Risk of Toxocariasis Transmission from Dogs to Children
Children are at significant risk of Toxocara roundworm infection from dogs, particularly through accidental ingestion of infective eggs present in the environment contaminated with dog feces. 1
Transmission Mechanisms
- Toxocariasis in humans is primarily caused by the larval stages of Toxocara canis (dog roundworm) and possibly Toxocara cati (cat roundworm) 1
- Eggs from these parasites are common environmental contaminants in areas where dogs and cats live or roam 1
- The eggs, present in dog feces, become infectious within weeks after being deposited in the environment (e.g., sandboxes, parks, yards, and beaches) 1
- Children are at higher risk due to their play habits, attraction to pets, and hand-to-mouth behaviors 2
Clinical Manifestations
- Toxocara larvae can migrate to various organs in humans, causing different clinical syndromes:
- Visceral larva migrans (VLM): affects internal organs like liver, lungs, and brain 1, 3
- Ocular larva migrans (OLM): affects the eyes, potentially causing permanent visual damage 2, 1
- Neurological toxocariasis: can cause meningo-encephalitis, epilepsy, and other neurological disorders 3
- Cutaneous manifestations: chronic urticaria, pruritus, and eczema 4
- Some infections may be asymptomatic or present with non-specific symptoms 1
Risk Factors
- Geophagy (soil eating) and close contact with pet dogs, particularly puppies, are principal risk factors 2
- Children's play habits and attraction to pets increase their risk compared to adults 2
- Poor hygiene practices after handling pets or playing in potentially contaminated areas 5
- Lack of regular deworming of pets 2
Prevention Strategies
- Hand washing is the single most important prevention step for reducing disease transmission risk 5
- Regular deworming of dogs, especially puppies, pregnant and nursing dogs 2
- Proper disposal of pet feces to reduce environmental contamination 2
- Minimizing children's exposure to potentially contaminated environments 2
- Supervising young children closely when around animals, especially in public settings 5
- For very young children, consider having adults carry them in animal areas or limit animal contact to over barriers 5
Special Considerations
- High-risk populations (children under 5 years, immunocompromised individuals, pregnant women) should take heightened precautions 5
- Dogs that hunt or have access to rodents pose additional risks 2
- Other parasites like tapeworms (Dipylidium caninum) can also be transmitted from dogs to humans, particularly through infected fleas 6, 7
Management of Infection
- Diagnosis is based on clinical presentation, blood tests, and detection of anti-Toxocara antibodies 3
- Treatment typically involves benzimidazole medications 3
- Early diagnosis and treatment are important to prevent serious complications 1
By implementing proper hygiene practices, regular pet deworming, and environmental management, the risk of Toxocara transmission from dogs to children can be significantly reduced.