Parasitology Exam 1 (Ch. 3-4)

T or F: Nematodes are multicellular organisms unlike protozoans

True

What are some morphological features of nematodes?

• They are unsegmented and elongated

• Round on both ends

• Bilaterally symmetrical

The largest nematode known to parasitize domesticated aminals in the ____ the “giant kidney worm” of dogs

Dioctophyma renale

Nematodes are covered by a thin ____. This covers the exterior body service and extends into all its body openings. 

cuticle

In nematodes, the ____ is right beneath the cuticle and it is what produces the cuticle

hypodermis

In nematodes the ____ is beneath the hypodermis and it is what allows the nematode to move

somatic muscular layer

What are the most important organ systems for the nematodes?

digestive and reproductive 

T or F: Female nematodes have a rectum and males have a cloaca

True

Nematodes are ____, meaning that the species produces both female and male individuals

dioecious

Ascarid/roundworm type (Toxocara canis)

Spirurid type (Physaloptera spp.)

Trichostrongyle/hookworm type (Ancylostoma caninum)

____ - the pre larval stage

Microfilarae

Dirofilaria immitis larvae

____ - have a kinked tail larvae

lungworm larvae

Aelurostrongylus abstrusus larvae

____ - have a long-tailed larvae

Dracunculoid larvae

Dracunculus insignis larvae

____ - the eggs produced by these nematodes contain a single-cell stage or a morula stage within the eggshell

Oviparous

____ - the eggs produced by the female nematodes contain a first-stage larva within the eggshell 

Ovoviviparous

____ - female nematodes retain their eggs within the uterus and incubate them, then give birth to live larvae

Larviparous

Life Cycle of Nematode

The third stage larva is known as the ____ because it is infective for the definitive host. 

infective third-stage larva 

Once the infective third-stage larva has been reached, it must return to the definitive host to survive by one of 2 ways:

1. Direct penetration

2. Intervention of the intermediate host

____ - this is where there is no intermediate host in the life cycle

direct life cycle

What is an example of the direct life cycle?

Canine hookworms develop to the infective 3rd stage in the external environment. They penetrate dog’s skin and migrate to the small intestines 

____ - this is where there is an intermediate host in the life cycle

indirect life cycle

What is an example of the indirect life cycle?

A female mosquito ingests the microfilariae along with her blood meal from the infected animal. The microfilariae develop into the infective 3rd stage larva within the mouthparts of the mosquitoes. When the mosquito feeds again, the infective 3rd stage migrates into the uninfected animal.

What are the hosts for the Physaloptera species?

canines and felines 

Where is the Physaloptera species located in adult animals?

the lumen of the stomach or the small intestine

What is the transmission route for Physaloptera species?

ingestion of eggs

What is the common name for the Physaloptera species?

Stomach worm

What does the Physaloptera species feed on?

blood

What are the clinical signs of an animal infected with Physaloptera?

• vomiting

• anorexia

• dark tarry stools

How do you diagnose Physaloptera?

fecal flotation and vomitus

Who is the host of Toxocara canis?

canines

Who is the host of Toxocara cati?

felines

Who is the host for Toxascaris leonina?

canines and felines

What is the route of transmission for Toxocara canis/cati and Toxascaris leonina?

Ingestion of egg with infective larva

What is the common name for Toxocara canis and Toxocara cati?

Canine and Feline Roundworms

Toxocara canis 

Toxocara cati

Toxascaris leonina 

When Toxocara canis/cati are passed through the feces, the adult worms usually appear ___

tightly coiled

What are the clinical signs of Toxocara canis/cati?

• vomiting

• diarrhea

• constipation

• pot-bellied appearance

How do we diagnose Toxocara canis/cati?

fecal flotation

What is the treatment for Toxocara canis/cati?

• Vermifuge (Piperazine or Pyrantel)

• Vermicide (Thiabendazole or Mebendazole) 

How does vermifuge work?

It paralyzes the parasites

How does vermicide work?

