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
what is the shining light of West Nile virus?
vaccne is very effective, the US has been able to reduce incidence through vaccinations
in what region of the country might you need to vaccinate your horse year-round with a booster for West Nile virus and why?
in southern states because mosquitos year round
what is the oxygen preference of clostridial bacteria?
strict anaerobes
what happens to clostridial bacteria in unsavory conditions?
they form endospores, and can survive in harsher environments for a long time
what do clostridial bacteria produce generally? give an example
gas, swollen rumen (bloated)
what do clostridial bacteria produce in the vegetative form?
toxins
what is the vegetative form?
growing, not sporulated
where are clostridial bacteria found? general and then specific
ubiquitous in the environment: prevalent in soil and the intestinal tract of mammals
in what environment do clostridial bacteria germinate, and what is the result of that germination?
germinate in anaerobic environment, produce different toxins that cause different symptoms
do all species of clostridial bacteria cause the same symptoms?
nope, very different symptoms based on species
what kind of mortality rates are associated with clostridial bacterial diseases?
high mortality rates
what are the 2 common types of Clostridium perfringens?
Type C and Type D
what is Type C Clostridium perfringens disease also referred to?
necrotic enteritis, enterotoxemia
is Type C Clostridium perfringens diease specific to one area or species?
no it has global spread and affects multiple species
what are the symptoms of Type C Clostridium perfingens disease? (6)
- acute death
- diarrhea (yellow, brown, hemorrhagic)
- dehydration
- anemia
- weakness
- moribund
what does moribund mean?
close to death
what does Type D Clostridium perfringens cause?
enteritis in small ruminants
what is Type C Clostrodoium perfringens related with?
overeating or abrupt changes in diet
what does Clostridium difficile cause?
diarrhea in horses, piglets that are 1-7 days old, dogs, and chickens
what are the symptoms of Clostridium difficile? (6)
- acute death
- diarrhea (yellow, brown, hemorrhagic)
- dehydration
- anemia
- weakness
- moribund
what is Clostridium hemolyticum also called? (2)
- Red Water Disease
2. Bacillary Hemoglobinuria
where are the spores of Clostridium hemolyticum found? how are they passed on?
healthy animals; passed in feces and urine (which turns red = red water disease)
when does the disease caused by Clostridium hemolyticum occur?
only when the liver is damaged
where is Clostridium perfringens found?
lives in our intestines/microbiome all the time
how do the toxins produced by Type C Clostridial perfringens start doin their dirty work?
the toxins are produced in the intestines and then enter the circulation
under what conditions does acute death due to Type C Clostridial perfringens occur?
with exponential bacterial growth
how do you prevent Type C and Type D Clostridium perfringens?
with vaccinations
under what conditions does Clostridium difficile cause diarrhea in piglets aged 1-7 days and why?
when there is poor sanitation in the farrowing area because piglets have no microbiome to defend against infection
how do you prevent disease caused by Clostridium difficile?
with vaccination
what needs to happen concurrently in order for Clostridium hemolyticum to cuase disease?
fasciola hepatica (liver flukes) need to be present
describe the pathogenesis of how concurrent infections of clostridium hemolyticum and fasciola hepatica
- flukes penetrate intestinal walls
- flukes travel to liver
- bacteria attach to fasciola when they leave the intestine, so they also enter the liver and together they fuck you up
what is caused by the release of toxins from the bacteria Clostridium hemolyticum? (2)
liver necrosis and intravascular hemolysis (desctruction of red blood cells)
what are the symptoms of disease caused by Clostridium hemolyticum?
- sudden death
- fever
- anorexia
- pale, icteric mucous membranes
- port-wine urine
is port wine urine a pathognomonic symptom of disease caused by Clostridium hemolyticum?
not necessarily, juts a good indication
where is Clostridium hemolyticum found?
always present in microbiome
what is the risk factor that increases the chances of disease caused by Clostridium hemolyticum?
present of liver flukes (fasciola hepatica)
how do you prevent disease caused by Clostridium hemolyticum?
vaccinate against it in grazing animals in areas where flukes are present
what is the disease caused by Clostridium tetani also called?
lockjaw
where is Clostridium tetani found? (2)
- primarily a soil contaminant
2. may be shed by GI tract, since it lives in the intestinal microbiome
when does Clostridium tetani cause disease?
when introduced into the animal via a wound (accidentally, post-surgery, or ear tagging)
what happens to Clostridium tetani once it enters an animal via a wound?
the abcteria produce a toxin that targets the nervous system, casuing muscle spasms
what is typically observed in animal suffering from disease caused by Clostridium tetani? describe it
the Sawhorse stance: all muscles completely contracted, front legs stretched and out to give chest more room to breathe
what usually causes death from Clostridium tetani infection?
respiratory paralysis
what other clostridial bacteria produces similar symptoms to Clostridium tetani?
Clostridium botulinum
what is the issue with treatment of clostridial diseases?
it is challenging and costly
what is the costly treatment for clostridial diseases?
