Flashcards in Infectious diseases Deck (185):
Clostridium botulinum types __ and __ affect birds; type ___ affects humans
C and E
What is the effective brucella vaccine for wild cervids
There is no effective vaccine
At what age should wild cervids begin testing for CWD
12 months of age
Which federal agency has jurisdiction over game meat and farmed cervids
Avian cholera is caused by ____; which is often introduced to poultry by ____.
_____ is the primary test for TB in cattle; _____ is the primary test for TB in captive cervids
Contagious Equine Metritis (CEM) causes _(clinical signs)__ in mares and __(clinical signs)___ in stallions
Short-term infertility and vulvar discharge
No clinical signs; acts as a commensal bacteria
Causal agent of CEM
Modes of transmission for CEM
1) direct or indirect venereal contact
2) transplacental or contact with birth tissues
How to test for CEM in carrier mares? In stallions?
1) Swab clitoral sinuses/fossa (can be intermittent shedders)- some positives are serologically negative
2) Ideal is to breed to two mares then test them; less ideal swab penis/urethra (culture/cytology)- males always seronegative
Causative agent Equine Piroplasmosis
Babesia (Theileria) equi
Equine piroplasmosis transmitted by ____
Ticks (Dermacentor variabilis and Boophilus microplus)
The reservoir species for Babesia (Theileria) equi is ____; the reserveroir species for Babesia caballi is ____
Horses and ticks (transovarial transmission)
Best ways to prevent equine piroplasmosis (3)
- Acaricides (needs tick vector)
- Need adequate number of infected horses in an area to support disease transmission
- Don't reuse needles/blood products
Clinical signs equine piroplasmosis
Anemia, fever, jaundice, dark urine, lethargy, exercise intolerance (mild to severe)
What is the risk for food poisoning from MRSA strains?
Low/none; they aren't enterotoxin producing staph aureus strains
What are the ten steps of an outbreak investigation
1. Determine the existence of the outbreak
2. Confirm the diagnosis
3. Define a case and count cases
4. Orient the data in terms of time, place, and person
5. Determine who is at risk of becoming ill
6. Develop a hypothesis that explains the exposure that caused disease and test this hypothesis
7. Compare the hypothesis with the established facts
8. Plan a more systematic study
9. Prepare a written report
10. Execute control and prevention measures
CWD transmissision routes?
Feces, urine, saliva
Offical tests for CWD herd surveillance?
(gold standard) Immunohistochemistry of obex or retropharyngeal LNs
Rapid ELISA of obex or retropharyngeal LNs
Within the CFR, standards can be written as "design standards" or "performance standards". What is the difference?
Design standards are very specific and require rulemaking to change, eg "ramps must be 36 inches wide and no more than 15 degree slope" (how-to is within CFR)
Performance standards are more vague in execution allowing flexibility over time, eg "ramps must be of sufficient size to allow free passage by livestock without touching any side" (how-to is in guidance documents)
Primary mode of transmission for :
1. Ingestion/tonsils/retropharyngeal LNs
Reservoir species for brucella in USA?
Elk/Bison in Greater Yellowstone area
Human modes of infection with brucella in US?
Hunting feral swine, illegally imported dairy products, less often contact with aborted tissues, foreign exposures
Birds have ___ type receptors for influenza viruses
Humans have ___ type receptors
Swine have ___ type receptors
Birds= 2, 3'-sialyllactose
Humans = 2, 6'-sialyl N-acetyllactosamine
Swine = both α-2, 3 and α-2, 6 sialic acid receptor sites (that's why they're mixing pots)
three conditions for a global influenza pandemic
1. A new subtype of influenza A virus is introduced into
the human population.
2. Virus causes serious disease in humans
3. The virus can spread easily from person-to-person
in a sustained manner.
Appropriate manners to decontaminate prion properties (such as CWD)?
Physical: Irradiation, dry heat, autoclave
Chemical: currently no EPA-approved but some may work
Infected carcass: only alkaline hydrolysis inactivates completely
Equine Herpesvirus Myeloencephalopathy (EHM) is caused by ____
Equine HerpesVirus-1 (but not all EHV-1 causes the neuro form)
Primary forms of EHV in horses are __ and ___
EHV-1 and EHV-4
Modes of transmission for EHV in horses?
