10 infectious diseases Flashcards
name 4 viral diseases
- Influenza
- Ross River virus disease
- Viral disease of honeybees (CBPV, DWV)
- Australian bat lyssavirus
name 3 bacterial diseases
- Tuberculosis (TB)
- Tetanus
- Crown gall of plants
name the 1 fungal disease
- Amphibian chytrid fungus disease
name the 2 protist diseases
- Malaria
- Jarrah dieback
symptoms of influenza
The virus attacks the respiratory system. Sudden onset of high fever, cough, muscle aches and pains, sore throat, runny nose. Usually lasts up to 2 weeks. incubation period of 1-4 days
Symptoms of ross river disease
rash on limbs or trunk for 5-10 days, painful and swollen joints, usually lasting for months, fever and headache. Incubation period of 1-3 weeks
symptoms of Chronic bee paralysis virus (CBPV)
Trembling wings and body, failure to fly, loss of hair. Incubation period varies
Symptoms of deformed wing virus
Wing deformity, can be asymptomatic. Incubation period varies
Symptoms of Australian bat lyssavirus
virus attacks nervous system, paralysis, delirium, convolutions/muscle spasms, death. Incubation period of 20 days - 27 months
Symptoms of Tetanus
Clostridium tetani. Sustained, severe muscle contractions due to blocking of nerve impulses by tetanus toxin. Incubation period 3-21 days
Symptoms of Tuberculosis (TB)
Persistent cough, coughing up septum or blood, fever/night sweats, steady loss of weight, fatigue. Incubation period of 3-9 weeks. Can stay dormant for months of years, called ‘latent TB’
Symptoms of Crown gall of plants
galls form on plant which can lead to stunted growth and wilting (because gall interferes with water and food transport). 8 weeks until gall becomes visible
Symptoms of Chytridiomycosis
Skin thickens and hardens. Respiration becomes difficult because significant gas exchange occurs across moist skin under normal conditions. The amphibian can become lethargic. Hind legs extend, and the amphibian becomes sluggish and has no appetite. These symptoms can lead to death. Incubation period of 2-10 weeks, death follows onset of symptoms within 2-3 days
Symptoms malaria
Fever, headache, chills (shaking), sweating and vomiting. If left untreated and host is susceptible, complications such as anaemia and liver failure can develop. Incubation period of 10-15 days
symptoms of Phytophthora dieback (jarrah dieback)
Areas of the plant appear rotten and may have lesions (where the pathogen has consumed the cell’s sugars). Wilting, root systems die (dieback), plant death follows. Incubation period ranges from weeks to months. Once wilting starts, death follows quickly
Influenza mode of transmission
Single stranded RNA virus
- Direct: close contact via airborne droplets when an infected person sneezes or coughs
- Indirect: fomites
influenza life cycle specifications
- Entry and exit: respiratory system
- Replication: inside epithelial cells in the respiratory tract
- Reservoir: Human host
Ross river virus disease mode of transmission
Single stranded RNA virus
- Indirect: Female mosquito vector
Ross river virus disease life cycle specifications
- Entry and exit: Two different blood feeds, exit not likely from human host, pathogen circulates through marsupials (eg western grey kangaroo)
- Replication: Epithelial cells of mosquito vector and muscle cells of the infected human host before entering the bloodstream and multiplying then
- Reservoir: Marsupials (eg wallabies)
Deformed wing virus disease mode of transmission
Virus
- Indirect: Vector varroa mite
- Direct: Vertical transmission from bee to offspring
Deformed wing virus disease life cycle specifications
- Entry and exit: Skin (blood feeds from varroa mite vectors)
- Replication: in bee
Australian bat lyssavirus mode of transmission
RNA virus
- Direct: Contact with an infected bat’s bodily fluids, through bite or scratch
Australian bat lyssavirus life cycle specifications
- Entry: Site of bite or other break in skin
- Replication: In bat reservoir and infected human host before travelling along nerves to CNS
- Exit: not likely from human host, pathogen circulates through marsupials such as the western grey kangaroo
Tuberculosis mode of transmission
Mycobacterium tuberculosis (Bacteria)
- Direct: close contact via airborne droplets inhaled into respiratory system
- Indirect: If droplets land on dusty fomite, become disturbed then inhaled
Tuberculosis life cycle specifications
- Entry: respiratory system
- Replication: in alveolar macrophages in lungs
- Exit: Respiratory system through cough or sneeze
Tetanus mode of transmission
Clostridium tetani (Bacteria) - Direct: contact between soil reservoir and deep puncture wound
Tetanus life cycle specification
- Entry: deep wound
- Replication: In tissue in a deep wound in the absence of oxygen, the neurotoxins travel up neurons, blocking the release of inhibitory neurotransmitters in the CNS
Crown gall mode of transmission
Agrobacterium tumefaciens (bacteria)
- Indirect: Soilborne spores via a root wound or gardening tools
- Direct: contact via infected root to wound on susceptible plant root
Crown gall life cycle specifications
- Entry: wound on susceptible plant
- Replication: In plant roots. Bacteria transfer some plasmid DNA into the plant cell genome, the inserted DNA codes for uncontrolled plant growth. Plant cells grow and divide and form galls
- Exit: Via galls, through spores that drop into the soil or onto tools for further spread
