Iva Pem-Novosel, Tatjana Vilibić-Čavlek
Hrvatski zavod za javno zdravstvo, Zagreb
E-mail: tatjana.vilibic-cavlek@hzjz.hr
Iva Pem-Novosel (Croatian National Institute of Public Health, Zagreb, Croatia)
U radu prikazujemo prve slučajeve neuroinvazivne bolesti uzrokovane West Nile virusom (WNV) kod ljudi u Hrvatskoj.
WNV je prvi put opisan 1937. god. na području Zapadnog Nila u Ugandi. Tijekom dva posljednja desetljeća, u svijetu je zabilježeno više epidemija WNV. Uz SAD, velike su epidemije opisane u Europi i na području Mediterana. U zadnjih nekoliko godina WNV neuroinvazivne infekcije su bilježene u Italiji (2008-2010. god.), Rumunjskoj (2010-2012. god.) i Grčkoj (2010-2012. god.). U srpnju 2012. god. prvi put je registrirana epidemija WNV infekcije u Srbiji s 44 laboratorijski potvrđena slučaja. Životna dob oboljelih je 17-82 god. Do sada je od WNV infekcije u Srbiji umrlo šestero ljudi, a u Makedoniji i Kosovu po jedna osoba.
Od 1970. do 1988. god. u Hrvatskoj je provedeno nekoliko seroepidemioloških studija o prisutnosti WNV koje su pokazale prevalenciju od 0,28% do 4,9%. U pilot istraživanju provedenom 2011. god. u skupini od 360 slučajno odabranih zdravih ispitanika u dobi od 30-60 god., WNV IgG protutijela su dokazana u samo jednog ispitanika s područja istočne Hrvatske (0,3%).
U rujnu 2012. god. zabilježeni su prvi slučajevi neuroinvazivne WNV bolesti u ljudi u Hrvatskoj koja je do sada dokazana u šest bolesnika. U prvog su se bolesnika simptomi pojavili 04. kolovoza, a u posljednjeg 07. rujna 2012. Četiri su bolesnika imala kliničku sliku meningoencefalitisa te dva bolesnika sliku encefalitisa. Medijan dobi iznosio je 62 god. (raspon 48-77 god.). U prvom se slučaju radilo o importiranoj WNV infekciji iz Srbije (oboljeli je boravio u selu Ratkovo u Srbiji od 24.-31. srpnja, tijekom razdoblja inkubacije), dok su ostali slučajevi autohtono stečeni. Petero bolesnika se potpuno oporavilo.
Serološko testiranje je učinjeno u Nacionalnom referentnom laboratoriju za arboviruse i rikecije pri Hrvatskom zavodu za javno zdravstvo. WNV IgM i IgG protutijela dokazana su pomoću komercijalnog ELISA testa (Euroimmun, Lübeck, Germany). Serumi su također testirani na druge flaviviruse (virus krpeljnog encefalitisa i virus dengue) zbog mogućih križnih reakcija. Četiri su uzorka potvrđena u OIE Referentnom laboratoriju za WNV, Istituto G. Caporale, Teramo, Italija neutralizacijskim testom redukcije plakova (PRNT) i mikroneutralizacijskim testom (NT). Real-time RT-PCR (WNV linija 1 i 2) je bio negativan u svim testiranim uzorcima. Rezultati seroloških pretraga prikazani su u tablici.
Bolesnici s dokazanom neuroinvazivnom WNV bolesti su s područja tri županije istočne Hrvatske koje se nalaze uz granicu sa Srbijom (Brodsko-posavska, Osječko-baranjska i Vukovarsko-srijemska županija).
U svrhu suzbijanja komaraca, odmah su provedeni adulticidni i larvicidni tretmani kao učinkovite protuepidemijske mjere na područjima gdje su otkrivene oboljele osobe.Tablica. Serološki rezultati šest bolesnika s neuroinvazivnom WNV infekcijom u Hrvatskoj, 2012.
