Order: Ascaridida › Family: Toxocarida › Genus: Toxocara › Species: T. canis  Geography: Worldwide

 Both males and females have three prominent lips  Each lip has a dentigerous (teeth bearing) ridge  Eggs are micrometers  embryonated when laid  Have pits  Very resistant to various weather and chemical conditions  Males: › 4-6 cm long  Females: › 6.5 cm long › can be as long as 15 cm › The vulva is about one-third the body length › The uteri can contain up to 27 million eggs at a time.

 Toxocara egg  Larvated eggs

 Larvae

 Adults

 Humans become infected by ingesting infective eggs, often due to close contact with puppies or from egg infected with soil  Transuterine transmission › puppy can get from mother during pregnancy or from mother’s milk.

 Definitive host: Dog or other canid  Paratenic hosts: mice, rabbits, and monkeys  Accidental host: Humans

 Toxocara cati › Very similar to Toxocara canis › One of the most common feline helminths

 Toxocara canis causes toxocariasis: a zoonotic infection caused by the parasitic roundworms found in the intestine of dogs.

1) Ocular larva migrans (OLM):  Toxocara infections can cause an eye disease which can cause blindness.  OLM occurs when a microscopic worm enters the eye  Each year more than 700 people infected with Toxocara experience permanent partial loss of vision.  OLM occurs when larvae enter the eye. This results in a loss of vision or severe ocular inflammation

2) Visceral larva migrans (VLM):  Repeated Toxocara infections can cause a disease that causes swelling of the body’s organs or central nervous system.  When the larval parasite migrates through the human body it is known as larval migrans.  In the UK alone there are over 300 cases of toxocariasis diagnosed each year.

 Symptoms : › VLM: include abdominal pain, fever, coughing, wheezing and asthma › OLM: include ophthalmologic lesions › Often found in children aged between 2 & 7 › Can also be asymptomatic

 Is usually made by serology or the finding of larvae in biopsy or autopsy specimens.  ELISA – › positive in 78% of those with visceral larva migrans › positive in 45% of those with ocular toxocariasi

 Cross-section of Toxocara Larvae in liver tissue

 Prednisone  Albendazole or Mebendazole

 Don’t allow dogs to lick your face  Wash hands after playing with pets  Avoid infected areas  De-worm dogs

 Small children are susceptible  Prelevant because every puppy is assumed to have this helminth

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