Toxocara canis

Uploaded from authorPOINTLite
Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

By: dr00midoo (29 month(s) ago)

good

By: Borma (42 month(s) ago)

thanks very much

Presentation Transcript

Slide1: 

Toxocara canis By: Nicole Bertram and Cory Polacek

Introduction: 

Introduction Most common worm parasite of dogs 10-40% of adults and 70% of puppies have the worm, but may show no clinical signs There are no specific breed susceptibilities 2-10% of Western Europeans have at some time been infected by this worm’s larvae The larva are the main cause of visceral larva migrans

Background Information: 

Background Information Geographic Distribution: Worldwide Definitive host: Dogs and foxes Intermediate host: Mice and other mammals (not needed) Accidental host: Humans

Morphology of Eggs: 

Morphology of Eggs Eggs are brownish in color and almost spherical They have surficial pits which make them sticky, allowing them to be transported long distances They are unembryonated when laid They can survive 2-4 years in cool, moist conditions

Slide5: 

Alae are long and narrow, prominent in both sexes Males are 4-6 cm in length Females are 6.5 to more than 15 cm in length Morphology of Adult Worm

Adult continued: 

Adult continued Mouth of adult with three lips

Life Cycle: 

Life Cycle

Life Cycle: 

Life Cycle Adult worm found in small intestine of dog Eggs are passed in feces After 5-10 days the egg becomes embryonated and is infective Eggs is ingested and L2 larva hatches in small intestine

Life Cycle: 

Life Cycle If ingested by puppy under 5 weeks of age: L2 larvae enter bloodstream and migrate through the heart and lungs In the lungs in molts into L3 L3 migrates up trachea and is ingested a second time Once in small intestine, it molts into adult

Life Cycle: 

Life Cycle If eggs ingested by dog older than 5 weeks: L2 penetrate intestinal wall and migrate to various tissues The larvae encyst and become dormant Larvae become re-infective during pregnancy Larvae re-enter circulatory system and are carried to the placentas They then penetrate through to the fetal bloodstream and complete a lung migration en route to the small intestine for maturation Thus a puppy can be born with the infection Puppies can also become infected from their mother’s milk, but is not common

Life Cycle: 

Life Cycle If eggs ingested by human or mouse: In these hosts the L2 undergoes developmental arrest They can then wander to various organs and tissues in the body (liver, heart, lung, brain, muscle, eyes)-causing toxocariasis If puppy eats mouse, L2 completes maturation process If dog eats mouse, L2 goes dormant in tissue of dog and may be reactivated during pregnancy

Pathogenesis in Dogs: 

Pathogenesis in Dogs Adults are usually asymptomatic Puppies show clinical signs: Noisy breathing and Cough Nasal discharges Vomiting and Diarrhea Stunted growth rate Distended abdomen (pot belly) Pale mucous membranes Death is rare and is due to obstruction of intestine or ulceration and proliferation of intestinal wall

Pathogenisis in Humans: 

Pathogenisis in Humans Many infections are asymptomatic The two main clinical presentations of Toxocariasis: Visceral larva migrans (VLM) Ocular larva migrans (OLM)

Toxocariasis: 

Toxocariasis VLM Occurs mainly in preschool age children Larvae invade multiple tissues including the liver, heart, lungs, brain and muscles Symptoms include: Fever, anorexia, weight loss, cough, wheezing, rash, hepatosplenomegaly, and hypereosinophilia Severe cardiac, pulmonary, or neurologic involvement can occasionally cause death

Toxocariasis: 

Toxocariasis OLM Occurs in older children and young adults Larvae cause inflammation and retinal scarring Symptoms include red eyes and impaired vision May cause partial permanent vision loss or complete blindness

Diagnosis in Dogs: 

Diagnosis in Dogs All puppies should be assumed to be infected Diagnosis of eggs in feces Eggs are not shed at all times, so false negatives are possible

Diagnosis in Humans: 

Diagnosis in Humans Detection of antibodies by ELISA Western-blot analysis

Treatment in Dogs: 

Treatment in Dogs Puppies-anthelmintics Mebendazole

Treatment in Humans: 

Treatment in Humans VML-antiparasitic drugs (albendazole or mebendazole) usually along with anti-inflammatory medications

Control Measures: 

Control Measures Wash hands after touching soil or dogs Teach children not to eat dirt or to put dirty objects in their mouths Dogs should be wormed starting when they are 3 weeks old Prevent dog feces from contaminating the environment