High-frequency trading and networked markets.

Financial markets have undergone a deep reorganization during the last 20 y. A mixture of technological innovation and regulatory constraints has promoted the diffusion of market fragmentation and high-frequency trading. The new stock market has changed the traditional ecology of market participants and market professionals, and financial markets have evolved into complex sociotechnical institutions characterized by a great heterogeneity in the time scales of market members' interactions that cover more than eight orders of magnitude. We analyze three different datasets for two highly studied market venues recorded in 2004 to 2006, 2010 to 2011, and 2018. Using methods of complex network theory, we show that transactions between specific couples of market members are systematically and persistently overexpressed or underexpressed. Contemporary stock markets are therefore networked markets where liquidity provision of market members has statistically detectable preferences or avoidances with respect to some market members over time with a degree of persistence that can cover several months. We show a sizable increase in both the number and persistence of networked relationships between market members in most recent years and how technological and regulatory innovations affect the networked nature of the markets. Our study also shows that the portfolio of strategic trading decisions of high-frequency traders has evolved over the years, adding to the liquidity provision other market activities that consume market liquidity.

Analysis of the Structure and Dynamics of European Flight Networks.

We analyze structure and dynamics of flight networks of 50 airlines active in the European airspace in 2017. Our analysis shows that the concentration of the degree of nodes of different flight networks of airlines is markedly heterogeneous among airlines reflecting heterogeneity of the airline business models. We obtain an unsupervised classification of airlines by performing a hierarchical clustering that uses a correlation coefficient computed between the average occurrence profiles of 4-motifs of airline networks as similarity measure. The hierarchical tree is highly informative with respect to properties of the different airlines (for example, the number of main hubs, airline participation to intercontinental flights, regional coverage, nature of commercial, cargo, leisure or rental airline). The 4-motif patterns are therefore distinctive of each airline and reflect information about the main determinants of different airlines. This information is different from what can be found looking at the overlap of directed links.

Allergic rhinits: impact on quality of life of adolescents.

SUMMARY: Adolescence is one of the most rapid phases of human development, in which biological maturity precedes psychosocial maturity. Rhinoconjunctivitis (ARC) is present in around 15 percent of 13-14-year-old children, which indicates a higher prevalence when compared with 6-7-year-old children (8.5 percent). During childhood (0-10 years) prevalence of Allergic Rhinitis (AR) is higher among males compared to females. Quite the reverse, during adolescence (11-17 years) females display higher prevalence of AR compared to males. However, when they reach adulthood (18-79 years), there is no difference in prevalence between genders. AR and ARC have significant physical and mental impacts on the QoL of adolescents and their parents. Apart from de adverse effects of first generation antihistamines, which include sedating effects, AR-ARC leads to school absences and poorer performance due to distraction, fatigue and irritability. The mobile technology facilitates an innovative investigatory approach to better and more precisely characterize allergy symptoms and their association with other allergic diseases. The success of treatment lies in the partnership between adolescents with AR and mobile technology, allowing them to have more information both on the disease and treatment. Adolescence is a special period in which AR is highly prevalent with some sex-dependent differences. There are also peculiarities on how AR affects QoL of adolescent patients.

PVAmpliconFinder: a workflow for the identification of human papillomaviruses from high-throughput amplicon sequencing.

BACKGROUND: The detection of known human papillomaviruses (PVs) from targeted wet-lab approaches has traditionally used PCR-based methods coupled with Sanger sequencing. With the introduction of next-generation sequencing (NGS), these approaches can be revisited to integrate the sequencing power of NGS. Although computational tools have been developed for metagenomic approaches to search for known or novel viruses in NGS data, no appropriate tool is available for the classification and identification of novel viral sequences from data produced by amplicon-based methods. RESULTS: We have developed PVAmpliconFinder, a data analysis workflow designed to rapidly identify and classify known and potentially new Papillomaviridae sequences from NGS amplicon sequencing with degenerate PV primers. Here, we describe the features of PVAmpliconFinder and its implementation using biological data obtained from amplicon sequencing of human skin swab specimens and oral rinses from healthy individuals. CONCLUSIONS: PVAmpliconFinder identified putative new HPV sequences, including one that was validated by wet-lab experiments. PVAmpliconFinder can be easily modified and applied to other viral families. PVAmpliconFinder addresses a gap by providing a solution for the analysis of NGS amplicon sequencing, increasingly used in clinical research. The PVAmpliconFinder workflow, along with its source code, is freely available on the GitHub platform: https://github.com/IARCbioinfo/PVAmpliconFinder.

