High Diversity of Hepatitis B Virus Genotypes in Panamanian Blood Donors: A Molecular Analysis of New Variants

<div><p>Hepatitis B Virus (HBV) is an infectious agent that causes more than half of the cases of liver disease and cancer in the world. Globally there are around 250 million people chronically infected with this virus. Despite 16% of the cases of liver disease in Central America are caused by HBV, the information regarding its genetic diversity, genotypes and circulation is scarce. The purpose of this study was to evaluate the genetic variability of the HBV genotypes from HBV-DNA positive samples obtained from screening blood donors at the Social Security System of Panama and to estimate its possible origin. From 59,696 blood donors tested for HBV infection during 2010–2012, there were 74 HBV-DNA positive subjects. Analysis of the partial PreS2-S region of 27 sequences shows that 21% of the infections were caused by genotype A, 3% by genotype D and 76% by genotype F. In addition, we were able to confirm circulation of six sub-genotypes A1, A2, A3, D4, F3, F1 and a proposed new sub-genotype denominated F5pan. We found a confinement of sub-genotypes F1 and F5pan to the western area of Panama. The tMRCA analysis suggests a simultaneous circulation of previously described sub-genotypes rather than recent introductions of the Panamanian sub-genotypes in the country. Moreover, these results highlight the need of more intensive research of the HBV strains circulating in the region at the molecular level. In conclusion, Panama has a high HBV genotype diversity that includes a new proposed sub-genotype, an elevated number of PreCore-Core mutations, and confinement of these variants in a specific geographical location.</p></div

Rickettsial infection in domestic mammals and their ectoparasites in El Valle de Anton, Cocle, Panama

The present research evaluated the presence of Rickettsia spp. on ectoparasites of horses and dogs (using PCR techniques), and their sera (using immunofluorescence assay) in El Valle de Anton town in Panama. A total of 20 horses and 20 dogs were sampled, finding four species of ectoparasites on dogs (the ticks Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma oblongoguttatum, and the flea Ctenocephalides felis), and two tick species on horses (Amblyomma cajennense and Dermacentor nitens). DNA of Rickettsia amblyommii was found in pools of A. cajennense, D. nitens, and R. sanguineus, while Rickettsia fells was detected in C. felis pools. Overall, 70% (14/20) and 65% (13/20) of the horses and dogs, respectively, were seroreactive (titer >= 64) to spotted fever group rickettsiae. Sera from six dogs and five horses reacted to R. amblyommii antigens with titers at least four-fold higher than those for the other antigens tested (Rickettsia bellii, Rickettsia parked, Rickettsia rhipicephali, R. felis, and R. rickettsii). These serological results, coupled with our molecular findings, suggest that these dogs and horses were infected by Rickettsia amblyommii. More studies need to be realized afford to identify the Rickettsia species responsible for other serological and molecular positive results, and their ecological importance. (C) 2010 Elsevier B.V. All rights reserved.Secretaria Nacional de Ciencia y Tecnologia (SENACYT-Panama)[COL 007-45]Autoridad Nacional del Ambiente (ANAM

Molecular characterisation of hepatitis B virus in the resident Chinese population in Panama City

Despite the effectiveness of current hepatitis B virus (HBV) vaccines, it is estimated that 350 million individuals suffer from chronic HBV infection and more than 50% of these affected individuals live on the Asian continent. Panama is a country with a great diversity of foreign groups; the Chinese community is a large example of this phenomenon. There is an urgent need to perform studies that evaluate the prevalence and the genetic diversity of HBV in this community. This study aimed to evaluate the prevalence of HBV and its genotypes and mutant variants in the Chinese population residing in Panama. In total, 320 subjects were enrolled in the study. Forty-two subjects (13.1%) were positive for HBsAg and HBV-DNA from 18 subjects revealed the presence of genotypes B2 and C1. Secondary mutations associated with drug resistance at positions rtV207L and rtN239T of the reverse transcriptase gene were identified. Additionally, the mutation pair A1762T/G1764A was found in three samples and the mutation G1896A was detected in an HBeAg-negative subject. In conclusion, to our knowledge, this is the first study to report high HBV prevalence rates in resident ethnic Chinese in Central America and the presence of genotypes B2 and C1 in this region

Mean percentage nucleotide divergences among the whole genome of HBV sub-genotype F.

<p>Mean ± standard deviations from averaging over all sequence pairs between groups are shown. Sub-subgenotype F5 values are displayed in bold, genotype H is added as a reference. Analyses were conducted using p-distances as implemented in MEGA5 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103545#pone.0103545-Tamura1" target="_blank">[21]</a>.</p

Whole genome Maximum likelihood tree constructed with HBV Genotype F sub-genotype reference sequences (F1–F4).

<p>(a), PreS2-S gene (b) and Core gene (c) (n = 75) and sequences of Panamanian origin (bold circle). Support αLTR and bootstrap values (αLTR/bootstrap) higher than 0.75 are shown, HBV genotype H is used as out-group. The length of the horizontal bars indicates the number of nucleotide substitutions per site.</p

Time resolved phylogenetic tree showing the relationships among the whole genome sequences of Panamanian samples and sub-genotypes F of diverse origin.

<p>The date of MRCA is shown in the node of relevant sub-genotypes and nodes formed by Panamanian samples. Bayesian posterior probabilities (>0.75) of each clade is shown above the relevant branch.</p

Midpoint rooted Maximum Likelihood tree based on HBV partial PreS2-S reference sequences of each genotype (A–I) (n = 280) and sequences of Panamanian origin.

<p>(∼820 pb, n = 27, bold circle). Clades in which there are not Panamanian samples are collapsed to simplify, node numbers correspond to αLTR values higher than 0.50.</p

Map of Panama indicating the origin of the HBV sequences analyzed in this study.

<p>The top left pie chart indicates the number of sequences according to the genotype, the middle bar plot indicates the number of genotypes according to geographic area. The pie charts within the map indicated the proportion of the sub-genotype found in the corresponding region.</p

Estimated of tMRCA for Genotype F, with Whole genome, polymerase and PreC-Core fragments of Panamanian samples.

<p>tMRCA calculated by calibration with a fixed substitution mean rate (1.5 E-5) and time-stamped data under the best-fit demographic model indicated by the log-marginal likelihood analysis (appendix, S3). The Bayesian analysis was performed for the HBV whole genome, and a portion (876 pb) of polymerase gene from the available sequences (databases available upon request). The years correspond to dates in the past.</p><p>*substitutions/site/year.</p