Archaeogenomic distinctiveness of the Isthmo-Colombian area.

The recently enriched genomic history of Indigenous groups in the Americas is still meager concerning continental Central America. Here, we report ten pre-Hispanic (plus two early colonial) genomes and 84 genome-wide profiles from seven groups presently living in Panama. Our analyses reveal that pre-Hispanic demographic events contributed to the extensive genetic structure currently seen in the area, which is also characterized by a distinctive Isthmo-Colombian Indigenous component. This component drives these populations on a specific variability axis and derives from the local admixture of different ancestries of northern North American origin(s). Two of these ancestries were differentially associated to Pleistocene Indigenous groups that also moved into South America, leaving heterogenous genetic footprints. An additional Pleistocene ancestry was brought by a still unsampled population of the Isthmus (UPopI) that remained restricted to the Isthmian area, expanded locally during the early Holocene, and left genomic traces up to the present day.

Detection of Leishmania RNA Virus 1 in Leishmania (Viannia) panamensis Isolates, Panama.

We detected Leishmania RNA virus 1 (LRV1) in 11 isolates of Leishmania (Viannia) panamensis collected during 2014-2019 from patients from different geographic areas in Panama. The distribution suggested a spread of LRV1 in L. (V.) panamensis parasites. We found no association between LRV1 and an increase in clinical pathology.

Real-time RT-PCR for Venezuelan equine encephalitis complex, Madariaga, and Eastern equine encephalitis viruses: application in human and mosquito public health surveillance in Panama.

Eastern equine encephalitis virus (EEEV), Madariaga virus (MADV), and Venezuelan equine encephalitis virus complex (VEEV) are New World alphaviruses transmitted by mosquitoes. They cause febrile and sometimes severe neurological diseases in human and equine hosts. Detecting them during the acute phase is hindered by non-specific symptoms and limited diagnostic tools. We designed and clinically assessed real-time reverse transcription polymerase chain reaction assays (rRT-PCRs) for VEEV complex, MADV, and EEEV using whole-genome sequences. Validation involved 15 retrospective serum samples from 2015 to 2017 outbreaks, 150 mosquito pools from 2015, and 118 prospective samples from 2021 to 2022 surveillance in Panama. The rRT-PCRs detected VEEV complex RNA in 10 samples (66.7%) from outbreaks, with one having both VEEV complex and MADV RNAs. VEEV complex RNA was found in five suspected dengue cases from disease surveillance. The rRT-PCR assays identified VEEV complex RNA in three Culex (Melanoconion) vomerifer pools, leading to VEEV isolates in two. Phylogenetic analysis revealed the VEEV ID subtype in positive samples. Notably, 11.9% of dengue-like disease patients showed VEEV infections. Together, our rRT-PCR validation in human and mosquito samples suggests that this method can be incorporated into mosquito and human encephalitic alphavirus surveillance programs in endemic regions.

Detection of parechovirus A in respiratory, gastrointestinal, and neurological clinical samples of pediatric patients from Panama (2014-2015).

Parechovirus A (PeV-A, Parechovirus, Picornaviridae) are human pathogens associated with mild to severe gastrointestinal and respiratory diseases in young children. While several studies have investigated the association of PeV-A with human disease, little is known about its epidemiology or detection in Latin America. Between the years 2014 and 2015, a total of 200 samples were collected from Panamanian pediatric patients aged < 16 years old exhibiting symptoms associated with respiratory (n = 64), gastrointestinal (n = 68), or neurological (n = 68) diseases. These samples were gathered from patients who had previously received negative diagnoses for the main respiratory viruses, rotavirus, and neurological viruses like herpes virus, enterovirus, and cytomegalovirus. The presence of PeV-A was analyzed by real time RT-PCR.Eight positive PeV-A infections (4.0%, 95% CI: 1.7 to 7.7) were detected: two in respiratory samples (3.0%, 95% CI: 0.3 to 10.8), five in gastrointestinal samples (7.3%, 95% CI: 2.4 to 16.3), and one in cerebrospinal fluid (1.5%, 95% CI: 1.4 to 7.9). The study provides evidence of PeV-A circulation in Panama and the data collectively, remarked on the importance of considering PeV-A in the Panamanian pediatric diagnostic landscape, especially when conventional testing for more common viruses yields negative results.

