Chap 9- PRINCIPLES OF LIVESTOCK, FISHERIES DISEASE PREVENTION, CONTROL AND PUBLIC HEALTH Flashcards
What is the definition of disease?
Any structural or functional deviation from the normal in the system of an animal
Define communicable disease
An illness due to a specific infectious agent or its toxic products which can be transmitted from an infected host to a susceptible host either directly or indirectly
What is an allergen?
A specific substance that causes hypersensitivity (allergy) when inhaled or contacted with the body (e.g. hay pollen dog/cat hair particles horse/cow/sheep dandruff)
What is the communicable period?
The time during which an infectious agent may be transferred from an infected individual to another person/animal
Define incubation period
The period between contacting a disease agent and the time the disease shows itself clinically
What is epizootiology?
The study of the occurrence and spread of disease in populations in order to control it
What is case fatality rate?
The number of people that died per 100 cases of a disease
Define carrier in disease context
An infected individual that harbors a specific infectious agent without showing clinical disease and serves as a potential source of infection
What is an antigen?
A substance capable of inducing specific immune response (e.g. Yellow fever vaccine)
What are fomites?
Inanimate objects or personal articles that can transmit infectious agents (e.g. handkerchief drinking glass clothing toys)
Define isolation in disease control
The separation of infected persons/animals from others during the communicable period to prevent disease transmission
What is cyclicity in disease patterns?
Seasonal recurrent alterations in disease frequency implying a link between disease cause and seasonal aspects
What is etiology?
The study of the causes of a disease
Define prognosis
The outlook regarding the outcome of an illness (e.g. complete recovery partial recovery or death)
What is a pathogenic agent?
An agent usually infectious that is capable of causing disease
What is herd immunity?
The resistance of a group to invasion/spread of an infectious agent based on high proportion of immune individual members
Define complete quarantine
Limitation of movement for exposed persons/animals for duration not longer than the longest incubation period of the disease
What is prophylaxis?
Prevention or preventive actions taken prior to the onset of disease
Define chemotherapy in disease context
The use of chemicals to cure a clinically recognizable infectious disease or limit its progress
What is chemoprophylaxis?
Administration of chemicals including antibiotics to prevent infection development or progression
Define infestation
The lodgement development and reproduction of arthropods on body surface or clothing
What is an immune individual?
A person/animal with specific protective antibodies/cellular immunity from previous infection or immunization
What is disease prevention?
The application of measures to exclude diseases from an unaffected population (first line of defense)
What is disease control?
Measures directed at reducing existing disease frequency to a level without significant public health/economic consequences
Define disease eradication
Efforts directed at eliminating disease agents from a geographical area
List main reasons for disease prevention
1) Prevent mortality 2) Maintain productivity 3) Prevent disruption of herd structure 4) Protect public health
What are the three common methods of disease transmission?
1) Contact transmission 2) Vehicle transmission 3) Vector transmission
What is direct contact transmission?
Physical contact between infected and susceptible individuals
What is indirect contact transmission?
Contact through fresh secretions or aerosol droplets between infected and susceptible individuals
What is vehicle transmission?
Transmission through inanimate substances like feed water dust and equipment
What is vector transmission?
Transmission by invertebrate animals carrying infectious agents between vertebrates
What are key aspects of good husbandry practices?
1) Stock disease-free animals 2) Isolate new animals 3) Maintain adequate ventilation 4) Avoid overstocking
How can host resistance be modified?
Through genetic resistance transfer of passive immunity and stimulating acquired resistance (e.g. vaccination)
What is the purpose of quarantine?
To enforce physical separation of infected/potentially infected animals from healthy population
What role do chemicals play in disease control?
Used for disinfection pest control and treatment (antibiotics anthelmintics etc)
What is biological control in disease management?
Using living organisms to control disease agents vectors or reservoir populations
Why is extension education important in disease control?
Helps educate farmers/public about disease recognition prevention and control measures
What causes mastitis in cattle/sheep/goats?
Infectious agents like Streptococcus beris S. dysgalactiae and Corynebacterium pyogenes
How can mastitis be prevented?
