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In a region with a high prevalence of Angiostrongylus cantonensis, which preventative measure would be MOST effective in reducing human infections?
In a region with a high prevalence of Angiostrongylus cantonensis, which preventative measure would be MOST effective in reducing human infections?
- Administering prophylactic antibiotics to individuals at high risk of exposure.
- Promoting thorough cooking of mollusks and washing of produce. (correct)
- Implementing strict rodent control measures in urban and agricultural areas.
- Regular deworming of domestic dogs with broad-spectrum anthelmintics.
A patient presents with neurological symptoms and a history of recent travel to Southeast Asia. CSF analysis reveals eosinophilic pleocytosis but no visible parasites. Which of the following diagnostic tests would MOST strongly suggest Angiostrongylus cantonensis infection despite the absence of visible parasites in the CSF?
A patient presents with neurological symptoms and a history of recent travel to Southeast Asia. CSF analysis reveals eosinophilic pleocytosis but no visible parasites. Which of the following diagnostic tests would MOST strongly suggest Angiostrongylus cantonensis infection despite the absence of visible parasites in the CSF?
- PCR testing of CSF for *Angiostrongylus cantonensis* DNA. (correct)
- Stool examination for ova and parasites.
- Serological testing for antibodies against *Toxocara canis*.
- Liver biopsy to assess for granulomas.
Why is Toxocara canis infection more likely to cause blindness in children than in adults?
Why is Toxocara canis infection more likely to cause blindness in children than in adults?
- Children have a less developed blood-brain barrier, allowing easier access of the larvae to the central nervous system.
- Children are more prone to scratching their eyes, facilitating larval entry.
- Children exhibit more frequent eosinophilia, exacerbating retinal inflammation.
- Children have a higher likelihood of ingesting contaminated soil due to their play habits. (correct)
In both Toxocara canis and Angiostrongylus cantonensis infections, the larvae do not reach full maturity in humans, leading to disease manifestations. What immunological mechanism primarily contributes to this lack of larval maturation and subsequent pathology in human hosts?
In both Toxocara canis and Angiostrongylus cantonensis infections, the larvae do not reach full maturity in humans, leading to disease manifestations. What immunological mechanism primarily contributes to this lack of larval maturation and subsequent pathology in human hosts?
A researcher is investigating the prevalence of Toxocara canis in a population of domestic dogs. Which diagnostic method would provide the MOST accurate estimate of the overall infection rate in the dog population?
A researcher is investigating the prevalence of Toxocara canis in a population of domestic dogs. Which diagnostic method would provide the MOST accurate estimate of the overall infection rate in the dog population?
The use of Albendazole or Mebendazole is recommended for treating Toxocara canis. What is the primary biochemical mechanism by which these drugs exert their antihelminthic effects?
The use of Albendazole or Mebendazole is recommended for treating Toxocara canis. What is the primary biochemical mechanism by which these drugs exert their antihelminthic effects?
In cases of Angiostrongylus cantonensis meningoencephalitis, corticosteroids are sometimes administered as an adjunctive treatment. What is the rationale behind using corticosteroids in this context?
In cases of Angiostrongylus cantonensis meningoencephalitis, corticosteroids are sometimes administered as an adjunctive treatment. What is the rationale behind using corticosteroids in this context?
A research team is designing a study to assess the risk factors for Angiostrongylus cantonensis infection in a rural community. Which of the following study designs would be MOST appropriate for identifying potential sources of infection?
A research team is designing a study to assess the risk factors for Angiostrongylus cantonensis infection in a rural community. Which of the following study designs would be MOST appropriate for identifying potential sources of infection?
Visceral larva migrans (VLM) caused by Toxocara canis is characterized by larval migration through various organs. What is the MOST likely long-term consequence of VLM in a patient with severe, untreated infection?
Visceral larva migrans (VLM) caused by Toxocara canis is characterized by larval migration through various organs. What is the MOST likely long-term consequence of VLM in a patient with severe, untreated infection?
Which of the following statements regarding the transmission and life cycle of Toxocara canis and Angiostrongylus cantonensis is MOST accurate?
Which of the following statements regarding the transmission and life cycle of Toxocara canis and Angiostrongylus cantonensis is MOST accurate?
Flashcards
Definitive host of Toxocara canis
Definitive host of Toxocara canis
Dogs
Transmission of Toxocara canis
Transmission of Toxocara canis
Ingestion of infected eggs in soil
Treatment for Toxocariasis
Treatment for Toxocariasis
Albendazole or Mebendazole
Definitive host of Angiostrongylus cantonensis
Definitive host of Angiostrongylus cantonensis
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Intermediate hosts of Angiostrongylus cantonensis
Intermediate hosts of Angiostrongylus cantonensis
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Transmission of Angiostrongylus cantonensis
Transmission of Angiostrongylus cantonensis
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Condition caused by Toxocara larvae migrating through organs
Condition caused by Toxocara larvae migrating through organs
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Symptoms of Angiostrongylus cantonensis infection
Symptoms of Angiostrongylus cantonensis infection
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Immune response to Toxocara canis
Immune response to Toxocara canis
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How do humans get Angiostrongylus cantonensis?
How do humans get Angiostrongylus cantonensis?
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Study Notes
- Toxocara canis and Angiostrongylus cantonensis are parasitic worms.
Toxocariasis (Toxocara canis)
- The definitive host is dogs, while humans are accidental hosts.
- Transmission occurs through ingesting infected eggs in soil.
- Clinical symptoms include granulomas around dead larvae, blindness due to retinal involvement, fever, hepatomegaly, and eosinophilia.
- Diagnosis involves serological tests, hypergammaglobulinemia, and eosinophilia.
- Treatment includes Albendazole or Mebendazole.
Life Cycle of Toxocara canis
- Humans become infected by ingesting infected eggs or undercooked meat/viscera from infected paratenic hosts.
- After ingestion, eggs hatch, larvae penetrate the intestinal wall, and travel to various tissues including the liver, heart, lungs, brain, muscles, and eyes.
- Larvae do not develop further but cause local reactions and mechanical damage, leading to clinical toxocariasis.
- This condition is known as Visceral Larva Migrans (VLM), where Toxocara larvae migrate through organs (liver, lungs, brain) causing inflammation and damage.
Angiostrongyliasis (Angiostrongylus cantonensis)
- Also known as rat lungworm.
- The definitive host is rats, intermediate hosts are mollusks (slugs and snails), and humans are accidental hosts.
- Transmission occurs by ingesting infected mollusks or other intermediate hosts containing larval-stage parasites.
- Clinical symptoms include meningoencephalitis and ocular complications.
- Diagnosis involves detecting larvae and adult worms in cerebrospinal fluid (CSF) and peripheral eosinophilia.
- No specific treatment is available; patients recover spontaneously.
Life Cycle of Angiostrongylus cantonensis
- Humans acquire infection by ingesting raw or undercooked snails or slugs infected with the parasite, raw produce contaminated with small snails/slugs or their larvae, or paratenic hosts (e.g., crabs, freshwater shrimp) containing the larval form.
- In humans, larvae migrate to the brain (or rarely to the lungs), where they die, causing inflammatory responses.
Additional Information
- Granulomas form around dead larvae as the immune system tries to contain the infection.
- Blindness can occur due to retinal damage when larvae migrate to the eye (Ocular Larva Migrans, OLM).
- Fever is a systemic inflammatory response to the infection.
- Hepatomegaly is the enlargement of the liver due to larval migration and inflammation.
- Eosinophilia is a high number of eosinophils in the blood, common in parasitic infections.
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