Infectious Diseases 3.0 Flashcards
what type of virus is caprine arthritis encephalitis (CAE) in terms of speed?
a lentivirus, slow
how is CAE typically transmitted?
- vertical transmission: mom to baby
2. horizontal transmission: goat to goat
how is vertical transmission of CAE accomplished?
from mother to kid through the ingestion of colostrium milk
what kind of disease does CAE cause in kids?
neurologic, erratice movement observed
what symptoms does CAE cause in adult goats?
- arthritis
- pneumonia
- mammary disease (endurant mastitis)
what characteristic position will you often find adult goats with CAE in and why?
kneeling due to joint pain
what is the prevalence of CAE in what countries and why?
greater than 65% in highly developed countries like US, Canada, France, Norway, due to highly selective practices in goats
where is CAE less prevalent and why?
local, low stress breeds of goats in less developed countries due to lower selection pressure and more outbreeding increasing heterosis and resistance
how does horizontal transmission of CAE take place? (4)
- direct contact
- fomites at feed bunks and water troughs
- ingestion of contaminated milk (from firs strip) in milking parlors
- iatrogenic: re-use of needles or equipment in contact with blood
does CAE have the ability to survive in the environmet outside a host cell?
sure does, can live in environment for a while
describe how caprine arthritis encephalitis is a lentivirus
can hide inside host cells as a latent provirus
what type of cells does CAE prefer to hide in and what does this explain?
it prefers joint cells because there is less access to the immune system that way, this explains the arthritis part
what kind of pathogen is CAE?
an opportunistic one because it thrives when the immune system is down
is there any vaccine or specific treatment for caprine arthritis encephalitis? how do you deal with it?
nope, can only provide supportive care for opportunistic bacterial infections
describe disease control of CAE (3)
- appropriate kid and colostrum management (PASTEURIZE)
- test and segregate to prevent spread
- cull adult infected goats
what must you also do when you encounter a case of CAE on your goat farm other than treat the animal?
report to state veterinarian
what kind of bacteria causes caseous lymphadenitis, what kind of bacteria is it, and why is it called that?
Cornyebacterium pseudotuberculosis, an anaerobic bacteria that produces similar symptoms to the bacteria that causes tuberculosis
describe Caseuous lymphadenitis
a chronic, contagious disease that affect lymphnodes and lymphatic tissue
what is the one health concern about caseous lymphadenitis and what precautions should you take?
is zoonotic! so wear gloves and PPE when dealing with cases
how resistant is Cornyebacterium pseudotuberculosis (causes caseous lymphadenitis) to the environment?
very resistant, can live on surface for up to 2 months and in soil for up to 8 months
how do the bacteria that causes caseous lymphadenitis enter the host?
through mucous membranes or damaged skin
what is the issue with the bacteria that cause caseous lymphadenitis once they are present in the soil?
they become endemic to that region and are almost impossible to remove
how long is the incubation period for caseous lymphadenitis?
1-3 months
does caseous lymphadenitis affect only internal lymph nodes?
no, affects internal and external lymph nodes, can actualy trace back infection point to most s affected lymph node
what is observed in lymph nodes affected by caseous lymphadenitis?
layers from where immune system blocks bacteria and the bacteria break through and cycle repeats
when are internal lymph nodes usually affected in caseous lymphadenitis?
when transmission occur through ingestion
what are the symptoms (2) of caseous lymphadenitis?
- chronic weight loss
2. failure to thrive
describe treatment of caseous lymphadenitis (3)
1, challenging to eradicate from an individual because recurrence is common
- treat individuals by draining or lancing abscesses tho
- treatment aimed more at limiting transmission to other animals in the flock
what are the 4 aspects of prevention of caseous lymphadenitis?
