Avian Migration-Mediated Transmission and Recombination Driving the Diversity of Gammacoronaviruses and Deltacoronaviruses.

Consequences of seasonal migration : How goose relocation strategies influence infection prevalence and pathogen dispersal

During extreme months of winter, December and January, every year, the migratory birds from Siberia travel to Indus Valley and other parts of Indo-Pakistan subcontinent. These migratory birds include, ducks, geese, swans and the water fowls. These birds are known to carry all avian influenza viruses and by shedding virus, they are assumed to be vector. Samples were collected from migratory and non migratory wild birds at lakes, zoo and live bird market. Samples were processed in the National Reference Laboratory of Poultry Diseases, National Agricultural Research Council (NARC), Islamabad for virus isolation, HI and reverse transcription-polymerase chain reaction (RT-PCR) for the detection of H3, H5, H7 and H9 serotypes of avian influenza virus type A. It was concluded that migratory birds flying over the Pakistan territorywere negative against H3, H5 and H7. However, positive samples for H9 serotype were found in backyard poultry. Key words: Antibodies, avian influenza, hemagglutination inhibition, migratory birds, RT-PCR, surveillance.

Artificial illumination on offshore oil and gas installations has a variety of effects on migratory and non-migratory birds, especially at night during foggy or overcast conditions. Birds attracted to platform lighting during the autumnal migration can result in encirclement causing elevated avian mortality rates from bird strike, incineration in the flare (when the flare is in operation) and exhaustion. The problem has been documented for many years from areas as diverse as the North Sea, the Gulf of Mexico and Western Australia (Wiese et al., 2001). The impact of artificial light sources at night on migratory birds is a phenomenon not just linked to oil and gas platforms but also to other illuminated offshore and coastal structures such as wind farms, ships, harbors and lighthouses, all of which contribute to light pollution at night. Following several years of detailed observations, the Dutch E&P company NAM (Nederlandse Aardolie Maatschappij), established that conventional lights on offshore installations were the critical factor in luring migratory birds to offshore installations and keeping them trapped flying in circles for prolonged periods of time, particularly during so-called ‘broad front’ migration in combination with fog or cloudy weather when all the platforms in the same region experience the encirclement phenomenon. The following research with the lamp manufactory Philips Lighting, established that the red part of the spectrum in the emitted light was responsible for this circling phenomenon and that removing the long wavelength components of the spectrum reduces the visual and orientation impact on birds (Poot et al., 2008). On the basis of these studies, a light source (spectral modified lighting or green light) was developed that reduces this fatal bird attraction, creates safe working conditions and results in a highly positive public response. The only unresolved safety factor was conflicting opinions on helicopter approach and landing. Circumstantial evidence was found that window glazing with a UV-blue filter – as used in some helicopters - is the cause for this. This paper reviews the experience regarding the use of spectral modified lighting (and related approaches) and puts them in a new perspective. It elaborates on safety factors, especially those related to helicopter approach and landing and discusses the potential application of the technology for new projects. Drawing on recent experience in Europe and North America to apply spectral modified lighting, the paper address certification and permitting issues and briefly discuss emerging regulatory trends affecting this technology.

In this study, we describe and compare the duration and timing of post-breeding moult of primary and secondary wing feathers, tail feathers, wing coverts and body feathers in captive partially migratory and non-migratory Australian silvereyes (Zosterops lateralis). This study allowed us to follow individual birds through the course of their moult and record the progression of moult in two populations. Both groups of birds underwent a conventional (or basic) post-breeding moult. While all birds followed a similar pattern of feather replacement, differences were found in the timing and duration of moult between migratory and non-migratory birds. The migratory birds generally started their moult earlier in the year and completed it before the non-migratory birds. The migratory birds revealed an overall uniformity in the timing and duration of their moult, while the non-migratory birds showed a greater degree of variability between individuals.

The major source of several influenza viruses in other species are aquatic birds. Long distances travel is carried out by many migratory bird species between their breeding grounds and non-breeding areas. These migratory birds as well as wild birds are considered as reservoirs of majority of influenza A viruses. The geospatial analysis of the pathways of migratory birds present in different geographical locations will throw further light on their role in influenza virus epidemiology. The influenza virus dynamics among migratory wild birds and mammals including humans are closely linked as is evident from H1N1 spread. It is important to note that the migratory water fowls play a negative role as far as the economic benefit out of poultry industry is concerned and imposes threat to lives of human as well, because of their capability to transmit the highly pathogenic avian influenza (HPAI) virus across the continents. Interestingly, several species of familiar songbirds or perching birds act as bridge species and has a possible role in transmitting the H5N1 AI to or from wild habitat. Surveillance and tracking of migratory and resident wild birds, utilisation of ornithological expertise, and analysis of the H5N1 ecology are needed for increasing our knowledge about strain- or host-specific pathogenecity, degree of shedding of virus and the routes of transmission between wild birds. In this aspect, it is quiet noteworthy that 13 membered International Scientific Task Force including UN bodies, wildlife treaties and specialist intergovernmental as well as non-governmental organizations have been created on the ground of various scientific studies concerning the role of migratory birds as potential transmitter of H5N1 subtype of Highly Pathogenic Avian Influenza (HPAI) virus.

