Dokaz i kvantificiranje ovčjeg herpesvirusa 2 u Hrvatskoj

Abstract

Ovine herpesvirus-2 (OvHV-2), a gammaherpesvirus (genus Rhadinovirus) causes a severe disease known as sheep-associated malignant catarrhal fever (SA-MCF) in certain ruminants, such as cow, deer, bison and water buffalo. Suspected cases of SA-MCF in cows without identififi cation of the agent have been reported in Croatia in the past. In June 2005, on a farm in northwest Croatia, where 17 Simmental diary cows and 2 heifers shared stables and meadows with sheep, a 13 month-old heifer showed symptoms reminiscent of SA-MCF, including anorexia, high fever, nasal discharge, and neurological symptoms, such as ataxia, tremor, convulsions and hyperesthesia. The animal died within 14 days. Gross necropsy fifi ndings were sharply demarcated erosions on mucosal surfaces, including the tongue, oral mucosa, esophagus, abomasum, jejunum, colon, caecum and urinary bladder. Histopathology revealed extremely severe perivascular and intramural arterial infifi ltrations with mononuclear cells, mostly lymphocytes. These lesions were seen in almost every organ, especially the brain and lungs. Formaldehyde fixed samples from the brain, cerebellum, spleen and lymph nodes were obtained and subjected to DNA extraction procedures. Fluorogenic real-time PCR (Polymerase chain reaction) amplififi cation specific to OvHV-2 DNA was performed and OvHV-2 DNA was detected in the brain, cerebellum and spleen, as well as in the lymph nodes. These data indicate that the animal had been infected with OvHV-2, the agent of SA-MCF. For the first time, OvHV-2 was identified and quantified in a Croatian heifer as the causative agent of SA-MCF.Ovčji herpesvirus 2 (OvHV-2) iz roda Rhadinovirus, potporodice Gammaherpesvirinae uzročnik je zarazne korice goveda u nekih vrsta domaćih i divljih preživača. Dosad su u Republici Hrvatskoj zabilježeni mnogi slučajevi sumnje na pojavu zarazne korice u goveda temeljeni na kliničkoj metodi dijagnosticiranja, ali bez dokaza uzročnika bolesti. U lipnju 2005. godine na jednoj farmi u sjeverozapadnoj Hrvatskoj zabilježena je pojava zarazne korice goveda u jedne junice, simentalske pasmine, u dobi od 13 mjeseci, koja je bila smještena u istoj staji s još 17 mliječnih krava i jednom junicom simentalske pasmine te manjim stadom ovaca. Životinja je naglo oboljela uz znakove gubitka apetita, visoke vrućice, seroznog iscjetka iz nosa te pojavom znakova središnjega živčanoga sustava, ataksije, tremora, grčeva i hiperestezije. Životinja je uginula 14. dan od početka prvih znakova bolesti. Razudbom je utvrđena prisutnost oštro ograničenih erozija na sluznici jezika, usne šupljine, jednjaka, sirišta, tankoga, debeloga i slijepoga crijeva te mokraćnoga mjehura. Histopatološki je gotovo u svakom organu, a posebno u mozgu i plućima, utvrđena jaka perivaskularna i intramuralna infiltracija arterija mononuklearnim stanicama, većinom limfocitima. Iz formalinom fiksiranih uzoraka mozga, maloga mozga, slezene i limfnih čvorova izdvojena je DNK i podvrgnuta fluorogenoj real-time PCR amplifikaciji specifičnoj za OvHV-2. OvHV-2 dokazan je i kvantificiran u svim pretraživanim organima. Dobiveni rezultat upućuje na to da je uginula životinja bila zaražena s OvHV-2 što je ujedno i prvi dokaz uzročnika zarazne korice goveda u Hrvatskoj