waterfowl diseases update – past 15 years nicole beaver

Avian CholeraAvian Cholera

Most important disease in N. Most important disease in N. American waterfowlAmerican waterfowl

Kills quickly – 6-12 hoursKills quickly – 6-12 hours First diagnosed in 1940First diagnosed in 1940 Outbreaks in new areas have Outbreaks in new areas have

become more frequent in the past 20 become more frequent in the past 20 yearsyears

Avian Cholera – Recent Avian Cholera – Recent ResearchResearch

Little is known about the Little is known about the interactions between the host, the interactions between the host, the agent, and the environmentagent, and the environment

Outbreaks tend to occur in Outbreaks tend to occur in wetlands/populations that have wetlands/populations that have suffered previous outbreakssuffered previous outbreaks

Agent could survive in infected Agent could survive in infected wetland OR in carriers birdswetland OR in carriers birds

Recent Research cont.Recent Research cont.

Sacramento National Wildlife RefugeSacramento National Wildlife Refuge Water and sediments tested for Water and sediments tested for

Pasteurella multocidaPasteurella multocida The bacteria was found in samples taken The bacteria was found in samples taken

during or soon after outbreaksduring or soon after outbreaks Samples 1-3 months post-outbreak did not Samples 1-3 months post-outbreak did not

contain the bacteriacontain the bacteria P. multocida P. multocida probably doesn’t survive probably doesn’t survive

long enough in the environment to long enough in the environment to cause the recurring outbreakscause the recurring outbreaks

Recent Research cont.Recent Research cont.

Carrier birdsCarrier birds Lesser snow geese from Wrangle Island, Lesser snow geese from Wrangle Island,

Russia and Banks Island, CanadaRussia and Banks Island, Canada Blood samples collected each summer and Blood samples collected each summer and

tested for antibodiestested for antibodies 8% of blood samples from the Banks Island pop. 8% of blood samples from the Banks Island pop.

Contained antibodies (post-outbreak)Contained antibodies (post-outbreak) 3% with antibody from Wrangle Island (no outbreak)3% with antibody from Wrangle Island (no outbreak)

More birds infected than once thoughMore birds infected than once though Some survive infection – could become carriersSome survive infection – could become carriers More research is neededMore research is needed

Avian BotulismAvian Botulism

Botulism has occurred naturally for Botulism has occurred naturally for centuries, however, changes in habitat use centuries, however, changes in habitat use may be increasing the severity of may be increasing the severity of outbreaksoutbreaks

Cleaning up carcasses is not completely Cleaning up carcasses is not completely effectiveeffective More birds die than can be found and removedMore birds die than can be found and removed Money going toward cleanups could be better Money going toward cleanups could be better

spent in more research, or in conserving more spent in more research, or in conserving more wetland habitatwetland habitat

Botulism - ResearchBotulism - Research

Connection between botulism and Connection between botulism and blue-green algae bloomsblue-green algae blooms

Describe water quality and weather Describe water quality and weather during botulism outbreaksduring botulism outbreaks

Increase understanding of carcass-Increase understanding of carcass-maggot cycles and identify other maggot cycles and identify other possible carrierspossible carriers

Duck Virus EntiritisDuck Virus Entiritis

1993 outbreak in Finger Lakes, New 1993 outbreak in Finger Lakes, New YorkYork

Some exposed birds become carriersSome exposed birds become carriers Appear healthy but can transmit the Appear healthy but can transmit the

disease to othersdisease to others A vaccine does exist, but is used A vaccine does exist, but is used

primarily in breeder ducksprimarily in breeder ducks

West Nile VirusWest Nile Virus New York City New York City

area – 1999area – 1999 Spread through Spread through

U.S., Canada, U.S., Canada, Mexico, and Mexico, and CaribbeanCaribbean

FlavivirusFlavivirus Transmitted by Transmitted by

mosquitoesmosquitoes Affects about 250 Affects about 250

species of bird species of bird

Symptoms of WNVSymptoms of WNV

WeaknessWeakness Stumbling/tremblingStumbling/trembling Head tremorsHead tremors Can’t flyCan’t fly Easily approachableEasily approachable

West Nile VirusWest Nile Virus

WNV ControlWNV Control

Mainly aimed at preventionMainly aimed at prevention Mosquito controlMosquito control

Public reports of dead birdsPublic reports of dead birds

Avian Vacuolar Avian Vacuolar Myelinopathy (AVM)Myelinopathy (AVM)

Recently discovered Recently discovered neurological diseaseneurological disease

Mainly affects bald Mainly affects bald eagles and American eagles and American coots coots Also confirmed in Also confirmed in

mallards, buffleheads, mallards, buffleheads, ring-necked ducks, and ring-necked ducks, and Canada geeseCanada geese

