148 



THE AUSTRALIAN MUSEUM MAGAZINE. 



A Papuan village on piles, over salt water. Settlements like this are 



Hookworm scourge. 



practically free from the 



individual. Ilundrt'ds of hookworms are 

 sometimes found in one i>erson, and from 

 five to eight hundred were removed from 

 each of several children in the Tweed 

 River region. 



Unfortunately hookworms damage their 

 human hosts. They cling to the intes- 

 tinal wall by their mouths, armed with 

 booklets or cutting plates, and feed on 

 the lining of the bowel and its juices. 

 This causes little illcers and destroys the 

 body tissue, and the worms also produco 

 a poison, which is probably injected into 

 their hosts through structures in their 

 mouths. 



The effects of the hookworms on man 

 are gradual in onset, and so mucli Uke 

 those of other chronic diseases that the 

 condition is often not recognised, and the 

 sufferer loses his oppoi'tunity of a rapid 

 and ear]y cure through the removal of the 

 worm. The outstanding effect of the pre- 

 sence of the hookworm is pallor, due to a 

 reduction in the amount of red colouring 

 matter in tlie blood, and with this anaemia 

 we find in children a retardation of growtli 

 both physical and mental. Sometimes 

 severely infested persons develop an ab- 

 normal appetite for earth or clay, and 

 are known as earth eaters, but this is not 

 conunon in Australia. The anaemia is 

 apt to be accompanied by lack of ambi- 

 tion, weakness, and increased suscepti- 



bility to infectious diseases, and in severe 

 cases death may occur. 



To find their way into living animals 

 parasitic nematodes have to overcome the 

 defences of the body against invasion, 

 such as the digestive juices of the aliment- 

 ary tract and the outside covering oF 

 skin. Some enter through being swal- 

 lowed as eggs, and depend for protection 

 on envelopes that resist digestion. The 

 larvae of others, for example filaria, are 

 injected beneath the skin of their host by 

 mos(|uitos. Others, including the hook- 

 worm larvae, have developed the ability to 

 \vriggle through the outside skin and take 

 a devious course to their destination in 

 the intestines. 



It is a fortunate circumstance that in 

 the case of the hookworm, ]iart of its life 

 cu'le must still be siK^nt outside the body 

 of its animal host in the habitat of the 

 early nematodes, moist earth. The eggs 

 cannot hatch in the digestive tract, and 

 infestation can take place only if the eggs 

 hatch in- the ground and the developed 

 larva gains access to the body through tlie 

 .skin, the usual way, or through the rare 

 accident of being SAvallowed at the proper 

 stage of development. Thus if no hook- 

 worm eggs reach the ground there will be 

 no hookworms, and man can protect him- 

 self from infection hi/ proper treatment 

 and disposal of seivage. Discharge of 