It has been hypothesized that individuals who have higher demands for spatially based behaviours should show increases in hippocampal attributes. Some avian species have been shown to use a spatially based representation of their environment during migration. Further, differences in hippocampal attributes have been shown between migratory and non-migratory subspecies as well as between individuals with and without migratory experience (juveniles versus adults). We tested whether migratory behaviour might also be associated with increased hippocampal neurogenesis, and whether potential differences track previously reported differences in hippocampal attributes between a migratory (Zonotrichia leucophrys gambelii) and non-migratory subspecies (Z. l. nuttalli) of white-crowned sparrows. We found that non-migratory adults had relatively fewer numbers of immature hippocampal neurons than adult migratory birds, while adult non-migrants had a lower density of new hippocampal neurons than adult and juvenile migratory birds and juvenile non-migratory birds. Our results suggest that neurogenesis decreases with age, as juveniles, regardless of migratory status, exhibit similar and higher levels of neurogenesis than non-migratory adults. However, our results also suggest that adult migrants may either seasonally increase or maintain neurogenesis levels comparable to those found in juveniles. Our results thus suggest that migratory behaviour in adults is associated with maintained or increased neurogenesis and the differential production of new neurons may be the mechanism underpinning changes in the hippocampal architecture between adult migratory and non-migratory birds.

Recent increases in human disturbance pose significant threats to migratory species using collective movement strategies. Key threats to migrants may differ depending on behavioural traits (e.g. collective navigation), taxonomy and the environmental system (i.e. freshwater, marine or terrestrial) associated with migration. We quantitatively assess how collective navigation, taxonomic membership and environmental system impact species' vulnerability by (i) evaluating population change in migratory and non-migratory bird, mammal and fish species using the Living Planet Database (LPD), (ii) analysing the role of collective navigation and environmental system on migrant extinction risk using International Union for Conservation of Nature (IUCN) classifications and (iii) compiling literature on geographical range change of migratory species. Likelihood of population decrease differed by taxonomic group: migratory birds were more likely to experience annual declines than non-migrants, while mammals displayed the opposite pattern. Within migratory species in IUCN, we observed that collective navigation and environmental system were important predictors of extinction risk for fishes and birds, but not for mammals, which had overall higher extinction risk than other taxa. We found high phylogenetic relatedness among collectively navigating species, which could have obscured its importance in determining extinction risk. Overall, outputs from these analyses can help guide strategic interventions to conserve the most vulnerable migrations.This article is part of the theme issue 'Collective movement ecology'.

Pathogens Transmitted by Migratory Birds: Threat Perceptions to Poultry Health and Production

Worldwide, bacteria are the most ubiquitous microorganisms, and it has been extensively demonstrated that migratory wild birds can increase bacterial global scale dispersion through long-distance migration and dispersal. The microbial community hosted by wild birds can be highly diverse, including pathogenic strains that can contribute to infections and disease spread. This study focused on feather and plumage bacteria within bird microbial communities. Samples were collected during ornithological activities in a bird ringing station. Bacterial identification was carried out via DNA barcoding of the partial 16S rRNA gene. Thirty-seven isolates of bacteria were identified on the chest feathers of 60 migratory birds belonging to three trans-Saharan species: Muscicapa striata, Hippolais icterina, and Sylvia borin. Our results demonstrate the possibility of bacterial transfer, including pathogens, through bird migration between very distant countries. The data from the analysis of plumage bacteria can aid in the explanation of phenomena such as migratory birds’ fitness or the development of secondary sexual traits. Moreover, these results have deep hygienic–sanitary implications, since many bird species have synanthropic behaviors during their migration that increase the probability of disease spread.

