unit 2 parasites part 2

Which lice are chewing and sucking and what does each type eat

sucking- Linognathus setosus (dogs). Chewing- richodectes canis(dogs), Felicola subrostratus(cats)

What are nits

eggs of lice

What common medication used to treat external parasites will kill cats

Permethrin

Why do we treat animals for sarcoptic mange based on clinical signs even with finding no mites on a skin scrape

because it is hard to get a positive skin scrap. And it’s zoonotic.

What are the 3 disease form of demodicosis in dogs

1.      Localized Demodectic mange- < 1 year of age expect German Shepards, found in small areas of skin not very pruritic, not related to an abnormal immune dysfunction. Pups can usually clear it on their own by 8 months of age

2.     Juvenile onset- less than 1 year of age onset. Inherited immunologic defect- T- cell deficiency. It is an inherited problem so don’t breed them. They do require treatment.

3.     Adult-onset demodicosis-> 1 year or older (almost always 8 years or more). Related to some other disease process that affects their immune system, like diabetes, Cushing’s disease, or cancer. Need to treat underlying disease and then treat the demodex.

What is the definition of myiasis and what is the differences in primary and secondary myiasis

Primary- maggots directly invade healthy living tissue. Secondary- Maggots invade already damaged infected or necrotic tissue such as wounds.

What are the lengths of the life cycle phase of the flea

entire life cycle can occur in only 13 days or as long as 11 months. Eggs must hatch within 10 days after being laid. Larvae will only develop into Viable pupae under certain conditions. Once hatched, larvae must become pupae within 14 days. They then transform into pupae in an silk cocoon can remain in their cocoon for up to 30 weeks. Adults will not emerge from the cocoon until a proper environment is present they usually emerge within 3-4 weeks after the egg is laid.

What are the physical characteristics of the flea during the different life cycles (what they look like, where they live, what they do, what they eat)

egg- small white oval found on host or environment. Larva- small worm like found in the environment. Eats organic debris and flea dirt. Pupa- in a cocoon found in the environment develops into an adult fela can remain dormant. Adult small dark wingless. Found on animals eats blood.

What are the stimulants for emergence from the cocoon for fleas?

Carbon Dioxide, increased temp, mechanical pressure ( vibrations).

What diseases are linked to fleas

flea allergy dermatitis ( FAD), Plague, Dipylidium Caninum, cat scratch disease.

What is the causative agent of the plague and what specific type of flea carries it

It is Yersinia pestis, the bacterium that causes it. Xenopsylla cheopis is the carrier. It is acquired through a flea bite

What is the PPP of heartworms

6-7 months

What are aberrant infections in reference to heartworms

eye, peritoneal cavity, spinal cord, extremities, femoral arteries

How long can adult heartworms live in dogs and cats?-

5-7 years 1-2 years in cats

What are the different testing methods for heartworms and what do they look for

Serology looking for microfilaremia. ELISA antigen - testing for female HW uterine protein if neg no HWs if positive, they have it HW. Adult antigen ELISA test- neg they have not been exposed to it; pos, they have been exposed and may or may not have it. Knott’s- looks for microfilaria

Why are there false negatives (negatives that are really positive) and false positives (positives that are really negative)

infection is too recent. Or mostly male worms so no female antigen. Falso pos- testing error or cross-reaction.

What are the very basics of treatment for heartworms and side effects of treatment

administer microfilaricide for 2-3 months. Give treatment of Melarsomine to kill adults. Rest dog for 4-6 weeks. Give second tx of Melarsomine. Run ELIS 4 months after tx to make sure worms are all killed. Check for microfilariae 1 month after 2^nd tx. Downside is dog could die during treatment; it’s expensive, and prevention is safer and cheaper. Killing the adult allows HW to dislodge from the heart, resulting in embolism causing organ failure. Potential for cardiac or respiratory failure.

What bacteria are associated with heartworms, what medication do we use to kill those bacteria, and why do we kill those bacteria before we treat for heartworm?-

Wolbachia spp. By killing it we can speed up the killing of HWs. Tx with doxycycline prior to adulticide because it will often kill or make the adult HW sick

What areosome methods of delivery for heartworm preventative

Ivermectin, heart guard, interceptor, Revolution.

How often do we test for heartworms, how young we start testing for heartworms, and what are some reasons we would test for heartworms?

test annually; earliest to test a puppy is 7 months old

What makes heartworms different in cats vs. Dogs

Cats really have no clinical signs, and they have resistance to the infection. Microfilaremia is rare and they only live up to 2 years in cats.

What are clinical signs of HW in cats?

asthma, open-mouth breathing, coughing, vomiting, anorexia, lethargy. Weight loss, sudden death.

Why do heartworms mimic asthma in cats?-

The worms and immature larvae cause inflammation and damage in the lungs and pulmonary arteries.

How we diagnose HW in cats, and what are the downfalls of each method?

ELISA is neg, no HWs it pos may or may not have them. Adult antigen test if neg may or may not have the, it pos dose have HWs

Why don’t we look for microfilaria in cats to diagnose them

because they either have very few or none ar all In their blood. Many infected cats only have one sex of adult worms.

How do we treat heartworms in cats and why

No treatment its not recommended to kill the adult HWs. Only treat the clinical signs

What gene mutation we worry about in dogs when we discuss heartworm preventatives, what gene and what class of drugs are of concern?

MDR1. Many breeds are Avermectin sensitive. More a concern when giving higher doses of Avermectins than HW prevention