T. colubriformes, with a barb like tip on the spicules
T. vitrinus, with a barb like tip on the spicules
T. rugatus, with dissimilar and unequal spicules
T. axei, with dissimilar and unequal spicules
The life cycle of Trichostrongylus involves a host stage, a [blank_start]dung[blank_end] stage, and a pasture stage. Dung containing worm eggs is passed from the sheep onto the pasture. At this stage eggs develop through L1 and L2 stages to the L3 stage. The L3 stage is known as the [blank_start]infective[blank_end] stage. Generally development to the infective stage is markedly reduced at temperatures below [blank_start]10˚[blank_end] and above [blank_start]35˚[blank_end]. During the pasture phase the L3 larvae migrate into [blank_start]moisture[blank_end] where they wriggle, some onto pasture, where they will then be consumed by the host. During the pasture phase the [blank_start]cuticle[blank_end] of L2 is retained by [blank_start]L3[blank_end] and acts to protect it from harsh conditions in the environment. After the L3 larvae is consumed it is [blank_start]exsheathed[blank_end] in the [blank_start]rumen[blank_end]. Infective larvae become adult that live for many months within the sheep's gut to reproduce and lay eggs. The minimum time from L3 to egg laying is [blank_start]18[blank_end] days.
Name the strongyloid species that affect the mammalian hosts below. For example S. stercoalis is a strongyloid of dogs, cats and humans.
Ruminants = [blank_start]S. papillosus[blank_end]
Pigs = [blank_start]S. ransomi[blank_end]
Horses = [blank_start]S. westeri[blank_end]
Cat = [blank_start]S. cati[blank_end]
[blank_start]Primates[blank_end] = S. fuelleborni
The parasitic strongyloides are all found in the stomach, with the exception of the kangaroo species which can be found in the small intestines.
Which of the following statements is false regarding the lifecycle of S. papillosus?
Only female worms have been found parasitising the host
There is a homogonic lifecycle and a heterogonic lifecycle
The heterogonic lifecycle is free living and has a rhabditiform oesophagus
At temperatures above 34˚C the parasitic lifecycle is triggered.
The L1 and L2 larvae of the homogonic lifecycle have the oesophageal morphology of a filariform
Ivermectin and Oxibendazole are appropriate treatments for Strongyloides.
Which of the following techniques can be used to diagnose a strongyloid infection
Eggs - faecal flotation
Larvae - Baermann technique
In vitro culture
Serodiagnosis - ELISA
A streak culture on HB agar
This is the eggs of [blank_start]S. westeri[blank_end], the strongyloid of the [blank_start]horse[blank_end].
Trichostrongyles of ruminants that are found in the [blank_start]small intestine[blank_end] include;
"Black scour worm" = [blank_start]Trichostrongylus[blank_end]
"Wire worm" = [blank_start]Cooperia[blank_end]
"Thin-necked intestinal worm" = [blank_start]Nematodirus[blank_end]
Trichostrongylus species can cause the signs seen in this image.