W6 Nematodes Strongyloides and Trichostrongyloidea-I

The relevant genus's of order Rhabditida include

The important orders of phylum Nematoda include

The following image is a parasite of order Rhabditida. Identify the following features of the worm: Corpus, Isthmus, Bulb

Match the following spicules with their correct species of Trichostrongylus species.

These spicules belong to which species of Trichostrongylus and how would you describe their morphology?

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?

Ivermectin and Oxibendazole are appropriate treatments for Strongyloides.

Which of the following techniques can be used to diagnose a strongyloid infection

This is the eggs of [blank_start]S. westeri[blank_end], the strongyloid of the [blank_start]horse[blank_end].

This larva is the larvae [blank_start]S. ransomi[blank_end], it was found in colostrum. These are the strongyloides of the [blank_start]pig[blank_end].

The Trichostrongyles of ruminants are

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.

What are the most important nematode of sheep in south-east Australia?

What are the main pathogenic affects of Trychostrongylus?

Winter Rainfall Zones: - [blank_start]summer too hot and dry[blank_end] - [blank_start]autumn moist, larvae develop[blank_end] - [blank_start]winter moist, grass short[blank_end] - [blank_start]spring “flush” dilutes larvae[blank_end] - rising temperatures shorten survival time Summer Rainfall Zones - [blank_start]winter too cold or dry[blank_end] - [blank_start]larvae develop in spring[blank_end] - [blank_start]maximum numbers in summer[blank_end] Northern Hemisphere (temperate) - [blank_start]winters too cold[blank_end] - [blank_start]development occurs in spring[blank_end] - [blank_start]reaches maximum in autumn[blank_end]