Dubai: Residents' fears from seeing dead gulls near the Lake at International City can cease, according to a Dubai-based zoologist and bird expert, as this is due to some bacterial disease that affects gulls and other birds.
According to Dr Reza Khan, a wildlife specialist at Dubai Zoo, there are between 5,000 and 10,000 gulls flying from the Dubai Sewage Treatment Plant and the Lake at International City.
Gulls have a few places between which to move in the area and depend on food thrown away or dead plants and animals, which can cause botulism, a bacterial disease associated with birds.
Botulism
Avian botulism causes paralysis resulting from ingestion of a toxin produced by the bacteria, Clostridium botulinum. This bacteria are widespread in soil and requires warm temperatures, a protein source and an anaerobic (no oxygen) environment in order to become active and produce toxin.
Decomposing vegetation and invertebrates combined with warm temperature can provide ideal conditions for the bacteria to activate and produce toxin. There are several types of toxins produced by strains of this bacteria; birds are most commonly affected by type C and to a lesser extent by type E.
According to the Zoological Society of London, botulism causes considerable mortality in gulls in the UK, and landfills are suspected as a major source of the toxin. The bacteria were found in 12 of 19 landfill sites examined.
"The presence of these spores, together with the rotting organic matter and generated heat associated with landfill sites, undoubtedly leads to bacterial proliferation and toxigenesis," states a report by the Society. "This is likely to result in botulism in scavenging gulls unless skilled landfill management prevents the ingestion of toxic material."
Khan yesterday said that a small number of Gulls from a flock of 10,000 feeding on waste material in the area is quite natural. "Dead animals and plants are part of their normal diet, they are depending on these for food, and in return suffer from botulism," he said.
Birds either ingest the toxin directly or may eat prey containing the toxin. Fajis Abu Bakr, a Gulf News reader had sent a community report published on January 29 about the dead birds in International City.
