Prerelease publication of Avian H11N9 in U.S.



http://www.cdc.gov/ncidod/EID/vol12no08/06-0492.htm
Volume 12, Number 8–August 2006 --- Ahead of print !
Volume 12, Number 8–August 2006
Dispatch
Avian Influenza among Waterfowl Hunters and Wildlife Professionals
James S. Gill,* Richard Webby,† Mary J.R. Gilchrist,* and Gregory C. Gray‡
*University of Iowa Hygienic Laboratory, Iowa City, Iowa, USA; †St Jude Children's Research Hospital, Memphis, Tennessee, USA; and ‡University of Iowa College of Public Health, Iowa City, Iowa, USA

Suggested citation for this article

We report serologic evidence of avian influenza infection in 1 duck hunter and 2 wildlife professionals with extensive histories of wild waterfowl and game bird exposure. Two laboratory methods showed evidence of past infection with influenza A/H11N9, a less common virus strain in wild ducks, in these 3 persons.
Wild ducks, geese, and shorebirds are the natural reservoir for influenza A virus (1); all 16 hemagglutinin (H) and 9 neuraminidase (N) subtypes are found in these wild birds (1,2). Recently, the rapid spread of influenza A/H5N1 virus to new geographic regions, possibly by migrating waterfowl, has caused concern among public health officials who fear an influenza pandemic. Until now, serologic studies of the transmission of subtype H5N1 and other highly pathogenic strains of avian influenza have focused on humans who have contact with infected domestic poultry (3,4). In this cross-sectional seroprevalence study, we provide evidence of past influenza A/H11 infection in persons who were routinely, heavily exposed to wild ducks and geese through recreational activities (duck hunting) or through their employment (bird banding). To our knowledge, this study is the first to show direct transmission of influenza A viruses from wild birds to humans.

The Study
In mid-October 2004, we enrolled 39 duck hunters who were hunting in southeastern Iowa at Lake Odessa Wildlife Management Area, the state's only limited-access public waterfowl hunting area managed by the Iowa Department of Natural Resources (DNR). In February 2005 we enrolled 68 Iowa DNR employees, many of whom had duck hunted or had been involved annually in capturing and banding wild ducks and geese as part of their duties of employment. Ten (15%) of the 68 DNR workers reported no contact with ducks. The duck-hunting group consisted of men >16 years of age, and the DNR group consisted of 65 men and 3 women enrollees. The average age of the duck hunters and DNR workers was 34 and 47 years, respectively. The average number of years of waterfowl or bird exposure of the duck hunters and DNR workers was 19.8 and 21.5, respectively. In the 3 years before the study, influenza vaccine had been administered to 37% of the duck hunters and 35% of the DNR workers.

Microneutralization assay, adapted per Rowe et al. (5), was performed on all serum samples with influenza A subtypes H1 through H12 from avian sources. Virus at 100 TCID50 (50% tissue culture infective dose)/50 μL was incubated at 37°C for 2 h with heat-inactivated serum in 96-well plates. One hundred microliters of trypsinized London MDCK cells at 2 × 105 cells/mL, grown to 70%–95% confluency, was added to each well. After 24 h at 37°C, the cells were acetone-fixed, and horseradish peroxidase–based ELISA was performed with mouse-specific anti-influenza A antibody. Optical density was read at 450 nm. All tested virus isolates were titrated with and without trypsin in the University of Iowa's Emerging Pathogens Laboratory; no significant difference in titers was observed. Backtiter controls were performed with each microneutralization assay.

Hemagglutination inhibition (HI) assay with horse erythrocytes, adapted per Meijer et al. (6), was performed on all hunter serum samples by using avian influenza A subtype H11. Heat-inactivated serum treated with receptor-destroying enzyme was first heme-adsorbed with packed horse erythrocytes. Serum was then incubated with virus at 8 hemagglutinin U/50 μL with 1% horse erythrocytes in 0.5% bovine serum albumin in phosphate-buffered saline for 1 h at room temperature in V-bottom plates. The plates were then examined.