Inhalation, contact with aborted tissues
Vaccines against EHV protect against __ form(s) of disease but not ___ form(s)
Protect against respiratory and abortion signs but not neuro signs
Vaccinate livestock against anthrax using _____; vaccinate people using ______
Modified live (Sterne's)
How to diagnose anthrax?
Culture lesions, blood,
How to tx anthrax?
Cipro, doxycycline, penicillin
Common name for brucellosis?
Common name for botulisum in birds?
Three forms of human plague
Bubonic, pneumonic, septicemic
Oral rabies bait exists for which wildlife species in US?
Vector species for tularemia?
Ticks (Dermacentor, Amblyomma)
Flies (Deer fly)
Three forms of human tularemia
Ulceroglandular, Typhoidal, Pneumonic (less likely ocular in children)
Prevention strategies for tularemia (4)
PPE for skinning wildlife
Cook game meat thoroughly
Avoid contaminated drinking/swimming water
Vectors for WNV?
Mosquitoes: Culex pipiens (night feeder), Aedes aegypti (day feeder)
Ticks: Argasid (soft), amblyommine (hard)
Flies: Hippoboscid flies (flat flies)
Trichinella larvae in meat can be killed by __ or __ but not ___ or ___
Cooking or freezing
Salting or curing
Testing for hantavirus in human cases is ____ or ____; or if deceased ____
IgM +/- IgG (most commonly) or PCR
IHC if deceased
Transmission of Schmallenberg virus is via____
Culicoides midges; maternal-fetal, infected aborted tissues, also isolated in bovine semen (experimental)
Clinical signs Schmallenberg in cattle is ____. Sheep/goats is ______.
cattle: fever, reduced milk yield, teratogenic abortions;
sheep/goats- minimal signs in adults, arthrogryposis
and hydranencephaly syndrome (AHS) in fetus/lamb/kid
Prevention strategy for Schmallenberg virus
Alter breeding schedule so that pregnancy doesn't coincide with culicoides activity
Chagas caused by ___ with ___ vector
Trypanosoma cruzi; Triatomine bug vector (Reduviidae)
Host species for Chagas
Opossums, skunks, raccoons, coyotes rodents
Disease in humans and dogs
Route of transmission for Chagas
- Wound contamination by bug feces
- Ingestion of infected vector (eg dogs eat bugs) or infected wild mammal
- Ingestion of contaminated food or drink (eg fruit juices with bug feces in it)
- Congenital (mother to offspring)
- Blood-borne (most NA blood banks screen for T.cruzi)
- Organ transplant
Diagnosis of Chagas in canines
IFA is gold standard (Ab detection); histopath of heart or ID of parasite on blood smear.
Some PCR available
Lone star tick = (species)
Deer tick = (common name, species)
Black legged tick aka Ixodes scapularis
Brown dog tick = (common name, species)
Wood tick; Dermacentor variabilis
Four zoonoses associated with black legged tick/deer tick/Ixodes scapularis
Lyme disease (Borrelia burgdorferi), Powassan disease virus, Anaplasmosis (Anaplasma phagocytophilum), Babesiosis (Babesia microti)
Most Lyme transmission comes from ___ tick stage
Nymph stage. No transovarial transmission, so larvae stage not infected; adults are more likely to be spotted and removed.
Three lone star tick (Amblyomma americanum) zoonoses:
Ehrlichiosis, STARI (Southern tick associated rash illness- ethiology unknown), Heartland virus
Main reservoir species for Ehrlichiosis all stages
White tail deer (less often dogs, coyotes, goats, raccoons)
Cytologic ID of Ehrlichia by ___
Morulae in neutrophils on blood smear
In human cases of WNV, __% have no symptoms; ___% have west nile fever, and __% have West Nile neuroinvasive disease (WNND)
< 1% meningitis, encephalitis
WNV fatality rate in horses?
30-40% (neuro signs, ataxia, circling, etc)
Symptoms of EEE and case fatality rate in horses?
over 90% fatal; early fever, anorexia progress to neuro signs
The incidence of WNV tends to affect the _____ ages while EEE tends to affect the ____ ages
EEE- very young and very old
After issuing a Veterinary Feed Directive, the vet must keep record of forms for ___ (time)___
Dengue virus immunity is ____
lifelong to specific subtype infected with only
Vector for dengue and Chikungunya virus
Aedes aegypti and albopictus
Common name for anthrax?
