Wildlife Flashcards
What are the major wildlife diseases of importance (9)?
- Rabies
- Canine distemper
- Hemorrhagic disease
- Chronic wasting disease
- White nose syndrome of bats
- Avian pox
- Duck plague
- Avian influenza
- Avian cholera
What accounts for the largest proportion of human cases of rabies?
Bat exposures
What animal in VA is most frequently reported for rabies?
Raccoon
Describe the etiology, host, and transmission of canine distemper virus in wildlife.
- Etiology: morbillivirus, epitheliotropic and attacks epithelial cells of the repsiratory tract, GIT and eyes
- Host: cause of mortality in raccoons, gray foxes, and coyotes
- Transmission: direct contact, aerosol of ocular and nasal secretions, urine - does not survive in the environment
Describe the etiology, host, and transmission of hemorrhagic disease in wildlife.
- Etiology: 2 closerly related but distinct orbiviruses - epizootic hemorrhagic disease (EHD) and bluetognue virus (BT)
- Host: most important infectious diseae of white-tailed deer in southeastern US
- Transmission: biting midges (culicoides)
Describe how deer are often found in the wild when infected with hemorrhagic disease.
- Late summer to early fall
- Recumbent and close to a source of water
Signficance of canine distemper in wildlife
Mot major human public health concern
Significance of hemorrhagic disease in wildlife
- Can cause dramatic local population declines in white-tailed deer
- Can resemble FMD, rinderpest, and heartwater in deer and livestock
- No public health significance
Describe the etiology, host, and transmission of chronic wasting disease in wildlife.
- Etiology: prions - transmissible spongiform encephalopathy, resulting in spongiform degeneration of CNS (interneuronal vacuoles)
- Host: white-tailed deer, elk, mule deer, black-tailed deer, and moose
- Transmission: direct froma animal to animal, indirect fro contaminated food of environment (importance unkown)
How is CWD diagnosed?
Examination of the obex of medulla oblongata and retropharyngeal lymph nodes for the presence of prions (post-mortem)
CWD significance
- No scientific evidence it has infected humans
- No correleation to CJD
Describe the etiology, host, and transmission of white nose syndrom in bats.
- Etiology: fungus pseudogymnoascus (geomyces) destructans, which thrives in the characteristics of most bat habitats, cannot grow above 20C = 68F like most fungi
- Host: 9 species of bats (little brown, big brown, northern-long eared, eastern pipistrelle, indianda, gray bat)
- Transmission: ??
Describe the etiology, host, and transmission of rabbit hemorrhagic disease.
- Etiology: lagovirus (calicivirdae) RHDV1 = adults, no resevoir in NA, RHDV2 = multiple species of rabbits, lower mortality than 1
- Host: rabbits and hares (2) or adult rabbits oryctolagus cuniculus (1)
- Transmission: ??
Describe the etiology, host, and transmission of avian pox.
- Etiology: pox virus
- Host: birds
- Transmission: blood-feeding insects (mosquitoes), inhalation or ingestion of virus-laden scabs
- No public health risk
Describe the control methods of avian pox in the wild and in captivity.
Wild - eliminate mosquito breeding sites, mosquito larvacides and adulticides
Captive - disinfection of equiptment w 5% bleach, screening, MLV in domestic birds
Describe the etiology, host, and transmission of duck plague.
- Etiology: duck viral enteritis caused by herpesvirus
- Host: only ducks, swans, and geese (Anseriformes)
- Transmission: infected waterfowl or environment, virus sheds in fecal/oral discharges, survivors become lifetime carriers and shed virus
Describe control and prevention measures of duck plague.
- Control - destruction of infected flocks/eggs, carcass disposal via incineration, decontamination of environment, disinfection of equiptment
- Prevention - attenuated vx approved for domestic ducks only
- No public health risk
Describe the etiology, host, and transmission of avian influenza.
- Etiology: orthomyxovirus, H5 and H7 most common HPAI, LPAI not reportable
- Host: domestic poultry, waterfowl, other wild birds
- Transmission: horizontal, migratory waterfowl wild resevoirs but transmission to poultry unlikely, virus shed in feces and secretions, spread by contaminated feed and water equiptment, vehicles, and people
Describe prevention and control measures for avian influenza.
- Report to state vet
- Depopulation
- Inactivation via heat, dryness, pH extremes
- Disinfect with bleach, virkon, phenol, or formalin
Describe the etiology, host, and transmission of avian cholera.
Etiology: pasteurella multocida
Host: water birds, some rodent species and raptors as well
Transmission: infected birds shedding bacteria, infected carcasses, chronic carriers, seasonal in winter
Describe control/prevention measures of avian cholera.
