West Nile, Sindbis and Usutu Viruses: Evidence of Circulation in Mosquitoes and Horses in Tunisia

Youmna M’ghirbi (1, 2) , Laurence Mousson (3) , Sara Moutailler (4) , Sylvie Lecollinet (4) , Rayane Amaral (5) , Cécile Beck (5) , Hajer Aounallah (1, 2) , Meriem Amara (2, 1) , Ahmed Chabchoub (2, 1, 6) , Adel Rhim (2, 1) , Anna-Bella Failloux (3) , Ali Bouattour (1, 2)

1 Institut Pasteur de Tunis
2 UTM - Université de Tunis El Manar
3 Arbovirus et Insectes Vecteurs - Arboviruses and Insect Vectors
4 BIPAR - Biologie moléculaire et immunologie parasitaires et fongiques
5 VIRO - Virologie UMR1161
6 UMA - Université de la Manouba [Tunisie]

Mosquito-borne diseases have a significant impact on humans and animals and this impact is exacerbated by environmental changes. However, in Tunisia, surveillance of the West Nile virus (WNV) is based solely on the surveillance of human neuroinvasive infections and no study has reported mosquito-borne viruses (MBVs), nor has there been any thorough serological investigation of anti-MBV antibodies in horses. This study therefore sought to investigate the presence of MBVs in Tunisia. Among tested mosquito pools, infections by WNV, Usutu virus (USUV), and Sindbis virus (SINV) were identified in Cx. perexiguus. The serosurvey showed that 146 of 369 surveyed horses were positive for flavivirus antibodies using the cELISA test. The microsphere immunoassay (MIA) showed that 74 of 104 flavivirus cELISA-positive horses were positive for WNV, 8 were positive for USUV, 7 were positive for undetermined flaviviruses, and 2 were positive for tick-borne encephalitis virus (TBEV). Virus neutralization tests and MIA results correlated well. This study is the first to report the detection of WNV, USUV and SINV in Cx. perexiguus in Tunisia. Besides, it has shown that there is a significant circulation of WNV and USUV among horses, which is likely to cause future sporadic outbreaks. An integrated arbovirus surveillance system that includes entomological surveillance as an early alert system is of major epidemiological importance.

Domaines: Sciences du Vivant [q-bio]; Médecine vétérinaire et santé animale; Virologie

Youmna M’ghirbi, Laurence Mousson, Sara Moutailler, Sylvie Lecollinet, Rayane Amaral, et al.. West Nile, Sindbis and Usutu Viruses: Evidence of Circulation in Mosquitoes and Horses in Tunisia. Pathogens, 2023, 12 (3), pp.360. ⟨10.3390/pathogens12030360⟩. ⟨anses-04019681⟩