Exam 2 Flashcards
1
Q
Direct & Indirect Effects of Bioterrorism
A
o Economic
o Social & emotional impacts: Fear & panic
o Environmental consequences
o Malnutrition, sanitation, infectious disease
o Direct effects of biological weapons shrink in proportion to indirect effects
2
Q
Aspects of a “Good” Bio Weapon
A
o Stable o Short incubation o Low infectivity dose o High morbidity o Severe disease
3
Q
Bioterrorism Category A
A
o Highest priority agents
o Risk to National Security, rarely seen in US
o Easily disseminated
o Rapidly spread person to person
o High mortality, significant public health impact
o Cause public panic and social disruptions
o Require special action for public health preparedness
4
Q
Diseases in Category A
A
- Foot and mouth disease
- Classical swine fever
- Newcastle disease
- Vesicular stomatitis
- Highly pathogenic avian influenza
- Anthrax
- Botulism
- Plague
- Smallpox
- Tularemia
- Viral hemorrhagic fever
5
Q
Bioterrorism Category B
A
o Second highest priority agents o Moderately easy to disseminate o Moderate morbidity rates o Low mortality rates o Requires enhancements for diagnostic capacity and disease surveillance
6
Q
Diseases in Category B
A
- Brucellosis
- Epsilon toxins of Clostridium perf
- Glanders
- Psittacosis
- Q fever
- Ricin toxin
- Typhus
- Viral encephalitis
- Staph enterotoxin B
- Water & food threats
7
Q
Bioterrorism Category C
A
o Third highest priority
o Emerging pathogens that could be engineered for mass dissemination
o Ease of availability, production, and spread
o Potentially high morbidity and mortality
8
Q
Diseases in Category C
A
- Nipah virus,
- AI
- Hantaviruses
9
Q
When to Suspect Bioterrorism
A
o Clusters of disease or deaths
o Disease in unpredicted species, season, or geographic region
o Unusually high morbidity &/or mortality
o Unusual presentation or route of transmission (Aerosol)
o Endemic disease with increased incidence
o Single case of disease from uncommon agent
10
Q
Giardia Basics
A
- Many species
- Protozoan
- Humans: Giardia duodenalis (G. intestinalis, G. lamblia)
- Dogs: Giardia canis
- No environmental replication, cysts persist
- Dogs & cats carry A & B that can infect humans
11
Q
Giardia Transmission
A
o cysts shed in feces ->
o Cysts can survive for months in cold water ->
o Ingestion of cysts in contaminated water or food
–>
o Human-to-human transmission
– Primary source of human infections
o Animal-to-human transmission
– Only if assemblages A&B
12
Q
Giardia in Humans; basics & acute/chronic symptoms
A
o Most common intestinal parasite in humans o 1-3wk incubation o late summer o Asymptomatic carriers o Re-infection common
Acute Symptoms
• Cramps, nausea, V/D, gas, dehydration
Chronic Symptoms
• Weight loss & malnutrition
13
Q
Giardia Diagnosis in Dogs & Cats
A
o Do 3 fecal samples due to intermittent shedding
o Direct fecal smear
o Zinc sulfate fecal
floatation
o Fecal IFA & ELISA- SNAP test
o PCR- only method to determine Assemblage (Rarely done)
ELISA SNAP Giardia Test
o Warm to room temp
o Check results @ correct time
14
Q
Giardia Treatment in Humans Vs Animals
A
Humans:
• Metronidazole,
• Tinidazole
• nitazoxanide
Animals:
• Metronidazole,
• fenbendazole,
• albendazole
15
Q
Giardia Prevention
A
o Good hygiene o Avoid potentially contaminated water o Prevent contact w/ feces o Diagnose & treat infections o Giardia vx for dogs/cats resists oocyte shedding (discontinued)
16
Q
Leptospirosis Basics & Transmission
A
- Spirochete Leptospira
- Gram (-)
- Greater than 200 serovars
- Does not replicate outside of the host
- maintained in environmental water sources, mud, and wet soil for extended periods
- Global distribution