1) Treat affected animals 2) Cull chronic cases 3) Dip teats after milking 4) Maintain hygiene
What causes tetanus and its symptoms?
Caused by Clostridium tetani symptoms: limb stiffness muscle tremor lockjaw hyperesthesia
How is salmonellosis prevented?
1) Prevent carrier animals 2) Avoid contaminated food 3) Disinfect farm 4) Prevent water contamination
What is liver fluke disease and its symptoms?
Caused by Fascioloides/Dicrocoelium symptoms: weakness loss of appetite weight loss bottle jaw
What causes hookworm disease and its effects?
Caused by Bunostomum species effects: poor growth blood loss anemia abdominal pain
What is foot and mouth disease?
Highly contagious disease with fever and vesicular eruptions in mouth/foot affects cloven-footed animals
How is rinderpest prevented?
1) Periodic vaccination of susceptible livestock 2) Complete elimination of affected animals
What is Kata disease?
Acute viral disease in goats/sheep with fever loss of appetite nasal discharge respiratory distress
What causes trypanosomosis and its symptoms?
Caused by Trypanosoma species symptoms: intermittent fever dullness swollen lymph nodes
What are key effects of rodents in farms?
1) Disease spread 2) Building damage 3) Grain consumption/spoilage 4) Harm to livestock
How can rodents be controlled?
1) Sanitation 2) Physical methods 3) Biological control 4) Electric devices 5) Chemical control
What is the all-in-all-out system?
A husbandry system ensuring new stock has no contact with old potentially diseased stock
Why is environmental hygiene important?
Most diseases result from ecological imbalance reducing severity through improved ventilation lighting and cleaning helps prevent disease
What factors are important in fish health management?
Water quality temperature dissolved oxygen nitrite levels turbidity alkalinity and carbon dioxide concentration
How does vaccination work?
Inoculation with living/dead antigenic preparations to protect against specific diseases
What is selective slaughter in disease control?
Killing of test-positive animals after immunological screening to prevent disease spread
What are important water parameters for fish health?
Temperature dissolved oxygen nitrite concentration turbidity alkalinity carbon dioxide levels
When should new animals be quarantined?
When introduced to a farm to ensure they’re disease-free before mixing with existing stock
What is the role of veterinary extension services?
Educate farmers/public about disease recognition prevention and control methods
How does stress affect disease susceptibility?
Increased stress reduces animal resistance making them more susceptible to infections
What is zoonotic disease?
Diseases that can be transmitted between animals and humans
Why is antibiotic resistance a concern?
Due to misuse in humans/animals leading to reduced treatment effectiveness
What is passive immunity?
Immunity transferred from mother to offspring through colostrum
What is active immunity?
Immunity developed by an animal through exposure to disease/vaccination
How does herd structure affect productivity?
Disease-related deaths/culling can lower productivity by preventing animals from reaching full potential
What are transboundary animal diseases?
Diseases that don’t respect geographical boundaries requiring global surveillance
Why is colostrum important for newborns?
Provides passive immunity within first three days of life
What organizations monitor global animal health?
WHO OIE and FAO
What is the purpose of disease surveillance?
To monitor detect and respond to disease outbreaks
How do vectors transmit disease?
By carrying infectious agents between vertebrate hosts either mechanically or biologically
What is mechanical transmission?
Physical transfer of disease agents without agent development
What is biological transmission?
Transfer of disease agents with further development/multiplication in the vector
Why is proper ventilation important?
Reduces aerosol disease transmission in intensive housing systems
How does overcrowding affect disease spread?
Increases stress and contact between animals facilitating disease transmission
What is the importance of water quality in fish farming?
Poor water quality can stress fish making them more susceptible to disease
Why are drug residues a concern?
Can affect human health through consumption of animal products
What is stamping out in disease control?
Complete depopulation of infected/exposed animals to prevent disease spread
How do disinfectants help prevent disease?
Reduce or eliminate infectious agents in the environment
Why is public health education important?