Control - dispoasal and incineration of infected carcasses, habitat management, disinfection, vaccination of captive flocks (bacterin)
What are the prevention/control measures used for rabies?
- Vaccination for domestic animals = buffer zone between humans and wildlife
- Oral vaccine for free-ranging carnivores that consume vaccine-laden baits (racoons, coyotes)
Canine distemper clinical signs in wildlife
Respiratory, GI, neurologic (similar to rabies), and proliferation of foot pad epithelium
Clinical signs of hemorrhagic disease in wildlife
- Fever, depression, oral ctanosis
- Pulmonary edema, hemorrhage at base of pulmonary artery
- Edema of head, neck, tongue and conjunctiva
- Sloughing of hoof, rumen ulcers and loss of rumen papillae
- Death 1-3 days
Clinical signs of white-nosed syndrome in bats.
- Iritation = bats dont hibernate = no food = weight loss
- Microscopic fungal hyphae on external surfaces
Clinical signs of avian pox
- Visual impairement, resp distress, weakness and emaciation
- Dry = cutaneous - proliferative nodules of unfeathered areas like the nares
- Wet = dipthertic - raised plaques in oral cavity or resp tract
Clinical signs of duck plague
- Blood discharge from nares, mouth, or vent
- Prolapsed phallus
- Inability to fly
- Convulsions, death
- Hemorrhages on heart and liver
- Raised necrotic plaques or ulcerations of intestines
Clinical signs of avian cholera
- Incoordination, tremors
- Inability to fly
- Sudden death
- Hemorrhages in heart, gizzard and liver
- Multifocal hepatic necrosis
- Copper-colored liver
What are the important zoonotic diseases of wildlife (6)?
- Hanta virus
- Plague
- Tularemia
- Mycobacteriosis (deer)
- Mycobacteriosis (avian)
- West Nile Virus
Describe the etiology, host, location, and transmission of hantavirus.
- Etiology: Bunyavirdae virus
- Location: Western USA (national park cabins)
- Host: Rodents are primary resevour (deer mouse SW, cotton rate SE, white-footed mouse) –> usually show no clinical signs
- Transmission: virus particles become aerosolized from rodent urine, feces, or saliva and are inhaled or through handling rodents (think cleaning infested places)
Describe the control of hantavirus.
- Rodent control
- Sanitation
- Safety percautions including use of protective equiptment
Describe the etiology, host, location, and transmission of tularemia.
Etiology: francisella tularenesis (g-)
Location: central US
Host: terrestrial cycle involved rabbits and rodents, aquatic cycle involves muskrats and beavers.
Transmission: blood-sucking arthropods, ingestion, inhalation, direct contact through skin, contamination of wounds
Describe the clinical signs of tularemia in rabbits.
- Lethargy, incoordination, occasional mortality
- Pinpoint white lesions in liver and spleen
Prevention of zoonotic tularemia?
- Sanitary precautions
- Wear gloves
- Control insect vectors
Describe the etiology, host, location, and transmission of the plague.
- Etiology: yersinia pestis (g-)
- Location: Western US
- Host: flea-rodent cycle, resevoirs are voles, grasshopper mice, and rock squirrels….also prarier dogs and ground squirrels….felids and black-footed ferret suceptible
- Transmission: flea bite! –> multiplies in GIT, regurgitation of blood into host
What are the prevention/control measures for the plague?
- Insecticides of environment
- Local control of rodents close to humans
- Must kill fleas
- Treat all pets for flease
- Protective clothing
- Restriciton of outdor activites in areas with active plauge
What are the public health concenrs of the plauge?
Category A bioterrorism agent
Describe the etiology, host, location, and transmission of tuberculosis in deer.
- Etiology: M. bovis
- Location: north, great lakes? minnesota?
- Host: Northern deer populations
- Transmission: aerosol, consumption of contaminated feed, close contract with infected individual or contaminated area, enhanced by crowing and stress, people feeding deer in winter!!!
What are the clinical signs of tuberculosis in deer?
- Chronic , weight loss
- Yellow to tan pea-sized nodules in chest cavity or lungs
- SQ swelling/abscess
- Swollen lnn in head and cranial neck region
What are prevention/control measures for zoonotic tuberculosis in deers?
- Reduce deer density through huntring
- Keep deer from concentration by eliminating supplemental feeding and baiting
- Wear protective clothing and gloves when field dressing deer
Significance of TB in deer?
- Loss of bovine TB free-status and trade
- Hunters exposed
Describe the etiology, host, location, and transmission of avian tuberculosis.