Slučaj Dob Mjesto boravka Klinička dijagnoza WNV ELISA
IgM/IgGPRNT* NT* 1 65 Nova Gradiška Meningoencefalitis Poz / Poz 20 20 2 77 Vukovar Meningoencefalitis Poz / Poz 10 10 3 48 Budimci Encefalitis Poz / Poz 10 20 4 76 Belišće Meningoencefalitis Poz / Neg 5 10 5 60 Slavonski Brod Meningoencefalitis Poz / Poz – – 6 48 Osijek Encefalitis Poz / Poz – –
First outbreak of West Nile virus neuroinvasive infection in humans in Croatia
Iva Pem-Novosel, Tatjana Vilibić-Čavlek
Croatian National Institute of Public Health, Zagreb
E-mail: tatjana.vilibic-cavlek@hzjz.hrWe are reporting the first outbreak of West Nile virus (WNV) neuroinvasive infection in humans in Croatia.
WNV was originally identified in 1937 in West Nile District of Uganda. During the last two decades, several WNV outbreaks have occurred throughout the world. In addition to USA, large outbreaks of WNV have been reported in Europe and in the Mediterranean basin. In the past few years, WNV neuroinvasive disease was notified in Italy (2008-2012), Romania (2010-2012) and Greece (2010-2012). In July 2012 first outbreak of WNV disease has occurred in Serbia with 44 laboratory diagnosed cases aged 17-82 years and six deaths up to now. In Macedonia as well as in Kosovo one death of West Nile virus was reported.
In Croatia, several seroepidemiological studies on WNV in humans have been conducted during 1970-1998 which have shown the prevalences ranging from 0.28% to 4.9%. In 2011, a pilot seroprevalence study has been performed in a group of 306 randomly selected healthy adult people aged 30-60 years. Only one participant (0.3%) from eastern Croatia showed positive WNV IgG antibodies.
In September 2012, first outbreak of WNV neuroinvasive infection in humans in Croatia was reported. Six patients with WNV disease were detected up to now. The first WNV case had symptoms onset on 04 August and the last on 07 September. Four patients presented with clinical symptoms of meningoencephalitis and two patients with encephalitis. The median patient age was 62 years (range 48-77 years). The first case was imported from Serbia (patient resided in Ratkovo village in Serbia from 24-31 July, during the incubation period) while the others represent first autochthonous WNV cases. All but one patient were recovered.
WNV IgM and IgG testing was performed at the National Reference Laboratory for Arboviruses at Croatian National Institute of Public Health using commercial ELISA (Euroimmun, Lübeck, Germany). Sera were also tested for the presence of other flaviviruses (tick-borne encephalitis virus and dengue virus) to rule out cross-reactions. Four samples were confirmed at the OIE Reference Laboratory for West Nile Disease, Istituto G. Caporale, Teramo, Italy by plaque-reduction neutralization assay (PRNT) and micro-neutralization assay (NT). Real-time RT-PCR (lineage 1 and 2) was negative in all tested samples. Laboratory test results of six patients with WNV neuroinvasive infection are presented in the Table.
Patients with WNV disease are residents of three counties (Brod-Posavina County, Osijek-Baranja County and Vukovar-Srijem County) located in eastern Croatia, near the Serbian state border. Adulticide and larvicidal treatment as effective epidemic control measures were implemented immediately in patient’s places of residence in Osijek-Baranja County and Vukovar-Srijem County.Table. Serological results of six patients with neuroinvasive WNV infection in Croatia, 2012
Case Age Place of residence Clinical Diagnosis WNV ELISA
IgM/IgGPRNT* NT* 1 65 Nova Gradiška Meningoencefalitis Pos / Pos 20 20 2 77 Vukovar Meningoencefalitis Pos / Pos 10 10 3 48 Budimci Encefalitis Pos / Pos 10 20 4 76 Belišće Meningoencefalitis Pos / Neg 5 10 5 60 Slavonski Brod Meningoencefalitis Pos / Pos – – 6 48 Osijek Encefalitis Pos / Pos – –