Cats and dogs GI nematodes Flashcards
Nematodes of dogs and cats
Family Ascarididae
Ascarids (large roundworms)
Toxocara canis (large roundworms)- dogs
Toxocara cati(large roundworm)- cats
Toxascaris leonina- dogs and cats
Baylisascaris spp. (racoon roundworm) - dogs
Epidemiology/ecology of T.canis
Most common parasite in dogs in canada
Global distribution
Canid definitive hosts (wild too)
Prevalence and intensity highest in young (<6 months)
Eggs survive months to years in enviro
Wide range of vertebrate paratenic hosts
Zoonotic; people are accidental paratenic host
Produce thousands of eggs
Toxocara canis terminology
Larvated egg
Hepatotracheal migration
Somatic migration
Transplacental transmission
Transmammary transmission
Paratenic host
Ways to be infected with T.canis
Direct form the ground
Through milk
Through placenta
Can have an IH
If a dog is breeding female: hypobiotic somatic larvae activate in late pregnancy, migrate across placenta into fetal liver. After birth, complete hepatic-tracheal migration to develop patent infections. Prenatally infected pups can shed eggs at 2-3 weeks old. *Can infect subsequent litters. Transmammary only occurs if female newly infected in late pregnancy
What is the PPP of T.canis
4-5 weeks
Diagnosis of T.canis
Fecal flotation, fecal antigen or fecal PCR
Large adult worms in vomit or stool
Eggs in females
C/s of T.canis
Generally asymptomatic
Pot belly, poor growth, diarrhea
Respiratory signs
Seizures and death (rare)
Epidemiology /ecology or T.cati
Most common parasite in cats in Canada
Global distribution
Prevalence and intensity highest in your young
Wide range of vertebrate paratenic hosts
People MAY be accidental paratenic hosts
Eggs survive months to years in environment cause they are very tough
Common ways to get T.cati
direct from environment
IH with L3 in tissue
Larvae in milk
PPP of T.cati
Kittens 8 weeks
Adult cats 6 weeks
Diagnosis of T.cati
Fecal flotation, fecal antigen, or fecal PCR
Large adult worms in vomit or stool
Eggs in female
How long can T.cati survive in the environemtn
2-4 weeks
Clinical signs in kittens with T.cati
Often asymptomatic; less severe than T.canis
Pot belly, poor growth and coats, diarrhea
Respiratory signs
Seizures and death (rare)
Epidemiology /ecology of toxascaris leonina
Global distribution (including north of 60N)
Canid and felid definitive hosts (wildlife too)
Prevalence and intensity highest in young
Wide range of vertebrate paratenic shots
Not zoonotic
Eggs survive months to years in the environment (*freeze tolerant)
How to get toxascaris leonina
direct or by an paratenic host
How long can toxascaris leonina survive in the environment
1-4 weeks
PPP of toxascaris leonina
8-10 weeks
Toxascaris leonina diagnosis
Fecal flotation, fecal antigen, or fecal PCR
Large adult worms in vomit or stool
Eggs in females
c/s of toxascaris leonina
Often asymptomatic; less severe than T.canis
Raccoon Roundworm (Baylisascaris procyonis) is and common in
Dogs serve as Definitive host, Paratenic host, and mechanical transport hosts
Migrating larva (larva migrans) in a range of vertebrate Paratenic hosts, including dogs and people
Most commonly dogs act as a transport host for the eggs – ingest racoon feces containing Baylisascaris eggs and then contaminate their own environment
Sometimes truly infected with this nematode – adults living in the gut of the dogs and eggs pass in feces
Sometimes dogs become a paratenic host
Control of gin in dogs and cats: CPEP guidelines
Administer anthelmintic treatment at 2,4,6 and 8 weeks of age, followed by monthly preventative to 6 months (can start a bit later for kittens)
Treat nursing females at 2 weeks postpartum (may be patent due to ingestion of stages shed by pup, or reactivation of somatic larvae)
Treat pregnant females off label
Conduct fecal examination 2-4 times during the first year of life and 1-2 times per year in adults
Adults: treat only high risk pets and those with + fecal tests
* macrocyclic lactones, pyrantel, benzimidazoles, emodepside, nitroscanate
What is “high risk” for parasites
High risk animals
Young (<6 months old)
Highly exposed: dog parks, outdoor access, scavengers, hunters, raw food diets
Highly susceptible (immunocompromised, pregnant, nursing)
Animals in high risk households or occupations
Young, old, pregnant, immunocompromised
Service animals
Clinically ill animals
Test high risk animals at least twice a year
Treat high risk animals at least 3-4 times/year
Animal management as a parasite control
Regular disposal of feces (before become infective)
Compliance with pooper-scooper laws
