Chapter 6 - Parasitic Flashcards
Which receptor does Fiprionil antagonise?
GABA
Pyrethrins are rapidly inactivated by what?
Moisture
Air
Light
New pyrethroids, e.g. permethrin, are more stable in UV light
The efficacy of 0.06-0.4% pyrethrin is improved when used with which other agent?
0.1-2% piperonyl butoxide
What is the plasma resident time of ivermectin/moxidectin in horses? 1-2 days 5-7 days 12-14 days 18-20 days
18-20 days
How long is the life cycle of Psoroptes mites?
~10 days
With psoroptic mange in horses, which body sites does dermatitis tend to be focused around?
Ears (P. cuniculi)
Mane
Tail
(Can present as mane and tail seborrhea)
Body mange (P. equi)
Where does pruritus typically start with sarcoptic mange in horses?
Head, ears and neck then spreads caudally
Can occur on the distal limbs if acquired from a fox during a hunt
Chorioptes mites can survive off host for how long?
Up to 70 days
What are the clinical signs of demodicosis in horses?
Asymptomatic hypotrichosis, alopecia, scaling, and occasionally crusting over the face, neck, shoulders and forelimbs.
Is Werneckiella equi a biting or sucking louse?
Biting/chewing
Aedes, Anopheles and Culex are which type of fly?
Mosquitoes
Which mosquitoes require the presence of water for their eggs to hatch?
Aedes
They all lay their eggs in water/moist vegetable material but only Aedes require water for hatching
What are the two most common distributions on the horse for Culicoides bites?
Topline and tail
Ventrum
Which biting fly needs cow manure for eggs to develop?
Horn fly (Haematobia spp.)
Need proximity to cattle!
Which fly can carry Habromema eggs or larvae?
Musca domestica
Which biting fly tends to cluster in the perineal and inguinal regions?
Louse flies (keds) Hippobosca spp.
Which flies are associated with ventral midline dermatitis?
Culicoides spp.
Haematobia spp.
With warbles, at which body site do nodules form in horses?
Withers
Small, 1mm, yellowish tissue granules can be seen with which parasitic disease?
Habronemiasis
What is a characteristic histopathological feature of cutaneous habronemiasis?
Multifocal areas of discrete coagulation necrosis which consume all cutaneous structures in the area.
Which test can you use to diagnose habronemiasis if larvea are not visible on histopathology?
PCR
Which treatment can rapidly resolve habronemiasis lesions?
Steroids (systemic or intralesional); suggests a hypersensitivity?
Treatment also includes systemic ivermectin and surgical debulking
Match the Onchocerca spp. with their intermediate hosts and body sites:
O. gutturosa
O. reticulata
O. cervicalis
- Funicular portion of the ligamentum nuchae (neck) - Culicoides spp. and mosquitoes
- Lamellar part of the ligamentum nuchae (neck) - Simulium spp.
- Connective tissue of the flexor tendons and suspensory ligament of the fetlock - Culicoides spp.
O. gutturosa - Lamellar part of the ligamentum nuchae - Simulium spp.
O reticulata - Connective tissue of the flexor tendons and suspensory ligament of the fetlock - Culicoides spp.
O. cervicalis - Funicular portion of the ligamentum nuchae - Culicoides spp. and mosquitoes
What treatments can be used for sarcoptic mange in horses?
2% lime sulfur
Ivermectin or moxidectin (multiple treatments at 12-14 day intervals)