Helps reduce economic/social impact of epidemic diseases especially zoonoses
Front
Back
What is the definition of zoonoses according to FAO/WHO?
Diseases and infections which are naturally transmitted between vertebrate animals and man
What percentage of human infections are traceable or suspected to be zoonotic?
Over 80%
Name the three types of myiasis based on body areas affected.
1) Cutaneous myiasis 2) Myiasis in cavities of the body 3) Tissue myiasis
What are the two types of myiasis based on host dependence?
1) Facultative myiasis (larvae are free living) 2) Obligatory myiasis (larvae are dependent on host)
What is brucellosis also known as?
Undulant fever, Gillbrata fever, Bang’s disease (in cattle), Mediterranean fever
What are the two main species of Brucella that affect humans?
Brucella abortus (from cattle) and Brucella melitensis (from goat)
How is brucellosis transmitted to humans?
Through drinking unpasteurized milk, contact with tissues, blood, urine, and vaginal discharges of infected animals
What are the three clinical forms of anthrax in humans?
Cutaneous (skin form), pulmonary (respiratory), and gastrointestinal form
Which form of anthrax is most common in humans and what is its mortality rate?
Cutaneous form, with 5-20% mortality rate if untreated
What are the three types of Mycobacterium that cause tuberculosis?
M. tuberculosis (human TB), M. bovis (cattle TB), M. avium (bird TB)
What is botulism and what causes it?
A serious food poisoning caused by toxins produced by Clostridium botulinum
What are the main symptoms of botulism?
Extreme mouth dryness, weakness, blurred vision, double vision, vomiting, diarrhea, and nervous system problems
How long do botulism patients typically survive if untreated?
3 to 7 days due to respiratory or nervous system failure
What is Campylobacteriosis and what organisms cause it?
An enteric bacterial infection caused by Campylobacter jejune or C. fetus
What animals can serve as reservoirs for Campylobacteriosis?
Cattle, sheep, pigs, cats, dogs, and chicken
What is the shape of the rabies virus?
Bullet shaped
Name three areas that are currently free of rabies.
Australia, New Zealand, Japan
What is the typical incubation period for rabies?
2 to 8 weeks
What factors affect the rabies incubation period?
Severity of wound, site of wound, richness of nerve supply, distance from brain, amount of virus, clothing protection
How long before clinical signs can dogs and cats transmit rabies?
3 to 10 days
What is the observation period for a healthy dog or cat that has bitten someone?
10 days
What are the two types of yellow fever?
Cosmopolitan Yellow Fever (CYF) and Jungle Yellow Fever (JYF)
Which type of yellow fever is more dangerous?
Jungle Yellow Fever (JYF)
How is yellow fever transmitted?
Through the bite of an infected mosquito
What are the symptoms of yellow fever?
Cold, chills, liver damage, jaundice, weakness
Where was Lassa fever first discovered?
In Nigeria (Lassa village)
What is the reservoir host for Lassa fever?
Multimammate rat
How is Lassa fever transmitted?
Through contamination of environment by rat feces and urine
What age group is most at risk for monkey pox?
Children under 10 years
What causes sleeping sickness in West Africa?
Trypanosoma gambiense
What causes sleeping sickness in East Africa?
Trypanosoma rhodesiense
How is trypanosomiasis transmitted?
Through the bite of an infected tsetse fly (glossina)
What are the early symptoms of trypanosomiasis?
Sleeplessness, difficult breathing, altered vision, anemia, muscular pain
What is toxoplasmosis and what causes it?
A parasitic infection caused by Toxoplasma gondii
What animals serve as the definitive host for toxoplasmosis?
Cats
What are the risks of toxoplasmosis during pregnancy?
Can cause abortion, blindness, and deafness in newborn babies
How many species of flies belong to the order Diptera?
Many - it’s a large complex order
What characterizes most members of the order Diptera?
They have two wings as adults
What diseases can houseflies transmit?
They transmit diseases to farm animals through contaminated saliva
What disease does the tsetse fly transmit?