Dynamics of fintech terms in news and blogs and specialization of companies of the fintech industry.

We perform a large scale analysis of a list of fintech terms in (i) news and blogs in the English language and (ii) professional descriptions of companies operating in many countries. The occurrence and the co-occurrence of fintech terms and locutions show a progressive evolution of the list of fintech terms in a compact and coherent set of terms used worldwide to describe fintech business activities. By using methods of complex networks that are specifically designed to deal with heterogeneous systems, our analysis of a large set of professional descriptions of companies shows that companies having fintech terms in their description present over-expressions of specific attributes of country, municipality, and economic sector. By using the approach of statistically validated networks, we detect geographical and economic over-expressions of a set of companies related to the multi-industry, geographically, and economically distributed fintech movement.

Synergistic Information Transfer in the Global System of Financial Markets.

Uncovering dynamic information flow between stock market indices has been the topic of several studies which exploited the notion of transfer entropy or Granger causality, its linear version. The output of the transfer entropy approach is a directed weighted graph measuring the information about the future state of each target provided by the knowledge of the state of each driving stock market index. In order to go beyond the pairwise description of the information flow, thus looking at higher order informational circuits, here we apply the partial information decomposition to triplets consisting of a pair of driving markets (belonging to America or Europe) and a target market in Asia. Our analysis, on daily data recorded during the years 2000 to 2019, allows the identification of the synergistic information that a pair of drivers carry about the target. By studying the influence of the closing returns of drivers on the subsequent overnight changes of target indexes, we find that (i) Korea, Tokyo, Hong Kong, and Singapore are, in order, the most influenced Asian markets; (ii) US indices SP500 and Russell are the strongest drivers with respect to the bivariate Granger causality; and (iii) concerning higher order effects, pairs of European and American stock market indices play a major role as the most synergetic three-variables circuits. Our results show that the Synergy, a proxy of higher order predictive information flow rooted in information theory, provides details that are complementary to those obtained from bivariate and global Granger causality, and can thus be used to get a better characterization of the global financial system.

National clinical practice guidelines for allergen immunotherapy: An international assessment applying AGREE-II.

BACKGROUND: Since 1988, numerous allergen immunotherapy guidelines (AIT-GLs) have been developed by national and international organizations to guide physicians in AIT. Even so, AIT is still severely underused. OBJECTIVE: To evaluate AIT-GLs with AGREE-II, developed in 2010 by McMaster University methodologists to comprehensively evaluate GL quality. METHODS: Allergist, from different continents, knowledgeable in AIT and AGREE-II trained were selected into the project team. The project received methodologists' guidance. AIT-GLs in any language were sought from 1980 to 2016; AIT-GLs were AGREE II-evaluated by at least 2 team members, independently; discrepancies were resolved in a second round, by team discussion or methodologists' consulting. RESULTS: We found 31 AIT-GLs (15 post-2010), ranging from local consensus reports to international position papers (EAACI, AAAAI-ACAAI, WAO). Pre-2010 GLs scored 1.6-4.6 (23%-67%) and post-2010 GLs scored 2.1-6 (30%-86%), on a 7-point Likert scale. The highest scores went to: German-Austrian-Swiss (6.0), Mexican (5.1), and the AAAAI/ACAAI AIT-GL (4.7). These were also the only 3 GLs that received "yes" of both evaluators to the item: "I would recommend this GL for use." The domains of "Stakeholder involvement" and "Rigor of Development" only scored 3/7, and "Applicability" scored the lowest. Strikingly, newer GLs only scored clearly better in "Editorial independence" and "Global evaluation." CONCLUSIONS: In AIT-GLs, there is still a lot of room for improvement, especially in domains crucial for the dissemination. For some GLs, the "Scientific rigor" domain flawed. When resources are limited, transculturizing a high-quality GL might be preferable over developing a GL from zero. Our study and AGREE-II could help to select the best candidate. CLINICAL IMPLICATIONS: We here evaluate allergen immunotherapy guideline (AIT-GL) quality. Only high-quality AIT-GLs should be consulted for AIT management decisions. In low-resource settings, transculturization of these is preferred over developing low-quality guidelines.

