Surveillance of Influenza Viruses in Waterfowl Used As Decoys in Andalusia, Spain

Abstract

A longitudinal study was carried out to determine the seroprevalence of avian influenza viruses (AIVs) in waterfowl used as decoys in Andalusia, southern Spain. A total of 2319 aquatic birds from 193 flocks were analyzed before and after the hunting season 2011–2012. In the first sampling, 403 out of 2319 (18.0%, CI95%: 15.8–19.0) decoys showed antibodies against AIVs by ELISA. The AI seroprevalence was significantly higher in geese (21.0%) than in ducks (11.7%) (P<0.001). Besides, the spatial distribution of AIVs was not homogeneous as significant differences among regions were observed. The prevalence of antibodies against AIVs subtypes H5 and H7 were 1.1% and 0.3%, respectively, using hemagglutination inhibition test (HI). The overall and H5 seroprevalences slightly increased after the hunting period (to 19.2% and 1.4%, respectively), while the H7 seroprevalence remained at the same level (0.3%). The proportion of flocks infected by AIVs was 65.3%, while 11.2% and 4.9% of flocks were positive for H5 and H7, respectively. Viral shedding was not detected in any of the 47 samples positive by both ELISA and HI, tested by RRT-PCR. The individual incidence after the hunting season was 3.4%. The fact that 57 animals seroconverted, 15 of which were confirmed by HI (12 H5 and 3 H7), was indication of contact with AIVs during the hunting period. The results indicate that waterfowl used as decoys are frequently exposed to AIVs and may be potentially useful as sentinels for AIVs monitoring. The seroprevalence detected and the seropositivity against AIVs H5 and H7, suggest that decoys can act as reservoirs of AIVs, which may be of animal and public health concern.

Influenza A Virus Surveillance in the Invasive American Mink (Neovison vison) from Freshwater Ecosystems, Northern Spain

“…Influenza subtypes other than reported previously may have been circulating in the American mink populations from Northern Spain. In this sense, the few studies performed in order to describe the circulating AIV in wild birds from Spain reported a wide variety of low‐pathogenic AIVs and a wide range of prevalence of infection (Barral et al., ; Busquets et al., ; Pérez‐Ramírez et al., ; Jurado‐Tarifa et al., ; ).…”

“…Influenza subtypes other than reported previously may have been circulating in the American mink populations from Northern Spain. In this sense, the few studies performed in order to describe the circulating AIV in wild birds from Spain reported a wide variety of low-pathogenic AIVs and a wide range of prevalence of infection (Barral et al, 2008;Busquets et al, 2010;P erez-Ram ırez et al, 2010;Jurado-Tarifa et al, 2014;). Continued interactions of mammals and birds increase the likelihood of IAV adaptation or reassortment, thereby allowing the emergence of novel influenza viruses in mammalian hosts and perhaps with zoonotic potential (Roberts et al, 2009;Britton et al, 2010;Sponseller et al, 2010).…”

Biosurveillance of avian influenza and Newcastle disease viruses in the Barda region of Azerbaijan using real time RT-PCR and hemagglutination inhibition

“…Another surveillance program aimed at evaluating AIVs in waterfowl in Spain identified 1.1 and 0.3% of birds seropositive for H5 and H7. Of 47 samples that tested positive by both HI and ELISA, all tested negative by rRT-PCR ( Jurado-Tarifa et al, 2014 ). A study using both HI and RT-PCR to investigate ND in caged birds in Tehran, found that RT-PCR was more sensitive for detection of active carriers than was the HI test when 35 of 335 tested positive by RT-PCR but were not positive by HI ( Madadgar et al, 2013 ).…”

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): low pathogenic avian influenza

“…Comparing MS or poultry categories is not possible due to large variations in the number of samples per country and per poultry category. LPAI has been detected in wild birds across the year and in several MS (Barral et al, 2008;Busquets et al, 2010;Perez-Ramirez et al, 2010Jurado-Tarifa et al, 2014;Latorre-Margalef et al, 2014;Swieton et al, 2017). Furthermore, the maps in Figure 1 show that some regions had seropositive holdings in 2014 and 2015.…”

“…LPAI has been detected in wild birds across the year and in several MS (Barral et al., ; Busquets et al., ; Perez‐Ramirez et al., , ; Jurado‐Tarifa et al., ; Latorre‐Margalef et al., ; Swieton et al., ). Furthermore, the maps in Figure show that some regions had seropositive holdings in 2014 and 2015.…”