Chytridiomycosis mode of transmission
Fungus
- Indirect: soilborne/waterborne swimming zoospores
- Direct: contact via infected amphibian skin to susceptible amphibian skin
Chytridiomycosis life cycle specifications
- Entry: Skin penetration (invades outer layer of skin)
- replication: asexual reproduction inside the thallus (zoosporangium)
- Exit: zoospores going from the thallus in the skin of an amphibian into the water
Malaria mode of transmission
Protist
- indirect: Female Anopheles mosquito vector blood feeds
Malaria life cycle specifications
- Entry and exit: skin via blood feed by mosquito vector
- Replication: Sexual reproduction between male and female gametes in the mosquito gut (definitive host), asexual reproduction of sporozoites in the liver, asexual reproduction of merozoites in red blood cells (human is intermediate host)
Phytophthora mode of transmission
Protist
- Indirect: Swimming soilborne zoospores and via vechiles (car tyres, boots)
- Direct: contact between infected and susceptible roots and waterborne
Phytophthora life cycle specifications
- Entry: root tips, the mycelia threads grow on the surface and the invade the cells to gain nutrients and moisture for growth and reproduction
- Replication: on and in root cells, usually asexual, a few cells form a filament, filaments form mycelia threads and a mass of threads can develop into a sporangium
- Exit: Sporangia in the form of zoospores, if conditions are poor chlamydospores are produced instead (resilient forms of the organism), soil is a reservoir
3 biological issues related to management of influenza
- Viruses rapidly develop new strains
- Epidemics are seasonal (usually winter)
- Transmission is rapid in crowded areas of high host density
3 strategies of prevention and control of influenza
- Yearly vaccination
- Hand washing and washing of fomites
- Isolation
3 biological issues related to management of ross river
- No vaccine or cure
- Mosquito borne disease passing between animals and humans
- Vector transmission higher after rainy seasons that leave mosquito breeding habitats
3 strategies of prevention and control of ross river
- blood test for diagnosis
- personal protection (long sleeves, bed nets), prevention is key
- medical treatment to reduce joint pain and swelling
3 biological issues related to management of DWV
transmitted by varroa mite, not currently a threat in Australia
3 strategies of prevention and control of DWV
- regularly inspect bee hives for signs of disease
- quarantine
- pest management, may mean culling the hive
3 biological issues related to management of Australian bat lyssavirus (ABL) disease
- After onset of symptoms, mortality is usually 100%
- sick or injured bats are more likely to be infected and handled
- Habitat loss influences density, causing a higher rate of transmission between bats
3 strategies of prevention and control of ABL disease
- Vaccinate prior exposure and during incubation period
- wash wound immediately
- Do not touch bats
3 biological issues related to management of TB
- can remain suspended in air for prolonged periods
- extreme multidrug resistance
- easily spreads globally, spread by infected people travelling
3 strategies of prevention and control of TB
- Respiratory protective equipment
- Isolation
- cough into tissues
3 biological issues related to management of tetanus
- infectious but not contagious
- tetani spores found everywhere in environment
- neurotoxin causes infected host harm but not the bacteria
3 strategies of prevention and control of tetanus
- Vaccinate
- Booster vaccination throughout adolescence
- wash and disinfect puncture wounds, see doctor at once
3 biological issues related to management of Crown gall
- invasion of spores requires root wound
- transported via rain and runoff
- no cure
3 strategies of prevention and control of Crown gall
- Eliminate any plants with galls
- Treat tools with a disinfectant
- wash down tyres and boots before leaving contaminated area
3 biological issues related to management of Chytridiomycosis
- Climate change and UV radiation may be reducing resistance to infection
- Fungus is temperature sensitive, confined to cool wet areas
- vaccines are not effective
3 strategies of prevention and control of Chytridiomycosis
- Protecting uninfected areas
- identify and prioritise frog species at risk of extinction
- implement hygiene protocols (eg disinfecting vehicles)
3 biological issues related to management of Malaria
- breeding sites can form due to rainfall or flooding in unpredictable areas, hard to eliminate sites as quickly as they form
- Strains of the mosquitoes have evolved resistance to insecticides and anti malarial drugs
- spread is subject to distribution of specific species of mosquito vectors
5 strategies of prevention and control of Malaria
- Chemical incecticides to kill mosquito vectors and their larvae
- Eliminate stagnant water breeding sites
- avoid being outdoors when mosquitoes are most active (dusk and dawn), wear protective clothes during the day
- Biologoical control (eg mosquito fish) to feed on mosquito larvae
- Anti malarial drugs
2 biological issues related to management of Phytophthora
- Spores do not need a wound for entry
2. After symptoms appear death follows rapidly
3 strategies of prevention and control of Phytophthora
- Quarantine
- Sterilse/wash down tools, clothing, footwear, equipment
- destroy infected trees