How did COVID-19 measures impact sexual behaviour and access to HIV/STI services in Panama? Results from a national cross-sectional online survey.

OBJECTIVE: To describe reported changes in sexual behaviours, including virtual sex (sexting and cybersex), and access to HIV/STI testing and care during COVID-19 measures in Panama. METHODS: We conducted an online cross-sectional survey from 8 August to 12 September 2020 among adults (≥18 years) residing in Panama. Participants were recruited through social media. Questions included demographics, access to HIV/STI testing and HIV care, and sexual behaviours 3 months before COVID-19 social distancing measures and during social distancing measures (COVID-19 measures). Logistic regression was used to identify associations between variables and behavioural changes. RESULTS: We recruited 960 participants; 526 (54.8%) identified as cis-women, 366 (38.1%) cis-men and 68 (7.1%) non-binary or another gender. The median age was 28 years (IQR: 23-37 years), and 531 of 957 (55.5%) were of mixed ethnicity (mixed Indigenous/European/Afro-descendant ancestry). Before COVID-19 measures, virtual sex was reported by 38.5% (181 of 470) of cis-women, 58.4% (184 of 315) cis-men and 45.0% (27 of 60) non-binary participants. During COVID-19 measures, virtual sex increased among 17.2% of cis-women, 24.7% cis-men and 8.9% non-binary participants. During COVID-19 measures, 230 of 800 (28.8%) participants reported decreased casual sex compared with pre-COVID-19 measures. Compared with pre-COVID-19 measures, decreased casual sex was reported more frequently during COVID-19 measures by cis-men compared with cis-women (39.2% vs 22.9%, urban/rural adjusted OR (AOR)=2.17, 95% CI 1.57 to 3.01), and by Afro-descendant compared with participants of mixed ethnicity (40.0% vs 29.8%, AOR=1.78, 95% CI 1.07 to 2.94). Compared with no change in virtual sex (16.8%), increased virtual sex (38.5%, AOR=1.78, 95% CI 1.10 to 2.88) and decreased virtual sex (86.7%, AOR=16.53, 95% CI 7.74 to 35.27) were associated with decreased casual sex encounters. During COVID-19 measures, HIV/STI testing could not be obtained by 58.0% (58 of 100) of the participants who needed a test, and interrupted HIV care was reported by 53.3% (8 of 15) of participants living with HIV. CONCLUSIONS: COVID-19 measures in Panama were associated with a decrease in casual sex among cis-men and Afro-descendant people, while access to HIV/STI testing and care was seriously disrupted.

Early Transmission Dynamics, Spread, and Genomic Characterization of SARS-CoV-2 in Panama.

We report an epidemiologic analysis of 4,210 cases of infection with severe acute respiratory syndrome coronavirus 2 and genetic analysis of 313 new near-complete virus genomes in Panama during March 9-April 16, 2020. Although containment measures reduced R0 and Rt, they did not interrupt virus spread in the country.

Prevalence and determinants of genital Chlamydia trachomatis among school-going, sexually experienced adolescents in urban and rural Indigenous regions of Panama.