One 39-year-old duck hunter had a titer of 40, and 2 male DNR workers, ages 52 and 53, had titers of 10 against influenza A/H11N9/duck/Memphis/546/76 by microneutralization assay (Table). These 3 study participants had substantial lifetime exposures to wild waterfowl. The duck hunter and the 2 DNR workers had 31, 27, and 30 years of duck-hunting experience, respectively. The duck hunter spent 25–60 days in the marsh each year hunting ducks. He harvested 100 ducks annually and handled another 300 ducks with his hunting partners during the duck-hunting season from mid-September to early December. One of the positive DNR workers (age 52) had several years of live wild duck–banding exposure as part of his annual duties of employment, in addition to 27 years of duck-hunting exposure. Each year this wildlife professional had contact with >100 live ducks during the banding season in late August and early September. Serum samples from all other study participants were negative against subtype H11N9 according to results of microneutralization assay and horse erythrocyte HI assays. The duck hunter's serum was not reactive to any other avian influenza hemagglutinin subtypes tested (H1–H10 and H12). The sera of the 2 H11-positive DNR workers had titers of 10 for influenza A/H2N2/mallard/NY/6750/78 according to microneutralization assay results and were negative for H1, H3–H10, and H12. Results of the H11 microneutralization assay were verified by horse erythrocyte HI assay that used subtype H11N9 virus. The titers by horse HI assay of the microneutralization assay–positive duck hunter and the 2 DNR workers were 10 or 20 (Table). These 3 study participants had not been vaccinated against influenza within 3 years before the study.

Table. Serologic results and demographics of duck hunter and Iowa DNR workers



Conclusions
Virus transmission from wild waterfowl to humans has not been documented. To our knowledge this study is the first to assess hunters with substantial exposures to wild ducks and geese, the known natural reservoir of influenza A virus in nature (1). During late August and early September in Iowa, when the banding of wild ducks occurs, and in mid-September, when duck hunting begins, a significant proportion of hatch-year mallards (up to 65%) and other ducks may be infected with influenza A virus according to other studies in North America (1,7). Later in the season, as the duck migration progresses, a decrease in prevalence is commonly seen (1,8). In late August 2004, we isolated influenza virus from mallards (60%) and from wood ducks (13%) in Iowa (data not shown).

Even though the H11-positive study participants had several years of exposure to wild birds infected with avian influenza virus through hunting and duck banding, they did not wear personal protective equipment, such as gloves, masks, or eye protection. These participants also did not use tobacco, a recently identified risk factor among swine facility workers with elevated serum antibodies against swine strains of influenza (9).
In this study we did not attempt to associate disease symptoms with exposure to wild waterfowl. Others have shown that domestic bird–acquired influenza A/H7N7 in humans may frequently lead to minor illness, such as conjunctivitis (4,10,11), although more serious disease has been recorded (4,10). We provide serologic evidence from 2 assays, microneutralization assay and horse erythrocyte HI, for past infection in humans with avian influenza A/H11 and no other avian influenza subtypes. Our findings are consistent with those of Beare and Webster (12), who reported a lack of antibody response in human volunteers inoculated with avian influenza strains with HA antigens wholly alien to humans. Those researchers did not inoculate volunteers with H11. In our study, a less common hemagglutinin subtype (H11) has apparently caused serologically detectable infections in high-exposure groups, whereas the more common hemagglutinin subtypes H4 and H6 (13–15) in wild ducks have not. The reason for this finding is unknown but may include the following: 1) H11 may have increased ability to infect humans, 2) H11 may provoke a relatively strong and detectable immune response, and 3) our serologic assays may be more sensitive in detecting H11 infection than other H subtypes.

Even though none of the H11-positive study participants had received influenza vaccine within the previous 3 years, the 2 positive DNR workers also showed reactivity by microneutralization assay to avian subtype H2N2. This result was not unexpected and likely represents reactivity from natural infection of the human H2N2 strain derived from avian sources that circulated from 1957 to 1967. Forty-one percent of participants of similar age (range 43–68 years, average 56 years) who grew up during the era of the human H2N2 pandemic also had positive test results. Except for the 2 H11N9-positive DNR workers, the other H2N2-positive study participants were nonreactive against avian subtype H11N9 (data not shown). This finding strengthens our conclusion that there was no cross-reactivity between H2N2 and H11N9 antisera. None of H11-positive study participants was reactive to avian subtypes H1 or H3, although others in the study population were. Only 7% and 18% of the study population were reactive by microneutralization assay against H1 and H3, respectively.

The relative lack of antibody response in our study population, who had substantial exposures to waterfowl with influenza A infections, and in inoculated volunteers from Beare and Webster (12) suggests that avian influenza infections in humans exposed to wild waterfowl may occur more commonly than we are able to detect with current methods. Although the sample size of our study was relatively small, our results suggest that handling wild waterfowl, especially ducks, is a risk factor for direct transmission of avian influenza virus to humans.

Acknowledgments
We thank Dale Garner, Bill Ohde, Guy Zenner, and other employees of the Iowa DNR for their assistance; the duck hunters who participated in this project; Sharon Setterquist, Mark Lebeck, Kelly Lesher, and Mohammad Ghazi for their technical assistance; and all volunteers who assisted with blood collecting.

