Nematodes

Question 1

Nine things to know

Answer 1

Scientific/common name
Hosts
Diagnosis
Identification
Site of infestation
Life cycle- with PPP  variations
Treatment and prevention
Clinical Sings, pathogenesis, lesions
Zoonotic

Question 2

Why do veterinarians need to know parasites?

Answer 2

To:
Prevent disease
Minimize impact on production
Maintain food security
Prevent zoonosis
Answer the 6 common questions asked by clients

Question 3

6 questions asked by clients

Answer 3

1. What is it?
2. How can you tell they have it?
3. Where did it come from? How did my animal become infected?
4. What harm does it cause?
5. How can it be gotten rid of?
6. Will it infect people?

Question 4

Definitive Host

Answer 4

Host in which the parasite can fully mature and begin reproducing
Direct Life Cycle

Question 5

Final Host

Answer 5

Host in which the parasite can fully mature and begin reproducing
Indirect Life Cycle

Question 6

Intermediate Host

Answer 6

Host in which a parasite matures to a specific lifestage

Parasite will never mature here, no eggs in feces

Question 7

Aberrent host

Answer 7

“accidental host” able to infect animal that is not direct host
Different signs than FH- usually more severe damage

Question 8

Paratenic host

Answer 8

host that is able to harbor the parasite, however no maturation or reproduction is occurring; parasite just hangs out here

Question 9

Prepatent period

Answer 9

period of time between initial infection of parasite to full/sexual maturity

Question 10

Periparturient rise

Answer 10

Increase in parasite reproduction around parturition, due to suppressed immune system of the mother; parasite takes advantage of conditions

Question 11

Predilection site

Answer 11

location the parasite prefers to occupy

Question 12

Aberrant site

Answer 12

abnormal location for parasite to occupy

Question 13

Nematodes General

Answer 13

Roundworms: long, white, round, elongated, typically unsegmented
Complete alimentary canal
Separate sexes; male have bursa in some species
Life cycle: Egg-L1-L2-L3-L4-L5-adult
most are direct life cycle some have indirect

Question 14

SSH

Answer 14

Site of infection- organ, GI tract, blood, sputum, feces, muscle
Size- microscopic, macroscopic, big, average, small, tiny
Morphological characteristics
Clinical signs

Question 15

nematode identification

Answer 15

Necropsy: adults, larvae (L4, immature adult-L5, and

Question 16

Morphological characteristics eggs and L1

Answer 16

Size
shape- round, oval
Shell- thick, thin, smooth, rough
with or without larva
bipolar plugs
operculum 
L1-tails

Question 17

Direct life cycle

Answer 17

Eggs passed in faeces
L1 develops, eggs embryonate in 5 days +
First stages larvae in feces
second stage in feces
Third stage (infective) larvae migrate onto grass in approximately 3 weeks
ingested L3 develop through l4 and l5 to adult egg laying worms

One host to complete the life cycle
Definitive host

Question 18

Indirect life cycle

Answer 18

Larvae mature into adults in heart
Female adult worms release microfilariae in blood
Mosquito ingests microfilariae with blood meal
Microfilariae develop in mosquito to infective larvae
Mosquito bites dog or cat and transmits infective larvae

Two or more hosts to complete a life cycle
Final host (sexual reproduction) and intermediate hosts (immature stage)

Question 19

Order Strongylida

Answer 19

Ancylostomatoidea, strongyloidea, and trichostrongyloidea
Life cycle: direct, infection by L3
Males have bursa
Arrested development ( usually L3 or L4- parasite specific)- stop development due to immune system of host or changing environmental conditions
Eggs: thin shelled, oval, average size, can float
Metastrongyloidea: exception

Question 20

Flotation

Answer 20

using the weight of eggs and the weight of a solution to force eggs to the top of the solution

Question 21

Simple flotation

Answer 21

Eggs float over time

Question 22

Centrifugation

Answer 22

G-force used to float eggs faster and in media that is thick

Question 23

McMaster

Answer 23

Simple float method designed to count the eggs per gram of feces

Question 24

Ancylostomatoidea

Answer 24

Bent dorsally; fishing hook
Adults: small; 1-2cm; buccal capsule modifications (teeth, cutting plates)
Egg: oval, thin shelled, average size
Adults: small intestine
Larvae: some limited migration in lungs
AnemiaL feed on blood; ulcers
Young animals most sever signs
Limited immunity
Attach to intestinal villi with large mouth (buccal) cavity
Hemorrhaging
Anemia

Question 25

Ancylostoma Caninum

Answer 25

Hookworm Final host: dogs and foxes Paratenic host: things that dogs hunt Zoonotic Adult: small; characteristic hook appearance Eggs: oval, thin shelled; 60x40 um (medium sized) Life cycle: direct Southern Hookworm Throughout US

Question 26

Ancylostoma Caninum Modes of infection:

Answer 26

Modes of infection: percutaneous; penetration of oral mucosa; per os; paratenic hosts; transplacental and transmammary (IMPORTANT) Arrested development L3 Lung migration

Question 27

Ancylostoma Caninum SItes of infection

Answer 27

Adults: small intestine Larvae: some migrate lungs

Question 28

Ancylostoma Caninum Pathogenesis and lesion

Answer 28

Peracute, acute or chronic hemorrhagic anemia Pups infected by transmammary route challenged; 1st week okay, 2nd week deteriorate with less than 100 worms Moist eczema with percutaneous infection

Question 29

Ancylostoma Caninum Clinical signs

Answer 29

Peracute: immature worms causing hemorrhaging Acute infections: anemis and lassitude; respiratory disease, pneumonia; diarrhea (blood and mucus) Chronic infections: weight loss, poor hair coat etc

Question 30

Ancylostoma Caninum Diagnosis

Answer 30

Clinical signs History with hematological and fecal examinations A few hookworm eggs confirms infection only, not hookworm disease L4/early mature also feed on blood Typical egg 60x40 um fecal float in less than 14 day old puppies only clinical signs

Question 31

Ancylostoma Caninum Treatment and prevention

Answer 31

Anthelmintics -adult and larvae -species specific Larval leakage Young pups: iron; blood transfusion and treat asap Nutrition Treat pups and adults Treat pregnant dogs at least once during pregancy -frequency and timing dependent on the drug used -treatment through day 14 of lactation Capcvet: treat at 2, 4, 6, 8 weeks of age Other: treat nursing litters twice at 1-2 weeks and again 2 weeks later

Question 32

Ancylostoma tubaeforme

Answer 32

``` Similar to a. caninum except: Host is cats Life cycle -per os, percutaneous, paratenic hosts, NO TM or TP Zoonotic Throughout US ```

Question 33

Ancylostoma braziliense

Answer 33

``` Similar to a caninum except: Host dogs and cats Life cycle -per os, percutaneous, paratenic hosts Pathogenesis: less of a bloodsucker so less pathogenic MOST ZOONOTIC: cutaneous larva migrans Gulf coats area ```

Question 34

Uncinaria stenocephala

Answer 34

``` Northern us- Northern hookworm Hookworm Hosts -final= dogs, cats, foxes -paratenic hosts Life cycle -per os usual route -percutaneous uncommon -no TP, no TM ``` Eggs: oval, thin shelled, 80x40 um (medium) Uncinaria and ancylostoma eggs difficult to distinguish Less zoonotic less voracious bloodsucker Interdigital dermatitis in animals previously infected

Question 35

Brunostomum

Answer 35

``` Ruminants Percutaneous, oral, no TP, TM Bottle jaw diarrhea Cool climates ```