OBJECTIVES: To determine the prevalence and risk factors of genital Chlamydia trachomatis (CT) among school-going sexually experienced male and female adolescents in Panama. METHODS: We conducted two multisite cross-sectional studies using two-stage cluster sampling to select adolescents aged 14-19 years attending urban public high schools (URB) in Panama City, San Miguelito, Colón and Panama Oeste from 2015 to 2018, and in the rural Indigenous Comarca Ngäbe-Buglé (CNB) from July-November 2018. CT testing was performed by real-time PCR on urine samples. Random-effects logistic regression accounting for sample clustering was used to identify risk factors. RESULTS: We enrolled 3166 participants (54.3% females), median age 17 years (IQR: 15.9-18.1), with no difference by sex. Sexual experience was reported by 1954 (61.7%) participants. Combined CT prevalence was 15.8% (95% CI: 14.2 to 17.4), with no significant differences by region (URB=16.5%, 95% CI: 14.7% to 18.6%; CNB=13.6%, 95% CI: 10.9% to 16.8%; p=0.12). In an age-and-region-adjusted analysis, CT prevalence was higher among female participants compared with males (21.6% vs 9.1%, adjusted OR (AOR)=2.87, 95% CI: 1.62 to 5.10). Among sexually experienced females, CT prevalence was higher among those who reported ≥3 lifetime sex partners compared with one partner (33.5% vs 15.3%, AOR=2.20, 95% CI: 1.09 to 4.07); and among those reporting at least one pregnancy compared with nulligravidae participants (30.9% vs 13.8%, AOR=1.89, 95% CI: 1.05 to 3.43). In unadjusted analyses among males, CT was associated with older age (11.5% among those aged 18-19 years vs 3.4% among those aged 14-15 years, OR=3.69, 95% CI: 1.10 to 12.33). CONCLUSIONS: We report high CT prevalence among sexually experienced, school-going adolescents in Panama. Female adolescents, particularly those with multiple sex partners and a history of pregnancy, were at highest risk. Adolescent-targeted CT screening should be implemented in Panama. Additionally, evidence-based comprehensive sexuality education will be imperative.

Gender norms and sexual behaviours among Indigenous youth of the Comarca Ngäbe-Buglé, Panama.

The Comarca Ngäbe-Buglé, an administratively autonomous Indigenous region in western Panama, is home to a significant population rural Indigenous people of Ngäbe and Buglé ethnicity. HIV prevalence in the Comarca is two times higher than the national average, and the great majority of cases are concentrated in young men. Yet, there is little data regarding socio-cultural and sexual behaviour factors that may drive this high prevalence. Understanding such factors would enable the development of relevant prevention interventions. We conducted a qualitative study between January and March 2018, consisting of 20 semi-structured interviews with male and female young people aged 14-19 years, complemented with ethnographic observations of one month's duration each in two communities within the Comarca, to identify potential factors that could increase risk of HIV and other sexually transmitted infections (STIs). We suggest that interventions to prevent HIV and other STIs should focus on increasing open communication between sex partners, especially with respect to condom use, as well as facilitating people-driven change in gender norms that are harmful to both young women and young men.

High Prevalence of Sexually Transmitted Infections, and High-Risk Sexual Behaviors Among Indigenous Adolescents of the Comarca Ngäbe-Buglé, Panama.

BACKGROUND: There is scant information on sexually transmitted infection (STI) prevalence and risk factors among Latin American indigenous populations. We investigated STI prevalence and risk factors among adolescents of the Comarca Ngäbe-Buglé indigenous region of Panama. METHODS: A population-based cross-sectional study was conducted among school-going adolescents aged 14 to 19 years. Eligible consenting participants self-completed a questionnaire and provided blood and urine samples. Female participants provided additional self-administered genital swabs. Seroprevalences of human immunodeficiency virus (HIV), syphilis, hepatitis B (HBsAg, anti-HBc), and herpes simplex virus type 2 (HSV-2) were determined in all participants; genital Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) by PCR among participants who reported sexual experience or were seropositive for HIV/syphilis/HSV2/HBsAg; high-risk human papillomavirus (HPV) by qualitative DNA assay and bacterial vaginosis (BV) by Gram-stain among female participants. Risk factors were identified by estimating adjusted odds ratios (AOR) using random-effects logistic regression. RESULTS: We enrolled 700 participants (median age, 17 years [female participants]; 18 years [male participants]) from 20 schools. Sexual experience was reported by 536 participants (76.6%). The HIV/STI prevalences among females and males were: HIV 0.4% and 1.0%, high-titer active syphilis 1.3% and 6.6%, HSV-2 16.1% and 16.1%, HBsAg 1.3% and 1.4%, anti-HBc 3.2% and 1.4%, NG 1.8% and 1.7%, CT 17.5% and 10.7%; among females: BV 42.9% and HPV 33.2%. CT was independently associated with being female (AOR, 2.02; 95% confidence interval [CI], 1.20-3.41); high-titer active syphilis with being male (AOR, 4.51; 95% CI, 1.17-17.40). Bacterial vaginosis was associated with sexual behavior (≥3 lifetime sex partners: AOR, 3.81; 95% CI, 1.29-11.26), HPV with sexual experience (AOR, 4.05; 95% CI, 1.62-10.09). CONCLUSIONS: School-going indigenous adolescents in rural Panama have substantial STI burden. Targeted STI screening is required.