Wool sorter's disease
Robert Koch used ____ bacteria to prove Koch's postulates
Historically, Leptospira serovars ___ and ___ were most important in canine species, but now serovars ____ are emerging
Historical: L. canicola and L. icterohemorrhagiae
Emerging: L. pomona, L. grippotyphosa, L. autumnalis, L. bratislava
Lepto transmisssion routes
Contact with infected water, soil, urine, feces through abraded skin or mucous membranes,
direct ingestion, transplacental, bite wounds, venereal
Generally each lepto serovar has maintainence host species that (does/does not) cause illness in that species
Usually asymptomatic however can become ill
Reservoir species for L. icterohemorrhagiae
Reservoir species for L. canicola
Reservoir species for L. pomona
Cow, swine, skunk, possum
Reservoir species for L. grippotyphosa
Vole, raccoon, skunk, opossum
Reservoir species for L. bratislava
Rat, pig, horse
Reservoir species for L. autumnalis
Porcine Epidemic Diarrhea Virus (PEDV) routes of transmission
PED causes highest mortality in what age group of pigs?
Babies under 4 wk of age (up to 100% mortality); in older animals, vomiting and diarrhea lose some condition and drop in reproduction
Potential routes of transmission MERS?
Camel contact (respiratory, meat, milk), nosocomial, close aerosol contact
MERS shedding in camels is highest in what time/age
Young <2yr animals and during spring breeding season
Most susceptible species to vesicular stomatitis virus?
Horses, cattle, swine; less often sheep, coats, camelids,
Clinical signs VS
Oral vesicles (drooling, not eating); lameness/coronary band lesions, mastitis in dairy cows
Rule-outs for vesicular lesions in cattle
VS, FMD, bluetongue, Mucosal BVD, Epizootic Hemorrhagic disease, chemical injury, trauma
VS routes of transmission
Biting flies, direct contact with ruptured vesicles, contact with recently infected fomites
Clinical signs of VS in people; route of transmission
Malaise, high fever, results from direct contact with lesions or snorting/sneezing on person during PE
Swine brucellosis mechanisms of transmission?
Ingestion of infected birth/abortion tissues, semen, urine of swine, milk of B.suis infected cattle
Clinical signs of Brucella suis in swine? In horses?
Swine: Abortion, epididymitis/orchitis, weak piglets, swollen joints, infertility
Horses: Fistulous withers
Brucella suis cross reacts with what pathogen on serology
Definitive diagnosis Brucella suis?
Culture tissues @ necropsy: Repro organs, lymph nodes, spleen, liver
The Market Swine Test (MST) tests _____ for Brucella suis
culled breeding animals at slaughter
Reservoir for swine brucellosis in the US?
Swine Brucellosis is zoonotic. What categories of people are most at risk
Slaughter workers; feral swine hunters, swine producers, veterinarians
Routes of transmission for tularemia
Direct contact with infected animals, aerosols, inoculation into wounds, contaminated food/water, tick/fly-borne, lab exposure
Acute tularemia patients (animal/human) serology is negative until ____ time
2-4 weeks post-infection
Colorado Tick Fever is causative agent?
Colorado tick fever virus (reoviridae)
Vector for colorado tick fever?
Dermacentor andersonii (Rocky Mountain wood tick)
Brucella vaccination in cattle can prevent
Abortion but may not always prevent infection (large exposure may overwhelm vaccine immunity)
What strain of brucella is considered most virulent
Brucella RB51 vaccine (does/does not) produce antibodies that cross-react with wild-type infection on screening tests
Does not (no antibodies produced)
Vaccinating calves against brucella must be done when they are ___ age
between 4 and 12 months of age
Two common names for brucellosis in cattle? In people?
Bang's disease or contagious abortion in cattle
Undulant fever or Malta fever in people
Reindeer are most likely to get which species of brucella?
Which two brucella species cross-react on tests due to their rough colony formation
B. canis and B. ovis
Clinical signs of chronic chagas
Cardiac arrythmias, congestive failure, DCM
Two common names for coccidiomycosis
Cocci or valley fever
Geographic distribution for coccidiomycosis?
