Note that all persons included in your visa application will need to pass the "dependency' test & medical examinations. If any person included fails the medical test this will mean the entire application will fail 'one fails = all fails' policy. If a person fails the dependency test then they can be removed from the application and the application can still be approved.
Certain health conditions may affect your Australian migration or residency application -- for example, HIV, cancer, active tuberculosis (TB), or Hepatitis. The Department of Immigration requires all visa applicants to undergo a medical examination by a doctor approved by the relevant Embassy before a visa can be granted.
The health criteria each require that an applicant:
Is free from tuberculosis.
Is free from a disease or condition that is, or may result in the applicant being, a threat to public health in Australia or a danger to the Australian community.
Is not a person who has a disease or condition that would be likely to: result in a significant cost to the Australian community in the areas of health care or community services.
Any medical condition which will cost of AUD$20,000 to treat (medicine, hospitals etc) throughout the life time of the visa applicant (after visa grant), will be considered a significant cost. People with any serious medical conditions can expect to encounter delays with their visa application, and if not handled properly, potential failure.