- Etiology: mycobacterium avium
- Location: ?
- Host: birds
- Transmission: fecal contamination, ingestion of contaminated food/water/environment, waste water and sewage effluents, long-term spore survival in soilt, migratory bird concentrations
What are the clinical signs of avian Tb in birds?
- Emaciation, muscle wasting, weakness, occasional diarrhea, lameness, dull plumage…chronic progessive multisystemic disease
- Multifocal granulomatous nodules in lung and air scas, liver spleen intestines and gonads as well
What are control/prevention measures for avian Tb? Whos at risk?
- Ante-mortem testing and environmental decontamination are both very difficult
- Immunoincompetent individuals at risk
Describe the etiology, host, location, and transmission of West Nile Virus.
- Etiology: arthropod-borne virus
- Location: central US
- Host: corvids, raptors, wild bird species, zoo/captive birds like pengiuns, horses, people, deer, black bear = dead-end hosts
- Transmission: vectors = mosquitoes, soft and hard ticks, hippoboscid flies, possible bird to bird (only experimentally)
What are prevention/control measures for west nile virus?
Insect repellents
Environmental larvacides and adulticides
How do humans get toxoplasma?
- Exposure with oocysts
- Contaminated soil around homes, in vegetable gardens
- Runoff containing oocysts –> rivers and oceans –> filter feeding shellfish
How do veterinarians get exposed to toxoplasma?
- Tissue cysts –> necropsy of infected animals
- Handling aborted fetuses/placental membranes
- Any felids
How do humans get cryptosporidium parvum?
- Ingestion of oocysts (infective immediately when passed in feces)
- Contamination of soil and water
- Filter feeding shellfish
C. parvum, C. hominis
How do veterinarians get exposed to crypto?
Safe to assume any mammal could carry zoonotic species
How do humans get giardia duodenalis?
Assembleges A and B
Cysts in water
Beaver fever
How do veterinarians get giardia?
Contact with feces
What are parasites that are primarily found in wildlife but also can successfully infect domestic animals?
- Echinococcus multilocularis
- Baylisacaris procyonis
- Trichinella
- Angiostrongylus
Most zoonotic infections of Echinococcus are from what species?
E. granulosus and E. multilocularis
Echinococcus species definitive and intermediate host
DH: Canids
IH: Small rodents
Human alveolar echinoccocosis - it can take…………. between infection point and development of clinical symptoms
10-15 years
Describe the clinical importance of Echinococcus multilocularis in the DH, IH, humans and dogs?
- DH - none
- IH - potentially fatal
- Humand and dogs - develop metacestode stage = alveolar echinococcosis (rare)
Why is echinoccoccus of recent concern in US?
- Signs may not develop years after infection
- Treatment is difficult and may require anthelmintic treatment for life
- Diagnosis of adult tapeworms in dogs is very difficult, eggs are indistinguishable from other taeniiid eggs
- Disinfection requres freezing -80C for several days, undiluted bleach for several hours, flame
- Detected in northern midwestern states, now in eastern (VA, MD, PA, VT)
Baylisascaris procyonis
- Racoom ascarid, small intestine
- Visceral and ocular larva migrans in humans, also subclinical can occur
- Attract transport hosts (rats)
- Eggs take a few weeks to become infected
- LATRINES!
- Humans exposed via ingestion of eggs, children w hx of pica
- Control = flaming, tx raccons w pyrantel, ivermectin, mocidentic, or albendazole or fenbendazole
Toxocara eggs bigger, worms have arrowhead
Baylisascaris procyonis in children
- Larvae continue to grow –> tissue damage and symptoms often severe
- Acute eosinophilic meningoencephalitits
- Death or lasting neuroological sequelae
IDEXX antigen test for adult worms (B. procyonis)
would help distinguish coprophaagy from infeciton
Trichenella transmission
- Carnivory or scaveging
- Ingestion of wildlife
- Freezing not an option
What domestic animals are most often infected with trichinella?
Pigs
Angiostrongylus cantonensis in animals
- Parasite of pulmonary arteries and right ventricle of rates and some other roden species
- IH = African giant snail
- Rats: first to CNS, then migrates to heart and arteries
Angiostrongylus cantonensis in humans
- Eosinophilic meningoencephalitis
- Ingested L3 –> CNS
- Severe, may be fatal
- Southeastern US, Caribbean Hawaii
- Recent cluster in Hawaii
Angiostrongylus cantonensis and vets
- No zoonotic infection from rates
- ddx for neurologic disease in endemic areas
- Not able to diagnose premortem
