GI Presentations - Ascarids Flashcards
Ascariasis
Toxocara canis
Toxocara cati
Toxascaris leonina
Ascarids - Common name
Roundworms
Toxocara canis - Dog ascarid
Toxocara cati - Cat ascarid
Toxascaris leonina - Dog,Cat ascarid
Ascarids - Hosts and distribution
Canids and felids
Cosmopolitan
Ascarids - Taxonomy
Class: Nematoda
Superfamily: Ascaridoidea
Ascarids - Morphology
Large nematodes in small intestine
Eggs have a thick, pitted shell, contains a single cell
Ascarids - Life cycle
Ingestion of infected larvated eggs or PH with encysted larvae
Burrow through mucosa and enter circulation
Airspaces of alveoli
Ascend to trachea and pharynx, swallowed
Mature in small intestine
Eggs passed in feces
Ascarids - Pathology
Pneumonia
Malnutrtion
Aberrant migration
Ascarids - Clinical signs
Abdominal discomfort Vomiting and diarrhea Pot-bellied Malnourished Death
Ascarids - Diagnosis
Clinical signs
History
Eggs in feces
Idexx fecal antigen
Ascarids - Treatment
Fenbendazole (dogs) Selamectin (cats) Milbemycin oxime Moxidectin topical Pyrantel pamoate Selamectin topical
Ascarids - Treatment of young and pregnant animals
Treat pups and kits starting at 2 weeks and every 2 weeks until broad control begins
Fenbendazole in pregos from day 40 to 14 days postpartum
Ivermectin 10 days pre- and postpartum and 2 weeks postpartum
Ascarids - Reduction of transmammary or transplacental transmission
Selamectin 10 days after breeding and then twice at 30 day intervals
Moxidectin (not FDA approved) topical on day 56
Ascarids - Control
Cooked food
Prevent fecal contamination
Eggs are resistant and can’t treat soil
Control of paratenic hosts
Ascarids - Public health
“Toxocariasis”
Visceral larva migrans
Ocular larva migrans
Toxocara canis - Routes of infection
Ingestion of infective larvated eggs
Ingestion of infective larvae in PH
Transplacental transmission of infective larvae
Transmammary transmission of infective larvae
Toxocara cati - Routes of infection
Ingestion of infected paratenic hosts
Ingestion of infective larvated eggs
Transmammary transmission
Toxascaris leonina - Routs of infection
Ingestion of infective larvated eggs
Ingestion of infected PH
Toxocara canis - Unique morphology
Anterior end showing cervical alae
Toxocara cati - Unique morphology
Arrowhead
Showing cervical alae
Toxocara canis - PPP
Tracheal migration: 30-35 days
Mucosal migration: 21 days
Transplacental: 21 days
Transmammary: 21 days
Toxascaris leonina - PPP
2 - 2.5 months
Toxocara cati - PPP
6 - 8 weeks
Ascarids - Predisposition
Young animals
Raised on dirt or sand
High population density
Ascarids - Egg development
Develop into infective larvated eggs in 2-6 weeks
Baylisascariasis
Baylisascaris procyonis
Baylisascaris procyonis - Hosts and distribution
Raccoons
US, mid-Atlantic, NE and MW states, parts of CA
Baylisascaris procyonis - Eggs
Become infected larvated eggs in 3-4 weeks
Baylisascaris procyonis - Life cycle
Ingestion of infected larvated eggs by young raccoons or ingestion of a larva in an IH
Baylisascaris procyonis - PPP
35 days
Baylisascaris procyonis - Public health
Cerebrospinal nematodiasis
Neutral larva migrans
Continue to grow in human host
Baylisascaris procyonis - Public health
Cerebrospinal nematodiasis Neutral larva migrans Continue to grow in human host Children - CN Adults - OLM Albendazole to treat
Baylisascaris procyonis - Intermediate hosts
Birds and mammals
Eggs hatch and migrate to the liver
Some enter brain and cause CNS disease
Baylisascaris procyonis - Control
Decontaminate environment
Raccoons be quarantined and dewormed
