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14 Cards in this Set
- Front
- Back
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6 types of infectious agents |
Viruses Becateria Fungi Prions Protozoa Parasite |
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Characteristics of virus |
- no organelles - obligate intracellular pathogens (can only replicate inside living host cells ,unable to generate own ATP ,unable to translate mRNA into protein ) - described as "genetic material (DNA /rNA) inside a protein capsid (may contain lipid membranes or carbohydrates on surface) I |
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Different ways virus can become transmited |
Respiratory- influenza viruses (chickens), Rhinovirus (humans) Faecal-oral- enterovirus (pigs cows), provirus (dogs) rota virus (cattle) Body fluid - feline immunodeficiency and leukemia Sexual transmission- HiV, hepatitus Vectors- rabies,fellow fever |
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Process of viral infectiokn |
Attahcemnt to receptor- penetration / passes into cells- virus uncoats(capsid is shed)- takes over cells genetic machinery to / synthesis own viral mRNA, viral protien to make new capsid and viral neclic acid - assembly(capsid forms around nucleic acid) - release (viruses more out of cell (budding +envolope around virus ) or cytolysis (no envolope) |
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Feline leukemia virus |
Oral feacal transmission - affects all species of cat- clinical signs (tummors, immunosuppressiom, protien deposits in eye,blood disorders)- oncogenic |
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Rinderpest |
Symptoms - depression,diarrhoe, dehydration, death - affects all cloven hover animals - used as biotrroist weapon Asia - direc transmission from secretions - diverged and related the measles and canine distemper virus |
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Canine provirus - |
Affects- dogs cats foxes Spread - feacal-oral . Characterised by - haemorrhagic enterius (bloody diarrhoea)- infects by rapidly dividing in lymph node and crypt epithelium of intestinal villi Highly resistant in envieonerment |
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Characteristics of bacteria |
Free living - can survive and reproduce (rapid -double in number every 20 mins) without a host Single celled Treated with antibiotics Different shapes - rods, cocci, spiral Can be gram positive or gram negative |
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Difference between gram positive and gram negative bacteria |
Negative - thin peptidoglycan layer- crystal violent stain not retained(cells look pink ) Positive - thick peptidoglycan layer- stain retained (cells look purple) |
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Examples of gram positive bacteria and diseases they cause |
Clostridium - gasto-interstianal pathogen - no clinical signs - horses and chickens(often fatal) Mycoplasma- cattle pneumonia- hard to treat- rapid spread- antibiotics infective Mycobacterium - bovine and human tb- notifiabledisease- difcults to treat Staplylococcus and streptococcus- causes mastitis - infection of udder - big issue on milk farms |
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Examples of gram negative bacteria and disease it causes |
Gram negative bacilli- kennel cough (brochiseptica) -Cat scratch fever - zoonotic
Spirochetes- treponema - lameness on farm animals
Rickettsia- spread by ticks- can lead to paralysis and death Cocci- oval shape - Chlamydia- replicates in cytoplasm Fungi - largest life form on earth -forms spores- only infects areas where spores can get - surface,eyes,lungs,UTI- needs anti-fungal medicine - ie- candida- skin infeftiok in dogs common in those with folds- thrush in animals Ringworm- zoonotic- selflimiting- cures itself - In wildlife- fungus lives on skin of amphibians- prevent for breeathig
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What are prions What are prions |
Infectious protein that effects the brain - forming rafts which hold water and other materials-causes damage - no treatment usually fatal Ie- scrapie- alters behaviour - cause them to itch - loss of coat-. Lead to secondary infection - notifyable diseas Bovine spongiform-singlw gene crossover from sheep(scrapie) to cows by ingestion- increase cattle aggression and leads to lameness -notifiable |
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Examples of parasites and diseases they cause |
Multicellular organisms - two forms - ecto parasites - live on skin (fleas,ticks) - endo parasites- inside body. Myiasis - infection with maggots usually ectoparasites - but if ingested eat insides (intestinal myiasis) Taenia- pig tapeworm I causes brain cysts in humans |
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Examples of protozoa and diseases they caus e |
Single celled - free living organism Spread by vectors - common ly associated with neural and gastrointestinal infections ie neospora- causes paralysis in dogs and abortion in cattle , coccida- GI of chickens, regularly fatal, reduces productivity One of biggest killers- malaria |
