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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.