This work was supported by grants from the University of Iowa Center for Health Effects of Environmental Contamination funds and the National Institutes of Allergy and Infectious Diseases (NIAID-R21 AI059214-01).

Dr Gill, in addition to providing emergency room duties as a physician, maintains an active research program as the zoonotic disease specialist at the University of Iowa Hygienic Laboratory. He recently codiscovered a new species of spotted fever group rickettsia and relapsing fever borrelia in the bat tick, Carios kelleyi. He also holds an adjunct position in the Department of Epidemiology in the College of Public Health at the University of Iowa.

References
Stallknecht DE, Shane SM. Host range of avian influenza virus in free-living birds. Vet Res Commun. 1988;12:125–41.
Fouchier RA, Munster V, Wallensten A, Bestebroer TM, Herfst S, Smith D, et al. Characterization of a novel influenza A virus hemagglutinin subtype (H16) obtained from black-headed gulls. J Virol. 2005;79:2814–22.
Bridges CB, Lim W, Hu-Primmer J, Sims L, Fukuda K, Mak KH, et al. Risk of influenza A (H5N1) infection among poultry workers, Hong Kong, 1997–1998. J Infect Dis. 2002;185:1005–10.
Koopmans M, Wilbrink B, Conyn M, Natrop G, van der Nat H, Vennema H, et al. Transmission of H7N7 avian influenza A virus to human beings during a large outbreak in commercial poultry farms in the Netherlands. Lancet. 2004;363:587–93.
Rowe T, Abernathy RA, Hu-Primmer J, Thompson WW, Lu X, Lim W, et al. Detection of antibody to avian influenza A (H5N1) virus in human serum by using a combination of serologic assays. J Clin Microbiol. 1999;37:937–43.
Meijer A, Bosman A, van de Kamp EE, Wilbrink B, van Beest Holle Mdu R, Koopmans M. Measurement of antibodies to avian influenza virus A (H7N7) in humans by hemagglutination inhibition test. J Virol Methods. 2006;132:113–20.
Hinshaw VS, Wood JM, Webster RG, Deibel R, Turner B. Circulation of influenza viruses and paramyxoviruses in waterfowl originating from two different areas in North America. Bull World Health Organ. 1985;63:711–9.
Stallknecht DE, Shane SM, Zwank PJ, Senne DA, Kearney MT. Avian influenza viruses from migratory and resident ducks of coastal Louisiana. Avian Dis. 1990;34:398–405.
Ramirez A, Capuano AW, Wellman DA, Lesher KA, Setterquist SF, Gray GC. Preventing zoonotic influenza infection. Emerg Infect Dis. 2006;12:997–1000.
Fouchier RA, Schneeberger PM, Rozendaal FW, Broekmen JM, Kemink SA, Munster V, et al. Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. Proc Natl Acad Sci U S A. 2004;101:1356–61.
Kurtz J, Manvell RJ, Banks J. Avian influenza virus isolated from a woman with conjunctivitis. Lancet. 1996;348:901–2.
Beare AS, Webster RG. Replication of avian influenza viruses in humans. Arch Virol. 1991:119:37–42.
Krauss S, Walker D, Pryor SP, Niles L, Chenghong L, Hinshaw VS, et al. Influenza A viruses of migrating wild aquatic birds in North America. Vector-Borne Zoonotic Dis. 2004;4:177–89.
Hanson BA, Stallknecht DE, Swayne DE, Lewis LA, Senne DA. Avian influenza viruses in Minnesota ducks during 1998–2000. Avian Dis. 2003; 47:867–71.
Slemons RD, Hansen WR, Converse KA, Senne DA. Type A influenza virus surveillance in free-flying, nonmigratory ducks residing on the eastern shore of Maryland. Avian Dis. 2003;47:1107–10.
Table
Table. Serologic results and demographics of duck hunter and Iowa DNR workers

Suggested Citation for this Article
Gill JS, Webby R, Gilchrist MJR, Gray GC. Avian influenza among waterfowl hunters and wildlife professionals. Emerg Infect Dis [serial on the Internet]. 2006 Aug [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol12no08/06-0492.htm

Is this important because of the U.S. connection?

How soon could we expect to see a formal statement from the federal government?

argyll wrote: How soon could we expect to see a formal statement from the federal government?

Do remember, I am only a medclinician putting up information which is accessable on the CDC website. There is a form at the link at the start of this thread where you may directly contact those involved in this study.

Medclinican,

medclinician wrote: To our knowledge, this study is the first to show direct transmission of influenza A viruses from wild birds to humans. This is a milestone event in terms of the beginnning of a Pandemic and yet not a single comment.

