VisitorsHealthInsurance.com has Pre-existing Condition Visitor Insurance Plan to cover acute onset of Pre-existing Conditions while visiting USA. Pre-existing conditions? If you have been seen by a doctor and might need medical care or drugs for that same issue again read this section of the policy carefully. It will define a pre-existing condition according to what the problem was, how long ago you were seen for it, and when it manifested itself, and it will tell you when, if ever, it will cover your care for this condition. There might be a waiting period, you may have to pay extra, or it may include only limited coverage for a sudden recurrence. It is easy for an insurance company to take a look at your medical records obtained from the physician and find out that you had a pre-existing condition.