Transmission o Urine, blood, tissue, contaminated soil/water into abraided skin or mucosal surface o In utero o Horizontally through semen o Lab transmission o Floods
17
Q
Leptospirosis Clinical Signs
A
o Hepatic dz o Red water o Renal failure o Abortion o Mastitis o Uveitis in horses
18
Q
Leptospirosis Diagnosis & Treatment
A
Diagnosis o Clin Path for renal and hepatic disease o Kidney biopsy o Serology o FA & IHC of abortions or necropsy o PCR of urine & water o Culture (very slow weeks)
Treatment
o doxycycline,
o penicillin,
o oxytetracycline
19
Q
Leptospirosis Prevention
A
o Water sanitation
o Hygiene: protective clothing, hand- washing
Vaccination
• Swine, Cattle, Dogs
• Not cross protective
• Controversial to recommend
20
Q
Cattle Producer Leptospirosis Control Recommendations
A
o Vx for several serovars
o Vx calves 3-6mo to avoid maternal Ab
o Boost bi-annually
21
Q
Basics of Tularemia
A
o Francisella tularensis o Gram negative, aerobic coccobacillus o Hardy, non-spore-forming o Category A bioterrorism agent o North Americ & Eurasia o Survives well in H2O, moist soil, decaying carcasses
22
Q
2 Maintenance Cycles of Tularemia & Reservoir/Hosts
A
Maintenance Cycles
o Rabbits/hares/ticks
OR
o Voles, mice, squirrels, muskrat/direct contact or contaminated aquatic environment
o Reservoir
Lagomorph, wild rodents, ticks (transovarian)
o Hosts
• MANY species
23
Q
Transmission of Tularemia
A
o Biological vector: Dermacentor & Amblyomma ticks
o Mechanical vector: deer flies, mosquitoes
o Directcontact: bites, secretions
o Inhalation
during lawn mewing, shearing rabbits
o Ingestion of infected animals, contaminated food
o Lab BL3 to culture
o No person-to person transmission
24
Q
Why is Tularemia Used as a Bioterrorism Weapon
A
o Easy to acquire o Stable in the environment o Intentional contamination of food and/or water o Aerosolization o Multiple species infected
25
4 Presentations of Tularemia in Humans
Ulceroglandular infection
• An ulcerative skin lesion with lymphadenopathy
Pharyngeal infection:
• via ingestion
• cervical, submandibular, mediastinal lymphadenitis;
• exudative pharyngitis, oral ulcers
Septicemia (typhoidal)
• hepatomegaly, splenomegaly
Pneumonic
• via inhalation
• Radiographic and clinical evidence of pneumonia, pleuritis,
• 60% fatal if not treated
26
basics & 3 forms of Tularemia in Animals
o Fever, lethargy, anorexia, stiff gait, increased pulse and respiration, coughing, vomiting, diarrhea and pollakiuria
incubation:
• 3-5 days, (1-14 days)
Ulceroglandular form:
• cutaneous ulcers & regional lymphadenopathy
Septicemic form:
• hepatomegaly, icterus, sheep
Pneumonic form:
• rare
27
Tularemia Diagnosis, Treatment, Control
```
Diagnosis
o Serology: 4-fold change
o Culture of blood, aspirate, exudate or
biopsy
o Direct FA
o PCR
```
Treatment
o Doxycycline, tetracyclines, chloramphenica, ciprofloxacin
o Resistant to Beta-lactams: Penicillin & cephalosporins
```
Control
o Prevent pets from hunting rodents/rabbits
o Tick control
o PPE around infected animals
o Food hygiene
o No Vx
```
28
What is an Emerging Dz
```
o Appearance in new host
o Changes in pathogen’s underlying epidemiology
o Evolved strains
o Recent & 1st entry into a host
o Increased incidence
```
29
Factors of Pathogens Contributing to Emergence of Dz
Antimicrobial resistance
• Transformation
• Transduction
• Conjugation
```
Genetic adaptation & change
• Nucleotide substitution
• Natural selection
• Recombination
• Reassortment
```
30
Factors of Humans Contributing to Emergence of Dz
```
Human demographic changes
• Increased human contact
• Increased contact with wildlife
• Intensification of agriculture
• Population displacement
```
Human behavior
• Sexual practices, IV drug use: HIV
• Intent to harm: Anthrax, Botulism
• Domestication of animals: Toxoplasma