California and SW US
Geographic distribution for blastomycosis?
East of Mississippi
Routes of transmission coccidioidomycosis
Primarily inhalation, less often contact with birthing fluids, contact with disseminated disease, organ transplants
Clinical signs acute coccidiodomycosis?
Pulmonary granuloma, fever, rash (erythema), lethargy, malaise,
Populations at increased risk for coccidiodomycosis?
Within geographic area of California and SW USA, immunocompromised individuals (HIV patients, transplant recipients, pregnant women, people on steroids, lymphoma patients), with some genetic predilection for severe disease in African American and Asian persons
Reservoir species Cryptosporidium hominis? C. parvum?
Hominis: human only
Parvum: humans and mammals (including ruminants)
Mechanisms to disinfect water supply from Crypto?
Heat (pasteurization), filtration; less successful: UV or ozone
Geographic distribution of Coxiella?
Global, except not in New Zealand
most common mosquito vector for viral encephalites (WEE/VEE/EEE/SLE)
Which of the following cause disease in horses?
What is the amplifying host species for LaCrosse Encephalitis Virus
Chipmunks and small mammals (humans dead end host)
EEE amplifying host species?
Songbirds (humans, horses dead end hosts)
WEE amplfiying host species?
House sparrow/passerines, prairie dog, squirrel, jackrabbit, kangaroo rat (humans, horses dead end hosts)
SLE amplifying host species?
Migratory birds (humans dead end host)
VEE amplifying host species?
Horses, rodents (humans dead end host)
Which viral encephalitis agents makes best bioterror weapon?
VEE (can be aerosolized, human/equine cases occur simultaneously, lg number cases possible )
Tick-borne encephalitis virus is transmitted by what genus of ticks?
Mode of transmission Tick-borne encephalitis virus?
Bite from infected tick; raw milk consumption from infected cow/sheep/goat
Powassan virus vector?
Ticks (dermacentor and ixodes in US)
Powassan virus amplifying host species?
Small-medium rodents: woodchuck, squirrel, mice
Most common neuroinvasive arbovirus overall in US? Most common in children?
WNV overall, LaCrosse in children
What species are affected by Epizootic Hemorrhagic Disease? Which is most severely affected?
Rare: sheep/goats, Mod: cattle; cervids Most severe in white-tail deer
Most common clinical signs of EHD in cattle? In deer?
In cattle, milder with salivation/oral lesions, rarely coronary band erosions
In deer, three syndromes:
1) Peracute (resp distress, swell head/neck, death)
2) Acute/classic( extensive hemorrhage, salivation, bloody nasal discharge, erosions of mouth)
3) Chronic ( lameness, hoof lesions, rumen ulcers)
Vector species for EHD (Epizootic Hemorrhagic Disease)?
Culicoides spp (biting midges)
Ddx for Epizootic Hemorrhagic Disease (EHD) in deer?
Bluetongue, FMD, plant photosensitization
Ddx for Epizootic Hemorrhagic Disease (EHD) in cattle?
FMD, bluetongue, VS, BVD, Malignant catarrhal fever, bovine ephemeral fever
Route of transmission EIA (equine infectious anemia)
Blood transfusions/contaminated products, biting flies
Primary symptom Equine VIral Arteritis (EVA)
Abortion, rash, pneumonia (rarely or in foals)
Primary route of transmission Equine Viral Arteritis (EVA)?
Respiratory, venereal (vaccine preventable)
Most common serotype of FMD worldwide?
Which species has highest respiratory (aerosol) secretion of FMD?
Potential reservoir species for Heartland virus? Vector?
Reservoir: raccoon and white tail deer
Vector: Lone-star tick (amblyomma americanium)
Reservoir species Hendra virus?
Flying fox (fruit bat); horses can also become viremic enough to transmit to close human or horse contacts
Histoplasmosis associated with inhalation of contaminated soils high in nitrogen (enriched by feces of what species?)
Bats and birds.
Geographic predisposition for following fungal diseases:
Blasto: Eastern 1/3 of North America
Coccidoido: SW USA (desert areas)
Histo: Ohio and Mississippi river valleys
Reservoir in soil (not animal)
Most common state for lepto dx in the US?
Hawaii (50% cases)
Reservoir species LCMV (Lymphocytic Choriomeningitis Virus)?