Renal safety after one year of sofosbuvir-based therapy for chronic hepatitis C: A Brazilian "real-life" study.

WHAT IS KNOWN AND OBJECTIVE: Sofosbuvir(SOF)-based regimens have been administrated with excellent efficacy in chronic hepatitis C. Few uncontrolled ("real-life") studies consider the assessment of renal function when evaluating their post-treatment outcomes. This study aims to evaluate renal biomarkers in a "real-life" experience with chronic hepatitis C patients treated with SOF therapy in a long-term follow-up. METHODS: Serum and urinary biomarkers were analysed before, at the end of therapy (EoT), after 12 weeks (sustained virological response-SVR) and one year (1y) post-treatment. Patients were categorized according to baseline glomerular filtration rate (GFR-cut-off 45 mL/min/1.73 m2 ). RESULTS: Ninety-four patients with a mean age of 59.9 ± 8.5 years were included; 98.9% of patients reached SVR. Significant improvement in renal biomarkers was observed in patients with GFR ≥45 mL/min/1.73 m2 , as indicated by a progressive increase in mean GFR values until 1y. No evidence of tubular dysfunction was identified. Patients with baseline GFR <45 mL/min/1.73 m2 did not experience alterations in renal biomarkers; however, a mean change of +10.7 in GFR values was observed. We noticed significant upper stage transition in the CKD classification, and 58.7% of patients achieved G1 stage at 1y (P < .0001). WHAT IS NEW AND CONCLUSION: In a "real-life experience" of a Brazilian centre, SOF therapy appears to guarantee renal safety for patients with chronic hepatitis C followed until one year after treatment.

Sleep disorders in Latin-American children with asthma and/or allergic rhinitis and normal controls.

BACKGROUND: Asthma and/or allergic rhinitis have been associated with sleep disorders. The aim of this study was to evaluate sleep disorders in Latin-American children (4-10 years) from nine countries, with persistent asthma (A) and/or allergic rhinitis (AR) and in normal controls (C). METHODS: Parents from 454 C children and 700 A and/or AR children followed up in allergy reference clinics completed the Children's Sleep Habits Questionnaire (CSHQ) which is a retrospective one-week questionnaire composed of 33 questions composed of seven subscales (bedtime resistance, sleep duration, sleep anxiety, night wakings, parasomnias, sleep-disordered breathing and daytime sleepiness). The total scale of CSHQ and the subscales were compared between groups C and A+AR, A (n=285) vs. AR (n=390), and between controlled A (CA, n=103) vs. partially controlled/uncontrolled A (UA, n=182). RESULTS: The comparison between C and A+AR showed no significant differences in age (6.7 years vs. 7.0 years, respectively), mean Body Mass Index and total scale of CSHQ (53.3 vs. 63.2, respectively) and the subscales were significantly higher in the A+AR group. Comparison between groups A and AR, except for sleep anxiety, showed significantly higher values for CSHQ total scale (66.9 vs. 61.0, respectively) and subscales for group A. The UA group showed significantly higher values for total CSHQ scale and subscales in comparison to CA (71.1 vs. 59.4, respectively). CONCLUSIONS: Latin-American children with asthma and/or allergic rhinitis showed sleep disorders identified by the CSHQ when compared to normal controls. Despite being treated, asthma causes sleep impairment, especially when uncontrolled.

Sleep-related disorders in Latin-American children with atopic dermatitis: A case control study.

BACKGROUND: Atopic dermatitis (AD) has been associated with impairment of sleep. The aim of this study was to evaluate sleep disorders in AD Latin-American children (4-10 years) from nine countries, and in normal controls (C). METHODS: Parents from 454 C and 340 AD children from referral clinics answered the Children Sleep Habits Questionnaire (CSHQ), a one-week retrospective 33 questions survey under seven items (bedtime resistance, sleep duration, sleep anxiety, night awakening, parasomnias, sleep-disordered breathing and daytime sleepiness). Total CSHQ score and items were analysed in both C and AD groups. Spearman's correlation coefficient between SCORAD (Scoring atopic dermatitis), all subscales and total CSHQ were also obtained. RESULTS: C and AD groups were similar regarding age, however, significantly higher values for total CSHQ (62.2±16.1 vs 53.3±12.7, respectively) and items were observed among AD children in comparison to C, and they were higher among those with moderate (54.8%) or severe (4.3%) AD. Except for sleep duration (r=-0.02, p=0.698), there was a significant Spearman's correlation index for bedtime resistance (0.24, p<0.0001), sleep anxiety (0.29, p<0.0001), night awakening (0.36, p<0.0001), parasomnias (0.54, p<0.0001), sleep-disordered breathing (0.42, p<0.0001), daytime sleepiness (0.26, p<0.0001) and total CSHQ (0.46, p<0.0001). AD patients had significantly higher elevated body mass index. CONCLUSION: Latin-American children with AD have sleep disorders despite treatment, and those with moderate to severe forms had marked changes in CSHQ.

