1
|
Antigenic comparison of H3N8 equine influenza viruses belonging to Florida sublineage clade 1 between vaccine strains and North American strains isolated in 2021-2022. Arch Virol 2023; 168:94. [PMID: 36806782 DOI: 10.1007/s00705-023-05720-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/24/2023] [Indexed: 02/23/2023]
Abstract
Equine influenza virus strains of Florida sublineage clade 1 (Fc1) have been circulating in North America. In this study, virus neutralization assays were performed to evaluate antigenic differences between Fc1 vaccine strains and North American Fc1 strains isolated in 2021-2022, using equine antisera against A/equine/South Africa/4/2003 (a vaccine strain recommended by the World Organisation for Animal Health) and A/equine/Ibaraki/1/2007 (a Japanese vaccine strain). Antibody titers against four North American Fc1 strains isolated in 2021-2022 were comparable to those against the homologous vaccine strains. These results suggest that current Fc1 vaccine strains are effective against North American strains from 2021-2022.
Collapse
|
2
|
Abstract
Influenza is an extremely contagious respiratory disease, which predominantly affects the upper respiratory tract. There are four types of influenza virus, and pigs and chickens are considered two key reservoirs of this virus. Equine influenza (EI) virus was first identified in horses in 1956, in Prague. The influenza A viruses responsible for EI are H7N7 and H3N8. Outbreaks of EI are characterized by their visible and rapid spread, and it has been possible to isolate and characterize H3N8 outbreaks in several countries. The clinical diagnosis of this disease is based on the clinical signs presented by the infected animals, which can be confirmed by performing complementary diagnostic tests. In the diagnosis of EI, in the field, rapid antigen detection tests can be used for a first approach. Treatment is based on the management of the disease and rest for the animal. Regarding the prognosis, it will depend on several factors, such as the animal's vaccination status. One of the important points in this disease is its prevention, which can be done through vaccination. In addition to decreasing the severity of clinical signs and morbidity during outbreaks, vaccination ensures immunity for the animals, reducing the economic impact of this disease.
Collapse
|
3
|
Nemoto M, Ohta M, Yamanaka T, Kambayashi Y, Bannai H, Tsujimura K, Yamayoshi S, Kawaoka Y, Cullinane A. Antigenic differences between equine influenza virus vaccine strains and Florida sublineage clade 1 strains isolated in Europe in 2019. Vet J 2021; 272:105674. [PMID: 33941332 DOI: 10.1016/j.tvjl.2021.105674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 01/10/2023]
Abstract
From late 2018 to 2019, equine influenza virus (EIV) strains of Florida sublineage clade 1 (Fc1), which had until then been circulating mainly in the United States, suddenly spread across Europe causing many outbreaks, and Florida sublineage clade 2 (Fc2) strains, which had been circulating mainly in Europe, have not been detected in Europe since 2018. Since 2010, the World Organisation for Animal Health (OIE) has recommended that EIV vaccines contain an Fc1 strain that is like A/equine/South Africa/4/2003 or A/equine/Ohio/2003. Accordingly, Japanese vaccines contain A/equine/Ibaraki/1/2007 as the Fc1 strain. To evaluate the effectiveness of these vaccines against the Fc1 strains detected in Europe in 2019, we performed virus neutralization tests using horse antisera. Challenge viruses used were Irish strain A/equine/Tipperary/1/2019 and two recombinant viruses generated by reverse genetics. Recombinant viruses possessing hemagglutinin (HA) and neuraminidase (NA) derived from A/equine/Tipperary/1/2019 (rA/equine/Tipperary/1/2019) or British strain A/equine/Essex/1/2019 (rA/equine/Essex/1/2019) were generated. Equine antisera against A/equine/South Africa/2003 and A/equine/Ibaraki/2007 were produced by experimental infection. Antibody titers against A/equine/Tipperary/1/2019, rA/equine/Tipperary/1/2019, and rA/equine/Essex/1/2019 were 2.5- to 6.3-fold lower than those against the homologous vaccine strains A/equine/South Africa/4/2003 or A/equine/Ibaraki/2007. These results suggest that the ongoing evolution of the Fc1 viruses may impact on antigenicity and although antibodies against current vaccine strains neutralize the 2019 strains, ongoing surveillance is essential for optimum choice of candidate vaccine strains.
Collapse
Affiliation(s)
- Manabu Nemoto
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan.
| | - Minoru Ohta
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Takashi Yamanaka
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Yoshinori Kambayashi
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Hiroshi Bannai
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Koji Tsujimura
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Seiya Yamayoshi
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Yoshihiro Kawaoka
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Ann Cullinane
- Virology Unit, Irish Equine Centre, Naas, Co. Kildare, W91 RH93 Johnstown, Ireland
| |
Collapse
|