Males and females are equally susceptible to hookworm infection.Ī hookworm (Ancylostoma caninum) egg via microscope at 1000x.
Studies from China and Brazil indicate a consistently increasing prevalence, from 15% at age 10 years to 60% at age 70 years and older egg counts in stool also increase in a similar pattern.
In endemic areas, the highest prevalences are reported among school-aged children and adolescents, possibly because of age-related changes in exposure and the acquisition of immunity.
In 2010, it was estimated that 117 million individuals in sub-Saharan Africa were infected with hookworms, as well as 64 million in East Asia, 140 million in South Asia, 77 million in Southeast Asia, 30 million in Latin America and the Caribbean, 10 million in Oceania, and 4.6 million in the Middle East and North Africa.
Infection is most prevalent in tropical and subtropical zones, roughly between the latitudes of 45°N and 30°S in some communities, prevalence may be as high as 90%.
Human infection with A duodenale or N americanus is estimated to affect approximately 472 million people worldwide.
Cutaneous larva migrans is endemic in the southeastern states and Puerto Rico the canine hookworm A caninum has reportedly caused eosinophilic enteritis in Australia and the United States.
Hookworm infection and disease are now most likely to be found in immigrants, refugees, and adoptees from tropical countries.
Worldwide, hookworms infect an estimated 472 million people.
In 3-5 weeks, the adults become sexually mature, and the female worms begin to produce eggs that appear in the feces of the host.
The larvae migrate through the dermis, entering the bloodstream and moving to the lungs within 10 days once in the lungs, they break into alveoli, causing a mild and usually asymptomatic alveolitis with eosinophilia.
元 live in the top 2.5 cm of soil and move vertically toward moisture and oxygen.
These 元 go through developmental arrest and can survive in damp soil for as long as 2 years however, they quickly become desiccated if exposed to direct sunlight, drying, or salt water.
The rhabditiform larvae feed on the feces and undergo 2 successive molts after 5-10 days, they become infective filariform larvae or 元.
Larval growth is most proliferative in favorable soil that is sandy and moist, with an optimal temperature of 20-30☌ under these conditions, the larvae hatch in 1 or 2 days to become rhabditiform larvae, also known as L1.
These larvae are developmentally arrested and nonfeeding if they are unable to infect a new host, they die when their metabolic reserves are exhausted, usually in about 6 weeks.
After deposition onto soil and under appropriate conditions, each egg develops into an infective larva.
Each day in the intestine, a mature female A duodenale worm produces about 10,000-30,000 eggs, and a mature female N americanus worm produces 5000-10,000 eggs.
Life Cycle of A Hookworm | CDC – Department of Parasitic Diseases