ANSC 251 EXAM 4 study guide

Porcine respiratory syndrome virus (PRRSV):
type of virus, impacts, first observed, common names, types of strain, symptoms/signs observed
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Porcine respiratory syndrome virus (PRRSV):
type of virus, impacts, first observed, common names, types of strain, symptoms/signs observed
Arteriviridae RNA virus

Impacts: Abortions, dead pigs, slow growth

First clinical syndrome: NC in 1987

Also called: Blue-ear pig disease, "mystery swine disease" and "mystery reproductive
syndrome"
term-6
Two types: Type 1 (European) and type 2 (North-American)

Clinical signs: Reproduction
late gestation:
-weak, stillborn, mummified piglets
-anorexia and agalactia in sows
Early gestation:
- abortions

Respiratory
-Dyspnea and tachypnea, poor growth, interstitial pneumonia

Cutaneous signs possible
-Hyperemia or cyanosis of extremities
PPRSV: Targets, immune response
Virus targets: macrophages
-Alveolar and tissue
-Acute disease: Lung, Lymphoid tissue, possibly kidney, spleen, heart, thymus, skills, reproductive tract, and nervous system
-Chronic phase: virus found in peripheral lymph nodes; tonsils

Effects on macrophages: decreased production of TNF-alpha and phagocytosis, induction of apoptosis

immune response: decreased IFN-alpha and TNF-alpha, increased IL-10 (suppresses TH1 response)
PPRS: who's at risk, sources of infection, prevention, tests to detect disease, if zoonosis, economic impact
Exists as quasispecies (frequently and quickly mutates)

Who's at risk: larger farms more susceptible to spread

Source of Infection: New introductions, infected semen, uncleaned transport

Transmission: Feces, semen, urine, mammary secretions, and nasal secretions

Live best: frozen conditions (years)

Prevention:
Minimize exposure (biosecurity, flow management, antimicrobials)
and maximize immunity (vaccination, acclimation, lactation management, proper nutrition)

Not zoonotic
Porcine endemic diarrhea virus (PEDV):
Coronavirus; 2 viral strains

First identified in U.S. in April May 2013 (rapid in Hog states)

Impacts: Severe diarrhea (dehydration + lack of nutrient uptake = piglet deaths)

Survives best: cool, moist environments

At risk: pigs of all ages (more severe in young pigs)

Transmission: fecal-oral route

Not zoonosis

Attacks: enterocytes
Bovine viral diarrhea (BVD or BVDV):
Description, types, impacts
Flaviviridae, RNA virus

2 biotypes: non-cytopathogenic and cytopathogenic

2 genotypes: BVDV-1 more frequent than BVDV-2
Europe: >90% type 1 & <10% type 2
NA: 50% type 1 & 50% type 2

Impacts: stillbirths, abortions/mummified fetus; immunosuppression
BVD:
Immune response, PI development, spread, survival, replication, testing, economic impact
Intestinal lymphoid depletion (necrosis of Peter's patch ileum)

PI development (Persistently Infected Carriers): Mother is infected 1-4 months of gestation --> cow and calf infected --> only dam becomes immune --> calf born persistently infected (93% of all PI's produced this way; 100% PI produce PI offspring)

Spreads:
-contact with PI through direct contact (nose to nose) or feces containing BVDV;
-semen, milk, saliva, urine, placenta, and birth fluid;
-through yards, stock trucks, and carried on footwear

Can survive: 7 days in environment

Replicates: epithelial cells and spread as free virus within infected blood cells

Testing: Ear Notch testing
Antibody tests only detect 3-weeks after infection

Economic impact:
industry total- $1.54-2.59B
Bovine respiratory disease (BRD):
complex, incidence, rates, impacts (psychological and economic), most at risk
Multifactorial (stress, viruses, and bacteria; all in normal bovine pop.)

Day of First incidence: 10 & peaks at 30 within 40 days of feed

Rates: up to 90% morbidity; up to 70% mortality

Impacts:
-Bronchopneumonia (common cause of dairy calf mortality; greatest economic losses in feedlot calves ($625 M/yr))
-Enzootic pneumonia (dairy calves)
-Shipping fever (beef calves)

Who's at risk: calves (31% deaths in U.S)
BRD: immune response
Causes of stress: transport, mixing, dehydration, lack of feed, environment, handling (physical, environmental, and psychological)

Stressors cause: decrease chemotaxis --> immunosuppression to not fight off common bacteria/viruses --> bacterial pneumonia

Transmission: pathogens enter via airways and mucosa surface

Not Zoonotic
Canine distemper (CDV):
description, transmission, symptoms, when infected...
Paramyxoviridae; RNA, enveloped

