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Abstract Background Dengue (DEN) is an infectious disease caused by the DEN virus (DENV), which belongs to the Flavivirus genus in the family Flaviviridae. It has a (+) sense RNA genome and is mainly transmitted to humans by the vector mosquito Aedes aegypti. Dengue fever (DF) and dengue hemorrhagic fever (DHF) are caused by one of four closely related virus serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). Epidemiological and evolutionary studies have indicated that host and viral factors are involved in determining disease outcome and have proved the importance of viral genotype in causing severe epidemics. Host immune status and mosquito vectorial capacity are also important influences on the severity of infection. Therefore, an understanding of the relationship between virus variants with altered amino acids and high pathogenicity will provide more information on the molecular epidemiology of DEN. Accordingly, knowledge of the DENV serotypes and genotypes circulating in the latest DEN outbreaks around the world, including Mexico, will contribute to understanding DEN infections. Results 1. We obtained 88 isolates of DENV, 27 from Oaxaca and 61 from Veracruz. 2. Of these 88 isolates, 16 were serotype 1; 62 serotype 2; 7 serotype 3; and 2 serotype 4. One isolate had 2 serotypes (DENV-2 and -1). 3. Partial nucleotide sequences of the genes encoding C- prM (14 sequences), the NS3 helicase domain (7 sequences), the NS5 S-adenosyl methionine transferase domain (7 sequences) and the RNA-dependent RNA polymerase (RdRp) domain (18 sequences) were obtained. Phylogenetic analysis showed that DENV-2 isolates belonged to the Asian/American genotype. In addition, the Asian/American genotype was divided into two clusters, one containing the isolates from 2001 and the other the isolates from 2005–2006 with high bootstrap support of 94%. Conclusion DENV-2 was the predominant serotype in the DF and DHF outbreak from 2005 to 2006 in Oaxaca State as well as in the 2006 outbreak in Veracruz State, with the Asian/American genotype prevalent in both states. Interestingly, DENV-1 and DENV-2 were the only serotypes related to DHF cases. In contrast, DENV-3 and DENV-4 were poorly represented according to epidemiological data reported in Mexico. We found that isoleucine was replaced by valine at residue 106 of protein C in the isolates from these 2005–2006 outbreaks and in those from the 1997, 1998 and 2001 outbreaks in the Caribbean islands. We suggested that this amino acid change may be used as a signature for isolates arising in the Caribbean islands and pertaining to the Asian/American genotype. Other amino acid changes are specific for the Asian/American, Asian and American strains.

Objectives: The functional variant R620W of the protein tyrosine phosphatase non receptor-22 (PTPN22) gene plays an important role in susceptibility to several immuno-mediated pathologies. Behçet's disease (BD) is a complex disease related to the immune system with a demonstrated genetic base. The HLA class I genes are the most important genetic factors in BD although other genes are also involved in the susceptibility to this disease. The PTPN22 has been proposed as a candidate gene in BD but this association has not been clearly demonstrated yet. The aim of this study was to assess the association of PTPN22 with BD., Methods: A cohort composed of 404 Spanish BD patients and 1517 unrelated healthy individuals ethnically matched was genotyped in rs2476601 (R620W). Five tag SNPs: rs1217412, rs2476599, rs3789607, rs3765598 and rs1217419 (spanning a 57 Kb region between 3'UTR and 5'UTR) and rs2488457 (located at the promoter region) were also studied in order to perform a screening of the complete gene. Genotyping was performed using TaqMan® assays. The rs2476601 data were included in a meta-analysis together with those published till the date. The rest of SNPs were used in a case-control study., Results: No evidence of the association of rs2476601 with BD in the meta-analysis (P = 0.504 in the model of alleles) was found. In the case-control study, no statistically significant differences were observed when comparing the distribution of variants in patients and controls., Conclusions: Our results do not support a major role of the PTPN22 gene in BD.