Human susceptibility to infection
• Immunocompromising conditions: HIV, cancer
• Nosocomial infections: SARS, Ebola, MRSA, MERS-CoV
• Transplants/infusions: HIV, Cryptococcus neoformans, Baboon cytomegalovirus
• Implants/surgical instruments: vCJD, fungal meningitis in contaminated steroid injections
31
What does R sub 0 mean in Emerging Dz
o <1 = limited spread
o 1 = endemic
o >1 = epidemic
32
Basics of Plague & Transmission
o Yersinia pestis
o Gram (-) coccobacilli
o Slow growing
o 5-15 human cases annually
Transmission
• Flea bite
• Flea ingestion
• Humans can get it through aerosols from infected cat
• Humans can get from eating infected goat
33
3 Cycles of Plague
Sylvatic (wild)
• Reservoir = rodents (prairie dog, rabbits, mice, dogs)
• Vector = wild rodent flea
Urban (domestic)
• Reservoir = urban black rat
• Vector = original rat flea – xenopsylla cheopis
Human
• Bubonic plague from contact w/ sylvatic or urban reservoir or arthropod vector bite ->
• Transmit to other humans ->
• Pneumonic plague
34
Plague; 3 Forms of Human Dz
Bubonic plague
• Buboes
• Lymph node swelling in inguinal region
Black Death
• Septicemia & DIC Gangrene of extremities
Pneumonic plague
35
Plague; Dz in cats vs dogs vs others
Cats:
• Highly susceptible to infection
• Bubonic: fever, lethargy, anorexia, lymphadenopathy
• Septicemia: fever, lethargy, anorexia, vomiting, diarrhea, weak pulse, DIC, respiratory distress Pneumonic form
Dogs:
• Increased resistance to Plague
• fever, lethargy, submandibular lymphadenopathy, oral lesions, cough
Goats & camels, llama
• susceptible
Cattle, horses, sheep, and pigs
• don’t develop clinical disease
36
Plague; diagnosis in cats
Presumptive:
• In-house gram stain of lesion
• homogenous gram (-) bacteria
State public health lab or CDC lab
• LN aspirate, swabs of lesions or oral cavity
• IFA for Y. pestis antigen
• Cultures-slow growing
Serology:
• 4 fold rise in titer
37
Plague; treatment in cats
* Initiate prior to definitive diagnosis
* Streptomycin, Gentamicin, Doxycycline
* Tetracycline, chloramphenicol, sulfonamides
* Keep cats hospitalized and isolated
* Use IV antibiotics for 1st 72 hrs
38
Plague Prevention
* Rodent control and Flea control
* Keep pets indoors & prevent hunting
* Use appropriate PPE in animal examinations
* Wear gloves/mask when hunting & handling wildlife that may be suspect
* Inform public health officials, veterinary regulatory officials
39
Plague as a Bioweapon
* Aerosol transmission
* High mortality and morbidity
* Previously used as a biological weapon
* Category A agent
40
Sources of Microbial Food-Borne Illness
Foods of Animal Origin
• Meat and meat by-products
• Milk, milk products
• Eggs
Foods of Plant Origin (fruit, veg & grain)
• Contamination with feces, urine or carcasses from infected animals &/or humans
• 2006 E. coli in spinach linked feral swine
Humans
• norovirus,
• Hepatitis A
41
Role of Vets in Food Safety
o Information source
o Treatment and preventative care of agricultural animals
o Biosecurity for agricultural animal producers
o Home slaughter & when to send animals to slaughter
o Employment in food safety
o Food safety for pets
42
Trichinella spiralis; Main Source, Prevention
o From domestic swine or wild game
Prevention
• Rodent control
• Don’t feed raw meat to pigs
• Garbage must be cooked
43
Trichinella spiralis; Measures at Processor to Prevent Human Infection
Inspection
• Microscopic
• No U.S. Inspection unless exported
Cooking
• Ready-to-Eat Products
44
Cooking Rules for Meat
* DESIGNED TO GET RID OF TRICHINELLA
* Get rid of salmonella in poultry
For Whole Cuts of Meat
• Cook to at least 145° F (63° C)
• allow the meat to rest for three minutes before carving or consuming.
