Cuevas et al. , in their article ‘High HIV-1 genetic diversity in Cuba', published in AIDS in August 2002, without the approval of the Cuban authors, made several affirmations and inferences that should be commented upon.
They reported that the results were a reflection of what really occurs in the HIV/AIDS population in Cuba; however, they did not take into account that the sample under study was a convenience sampling that was taken to represent different modalities of therapy in the country, and to include in a deliberate way, individuals with known non-B subtype for resistance behaviour observation when therapy was applied, which has previously been analysed but was not included in the discussion of the report.
Most of the non-B subtype individuals included had already been detected in previous studies by heteroduplex mobility assay, a technique used in Cuba since 1997 as a tool for the surveillance of circulating forms. Such studies, performed out of the convenience sampling representative of the HIV-1 population in Cuba, showed a predominance of subtype B (70%), whereas a lower rate of subtypes A and C were also found (12.9 and 17.1%, respectively) . Recent studies performed by heteroduplex mobility assay env/gag have demonstrated the circulation of new subtypes and recombinant forms for the env/gag genes, but in smaller proportions if compared with subtype B, which continues to prevail in the country .
The report of Cuevas et al.  was based on a survey carried out during 1999 on 105 HIV-infected individuals, representing 3.2% of the seropositive population detected in the country up to 31 December 2000 . Although the quantity of individuals enrolled in the study could be acceptable with respect to the HIV/AIDS-infected population in Cuba, we insist that the sample was not taken at random. This aspect was previously pointed out by a referee of the Pan American Journal of Public Health in another publication, derived from the data on resistance mutations obtained from a study conducted on the same sample .
We also disagree, because of the lack of a scientific basis, that the appearance of new circulating recombinant forms (CRF) constitute a threat to other countries in the region.
The results obtained from that study arose from the characteristics of the sample, which mostly included individuals who had been diagnosed more than 3 years earlier, indulged in high-risk sexual behaviour, lacked adherence to the antiretroviral regime indicated, and even included some cases of therapeutic failure, all of which are factors that enable the appearance of new CRF that are not present in other HIV-infected individuals in our country.
Similar studies have not been performed in other countries of the Caribbean region, and those carried out in the rest of the continent probably do not reflect their real situation. HIV-1 genetic diversity in our region has not been widely studied, which is why we could not say for certain that this result has no parallel in the Americas, let alone that it is comparable with results found in central Africa.
The introduction of recombinant forms into Cuba cannot be explained only by the presence of Cuban personnel in Africa, because the number of Cubans who were infected in that continent is low. As at December 2000, 178 cases of Cubans who had been infected in Africa had been registered, representing 5.25% of the 3230 HIV-seropositive individuals reported up to that date .
To consider the non-B HIV/AIDS Cuban patients to be a threat to tourists travelling to Cuba from western Europe is a mistake, taking into consideration the low prevalence of HIV infection among the Cuban population, and also as samples from prostitutes were not included in the study.
The Cuban authors involved in the investigation that originated the article agreed that there was no correspondence between the interpretation of the results and the epidemiological characteristics of the HIV/AIDS infection in Cuba. The findings of new subtypes and CRF in the sample are not representative of the HIV/AIDS Cuban population.
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