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Protection of the environment... > PP 1 > Flashcards

PP 1 Flashcards

1
Q

Name the stages of disinfection and definition:

A

Disinfection is the elimination (removal, inactivating and killing) of all microorganisms that may cause disease or adverse effects on human health.

Stages:
1. Preparatory work: area, product, preparation of disinfectant and equipment, protective clothes and footwear
2. Mechanical cleaning (most important): remove biofilm
3. Disinfectant: spray or aerosol
4. Deactivation: neutralisation, removal of residues
5. Control of efficiency: bacteriological swabs
6. Finishing work: protocol

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2
Q

What does sanitation include?

A

Disinfection
Insect control
Rodent control
Careful and safe removals of cadavers and waste
Hygiene of the environment

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3
Q

Describe bait and bait boxes:

A

Bait is a substance used to lure rodents and kill them. It appears similar to what the rodents usually eat, and placed in locations where rodents or their droppings are seen.

Bait boxes are boxes with two holes around 5-7 cm in diameter. They contain a station inside that must be covered, to protect the bait from weather, people, pets and other animals. Boxes should be placed near walls.

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4
Q

Physical disinfection includes:

A

Heat, cold, desiccation, radiation, UV, ozone

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5
Q

What is the aim of preventive disinfection in different animal housing?

A

Decrease microbial load in the environment
Eradicate pathogens
Decrease levels of all microorganisms

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6
Q

What are the systems of housing?

A
  1. All in all out: performed after each removal of animals from the house, before next batch enters
  2. Continuous: minimum 2 times per year
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7
Q

Peracetic acid is stable or unstable?

A

Unstable

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8
Q

Peracetic acid preparations:

A

Persteril: 32-36%, minimum 15%
Pedox: bacteria, viruses, fungi, mycobacteria, algae

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9
Q

Peracetic acid preparations properties:

A

Wide range of temperatures, 10-20*C
Low concentrations: 0.1%, 0.3%, 0.5%, 0.9%
Low ET: 10 mins
Leaves no toxic residues

Peracetic and lactic: aerosol, used in presence of animals in volumes of 5 ml / m^3

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10
Q

Hydroxides - properties, MOA, preparations, percentages:

A

Alkali disinfectants
Corrosive
Active against G+ and G- bacteria and viruses
Change pH, destruction of cell culture, hydrolysation of proteins
Generally stable and prepared per total volume

Sodium hydroxide
Potassium hydroxide
Calcium hydroxide
Ammonium hydroxide

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11
Q

Sodium hydroxide (NaOH):

A

Lye, caustic soda, spray form
Highly corrosive
Activation at 70-80 degrees
Unstable in storage (need airtight container)
Gram negative 1%
Gram positive 3-5%
Viruses 2-4% (ET: 1-2 hours)
Spores 5-10%

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12
Q

Potassium hydroxide is present in:

A

some cleaning products and potassium soaps

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13
Q

Calcium hydroxide properties and use:

A

Addition of water to calcium oxide
Milk suspension - 20% surfaces, non spore forming bacteria, bactericidal on acid resistant mycobacteria
CaO lime: 3%, soil, slurry and manure - corrosive to zinc, aluminium and tin

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14
Q

Ammonium hydroxide is used for:

A

coccidia oocysts

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15
Q

Focal disinfection means?

A

Eradication of pathogens at the focus of infection, to interrupt disease transmission

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16
Q

Stages of disinfection in focal disinfection:

A
  1. Preparatory work
  2. Disinfection
  3. Mechanical cleaning
  4. Deactivation
  5. Test of efficiency of disinfection
  6. Finishing work - protocol
  • continuous or final
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17
Q

Methods of rodent control:

A

Mechanical: traps
Physical: sounds or water
Biological: cats and dogs - to reduce population
Chemical: rodenticides (acute, sub-acute, chronic)

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18
Q

Continuous disinfection must be performed continually during:

