A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>

Date: Mon 19 Sep 2011
Source: The Orange County Register [edited] <http://articles.ocregister.com/2011-09-19/news/30181585_1_dead-ducks-botulism-village-pond-park>

Mallards dying in Lake Forest lakes
In the last 2 weeks, more than 30 dead or dying ducks have been found at ponds and lakes around the city.

Residents of the Lake I and Lake II communities have reported finding hen and drake mallards floating in the lakes there and flopping on nearby grass. Dead ducks also have been found at Village Pond Park and nearby at the Forest Gardens Mobile Home Park. Officials from Orange County Animal Care have picked up some of the dead birds, and residents have tried to save some birds by taking them to the Wetlands & Wildlife Care Center in Huntington Beach.

A Lake I resident is concerned bread being fed to the ducks at Village Pond Park coupled with the recent heat and algae forming in the water are contributing to the growth of botulism.

"The city does no enforcement," [she] said of regulations prohibiting feeding ducks. "I've seen a baker's truck unload at the duck pond and people out there all day with non-duck food. It's very sad to see them just dying and flopping around."

[Byline: Erika I Ritchie]

Communicated by:
ProMED-mail from HealthMap alerts

[The photo in the original article at the source URL above shows a duck with a limp bent over neck. This is some times called "limberneck" and is another name for botulism. The conditions mentioned above may have contributed to this situation but it is impossible to comment on where the botulism came from with only the information in this article. However, if the dead bodies are not removed from the site, they continue to be part of the cycle. As maggots form in the carcasses they are filled with botulism. Those maggots are great bird food, as well as a source of more botulism.

Avian botulism is a paralytic disease caused by ingestion of a toxin produced by the bacteria _Clostridium botulinum_. These bacteria are widespread in soil and require 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 temperatures can provide ideal conditions for the botulism bacteria to activate and produce toxin. There are several types of toxin produced by strains of these bacteria; birds are most commonly affected by type C and to a lesser extent type E.

Birds either ingest the toxin directly or may eat invertebrates (such as chironomids [non-biting midges], fly larvae) containing the toxin.
Invertebrates are not affected by the toxin and store it in their body. A cycle develops in a botulism outbreak when fly larvae (maggots), feed on animal carcasses and ingest toxin. Ducks that consume toxin-laden maggots can develop botulism after eating as few as 3 or 4 maggots.

Healthy birds, affected birds, and dead birds in various stages of decay are commonly found in the same area. The toxin affects the nervous system by preventing impulse transmission to muscles. Birds are unable to use their wings and legs normally or control the 3rd eyelid, neck muscles, and other muscles. Birds with paralyzed neck muscles cannot hold their heads up and often drown (the disease has occasionally been called "limberneck"). Death can also result from water deprivation, electrolyte imbalance, respiratory failure, or predation.

Portions of this comment have been extracted from <http://www.nwhc.usgs.gov/disease_information/avian_botulism/>. - Mod.TG]

[A HealthMap/ProMED-mail interactive map of California can be seen at <http://healthmap.org/r/1h2c>. - Sr.Tech.Ed.MJ]

[see also:
Botulism, avian - USA: (CO) 20110914.2797 2010
Botulism, avian - USA (05): (FL) susp. 20100817.2848 Botulism, avian - USA (04): (OH) 20100718.2407 Botulism, avian - USA (03): (CA) 20100709.2294 Botulism - USA: canned tuna, risk, recall 20100708.2280 Botulism, avian - USA (02): (CO) 20100627.2145 Botulism, avian - USA: (MI) susp 20100618.2047] .................................................sb/tg/mj/ml/ll
ProMED-mail makes every effort to verify the reports that are posted, but the accuracy and completeness of the
information, and of any statements or opinions based
thereon, are not guaranteed. The reader assumes all risks in
using information posted or archived by ProMED-mail. ISID
and its associated service providers shall not be held responsible for errors or omissions or held liable for any damages incurred as a result of use or reliance upon posted or archived material.

Recent Activity:

Stay on top of your group activity without leaving the page you're on - Get the Yahoo! Toolbar now.




Post a Comment