Study says H5N1 has varied effects in small land birds

first_imgOct 18, 2007 (CIDRAP News) – A study on the effects of the H5N1 avian influenza virus on small land birds suggests it is often lethal in sparrows but has lesser effects on starlings and pigeons and does not readily spread to other birds of the same species.However, the researchers say their findings also suggest that sparrows and starlings could potentially spread the virus to poultry and mammals.The results of the study, conducted at St Jude Children’s Research Hospital in Memphis, were published early online by Emerging Infectious Diseases.Scientists have fleshed out some H5N1 patterns in waterfowl species, which have been shown to shed the virus for prolonged periods and are thought to play some role—along with the poultry business—in the geographic spread among the world’s poultry populations. However, less is known about small terrestrial birds, which also intermingle with waterfowl and poultry.To gauge how the H5N1 virus behaves in small birds, the researchers inoculated sparrows, starlings, and pigeons with four different strains that were isolated from birds. Two of the strains had previously been shown to infect waterfowl in Thailand, and two were recently isolated during wild-bird surveillance in Hong Kong.The sparrows and starlings used in the study were captured in the wild, while 6-week old Carneux pigeons were bought from supply houses. At the start of the study, the authors obtained cloacal swabs from the birds to rule out existing influenza A infections.After the birds were inoculated with the H5N1 strains, researchers placed them in cages with uninfected birds of the same species for 14 days to gauge virus transmission. The ratio of infected to uninfected birds was 1:1 for sparrows and starlings and 2:3 for pigeons.The birds were monitored each day for death and illness, and oropharyngeal and cloacal swabs were collected on days 2, 4, 6, 8, and 11 for sparrows and starlings and on days 3, 5, and 7 for pigeons. At the end of the 14-day period, the investigators collected serum samples from the inoculated and contact birds for hemagglutanin-inhibition testing.Death rates were highest for the sparrows: 66% to 100% of them died, depending on the H5N1 strain they received. High viral loads were detected in dead sparrows’ brain and lung tissues. However, none of the starlings or pigeons died.Regular testing after inoculation showed that all of the sparrows and starlings were infected, but infection in pigeons depended on the strain of the virus. One of the Hong Kong strains infected both sparrows and starlings, as well as all of the inoculated pigeons, though the authors found the viruses replicated relatively poorly in the pigeons.Virus titers showed sparrows and starlings shed similar amounts of the virus, but titers from cloacal swabs of sparrows were higher than those from the starlings.The researchers found no evidence of spread of the virus among the sparrows and pigeons. Only one starling showed evidence of transmission, involving one of the Hong Kong strains.The authors concluded that that the birds varied in their susceptibility to the H5N1 viruses but that transmission to the contact birds was infrequent.Compared to earlier reports on the susceptibility of sparrows, starlings, and pigeons to a 1997 Hong Kong H5N1 virus, the current study suggests that the bird species are more susceptible to the more recent H5N1 isolates used in the study.”Although drawing conclusions on the basis of a single 1997 isolate is inappropriate, these data are consistent with studies that have demonstrated increased virulence or host range for recent influenza [H5N1] viruses in mammalian species,” the authors write.A key question is whether smaller wild birds can be intermediate hosts or long-term reservoirs for the H5N1 virus, the researchers point out. The results in sparrows suggest that they could potentially infect poultry and mammals, but, given the high death rate, wouldn’t likely serve as a reservoir for prolonged viral shedding. Starlings, because they survived and shed the virus longer, could act as an intermediate host, but transmission evidence in the study was limited, the report says. The authors suggest that the role of pigeons in spreading the virus may be minor because they shed only small amounts of the virus and didn’t transmit the disease to other pigeons.The researchers conclude that terrestrial wild bird species vary considerably in their susceptibility to H5N1 virus strains, and some species, such as sparrows, could suffer substantial losses during H5N1 outbreaks. Also, they write that mutations in circulating H5N1 viruses could enhance the role of sparrows and starlings as intermediate hosts.Boon ACM, Sandbulte MR, Seiler P, et al. Role of terrestrial wild birds in ecology of influenza A virus (H5N1). Emerg Infect Dis 2007 Nov 13(11) [Full text]last_img read more