Triad of: Morbillivirus diseases (measles and rinderpest)

Transmission: mucosal route

Acute disease: fever, leucopenia w/ mucosal inflammation

Primary symptoms: coughing, shivering, conjunctivitis, nasal discharge, pneumonia, diarrhea, and vomiting

Secondary symptoms: pustular dermatitis and hyperkeratosis of nose and foot pads "hard pad disease", and neurological disorders (encephalitis --> death)

When infected: contagious, incurable, often fatal
CDV:
attacks, replication, clinical signs, viral stability
Attacks: respiratory, gastrointestinal, and central nervous system (multisystem viral disease)

Replicates: macrophages and lymphoid cells of upper respiratory tract

Clinical signs:
Main- Nasal discharge and diarrhea
Specific- Convulsions, incoordination, myoclonus (muscle spasm)

Viral survival: fragile and susceptible to ultraviolet light, heat, and common disinfectants; does not survive at RT (~25 C) more than few hours, can live 2wks at refrigerated temp (~5 C)
Parvovirus (PV): description, types, transmission, viral stability, Incubation, symptoms, risk-factorsParvoviridae; DNA, non-enveloped 2 types: Type 1 and 2 (a,b,c) Transmission: fecal-oral route Viral stability: extreme (>6 months); Inactivated by 4% sol. bleach, most disinfectants not effective (bc DNA); can survive at RT for 3 months Incubation period: 4-14 days Symptoms: depression, diarrhea and vomiting, fever, leukopenia, neutropenia, secondary bacterial infections, dehydration, shock, long term sequelae Risk factors: seasonal (3x July-Sept), breeds (Rotties, Dobs, and Sheps), sex (3x for intact), no vaccination (13x) Not zoonotic Vaccine availablePV: targets, conditions in puppies, clinical signsTargets: enterocyte crypt "valley" Cardiac form: myocarditis affects puppies infected in uterus or shortly after birth until 8wks Clinical signs: bloody diarrhea, poor/starving body condition (no possible nutrient uptake) Not zoonotic Vaccine availableFeline Immunodeficiency Virus (FIV): etiology, attacks, prevalence, immune causes, at riskRetroviridae-Lentivirus; RNA, enveloped Lentivirus: slowly develops; long incubation (<6 years) Retrovirus: same family as FeLV and HIV Attack's: lymphocytes (immune system) Prevalence: 2.5% in U.S. cats infected Causes: lymphopenia, loss of memory cell function, and decrease in antibody production from T-Cell stimulated lymphocytes leaves cat open for opportunistic infection At risk: vulnerable at any age; greater risk for outdoor free roaming cats (males 1.5-3x due to aggressive fighting)FIV: transmission, clinical signs, diagnostic testsPrimary transmission: deep bite wounds and scratches, cat's infected saliva enter other's bloodstream Clinical signs: (Pansystemic disease) -Poor coat condition and persistent fever with loss of appetitive, -lethargy -Gingivitis and stomatitis, chronic or recurrent infections of skin, urinary bladder, and upper respiratory tract -Persistent diarrhea -Slow but progressive weight lost -Ocular lesions -Behavior abnormalities -Anemia testing: -ELISA (i.e. SNAP-combo-detects anti-FIV antibodies) -Immunoblotting (uses antibodies to detect HIV related proteins) -PCR (detects virus itself; used for kittens born from FIV+ mom)FIV: treatments, prevention, vaccinationsTreatments: treated symptomatically; medications (antibiotics for 2nd infections, appetite stimulants, corticosteroids, immune modulators); nutritional support, fluid therapy, and dental care Prevention: Isolate affected cats, keep cats indoors, fixing outdoor cats, Vaccination: FIV vaccine provides 82% protection against strain A only; blood tests cannot tell b/w vax and FIV+ cat Not zoonoticTuberculosis (TB): World history, discovery, organism, stability, U.S. historyOld History: causes most deaths in humankind history; dates back at least 4,000BC; killed 1 in 5 deaths in 17th cen. London Discovered TB: Robert Koch; 1 in 7 deaths in Europe in late 19th cen. Bacterium: Mycobacterium bovis (M. bovis originated from cattle); gram (+); M. tuberculosis complex Stability: persists in cold, dark, moist conditions Zoonotic U.S. History in early 1900s: 80% of pop. infected before age 20; leading cause of death (10% caused by M. bovis); State-Federal Cooperative Bovine TB program established in 1917, 700 TB hospital by 1938 First sanatorium: Arkansas SanatoriumM. tuberculosis- 'human TB": transmission, prevalence, incidence, clinical signs, tests,Prevalence: 22 countries have 70% of cases today Transmission: Ingestion (unpasteurized dairy products; raw or undercooked meat), Aerosol, Breaks in the skin, Person-to-person (rare; immunosuppressed) Higher incidence: countries w/ controlled bovine disease; occupational risk groups (work