Occurs from November Occurs from November to March as populations to March as populations migrate in and out of migrate in and out of areasareas

Arkansas, Georgia, N. Arkansas, Georgia, N. and S. Carolina, and S. Carolina, suspected in Texassuspected in Texas

AVM SymptomsAVM Symptoms Lack of muscle Lack of muscle

controlcontrol Fly into walls, crash-Fly into walls, crash-

land, appear land, appear intoxicated, swim intoxicated, swim upside-downupside-down

Affected birds appear Affected birds appear healthy and are alert healthy and are alert and aware of and aware of surroundingssurroundings

Lesions in myelin of Lesions in myelin of brain and spinal cordbrain and spinal cord

CauseCause

UnknownUnknown Not parasitic, fungal, bacterial, viral, Not parasitic, fungal, bacterial, viral,

or prionor prion Associated with submerged aquatic Associated with submerged aquatic

vegetationvegetation Onset is dose-dependentOnset is dose-dependent Suspect cause is a toxin – natural or Suspect cause is a toxin – natural or

man-mademan-made

ResearchResearch

Exposure is site specific and seasonal.Exposure is site specific and seasonal. Birds with brain lesions may not Birds with brain lesions may not

exhibit symptoms.exhibit symptoms. Brain lesions were produced in red-Brain lesions were produced in red-

tailed hawks in laboratory conditions tailed hawks in laboratory conditions when fed tissue from affected coots.when fed tissue from affected coots.

An invasive aquatic plant, hydrilla, An invasive aquatic plant, hydrilla, produced brain legions in some produced brain legions in some laboratory mallards.laboratory mallards.

AVM – Future ResearchAVM – Future Research Continue to monitor AVM at lakes where Continue to monitor AVM at lakes where

the disease occurs and at nearby lakes the disease occurs and at nearby lakes without disease. without disease.

Characterize environmental factors at the Characterize environmental factors at the sites where AVM has occurred. These site sites where AVM has occurred. These site characterizations will be instrumental for characterizations will be instrumental for developing risk assessment models and may developing risk assessment models and may generate hypotheses regarding generate hypotheses regarding environmental conditions conducive for environmental conditions conducive for AVM outbreaks. AVM outbreaks.

Identify the causative agent of AVM. Identify the causative agent of AVM.

Avian InfluenzaAvian Influenza

Virus which spreads through contact Virus which spreads through contact with feces, saliva, or nasal dischargewith feces, saliva, or nasal discharge

Mainly found in poultry and wild Mainly found in poultry and wild birds (including some waterfowl), birds (including some waterfowl), but can affect mammals as wellbut can affect mammals as well

When the virus jumps species, it When the virus jumps species, it mutatesmutates

SymptomsSymptoms

Low pathogenic forms are often Low pathogenic forms are often undetectedundetected

Symptoms may be as slight as ruffled Symptoms may be as slight as ruffled feathers and a small decrease in egg feathers and a small decrease in egg productionproduction

Highly pathogenic forms can affect Highly pathogenic forms can affect multiple internal organsmultiple internal organs 90-100% mortality90-100% mortality 48 hour incubation48 hour incubation

Avian InfluenzaAvian Influenza

Low or highly pathogenicLow or highly pathogenic Depends on strainDepends on strain

Strain H5N1 is highly pathogenicStrain H5N1 is highly pathogenic Mortality in more than 80 bird speciesMortality in more than 80 bird species 98 human fatalities98 human fatalities

Low pathogenic forms have occurred Low pathogenic forms have occurred in North Americain North America

Peak occurrence in N. American Peak occurrence in N. American ducks is late summer and early fallducks is late summer and early fall

H5N1H5N1

Highly contagious among birdsHighly contagious among birds Does not usually spread to humansDoes not usually spread to humans Close contact with infected birdsClose contact with infected birds

ControlControl Ban on birds and bird products from Ban on birds and bird products from

affected countriesaffected countries

Current SituationCurrent Situation

The outbreak is not expected to The outbreak is not expected to diminish in affected areasdiminish in affected areas

Ducks are shedding more virus for Ducks are shedding more virus for longer periods of time, without longer periods of time, without showing signs of the illnessshowing signs of the illness

There is little natural immunity to There is little natural immunity to this strain among humansthis strain among humans

waterfowl diseases update – past 15 years nicole beaver

Documents

wrangle island

outbreakmore birds

effectivemore birds

carriersmore research

banks island pop

new yorksome exposed

swim upsidedownaffected

canadablood samples