For Ground Meat
• Cook to at least 160° F (71° C);
• ground meats do not require a rest time.
For All Wild Game (whole cuts and ground)
• Cook to at least 160° F (71° C).
For All Poultry (whole cuts and ground)
• Cook to at least 165° F (74° C)
• for whole poultry allow the meat to rest for 3 minutes before carving or consuming.
45
Freezing Rules for Meat
* Freeze pork less than 6 inches thick for 20 days at 5°F to kill any worms.
* Freezing wild game meats may not effectively kill all worms
46
Disposing of Dead Animals
```
o Incineration
o Rendering
o Burial
o Landfill
o Compost
o Natural decomposition (frowned upon)
```
47
HACCP
o Hazard Analysis and Critical Control Points
o Scientific methods to identify and prevent hazards
o Efficient and effective government oversight
o Places responsibility on the food producer and manufacturer
48
7 Principles of HACCP
* conduct hazard analysis ->
* identify critical control point ->
* establish critical limits for CCP ->
* Establish monitoring requirements ->
* Establish corrective action ->
* Establish record keeping ->
* Establish verification procedures
49
Critical Control Points for Meat
Inspection
• Antemortem
• Postmortem
Process
• Sanitation
• Temperatures
Microbiologicaltesting
• Salmonella, E. coli, Listeria
Drug residue testing
50
Antemortem Inspection; Who is inspected? What are the designations?
o All cattle, sheep, goats, swine & horses on the day of slaughter: in motion & at rest
o portion of birds from each truckload are observed
Designation
• Released for slaughter (99.5%)
• Suspect: slaughtered at end of day
• Condemned: fever, systemic disease, all down animals due to concernfor Bovine Spongiform encephalopathy
• Euthanized- carcass not used for human food
• heat or transport stress: rest, medical treatment, re-inspected on day of slaughter
51
Body Temp that Renders an Animal Condemned
* 106° F: swine
* 105° F: cattle, sheep, goats, horses
* <96° F: moribund
52
Bovine Spongiform Encephalopathy Specified Risk Materials
Condemned from all cattle
• Distal ileum
• Tonsils
```
Condemned from cattle 30 mo and older
• Skull
• Brain
• Trigeminal ganglia
• Eyes
• Vertebral column
• Spinal cord
• Dorsal root ganglia
• In order to keep many meat products, cows must be slaughtered before 30 mo
```
53
Bovine Spongiform Encephalopathy Basics & Testing
o All recumbent cattle are condemned on antemortem inspection
o High risk cattle tested for BSE
o All rabies suspect cattle which test rabies negative
Testing
• Test obex
• rapid immunoassay on brain tissue confirmed by IHC & western blot
54
Post Mortem Inspection Basics & Order of Inspection
o Prions, Infectious agents, Toxins
o Subjectivity: Your definition of acceptable from “poke and sniff” may be different than mine
o Only evaluates risk at one point in time
o Healthy animals may have pathogens in their system like Salmonella
& E.coli
o Focus on high risk areas
Order of Inspection
• Head
• Viscera
• Carcass
55
Options for Animals Falling Antemortem & Post Mortem Inspection
```
Antemortem inspection
• Pass for slaughter
• Pass for slaughter as “Suspect”
• Condemned
• ~0.5% of animals examined ante-mortem are classified as suspect or condemned.
