Co-Circulation and Excretion Dynamics of Diverse Rubula- and Related Viruses in Egyptian Rousette Bats from South Africa.

The Egyptian rousette bat (Rousettus aegyptiacus) has previously been implicated as the natural host of a zoonotic rubulavirus; however, its association with rubulaviruses has been studied to a limited extent. Urine, spleen, and other organs collected from the R. aegyptiacus population within South Africa were tested with a hemi-nested RT-PCR assay targeting a partial polymerase gene region of viruses from the Avula- and Rubulavirus genera. Urine was collected over a 14-month period to study the temporal dynamics of viral excretion. Diverse rubulaviruses, including viruses related to human mumps and parainfluenza virus 2, were detected. Active excretion was identified during two peak periods coinciding with the host reproductive cycle. Analysis of additional organs indicated co-infection of individual bats with a number of different putative rubulaviruses, highlighting the limitations of using a single sample type when determining viral presence and diversity. Our findings suggest that R. aegyptiacus can harbor a range of Rubula- and related viruses, some of which are related to known human pathogens. The observed peaks in viral excretion represents potential periods of a higher risk of virus transmission and zoonotic disease spill-over.

Biological and phylogenetic characterization of a novel hemagglutination-negative avian avulavirus 6 isolated from wild waterfowl in China.

Up to now only nine whole genome sequences of avian avulavirus 6 (AAvV-6) had been documented in the world since the first discovery of AAvV-6 (AAvV-6/duck/HongKong/18/199/77) at a domestic duck in 1977 from Hong Kong of China. Very limited information is known about the regularities of transmission, genetic and biological characteristics of AAvV-6 because of the lower isolation rate and mild losses for poultry industry. To better further explore the relationships among above factors, an AAvV-6 epidemiological surveillance of domestic poultry and wild birds in six provinces of China suspected of sites of inter-species transmission and being intercontinental flyways during the year 2013-2017 was conducted. Therefore, 9,872 faecal samples from wild birds and 1,642 cloacal and tracheal swab samples from clinically healthy poultry of live bird market (LBM) were collected respectively. However, only one novel hemagglutination-negative AAvV-6 isolate (AAvV-6/mallard/Hubei/2015) was isolated from a fresh faecal sample obtained from mallard at a wetland of Hubei province. Sequencing and phylogenetic analyses of this AAvV-6 isolate (AAvV-6/mallard/Hubei/2015) indicated that this isolate grouping to genotype I were epidemiological intercontinentally linked with viruses from the wild birds in Europe and America. Meanwhile, at least two genotypes (I and II) are existed within serotype AAvV-6. In additional, this novel hemagglutination-negative AAvV-6 isolate in chicken embryos restored its hemagglutination when pre-treated with trypsin. These findings, together with data from other AAvV-6, suggest potential epidemiological intercontinental spreads among AAvV-6 transmission by wild migratory birds, and reveal potential threats to wild birds and domestic poultry worldwide.

Dispersal and Transmission of Avian Paramyxovirus Serotype 4 among Wild Birds and Domestic Poultry.

Avian paramyxovirus serotype 4 (APMV-4) is found sporadically in wild birds worldwide, and it is an economically important poultry pathogen. Despite the existence of several published strains, very little is known about the distribution, host species, and transmission of APMV-4 strains. To better understand the relationships among these factors, we conducted an APMV-4 surveillance of wild birds and domestic poultry in six provinces of China suspected of being intercontinental flyways and sites of interspecies transmission. APMV-4 surveillance was conducted in 9,160 wild birds representing seven species, and 1,461 domestic poultry in live bird markets (LMBs) from December 2013 to June 2016. The rate of APMV-4 isolation was 0.10% (11/10,621), and viruses were isolated from swan geese, bean geese, cormorants, mallards, and chickens. Sequencing and phylogenetic analyses of the 11 isolated viruses indicated that all the isolates belonging to genotype I were epidemiologically connected with wild bird-origin viruses from the Ukraine and Italy. Moreover, chicken-origin APMV-4 strains isolated from the LBMs were highly similar to wild bird-origin viruses from nearby lakes with free-living wild birds. In additional, a hemagglutination-negative APMV-4 virus was identified. These findings, together with recent APMV-4 studies, suggest potential virus interspecies transmission between wild birds and domestic poultry, and reveal possible epidemiological intercontinental connections between APMV-4 transmission by wild birds.