Antisera: the serum with antibodies that bind and inhibilitate the toxin being produced
what is the best method for dealing with clostridial diseases?
prevention!! is imperative!!! (vaccines)
discuss the vaccines available for clostridial diseases
there are many multi-valent vx availabile, with 8 or 9 way being the most common, but many of these vaccines do not contain C. tetani, so watch out for that
what is bovine respiratory disease complex also called? why?
shipping fever; occurs in cases of immunodepression or stress
is there just one cause of BRDC?
no, multiple causative agents of bovine respiratory disease complex
what is the leading cause of production losses in cattle? why?
bovine respiratory disease complex; cows focued on breathing, not producing
what does BRDC result in?
upper airway (nose, phayrnx, trachea) and lower airway (cranioventral lung lobes) disease
what are the symptoms of BRDC? (6)
- depression
- fever
- anorexia
- lowered head/ears
- soft cough
- abnormal lung sounds
what are the 4 viral agents of bovine respiratory disease complex?
- IBR: infectious bovine rhinotracheitis (a herpes virus)
- BRSV: bovine respiratory synctial virus
- PI-3: parainfluenza virus
- BVDV: bovine viral diarrhea virus
what are the 4 bacterial agents of bovine respiratory disease complex?
- Mannheimia hemolytica: opportunistic, always living in the animal
- Pasturella multicoda: also opportunistic
- Histophilus somnus
- Mycoplasma bovis
are bacteria and viruses the only agents that cause bovine respiratory disease complex?
no parasites and fungi also cause
what is the name of the cattle lungworm that also causes bovine respiratory disease complex
Dictyocaulus viviparus
what are 9 contributing factors to bovine respiratory disease complex?
- stress prior to shipping
- weaning and routine sx
- poor nutrition
- weather
- concurrent diseases
- crowding or co-mingling (viral transmission)
- transport
- time without food and water
- processing/handling
what are the 5 main preventative methods against bovine respiratory disease complex?
- VACCINATION!!
- cow/calf management
- proper conditioning of calves
- proper parasite control
- farm biosecurity
list 5 aspect of cow/calf management as relates to prevention of bovine respiratory disease complex
- ensure adequate colostrum intake- get that immunity!!
- optimal energy/protein intake of cow prior to calving
- control calving stress
- substitute colostrum
- vx cow to increase colostral antibodies prior to calving!!!
describe conditioning of calves prior to shipping as relates to prevention of bovine respiratory disease complex
make sure to do vx, needed surgeries, and weaning all 3 weeks prior to shipping to reduce stress
why is vaccination so important in treatment and prevention of bovine respiratory disease complex?
because once symptoms start, there’s not really much you can do
what is one of the most important healthc concerns for swine produciton today?
porcine respiratory disease complex
what is the leading cause of mortality in nursery and grower-finisher swine units?
porcine respiratory disease complex
what are the 6 symptoms of porcine respiratory disease complex?
- lethargy
- anorexia
- fever
- nasal and ocular discharge
- coughing
- labored breathing
do most pigs suffering from porcine respiratory didsease complex show symptoms?
NO. MOST are asymptomatic
what is the only sign of procine respiratory disease complex seen in asymptomatic pigs? why does this occur?
slower growth rate due to damaged lung tissue
what is the prevalence of pneumonia in pigs at slaughter due to porcine respiratory disease complex?
58%!!
does porcine respiratory disease complex always affect both lungs?
no! one can be completely unaffected
what is the nonfunctional portion of the lung due to porcine respiratory disease complex or other diseases called?
consolidated
where is there a higher rpevalence of porcine respiratory disease complex?
in crowded areas
can we still use meat from pigs with porcine respsiratory disease complex?
yeah, damage stays mostly in lungs
describe the multiagent characteristic of porcine respiratory disease complex
primary agents break barriers
secondary agents cause inflammation and other symptoms
when does the chance of contracting porcine respiratory disease complex from a viral agent increase?
in the winter
what are the 4 viral agents of porcine respiratory disease complex?
- PRRSV (porcine reproductive and respiratory syndrome virus)
- coronavirus
- swine influenza
- circovirus (PCV2)
what are the 6 bacterial agents of porcine respiratory disease complex?
- Mycoplasma hypopneumoniae
- Haemophilus parasuis
- Streptococcus suis
- Bordatella bronchioseptica
- Actinobacillus suis
- Actinobacillus pleuropneumoniae
which of the bacterial agents of porcine respiratory disease complex is a pain in the ass to get rid of and why?
Mycoplasma hypopneumoniae, mycoplasma bacteria have no cell wall, meaning they have zero response to most anitbiotics
which 3 of the bacterial agents of porcine respiratory disease complex are opprotunistic?
- Strepotococcus suis
- Bordatella bronchiosepta
- Haemophilus parasuis
what 3 things about the environment must be controlled to prevent porcine respiratory disease complex and why?
- ventilation
- prevent overcrowding
- temperature
a buildup of ammonia from too many animals (urine and manure gases) and poor ventilations is a risk factor
is treatment and prevention of porcine respiratory disease complex important on an individual basis?
no, more important in the herd
list the 3 general treatment and prevention strategies used in porcine respiratory disease complex
- management changes
- vaccination
- antibiotic usage
how can you specifically treat and prevent porcine respiratory disease complex? say general and then 3 specific
find out what agent you’re dealing with
- culture
- PCR
- serology
how do you plan a vaccination protocol for porcine respiratory disease complex?
use the specific methods to find out what agent dealing with and then plan program around that
