Tick Borne Diseases Flashcards
what are the vectors of most vector borne diseases
arthropods
- ticks, mosquitoes, fluke, lice, fleas
can vector borne pathogens exist outside of the vector or host
NO - obligate intra-host pathogens
can live in either definitive or intermediate hosts
what are the top clinical signs of vector borne disease in all hosts
fever
thrombocytopenia
what are the clinical signs and findings of vector borne disease in dogs
CS: fever, polyarthritis, vasculitis, myocarditis, glomerulonephritis, petechiae, GI bleeds
Labs: pancytopenia, thrombocytopenia, anemia
what are the clinical signs and findings of vector borne disease in cattle
CS: fever, CNS signs (hyperesthesia), peracute death, petechiae/ecchymosis
Labs: thrombocytopenia, hemolytic anemia, icterus
what are the clinical signs and findings of vector borne disease in horses
CS: fever, anorexia, depression, CNS signs (ataxia), vasculitis, petechiae
Labs: thrombocytopenia, icterus, anemia
what are rickettsial organisms
small bacteria that are:
- gram negative
- aerobic
- obligate intracellular
what are the two families and species of rickettsial organisms
- anaplasma: anaplasma, ehrlichia, neorickettsia
- rickettsia: rickettsia
characteristics of rickettsia
- obligate intra host and intracellular
- replicate via binary fission within phagosomes of infected cells
- form morula clusters
pathogenicity and clinical signs depend on cell target
what are rickettsial organisms treated with
tetracyclines
what diagnostics are used for canine ehrlichiosis
- serology: ELISA SNAP test, IFA
- PCR
- cytology: blood smear
what might cause false negative ELISA SNAP test
acute infections
double check with pCR
what diagnostics are used for heartwater
- cytology
- post mortem histopathology of CNS tissue
what diagnostics are used in anaplasma
- cytology
- serology: ELISA
- PCR
what mechanisms are used by intracellular pathogens to enter host cells
bind to host cell membrane receptors to facilitate transport into cells
what are some mechanisms that intracellular pathogens use to persist within host
- antigenic variation
- enzyme production - degrades phagosome to survive in cytoplasm
- hijacking host cell processes - using actin to transport and inhibiting apoptosis
what are mechanisms that intracellular pathogens use to evade host immune defenses
antigenic diversity - decreases ability of immune system to recognize and destroy the pathogen
allows for development of CHRONIC infections
what immune response do hosts mount to intracellular pathogens
strong HUMORAL response
- also requires cell mediated
antibodies target surface proteins on antigen
what virulence factors are used by intracellular pathogens
- endotoxin (LPS)
- stimulates immune complex formation (type III hypersensitivity)
- stimulates antibody production (type II hypersensitivity)
