Bursate Nematodes 1 Flashcards
(26 cards)
Bursate Nematodes
Order Strongylidae
Order Strongylidae
Trichostrongyloidea (Trichostrongyles) - direct life cycles GIT ruminants
Metastrongyloidea (Metastrongyles) - indirect life cycles (mostly) lungworms
Strongyloidea (Stronglyes) - direct life cycles GIT horses
Trichostrongyloidea
Slender, hair-like
Only require one host
Metastraingyloidea
Slightly more “stout”
Indirect lifecycle, require 2 hosts (intermediate host is typically and invertebrate)
Strongyloidea
Well developed buccal capsule
Direct life cycle (only one host)
Typical trichostrongyle lifecycle summary:
Eggs are released in fecal material from infected host hang on the pasture and larvae develop within the egg (L1), larvae emerges from the egg and travels and undergoes a molt (L2), develops into L3 larva through another molt, L3 is the only stage capable of initiating new infection in the new host, L4 and L5 are within the host, L5 matures to become an adult worm
Typical trichostronglye eggs morphology:
You can’t tell much by looking at the egg, only “typical stronglye eggs”
Are typical trichostronglye eggs embryonated when passed in the feces?
No, they are unembryonated
Which lifecycle stages occur in the environment for typical trichostrongyles?
Egg, L1, L2, L3 occur on the pasture
Which lifecycle stage of the trichostronglye is infective?
Only L3 is infective
What appearance does the typical trichostrongyle have?
Retains the L2 cuticle - wrinkled appearance
Trichostronglyes in Domestic Animals:
Genus: Ostertagia
Host: PGE in cattle
Trichostronglyes in Domestic Animals:
Genus: Teladorsagia
Host: PGE sheep
Trichostronglyes in Domestic Animals:
Genus: Haemonchus
Host: Cattle and small ruminants
Trichostronglyes in Domestic Animals:
Genus: Trichostrongylus
Host: Small ruminants (others)
Trichostronglyes in Domestic Animals:
Genus: Cooperia
Host: small ruminates and cattle
Trichostronglyes in Domestic Animals:
Genus: Nematodirus
Host: Small ruminants
Trichostronglyes in Domestic Animals:
Genus: Dictyocaulus
Host: Lungworm, ruminants
Trichostronglyes in Domestic Animals:
Genus: Hyostrongylus
Host: Pigs
Seasonality of Trichostronglye Infection
Eggs and larvae can overwinter in temp climates
Build up of infectivity on pastures over the summer
Greatest disease risk mid-summer and autumn
“There are exceptions”
Increasing the number of hosts in a given grazing space ..
Increases the potential for transmission, thus leads to greater parasite burden
Ostertagia ostertagi
Major parasite control of cattle
Parasitic gastric-enteritis (PGE) - Bovine
Affects mainly calves
Controlled by pasture management, anthelmintics
Bovine PGE - Aetiology
Ostertagia ostertagi
Cooperia spp. and T. Axei contributions
Trichostrongylid nematodes
Large numbers of parasites disrupt GI function
Smaller numbers are of little consequence
O. ostertagi life cycle:
Typical trichostrongylid
L3 exesheaths in rumen, goes to abomasum
PPP=21 days
Prefers 50-77 F or 10-25C
Eggs become “cold conditioned”
L4 burrow into the abomasal glands, emerge into lumen and then mature
