Public health importance of vectors

Malaria, yellow fever, typhus fever, epidemic typhus, malaria, onchocerciasis, leishmaniasis, rabies and schistosomiasis are all communicable diseases prevalent in many countries. All of these are transmitted by vectors.

A number of diarrhoeal diseases (acute watery diarrhoea, dysentery, typhoid fever) can also be transmitted by vectors and are commonly observed among children in areas where sanitation is very poor. Diarrhoea alone kills many children before they get to their fifth year.

Vector-borne diseases not only cause illness, they also act as a barrier to development. Irrigation and dam workers will not be productive if they get malaria or schistosomiasis (bilharzia or snail fever). A person with malaria will need healthcare and will lose productive days at work. Some diseases like onchocerciasis (river blindness) have a devastating health impact. If onchocerciasis is left untreated the person could go blind. Additionally, vectors like rats destroy food and household materials and weevils damage cereals.

The public health importance of vectors can be summarised as follows:

• They cause illness that could be fatal or restrict working capacity.
• They damage food and household goods.
• They are a barrier to development.