Serosurveillance for pandemic influenza A (H1N1) 2009 virus infection in domestic elephants, Thailand

• Published in: PloS one Vol. 12; no. 10; p. e0186962
• Main Authors: Paungpin, Weena, Wiriyarat, Witthawat, Chaichoun, Kridsada, Tiyanun, Ekasit, Sangkachai, Nareerat, Changsom, Don, Poltep, Kanaporn, Ratanakorn, Parntep, Puthavathana, Pilaipan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26.10.2017; Public Library of Science (PLoS)
• Subjects: Animals; Animals, Domestic; Antibodies, Viral - blood; Assaying; Biology and Life Sciences; Diagnosis; Diseases and pests; Distribution; Elephants; Enzymes; Health aspects; Hemagglutination; Hemagglutinins; Immunoglobulins; Infections; Influenza; Influenza A; Influenza A Virus, H1N1 Subtype - immunology; Influenza A Virus, H1N1 Subtype - isolation & purification; Medical technology; Medicine and Health Sciences; Orthomyxoviridae Infections - epidemiology; Orthomyxoviridae Infections - veterinary; Orthomyxoviridae Infections - virology; Pandemics; Proteins; Research and Analysis Methods; Risk factors; Surveillance; Swine flu; Thailand; Tourists; Toxoplasma gondii; Vaccines; Virology; Viruses; Zoonoses; Thailand; Bangkok Thailand
• DOI: 10.1371/journal.pone.0186962
• ISSN: 1932-6203

The present study conducted serosurveillance for the presence of antibody to pandemic influenza A (H1N1) 2009 virus (H1N1pdm virus) in archival serum samples collected between 2009 and 2013 from 317 domestic elephants living in 19 provinces situated in various parts of Thailand. To obtain the most accurate data, hemagglutination-inhibition (HI) assay was employed as the screening test; and sera with HI antibody titers ≥20 were further confirmed by other methods, including cytopathic effect/hemagglutination based-microneutralization (microNT) and Western blot (WB) assays using H1N1pdm matrix 1 (M1) or hemagglutinin (HA) recombinant protein as the test antigen. Conclusively, the appropriate assays using HI in conjunction with WB assays for HA antibody revealed an overall seropositive rate of 8.5% (27 of 317). The prevalence of antibody to H1N1pdm virus was 2% (4/172) in 2009, 32% (17/53) in 2010, 9% (2/22) in 2011, 12% (1/8) in 2012, and 5% (3/62) in 2013. Notably, these positive serum samples were collected from elephants living in 7 tourist provinces of Thailand. The highest seropositive rate was obtained from elephants in Phuket, a popular tourist beach city. Young elephants had higher seropositive rate than older elephants. The source of H1N1pdm viral infection in these elephants was not explored, but most likely came from close contact with the infected mahouts or from the infected tourists who engaged in activities such as elephant riding and feeding. Nevertheless, it could not be excluded that elephant-to-elephant transmission did occur.