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Florida’s Wetlands and Wildlife HealthMarilyn G. Spalding, Department of Infectious Diseases and Pathology, College of

Veterinary Medicine, University of Florida, Gainesville, Florida

Aquatic birds• Loons and grebes• Tubenoses• Pelicaniformes• Anhingas and cormorants• Wading birds• Swans and geese• Ducks• Raptors• Cranes• Shorebirds

• Terns• Alcids• Kingfishers• Dippers

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Black Skimmer, Photo Image # BLSK 177What a fascinating and graceful bird to watch, asthis photo shows an adult Black Skimmer flyingwith its knife-edged lower mandible submergedin the water. When this Black Skimmer feels

something in the water when it's skimming, it willsnap its head down and hopefully clamp onto a

fish.Return to Birds of the Wetlands

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Florida’s Wetlands and Wildlife HealthMarilyn G. Spalding, Department of Infectious Diseases and Pathology, College of

Veterinary Medicine, University of Florida, Gainesville, Florida

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ANIMALHEALTH

DISEASE AGENT ENVIRONMENT

HOST

ANIMALHEALTH

DISEASE AGENT

ENVIRONMENTALALTERATION

HOST

ENVIRONMENT

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CHANGES IN ENVIRONMENT

•TOXIN CONTAMINATION - mercury, antibiotics, pesticides,immunosupression•NUTRIENT CONTAMINATION – eustrongylidiosis, AVM?, Redtide?

•ATTRACTIVE NUSIANCE – eustrongylidosis, spray fields, landfills,

•CHANGE FOOD RESOURCES – peanut toxicosis, Newcastle disease, aviancholera, immunosupression

•TRANSLOCATE ANIMALS and/or PATHOGENS – WNV, HPAI, SARS

• STRUCTURAL HAZARDS – powerlines, roads, boat use, vehicles, etc.

•LOSS OR ALTERATION OF WETLANDS- resulting in:Crowding,Relocation, Diet change, nesting habitat loss, exposure to

new species, habitats- HPAI, EEE, SARS

Contaminants in water

• Nutrients• Methyl Mercury• Chlorinated hydrocarbons, PCB,s, Dioxins,• Sodium chloride• Antibiotics• Estrogen

Current Exposure in Everglades

• ↓ PCV• ↓ Lymphoid tissue• ↓ Appetite/Motivation to hunt• ↓ Weight• Changes in tissue enzymes• Thermoregulation change• Lethargy• Decreased immune function

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Trauma Chronic disease

Great White Heron fledglings -cause of mortality

Spalding et al. 1994

Nutrient contaminants

• Eustrongylidosis, and other parasites• Biotoxins? – red tide, botulism• Attractive nuisance

Eustrongylidosis•Nematode parasiteof herons andcormorants•Complex life cycle

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Eustrongylides ignotus

+nutrients

Contaminant:nutrients(sewage)Attractivenuisance

Eustrongylidosis•Cycle driven byaddition of nutrientsto water•Kills up to 80% ofyoung birds in nest

Infectious diseases

• Fecal contamination, Escherichia coli,Campylobacter, Salmonella, Shigella

• Avian cholera• Salmonellosis• Newcastle Disease – aquaculture/cormorants• Avian influenza

– Most benign, HPAI

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Avian influenza A•Waterbirds are natural reservoirs.Asymptomatic birds are frequently infectedwith multiple strains of virus.•Transmission fecal oral/contamination ofwater

Domestic-wildspecies contact

MigrationTransportation

of products

High pathogenic avian influenza•High pathogenic avian influenza (rare) may betransmitted to wild birds by contact with domesticducks and chickens and their waste and vise versa•Spread by chicken products and/or wild birdmigration•Fatal disease in wild birds,chickens, waterbirds,mammals, and humans

Newcastle disease•Highly contagious viral enteric or neurologicdisease•Transmission by aerosol or fecal ingestion•Transported by carrier birds•Causes reduced eggproduction to rapid death

