Life History of Ancylostoma Duodenale {Hookworm}

.Habitat and Distribution

Hookworm is a coelozoic endoparasitic nematode found in the small intestine of man especially in the jejunum, less often in the duodenum and rarely in the ileum|it is widely distributed in all tropical and subtropical countries, especially in the rural areas of Southern europe, North Africa and Asian countries like India,Sri Lanka and North China| About 25% of the world population is infected by hookworm|It feeds upon the blood and intestinal tissues|.


Hookworm is elongated and cylindrical| sexes are unisexual or dioecous and show sexual dimorphism |The size of male hookworm is about 8 mm in length| The posterior opening are cloacal aperture, has copulatory spicules and Copulatory bursa are present at posterior end and is supported by muscular rays| The size of Female hookworm is about 12.5 mm in length| The posterior opening are anus, with no copulatory spicules| The Copulatory bursa are posterior end tapers into a post anal caudal spine| It has no copulatory bursa| Anterior end of both the sexes have a large buccal capsule having six cutting plates or teeth, so is called hookworm|The teeth help in attachment of the worm with the intestinal wall of the host|

.Life Cycle

Hookworm is a monogenetic nematode| Copulation occurs in the intestine of the host| Fertilization is internal and occur in the seminal receptales of female| Female is oviparous and lays the capsules in the intestine of host at the rate 9,000 capsule per day| Capsule are finally egested out with faeces. In open, the zygote develops into first juvenile stage called RHABDITIFORM larva inside the capsule | Rhabditiform larva hatches out of capsule in the soil, feed on bacteria etc and undergoes two moults to form an infective filariform larva|


The filariform larvae penetrate through the skin of foot or hand and reach the intestine after taking following path larvae,skin,subcutaneous tissue, lymphatic, venous system,right side of heart,pulmonarycapillaries,Alveoli,Respiratory tract, pharynx, digestive tract, Intestine|

. Disease And Symptoms

Heavy infection of hookworm causes ANCYLOSTOMIASIS which is characterized by gastro intestinal dysfunctioning severe anaemia [ causing bleeding wound in the intestine ] and physical and mental deficiency | Migratory larvae may cause haemorrhage and bronchial pneumonites in the lungs| In several cases, men may become impotent while women may cease to menstruate|


1.proper disposal of human faeces through underground sewage system|

2.Feet and hands should be protected from coming in contact with soil|


Effective drugs used against ancylostomiasis are carbon tetrachloride, thymol, oil of chenopodium,hexylresorcinol,tetrachloroethylene|

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