Parasitology Exam 2 - Resistance Flashcards
Factors that contribute to development of anthelmintic resistance
*frequent use of drugs of the same group
*anthelmintics in sub-optimal doses
*prophylactic mass drug administration/intensive use
*frequent, continuous use of single drug
genetics
innate/acquired immunity
age & maturity
refugia
in GI nematodes with direct life cycles, when does this increase
the proportion of a population not exposed to a drug, thus escaping selection for resistance
-life stages are unaffected
-some parasites left untreated
-free-living stages exist in the environment
Some practices that might be incorporated into sustainable parasite control program
parasite resistant breeds
nutrition
pasture management
antiparasitic vx
botanical deworms
all reduce use of chemicals and are environmentally friendly approaches
Reasons that an animal may have a seemingly refractory response to treatment
co-infection
reinfection
biological reasons
innate resistance
species-specific resistance
age-related resistance
+/- breed related resistance
acquired resistance
dependent on Ag stimulation and humoral/cellular responses
few vaccines exist against parasites diseases
natural expression
sheep over 3 months are resistant to _________
Nematodirus Battus
dogs over 1 year develop resistance to ______
Ancylostoma
how can anthelmintic resistance be prevented in cattle
treating with two classes
monitor egg counts
treat when eggs reach a pre-set level
small animals’ resistance to _______ due to which antihelmintic?
Dipylidium caninum
Praziquantel
_____ resistance in small animals
Dirofiliria immitis or Giardia
______ have anthelmintic resistance in cattle
Strongyles –> “Haemonchus contortus “barber pole worm”
____ genera may potentially be associated with anthelmintic resistance in ruminants
Cooperia spp. to Macrocyclic lactones