Similar biological activity in skin prick test for Oralair® (8200 BAU) and Grazax® (6200 BAU) reinforces effective SLIT dosing level.

In Europe, allergen extracts are standardized based on skin prick wheal size in 20-30 allergic subjects. To understand the biological activity of clinically effective Sublingual immunotherapy, we used this method to determine the biological activity of solution and tablet Timothy grass pollen (TIM) extracts, compared to an FDA-approved extract (Reference) of 10 000 BAU/ml. Blinded, quadruplicate skin prick tests with concentrate and three serial half-log dilutions allowed the construction of a semilogarithmic regression line per extract. Bioequivalent allergy units (BAU) values were obtained from the comparison with reference. Extracts and dilutions showed a neat linear dose response (all: R2 > 0.98) in 33 rhinitis patients. Relative potencies: Staloral® 12 000 BAU/ml, Soluprick® 10 300 BAU/ml, Oralair® 8200 BAU, and Grazax® 6200 BAU. Even though all extract concentrates differed in wheal size (P = 0.01-0.001), Grazax® producing a 25% smaller wheal size than Oralair® , and the biological activity of these clinically effective TIM tablets led in the same range (6200-8200 BAU; 0.92-1.23 cm2 ). SLIT dose-finding studies for other pollens might start with allergen extracts producing 1.1 cm2 wheal surface.

Molecular-based diagnosis of respiratory allergic diseases in children from Curitiba, a city in Southern Brazil.

BACKGROUND: Prevalence of respiratory allergic diseases has increased worldwide. Identification of the aeroallergens involved in allergenic sensitisation is important for diagnosis, treatment and prevention. OBJECTIVE: To verify the molecular pattern of sensitisation to aeroallergens in patients with allergic respiratory diseases using microarray technique for specific IgE antibody detection. METHODS: Cross-sectional study of 101 children with allergic rhinitis was followed in an outpatient clinic. All patients had positive skin prick tests (SPT) to at least one of the following antigens: Dermatophagoides pteronyssinus, Blomia tropicalis, Blattella germanica, Lolium multiflorum, and dog and cat epithelium. Serum specific IgE antibodies (sIgE) to mites, animal epithelia, fungi, cockroach and pollens components were determined by ImmunoCAP ISAC. RESULTS: sIgE to group 1 and 2 mite allergens showed higher positive rates: Der p 1 (74.2%), Der p 2 (73.3%), Der f 1 (74.2%), Der f 2 (72.3%). sIgE to animal epithelia were less frequent, Can f 1, Can f 2, Can f 3 in 4.9%, 2.9%, 1.9% respectively and Fel d 1, Fel d 2, Fel d 4 in 16.8%, 0.9% and 1.9%. respectively. Sensitisation to fungi and cockroach were rare, except for Bla g 7, to which 16.8% were positive. There was no significant recognition for tree pollens group. For grass, sIgE were detected to Cyn d 1 in 16.8%, Phl p 1 and Phl p 4 in 14.8% and 12.9%, respectively. CONCLUSION: Knowing that the pattern of allergic sensitisation varies according to environment and population, our results reinforce the need for local studies, using molecular-based diagnosis.

Allergic rhinitis in preschool children from Southern Brazil.

There are few published studies on prevalence of allergic rhinitis in preschool children. The aims of this study were to verify the prevalence, clinical characteristics, and treatment of allergic rhinitis (AR) symptoms in the first year of life adding supplementary questions to the EISL instrument. A cross-sectional study used Phase III EISL written questionnaire in addition to modified allergic rhinitis ISAAC questions. One thousand and three parents of infants answered the questionnaire: 484 (48.3%) had at least one sneezing, or a runny or blocked nose episodes without cold or flu in the first year of life. A quarter of infants had recurrent wheezing (≥3 episodes) and more frequent in the presence of AR symptoms. Physician diagnosis of AR and the use of intranasal steroids and both antihistamines and intranasal steroids were more common among those infants with AR symptoms. The prevalence of AR symptoms was high and starting early in life.

