Organism, Causative agent, Etiologic agent
Hookworm is most commonly caused by the intestinal nematode Ancylostoma duodenale but may also be caused by Necator americanus. Both these worms belong to a class of parasites often referred to as “soil-transmitted helminths”.
Transmission occurs by exposure of bare skin to soil infested with A. duodenale or N. americanus larvae via percutaneous (skin) penetration. Oral transmission can sometimes occur from consuming improperly washed food grown in or exposed to contaminated soil. Transmission can also occur, albeit rarely, between a mother and her fetus/infant via infected placental or mammary fluids. Soil becomes contaminated when eggs are shed in an infected person's feces and exposed to a warm, moist, soil environment where they mature into larvae and become infectious. Human to human transmission of hookworm does not occur.
Most hookworm infections are asymptomatic. Immediately following infection a pruritic, erythematous, papular rash commonly known as “ground itch” can develop at the penetration site, typically the feet or hands. In the first two weeks of infection, minor cough and throat irritation may occur as a result of larval migration but these symptoms are rare. Light infections produce few or no symptoms but can include abdominal discomfort, diarrhea, and/or blood in the stool. Severe infections can be characterized by more severe symptoms stemming primarily from intestinal blood loss resulting in anemia. Symptoms can include: nausea, fatigue, pale skin, and rarely congestive heart failure and death. In children, anemia resulting from infection can cause impaired growth and delayed mental development.
The best method for prevention of hookworm is proper disposal of human waste. Wearing shoes while outside, or other protective clothing such as gloves, pants, long sleeves etc. prevents hookworm larvae from penetrating the skin. Rapid identification and treatment of anyone infected with hookworm will help decrease environmental contamination. Avoiding the use of human waste-based fertilizer (night soil) and thoroughly washing hands and all produce before cooking and eating is also highly recommended in order to prevent ingestion of parasite eggs.
Hookworm is a reportable condition as of 2016 and has since only reported 8 cases in 2018 and one case in 2020.