A

shedding pathogenic agents from sick animals into environment, will be repeated during the disease process and continue with final focal disinfection

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19
Q

Iodonal compounds properties:

A

Many preparations both aqueous and alcoholic based
Bactericidal
Mainly skin disinfectants
Never used on surfaces
Bactericidal
Low solubility: can be irritating to the skin, stain fabric, damage rubber, corrosive

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20
Q

Microbiological abilities of iodonal compounds:

A

Denatures proteins and interferes with the enzymatic systems of microbiological agents

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21
Q

Iodonal compounds:

A

Iodonal A
Iodonal B
Iodonal M

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22
Q

Iodonal A:

A

Works better in acidic environment
Veterinary practices and food industry
Used with phosphoric acid: 1.76% active iodine + 12.5% phosphoric acid
Preventative 2-4%
Focal 5-6%

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23
Q

Iodonal B:

A

Works better in acidic environment
Used in health service and public utilities
1.66% active iodine

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24
Q

Iodonal M:

A

Also contains glycerine and citric acid - protection of the mammary gland
Used in milking process - teat dipping
Treatment of udder 2-4%
Teat dipping 20%

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25
Q

What are the causes and consequences of eutrophication?

A

Eutrophication is the enrichment of water with nitrogen and phosphorous which causes the excessive growth of algae and phytoplankton

Causes: animal waste, fertilisers and sewage

Consequences:
* Changes in water turbidity and O2 levels
* Overgrowth of algae
* Precursors of trihalomethanes (human carcinogens potential)
* Higher presence of dissolved organic substances and the presence of more particulates
* Changes in dissolved oxygen
Phytoplankton can produce neurotoxins, hepatotoxins, cytotoxins, endotoxins

26
Q

Chemical properties of drinking water, limits and impact on organism:

A

Ammonia
Nitrites (NO2)
Nitrites + amines = nitrosamines - potential carcinogens
Nitrates (NO3)
Chlorides
Iron
Phosphates
Active chlorine
Chemical oxygen demand
Water hardness (Ca + Mg)
Dissolved oxygen
Conductivity
pH

27
Q

Nitrates in water:

A
  • Max limit 50 mg/L in adults, 15 mg/L in infants
  • Methemoglobinemia - blue baby syndrome
  • Acceptable amount in babies 3-6 months 4-6 mg/kg
  • Acceptable amounts in adults 350 mg/L
28
Q

Nitrites (NO2) in water:

A
  • Unstable - NO3
  • Max limit 0.1 mg/L
  • Fresh fecal contamination
  • Methemoglobinemia
  • Dangerous for children 1-10 mg
  • Dangerous for adults 500 mg
29
Q

Ammonia in water:

A
  • Max limit 0.5 mg/L
  • Fresh faecal solution
  • Contributes to eutrophication (algae formation)
30
Q

Chlorides in water:

A

Max limit 250 mg/L
Urine pollution
Irritation of nose, eyes, throat
Chest pain and difficulty breathing

31
Q

Iron (Fe) in water:

A

Max limit 0.2 mg/L
Changes in appearance, taste and colour
Stomach pain, nausea, v+, constipation

32
Q

Phosphates in water:

A

Max limit 1 mg/L
Indicates urine or fecal pollution
High algae, low dissolved oxygen, kills fish

33
Q

Active chlorine in water:

A

Max limit 0.05-0.3 mg/L
Risk of production of Trihalomethanes (THM) - potential carcinogens
Irritation to nose, eyes, throat and chest pain

34
Q

Chemical oxygen demand in water:

A

Max limit 3 mg/L
The amount of organic substances present in water that are oxidisable by strong oxidants under standard conditions
Indication of the likeliness of THM formation - carcinogens

35
Q

Water hardness (Ca + Mg):

A

Range 1.1-5 mmol/L
Not considered a public health concern
Changes the taste and makes the water unsuitable for use in food production industry

36
Q

Dissolved oxygen in water:

A

Recommended saturation >50%
The amount of oxygen in water
More of a concern to aquatic communities and ecosystems

37
Q

Conductivity of water:

A

Ideal 120 mS/m
Incorrect pH may indicate disturbance of relative condition of water

38
Q

pH range of water and consequences:

A

6.5-9.5
Incorrect - possible carcinogen and cardiovascular disease

39
Q

What are the differences between preventive and focal disinfection?

