A massive public health campaign in the UK and up to 200 countries around the world is being prepared by health chiefs to help guard against epidemics of infectious diseases during the 2012 Olympics and Paralympics this summer.

Measures already in place include what organisers call the biggest health surveillance system in the world – covering everything from UK advice lines to hospital intensive care units – to alert medics to the first signs of unusual illness.

At the other end of the scale, owners of small boats using the harbour and sea near the home of the sailing regatta at Weymouth will be warned not to release effluent into the water.

The NHS will be trying to help foreign visitors to the UK understand in advance how the health service here works – especially the NHS Direct and 111 advice lines. Senior officials "do not want everyone queuing up at A&E at 5pm", one said.

Brian McCloskey, London director of the Health Protection Agency (HPA), who is in charge of its Olympics operations, said there would be no need for a specific vaccination programme either for UK residents or people coming in.

"By and large it will be business as usual in terms of the public health services and people should just get on and enjoy the Games."

The agency is responsible for disease control and monitoring as well as scientific and public health advice during emergencies. Details of some of the health measures follow the announcement last month that up to 13,500 military personnel, two naval vessels, helicopters, RAF Typhoon aircraft and surface-to-air missiles will be on hand to deter or react to acts of terrorism.

Earlier this year, the Guardian revealed deep unease among senior officials at the HPA that the government was pl... Ministers later delayed its planned demise until 2013, with its role being replaced within a new executive agency with a wider public health role outside the Department of Health.

In the lead-up to the Games, the agency has been testing rapid alert systems to identify people with unusual symptoms or resistance to medicines who phone NHS Direct or attend A&E departments, are taken into hospital wards or intensive care units, or visit GP surgeries and drop-in clinics across swaths of the UK.

Rapid testing procedures have also been developed to identify bacteria or viruses that cause infectious diseases and scan foods for potential food poisoning bugs.

Cafes, burger vans and drinks and snack stalls throughout east London face spot checks on food hygiene and water quality, while Olympic arenas are already being monitored to ensure there is no danger of legionnaires' disease.

New empty buildings are notoriously susceptible to becoming potential breeding grounds for the Legionella bacteria responsible for this type of pneumonia.

The Games's swimming pools will be tested regularly for biological contamination with organisms responsible for gastrointestinal disease and open water used for events such as long-distance swimming, rowing, triathlon and sailing sampled to see if it is free of algae.

Extra precautions are also being taken in cities that host matches in the Olympic football tournament, including Cardiff, Manchester, Newcastle and Glasgow, or provide homes for competing nations' pre-Games camps.

The agency has led exercises to ensure it could still respond to a major emergency unrelated to the Olympics in another part of the country, such as a chemical explosion in north-east England.

Both the agency and the London Olympics organising committee (Locog) believe that among the most likely public health risks could be an outbreak of diarrhoea and vomiting in the athlete's village where most of the 17,000 athletes and officials from 200 countries will be based.

They are also well aware how even a small outbreak of that sort could put them under severe media and political pressure.

McCloskey said that although mass gatherings such as the Olympics did carry extra risks from infectious diseases, problems were not that common. "We will see the occasional incident of diarrhoea or food poisoning at the Games but we see these every summer anyway."

Experience garnered from other Olympic Games suggested that people could get "overexcited" in response to a disease outbreak, said McCloskey. "That is understandable. There are more people involved and the UK's national reputation depends on the Games."

Until now surveillance of seasonal flu outbreaks and potential pandemics such as bird flu and swine flu has depended on reporting by GPs. But the system for reporting unusual symptoms has widened to include acute hospitals. "One of the legacies we shall have [from the Games] is the most comprehensive surveillance system in the world," McCloskey said.

The Department of Health said: "The NHS has robust plans in place to prepare for any additional demands created by the 2012 Games.

"NHS organisations are working hard to ensure that they have plans in place so that the healthcare needs of local people are not compromised and that we also have high quality health services available to visitors. There is a comprehensive testing and exercising plan in place to make sure that all systems are ready for the Games."

Thousands of athletes will begin arriving in Britain for training camps in June. The Olympic village opens in mid-July and the Olympics run from 27 July to 12 August. The Paralympics run from the end of August into September.

On the busiest day – Saturday 4 August – 700,000 ticket holders will be moving around London to watch sessions at 11 venues. About 300,000 people will be around the Olympic Park alone on some days of the competition.

In all, 8.8m tickets have been made available for the Games, with 6.6m going to the general public.

Confirmation of the plans to the Guardian coincided with a series of six articles in the Lancet medical journal calling for more public health lessons to be learned from mass gatherings, ranging from the Hajj pilgrimages to Mecca to music festivals and global sports events. Incidents range from unusual concentration of diseases, heatstroke and even stampedes.

Ibrahim Abubakar, head of the HPA's TB section and author of one of the articles, said lessons learned in planning for the Olympics and other events could be crucial to reducing transmission of disease between different countries . "New audiences can take away public health messages when they return," said Abubakar.