Trypanosoma gambiense and Trypanosoma brucei, causing sleeping sickness
What do fleas do to animals and poultry?
They suck blood and transmit diseases
What disease agents do cockroaches contaminate food with?
Salmonella, Clostridia, and Staphylococci
What do Ham and Hide beetles do to meat?
Create holes in meat, lowering economic value, and carry Clostridium botulinum spores
List five ways to control insects.
1) Destroy breeding sites 2) Control entry with screens 3) Control inside buildings 4) Use chemical insecticides 5) Biological control
What is a non-residual insecticide and where is it ideal for use?
Ideal for edible processing areas
What is Pyrethrium and what are its characteristics?
A plant extract insecticide with good knockdown effect and safety
What are five ways birds can cause damage?
1) Consume foodstuffs 2) Cause economic loss 3) Carry diseases 4) Affect comfort and power systems 5) Act as predators
How can birds be controlled?
Through proper husbandry techniques, trapping, shooting, and aerial spraying
What classifications can be used for zoonoses?
1) Aetiology 2) Reservoir Host 3) Infectious cycle
What are the types of zoonoses based on reservoir host?
Anthropozoonoses, Zooanthroponoses, Amphixenoses
Define direct zoonoses.
Transmission by contact or vehicle, requiring single vertebrate reservoir species
What are cyclozoonoses?
Diseases requiring at least two vertebrate species to complete infectious cycles
Define metazoonoses.
Diseases transmitted by invertebrate vectors and requiring intermediate hosts
What are saprozoonoses?
Diseases requiring organic or inanimate matter as a reservoir
Why do we study zoonoses? List three reasons.
1) Competition for food and water 2) Human consumption of vertebrate hosts 3) Keeping vertebrate hosts as pets
What are the symptoms of campylobacteriosis?
Severe abdominal pain, diarrhea, fever, vomiting, weakness
How is rabies typically transmitted to humans?
Through the bite of an infected animal
What should be done with unvaccinated dogs and cats bitten by rabid animals?
They should be destroyed immediately
What are the post-exposure prophylaxis steps for rabies?
1) Physical removal of virus through wound cleansing 2) Specific immunologic protection
How is yellow fever virus maintained in nature?
It circulates between forest monkeys and mosquitoes
What precautions should be taken to prevent Lassa fever?
Control rats, keep foods covered, clean drinking utensils
How does trypanosomiasis progress if untreated?
Progresses to weakness and sleeping sickness, followed by coma and death
What are three non-human primate malaria characteristics?
Transmitted by anopheline mosquitoes, cause low-grade fevers, can infect humans
Who is most at risk for severe babesiosis?
People who have had their spleen removed
How can toxoplasmosis be prevented in cats?
Regular veterinary check-ups, preventing cats from hunting rats
What is myiasis?
The migration of fly larvae in subcutaneous tissues or organs
What are common breeding sites for flies that should be destroyed?
Vegetation, rubbish, uncovered drains
What are residual insecticides used for?
Outside buildings, drains, and garbage breeding sites
Name three examples of residual insecticides.
D.D.T., B.H.C. (Lindane), Chloridane
What is the recommended Malathion solution concentration?
0.025-0.125%
What is the recommended concentration for Potassium sorbate solution against fungi?
5-10%
How can birds damage power infrastructure?
Woodpeckers can damage telephone and power poles
What disease can parrots transmit to humans?
Ornithosis
What animals do golden eagles commonly predate on?
Sheep and goats, especially newly born animals
How should anthrax-infected animal carcasses be handled?
They should be condemned at abattoirs by veterinary public health doctors
What are the symptoms of bovine tuberculosis in humans?
Cervical adenitis, spine inflammation, intestinal and bladder problems
What is the primary way humans contract tuberculosis from cattle?
By drinking contaminated unpasteurized milk
How should food be handled to prevent botulism?
Adequate cooking or boiling to destroy pathogens and toxins
What should you check for when buying canned foods like sardines?
Check for swollen tins which may indicate bacterial gas production
Why is spleen removal dangerous in relation to babesiosis?
It removes natural protection against the infection