A

Preventative: mechanical cleaning is carried out after removal of manure, all organic matter and dirt from animal houses
Focal: manure and organic matter must be disinfected before it is removed from the house

40
Q

Methods used for mechanical cleaning:

A

Mechanical methods
Hot water under pressure
Detergent (soda)
Up to 90% of microorganisms are removed from the environmen

41
Q

Factors affecting the effectiveness of disinfection:

A

Resistance of microorganisms
Effect of disinfectant
Character of the environment
Temperature of disinfectant and environment
Concentration of solution
Quantity of used disinfectant
Exposure time
Number of application of disinfectant solution

42
Q

Development of resistance in rodent control is caused by:

A

Repeated use of the same rodenticide and is more common with chronic rodenticides
Common in multidose rodenticides

43
Q

What is secondary poisoning and how to prevent it?

A

Secondary poisoning occurs when an untarget animal ingests a rodent or another animal with undigested bait in the stomach or the mouth

Prevention:
Pulsation method - repeated placement of small amounts of bait repeated for 6-7 days so that the singel amount is not enough to kill untargeted animal
Quantities for this in rats is 20-80g, mice is 5-25 g

44
Q

Name methods for disinfection of drinking water:

A

Active chlorine (risk of THM formation)
Disinfection with ClO2
UV radiation
Ozone

(Ozone and ClO2 may degrade some pesticides = more toxic)

45
Q

Chemical rodenticides characterization:

A

Risk of resistance development
Aim to kill harmfull rodents
Use of bait materials similar to feed
Single or multidose
Acute, sub-acute or chronic

46
Q

Acute rodenticides:

A

Death in 6-24 hours
Rapid acting
Only once a year (very toxic)
Requires pre-baiting of 2-3 days
Bodies seen

  • Zinc phosphide: form lethal hydrogen phosphide with HCl in stomach
  • Aluminium phosphide: mainly in holes. Heart, liver and kidney damage
  • Red quill: CNS, emetic (rats cannot vomit). Silmurin-Microbil, Norbromide, Alphachlorase
47
Q

Sub-acute rodenticides:

A

Death in 3-6 days
Vitamin D preparations
Causes hypervitaminosis - changes in Ca metabolism - Ca from bones into bloodstream - heart attack and death
Slovtox, Calcitox, Quintox

48
Q

Chronic rodenticides:

A

Death in 4-10 days
Anti-coagulative effect
Change in blood coagulation
Vit K1 is antidote
1. Warfarin: Kumatox, ratio 1:19, resistance development
2. Superwarfarin:
- Brodifacoum (0.005%) Talon, risk of secondary poisoning
- Bromidalone (0.005%) Lanirat. 10-11 g, Storm (flucoumafen), Ratak (difenacoum)
3. gen: Difethialon, Baraki (0.0025%), Granulated toxic bait
reduced secondary poisoning, no bait shyness, antidotes available, slow action, bodies aren’t seen

49
Q

Indicators of hazards of drinking water:

A

Enterobacteriaceae
E. coli
Enterococci
Limits in mass supply: 0 in 100 ml
Individual supply: 0 in 10 ml

50
Q

Indicators of drinking water, methods of determination:

A

Enterobacteriaceae:
- Membrane filtration
- Specific agar: endo agar at 37 degrees for 24 hours
E. coli:
- Membrane filtration
- Specific agar: 43 degrees for 24 hours
Enterococci:
- Membrane filtration
- Specific agar: Slatnez-Blaney at 37 degrees for 24 hours