with cattle) Clinical manifestations: asymptomatic, localized lymphadenopathy, skin disease, pulmonary disease Tests: Tuberculin skin testM. bovis- "in animals": types of hosts, clinical signs, causes, rates, tests, prevention, no vaccinationCattle= reservoir hosts (along with opossums, ferrets, badgers, bison, elk, African buffalo, While-tailed deer) Most animals= spillover hosts (sheep, goats, horses, pigs, dogs, others) Clinical signs: Early stage- asymptomatic Late stage- progressive emaciation; fever, weakness, inappetence; moist cough; enlarged lymph nodes Causes: Granulomas (tubercles) in lymph nodes and organs Rates: developed countries disease and death are rare Test: Tuberculin skin test (caudal fold, comparative cervical, single cervical); skinfold change >4.0 mm= positive Prevention and control: test-and-slaughter, test-and-segregate, slaughter surveillance, cleaning and disinfection No vaccine animals; treatment not advisedBrucellosis: bacterium, types, common names, history, economic impact,Bacterium: Brucella abortus; gram (-) coccobacillus Bacterium affecting cattle: B. melitensis and B. suis Common Names: Humans- Malta fever, undulant fever, Mediterranean fever, Rock Fever of Hierolater Animals- Bang's disease, Enzootic abortion, Epizootic abortion, Slinking of calves, Ram Epididymitis, Contagious Abortion History: David Bruce- established casual relationship b/w organism and disease; accredited Brucella nomenclature Bernhard Band- discovered Bacterium abortus could infect cattle, horses, sheep and goats Economic impact: In 1952 ~$400M, today <$1MBrucellosis in humans: at risk populations, incidence, transmission, incubation period, causes/complications, treatment, preventionAt risk: Occupational (cattle/dairy workers, vets, abattoir workers, meat inspectors, lab workers), Hunters, Travelers, Consumers U.S. incidence: 100 human cases/yr (consumption of unpasteurized foreign cheeses) Transmission: Ingestion (raw milk, unpasteurized dairy products), mucous membrane or abraded skin contact w/ infected tissues Incubation period: 5 days- 3 months Causes: multisystemic attack, cyclincal fever, flu-like illness Complications: Osteoarticular (20-60% of cases= arthritis, spondylitis, osteomyelitis), Hepatomegaly maybe, gastrointestinal, genitourinary involvement (2-20%= orchitis and epididymitis) Treatment and prognosis: rarely fatal (<2% if untreated), antibiotics necessary, death caused by endocarditis, meningitis Prevention and control: education, wear proper PPE, avoid consumption of raw dairy productsBrucellosis in animals: transmission (cattle and other animals), disease causes, causes for abortion, rates, tests, vaccination, prevention, U.S eradication,Transmission: In cattle Ingestion/contact (reproductive tissues/ fluids, milk, urine, semen, feces, hygroma fluids), in utero Transmission: Other animals contact with infected cattle Causes in cattle: Cows-abortion, stillbirth; weak calves; retained placenta; decreased lactation Bulls- epididymitis, orchitis Main carbon source for bacterium: Erythritol, produced from placenta for nutrients for fetus Causes: granulomatous inflammatory lesions, abnormal placenta, enlarged liver, swollen scroum Rates: spreads rapidly in naïve cattle, sporadic symptoms in endemic herds, death rare in adults Tests: direct examination, antigen tests, complement fixation, ELISA, milk testing, culture and identification, PCR Vaccination: RB51 for calves Prevention and control: Herd additions (vax calves, nonpreg Heifers, preg or fresh cows from disease free areas/herd, isolate and test beforehand); Bison in Yellowstone: up to 50% seropositive; bison management plan U.S. Eradication program 1934: test, slaughter, trace back, investigate, and vaccinate; Brucellosis ring test and market cattle identification Zoonotic and non-zoonotic speciesSummary of each lecture:PPRSV --> macrophages PPDV --> enterocytes BVD --> immunosuppression BRD --> multifactorial CDV --> multisystem PV --> enterocyte crypt "valley" FIV --> lymphocytes suppression TB --> enlarged lymph nodes Brucella --> abortion (placenta) Vaccines --> antibodies increase Antibiotics --> kill bacteria Bacteria can develop resistance against antibiotics (survivor)What disease are caused by bacteria?Tuberculosis and brucellosisWhat diseases are caused by virus?PRRS, PDV, BVD, BRD, CDV, PV, and FIVWhat is/are the differences between a bacteria and a virus?Bacteria are able to reproduce on their own through asexual reproduction; are larger in size (1-5 μM) Viruses need a host to replicate. Viruses are smaller in size (0.02-0.3 μM)Describe the epidemiological triangle1) Pathogen 2) Host 3) EnvironmentIs it safe to drink