Lecture 19 (Viral Disease of Wildlife and Pocket Pets)

Epizootic Hemorrhagic Disease/Bluetongue Disease

*these cannot be clinically distinguished apart from each other

Epizootic Hemorrhagic Disease/Bluetongue Disease

*these cannot be clinically distinguished apart from each other

what is the most important viral disease of deer in the US?

a) Culicoides sonorensis

what is the confirmed vector for Bluetongue and EHD?

a) Culicoides sonorensis

b) Culicoides insignis

b) Culicoides insignis

what is the confirmed vector for Bluetongue in Southeast USA?

a) Culicoides sonorensis

b) Culicoides insignis

July through November

in what months is Bluetongue and EHD transmitted?

true

t/f: BTV and EHDV are widely distributed in temperate and tropical climates worldwide

Cervids (mammal of the deer family)

Hemorrhagic disease occurs only in ___________, mostly in white tailed deer, in the United States and Canada

3

there are _____ serotypes of EHDV and many serotypes of BTV

EHD and Bluetongue

clinical signs:

-this virus causes damage to small blood vessels, resulting in fluid loss, hemorrhage, and tissue damage

-signs range from sudden death to chronic disease

-pyrexia // depression

-reddening of periocular skin and nostrils

-swelling of head and neck

-neurological signs → ataxia // blindness // loss of fear

-sloughing of hoof/antlers

near water

where would a deer that has Hemorrhagic disease most likely be found?

b) EHDV or BlueTongue

A white tailed deer carcass was submitted for necropsy after being found dead near water with sloughed hooves. You find scaring in the forestomach, splenomegaly, pulmonary edema, swelling of tongue, and petechial hemorrhages. This deer likely died from...

a) Herpesvirus
b) EHDV or BlueTongue
c) Rabies
d) Chronic Wasting Disease

yes - only for farm animals

*you cannot vaccinate wildlife

is there a vaccine for Hemorrhagic disease?

b) Chronic Wasting Disease

which of the following wildlife diseases is caused by a prion and not a virus?

a) BlueTongue
b) Chronic Wasting Disease
c) Lymphocytic Choriomeningitis
d) HPAI
e) West Nile

Chronic Wasting Disease (Transmissible Spongiform Encephalopathy)

-this disease causes brain degeneration with vacuolation

-cause of disease is unsure but believed to be an infectious protein called a prion (misfolded protein)

-has a long (2.5 years and >) incubation period

-clinical presentation is one of progressive loss of condition

Colorado and Wyoming

what were the first two states to recognize Chronic Wasting Disease through deer farming and trophy hunting

true

t/f: several states have hunter surveillance programs for Chronic Wasting Disease

in lymph nodes when deer are clinically affected

*also lymphoid tissues in rectum

in contrast with BSE, how can prions be detected ante-mortem?

urine

prion material has been detected in __________ and horizontal transmission through infected placentae may also be possible

Tennessee

unfortunately, __________ has become the most recent state to detect Chronic Wasting Disease in free-ranging deer

Rabies virus

-this virus is transmitted from a bite or scratch of a rabid animal
-aerosol transmission in bat caves // contamination of mucous membranes
-incubation period is typically 1-3 months

Rabies virus

this virus replicates in peripheral nerves or non nervous tissue such as muscles then moves to the central nervous system via the spinal cord to the brain

Rabies virus

clinical signs:

-obvious clinical signs → excitable // hyperesthesia // agitation // aggression // head tilt // head pressing // drooling

-wildlife lose fear of humans and domestic animals

-paralysis leads to respiratory and cardiac failure

raboral V-RG:

-there is a fish paste-based recombinant oral vaccine that has been approved by the USDA

talk about controlling Rabies in wildlife

b) inserting Rabies G protein into Vaccinia Virus TK Gene

the fish-paste based recombinant oral vaccine used to address rabies in wildlife is made by:

a) inserting Rabies TK protein into Vaccinia Virus G Gene
b) inserting Rabies G protein into Vaccinia Virus TK Gene
c) inserting Vaccinia Virus TK protein into Rabies G Gene
d) inserting Vaccinia Virus G protein into Rabies TK Gene

bats

Rabies in humans is rare in the US but the most common source of human rabies in the US is from ______

Canine Distemper virus

-this virus is worldwide and occurs in raccoons throughout the Southeast
-Red foxes are also susceptible but appear to be more resistant than the highly susceptible gray fox

Canine Distemper virus

-this virus is transmitted by direct contact (aerosol droplets) → virus is shed from all excretions and secretions

-most lymphatic tissue becomes infected as well as the CNS

Canine Distemper Virus

clinical signs:

-respiratory distress // fever // anorexia

-serous nasal discharge and mucopurulent ocular discharge

-weight loss // diarrhea

-hyperkeratosis of nasal planum and footpads

Canine Distemper Virus

clinical signs:

-localize twitching

-paresis/paralysis beginning in the hind limbs (ataxia)

-convulsions // salivation // chewing movements of the jaws

-paddling movements of the legs

-urination // defecation

b) Canine Distemper Virus

this disease yields respiratory distress, fever, ocular discharge, hard pad disease, twitching, ascending paresis/paralysis, convulsions, salivation & chewing movements of the jaws, paddling movements of the legs, and acting confused while the wildlife animal (fox, etc) approaches humans

these signs should make us want to rule out rabies first, but then we could also consider...

a) Feline Infectious Peritonitis

b) Canine Distemper Virus

c) Monkey Pox

d) Eastern Equine Encephalitis

e) Chronic Wasting Disease

CDV shows nasal discharge, ocular discharge, diarrhea, hard pad disease etc.

what are some signs of Canine Distemper Virus (CDV) that aren't seen in Rabies?