Feed pets cooked, canned or dry food
Prevent predatory and scavenging behaviour
Spay females
Public health measures for parasite prevention
Hand washing
Cover sandboxes
Wear gloves when gardening
Wash or cook vegetables for human consumption
Cook meat to appropriate temp
Nematodes of dogs and cats
Small intestine
Hookworms
Uncinaria stenocephala– DOGS
Ancylostoma caninum – DOGS (Z)
Uncinaria stenocephala (northern hookworm) seen in and control
Most common hookworm in dogs in Canada
eggs/larvae not environmentally resistant
Rarely causes pathology or clinical illness
Regular deworming and pick up feces for control
Not known to be zoonotic
How to get ucinaria stencephala
Direct from enviro of pratenic host with L3
PPP and length in environment of Uncinaria stenocephala (northern hookworm)
PPP 2-3 weeks
Environment 4-8 days
Diagnosis of Uncinaria
Based on history (canadian dog)
Fecal floatation- strongyle type egg
Adult nematode identification
Epidemiology/ecology of A.Caninum
More common in southern USA
Canine definitive hosts
Prevalence and intensity highest in young resistant
Eggs and larvae are not environmentally resistant
Not cold tolerant
Thrive in warm, humid, unsanitary kennel
Zoonotic- people are aberrant definitive hosts
PPP of A. caninum
2-3 weeks
How to get A.caninum
Transmamary- on infection of the dam can infect 3 litters
Paretenic host
direct
though skin
Clinical syndromes in dogs with A. caninum
Per-acute: nursing pups in 2nd week of life, severe anemia in PPP (before eggs are seen in feces), melena, death
Acute: older pups exposed to high infective disease, severe anaemia in PPP (before eggs are seen in feces)
Chronic compensation (partially immune): adult dogs in endemic areas, no or few clinical signs
Secondary decompensation: adult dogs with concomitant health/immunity problems and therefore a variety of symptoms
Pathogenesis of Ancylostoma
Skin (“summer eczema”)
Interdigital spaces, limbs, ventrum
Resp signs- migrating larvae
Blood feeding- pre adults and adults (PPP)
Anemia
In people: cutaneous larval migrans
Diagnosis of ancylostoma
Based on history (S.USA) and clinical signs
Fecal antigen (even in PPP before eggs are shed), fecal PCR
Fecal floatation- strongyle type egg
Adult nematode identification
Control of ancylostoma
Deworm pups and kittens starting at 2 weeks old
Supportive therapy (transfusion); hand raise the puppies
Extra label tx pregnant and lactating female
Spay females
Environmental hygiene and kennel management
Treatment failures increasingly common (some evidence of anthelmintic resistance)
Helminths of cats
Ancylostoma tubaeforme (hookworm)
Ancylostoma tubaeforme is common in and life cycle
Rare in cats in Canada, more common in US
Life cycle similar to Uncinaria- no somatic larvae or transmammary transmission
Most often asymptomatic
Can cause anemia, diarrhea (melena) and weight loss in kittens
Considered potentially zoonotic
SI nematode of dogs
Strongyloides stercoralis (threadworm)
Epidemiology/ecology of S.Stercoralis
Distribution: worldwide, warm and humid (rare in Canada)
People and dogs (cats?) are definitive hosts
Free-living and parasitic cycles
Only females are parasitic
Transmammary transmission (larvae acquired by dam during lactation)
PPP of S.Stercoralis
7-14 days
How to get S.stercoralis
Direct
Through skin
Transmammary
Strongyloides pathogenesis signs
Diarrhea
Resp signs
Chronic bouts of abdominal pain and diarrhoea especially in immunosuppressed dogs/people
Cutaneous larval migrans (people)
Strongyloides stercoralis diagnosis
Larvae detected in Baermann on fresh feces
In older feces, must distinguish from free living larvae and from hatched hookworm larvae
Control of Strongyloides stercoralis
Extra label Macrocyclic Lactones
Environmental hygiene
Large intestine/ceacum worms
Whipworm
Trichuris vulpis (dog)
Head is the skinny end
Trichuris serrata (cat)
Epidemiology/ecology of T.Vulpis (Trichuris vulpis/whipworm)
Worldwide distribution
Canid definitive hosts (cats have other spp)
Direct, simple life cycle
Long prepatent period (PPP)
Eggs are environmentally resistant
Not considered zoonotic
PPP of T.vulpis
2-3 mo
What is the infective stage of Trichurius spp
Eggs with L1
Diagnosis of T.vulpis
Fecal flotation
Fecal antigen (works in PPP), fecal PCR
Adult ID
Pathogenesis of T.vulpis
Often asymptomatic
Adults suck blood (anaemia)
Chronic colitis (sporadic bloody mucoid diarrhea)
Control of T.vulpis
Benzimidazoles, macrocyclic lactones
Tx must be repeated several times
The eggs are very hard to get rid of
Take so long to mature
Environmental hygiene (especially shelters)