Lookman shines but Leipzig crash to lowly Cologne

first_imgWhen Portugal international Bruma crossed to the far post, Lookman, 20, nudged the ball onto the woodwork and French striker Jean-Kevin Augustin tapped home the rebound.Having scored on his Bundesliga debut three weeks ago, Lookman played well before being replaced by Danish forward Yussuf Poulsen for the last half hour.With Lookman on the Leipzig bench, Cologne roared back with two goals in the final 20 minutes.“If you play like we did in the second half then you don’t deserve to take a point,” moaned Leipzig midfielder Marcel Sabitzer.Vincent Koziello, Cologne’s new signing from French league side Nice in January, smashed home a left-footed shot on 70 minutes to claim his first Bundesliga goal.Then substitute midfielder Leonardo Bittencourt, who has just recovered from a groin injury, fired home at the back post seven minutes later.The defeat leaves Leipzig sixth while Cologne remain eight points from safety with 10 games left.“In the Bundesliga, you can’t just play well for 45 minutes,” fumed Leipzig coach Ralph Hasenhuettl.“You can’t play football much better than we did in the first half, but after the break, it was as if the plug had been pulled — there was nothing left.”– Bentaleb’s sweet return –Earlier, Schalke climbed from sixth to third as Nabil Bentaleb scored on his comeback to seal their 2-0 victory at 10-man Bayer Leverkusen.It was a sweet return for the ex-Tottenham Hotspur midfielder, who was dropped from Schalke’s squad a fortnight ago and told to improve his attitude.Bentaleb’s penalty just before the final whistle capped a deserved win for Schalke who had taken the lead with just 11 minutes gone in Leverkusen.Guido Burgstaller flicked the ball over a defender and fired into the bottom left corner of the net from 15 yards.“We said clearly that we want to perform well and we succeeded in doing that,” said Schalke’s director of sport Christian Heidel.However, Heidel revealed win was overshadowed by injuries to two Schalke fans, one of whom fell down stairs and is “in critical condition”, after suffering a head trauma.Schalke will be without Burgstaller for their next league game at Hertha Berlin after he picked up a first-half booking — his fifth yellow card of the season.Leverkusen had defensive midfielder Dominik Kohr sent off for a second yellow card after 38 minutes.Schalke poured forward and sealed the win thanks to a Leverkusen mistake.Teenage Greece defender Panagiotis Retsos sent Swiss striker Breel Embolo tumbling in the area and when referee Daniel Siebert pointed to the spot, Bentaleb, a second-half replacement, drilled home the penalty on 89 minutes.“We played very well and created a lot of chances in the first half,” said Schalke coach Domenico Tedesco.“We counter attacked well after the break and I am happy to go home with the three points.”Schalke are level with second-placed Borussia Dortmund on 40 points — a massive 20 behind runaway league leaders Bayern Munich.The Bavarian giants were held to a goalless draw at home to Hertha Berlin on Saturday, the first time they had failed to score a league goal at the Allianz Arena since May 2015.Despite outshooting Hertha 19-5 — Bayern could not break through, which cost them two possible records.Top-scorer Robert Lewandowski, who had 10 shots on goal, missed the out-right record of scoring in 12 consecutive home league games.Jupp Heynckes also missed the chance to become the first Bayern coach to claim 15 straight wins in all competitions.0Shares0000(Visited 1 times, 1 visits today) 0Shares0000Young English midfielder Ademola Lookman’s starring performance couldn’t save Leipzig from defeat © AFP / ROBERT MICHAELBERLIN, Germany, Feb 25 – Ademola Lookman created a goal but RB Leipzig squandered the chance to go second in the Bundesliga on Sunday after crashing to a 2-1 defeat at home to bottom side Cologne.Lookman, an England Under-21 winger on loan from Everton, shone during his 59 minutes, hitting the post in the move that led to the opening goal on five minutes at Leipzig’s Red Bull Arena.last_img read more