Both males and females have three prominent lips Each lip has a dentigerous (teeth bearing) ridge Eggs are 75-90 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.
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 http://www.youtube.com/watch?v=-8K9R2M-LfE
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