In an Australian first, Sydney's Centenary Institute scientists have filmed a parasite infecting an immune cell, following the infection as it spreads.

The technology may help scientists identify molecules in the body responsible for the spread of infections and design vaccines to target them.

Professor Wolfgang Weninger and his colleagues have published their findings in the latest edition of the journal PloSPathogens.

Professor Weninger, head of the immune imaging program at the institute, said they could see how cells in the skin reacted to an infection for the first time.

''Scientists can now visualise the pathway of current vaccines in the immune system, providing greater understanding and the potential for refining current interventions against disease,'' he said.

The filming used high-powered multiphoton microscopy, which enables the study of live tissue compared with tissue removed from an animal.

The technology uses an infrared laser light, which scans the specimen at a cellular level.

It can record images of cells as small as 10micrometres in diameter, about one-10th the width of a human hair.

Professor Weninger used the technology to study dendritic cells in the skin of a mouse.

Dendritic cells, known as sentinels against pathogens, are part of the immune system.

They lie in wait for attacks by viruses or parasites and initiate the immune response against the invaders.

Under normal conditions, the researchers saw the dendritic cells in the top layer of the mouse's skin were static.

Below, in the second layer, the cells were ''very active, moving around as though seeking out pathogens''.

''Once we established this, it was fascinating to introduce the leishmania infection and watch as the parasite was picked up by the cells and the process by which it began to spread throughout the body,'' Professor Weninger he said.

Leishmaniasis affects up to 12million people in parts of Africa, the Middle East and South America. The disease causes skin sores and can affect internal organs such as the spleen, liver and bone marrow.

''We now have a general idea of how pathogens are recognised by the immune system and which cells are involved,'' he said.

''This means we can look at identifying the molecules responsible for the uptake of leishmania infection and these molecules could become vaccine targets. Additionally, we can investigate the immune responses of other infections which could lead to better vaccines.''