```
```
Postmortem inspection
• Pass entire carcass
• Condemn portions of
carcass
• Condemn entire carcass
• Pass for “restricted” use - cooked products
```
56
Primary Source of Microbes in Meat
Feces
o from removing GI
o from hide
o contaminating ground meat
57
Residue Testing of Meat
FAST:
• Fast Antimicrobial Screen Test
KIS:
• Kidney Inhibition Swab
• Use to find drugs/antibiotics
Chemical testing
58
Specific Microbes to Test Meat for
o Generic E. coli testing for process control (Measures fecal contamination)
o Salmonella & Campylobacter testing
o E.coli O157:H7 and other shiga-toxin producing E.
coli (S-TEC) testing in raw ground beef
o Listeria monocytogenes testing in ready-to-eat
products
o BSE surveillance on high-risk cattle
59
Classifying Drugs as RX or OTC
o Determined by the FDA
o How difficult is it to use the drug?
o Rx drugs can only be dispensed by or on order of licensed veterinarian
o Some drugs may be Rx for some dosages /routes and OTC for others
o Can only prescribe drugs if there is a vet/client/patient relationship
60
Definition of a Vet/Client/Patient Relationship
o The vet has assumed responsibility
o Client has agreed to follow the vet instructions
Vet has enough knowledge of the animal(s) to initiate a diagnosis & treatment
• by direct examination of the animal(s)
• by medically appropriate and timely visits to premises
o Vet is readily available in the event of adverse reactions or failure of the treatment regimen.
61
Rules for Putting Drugs in Food
o FDA approval required
o Need RX for antibiotic deemed medically important in food & water
o Not used for growth promotion
o Only approved at specific levels in feed
o No ELDU (extra-label drug use)
62
Animal Medicinal Drug Use Clarification Act of 1994
o allows veterinarians to prescribe extra-label uses of certain approved animal drugs and approved human drugs for animals under certain conditions
63
When is ELDU Allowed in Food Animals
o By or under supervision of veterinarian
o Only FDA-approved drugs
o Valid Vet/Client/Patient relationship
o For therapeutic uses only...not for growth
promotion/production
o Not in feed
o No tissue residues
64
Drugs Banned in Food Animals
```
o Chloramphenicol
o Clenbuterol
o Diethylstilbestrol(DES)
o Dipyrone(non-steroidalanti-inflammatory)
o Glycopeptides
o Gentian violet
o Nitroimidazoles
o Nitrofurazone
o Aadamantine & neuraminidase inhibitors: Anti-virals used to treat influenza A
```
65
Pathogens in Mammary Gland
o Contaminate milk before leaving cow
o Coxiella burnetti
o Mycobacterium bovis
o Brucella abortus (B. melitensis)
66
Pathogens that contaminate milk outside of mammary gland
```
o From fecal contamination
o STEC
o Salmonella
o Listeria monocytogenes
o Campylobacter jejuni
o Yersinia
```
67
Basics of Bacteria that cause Dz due to preformed toxins
o intoxication due to preformed toxins, not infection
o Bacteria do not have to be replicating or even be alive to cause disease
o Very short incubation time (few hours)
o Usually only upper GI symptoms (nausea and vomiting)
o Staph aureus
o Clostridium botulinum
68
Staph aureus Basics, Danger Zone, Reservoirs
* Preformed toxin
* Toxin resistant toheat
* Bacteria may be killed but toxin will still be present
* Contamination happens during food prep
Danger Zone
• Between >40F <140F
Reservoir
• Human & animals
69
Clostridium Botulinum Basics, Reservoir, Sources
• Potent neuroparalytic exotoxin
Reservoir:
• Clostridial spores in soil
• Organism in GI tract of some animals
• Spores on fresh food are harmless
Source
• Improperly canned food
• Low acid canned foods
• Reason infants shouldn’t eat honey
