Combating tropical diseases


Goal 6  Combat HIV/AIDS, malaria and other diseases

Goal 6 aims to reduce the incidences of life-threatening diseases. More than one billion people - one in six people in the world - suffer from one or more of the diseases that the World Health Organization has called 'neglected tropical diseases'. These diseases can debilitate (weaken), deform, blind and kill. Here we share some practical advice about four diseases, one in each of these categories.

Much of the material in this article has been taken from Where There Is No Doctor: a village health care handbook for Africa by David Werner, with thanks to the publishers, Hesperian, for permission.


River blindness (onchocerciasis)

Cause  Worms spread by black fly

Early signs  

  • Itching
  • Pains in the back, shoulder or hip-joints, or general pains all over
  • Enlargement of the lymph nodes in one or both sides of the groin
  • Thickening of the skin with prominent pores like the skin of an orange
  • Painless lumps under the skin which are 2 to 3 cm in size, usually around the hips or chest

Later signs

  • The skin becomes gradually more wrinkled, like the skin of an old man.
  • The baby worms can invade the eye, causing eye irritation and eventually blindness.

How to prevent it

  • Seek out treatment early, before the eyes are affected.
  • Mass treatment with ivermectin (see below). 
  • Avoid sleeping out of doors, especially in the daytime, which is when the flies usually bite.


Ivermectin is the safest medicine, and one dose of tablets lasts for 6 to 12 months. It may be available free through the local health department.


Lymphatic filariasis

Cause  Parasitic thread-like worms spread by mosquitoes 


  • Painful swelling of a foot, rising up the leg to the groin and genitals. This gradually goes down.
  • Attacks of swelling come and go over several months, but the condition may eventually become permanent with 'elephantiasis' of the leg, and a big scrotum.

How to prevent it

  • Use a mosquito net
  • Mass treatment in areas where the disease is common (once a year for 4-6 years)
  • A person with repeated swelling should seek medical advice before the development of elephantiasis, which is much more difficult to treat


An experienced health care worker can advise on the correct dosage of the drug diethylcarbamazine, which will kill the worms and cure the early disease. Only surgical operations can help those with elephantiasis.


Bilharzia (schistosomiasis)

Cause  A parasitic worm that penetrates the skin when in contact with fresh water, and gets into the bloodstream, spread by urinating in or near water.

Note Another type of worm infects the gut and causes bloody diarrhoea. Stools are infected with worm eggs. Use latrines and never defecate near drinking water or where people bathe.


  • The most common sign is blood in the urine or in the stool.
  • Pain may occur in the lower belly and between the legs - usually worst at the end of urinating. Low fever and itching may occur.
  • After months or years, damage includes dangerous changes in the liver, or bladder cancer.

How to prevent it

  • Never urinate in or near water - use latrines instead
  • Do not wade through, wash or swim in infected water
  • Eradicate freshwater snails which act as a natural reservoir for the disease
  • Health education resulting in behaviour change


An experienced health care worker can give direction concerning medication. There are several drugs available - some more suitable for certain types of bilharzia than others.


Dengue fever

Dengue fever is most widespread in urban and semi-urban areas. It is not so common in rural areas. It has similar symptoms to flu but is more severe. A type called dengue haemorrhagic fever can cause death within 12-24 hours after the infected person experiences circulatory failure and shock. Most countries in Latin America and Asia are affected by dengue haemorrhagic fever and it is one of the main causes of death among children in Asia.

Cause  A virus spread by mosquitoes

Note If you suspect dengue fever, still test for malaria as the symptoms can look similar. Mistaking malaria for dengue fever can be fatal.


  • Sudden high fever with chills
  • Severe body aches, headache, sore throat
  • Person feels very ill, weak, miserable

After 3 to 4 days person feels better for a few hours to 2 days.

Then the illness returns for 1 or 2 days, often with a rash that begins on hands and feet.

The rash then spreads to arms, legs, and finally the body (usually not the face).

A severe form of dengue may cause bleeding into the skin (small dark spots) or dangerous bleeding inside the body.

How to prevent it 

  • Reduce mosquito breeding grounds
  • Use insect repellent, especially during an outbreak of dengue fever
  • Use a mosquito net
  • Wear clothing that covers as much of the body as possible


  • No medicine cures it, but if it is not severe, the illness goes away by itself in a few days
  • Rest, lots of liquids, painkillers (paracetamol but not aspirin)
  • In case of severe bleeding, treat for shock (see diagram)

What to do to prevent or treat shock

At the first sign of shock, or if there is a risk of shock:

  • Have the person lie down with the feet at a higher level than the head
  • Use a coat or blanket to keep the person warm, but not smothered
  • Do not give anything to eat or drink
  • Give lots of comfort and reassurance
  • Keep watch and seek medical help.