VISCERAL LARVA MIGRANS

typically found in young children.

occurs when a nematode larvae gain entry to extraintestinal viscera of the host.

results in phagocytic attack on the larvae.

caused by: Toxocara canis Toxocara cati

Toxocara canis (dog ascarid)• DH: Dogs and other canids• PH: Rodents• AH: Human

Morphologyo Male

4-6 cm long posterior end is curved ventrally tail is bluntly pointed single tubular testis simple spicules (allows for direct sperm

transfer)

oFemale 6.5-10 cm long has ascarid lips cervical alae are longer than broad

vulva is about 1/3 of the body length from the anterior end

ovaries are very large and extensive

uteri contain up to 27 million eggs

o Eggs 85x75 µ subglobose and pitted superficially

dark brown in color unembryonated when laid very resistant to various weather and chemical conditions.

Life Cycle

Cross-section of Toxocara Larvae in liver tissue

Toxocara cati (cat ascarid)• DH: Cats• PH: Earthworms, Ants and Other soil-

dwelling invertebrates• AH: Human

Morphologyo Male

4-6 cm long has typical slender shape thin head and tail has simple chitinous spicules

o Female 4-12 cm long has ascarid lips pair of broad, lateral cervical alae

large ovaries uteri contain up to 30 million eggs

o Eggs 65x70 µ almost spherical in shape thin shelled and delicately pitted

contain single cell

Life Cycle

SymptomsPhysical symptoms: includes fatigue,

anorexia, weight loss, pneumonia, fever, cough, bronchospasm, abdominal pain, headaches, rashes, and, occasionally seizures

Clinical symptoms: depend on the localization and degree of pathological changes and include non-specific and varied conditions such as eosinophilia, leukocytosis, hepatomegaly, mild gastrointestinal disorders, asthmatic attacks, pneumonic symptoms, urticarial skin changes, central nervous disorders with paralyses

Diagnosis

Clinical Picture – ectopic foci ELISA using secretory excretory antigen Biopsy – liver (demonstrate the characteristic granuloma surrounding a juvenile) Serology – hemagglutination test

– microprecipitation test

Prevention• Periodic deworming of household

dogs and cats• Wash your hands with soap and

water after playing with your pets or other animals, after outdoor activities, and before handling food.

• Clean your pet's living area at least once a week.

• Prevent children from eating dirt.