- STRICT BIOSECURITY
- awareness of fomites and disinfection of environment
- cull affected animals
- vaccination
why is chronic weight loss and failure to thrive the symptoms of caseous lymphadenitis?
swollen lymph nodes (mediastinal abscesses) push on esophagus and trachea = no food and hard to breathe = weight loss and failure to thrive
are chronic weight loss and failure to thrive the ONLY symptoms of caseous lymphadenitis?
no, abscess production everywhere can lead to other symptoms based on what grows near
are goats the only species affected by caseous lymphadenitis?
no, can occur in sheep too but is less common in sheep
what is contagious ecthyemia?
a disease in small ruminants that causes sore mouth; not many symptoms but hard way to live
what is Johne’s disease (paratuberculosis)?
a mycobacteria (bastard) that causes inflammation of the intestinal tract that leads to malabsorption of nutrients and makes growth hard; not mucn to do about this
what is the problem with vaccinating against Johne’s disease?
the mycobacteria could cause a cross reaction with tuberculosis tests
what type of virus is rabies?
a lyssa virus in that Rhabdovirus family
how many variants of rabies exist?
15
what is the important thing to keep in mind about rabies variants?
when species’ specific variants infect other species it can produce resorvoirs instead of infections
what mammals is rabies most common in?
canivores and bats
is rabies limited to infecting carnivores and bats?
nope, can affect ANY mammal
what is rabies?
acute viral encephalomyelitis
at what point is rabies fatal?
once clinical signs appear
describe the geography of rabies?
found throughout the world, global spread
what is the one health concern of rabies?
zoonotic
what are the 6 resorvoirs of rabies?
- dogs
- bats
- coyotes
- skunks
- foxes
- raccoons (3-6 wildilife)
describe the shift of rabies concern in recent years
we were more worried about domestic animals but vaccinations shifted focus to wildlife
why is rabies in wildlife a concern?
dogs and wildlife can both serve as resorvoirs, exhibit no symptoms but spread rabies, wildlife has easy access to livestock and dogs = bad news bears
if you are vaccinated against rabies and get exposed what happens?
infection is still possible but usually not fatal
describe transmission of rabies and what measures humans need to take
through virus-laden saliva into tissues, usually through bites or contact with wounds (so wear PPE!!)
what are the 3 phases of clinical signs of rabies?
- prodromal phase
- furious/acute excititative
- paralytic/endstage
describe the prodromal phase of clinical signs of rabies
vague, non-specific signs, lasts 1-3 days
describe the furious/acute excititative phase of clinical signs of rabies
“mad-dog syndrome” animal has no fear; will attack and use teeth, claws, horns, or hooves; alert posture
explain why fewer rabies infections occur from infected ruminants than infected carnivores
ruminants really only have horns to attack, so less ways to spread/cause wounds. carnivores bite and scratch
describe the paralytic form/endstage phase of clinical signs of rabies
ataxia and paralysis, coma, death within hours
describe the pathogenesis of rabies
- virus moves from site of entry to
- peripheral nerves to
- spinal cord to
- brain where replication leads to encephalitis and the salivary glands to continue transmission before
- to the rest of the body causing symptoms and host death
what is so scary about rabies and its transmission style?
it knows the salivary glands are the best place to go to infect other hosts, so it goes there before causing host death
how do you diagnose rabies?
euthanize if see symptoms, then send head off for histopathological analysis
what is the pathognomonic sign of rabies?
Negri bodies in the brain tissue
describe what happens governmentally (national and state) in terms of rabies control
there is a qualified lab to run histopathology for rabies in each state, and all cases must be reported to ensure that we keep the high public health risk of rabies as low as possible
at what point is rabies fatal?
once symptoms start
what organizations control prevention of rabies?
WHO and NASPHV (National Association of State Public Health Veteriarians)
list the 5 aspects of rabies prevention in dogs
- notification of suspected dogs, euthanization of clinical dogs and those bitten by clinical dogs
- reduction of contraction rates by leash, controlling dog movement, and quarantine
- MASS IMMUNIZATION
- stray dog control
- dog registration
describe rabies prevention in wildife, old times and now
until recently: population reduction of wildife
now: oral vaccines and recombinant virus in feed released into wild
what kind of virus is influenza virus
orthomyxovirus
what are the 4 types of influenza virus?
Type A
Type B
Type C
Type D
how is influenza virus Type A classified?
by hemagglutinin (H 1-18) and neuriminidase (N 1-11), the proteins outside the virus
which of the influenza viruses is constantly changing?
influenza A viruses