Genotypes of human metapneumovirus circulating during 2010-2012 in children from Panama.

Human metapneumovirus (HMPV) is a common causative agent of severe respiratory tract infections in children under 5 years old, the elderly and immunocompromised patients, being responsible for 5-15% of all viral respiratory infections requiring hospitalization. Though HMPV was included in the surveillance program for respiratory viruses in 2010, its genotype distribution remains unknown. Herein, 45 positive samples to HMPV from children ≤5 years old were characterized by phylogenetic analysis based on N gene sequence. Results showed the co-circulation of four sub-lineages: A2a (8.8%), A2b (55.5%), B1 (15.6%), and B2 (20%), demonstrating the genetic heterogeneity of HMPV circulating in Panamá.

Clinical Manifestations of Punta Toro Virus Species Complex Infections, Panama, 2009.

An investigation in Panama found that Punta Toro virus species complex (PTVs) may contribute to febrile illnesses with symptoms mirroring those of dengue fever. However, further studies are needed to determine if PTV infection causes only a mild disease or if it can have more serious manifestations in some patients.

Genetic variability of human respiratory syncytial virus group B in Panama reveals a novel genotype BA14.

In Panama, human respiratory syncytial virus (HRSV) is responsible of 20-40% of acute respiratory infections in children under 5 years old. Currently, little is known about the genetic variability of HRSV in Central America and the Caribbean. Recently, we reported the genetic variability of HRSV-A, however; no studies on HRSV-B in Panama have been described yet. In this study, 24 sequences of Panamanian HRSV-B, from children (<5 years) with acute respiratory infections (ARI), collected from July 2008 to November 2012 were analyzed. All sequences share the characteristic 60-nt duplication of the BA strains. Six Panamanian strains grouped with the BA10 genotype and 12 samples clustered together in a separate monophyletic clade with an aLRT support value of 0.92 and an intra-group p-distance less than 0.07. This fulfills the criteria to consider a new genotype in HRSV, which we named BA14 genotype. Another six strains remain unclassified, but closely related to BA9, BA11, or the new BA14 genotypes, according to their genetic p-distance. Different amino acid substitutions in the Panamanian HRSV-B strains were observed, some previously described and others found only on Panamanian strains. This study contributes to the knowledge of the genetic variability and evolution of HRSV in Central America.

Conservation of G-Protein Epitopes in Respiratory Syncytial Virus (Group A) Despite Broad Genetic Diversity: Is Antibody Selection Involved in Virus Evolution?

UNLABELLED: Worldwide G-glycoprotein phylogeny of human respiratory syncytial virus (hRSV) group A sequences revealed diversification in major clades and genotypes over more than 50 years of recorded history. Multiple genotypes cocirculated during prolonged periods of time, but recent dominance of the GA2 genotype was noticed in several studies, and it is highlighted here with sequences from viruses circulating recently in Spain and Panama. Reactivity of group A viruses with monoclonal antibodies (MAbs) that recognize strain-variable epitopes of the G glycoprotein failed to correlate genotype diversification with antibody reactivity. Additionally, no clear correlation was found between changes in strain-variable epitopes and predicted sites of positive selection, despite both traits being associated with the C-terminal third of the G glycoprotein. Hence, our data do not lend support to the proposed antibody-driven selection of variants as a major determinant of hRSV evolution. Other alternative mechanisms are considered to account for the high degree of hRSV G-protein variability. IMPORTANCE: An unusual characteristic of the G glycoprotein of human respiratory syncytial virus (hRSV) is the accumulation of nonsynonymous (N) changes at higher rates than synonymous (S) changes, reaching dN/dS values at certain sites predictive of positive selection. Since these sites cluster preferentially in the C-terminal third of the G protein, like certain epitopes recognized by murine antibodies, it was proposed that immune (antibody) selection might be driving the apparent positive selection, analogous to the antigenic drift observed in the influenza virus hemagglutinin (HA). However, careful antigenic and genetic comparison of the G glycoprotein does not provide evidence of antigenic drift in the G molecule, in agreement with recently published data which did not indicate antigenic drift in the G protein with human sera. Alternative explanations to the immune-driven selection hypothesis are offered to account for the high level of G-protein genetic diversity highlighted in this study.