Highly pathogenic avian influenza virus (HPAIV) causes lethal infection in gallinaceous poultry such as chickens. HPAIV is generated when a nonpathogenic virus brought in by migratory birds from nesting lakes in the north is transmitted to chickens via domestic ducks, geese, quails, etc. and acquires pathogenicity for chickens with repeated multiple infections in the chicken population. Now H5N1 HPAIV has spread to 62 countries in Eurasia and Africa. H5N1 HPAIVs were isolated from dead water birds in Mongolia and Hokkaido, Japan on the way back to their nesting lakes in Siberia in April to May 2005, 2006, 2008, 2009 and 2010. It is concerned that these HPAI viruses may perpetuate in the lakes where migratory water birds nest in summer. On 14th October in 2010, 2 H5N1 HPAIVs were isolated from fecal samples of ducks who flew from Siberia to Ohnuma Lake in Wakkanai, Hokkaido, Japan. Since then, 24 outbreaks of avian influenza due to infection with the H5N1 viruses closely related to the viruses isolated from fecal samples of ducks in Hokkaido in October 2010 have occurred in 9 different prefectures in Japan until the end of March 2011. The other serious concern is that 620 people have been infected with the H5N1 virus, 60% of whom died in 15 countries since 2004 (as of 15 February 2013). It is noted that most of the human cases (86%) are in China, Viet Nam, Indonesia, and Egypt where bird flu vaccines are used. It is strongly proposed to eradicate the H5N1 HPAIVs from Asia by stamping-out without misuse of vaccine through international collaboration under the umbrella of ”One World, One Health” concept.

H1 avian influenza viruses (AIVs) isolated from migratory birds and domestic ducks from 2003 to 2007 were analyzed to determine their genetic relationship. Phylogenic analysis with nucleotide sequences of all eight gene segments showed that 13 H1 AIVs from migratory birds and domestic ducks belonged to Eurasian avian lineages and were closely related to each other. Compared with H1 influenza viruses of swine or human origin in Korea, there was no evidence of reassortment among the human, swine, and avian hosts. Our results show that H1 AIVs isolated in Korea from 2003 to 2007 were genetically stable. However, continued surveillance is needed considering the role of migratory birds and domestic duck as a source of AIVs.

BackgroundInfection with H5N1 highly pathogenic avian influenza viruses (HPAIVs) of domestic poultry and wild birds has spread to more than 60 countries in Eurasia and Africa. It is concerned that HPAIVs may be perpetuated in the lakes in Siberia where migratory water birds nest in summer. To monitor whether HPAIVs circulate in migratory water birds, intensive surveillance of avian influenza has been performed in Mongolia and Japan in autumn each year. Until 2008, there had not been any H5N1 viruses isolated from migratory water birds that flew from their nesting lakes in Siberia. In autumn 2009, A/mallard/Hokkaido/24/09 (H5N1) (Mal/Hok/24/09) was isolated from a fecal sample of a mallard (Anas platyrhynchos) that flew from Siberia to Hokkaido, Japan. The isolate was assessed for pathogenicity in chickens, domestic ducks, and quails and analyzed antigenically and phylogenetically.ResultsNo clinical signs were observed in chickens inoculated intravenously with Mal/Hok/24/09 (H5N1). There was no viral replication in chickens inoculated intranasally with the isolate. None of the domestic ducks and quails inoculated intranasally with the isolate showed any clinical signs. There were no multiple basic amino acid residues at the cleavage site of the hemagglutinin (HA) of the isolate. Each gene of Mal/Hok/24/09 (H5N1) is phylogenetically closely related to that of influenza viruses isolated from migratory water birds that flew from their nesting lakes in autumn. Additionally, the antigenicity of the HA of the isolate was similar to that of the viruses isolated from migratory water birds in Hokkaido that flew from their northern territory in autumn and different from those of HPAIVs isolated from birds found dead in China, Mongolia, and Japan on the way back to their northern territory in spring.ConclusionMal/Hok/24/09 (H5N1) is a non-pathogenic avian influenza virus for chickens, domestic ducks, and quails, and is antigenically and genetically distinct from the H5N1 HPAIVs prevailing in birds in Eurasia and Africa. H5 viruses with the HA gene of HPAIV had not been isolated from migratory water birds in the surveillance until 2009, indicating that H5N1 HPAIVs had not become dominant in their nesting lakes in Siberia until 2009.

The continued evolution and emergence of novel influenza viruses in wild and domestic animals poses an increasing public health risk. Two human cases of H3N8 avian influenza virus infection in China in 2022 have caused public concern regarding the risk of transmission between birds and humans. However, the prevalence of H3N8 avian influenza viruses in their natural reservoirs and their biological characteristics are largely unknown. To elucidate the potential threat of H3N8 viruses, we analyzed five years of surveillance data obtained from an important wetland region in eastern China and evaluated the evolutionary and biological characteristics of 21 H3N8 viruses isolated from 15,899 migratory bird samples between 2017 and 2021. Genetic and phylogenetic analyses showed that the H3N8 viruses circulating in migratory birds and ducks have evolved into different branches and have undergone complicated reassortment with viruses in waterfowl. The 21 viruses belonged to 12 genotypes, and some strains induced body weight loss and pneumonia in mice. All the tested H3N8 viruses preferentially bind to avian-type receptors, although they have acquired the ability to bind human-type receptors. Infection studies in ducks, chickens and pigeons demonstrated that the currently circulating H3N8 viruses in migratory birds have a high possibility of infecting domestic waterfowl and a low possibility of infecting chickens and pigeons. Our findings imply that circulating H3N8 viruses in migratory birds continue to evolve and pose a high infection risk in domestic ducks. These results further emphasize the importance of avian influenza surveillance at the wild bird and poultry interface.

