Image caption Malaria, spread by mosquitoes in tropical areas, is one of the world's biggest killers

The number of malaria infections recorded among UK residents has increased by nearly 30% over the past two years.

New figures from the Health Protection Agency (HPA) reveal there were 1,761 new cases in 2010.

Over the past decade most infections have occurred among people who visited West Africa or South Asia.

The HPA is warning travellers to heed advice on how to avoid malaria, which is the world's second biggest killer.

In 2008 there were 1,370 new cases but the following year the numbers increased to 1,495.

In 2010, almost 40% of UK residents who contracted the disease had visited either Nigeria or Ghana, while 11% had been to India.

Travellers at risk

The HPA believes these travellers may not have sought or were unable to access advice on malaria prevention or had not thought they were at risk because they knew the area they were travelling to.

And these kind of travellers appear to be more at risk because they generally stay for longer than other visitors, such as those on business.

It is a myth that people who have had malaria will not get it again Dr Jane Jones, Health Protection Agency

They also tend to stay with friends and family rather than in hotels or resorts, and so are exposed to the same risk of contracting the disease as local people.

Professor Peter Chiodini, who heads the HPA's malaria reference laboratory, said the figures - released on World Malaria Day - are a timely reminder for travellers to take precautions against the disease.

"Anyone who is travelling to a country where malaria is present should take travel advice and appropriate medication.

"Even people living in Britain visiting the country in which they were born or grew up, or have previously visited, are not immune from malaria and should take precautions."

Second biggest killer

Malaria is a devastating disease in the developing world, accounting for 20% of childhood deaths in Africa.

Malaria facts There are several different types of malaria, but most deaths are caused by Plasmodium falciparum

Malaria is the world's second biggest killer after tuberculosis

Malaria is spread by mosquito bites

It cannot be spread directly from human to human

A billion of the world's population is at risk

In 2008, 247 million cases of malaria with almost 1 million deaths were recorded

The societies and economic development of the world's poorest nations are severely affected

Only tuberculosis kills more people worldwide.

Malaria is spread by mosquitoes in tropical areas but it cannot be transmitted directly from person to person.

The symptoms include a flu-like illness, fever, shaking, headache, muscle aches and tiredness, as well as nausea, vomiting and diarrhoea.

Dr Jane Jones, head of the HPA's travel and migrant health section, says while malaria is a potentially deadly disease, it is also one that is almost completely preventable.

"Anyone who is planning to travel to a tropical destination should always seek advice from their GP or travel health clinic before their trip.

"It is a myth that people who have had malaria will not get it again.

"Our advice is the same for all travellers - you must take anti-mosquito precautions and medication to keep safe."