Parasiticides and Parasitology Control Programs Flashcards
describe the general antiparasitic drugs commonly used in veterinary medicine (antiprotozoals, antihelmintics, insecticides, aracides) with emphasis on specific indications and selection
- endoparasiticide: kills internal parasites
- ectoparasiticide: kills external parasites
- endectocide: kills BOTH internal and external parasites; a new term coined specifically for avermectin/milbemycin (macrocyclic lactone) drugs
- antiprotozoals
- anthelmintics: nematocides, flukicides, cestocides; kills parasites but may not control them
- insecticides/acaricides: activity against ticks, mites, flies, fleas, lice; may be applied to animal OR environment
list and describe the 5 classes of anthelmintics
- benzimidazoles: bine to beta-tubulin and disrupts polymerization of tubulin into microtubules; broad spectrum, safe, but lots of resistance :(
- macrocyclic lactones: cause paralysis of pharyngeal and somatic muscles, but can cause blockage when a wad of worms die; effective against most nematodes and arthropods and safeish
- membrane depolarizers: depolarizing NM blocking agents cause spastic paralysis of worms; brads spectrum nematocides, most are very safe
- isoquinolone: MOA unknown but causes spastic paralysis of worms; effective against cestodes, some trematodes (not in ruminants), and safe
- cyclooctadepsipeptides: MOA unknown, new class
what is the main goal of most ectoparasiticides?
interfere with parasitic growth; some interfere with CNS or PNS, but most common is interfere with growth
what factors must be considered when formulating a control program?
they are all individualized!
- is the pet in a home or in a shelter or in a herd?
- what is the age/breed/repro status of the animal
- what is the environment?: housing, financial constraints, feasibility
- what are the client/owner goals?
- does the animal travel? does it have a job?
describe testing and treatment for client-owned small animal
testing:
1. for vector-borne parasites at least annually (heartworm: antigen + microfilaria in dogs, tick-transmited pathogens)
2. internal parasite testing AT LEAST annually (fecal diagnostics, increase frequency in young or risky animals)
treatment:
1. treat/give preventative to every pet all year long! even indoor only cats
2. repeat testing after treatment too!
what are the goals of testing/treatment in equine/production animals?
- minimize disease only! parasite eradication in every animal is impossible bc they eat where they poop
- herd-wide control puts heavy selection pressure on worm populations for drug resistance so:
-maintain refugia (proportion of the worm population NOT selected by drug treatment, only treat highest shedders, etc.)
-use drugs in combination
-integrate non-chemical modalities
describe 2 strategies to delay resistance in large animals
- targeted selective treatment: treat only those who need it, determine by fecal egg count (horses), diarrhea score, BCS, FAMACHA
- selective non-treatment: best method for cattle, treat only 80-90% of the herd and leave the heaviest loaded and best looking untreated to maintain refugia
contrast attributes of antiparasitic drugs, including information on use of drugs prophylactically and therapeutically
describe appropriate administration/application of drugs (PO, topical, injectable, etc.), off-label/extra-label/mino species use of these drugs. product withdrawal times in food animals, and issues of drug resistance
formulate control programs based on a knowledge of a parasite’s biology and the use of chemical and nonchemical methods of parasite control
develop a control or prevention plan to inform a client and/or the public about the risks of major parasites (including biosecurity, zoonotic potential, and food safety)
give 6 examples of ectoparasiticides; where are they used?
- insecticides
- acaricides
- repellents
- insect growth regulators
- insect development inhibitors
- synergists
many used in both pet and ag (crop) settings
macrocyclic lactones commonly used systemically; organophosphates used topically (ear tags) and environmentally (premise spray, foggers)
what ectoparasiticides go on the animal?
topical: spot-on, dip, sprays, shampoo, collars
systemic: oral, parenteral, topical
what ectoparasiticides are applied to the environment?
foggers, strips, premise sprays, dusts, powders
what must be taken into account when formulating use of ectoparasiticides? (4)
- lifestyle
- exposure to ectoparasiticides
- client compliance: difficulty to administer, packaging, smells
- cost