Zero HIV patient probably flew to New York from Haiti in 1971

Zero patient (index patient) - this is how people in medicine call the person who started the epidemic. This is the very first infected individual.

For example, take the global HIV epidemic, which has affected almost all countries and claimed the lives of more than 25 million people. Every day, 14 people die from this disease, and about 42 million live with the virus. Although the infectious disease is now well studied, but the rate of its spread is still high, the number of infected and the number of deaths is growing.

For a long time it was believed that the global HIV epidemic began with a single male with a different sexual orientation, Gaetan Dugas, in the photo. He was called the patient zero. Now an international team of scientists conducted a genetic study of early HIV samples and found out some details about how things really were.

Gaetan Dugas (1953−1984) gained universal fame as a zero patient after the publication in 1987 of the book "And the Orchestra Continued to Play" journalist Randy Shilts. The author of the book figuratively called the hero “zero patient” for his promiscuous sex life, which caused thousands of people to get the infection — and it was impossible to stop her in the United States. Gaetan worked as a flight attendant for Air Canada and was just perfect for the rapid spread of infection throughout the country.
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The view that Gaetan Dugas is a zero patient has become widespread in the community. But scientifically it is not. Before him were still infected people, from which Gaetan received the virus.

The results of a genetic study published a group of scientists under the leadership of evolutionary biologist Michael Vorobey (Michael Worobey). She found out that Dugas could not be a zero patient in the USA. The initial infection occurred at another time and in another place.

Until recently, scientists had the only genome of a patient with HIV-1, dated before 1980, and this patient was from Africa. At the same time, doctors were inclined to believe that the global HIV epidemic began in the United States. But the study of this topic was hampered by the absence of the genomes of infected patients. To fill this gap, Michael Sparrow and his colleagues screened and sequenced serum samples taken from homosexual patients from New York and San Francisco in 1978−1979. At that time, no one knew about HIV, but gay samples were taken for hepatitis B, and the serum has survived to this day.

Of the 2231 samples, 83 were positive for HIV-1. Twenty of them underwent genome sequencing. Researchers improved the technique to greatly increase the likelihood of detecting HIV-1 in samples and to extract the complete genomic sequences of HIV-1 from them. Five samples from New York and three from San Francisco provided enough data to assemble the genome, that is, combining large numbers of short DNA into a long sequence. A Bayes phylogenetic analysis of these HIV-1 genomes was performed. The result is shown in the diagram.



The analysis showed that although these samples are the oldest samples outside Africa, they are not in contact with the main branch even for subtype B (this virus subtype dominates in Europe and the USA, while subtype A dominates in some regions of Africa). Instead, the American HIV genomes of the 1970s and the entire American epidemic generally phylogenetically branched off from a more genetically diverse and old subtype B epidemic in the Caribbean countries - Haiti, Dominican Republic, Trinidad and Tobago, Jamaica. HIV-1 specimens taken from Caribbean émigrés are marked in gold in the diagram.

Based on the available data of phylogenetic analysis, scientists concluded that the Caribbean HIV-1 samples are ancestors of the US (99% probability) and originate from an ancestor from the 1963−1970 interval (95% probability). All this allows us to confidently enough assume that the HIV epidemic has come to America from the countries of the Caribbean, and not vice versa.

Geographical analysis and dating of HIV-1 samples by molecular clock allows us to fairly accurately predict the date when HIV came from the Caribbean in the United States. This probably happened in 1971, long before blood samples were taken, which are now being analyzed by experts.

The following chart shows the dates of the estimated infection by molecular clock and the estimated route of HIV spread. Scientists suggest that the virus came from Africa to Haiti (the date of this transition is unknown). From Haiti, he came to New York, from there spread throughout the United States and around the world.

However, flight attendant Gaetan Duga was completely unaffected, so his memory can be considered purified from dirty insinuations. Zero patient was not him.


Cluster of sexual contacts 40 patients infected with AIDS at the beginning of the spread of infection. Zero patient is indicated by the number 0 (index patient)

The beginning of the spread of HIV infection occurred in New York and San Francisco in 1971, at the height of the sexual revolution , under the slogans of the hippie movement. People who believed in beauty and freedom were very loving - and many were victims of the deadly virus.

The scientific work was published on October 26, 2016 in the journal Nature (doi: 10.1038 / nature19827, pdf ).