Blood Helminths II

The parasite is Acanthocheilonema reconditum, where do the adults live in the host, what do you find, how do you find them (what tool), and why does it matter

• under the skin of the dogs

• Microfilariae in blood

• Knott's test

• A harmless look-alike of heartworm

The parasite is Dirofilaria repens, where do the adults live in the host, what do you find, how do you find them (what tool), and why does it matter

• Under the skin of dogs (Europe, Asia, Africa)

• Microfilariae in blood

• Knott's test or PCR

• Imported dogs; infects people

The parasite is Heterobilharzia americana, where do the adults live in the host, what do you find, how do you find them (what tool), and why does it matter

• Mesenteric veins of raccoons and dogs

• Eggs in feces

• Fecal PCR or saline sedimentation

• Swimming dogs; spreading

  west

Where do the adults of Acanthocheilonema reconditum live in and what do they do

The adults live under the skin of dogs and release a few microfilariae into the blood.

What spreads Acanthocheilonema reconditum

Fleas spread it: the flea swallows the microfilariae, and they reach the L3 in 7–14 days.

When we test for Acanthocheilonema reconditum do we see it in the anitgen testing and is harmful on the dog

It is harmless to the dog, and the heartworm antigen test is negative.

Is there a treatment for Acanthocheilonema reconditum

No treatment is needed; flea control stops it. It is not a risk to people.

Why should we identify the microfilarieae before any adulticide why?

Call it heartworm by mistake, and you give arsenic to a dog that does not need it.

Where does Dirofilaria repens lives in what host, how is it spread, and where do you find it (what country is in)

• It lives under the skin of dogs,

• mosquitoes spread it,

• it is found in Europe, Asia and Africa.

Is Dirofilaria repens estabilished in the US

It is not established in the USA: a US survey of 2,334 dogs and cats found none. It has been found in a dog imported from Slovakia.

Do some dogs show signs/symptoms when Dirofilaria repens is in the body

Most dogs show no signs; some have skin nodules.

How do we find Dirofilaria repens

Find it with a Knott's test or PCR. Heartworm antigen tests miss it.

Is there a medication for Dirofilaria repens

Monthly preventives protect against it; moxidectin works best.

The parasite is D. immitis describe the length, head, tail, vector, and why is it important

• Length: 295–325 μm

• Head: Tapered

• Tail: Straight

• Vector: Mosquito

• Does it matter? Pathogenic

The parasite is A. reconditum describe the length, head, tail, vector, and why is it important

• Length: 250–288 μm

• Head: Blunt, with a hook

• Tail: Button-hook (about 1 in 3)

• Vector: Flea

• Does it matter?: Harmless

The parasite is D. repens describe the length, head, tail, vector, and why is it important

• Length: 250–288 μm

• Head: Blunt, with a hook

• Tail: Button-hook (about 1 in 3)

• Vector: Flea

• Does it matter?: Harmless

The parasite is D. repens describe the length, head, tail, vector, and why is it important

• Length: 300–370 μm

• Head: Round

• Tail: Long, sharp, often curved

• Vector: Mosquito

• Does it matter?: Nodules; zoonotic

Describe the sexes of H. americana? Is H. americana a fluke?

• Heterobilharzia americana is a schistosome (a blood fluke).

• The sexes are separate, and the slender female lies in a groove of the male.

Where does H. americana live in the host

The adults live in blood vessels, the mesenteric veins, which is why it is a blood helminth. Its eggs pass in the feces.

What animal is the reservoir for H. americana

Raccoons are the reservoir; dogs and horses are also infected.

H. americana is an endemic for what part of the world

It is endemic on the Gulf Coast and in the Southeast: Texas, Louisiana, Florida, Georgia and the Carolinas.

If a dog is affected by H. americana what should we ask the owners

does the dog swim or wade in fresh water, and where has it been?

H. americana Male and female pairs live in the

mesenteric veins; their eggs pass through the gut wall into the feces.

In fresh water the H. americana eggs do what

eggs hatch at once, and the miracidium enters a lymnaeid snail.

Cercariae swim out of the what

snail and penetrate the skin of a dog that wades or swims.

The young flukes travel through the ( in H. americana

through the lungs to the liver, then to the mesenteric veins. Eggs appear in the feces after about 10 weeks.

What does the life cycle of H. americana tell us

infection needs water and snails, so swimming dogs are at risk. The eggs hatch in water, so feces are sedimented in saline. Raccoons keep the parasite going.

Describe the eggs of H. americana

The eggs, not the worms, do the damage: trapped eggs form granulomas in the gut wall and the liver.

Do dogs shows signs and symptoms for H. americana

• Many dogs show no signs.

If the dog has H. americana and the sign is Diarrhea and vomiting what does the blood work look like

High globulins

If the dog has H. americana and the sign is Weight loss, poor appetite what does the blood work look like

Eosinophilia appears

If the dog has H. americana and the sign is Severe cases: liver and

gut failure what does the blood work look like

Hypercalcemia: the classic finding, but uncommon

About 1 in 6 treated dogs live or die from H. americana

died of the disease in a 2021 series of 60 dogs.

How do you diagnosis H. americana —

• Fecal PCR is the most sensitive test.

• Saline sedimentation recovers the eggs. Use saline, not water: in water the eggs hatch and are lost.

• A routine flotation misses the eggs.

• Ultrasound shows pinpoint bright foci (mineralized granulomas) in the gut, liver and lymph nodes.

How do you control H. americana

keep dogs out of water known to be infested. Raccoons keep the

infection going.