Investigating the Presence of SARS CoV-2 in Free-Living and Captive Animals.

Lorena Jemeršić1 Ivana Lojkić1 Nina Krešić1 Tomislav Keros1 Tajana Amšel Zelenika2 Luka Jurinović2 Damir Skok3 Ingeborg Bata3 Jadranko Boras3 Boris Habrun1 Dragan Brnić1
Affiliations 3 institutions
  1. Virology Department, Croatian Veterinary Institute, Savska Cesta 143, 10000 Zagreb, Croatia.
  2. Poultry Center, Croatian Veterinary Institute, Heinzelova 55, 10000 Zagreb, Croatia.
  3. Zagreb Zoo, Maksimirski Perivoj, 10000 Zagreb, Croatia.

Abstract

Due to SARS CoV-2 recombination rates, number of infected people and recent reports of environmental contamination, the possibility of SARS CoV-2 transmission to animals can be expected. We tested samples of dominant free-living and captive wildlife species in Croatia for the presence of anti-SARS CoV-2 antibodies and viral RNA. In total, from June 2020 until February 2021, we tested blood, muscle extract and fecal samples of 422 free-living wild boars (Sus scrofa), red foxes (Vulpes vulpes) and jackals (Canis aureus); blood and cloacal swabs of 111 yellow-legged gulls (Larus michahellis) and fecal samples of 32 zoo animals. A commercially available ELISA (ID.Vet, France) and as a confirmatory test, a surrogate virus neutralization test (sVNT; GenScript, Netherlands) were used. Fecal samples were tested for the presence of viral RNA by a real-time RT-PCR protocol. Fifteen out of 533 (2.8%) positive ELISA results were detected; in wild boars (3.9%), red foxes (2.9%) and jackals (4.6%). However, the positive findings were not confirmed by sVNT. No viral RNA was found. In conclusion, no spillover occurred within the investigated period (second COVID-19 wave). However, further investigation is needed, especially regarding wildlife sample features for serological tests.

Supporting text Virus Host Location
free-living wild animals 1 RNA detection 1 SARS CoV-2 2 serology 50 zoo animals 5

Evidence records

2 total
Zoonotic Surveillance
2 records · 2 evidence types
Evidence type
1 records
OVE4818
Key finding

No SARS CoV-2 RNA was detected by real-time RT-PCR in fecal samples collected from free-living and captive animals in Croatia.

Virus
Host
Location
Supporting text

We tested samples of dominant free-living and captive wildlife species in Croatia for the presence of anti-SARS CoV-2 antibodies and viral RNA. Fecal samples were tested for the presence of viral RNA by a real-time RT-PCR protocol. No viral RNA was found.

Method
real-time RT-PCR
Sample type
fecal samples
Geographic raw
Croatia
Country inferred
HRV
Evidence type
1 records
OVE4817
Key finding

Anti‑SARS‑CoV‑2 antibodies were tested in wild boars, red foxes, and jackals in Croatia, showing a few ELISA positives that were not confirmed by sVNT.

Virus
Host
Location
Not specified
Supporting text

We tested samples of dominant free-living and captive wildlife species in Croatia for the presence of anti-SARS CoV-2 antibodies and viral RNA. Fifteen out of 533 (2.8%) positive ELISA results were detected; in wild boars (3.9%), red foxes (2.9%) and jackals (4.6%). However, the positive findings were not confirmed by sVNT.

Method
ELISA | sVNT (surrogate virus neutralization test)
Sample type
blood | muscle extract