ON World Health Day, the World Health Organization (WHO) draws attention to a major public health problem and what needs to be done to address it. This year’s theme is "Small bite, big threat” and this references vector-borne diseases.

Vector-borne diseases include malaria, dengue, leishmaniasis, Lyme disease, schistosomiasis and yellow fever that are carried by mosquitoes, bugs, ticks, flies, freshwater snails and other vectors.

Schistosomiasis, or bilharzia is the most widespread of all vector-borne diseases and is transmitted via freshwater snails. Transmission can occur from contact with all freshwater from canals, rivers, streams, ponds or lakes.

Schistosomiasis is especially prevalent in poor communities without access to safe drinking water and adequate sanitation. It often affects farming and fishing populations as well as women doing domestic chores in infested waters, such as washing clothes.

Most people have no symptoms early in the infection but many develop itchy skin and a rash within days. Fever, chills, cough and muscle aches can follow and occur within 1 to 2 months after infection.

Poor personal hygiene and play habits make children especially vulnerable to the parasites. Schistosomiasis can be effectively controlled through regular mass treatment of high-risk groups with safe and effective medicines.

Deaths from mosquito-borne malaria has been reduced by 45 per cent globally and by 49 per cent in Africa – saving an estimated 3.3 million lives since 2000. But more needs to be done. In sub-Saharan Africa, well under 50 per cent of the population has access to insecticide-treated bed nets.

"This remarkable progress is no cause for complacency: absolute numbers of malaria cases and deaths are not going down as fast as they could,” says Dr Margaret Chan, WHO Director-General. "The fact that so many people are infected and dying from mosquito bites is one of the greatest tragedies of the 21st century.”

When a mosquito bites an infected person, the mosquito becomes the carrier of microscopic malaria parasites. When the mosquito bites again, these parasites mix with the mosquito’s saliva and are injected into the new person.

According to the WHO, half of the population is at risk of being infected – especially pregnant women and young children. Malaria co-infection is another major concern and occurs when two or more diseases are present at the same time. Pregnant women who have co-infection of HIV and malaria often suffer from anaemia, pre-term birth and low-birth weight babies.

"To win the fight against malaria we must get the means to prevent and treat the disease to every family who needs it,” says Raymond G Chambers, the United Nations Secretary General’s Special Envoy for Financing the Health MDGs and for Malaria. "Our collective efforts are not only ending the needless suffering of millions, but are helping families thrive and adding billions of dollars to economies that nations can use in other ways.”

You can protect yourself and your family against malaria and other vector-borne diseases by taking simple measures that include:

* Avoid going out between dusk and dawn when mosquitos are most active;

* Wear long-sleeved, light-coloured clothing and long trousers;

* Use insecticide-treated nets in bedrooms at night;

* Apply insect repellent on any exposed skin and use indoor residual sprays in the home;

* Get rid of stagnant water from places where mosquitoes breed, such as old containers, flower pots and used tyres.

Dr. Cory Couillard works in collaboration with the World Health Organization’s goals of disease prevention and control.

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