unpasteurized milk? What diseases can you possibly get from drinking it?No, there is a large risk of contracting a disease. You can get TB and BrucellosisWhat are the types of vaccines? How do each of one work differently in the immune system of the animalKilled Vaccines and Toxoids (nonreplicating) -Needs adjuvant -Slower onset of immunity -Booster usually required -May not stimulate as strong or long lasting immunity Modified Live (replicating) -More rapid protection -Less likely to cause allergic rxn -Risk of abortion/infertilitiesWhat do you known about antibodies?Proteins that attach to antigens, keeping them from harming the body Activated B cells can differentiate into antibody producing cells that attack their specific pathogenWhy is the need to give a booster to a vaccine?To produce a secondary immune response for a faster and larger immune response (higher antibody concentration) for longer memoryWhat is the difference between B-naïve cells and B-memory cells?B-naïve cells cannot produce antibodies, yet to turn into memory B cells B-memory cells produce antibodies to fight off pathogen after secondary encounterWhat are antibiotics? What types? Do they work on bacteria and viruses?Antibiotics treat (only) bacterium infections by attacking and preventing growth of/ or killing bacteria Penicillin is an antibiotic that can treat a wide range of infections and diseases: streptococcus, scarlet fever, syphilis, and gonorrhoeaWhat is the difference between a static and cidal antibiotic?Static= inhibition without killing; prevents growth Cidal= refers to killing off bacteriaExplain antibiotic resistance.The more the antibiotic is used the less effective it becomes. Antibiotics kill harmful illnesses causing bacteria to the body. With frequent exposure however bacteria can build up resistance to antibiotics. Common causes of antibiotic resistance are: -Over-prescribing of antibiotics -Patients not finishing their treatment -Over-use of antibiotic in livestock and fish farming -Poor infection control in hospitals and clinics -lack of hygiene and poor anitation -Lack of new antibiotics being developedWho was Alexander Fleming? Anything relevant he discovered?discovered the first antibiotic on accident; working as a bacteriologist at St. Mary's Hospital, he rediscovered the properties of penicillinWhat is beta-lactasmase?An enzyme bacteria produce to resist effects of penicillin for defense mechanismsWhat are the 5 antibiotic targets? (Inhibition of...)1) Bacterial cell wall (synthesis) 2) Bacterial plasma membrane (function) 3) Synthesis of bacterial proteins (translation) 4) Bacterial nucleic acids (DNA replication and transcription) 5) Bacterial metabolismWhat is "MIC" in the E-test?Minimum Inhibitory ConcentrationBiological warfare can be defined as "the use of toxins of biological origin or microorganism as weapons of war". However, the study of biological warfare and bioterrorism is complex. What are some of the reasons why this study is so difficult?☣ Lack of reliable scientific data regarding alleged bioterrorism attacks (especially before modern microbiology); ☣ Conditions surrounding any alleged biological attack - documents becoming susceptible to manipulations and becoming difficult to interpret; ☣ The historical distance of old histories about biological attacks, allowing for possible misunderstandingExamples of international protocols created to constrain the use of biological weapons--with dates. Did they work? Why1925 Geneva Protocol for the Prohibition of the Use in War of Asphysiating, Poisonous, or Other Gases, and of Bacteriological Methods of Warfare -prohibit use of biological weapons, but not their research and production 1972 Biological and Toxin Weapons Convention -First international treaty to ban an entire category of weapons of mass destruction; international treaties are basically unless an effective monitoring and verification procedure is in placeNations' false allegations of use of biological weapons were used to justify their political actions and goal or were even exploited as propaganda and pretext to war. Based on what you have learned from class and using your best critical thinking, discourse (no longer than two paragraphs) about, when it comes to information regarding bioterrorism and biological weapons, whether information should be made public or not.Suggested measures (from lec) -Information about potentially harmful pathogens should not be made public -Imperative publications of information about the development of biological weapons, to give scientists, politicians, and the interested public all the necessary information to determine a potential threat and devise countermeasures;