What is the mode of transmission for Ancyclostoma duodenale and Necatur americanus?

The correct mode of transmission for Ancyclostoma duodenale and Necatur americanus is through the larvae invading the skin from soil. These parasites are commonly known as hookworms and are primarily transmitted when larvae in contaminated soil come into contact with the skin, usually when individuals walk barefoot on infected ground.

This transmission route is significant because the larvae penetrate the skin and enter the host's bloodstream or lymphatic system, eventually traveling to the lungs and then being swallowed, which allows them to reach the intestines where they mature into adult worms. This life cycle is essential for their survival and for causing infection in humans.

While contaminated water and inhalation of spores are common modes of transmission for other pathogens, they do not pertain to these hookworms. Ingestion of contaminated food typically relates to different types of gastrointestinal parasites. Thus, recognizing that hookworm infections occur through dermal penetration by larvae emphasizes the importance of wearing shoes in endemic areas and maintaining good sanitation practices.