Toxocariasis is an infection caused by worms
commonly found in the intestines of puppies and older dogs
(Toxocara canis), and cats (Toxocara cati). Toxocara worms
produce a large number of eggs in the dog or cat's stomach,
and the eggs then leave their body in their faeces,
contaminating soil and other surfaces.
Humans
become infected by accidentally ingesting (swallowing) worm
eggs, or by eating food that is contaminated with soil
containing the eggs (such as unwashed raw vegetables).
Toxocariasis cannot be spread from person to person. Once the
eggs are in the human body they hatch and the worms begin to
burrow through tissue.
There are
three forms of toxocariasis:
Covert toxocariasis - this form of the
disease is by far the most common. It has mild symptoms or may
have no symptoms at all.
Visceral larva migrans - this form of
the disease develops due to severe or repeated toxocariasis
infection. It can cause swelling of the body's organs or
central nervous system (the brain, spinal cord and the nerves
connected to it).
Ocular larva migrans - this form of the
disease occurs when a Toxocara worm enters an eye. It can
cause reduced vision, and in some cases blindness, in the
affected eye.
The
severity of a toxocariasis infection depends on the number of
worm eggs swallowed and the severity of the reaction to
them.
Children
are most likely to develop toxocariasis, especially children
aged 2-7 years. This is because children are more likely to
come into contact with soil or sand that contains puppy or cat
faeces, and are less likely to follow sensible hand-washing
hygiene.
Glossary
- Tissue
- Body
tissue is made up of groups of cells that perform a specific
job, such as protecting the body against infection,
producing movement or storing fat.
- Brain
- The
brain controls thought, memory and emotion. It sends
messages to the body controlling movement, speech and
senses.
- Stomach
- The
sac-like organ of the digestive system. It helps digest food
by churning it and mixing it with acids to break it down
into smaller pieces.
- Swelling
- Inflammation is the body's response to
infection, irritation or injury, which causes redness,
swelling, pain and sometimes a feeling of heat in the
affected area.
- Faeces
- Stool
(also known as faeces) is the solid waste matter that is
passed from the body as a bowel movement.