The cases of human infections with H10N8 viruses identified in late 2013 and early 2014 in Jiangxi, China, have raised concerns over the origin, prevalence, and development of these viruses in this region. Our long-term influenza surveillance of poultry and migratory birds in southern China in the past 12 years showed that H10 influenza viruses have been introduced from migratory to domestic ducks over several winter seasons at sentinel duck farms at Poyang Lake, where domestic ducks share their water body with overwintering migratory birds. H10 viruses were never detected in terrestrial poultry in our survey areas until August 2013, when they were identified at live-poultry markets in Jiangxi. Since then, we have isolated 124 H10N8 or H10N6 viruses from chickens at local markets, revealing an ongoing outbreak. Phylogenetic analysis of H10 and related viruses showed that the chicken H10N8 viruses were generated through multiple reassortments between H10 and N8 viruses from domestic ducks and the enzootic chicken H9N2 viruses. These chicken reassortant viruses were highly similar to the human isolate, indicating that market chickens were the source of human infection. Recently, the H10 viruses further reassorted, apparently with H5N6 viruses, and generated an H10N6 variant. The emergence and prevalence of H10 viruses in chickens and the occurrence of human infections provide direct evidence of the threat from the current influenza ecosystem in China. After the outbreak of avian-origin H7N9 influenza viruses in China, fatal human infections with a novel H10N8 virus were reported. Utilizing data from 12 years of influenza surveillance in southern China, we showed that H10 viruses were regularly introduced by migratory ducks to domestic ducks on Poyang Lake, a major aggregative site of migratory birds in Asia. The H10 viruses were maintained and amplified in domestic ducks and then transmitted to chickens and reassorted with enzootic H9N2 viruses, leading to an outbreak and human infections at live-poultry markets. The emergence of the H10N8 virus, following a pathway similar to that of the recent H7N9 virus, highlights the role of domestic ducks and the current influenza ecosystem in China that facilitates influenza viruses moving from their reservoir hosts through the live-poultry system to cause severe consequences for public health.

IntroductionMore than 70 outbreaks of the highly pathogenic avian influenza (HPAI) H5N1 have been reported in poultry in the western and north-eastern parts of India. Therefore, in view of the recent HPAI H5N1 outbreaks in poultry, active AI surveillance encompassing wild, resident, migratory birds and poultry was undertaken during 2009–2011 in the State of West Bengal.MethodsA total of 5722 samples were collected from West Bengal; 3522 samples (2906 fecal droppings + 616 other environmental samples) were from migratory birds and 2200 samples [1604 tracheal, cloacal swabs, environmental samples, tissue samples + 596 blood (serum)] were from domestic ducks and poultry. All tracheal, cloacal and environmental samples were processed for virus isolation. Virus isolates were detected using hemagglutination assay and identified using hemagglutination inhibition (HI) and reverse transcriptase polymerase chain reaction (RT-PCR) assays. Sequencing and phylogenetic analysis of partial region of the hemagglutinin and neuraminidase genes was done. Intravenous pathogenicity index assays were performed in chickens to assess pathogenicity of AI virus isolates. Serum samples were tested for detection of antibodies against AI viruses using HI assay.ResultsA total of 57 AI H9N2, 15 AI H4N6 and 15 Newcastle Disease (NDV) viruses were isolated from chickens, from both backyard and wet poultry markets; AI H4N6 viruses were isolated from backyard chickens and domestic ducks. Characterization of AI H9N2 and H4N6 viruses revealed that they were of low pathogenicity. Domestic ducks were positive for antibodies against H5 and H7 viruses while chickens were positive for presence of antibodies against AI H9N2 and NDV.ConclusionsIn the current scenario of HPAI H5N1 outbreaks in West Bengal, this report shows presence of low pathogenic AI H9N2 and H4N6 viruses in chickens and domestic ducks during the period 2009–2011. This is the first report of isolation of H4N6 from India. Antibodies against AI H5 and H7 in ducks highlight the probable role of domestic ducks in the transmission of AI viruses. Human infections of H9N2 have been reported from China and Hong Kong. This necessitates implementation of prevention and control measures to limit the spread of AI viruses.