Infectious Diseases Flashcards
what two microorganisms cause bovine viral diarrhea? (they aren’t both viruses ha ha!)
- pestivirus: a virus
2. leptospirosis: a bacteria
in what species is pestivirus found?
group of viruses in almost every species
what disease did pestiviruses cause a while ago and what is it called now?
was swine fever, now african swine fever
describe the symptoms caused by pestiviruses
diarrhea is a symptom, but the diease does NOT affect the digestive tract; repro tract is more affected
describe the range of symptoms caused by pestivirus?
can range from asymptomatic to hella bad
how do pestiviruses affect the repro tract?
causes abortion
when pestiviruses cause bovine viral diarrhea in persistently infected young calves, what does the disease develop into?
mucosal disease
how can pestivirus-caused bovine viral diarrhea be controlled and prevented? (3)
- improved biosecurity
- vaccination
- preventing entry, watching for asymptomatic individuals
describe what is sneaky about when pestiviruses cause bovine viral diarrhea infection at days 110-233 of pregnancy?
most cases are subclinical until BAM! abortion at days 110-233 of pregnancy if they get infected at this point in their pregnancy
describe what is sneaky about when pestiviruses cause bovine viral diarrhea infection at days 30-110 of pregnancy?
the fetal environment changes, causes persistent infection since the fetus is immunotolerant because pestivirus infects when the immune system forms, so the calf is born normal and then becomes cytophatogenic and develops mucosal disease
what are the two types of bovine viral diarrhea when caused by pestivirus?
- NCP: noncytopathogenic; no produce disease
2. cytopathogenic; produce disease
describe the symptoms of adults infected with pestivirus
mostly asymptomatic- not really much bovine viral diarrhea happening
what is leptospira spp.?
a spiral shaped bacteria that can cause damage to the liver, kidneys, and other organs of the animal
what is a serovar?
variations within species; the same species but it causes different reactions in each animal due to different proteins
how many serovars of leoptospira spp. are there?
over 200
what does the amount of serovars mean about leptospirosis? and its prevention?
huge range of species, each can cause different disease, so we want to vaccinate to develop a wide range of immunity
discuss the occurance of leptospira spp. (location, seasons, climate thing)
- occurs worldwide
- cases usually occur during summer and fall
- large outbreaks have occurred after floods
what animals are affected by leptospirosis? (6)
- cattle
- sheep
- goats
- pigs
- horses
- dogs
what animal is rarely affected by leptospirosis?
cats
describe transmission of leptospirosis
spread through the urine of infected animals, which gets into wataer or soil and can surivive there for weeks to months
how is leptospirosis spread?
through direct contact; bacteria can enter in cuts in skin or mucous membranes (eyes, nose, mouth), and HAIR, in contact with CONTAMINATED WATER
can leptospirosis be inhaled?
sure can
what animals are reservoirs/carriers of leptospirosis?
rodents
what is the one health importance of leptospirosis?
it is zoonotic
what sympoms does leptospirosis cause in cattle, sheep, goats, and swine?
fever and reproductive problems, like abortion
what symptoms does leptospirosis cause in horses? (4)
uveitis, affects the eye: eyelids reddened, photosensitive, and blink frequently or clouding of the eye
what is petichiae when it is caused by leptospirosis in horse eyes?
virus grows in blood vessels, causing them to rupture
what symptoms does leptosopirosis cause in dogs? (9)
- fever
- vomiting
- abdominal pain
- diarrhea
- weakness
- refusal to eat
- depression
- stiffness
- severe muscle pain
in what species are there vaccines available for leptospirosis? (3)
pigs, cattle, dogs
what do the vaccines for leptospirosis do?
help to prevent disease severity but may not completely prevent infection
why do we give so many kinds of vaccines for leptospirosis?
need multiple due to serovars
why should you wash your canned/stored foods to prevent leptospirosis?
rodents can urinate on them and spread infection
what kind of virus causes equine infectious anemia?
a retrovirus
describe the transmission of equine infectious anemia (2)
- transmitted by biting fleas or other vectors such as horse flies and deer flies
- Iatrogenic: can spread when re-using needles from horse to horse
what symptoms does equine infectious anemia cause?
- anemia
- thrombocytopenia
- epistaxis: bleeding from the nose
describe retroviruses: what they’re composed of and how they work
composed of RNA that gets transformed to DNA and enters the animal nucleus, tells the animal cell to make more virus, and lyses the cell when it leaves, resulting in cell death
is there treatment or a vaccine for equine infectious anemia?
nope
how do we keep an eye on equine infectious anemia in the United States?
surveillance through annual Coggins tests
describe how the Coggins test works
measures for antibodies for equine infectious anemia; if a horse was exposed, they will have antibodies
what happens if a horse receives a positive Coggins test?
a second test will be performed, and if the 2nd test is positive the horse will either be eutanized or isolated at least 200 yards away from any other equid
what kind of pathogen is equine herpesvirus (EHV)/ rhinopneumonitis?
an opportunistic pathogen
describe the infection timing of EHV1 and EHV4
an infection of the respiratory tract that first occurs in foals, but causes recurrent clinical infections in weanlings, yearlings, and young horses entering training
?what can EHV1 cause in naive (1st time mom) mares
outbreaks of abortion or birth of weak, nonviable foals
why does EHV/rhinopneumonitis first infect young foals and young animals?
the immune system is not developed yet, so this opportunistic pathogen sneaks in and hides inside cells until stress activates it
what are the most clinically important strains of EHV?
Type 1 (EHV1) and (EHV4)
what symptoms do Type 1 and Type 4 EHV cause?
respiratory and neurologic symptoms
describe the transmission of EHV/rhinopneumonitis
highly contagious, spreading through aerosolized secretions, contact with infected horses, and contaminated feed and water utensils
describe how the immune response protects horses against EHV/rhinopneumonitis
a strong immune system can prevent death, just like human herpes
is there anything that can’t be contaminated with herpes?
nope, it’s everywhere
is there a vaccine for EHV/rhinopneumonitis?
yes!
when and where was West Nile virus first discovered in the United States?
in New York in 1999
describe the transmission of West Nile virus
a vector-borne disease; mosquitoes are vectors and wild birds are resorvoirs that carry the disease far and wide
what symptoms does West Nile virus cause?
affects the nervous system: causes
- encephalitis (inflammation of the brain and spinal cord)
- muscle weakness
- partial paralysis
- convulsions
- coma
- death
how fatal is West Nile virus once horses show clinical signs?
is fatal nearly 40% of the time at that point