rate of hospitalizations according to water supply systems show statistically significant differences. The residents of the Makarska Riviera, Omiš-Brač-Hvar-Šolta regions and Sinj water supply system have statistically significant lower hospitalization rates for the 2003-2015 period as a whole as well as for the epidemic years, both for all age groups and for 0-19 age range as well. The statistically largest hospitalization rates are in Solin-Split-Kaštela-Trogir region. It is important to note that Makarska Riviera and Omiš-Brač-Hvar-Šolta regions, who have water intakes form the surface waters of Cetina river, are the only ones who have water conditioning and purification systems. In other words, total hygienic water processing with chlorination at the end as a disinfection measure, while other water supply systems have only chlorination without hygienic water processing. The virological laboratory confirmation of the diagnosis has been given to a minor number of patients. However, a small number of isolates shows that the 2006-2007 outbreak had a polytypic enterovirus (Echovirus 6, 11 i 30, Coxackievirus B5) as the cause, while in the 2013-2014 outbreak only the Echovirus 30 was isolated. Conclusion: From the results of this research it can be concluded that the rising trend of hospitalization of residents of Split-Dalmatian County due to viral meningitis during 2003-2015 is a consequence of growing tourist migrations and increased intake of new causes of viral meningitis, primarily of the enterovirus strain. Due to insufficient virological clinical diagnostics and sanitary-virological tests, it is only indirectly through epidemiologic breakdown that it can be concluded that the prevailing method of transmission is through water for human consumption as well as recreational waters. Evidence of that can be seen in statistically significant lower hospitalization rates in water supply areas with water conditioning and purification systems, in other words, total hygienic processing of water for human consumption as well as a improved method of disposing human waste