This morning we have a report from yesterday's meeting of India's Monitoring Committee on Avian Influenza, with additional details on the testing results for the H5N8 virus - particularly from the National Zoological Park in New Delhi.
According to recent press reports, India's testing laboratories are backlogged with with thousands of samples yet to process, prompting yesterday's media report Bird flu: Centre asks NIHSAD to expedite testing of samples.
But in today's report we get a smattering of test results, including positive tests on several species and for pond water and mud around Pelican Pond, a popular stopover for migratory birds located within the National Zoological Park.
First the report, then I'll return with a bit more.
Press Information Bureau
Government of India
Ministry of Environment and Forests
28-October-2016 20:38 IST
Report of the Monitoring Committee on Avian Influenza
The Monitoring Committee constituted by the Ministry of Environment, Forest and Climate Change for overseeing the outbreak of avian influenza reviewed the control and containment of the avian influenza situation today.
Mortality Status within 24 hours:
NATIONAL ZOOLOGICAL PARK, NEW DELHI - Nil
DEER PARK, HAUZ KHAS, NEW DELHI - Nil
GWALIOR ZOO - Nil
The control and containment measures of avian influenza in the affected zoos are being continued, which include:
1. Surveillance continues and the zoo is being screened regularly for any dead bird.
2. Bio-security measures being strictly enforced.
3. Zoo remained closed for the safety of visitors and control of the disease.
4. A medical doctor visited and examined exposed employees of the zoo and medication was provided.
5. Report from ICAR National Institute of High Security Animal Diseases indicating updated interim results of samples sent on 22.10.2016 from National Zoological Park is enclosed. The results are as under:
6. Review meeting was held under the Chairmanship of Animal Husbandry Commissioner on 27.10.2016 wherein the report was discussed.
7. It was decided to put on hold the culling operations for the time being in the infected zone.
8. Anti-viral solution is being sprayed on the affected mud near Pelican Island to prevent further infection.
9. The water from Pelican Pond has also been tested positive for H5N8. The issue was discussed in the meeting and it was decided that treatment of water body by chemical such as bleaching powder, or lime, will not be feasible as it will adversely affect the aquatic life of the water body.
The lack of reported bird deaths in the past 24 hours at the three zoos listed is a good sign, but the detection of the virus in the zoo's environment suggests that additional birds could still be infected.
Avian influenza is gastrointestinal infection in birds, and they shed the virus through their feces - which can easily contaminate fresh water sources.
Previous tests conducted on other HPAI and LPAI avian viruses (including H5N1) have shown prolonged persistence in the environment (see H5N1: Hiding In Plain Sight and EID Journal: Persistence Of H5N1 In Soil), remaining viable for days or even weeks depending upon conditions.
Another finding of note is the positive test result on a Crow.
While waterfowl (ducks & geese) and gallinaceous birds (turkeys, grouse, chickens & quail) are most often associated with carriage of HPAI H5 viruses, terrestrial birds such as crows, starlings, pigeons, and sparrows are also known to carry, and shed, theses viruses as well (see 2007’s EID Journal Role of Terrestrial Wild Birds in Ecology of Influenza A Virus (H5N1).
As far back as 2008, we saw reports out of India of crows dying from the H5N1 virus. In 2012, and again in 2014 India saw numerous wild bird die offs that were blamed on the avian flu virus (see Media Report: H5N1 Killing Crows In Jharkhand).
Although the incidence of terrestrial bird carriage of HPAI viruses is poorly understood and its significance remains hotly debated, recent studies and surveillance suggests their role may be greater than previously believed.
- The Survey of H5N1 Flu Virus in Wild Birds in 14 Provinces of China from 2004 to 2007, published in 2009, found 26 positive samples distributed across 9 species from among 7320 passerine samples tested, providing a very low incidence of 0.36%. However, among tree sparrows tested, the prevalence was three times higher at 1.09%.
- The 2012 PLoS One Study A Survey of Avian Influenza in Tree Sparrows in China in 2011, found serological evidence of prior H5 subtype HPAI infection in 94 of 800 (11.75%) of sparrows tested, showing that HPAI H5 infection need not always prove fatal in that species.
- In 2013, in Pathogenesis in Eurasian tree sparrows inoculated with H5N1 highly pathogenic avian influenza virus and experimental virus transmission from tree sparrows to chickens by Yamamoto Y, Nakamura K, Yamada M, Mase M., the authors found that inoculated birds lived up to 11 days and shed copious amounts of the virus during that time, and suggested that Eurasian tree sparrows could be potential vectors to housed poultry.
- And a 2015 study - Avian Path: Susceptibility of Wild Passerine Birds To HPAI H5N1 - examined the susceptibility of three passerine bird species (reed buntings, brown-eared bulbuls and pale thrushes) to HPAI H5N1, and finds that 2 out of 3 (buntings & bulbuls) sickened and died, while pale thrushes seroconverted exhibited no clinical signs of infection.
Although there are media reports of other Indian States awaiting test results, as of this writing no new outbreaks have been confirmed.