51
Q

Chloride compounds:

A

Doesn’t work as well if organic matter is present
Works on G- and G+ bacteria, viruses and spores
Affects permeability of the outer cell membrane, oxidation, fat oxidation, changes in pH, destruction of enzymatic system

Hypochlorites
Chloramines

52
Q

Chloride compounds - types:

A

Hypochlorites:
* Sodium hypochlorite
– Dairy industry and farm buildings
– Unstable - prep fresh
– Active chlorine 15% (min) + NaOH (0.6%) + NaCl (2%)
– Preventative 2-3%
– Focal 4-10%
* Chlorinated lime: CaClOCl -.calcium hypochlorite
– Powder
– Mix of hypochlorite, oxide and Ca hydroxide
– Unstable
– 33-36%, min 15%
– Preventive 2-3%
– 5% to devitalise spores and mycobacteria
Chloramines
– Stable, 25-30% active chlorine
* Chloramine T
- Bactericidal, virucidal, sporicidal
- Preventive 2-3%
- Spores 10%
* Dikonyt
- Surface sprays
- 55-60% active chlorine
- Activation at 50-60 degrees
- Devitalise spores and mycobacteria

53
Q

Formaldehyde preparations mechanism of action, properties and using:

A

Aldehyde disinfectant
Effect on enzymatic systems, denaturation of proteins, disrupt nucleic acids
Unstable 38-40%, min 30%
Liquid, vapour, gas
Lethal to: bacteria, viruses, fungi, spores, mycobacteria
No disinfectant effect under 15 degrees
Spray form comes in 2% or 10%
Aerosol: 25 ml/m3 (ET: 6 hours or overnight)
Vapour: inactivates viruses, spores, fungi, non-spore forming bacteria, needs humidity of 70-90%
Alkaline formalin: 3% + 3% NaOH - spores and mycobacteria
Carcinogen and mutagen

54
Q

Pyrethroids method of action:

A

Derived from pyrethrun
Sodium channel modulator, disrupts axonal transmission, continues nerve impulse transmission - tremor and death
Rapid killing effect

55
Q

Pyrethroids products:

A

Allethrin, Esbiothrin, Permethrin, Deltamethrin, Cypermethrin

56
Q

Pyrethroids use and advantagses:

A

Rapid killing effect
Very low toxicity to mammals and birds
High toxicity to fish and bees
Degraded rapidly in soil
Not active against mites
Safe to use in public health and industrial pest control, timber protection, mothproofing, grain protection, horticulture and agricultural crop protection

57
Q

Inorganic acids properties:

A

Highly corrosive
Strongest disinfection
Act on G- and G+ bacteria, viruses and fungi
MOA: dehydration, oxidation, change in pH, increased permeability of cell membrane, disruption of enzymatic system, denaturation of proteins

58
Q

Inorganic acids preparations:

A

Hydrochloric acid:
- Skin disinfectant (antrax spores)
- ET: 40 hours
Sulphuric acid:
- Combination with cresol
- Focal disinfection: ratio H2SO4: Cresol = 1:3
- Active on TBC and clostridium
Nitric acid (HNO3):
- for bacteria and spores in the food industry (milking equipment)
- concentration 0.3-0.5%
Phosphoric acid:
- H3PO4
- Used for manure and soil
- Concentration 1.5-3%

59
Q

Unstable disinfectants:

A

The concentration of active ingredient changes with time, environmental temperature etc.
Chlorinated lime
Persteril
Formalin

60
Q

Unstable disinfectants uses:

A

Chlorinated lime: 33-36%, min 15%, non-stable during storage, spraying form

Persteril: 32-36%, min 15%, stability depends on temperature (high accellerate decomposition), spraying or aerosol

Formalin: 38-40%, min 30%, liquid/vapour/gaseous forms, carcinogenic and mutagenic

Protection of the environment... (2 decks)

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