Hookworms (infective larvae) enter the body, usually the feet, by penetrating the skin. Ancylostoma may also be acquired by the oral route by direct ingestion of infective larvae via contaminated fruits and vegetables. Transmission is perennial in many tropics. In cooler and drier climes, transmission may take place in the warmer and wet seasons.
Incubation Period (Pre–patent Period) Following infection, the pre–patent period for N americanus is seven weeks while that for A. duodenale is unpredictable, ranging from five weeks to nine months. This is because the invading larvae of A duodenale is capable of remaining arrested or dormant in the tissues of the host for as long as nine months, and then again resume development and migrate.
Clinical Features Individual Hookworm infection cause chronic blood loss and depletion of body’s iron stores leading to iron–deficiency anemia. This has implications for child health in terms of retarded physical growth and development, for the health of mothers in terms of increased morbidity, low birth weight babies, abortion, stillbirths and impaired lactation, and for the health of adults in terms of diminished capacity for sustained hard work. Hookworm infection also cause a loss of blood plasma into the small intestine which can lead to hypoalbuminaemia in some subjects.
Community Hookworm infection exerts a significant and harmful effect on various aspects of the economy and the quality of life of a community, especially in three major areas. These are nutrition, growth and development work, and productivity and medical care costs.