In a letter to the scientific journal Nature in 1990, Robert F. Garry stated that efforts to directly detect HIV DNA were under way: "Proviral DNA has recently been detected in his tissues by PCR in collaboration with J. Sninsky and S. Kwok (Cetus Corporation, Emeryville, California) but nucleotide sequence analysis is not yet complete." A study which reported the results of testing for HIV DNA was eventually presented nearly a decade later, as a conference abstract in 1999. The abstract reports the detection of HIV genes in Rayford's samples which were very similar to the HIV IIIB isolate which was discovered in France in the 1980s, and became widely used as a laboratory reference isolate (this study has never been published in a peer-reviewed scientific journal). Neither John Sninsky nor Shirley Kwok was listed as an author on the abstract. The abstract argues that laboratory contamination by the HIV IIIB isolate was unlikely because the DNA testing was done on Rayford's samples without being cultured. The last known tissue samples of Rayford were in a New Orleans lab and inadvertently destroyed during Hurricane Katrina in 2005, preventing further testing. Impact on AIDS origin research Rayford never traveled outside the Midwestern United States and told doctors that he had never received a blood transfusion. If Rayford was indeed infected with HIV, as one group of researchers claims, the mode of acquisition is assumed to have been through sexual contact. Having never left the country, the researchers who claim that Rayford represented an early case of HIV infection presume that AIDS may have been present in North America before Rayford began to show symptoms of it in 1966. Rayford never ventured into cosmopolitan cities such as New York, Los Angeles, or San Francisco, where the HIV-AIDS epidemic was first observed in the United States. The only notable international connection to St. Louis is that it was TWA's main airline hub. Doctors and others who investigated the case in the early 1980s speculated that Rayford may have been sexually abused or a victim of child prostitution. See also Arvid Noe, the earliest known European AIDS case Index case History of HIV/AIDS Timeline of early AIDS cases Timeline of HIV/AIDS References 1953 births 1969 deaths Index cases African-American people American children Deaths from pneumonia in Missouri AIDS-related deaths in Missouri HIV/AIDS in the United States People from St. Louis