The Ministry of Health in China recently reported the country’s 18th case of human infection with the H5N1 avian influenza virus. More than 30 countries have now registered the flu’s presence, and the question of how to react to a pandemic is spreading even faster. The answer is as simple as washing your hands often and as complicated as figuring out how to operate essential services and communicate with a fearful public when a third of the population is ill with the flu.

Maine has kept pace with other states in assembling its emergency plans and today is expected to begin a one-stop Web site for information on avian, pandemic and seasonal flu – www.maineflu.gov – a useful step forward. But a recent story in The Washington Post points out that businesses are struggling to get ready, in part because of the scale of the problem.

For instance, manufacturers that rely on parts from overseas may find their production lines shut down, which in turn affects distributors and retail outlets. The Post points to Canada’s experience with severe acute respiratory syndrome (SARS). Though Canada suffered only about 40 deaths, it caused a 14-week emergency that quarantined 30,000 people and cost Toronto $1 billion in lost business.

The possibility of suffering and death among even a small minority of the population is plenty frightening for anyone to pay attention to this issue, but the outside chance that the normal functioning of society for everyone will be affected brings a new set of questions. How will public transportation function? What about financial institutions? What about, gulp, the media?

Meanwhile, individuals who are worried about a pandemic have a fairly simple protocol to follow:

. Have an emergency supply on hand of food, water, batteries and other necessities for your family to live in isolation for three to five days. Maine calls this an all-hazards kit, and it may be useful in the event of a pandemic.

. Wash your hands and cover your coughs, says Maine’s health director, Dora Mills. Staying out of the line of fire of others who are coughing and sneezing would also matter. Relatedly, if you’re sick, stay home.

. Get a flu shot. It won’t protect against the bird-flu strain, H5N1, but can help against other strains that are more common and could help you better fight H5N1 if you do catch it.

. Develop a plan for who would be contacted through what telephone numbers or e-mail if an outbreak did occur and where the family would seek treatment.