Detection of human bocavirus type 1 infection in Panamanian children with respiratory illness.

The human bocavirus (HBoV) was added as a new member of the Parvoviridae family in 2005 upon its discovery in nasopharyngeal aspirates from children with respiratory infection. Recently, there has been increasing evidence of worldwide circulation of HBoV; however, in Latin America few studies have been conducted. In order to detect the circulation of HBoV in Panama, based on the National Flu Surveillance System, we developed this retrospective, cross-sectional study, from January 2011 to January 2012. Children younger than 6 years old who presented with respiratory disease were enrolled in this study. Nasopharyngeal swabs were taken in sentinel surveillance sites. Samples were tested to detect mRNA from HBoV, as well as viral RNA and DNA from others respiratory viruses. A total of 1078 patients were enrolled in this study. Overall, 44 (4.1%) of the patients presented HBoV. The most common symptoms were cough (84.6%), fever (82.1%), rhinorrhea (74.4%), and sore throat (38.5%). Less than half (45.5%) of HBoV infected patients presented with monoinfection while 54.5% of cases presented with coinfection with others respiratory viruses. Both, outpatients and inpatients were included in this study. Outpatients corresponded to 52.3% of the cases and 47.7% were inpatients. Coinfection was observed in the 50% of the inpatient cases. Phylogenetic analyses indicated that the circulating strains belonged to different clades of HBoV genotype 1. Taken together, our results support the pathogenic nature of this viral agent, especially in younger children.

Prevalence of HIV, syphilis, and other sexually transmitted infections among MSM from three cities in Panama.

Respondent-driven sampling (RDS) was used to conduct a biobehavioral survey among men who have sex with men (MSM) in three cities in the Republic of Panama. We estimated the prevalence of HIV, syphilis, and other sexually transmitted infections (STIs), sociodemographic characteristics, and sexual risk behaviors. Among 603 MSM recruited, RDS-adjusted seroprevalences (95 % confidence intervals) were: HIV-David 6.6 % (2.2-11.4 %), Panama 29.4 % (19.7-39.7 %), and Colon 32.6 % (18.0-47.8 %); active syphilis-David 16.0 % (8.9-24.2 %), Panama 24.7 % (16.7-32.9 %), Colon 31.6 % (14.8-47.5 %); resolved HBV infection-David 10.0 % (4.8-16.8 %), Panama 29.4 % (20.0-38.3 %), and Colon 40.6 % (21.9-54.4 %); herpes simplex virus type 2-David 38.4 % (27.9-48.9 %), Panama 62.6 % (52.8-71.0 %), and Colon 72.9 % (57.4-85.8 %). At least a third of MSM in each city self-identified as heterosexual or bisexual. HIV prevalence is concentrated among MSM. Preventive interventions should focus on increasing HIV and syphilis testing, and increasing promotion of condom awareness and use.

Social norms that sustain transactional sex and associations with sexual health outcomes: A mixed-methods study in the Comarca Ngäbe-Buglé, a rural-Indigenous region of Panama.

