H1N1: A "rapidly fatal" form of the disease

The people who died from influenza H1N1 had contracted a form of "rapidly fatal" disease, which kills but in different ways, according to a study published Thursday in the United States.

Researchers have studied the cases of 21 patients aged one to 68 years, died in July and August in Sao Paulo, Brazil, due to influenza H1N1.

All these 21 patients "showed a progressive form and rapidly fatal disease," according to the study published in the American Journal of Respiratory and Critical Care Medicine.

All these patients died from severe lung lesions, but these lesions were of three types, according to the study, which concludes that the H1N1 flu "killed in different ways."

"Some patients died only due to severe lung lesions, but others had bronchiolitis or bleeding," says Thais Mauad, associate professor in the Department of Pathology of the University of Sao Paulo and the lead author of the study.

"It is important to bear in mind that patients with prior health problems must be properly monitored because they have an increased risk of severe infection with H1N1,"  Thais Mauad said.

Sixteen of 21 patients studied by his team suffered from chronic health problems like heart disease or cancer.

The researchers also discovered an "aberrant immune response" in some patients, which suggests that an exaggerated inflammatory response caused by viral infection could escalate and damage lung tissue, causing severe lung damage and kidney failure.

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