EPI 2 Flashcards
Salmonellosis in humans, how many are contributed to a source, what type of salmonella most commonly involved
- 54 /100,000 people per annum
- ~93% cases are not attributed to a source
- Salmonella Typhimurium
- 48% of human cases
What are the 2 main hazards associated with eggs and describe
- Microbiological
- Salmonella spp. - Chemical and Physical
- Agricultural and Veterinary Chemicals
- Feed and food Additives
- Plant, fungal and feed toxins
- Processing aids
What are the main differences in chicken industry structure between meat and egg industry and how many males to female ratio
- Chicken Meat Industry
- Vertically Integrated
- Produce chicken meat for human consumption - Chicken Egg Industry
- Independent Farms
- Produce eggs for human consumption
1 male: 10 females
What are the different stages/structures in poultry industry
Breeding Stock - Primary Breeding Companies Poultry Company Structure - Breeder Rearing* - Breeder Production* - Hatchery* - Broiler or Layer Production - Processing Eggs or Meat - *Feed Mills
What are the 2 main types of transmission of salmonella in poultry
1) Horizontal transmission Oral – faecal
2) Vertical transmission – true or paravertical
○ True vertical - via ovarian contamination of white or yolk
○ Paravertical – via infection egg shells
List some clinical signs and postmortem lesions of salmonellosis of poultry
Clinical Signs - Clinical presentation varies depending on: - Age at infection, dose, serotype and strain - May be absent - Pasted vent - Depression, anorexia - Stunting Postmortem lesions - Pericarditis, perihepatitis - Unabsorbed yolk sac - Focal necrosis in liver - Enteritis
What are 7 main sources of salmonella in chickens
- People
- Pest animals/insects
- Equipment
- Sheep - carryover
- Bedding material
- Feed
- Live birds
What is the most important source of salmonellosis in poultry, what occurs
- Primary source of many Salmonella spp. serotypes
○ Not Salmonella free - Contamination is not evenly distributed within feed
- Evidence that plants actively infected with Salmonella spp.
- Farmers have little control over feed quality
- Sampling is difficult
On farm sampling what is involved
- Shed Design influences the way we sample
- Environmental samples reflect flock infection
○ But may also be carry over from previous flock - Sample types include
○ Boot swabs
○ Dust swabs
○ Manure /mamure belt swabs
○ Egg belt swabs
○ Litter
What is some prevention and treatment of salmonella in poultry
Prevention - Identification of infected flocks - Culling of infected breeding flocks - Vaccination Treatment - Antibiotics may be used ○ But contra-indicated
Vaccination for salmonella in poultry what are the 2 types and what does it actual do
1) Modified live vaccines ○ Poor at best ○ Spray or oral drinking water 2) Killed vaccines ○ Autogenous ○ Proprietary ○ Intramuscular - Used in combination to provide longer duration of immunity and protection - Reduce duration and quantity of Salmonella spp. shed but do not prevent infection or shedding
Farmers responsibility what must we and what we must not do
Must
- Ensure premises, equipment and transportation
○ Constructed to minimise contamination of eggs
○ Kept clean, sanitised and in good repair
- Not supply eggs from birds affected by disease making eggs unsafe or unsuitable
- Identify and control safety hazards
- Ensure feed is not contaminated
Must NOT
- Sell eggs unless each egg is marked with producers ID
- Sell liquid white or yolk unless it is processed
What are the 3 things that lead to unacceptable eggs
a) a cracked egg or a dirty egg; or
b) egg product which has not been processed
c) egg product which contains a pathogenic microorganism, whether or not the egg product has been processed
What are 5 main ways for farm salmonella control
1) vaccinate flocks
2) depopulate infected flocks -> replace with non-onfected flocks clean and disinfect sheds
3) wash eggs - don’t wash inside, cross-contamination is possible with this process, water temperature needs to be higher then inside to keep water out
4) pasteurise all eggs from the flock
5) cangle - remove cracked and dirty eggs
Egg pasteurization does it occur in australia, why, what is needed
- Small number of organisations in Australia
○ Whole Egg pasteurisation in USA routinely
○ Not in Australia - Little demand
- Poor availability
- Egg and Egg Products is the only thing that is done in Australia -> not whole egg
- Reduction is time, temperature and dose dependent
○ 60 degrees for 3 minutes - Nothing is perfect
What are the 4 main factors that impact food system resilience
- Unprecedented loss of biodiversity (and thus less resilient ecosystems)
- Emergence of new infectious and non-infectious diseases
- Climate change, weather variability and rising ambient temperatures globally
- Increasing human population
What is important in terms of food security for the world and define
THEREFORE NEED A MOVE FROM JUST FOOD SECRUITY TO FOOD AND NUTRITION SECURITY
Definition
- When all people at all people have physical, social and economic access to food, which is consumed in sufficient quantity and quality to meet their dietary needs and food preferences, and is supported by an environment of adequate sanitation, health services and care, allowing for a healthy and active life. (CFS 2012
Non-communicable disease what is happening
- Growing concern for animal and human health and wellbeing
- Frequently related to poor dietary choices or formulations
- Associated with food loss and waste
Emerging infectious disease what are the 3 things that their evolution is facilitated by and the main pathogen involved
- Most are viruses, especially RNA viruses
Pathogenic evolution facilitated by - Increased host population density
- Increased genetic uniformity of host
- Population increased contact rate between hosts
Evolution of avian viruses what are the 3 things they are facilitated by
- Host genetic homogeneity
- High density rearing - close to close animal to animal contact and favouring transmission of virulent over low pathogenic strains
- Intensive vaccination programs - provide selective immune pressures and may be executed improperly in resource poor settings
List 3 diseases that have emerged in poultry and 3 in pigs from intensive products
Poultry - Avian influenza - Newcastle disease - Diseases of increasing virulence -> Marek's disease Pigs - Classical swine fever - Porcine reproductive and respiratory syndrome - Influenza A subtype H1N1
Impact of HPAI (H5N1) pandemic what has occurred in terms of animal death and economic losses
- Millions of poultry were slaughtered to control the spread of disease
Ø 50 million domestic birds slaughtered in Vietnam alone
Ø Widespread culling of family poultry impacted on vulnerable households
○ Increased stunting in children <5 years in Egypt
Ø Economic losses in SE Asia totalled around US $10billion -> direct and indirect effects on food security
○ Some farmers loss of all animals with zero compensation
Give some examples of non-communicable diseases
- Head, lung, liver, kidney and digestive tract disease
- Diabetes
- Cancer
- Arthritis
- Degenerative central nervous system disease
- Genetic disorders
- Autism
- Mental illness
What is the focus of global nutrition
- Interrelationships between farmers, gatherers, traders, regulators, consumers and policy-makers
- Contributions to the sustainable production of animal source foods through biosecurity, animal welfare, animal health and production and environmental impact assessments
What are the 4 definitions of emerging infectious disease and give an example for each
1) infectious disease where incidence has increased
Eg - tuberculosis
2) infectious disease where the geographical distribution has changed
Eg - west nile virus
3) evolving infectious disease - old with new host (equine influenza in dogs) OR old with new presentation (Zika virus)
4) New discovered infectious disease (lyme disease caused by tick-borne borrelia)
Define a reservoir, what are they needed for
- an ecological system in which the infectious agent survives indefinitely
- Reservoir hosts are essential to the maintenance of the pathogen.
- Without the reservoir host, pathogens would disappear, along with the disease that they cause.
what are the 3 main phases of virological discovery for bats
1) when scientists first identified a link between bats and viruses
2) when scientists went into the forest
3) when bats came out of the forest - hendra
