Migratory patterns of two major influenza virus host species on tropical islands.

Animal migration is a major driver of infectious agent dispersal. Duck and seabird migrations, for instance, play a key role in the spatial transmission dynamics and gene flow of avian influenza viruses (AIV), worldwide. On tropical islands, brown and lesser noddies (Anous stolidus and Anous tenuirostris) may be important AIV hosts, but the lack of knowledge on their migratory behaviour limits our understanding of virus circulation in island networks. Here we show that high connectivity between islands generated by non-breeding dispersive behaviours may be a major driver in the spread and the maintenance of AIV among tropical islands of the western Indian Ocean. Tracking data highlight two types of dispersive behaviours during the non-breeding season: birds either staying in the vicinity of their breeding ground (on Bird Island, Seychelles), or moving to and roosting on other islands in the western Indian Ocean. Migrant birds used a wide range of roosting places from the Tanzanian coasts to the Maldives archipelago and Tromelin Island. Epidemiological data confirm that brown and lesser noddies are major hosts for AIV, although significant variations of seroprevalence between species suggest that other biological and ecological drivers could be involved in virus infection and transmission dynamics.

Exposure of pelagic seabirds to Toxoplasma gondii in the Western Indian Ocean points to an open sea dispersal of this terrestrial parasite.

Toxoplasma gondii is a protozoan parasite that uses felids as definitive hosts and warm-blooded animals as intermediate hosts. While the dispersal of T. gondii infectious oocysts from land to coastal waters has been well documented, transmission routes to pelagic species remain puzzling. We used the modified agglutination test (MAT titre ≥ 10) to detect antibodies against T. gondii in sera collected from 1014 pelagic seabirds belonging to 10 species. Sampling was carried out on eight islands of the Western Indian Ocean: Reunion and Juan de Nova (colonized by cats), Cousin, Cousine, Aride, Bird, Europa and Tromelin islands (cat-free). Antibodies against T. gondii were found in all islands and all species but the great frigatebird. The overall seroprevalence was 16.8% [95% CI: 14.5%-19.1%] but significantly varied according to species, islands and age-classes. The low antibody levels (MAT titres = 10 or 25) detected in one shearwater and three red-footed booby chicks most likely resulted from maternal antibody transfer. In adults, exposure to soils contaminated by locally deposited oocysts may explain the detection of antibodies in both wedge-tailed shearwaters on Reunion Island and sooty terns on Juan de Nova. However, 144 adults breeding on cat-free islands also tested positive. In the Seychelles, there was a significant decrease in T. gondii prevalence associated with greater distances to cat populations for species that sometimes rest on the shore, i.e. terns and noddies. This suggests that oocysts carried by marine currents could be deposited on shore tens of kilometres from their initial deposition point and that the number of deposited oocysts decreases with distance from the nearest cat population. The consumption of fishes from the families Mullidae, Carangidae, Clupeidae and Engraulidae, previously described as T. gondii oocyst-carriers (i.e. paratenic hosts), could also explain the exposure of terns, noddies, boobies and tropicbirds to T. gondii. Our detection of antibodies against T. gondii in seabirds that fish in the high sea, have no contact with locally contaminated soils but frequent the shores and/or consume paratenic hosts supports the hypothesis of an open-sea dispersal of T. gondii oocysts by oceanic currents and/or fish.

Eradication of common mynas Acridotheres tristis from Denis Island, Seychelles.

BACKGROUND: In Seychelles, the common myna has been shown to have a negative impact on endangered endemic birds on Denis Island, interfering with breeding attempts and attacking adult endemic birds at their nests. This stimulated an attempt to eradicate the island's mynas. RESULTS: The eradication was undertaken in three phases, overall killing 1186 mynas and lasting 5 years. Decoy trapping was the most effective method for catching mynas, but the last birds were shot. Decoy trapping was compromised by catches of non-target species. Data collection from killed birds indicated that trapping did not favour either sex, and that most breeding occurred during the wetter season, November to March. CONCLUSIONS: Eradication of mynas from small tropical islands is feasible. The Denis Island eradication was prolonged by difficulties in management and staffing. Using volunteers, the cost of the eradication was similar to that of eradicating rodents from the island. In future eradication attempts in Seychelles, possible food stress during the drier season (May to September) might facilitate trapping at this time. Habitat management, especially the removal of short mown grass, could enhance eradication progress. Continued monitoring is needed to confirm eradication and detect any immigration, and also to record responses in the endemic birds. © 2016 Society of Chemical Industry.

Influenza A virus on oceanic islands: host and viral diversity in seabirds in the Western Indian Ocean.

Ducks and seabirds are natural hosts for influenza A viruses (IAV). On oceanic islands, the ecology of IAV could be affected by the relative diversity, abundance and density of seabirds and ducks. Seabirds are the most abundant and widespread avifauna in the Western Indian Ocean and, in this region, oceanic islands represent major breeding sites for a large diversity of potential IAV host species. Based on serological assays, we assessed the host range of IAV and the virus subtype diversity in terns of the islands of the Western Indian Ocean. We further investigated the spatial variation in virus transmission patterns between islands and identified the origin of circulating viruses using a molecular approach. Our findings indicate that terns represent a major host for IAV on oceanic islands, not only for seabird-related virus subtypes such as H16, but also for those commonly isolated in wild and domestic ducks (H3, H6, H9, H12 subtypes). We also identified strong species-associated variation in virus exposure that may be associated to differences in the ecology and behaviour of terns. We discuss the role of tern migrations in the spread of viruses to and between oceanic islands, in particular for the H2 and H9 IAV subtypes.

Relationship between phosphodiesterase type 4 inhibition and anti-inflammatory activity of CI-1044 in rat airways.

The anti-inflammatory effects of CI-1044 and of the other selective PDE4 inhibitors rolipram and cilomilast were investigated in Brown-Norway (BN) rats, against lipopolysaccharide-induced tumor necrosis factor alpha (TNFalpha) production in whole blood and antigen-induced lung eosinophilia. In vitro, CI-1044 inhibited TNFalpha production with an IC(50) of 0.31 microm being equipotent to Cilomilast (IC(50) = 0.26 microm) and rolipram (IC(50) = 0.11 microm). Given orally, CI-1044 inhibited ex vivo TNFalpha production with an ED(50) value of 0.4 mg/kg after single administration, whereas rolipram (ED(50) = 1.4 mg/kg) and cilomilast (ED(50) = 1.6 mg/kg) were less potent. In the same ex vivo setting, but given repeatedly, CI-1044 led to an ED(50) of 0.5 mg/kg corresponding to a plasma concentration of 82.6 ng/mL (0.22 microm). In vivo, CI-1044 prevented TNFalpha release with an ED(50) of 1 mg/kg p.o. and inhibited ovalbumin-induced lung eosinophilia following single or repeated oral administration with an ED(50) of 3.25 and 4.8 mg/kg p.o., respectively, suggesting the absence of pharmacological tolerance. CI-1044 in this model was equipotent to rolipram (81% inhibition at 10 mg/kg) but better than cilomilast (25% inhibition at 10 mg/kg). Finally, CI-1044 (10 mg/kg) inhibited inflammatory cell recruitment with a long duration of action (up to 8 h) and was still active when given post-challenge. Our data show that CI-1044 is an orally active PDE4 inhibitor that may be used as an anti-inflammatory therapy in lung inflammatory diseases.