Parasitology nematodes pt 1...? round worms?

What are some basic characteristics of Nematodes?

Multicellular organisms, with cylindrical bodies. They have one tube straight from the mouth to the anus. They have reproductive organs that wrap and coil around the digestive crew. They have a nervous system but no respiratory system.
They have a Cuticle – a body wall composed of an external, acellular, protective
layer. - Hypodermis – cellular layer beneath the cuticle. They have a layer of longitudinal somatic muscles that function in locomotion

What are Nematodes?

Roundworms. The biggest group of worms we look at it.

What is the life cycle of the Nematode?

Developmental stages: Egg, five larval stages, sexually mature adult.

What are the 5 larval stages?

L1-L5.

What larval stage is the infective stage?

Larval stage 3, enters definitive host.

What is a direct life cycle?

Direct - No intermediate host is needed for development to the infective stage.

What as an indirect life cycle?

An intermediate host is needed for development to infective stage.

Taxonomic super families of Nematodes in vet med..?

 Ascaroidea (round worms)
 Strongyloidea (hook worms)
 Trichostrongyloidea - Ruminants
 Rhabditoidea (intestinal threadworms)
 Metastrongyloidea (lung worms)
 Trichuroidea (Whip worms)
 Oxyuroidea (pinworms)
 Spiruroidea (stomach /esophageal) worms
 Dracunculoidea – very uncommon
 Dioctophymoidea (kidney worms)
 Filaroidea (filarial – heartworm, ect.)

Some other parasites that fall into nematodes..? Misc worms that don’t fit into hooks, rounds, or whips?

 Unicinaria stenocephala-hookworm (uncommon)
 Dioctophyma renale-kidney worm
 Physaloptera spp.- stomach worm
 Dirofilaria immitis – heartworm
 Aelurostrongylus abstrusus- feline lung worm
 Pearsonema (Capillaria) plica – urinary bladder worm (dogs)
 Pearsonema (Capillaria) feliscati – urinary bladder worm (cats)
 Eucoleus (Capillaria) aerophilus – trachea and lungs of cats and
dogs
 Acanthocheilonema (Dipetalonema) reconditum- non pathogenic
worm of the subcutaneous tissue of dogs
 Spirocera lupi – esophageal worm

Nematodes vs Ascarids.

Nematodes is a phylum.?

Ascarids are a family.

Nematodes: Worms that are literally round. Include hooks, pin worms, whip worms, etc.

Ascarids are talking specifically to the Ascaroidea family. Also called “roundworms”.

What are the most common nematodes seen in cats in dogs?

Toxocara canis (round ascarid), toxocara cati, Ancylostoma caninum (hook worm), and Trichuris
vulpis (whip worm) (dogs only). These are all intestinal worms.

What is the round worm in the raccoon, but seen in many species and is zoonotic? And what can it do?

Baylisascaris procyonis. Can migrate to the CNS – producing neurologic larval migrans.

What are the ascarids of dogs and cats?

Toxocara canis, T cati, and T. leonina.

Where are ascarids found?

In the intestinal tract of dogs and cats.

What are the physical characteristics of a typical ascarid in dogs and cats?

3 to 18 centimeters in length. Tend to be large, white or cream colored nematodes-
Males are 3.5- 5cm long, and females are 10-15 cm long.

What is the prepatent period for T. Canis and T. leonina? ***

Prepatent period for T. canis – 21 to 35 days; T. leonina is
74 days. KNOW THE DIFFERENCE

What is the life cycle of an Ascarids?

L1 develops in the eggs, L2 stage is formed, and this is the infective stage for this parasite.? Once eggs are ingested, the larvae hatch in the small intestine, penetrate the mucosa, migrate through the liver, pass through the heart, and go into the lungs. The larvae are then coughed up, swallowed, and mature to the adult stage, all within 4 to 6 weeks.

What else will larvae sometimes do that leads to worms being transferred from mom to babies.

These larvae may also leave normal circulation and be stored in the organs until a dog becomes pregnant. Some of these larvae will migrate to the mammary glands, and thus the larvae are passed on to the nursing puppies and kittens. Transmammary infections are more common in cats than in dogs.
T. canis has intrauterine (can infect in the uterus) but T. cati does not!

T. canis and T. cati, can they go intrauterine?

T. canis has intrauterine (can infect in the uterus) but T. cati does not!

What are the 3 different ways a pet can get ascarids?

Intrauterine, ingestion, and trans mammary?

What are round worm (Ascarid) eggs like?

Eggs are large, round-oval, dark colored with a thick, rough shell. Toxascaris leonina eggs are lighter in color, and have a smooth, thick shell to it. Typically 75-90mm

What is something serious that can affect humans from round worms?

Round worms are also responsible for visceral larval migrans – clinical condition of 3rd stage larvae migrating through an abnormal host such as children. So they are zoonotic!

What is the infective stage of round worms (Toxocara)?

L2

What is the equine round worm?

Parascaris equorum

What is the cattle round worm?

Toxocara vitulorum

Advancement/life cycle of the parascaris equorum/horse round worm.

When the infective egg is swallowed by a foal, the larvae hatch, burrows into the wall of the small intestine, and then is carried to the liver by the portal vein. Then it is carried to the vena cava, heart, pulmonary artery to the lungs, and eventually returns back to the stomach by way of the lumen of the esophagus.

What are some effects/damages from parascaris equorum/horse round worm.

The damage caused to the liver and lungs eventually heals, but can cause a yearling to be smaller than normal due to complications that might normally allow growth spurts in the young horse.

Swine round worms?

Ascaris suum and Ascaris lumbricoides.

Who does Ascaris lumbricoides affect?

Swine and human

How do round worms infect the host/life cycle in animal?

ingested, then they hatch in the small intestine, penetrate the mucosa and migrate through the liver, pass through the heart and then go unto the lungs. The larvae then are coughed up, swallowed, and then mature into the adult stage.