Toxocara canis (Visceral larva migrans)

A 7-year-old boy is brought to the physician due to abdominal pain and vomiting. The patient's symptoms started 5 days ago. Last week, he returned from a family trip to Mexico, during which they visited a zoo and several national parks. However, none of the patient’s family members have similar symptoms. Temperature is 38.5°C (101.3°F), blood pressure is 105/70 mmHg, and pulse is 68/min. On physical examination, abdominal tenderness and hepatosplenomegaly are noted. Laboratory findings reveal significant eosinophilia. The physician suspects a nematode infection that is transmitted via the fecal-oral route. Which of the following is the most likely cause of this patient’s condition?