Prevalence of Human Papillomavirus in Women from the State of Michoacan, Mexico, Showed High Frequency of Unusual Virus Genotypes

Abstract

Background: Human papillomaviruses (HPVs), the leading cause of cervical cancer, are distributed worldwide, with high prevalence in developing countries.

Objective: The objective of the study is to know the prevalence and genotypes of HPV in women from the state of Michoacán and the Women's Hospital in Morelia, Michoacán.

Materials and methods: Cervical smear samples (159,288) were subjected to HPV detection by hybrid capture 2. A subsample of 484 patients from the Women's Hospital was studied by Papanicolaou test and linear array HPV genotyping, and when positive, patients were also examined by colposcopy and histopathology.

Results: The overall prevalence for HPV in Michoacán State was 7.74%; 7.11% in 2009, 6.46% in 2010, 9.58% in 2011, and 8.43% in 2012. The highest prevalence was found in the age groups < 25 and 25-34 years. The prevalence at the Women's Hospital was 8.51%. Cytological examination revealed normal cytology in 64.44% of samples, 26.66 % with low-grade and 8.88 % with high-grade squamous intraepithelial lesion (HSIL). However, by colposcopy, normal tissue appearance was found only in 26.66%; 51% were reclassified as low-grade squamous intraepithelial lesion, 17.77% as HSIL, and in 4.4% atrophy was observed. The most prevalent genotype in single infections was HPV59, followed by HPV51 and HPV45. Double infections occurred with the following genotypes: 52-53, 51-59, 61-67, 66-11, 16-62, 53-62, 59-CP6108, 45-66, and 45-51. Triple infections were identified as: 6-31-39, 51-59-62, 51-62-81, 54-55-59, 16-58-71, and 16-59-62.

Conclusions: The prevalent genotype found among women from Michoacán, HPV59, was different to the rest of the country. The high prevalence of HPV59 could be due to cases imported to Michoacán by agricultural workers migrating to the USA or may be associated to ethnicity differences. Implications of this finding for immunization programs should be explored.