House mouse; less likely hamsters, pet rodents
Clinical signs LCMV (Lynphocytic Choriomeningitis Virus) in people
Can cause birth defects, also aseptic meningitis, encephalitis
Route of transmission LCMV?
Contact with contaminated urine/feces/nestmaterials of rodents via broken skin, mucous membranes; also rodent bites, less likely solid organ transplant or maternal-fetal
What is the reservoir species for Malignant Catarrhal Fever?
Wildebeest and sheep-types can both infect cattle (herpesvirus)
Route of transmission MCF in cattle?
Vertical (maternal-fetal), or from inhalation/contact with infected sheep, wildebeests esp birthing products or nasal/ocular secretions
Routes of transmission plague?
Bite of infected flea; skinning/handling dead infected rodents, aerosol from infected animal/person (esp cats)
3 forms plague
1) bubonic/LN form
Intermediate host Diphyllobothrium
Intermediate host Echinococcus
Intermediate host Echinococcus
Intermediate host Taenia soleum
Which species can be latent carriers for Aujeszky's disease
Susceptible species pseudorabies
All mammals except humans, apes, rare in horses
Mechanism of transmission Aujeszky's disease
2) nose to nose contact,
3) contact with milk, urine, vaginal, preputial discharge,
Where is latent virus found in swine with Aujeszky's disease?
Trigeminal ganglia (herpesvirus)
Clinical signs Aujeszky disease swine?
Piglets- neuro, death
Older- respiratory, fever, abortions
Clinical signs Aujeszky disease cattle?
almost always fatal- focal intense pruritus, then progressive neuro signs
Diseases transmitted by Dermacentor variabalis (American dog tick)
Rhipicephalus sanguineus, common name ____ transmits what disease?
Brown dog tick; RMSF
Clinical signs RVF in ruminants
Abortion storms after heavy rainfall; youngstock deaths
Clinical signs RVF in humans
Self-limiting flu-like majority, 1-2% viral hemorrhagic fever
Mosquitoes, ticks, biting flies. also contact with infected dead animals (ie necropsy)
When submitting screwworm larve for ID, how should they be submitted?
Rabies vaccines used in state/local control programs should have at least __ year duration
Definition anthropozoonosis and example?
Diseases in animals that can be
transmitted to man (i.e., rabies).
Definition Zooanthroponoses and example?
Diseases in humans that can be
transmitted to animals (i.e., tuberculosis in cats,
Definition Amphixenoses and example?
Diseases affecting humans and
animals that can be occasionally transmitted
from one to another (i.e., staphyloccocal
Definition Euzoonoses and example?
Diseases in which humans are an obligatory host of the agent (i.e., Taenia solium or T. saginata)
Definition orthozoonoses and example?
Disease transmission cycle can be completed with
only one vertebrate reservoir (i.e. rabies).
Definition cyclozoonoses and example?
Diseases whose maintenance cycle requires more than one vertebrate species, but no invertebrate host (i.e., hydatid disease, taeniasis).
Definition metazoonoses/pherozoonoses and example?
Diseases whose maintenance cycle requires both vertebrates and invertebrates to complete their transmission cycle (i.e. arboviruses).
Definition saprozoonoses and example?
Diseases that depend upon inanimate reservoirs or development sites, as well as upon vertebrate hosts (eg Listeria)
Zoonoses for which symptoms are observed in animals and humans
Definition cryptozoonoses and examples?
Zoonoses for which there is only infection without symptoms in animals and/or humans.
- infection in animals/disease in humans: ornithosis
- Infection in humans/disease in animals: Ebola/Reston
Trichinella causes what two phases of infection in people?
Intestinal/enteral and muscular/parenteral
Source of most human trichinella cases in US?
Feral swine, other wildlife (bear, marine mammals), rarely commercial swine
Which subtype of tularemia is more lethal in humans?
Bovine TB slaughter surveillance looks specifically for what?
Granuloma lesions, especially in lungs, or LNs of head, chest, abdomen
Pearl's disease in bovids caused by
M. tuberculosis (granulomas on pleural walls
Crimean-Congo hemorrhagic fever route of transmission
Primary mosquito for transmission of Zika?
Mayaro virus produces a clinical syndrome most similar to what other arbovirus?