The Comarca Ngäbe-Buglé (CNB), home to >200,000 Indigenous people, is one of the poorest regions in Panama. We describe transactional sex (TS) behaviours, normative beliefs and factors associated with TS among Indigenous adolescents(14-19years) in the CNB. We conducted a mixed-methods study in the CNB between January and November 2018, which included a qualitative study with participant observation and semi-structured interviews that focused on descriptive norms related to TS; and a cross-sectional study among public-school-going adolescents using self-administered questionnaire to report sexual behaviour and injunctive norms related to TS. Participants in the epidemiological study were also asked to submit samples for HIV, syphilis, chlamydia, and gonorrhoea testing. Qualitative thematic analysis was used to organise and analyse field notes and semi-structured interviews. Quantitative analysis included four models: TS experience and acceptance of a TS offer and the associations of these outcome variables with demographic and behavioural variables and HIV/STI infections. In the qualitative study among 20 adolescents, we found that people offering TS were reported to be from within and outside of the community, and included older men and women, and disturbingly, teachers. Participants reported feeling individual and collective agency in the decision to engage in TS and described little social sanctions for participation. In the quantitative study among 700 adolescents(309 girls[45.1%],379 boys[54.9%]), we found that girls(18.8%;58/309) and boys(15.5%;58/379) reported similar levels of having been offered TS, and of acceptance among those offered(girls 81.4% [35/43]; boys 77.8% [35/45]). TS was found to be associated with the reported forced sex and HIV/syphilis seropositivity. Due to widespread acceptance and feelings of agency, interventions would not be effective if they focused on eliminating the transactional component of sexual encounters. Instead, interventions should focus on individual and household economic stability, increasing violence reporting, bringing perpetrators to justice, and adopting condom use during all sexual encounters.

Prevalence of syphilis among people living with HIV who attend a large urban antiretroviral therapy clinic in Panama: a cross-sectional epidemiological study.

Background: Syphilis is a serious global public health challenge. Despite prior progress in syphilis control, incidence has been increasing in recent years. Syphilis is a common coinfection among people living with HIV (PLHIV). In Panama, few data describe syphilis prevalence among PLHIV. We describe syphilis antibody and high-titer (⩾1:8) active syphilis prevalence and associated factors among individuals who attended an antiretroviral clinic. Methods: A cross-sectional study was undertaken during February-March 2022 and September-October 2022 for adults (⩾18 year) assigned male and female at birth, respectively. Participants provided peripheral blood samples and self-administered a questionnaire. Samples were screened using immunochromatography; antibody-positive samples were tested using rapid plasma regain to 1:512 dilutions. Logistic regression was used to identify factors associated with syphilis antibody and high-titer active syphilis. Results: In all, 378 participants gave blood samples; 377 individuals participated in the questionnaire (216 self-reported male sex [males], 158 female [females], and three intersex individuals). Median age was 36 years (interquartile range: 28-45 years). Overall, syphilis antibody prevalence was 32.3% (122/378) (males, 50.7% [108/2013]; females, 5.7% [9/158]; intersex individuals, 100.0% (3/3)], p < 0.01. High-titer active syphilis was found among 24.6% (n = 30) of samples with positive antibody test (males 27.8% [n = 30], females 0.0% [0/9], intersex individuals 0.0% [0/3]). Antibody positivity was associated in the multivariable model with males (50.7%, AOR = 24.6, 95%CI: 1.57-384.53). High-titer active syphilis was associated with younger participant age (18-30 years, 13.2%, OR = 4.82, 95%CI: 1.17-19.83); 31-40 years, 7.8%, OR = 4.24, 95%CI: 1.04-17.21 versus 3.2% >40 years), homosexual identity (16.0% OR = 34.2, 95%CI: 4.50-259.27 versus 0.6% among heterosexual identity); in the multivariable model, associated with sexual identity (bisexual 19.1%, AOR = 10.89, 95%CI: 1.00-119.06) compared to heterosexual identity (0.6%) and weakly associated with concurrency (⩾1 ongoing sexual relationships, 15.9%, AOR = 3.09, 95%CI: 0.94-10.14). Conclusion: This study found very high prevalence of syphilis antibodies and high-titer syphilis among PLHIV in Panama. Those most affected are males, younger in age, those who practice concurrent sexual relationships, and those who reported homosexual and bisexual identity. Targeted interventions should include repetitive testing and treatment, especially among individuals who may be at increased infection risk.

