Epidemiological surveillance of avian influenza viruses in migratory birds on the Amazon coast

Author(s)

Renata Ferreira Hurtado

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2014-02-04

Examining board members

José Antonio Jerez; Edison Luiz Durigon; José Henrique de Hildebrand e Grisi Filho; Marta Brito Guimarães; Cristiane Kiyomi Miyaji Kolesnikovas

• Advisor: José Antonio Jerez

Abstract

Avian influenza viruses infect a variety of birds and mammals and are known for their relevant enconomic and public health impacts. Anseriformes (ducks, mallards and geese) and Charadriiformes (shorebirds, seagulls and terns) are natural reservoirs of avian influenza viruses, and the migratory behaviour of many of these species can result in the spread of the virus among countries. There are few studies investigating the occorrence of these viruses in South America, hindering understanding of their ecology and epidemiology in Brazil. This study aims to detect and characterize avian influenza viruses in migratory birds in wintering areas on the Amazon coast. Orotracheal and cloacal swabs were obtained from 1093 wild birds, mostly Anseriformes and Charadriiformes, during six expeditions between 2008 and 2010 to the state of Pará, Brazil. Samples from nine birds were positive to Real time RT-PCR: 2 Actitis macularius, 4 Arenaria interpres, 1 Calidris pusilla, 1 Charadrius semipalmatus e 1 Dendrocygna viduata. Virus isolation was successfully carried out for the samples from three Arenaria interpres, in agreement with previous studies reporting high prevalence in this species. Hemaglutinin and neuraminidase inhibition assays indicated these strains belonged to subtype H11N9, considered low pathogenic and relatively common in shorebirds. Gene sequencing demonstrated close phylogenetic relationship between the strains isolated in this study and those found in North America, revealing the existence of epidemiological conectivity among these populations. It is therefore vital to maintain active epidemilogical surveillance of wild birds in this region, collecting information on virus prevalence, subtype and pathogenicity that may in turn be used to implement prevention and control policies for avian influenza outbreaks. (AU)

• FAPESP's process: 09/10695-0 - Epidemiological surveillance of Influenza A viruses in migratory birds on the Amazon coast
• Grantee: Renata Ferreira Hurtado
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)