70
Basics & Species of Bacteria causing Dz due to production of toxins w/in intestines
```
o Organisms alive & replicating
o Toxin causes dz
o Incubation time btwn hours & days
o Intoxication due to toxins made in body
o Clostridium perfringens type A
o E. coli O157:H7
o Vibriosis
```
71
Clostridium perfringens type A Reservoirs, Incubation, Clinical Signs, Prevention
Reservoir
• Soil
• GI tract of healthy people & animals
Incubation
• 6-14hrs
Clinical Signs
• Usually nausea
• Usually no vomiting or fever
Prevention
• Keep hot food above 140F
• Reheat food to greater than 165F
72
E. coli O157:H7 Effects in mans & reservoirs
* Causes hemolytic uremic syndrome
* 5% of affected children die
* many types of shiga toxic E. coli which cause similar dz
Reservoirs
• Dairy cattle 4-7%
• Feedlot cattle 9-12%
• Prevalence peaks in summer months- up to 50%
• Fecal shedding normally days to months
• “Super-shedders”- shed large amounts up to a year
• Also sheep, goats, deer, pigs, horses, dogs and turkeys
73
Vibriosis Basics
* Vibrio parahemolyticus or vulnificus
* 4-96hr incubation
* consumption of raw or poorly cooked fish & shellfish
* manufactured toxin
* human & environmental reservoirs
74
Bacteria causing Dz due to Invasion of Intestinal Epithelial Cells; Basics & Species
```
o Long incubation time
o Systemic signs
o Blood Ds
o Salmonella
o Campylobacter
o Listeria monocytogenes
```
75
Basics of Salmonella in Humans
* Very large cause of Dz
* Vomiting, diarrhea (+/- blood), fever
* Bacteremia, endocarditis, pneumonia,
meningitis, septic arthritis
* S. Typhimurium
* S. Enteritidis
76
Sources of Salmonells Infection in Humans
* Dry foods and mixes
* Common in peanut butter
* Small turtles
(rules for size of turtle sold in shop)
* Poultry (chicks)
* Petting zoos
* Calf raising operations
* Diarrhetic Horses
77
Salmonella; Current Concerns & Reservoirs
Current Concerns
• Increased multidrug resistance
• Rise in treatment failures and increased hospitalizations
• Incidence has not decreased despite safety measures
Reservoirs
• horse, pig, cattle, dogs, cats, rodents, poultry and other birds, reptiles, amphibians, fish
• up to 86% in laying hens
• up to 90% in reptiles
78
Basics of Campylobacter
* Usually beef, dairy, poultry
* Can also be shed by pets
* Outbreaks associated w/ raw milk
* Causes Guillan-Barre syndrome
79
Basics of Listeria monocytogenes
* Usually post-processing contamination of deli meat, smoked fish, raw milk products
* Multiplies at refrigeration temps
* Causes miscarriage
* Affects elderly & immunocompromised
80
Yersinia enterocolitica & pseudotuberculosis
* Usually from swine
| * Comes from eating pork & chitlins (intestine)
81
Limits to Feed Order (VFD Prescription)
* Goal was to reduce use of human antibiotics in cows
* Require same things as Rx label
(Meat, Milk, Egg withdrawal intervals )
* Expiration Date
* Specific diagnosis
* Specific animal, pen, or group of
animals
* At the end of the period, group of cattle, or pen rotation – need new diagnosis and feed order
82
Antibiogram
* Annual cumulative summary of hospital-specific antimicrobial susceptibility rates
* Help in selection of empirical antimicrobials while waiting for results of C&S
* You can ask your diagnostic lab if they provide the service (some do)
83
Minimize Antimicrobial Use by...
* Determining if necessary thru standard diagnostic plans
* Start with a narrow- spectrum drug
* Obtain culture and susceptibility (C & S) data
* Target therapy based on C &S data
* Use antimicrobial use guidelines in your practice
* Recognize your own bias and external factors influencing Rx