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Aquaculture-increased

populationdensity

Migration

Newcastle disease virus•Access to abundant food(catfish and crayfishaquaculture) in gulf statesincreases population size•Increased colony size andexposure of nestlings to virus•Mortality especially of young birds•Adult carrier birds arethreat to poultryindustry

Biotoxins

• Avian vacuolar myelinopathy?• Botulism• Red tide• Domoic acid• Other harmful algal biotoxins (HAB’s)• Mycotoxins

Avian vacuolar myelinopathy (AVM)•Unidentified toxin biotoxin producesdisorientation and brain lesions in coots andeagles at certain lakes in the southeast•Recent “emerging” disease

T. Augspurger, USFWS

Whaleimages.com

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Exoticweed,

nutrientpollution,

Toxin?

Avian vacuolar myelinopathy (AVM)•Aquatic nutrient pollutionincreases mats of highlyinvasive exotic Hydrillawhich harbors a toxinproducing organism•Coots ingesting Hydrillabecome disoriented andare eaten by eagles

?

T. Augspurger, USFWS

Whaleimages.com

Translocation of pathogen/host

• West Nile Virus• Malaria

West Nile Virus• Example of translocation of a disease• Common in Eurasia with occasional outbreaks, rare bird

mortality• Transmitted by mosquitoes• Entered North America for first time in 1999 causing over 500

human deaths• Extensive mortality insome bird species especiallyCorvids and hawks• With time, immunitydevelops, similar to Europe

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Wetland loss – crowding

• Increased exposure to sick birds– Ie avian cholera

• Exposure to novel species (and their diseases)• Increase chance of dead bird starting botulism epizootic• Decrease in water quality

– Fecal contamination – clostridium, salmonella

•Very rapidly reproducingbacteria: Pasteurella multocida•Fecal contamination of waterwhich is aerosolized when birdstake off from water

Avian cholera

Fewer wetlands,

Artificial foodresources,

Avian cholera•Access to waste grainincreases population size•Immune suppression may beassociated with Vit A deficientcorn diet•Fewer wetlands availablefurther increases density•Fecal contamination ofwetlands•Rapid death of 10,000’s ofbirds every year

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Water associated hazards• Fish hooks, lead sinkers, monofilament• Powerlines, towers, roads and bridges• Trash

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Wetland loss – impact onreproduction

• Increased predation – adult and chickmortality

• Decreased habitat quality – foraging andnesting

• Decreased pair experience

Florida 2060: A Research Project of 1000 Friends of Florida

2060 Developed Lands and Permanent Conservation Lands

Developed Land

Conservation LandsPermanently Protected

Reproductive health

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• Decreased quality habitat for foraging and nesting• Forces use of marginal habitats with associated

danger– increase hazards, especially boats

• Increases territorial competition– Increases adult and chick mortality– Increased exposure to terrestrial predators– Decreases pair “experience level”

Wetland loss: development,drainage, drought

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REPROINDEX

WINTERWELL REPROINDEX

Whooping cranereproduction in Florida

Wildlife health

• Wildlife health is closely tied to environmentalchanges

• Environmental changes are more often thannot made by humans

• So animal health issues are of vital concern tous.

• And these issues need to be considered whenplanning changes or solutions

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• Crowding from wetland loss, development, drainage, drought• Population expansion and inadequate nutrition from agriculture and

aquaculture food availability• Pathogen exposure and nutrient pollution from human and animal waste• Movement of host and disease agents• Toxins –physiologic change and immune suppression

Emerging disease? or new opportunities?

Suggested action items• Include wildlife health issues

in the planning and regulatorystages of development

• Preserve wetlands to preventcrowding and increaseddisease transmission

• Separate human sewage anddomestic animal waste fromwildlife access

• Control access toaqua/agricultural food surplus

• Prevent aquatic nutrient andtoxin contamination

• Limit wildlife access tophysical hazards