(since the two overlap in a lot of things like loss of fear, salivation, ascending paralysis, clacking the gums together, etc...)

Cowpox in Cheetahs

this is a foreign animal disease (not in US)
-ulcerative skin lesions are observed

c) Monkey Pox

what viral disease had an outbreak in 2003 tied back to legal importation, pet shops, and the gambian giant rat and prairie dogs?

a) Feline Infectious Peritonitis

b) Canine Distemper Virus

c) Monkey Pox

d) Eastern Equine Encephalitis

e) Chronic Wasting Disease

Rabbit Hemorrhagic Disease

-this virus is a Caliciviridae and was identified in China in 1984
-hemorrhages in the lungs and liver
-killed 1/2 million rabbits in 6 months
-24-72 hour incubation time
-depression // fever // serosanguinous or bloody nasal discharge // nervous signs such as incoordination and shaking

Rabbit Hemorrhagic Disease

On a rabbit necropsy you see nasal hemorrhages, pulmonary congestion, edema, and zonal necrosis of the liver. What viral disease is this most likely?

there are currently no licensed vaccines available for rabbits in the US

-classified as a foreign animal disease

-there is a vaccine that has been made available through emergency use authorization since there was an outbreak in 2018

is there a vaccine for Rabbit Hemorrhagic Disease?

Myxomatosis in Rabbits

-this is a Poxviridae virus
-natural host is wild rabbits in NA
-seen as a severe generalized disease
-Blepharaconjunctivitis and swelling of the muzzle and anogenital region
-become febrile and listless
-often die within 48 hours of clinical signs

there is a vaccine available in Europe and in the US there is an attenuated California strain that has been used in vaccine but is not widely available

is there a vaccine available for Myxomatosis in rabbits?

in 1950 Myxoma was purposefully introduced to rabbits for population control in Australia → killed 500 million rabbits in 2 years → then rabbits developed genetic resistance to the disease

talk about Myxoma and Rabbit Hemorrhagic Disease being used to control rabbit overpopulation

Lymphocytic Choriomeningitis

-this virus is found in Hamsters

-a woman purchased a hamster from Petsmart → died of a stroke → organs were transplanted into another person who died one month later

-only 5% of house mice and hamsters carry this virus and they are infected asymptomatically

-wash hands with soap and water after handling
-use waterless alcohol-based hand rubs
-keep rodent cages clean & free of soiled bedding
-clean the cage in a well-ventilated area or outside
-wash hands after cleaning up pet droppings
-closely supervise young children
-do not kiss pet rodents or hold them close to your face

in fear of contracting Lymphocytic Choriomeningitis, what could you tell owners (who own pet rodents) to reduce the risk of contracting LCMV infection

a host from which infectious agents are not transmitted to other susceptible hosts due to insufficient viremia

what is a dead-end host?

a) Eastern Equine Encephalitis virus

clinical signs do not usually develop in most native species of wild birds infected; however, non indigenous birds submitted to SCWDS died due to this virus

a) Eastern Equine Encephalitis virus
b) West Nile Virus
c) Avian Influenza

a) Eastern Equine Encephalitis virus

clinical signs for non-indigenous birds, pen reared birds, & whooping cranes:

-depression // tremors // paralysis of the legs

-unnatural drowsiness // profuse diarrhea

-voice changes // ataxia // loss of muscle coordination

-involuntary circular movements

-death

a) Eastern Equine Encephalitis virus

b) West Nile Virus

c) Avian Influenza

-a killed-virus vaccine was used in captive whooping cranes to protect the rest of the breeding flock

-Emu farmers also use the EEE vaccine for horses

-mosquito free flight cages recommended for rehabilitation situations and bug zappers

talk about controlling Eastern Equine Encephalitis virus in wildlife

b) West Nile Virus

clinical signs:

-in susceptible animals → depression // ataxia // weight loss // torticollis // difficulty flying // death

-songbirds of the family Corvidae (crow family) are very susceptible

a) Eastern Equine Encephalitis virus

b) West Nile Virus

c) Avian Influenza

West Nile virus

-this virus was noted on an Alligator Farm in Florida

-neurological disease was noted

-upon necropsy → pancreatic necrosis // interstitial pneumonia // myocardial degeneration

-at first infection was thought to come from contaminated meat from sick horses or by bird feces

what virus was found?

NOT BY MOSQUITO TRANSMISSION

-fighting between alligators // fecal/oral between alligators // feeding infected meat (such as horse meat) // feeding opportunistically on infected wild birds

in the case where Alligators were found to have West Nile virus, how was this virus believed to be transmitted?

West Nile virus

it is important that when _________ virus is suspected, you submit the whole bird for diagnosis

-mosquito control

-there is not a West Nile virus vaccine approved for use in birds

-not much can be done for the wild bird population or alligators

talk about control for West Nile virus in wildlife

true

t/f: West Nile is zoonotic

c) H5N7

Which of the following is not one of the 3 HPAI associated with raptors, geese, and swans?

a) H5N1

b) H5N2

c) H5N7

d) H5N8

true

t/f: various species of raptors, geese, and swans have died of H5 virus infections