When I read this on the internet, my first thought is, that we have talked and talked about the fact that the virus must mutate in order to become easily transmissable. I think that the article suggests that the transmission from bird to Human maybe easier then we once thought. If other Avain virus can go directely from the host animal to the next host animal without mutating maybe H5N1 could also.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=112136

more tech data on H11N9 -

The HAs of the three H3N8 viruses were antigenically similar and were closely related to the HAs of the avian virus A/duck/Ukraine/1/63 (H3N8) and early human H3N2 influenza viruses (Fig. 1). Thus, the precursors of the pandemic human H3N2 influenza viruses continue to circulate in aquatic birds in southern China. Similarly, the HA of the H4N8 isolate was closely related antigenically to that of the prototype H4 influenza virus A/duck/Czech/56 (H4N6). The H6 hemagglutinins of the H6N1 and H6N9 viruses are antigenically similar to the prototype A/turkey/Mass/65 (H6N2) but could be distinguished from each other in the HI assay. The HAs of the five H11 influenza viruses are separable into two groups, H11N9 and others (H11N8 and H11N1). Each of the H11 isolates was distinguishable from the reference H11N6 strain A/duck/England/56. The HAs of the two H11N9 isolates show an antigenic similarity to that of the H11N1 isolate. These data show that a heterogeneous group of influenza A viruses were circulating in aquatic birds in the Hong Kong area during the time of the H5N1 outbreak. To characterize these virus isolates further, we performed sequence analysis of their internal genes. We analyzed these genes phylogenetically to determine the relationship between the isolates and to compare them with other influenza strains.

An H6N1 virus isolated from teal (A/teal/Hong Kong/W312/97 [H6N1]) showed very high (>98%) nucleotide homology to the human influenza virus A/Hong Kong/156/97 (H5N1) in the six internal genes. The N1 neuraminidase sequence showed 97% nucleotide homology to that of the human H5N1 virus, and the N1 protein of both viruses had the same 19-amino-acid deletion in the stalk region. The deduced hemagglutinin amino acid sequence of the H6N1 virus was most similar to that of A/shearwater/Australia/1/72 (H6N5). The H6N1 virus is the first known isolate with seven H5N1-like segments and may have been the donor of the neuraminidase and the internal genes of the H5N1 viruses.

Comment : As stated in other posts, there is a possibility that the presence of specific groups of HxNx viruses could illicit the formation of a human pathogenic strain. There has been considerable work done on the source and formation of both the SARS and H5N1 human HPAI. While H6N1 may likely be of greater odds to be a precursor, detection of H11N9 is difficult in humans and a far greater number carry this than previously suspected. Seeing is this is a direct transference from wild to human, this could set up an opportunistic enviroment for the next jump. Research on human infection with this strain is very scant.

Meat containing this virus is processed and considered safe for human consumption.

http://www.inspection.gc.ca/english/anima/heasan/disemala/avflu/2004sum/summaryhpaie.shtml

One flock of ducks, not reported in the Table of Infected Premises, tested positive for the H11N9 strain of avian influenza. These birds had been destined for slaughter for meat and were uncovered as a result of regular pre-slaughter surveillance. This finding was considered incidental to the outbreak; therefore, the ducks were slaughtered and their meat was processed for human consumption. Similarly, there was no regulatory action taken when a flock of geese were found to be serologically positive for the H6 strain of the virus.

Conclusion : Other strains of Avian which are being detected in human and are in poultry may come to present a serious problem. Several rogue types have evolved to become human pathogenic and more research into the other strains is indicated.

It is known that many bacteria and viruses are commonly found in humans and in those with adequate immune systems, sometimes produce no symptoms or sign of illness. However, birds may be infected, even with Hipath strains and show no symptoms as can humans.

Even in H5N1 human infection, some carriers are asymptomatic especially in the early phase of the disease and test negative in blood tests.

Since the risk of Pandemic looms before us, it is wise to further investigate other strains which we now consider harmless.

The 1918 is a grim reminder of what could happen if we do not.

Well I love to see all this research, and it is worthwhile to pay attention to authors' statements and conclusions.  The more you were to read about H11, which was the only avian virus the hunters had been exposed to, the more I think you would come to the conclusion that hunters so far have not been shown to be exposed to any avian flu from birds that is likely to be either highly pathogenic by itself, or capable of combining with H5N1.

response to one of medc's points:

We provide serologic evidence from 2 assays, microneutralization assay and horse erythrocyte HI, for past infection in humans with avian influenza A/H11 and no other avian influenza subtypes. Is this to say "they were infected but it wasn't a disease?" Or is this to say they had contracted a disease but were asymptomatic?