It kills the parasites

T or F: Toxocara canis larvae can cross the placental barrier and infect the host’s offspring but Toxocara cati can not

True

Toxocara spp. can also infect humans and it can cause what?

visceral larval migrans

Life Cycle of the Roundworm

Who is the main host for Baylisascaris procyonis?

Raccoon 

What is the location of Baylisascaris procyonis within an animal?

small intestines

What is the route of transmission for Baylisascaris procyonis?

Ingestion of eggs

What is the common name for Baylisascaris procyonis?

Raccoon roundworm 

How is Baylisascaris procyonis diagnosed?

fecal flotation

T or F: Baylisascaris procyonis is not a zoonotic disease?

False

Baylisascaris procyonis larvae migrate to the central nervous system and they produce a condition known as ____

Neurological larval migrans 

Baylisascaris procyonis 

Who is the host for Ancylostoma caninum?

Canine

Who is the host for Ancylostoma tubaeforme?

Feline

Who is the host for Ancylostoma braziliense?

canine and feline

Who is the host for Uncinaria stenocephala?

canine

What is the location for Ancylostoma caninum in adult animals?

the small intestine

What is the route of transmission for Ancylostoma caninum?

• ingestion of eggs

• through the skin 

• across the placenta

• through the mammary milk

What is the common name for Ancylostoma caninum?

Hookworm

What is the scientific name for Hookworm?

Ancylostoma caninum

Ancylostoma caninum (Hookworms)

What does the hookworm feed on?

blood

____ feed on blood and secrete an anticoagulant from its mouth. Because of this feeding activity and secondary hemorrhage, they can cause significant anemia

hookworms

What are the clinical signs of Ancylostoma caninum?

• black tarry stool

• severe anemia in young puppies and kittens

How is Ancylostoma caninum diagnosed?

fecal float 

Ancylostoma caninum (Hookworms)

What are the two treatments for Ancylostoma caninum?

• Vermicide: this is used when parasite eggs are found on fecal flotation of by other techniques

• Prevention: this is accomplished by using once-a-month heartworm preventatives

What are some examples of vermicides used to treat Ancylostoma caninum?

• Mebendazole

• Fenbendazole

• Pyrantel pamoate

What are some examples of prevention used for Ancylostoma caninum?

• Heartgard Plus

• Ivermectin 

• Pyrantel 

Is Ancylostoma caninum a zooinotic disease?

yes

Ancylostoma caninum can enter the skin of humans, this is known as _____

cutanious larva migrans

What are the two types of Strongyloides species in cats and dogs?

• stercoralis

• tumiefaciens

Who is the host for Strongyloides spp?

• dogs

• cats

• humans

What is the route of transmission for Strongyloides spp?

Through the skin and through the milk

What is the common name for Strongyloides spp?

Intestinal threadworm

Strongyloides species

T or F: With the Strongyloides species, parasitic males do not exist, the females are capable of producing viable ova without fertilization from a male worm.

True

When a female is capable of producing viable ova without fertilization from a male worm, this is known as what?

parthenogenesis 

In the Strongyloides species, in fresh feces, you may see ____ stage larvae

1st

In the Strongyloides species, the larvae go through a free-living stage in the environment before they become the ____ and can penetrate the skin of their host

infective L3

What are the clinical signs of Strongyloides species?

moderate to severe diarrhea in young puppies 

Is the Strongyloides species a zooinotic disease?

yes

When humans are infected with the Strongyloides parasite, it is called ____

strongyloidiasis

Who is the host of Trichuris vulpis?

canines

Who is the host for Trichuris campanula?

Felines

Who is the host for Trichuris serrata?

Felines

What is the location of Trichuris vulpis in adult animals?

cecum and colon

What is the route of transmission for Trichuris vulpis?

ingestion of eggs

What is the common name for Trichuris vulpis?

Whipworm 

What is the scientific name for whipworm?

Trichuris vulpis

T or F: Trichuris vulpis is a common parasite of cats, but canine whipworms are rare in North America

False, it is a common parasite of dogs, but feline whipworms are rare in North America

The whipworm eggs are passed out in the feces of the host every ___ day. 

3rd