Prevalence of syphilis among people living with HIV who attend a large antiretroviral therapy clinic, Panama, 2022 Syphilis is a significant health challenge worldwide. On a global scale, yearly syphilis incidence is increasing, including in Panama. However, there are no current data to explain syphilis prevalence and who is most affected among people living with HIV in Panama. In order to understand syphilis in Panama and create targeted interventions among specific groups of people, it is important to describe how many people are infected, and who is most affected by this infection. Therefore, we conducted a study among 378 people living with HIV at a treatment clinic in Panama City, Panama. Blood samples and demographic data were collected. In all, syphilis antibodies were found in 32.3% of individuals (50.7% of those who self-report as males, 5.7% as females, and 100% of those who self-report as intersex. Of those with positive antibody tests, 24.6% of individuals also had active syphilis. Only individuals who identify as male had active syphilis. Our findings show high syphilis prevalence among people with HIV in Panama City, particularly among males, those who are younger, those who report sexual identity as homosexual or bisexual, and those with ongoing sexual relationships with more than one individual. Targeted interventions are needed among people living with HIV, especially among the groups most affected. These interventions could include testing more often for syphilis and providing timely treatment, especially among individuals who may be at increased risk of infection.

Prevalence of HIV and other sexually transmitted infections and factors associated with syphilis among female sex workers in Panama.

OBJECTIVES: Biological and behavioural surveillance of HIV and sexually transmitted infections (STIs) among populations at highest risk have been used to monitor trends in prevalence and in risk behaviours. Sex work in Panama is regulated through registration with the Social Hygiene Programme, Ministry of Health. We estimated prevalence of HIV and STIs, and factors associated with active syphilis among female sex workers (FSWs). METHODS: A cross-sectional study using venue-based, time-space sampling was conducted among FSWs in Panama from 2009 to 2010. FSWs were interviewed about sociodemographic characteristics, sexual risk behaviour, health history and drug use using an anonymous structured questionnaire. Blood was collected for serological testing of HIV and other STIs. Factors associated with active syphilis were studied using logistic regression analysis. RESULTS: The overall HIV-1 prevalence of 0.7% varied by FSW category; 1.6% in 379 unregistered, and 0.2% in 620 registered FSWs. Overall prevalence (and 95% CI) of STIs were: syphilis antibody, 3.8% (2.7% to 5.2%); herpes simplex virus type 2 antibody (anti-HSV-2), 74.2% (71.4% to 76.9%); hepatitis B surface antigen, 0.6% (0.2% to 1.3%); hepatitis B core antibody, 8.7% (7.0% to 10.6%); and hepatitis C antibody, 0.2% (0.0% to 0.7%). In multivariate analysis, registration (adjusted OR (AOR)=0.35; 95% CI 0.16 to 0.74), having a history of STI (AOR=2.37; 95% CI 1.01 to 5.58), forced sex (AOR=2.47; 95% CI 1.11 to 5.48), and anti-HSV-2 (AOR=10.05; 95% CI 1.36 to 74.38) were associated with active syphilis. CONCLUSIONS: Although HIV prevalence is low among FSWs in Panama, unregistered FSWs bear a higher burden of HIV and STIs than registered FSWs. Programmes aimed at overcoming obstacles to registration, and HIV, STI and harm reduction among unregistered FSWs is warranted to prevent HIV transmission, and to improve their sexual and reproductive health.

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.

A method for mapping the linear epitopes targeted by the natural antibody response to Zika virus infection using a VLP platform technology.

Zika virus (ZIKV), a mosquito-borne pathogen, is associated with neurological complications in adults and congenital abnormalities in newborns. There are no vaccines or treatments for ZIKV infection. Understanding the specificity of natural antibody responses to ZIKV could help inform vaccine efforts. Here, we used a technology called Deep Sequence-Coupled Biopanning to map the targets of the human antibody responses to ZIKV infection. A bacteriophage virus-like particle (VLP) library displaying overlapping linear peptides derived from the ZIKV polyprotein was generated. The library was panned using IgG from 23 ZIKV-infected patients from Panama and deep sequencing identified common targets of anti-ZIKV antibodies within the ZIKV envelope glycoprotein. These included epitopes within the fusion loop within domain II and four epitopes within domain III. Additionally, we showed that VLPs displaying selected epitopes elicited antibodies that bound to native ZIKV envelope protein but failed to prevent infection in a mouse challenge model.