 

Infection [from Tabor's med. dict] is "presence and growth of a microorganism that produces tissue damage.  The extent of infection depends on the number and virulence of the organisms."

 

Disease is "a pathological condition that presents a group of clinical signs, symptoms, and laboratory findings..."

 

In serological testing for virus antibodies, the immune system could detect and kill all of the entering organisms and those detecting immune cells would still stimulate the immune system to prepare more for future attacks, as indicated for example by increased antibodies found on the serological testing.  It means there is an infection, but not necessarily the disease.   Since most people get flu-like symptoms often, they may not have even asked these subjects if they had flu-like symptoms in the last year because whether they did or not it would be almost impossible to determine which virus gave them those symptoms that they recall.

 

Serological presence of antibodies is just a clue about the past.  An example most are familiar with is TB skin testing.  A positive test shows that the person at some point was exposed to the bacilli.  It takes much more testing to figure out whether there were enough bacilli in their body to do any harm or to have need for treatment.

medclinician wrote: Dlugose wrote:   http://www.pubmedcentral.gov/articlerender.fcgi?artid=112136 Characterization of the Influenza A Virus Gene Pool in Avian Species in Southern China:  Was H6N1 a Derivative or a Precursor of H5N1? We found that two groups of viruses are circulating in the Hong Kong area. One group contains H9N2 and H6N1 viruses that are closely related to each other and to the H5N1 viruses in their internal genes. Therefore, it is likely that reassortment can occur within this group. The phylogenetic data suggest that the other subtypes (H3, H4, H11, etc.) are too far removed from the H5N1-like group to allow reassortment between the two groups. http://pubmedcentral.com/articlerender.fcgi?artid=135889 Reassortment between an amantadine-resistant variant of the human Singapore strain and amantadine-sensitive avian influenza A viruses. In a second set of experiments, MDCK cells were doubly infected with an amantadine-resistant variant of the human A/Singapore/57 (H2N2) (Singapore) strain... In addition to the A/Duck/Ukraine/63 (H3N8) virus, two HAs of recent isolates from Hong Kong, A/Duck/Hong Kong/Y264/97 (H4N8) and A/Duck/Hong Kong/P50/97 (H11N9), efficiently complemented the human Singapore strain Comment : Is this or is this not a mixture containing H11N9 which complements an Amantadine (first line defense of 4 anti-virals - used to combat H5N1 - is that correct?)

The title of this story really caught my eye. I wanted to post it along with the orginial that Medclincian posted. This seems to be an important story. How are the hunters doing?

Bird Flu Detected in Three People in Iowa, Study Finds Amitabh Avasthi for National Geographic News July 31, 2006 A duck hunter and two wildlife workers in Iowa have tested positive for a nonlethal form of avian flu, according to a team of U.S scientists. Their study is the first to suggest that bird flu can be transmitted to humans from wild birds. "We did not detect H5N1, the virus that has caused such a high death rate in the humans it has infected," said the study's lead author, James Gill, who is a disease specialist at the University of Iowa Hygienic Laboratory in Iowa City. Enlarge Photo Email to a Friend RELATED Flu Spread Is No Reason to Kill Wild Birds, Study Says Bird Flu: Frequently Asked Questions Photo Gallery: The Next Killer Flu Instead the researchers found that the infection was caused by the H11 virus, a strain commonly found in ducks, geese, and shorebirds but not previously associated with human illness. The study was conducted as part of ongoing surveillance efforts to track diseases that could be transmitted from animals to humans. (See National Geographic magazine's "Tracking the Next Killer Flu.") The research involved 39 duck hunters and 68 wildlife experts from the Iowa Department of Natural Resources. Their blood serum was tested for traces of antibodies against the influenza virus. Antibodies are signs of infection. "Our research found that one duck hunter and two of the wildlife professionals had been infected with the H11 virus, likely caught from wild waterfowl," Gill said. The findings appear in the August issue of the journal Emerging Infectious Diseases. Virus Mutated? It is still not clear what possible adaptations the H11 virus may have undergone to infect the human hosts or how exactly it may have spread to them. "We did not isolate the virus from the three infected persons. Our [test] was designed to detect antibodies in their blood," Gill said. Continued on Next Page >> LATEST VIDEOS IN THE NEWS Video: Dog Whisperer Tackles Pit Bull Terror Video: Night Diving off the Florida Keys Video: Hip-Hop Crosses Over to Cuba More Videos in the News SOURCES AND RELATED WEB SITES Emerging Infectious Diseases: Gill's Study Avian and pandemic flu information University of Iowa Hygienic Laboratory

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