Ovce kao sentinel životinje za bolest Zapadnog Nila

master's thesis

• Title (english): Sheep as sentinel animal for West Nile disease
• Author: Viktor Mašović
• Mentor: Ljubo Barbić (mentor)
• Mentor: Maja Maurić Maljković (mentor)
• Committee member: Vilim Starešina (predsjednik povjerenstva)
• Committee member: Nevenka Rudan (član povjerenstva)
• Committee member: Maja Maurić Maljković (član povjerenstva)
• Committee member: Ljubo Barbić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Veterinary Medicine; Zagreb
• Defense date and country: 2023-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Veterinary Medicine; Veterinary Public Health and Food Safety

Abstract

Virus Zapadnog Nila (WNV) je emergentni zoonotski uzročnik koji na području
RH posljednjih desetak godina uzrokuje oboljenja ljudi od kojih su neka i sa smrtnim
ishodom. Zbog toga se kontinuirano provodi sustav nadzora virusne aktivnosti
korištenjem konja i peradi kao sentinel životinja. Kako bi istražili mogućnost
unaprjeđenja sustava nadzora, u ovom radu smo istražili mogućnost korištenja ovaca
kao sentinel životinja. U tu svrhu 300 seruma ovaca s područja Vukovarsko-rijemske
županije pretražili smo imunoenzimnim testom (ELISA) te sve s pozitivnim ili
sumnjivim rezultatom dodatno potvrdnim virus neutralizacijskim testom (VN-testom)
uz korištenje tri flavivirusa koja cirkuliraju na području RH. Rezultati su pokazali da je
ELISA test nedostatno specifičan za rutinsku dijagnostiku, a VN-testom su potvrđene
infekcije ovaca WNV, virusom krpeljnog encefalitisa (TBEV) i po prvi put uopće
infekcije ovaca usutu virusom (USUV). Potvrđena je kocirkulacija sva tri virusa na
istom prostoru uz najvišu seroprevalenciju infekcija TBEV koja je sveukupno iznosila
9,7 % uz razlike po lokacijama od 5,0 % do 15,0 %. Ovaj rezultat dodatno zabrinjava
jer ovce mogu TBEV izlučivati mlijekom zbog kojega može doći do oboljenja ljudi.
Seroprevalencija WNV je 3,0%, a najniža seroprevalencije je bila USUV (1,3 %). Uz to
potvrđene su i križne reakcije ili moguće istovremene infekcije različitim flavivirusima
u 1,3 % životinja. Analizirani su i čimbenici rizika te je dokazano da je udaljenost mjesta
držanja ovaca od kućanstva proporcionalna povećanju vjerojatnosti od infekcije TBEV.
Sveukupno istraživanjem je potvrđeno da ovce mogu biti sentinel životinje za
flavivirusne infekcije te da se pretraživanjem ovaca VN-testom kao metodom izbora,
može nadzirati prisustvo i aktivnost WNV, TBEV, ali i USUV što je dokazano po prvi
put.

Abstract (english)

In the last decade, the West Nile virus (WNV) is an emerging zoonotic disease in
Croatia, causing illness and fatalities in people. The surveillance of viral activity is
continuously implemented using horses and poultry as sentinel animals. This study
aimed to investigate sheep as the possible sentinel animals in the surveillance program
of WNV. The study was conducted on sheep sera from Vukovarsko-srijemska County
in May 2022. In total, 300 sheep sera were tested using the ELISA test. Additionally, all
positive and suspicious ELISA results were examined with VN-test using all three
flaviviruses circulating in Croatia. The results revealed that ELISA is insufficiently
specific for routine diagnostics. On the other hand, VN-test confirmed cases of WNV,
TBEV and, for the first time, USUV infection in sheep. TBEV had the highest
seroprevalence (9.7 %), ranging from 5.0 % - 15.0 % between locations. This result is
concerning because TBEV can be found in sheep milk, which can be a source of human
infection. WNV seroprevalence was 3.0 %, and USUV had the lowest seroprevalence
(1.3 %). In addition, cross-reactions or possible simultaneous infections with different
flaviviruses were confirmed in 1.3 % of animals. Risk factors analysis revealed that the
distance of sheep habitat from houses is proportional to the probability of infection with
TBEV. Overall, this research confirmed that sheep could be used as sentinel animals in
flavivirus surveillance programs. They could detect the presence and activity of WNV,
TBEV, and USUV with a VN-test as a diagnostic method of choice.

• Keywords: WNV; TBEV; USUV; sentinel životinje; ovce
• Keywords (english): NV; TBEV; USUV; sentinel; sheep
• Language: croatian
• URN:NBN: urn:nbn:hr:178:809202
• Study programme: Title: Veterinary Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica veterinarske medicine (doktor/doktorica veterinarske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-09-12 11:28:50