Hook worm infestation continues to be a major cause of chronic anemia and deaths in developing tropical countries. About 576-740 million people worldwide are said to be affected by hook worm infestation.
It is a nematode affecting health of some animals like cats and dogs and also affects humans. The eggs stay and hatch in warm sandy soils. In a person walking bare footed, larvae can penetrate the bare skin through hooks present on its mouth, from where it has derived its name. They grow into adult worms inside human body and pass through blood vessels to the lungs and wind pipe from where they are swallowed.
On reaching the intestines, they suck blood vigorously through the mucosa. The worms can remain there from months to years. This results in chronic blood loss leading to wasting of the affected individual. Eggs are passed in the feces of the infected person, where they hatch and another individual can be affected. Due to chronic blood loss, resistance of the body is reduced making it more susceptible to infections. Women suffer more because they are more prone to anemia due to other reasons also. Co-infection with malaria and hook worm in individuals in tropical developing countries adds to sickness and deaths among individuals.
It is an occupational hazard for persons working in fields. Infection is maintained in the environment due to ignorance and lack of protective measures among people.
Due to hook worm infestation, there may be itching and allergic reaction at site of infestation. As the larvae reach the lungs, one may have dry cough. After reaching intestines and getting embedded in the intestinal mucosa, these tend to cause abdominal discomfort, pain and nausea. Frank blood is not visible in stools, though due to sucking of blood by the parasites one gradually becomes anemic and malnourished.
During pregnancy, hook worm infestation can cause abortions and intrauterine growth retardation. Studies have shown hook worm infection to be passed on in breast milk from affected mother to child due to hormonal changes occurring during delivery. This is the reason for infants as young as one month old to be infected by hook worm and die. Children affected by hook worm infestation have been proven to suffer from intellectual impairment and growth retardation. Thus, it is not a problem of individuals alone but of the entire community, affecting the present as well as future generation.
Blood lost is not frank, hence cannot be visualised by naked eye. Therefore, a person is not even aware of the infested state unless he becomes very sick due to the resultant anemia. Blood test done may reveal high percentage of type of white blood cells indicating allergy in the blood, which gives a clue to the parasitic infection. But diagnosis is confirmed by seeing the typical eggs in the stool of the affected person.
Treatment is by antihelmenthic drugs like albendazole, mebendazole.
Mass awareness about hook worm infestation and preventive measures can bring down the burden of sickness caused due to hook worm. People working in fields should be advised to wear thick shoes. Defecation in open fields should be discouraged. Night soil should not be used for manure for crops and vegetables. Regular deworming of pet animals also helps to prevent some type of hook worm infestation which can spread from dogs to human beings.
In Rwanda, deworming of children is done on a regular basis by giving them anti-helmenthic medicines. This prevents against parasitic infestations, including that of hook worm. This is very useful as it would be helping to reduce the sickness among children due to worm infestations.
Soil of any area suspected to be contaminated with eggs and larvae of hook worm can be treated with borax powder or brine solution (1.5 pounds of salt/gallon of water) to eradicate hook worms.
Dr Rachna Pande is a specialist in internal medicine