Presence of antibodies against H5, H7 and H9 influenza A virus in wild birds in the State of São Paulo, Brazil

Abstract

Although the natural reservoirs of the avian influenza (AI) virus have been extensively studied in many countries, there is a clear lack of information on this subject in South America, particularly in Brazil. The objective of this study was to conduct a serological survey for H5, H7 and H9 antibodies to AI-subtype viruses in wild birds in the state of São Paulo , Brazil. Serum samples were tested using the hemagglutinationinhibition assay. Out of the 31 wild birds sampled between January and December of 2006, seven (22.58%), were seropositive for H5, H7 and H9; four (12.90%) were seropositive for H5 and H7; 13 (41.94%), were seropositive only for H7; three (9.7%), were seropositive only for H9; and four (12.90%) were negative for all three hemagglutinin subtypes. These results indicate that AI viruses belonging to H5, H7 and H9 subtypes circulate among wild birds in the state of São Paulo in the form of either concurrent or consecutive infections. This study contributes to the knowledge of AI epidemiology in Brazil, and stresses the need of further detailed and long-term epidemiological and ecological investigation to determine the current status of this virus.

Avian influenza in Latin America: A systematic review of serological and molecular studies from 2000-2015

“…Moreover, broilers [ 46 ], laying hens [ 47 ], and, to a lesser extent, domestic ducks [ 48 ], quail [ 48 ], and commercial turkeys [ 45 ] were the poultry reported to be affected by avian influenza. In terms of local wild birds, studies mainly include families belonging to the same orders Anseriformes (mainly ducks) and Charadriformes (mainly represented by seagulls), but there are also reports of avian influenza in pelicans, toucans, owls, and doves, among others [ 43 , 44 , 49 – 51 ].…”

“…Studies analysing samples from clinically ill animals that participated in diagnostic programmes in Brazil (27 to 87%) [ 43 , 51 ], Chile (62%) [ 45 ], and Argentina (34.5%) [ 50 ] showed the highest percentage of positive samples. The percentage of positive samples recovered during routine surveillance programmes suggested low infection rates, ranging from 0.07% to 0.62% in Argentina [ 52 – 54 ]; 1.19% in Barbados [ 55 ]; 0.71% in Brazil [ 56 ]; 3.6% in Mexico [ 41 ]; and between 0.22% and 0.88% in Peru [ 44 , 57 ].…”

“…Although two serological studies reported the presence of only H3 AIVs since the late 90s in Brazil,[ 43 ] a diversification of anti-AIV antibodies was reported by 2006 and exposure to H5, H7, and H9 subtypes of AIVs in multiple wild bird species was demonstrated ( Table 1 ) [ 51 ]. Additionally, a molecular characterization study of AIVs in Brazil reported the presence of the LPAI virus subtype H11N9 in Ruddy turnstone ( Arenaria interpres ).…”

<b>Vírus da influenza aviária:</b> monitoramento em aves de subsistência criadas no entorno de sítios de aves migratórias no Brasil

“…Apesar de não terem sido detectadas aves domésticas positivas para os subtipos H5 e H7 do AIV neste trabalho, anticorpos para estes dois subtipos e também para H9 foram detectados em aves silvestres no estado de SP por Sousa et al (2013). Das 31 aves testadas, 27 apresentaram anticorpos para um ou mais subtipos.…”

“…Ainda que as informações sobre possibilidade de coinfecção por diferentes subtipos de AIV em aves domésticas sejam escassas, relatos já foram feitos em aves selvagens. Anticorpos para os subtipos H5, H7 e H9 do AIV foram detectados simultaneamente em aves silvestres de diferentes espécies no Brasil (SOUSA et al, 2013) e em garças na China (WANG et al, 2014b contribuindo para a fixação do homem à terra, para a melhoria da qualidade da dieta e para a complementação da renda de muitas famílias. Sendo assim, espera-se que estes resultados sensibilizem o SVO brasileiro sobre o papel das aves de subsistência como sentinelas para a introdução da influenza aviária no país e sobre a necessidade de ampliação das atividades de vigilância para influenza aviária nesta população a fim de salvaguardar a saúde humana e animal.…”