Limited evidence of intercontinental dispersal of avian paramyxovirus serotype 4 by migratory birds.

Avian paramyxovirus serotype 4 (APMV-4) is a single stranded RNA virus that has most often been isolated from waterfowl. Limited information has been reported regarding the prevalence, pathogenicity, and genetic diversity of AMPV-4. To assess the intercontinental dispersal of this viral agent, we sequenced the fusion gene of 58 APMV-4 isolates collected in the United States, Japan and the Ukraine and compared them to all available sequences on GenBank. With only a single exception the phylogenetic clades of APMV-4 sequences were monophyletic with respect to their continents of origin (North America, Asia and Europe). Thus, we detected limited evidence for recent intercontinental dispersal of APMV-4 in this study.

Wild bird surveillance for avian paramyxoviruses in the Azov-black sea region of Ukraine (2006 to 2011) reveals epidemiological connections with Europe and Africa.

Despite the existence of 10 avian paramyxovirus (APMV) serotypes, very little is known about the distribution, host species, and ecological factors affecting virus transmission. To better understand the relationship among these factors, we conducted APMV wild bird surveillance in regions of Ukraine suspected of being intercontinental (north to south and east to west) flyways. Surveillance for APMV was conducted in 6,735 wild birds representing 86 species and 8 different orders during 2006 to 2011 through different seasons. Twenty viruses were isolated and subsequently identified as APMV-1 (n = 9), APMV-4 (n = 4), APMV-6 (n = 3), and APMV-7 (n = 4). The highest isolation rate occurred during the autumn migration (0.61%), with viruses isolated from mallards, teals, dunlins, and a wigeon. The rate of isolation was lower during winter (December to March) (0.32%), with viruses isolated from ruddy shelducks, mallards, white-fronted geese, and a starling. During spring migration, nesting, and postnesting (April to August) no APMV strains were isolated out of 1,984 samples tested. Sequencing and phylogenetic analysis of four APMV-1 and two APMV-4 viruses showed that one APMV-1 virus belonging to class 1 was epidemiologically linked to viruses from China, three class II APMV-1 viruses were epidemiologically connected with viruses from Nigeria and Luxembourg, and one APMV-4 virus was related to goose viruses from Egypt. In summary, we have identified the wild bird species most likely to be infected with APMV, and our data support possible intercontinental transmission of APMVs by wild birds.

Avian paramyxoviruses in shorebirds and gulls.

There are nine serotypes of avian paramyxovirus (APMV), including APMV-1, or Newcastle disease virus. Although free-flying ducks and geese have been extensively monitored for APMV, limited information is available for species in the order Charadriiformes. From 2000 to 2005 we tested cloacal swabs from 9,128 shorebirds and gulls (33 species, five families) captured in 10 states within the USA and in three countries in the Caribbean and South America. Avian paramyxoviruses were isolated from 60 (0.7%) samples by inoculation of embryonating chicken eggs; isolates only included APMV-1 and APMV-2. Two isolates (APMV-2) were made from gulls and 58 isolates (APMV-1 [41 isolates] and APMV-2 [17 isolates]) were made from shorebirds. All of the positive shorebirds were sampled at Delaware Bay (Delaware and New Jersey) and 45 (78%) of these isolates came from Ruddy Turnstones (Arenaria interpres). The APMV-1 infection rate was higher among Ruddy Turnstones compared with other shorebird species and varied by year. Avian paramyxovirus-2 was isolated from two of 394 (0.5%) Ruddy Turnstones at Delaware Bay in 2001 and from 13 of 735 (1.8%) Ruddy Turnstones during 2002. For both APMV-1 and APMV-2, infection rates were higher among Ruddy Turnstones sampled on the south shore of Delaware Bay compared to north shore populations. This spatial variation may be related to local movements of Ruddy Turnstones within this ecosystem. The higher prevalence of APMV in Ruddy Turnstones mirrors results observed for avian influenza viruses in shorebirds and may suggest similar modes of transmission.