Complex networks approach to study comorbidities in patients with unruptured intracranial aneurysms.

The role of complex network analysis in patients with diagnosis of unruptured intracranial aneurysm is unexplored. The objective of this study is to assess the applicability of this methodology in aneurysm patients. We retrospectively analyze comprehensive unbiased local digital data of a large number of patients treated for any reason between January 2004 and July 2019. We apply an age-cohort approach to a total of 628,831 patients and construct the diagnostic history of each patient-and include the information how old the patient was when diagnosed for the first time with each diagnosis coded according to International Classification of Diseases. For each cohort of age within a 10 year interval and for each gender, we construct a statistically validated comorbidity network and focused on crucial comorbidity links that the aneurysm code has to other disease codes within the whole network. For all cohorts of different age and gender, the analysis shows that 267 diagnose codes have nearest neighbour statistically validated links to unruptured aneurysm ICD code. Among the 267 comorbidities, 204 (76%) were found in patients aged from 40 to 69-years old. Patterns of connectivity with aneurysms were found for smoking, hypertension, chronic obstructive pulmonary disease, dyslipidemia, and mood disorders. A few uncommon connections are also detected in cohorts of female patients. Our study explored the applicability of network analysis and statistical validation in aneurysm observational study.

Two-step estimators of high-dimensional correlation matrices.

We investigate block diagonal and hierarchical nested stochastic multivariate Gaussian models by studying their sample cross-correlation matrix on high dimensions. By performing numerical simulations, we compare a filtered sample cross-correlation with the population cross-correlation matrices by using several rotationally invariant estimators (RIEs) and hierarchical clustering estimators (HCEs) under several loss functions. We show that at large but finite sample size, sample cross-correlations filtered by RIE estimators are often outperformed by HCE estimators for several of the loss functions. We also show that for block models and for hierarchically nested block models, the best determination of the filtered sample cross-correlation is achieved by introducing two-step estimators combining state-of-the-art nonlinear shrinkage models with hierarchical clustering estimators.

Evaluation of human papillomavirus DNA in colorectal cancer and adjacent mucosal tissue samples.

BACKGROUND: Although the role of viral agents, such as human papillomavirus (e.g. HPV16, HPV18) in colorectal cancer (CRC) has been previously investigated, results remain inconclusive. METHODS: To further evaluate the involvement of oncogenic HPV types in CRC, 40 frozen neoplastic and 40 adjacent colonic tissues collected from Italian patients were analyzed by Luminex-based assays that detect a broad spectrum of HPV types, i.e. Alpha (n = 21), Beta (n = 46) and Gamma HPVs (n = 52). In addition, 125 frozen CRC samples and 70 surrounding mucosal tissues were collected from Czech patients and analyzed by broad spectrum PCR protocols: (i) FAP59/64, (ii) FAPM1 and (iii) CUT combined with Next Generation Sequencing (NGS). RESULTS: Using Luminex-basedassays, DNA from HPV16 was detected in 5% (2/40) CRC tissues from Italian patients. One HPV16 DNA-positive CRC case was subsequently confirmed positive for E6*I mRNA. Cutaneous beta HPV types were detected in 10% (4/40) adjacent tissues only, namely HPV111 (n = 3) and HPV120 (n = 1), while gamma HPV168 (n = 1) and HPV199 (n = 1) types were detected in adjacent and in tumor tissues, respectively. The NGS analysis of the CRC Czech samples identified HPV sequences from mucosal alpha-3 (HPV89), alpha-7 (HPV18, 39, 68 and 70) and alpha-10 species (HPV11), as well as cutaneous beta-1 (HPV20, 24, 93, 98, 105,124) beta-2 (HPV23), beta-3 (HPV49) and gamma-1 species (HPV205). CONCLUSIONS: Our findings indicate that HPV types belonging to the mucosal alpha, and the 'cutaneous' beta and gamma genera can be detected in the colonic mucosal samples with a low prevalence rate and a low number of HPV reads by Luminex and NGS, respectively. However, additional studies are required to corroborate these findings.

Anaphylaxis in Latin American children and adolescents: the Online Latin American Survey on Anaphylaxis (OLASA).

OBJECTIVES: To identify the main clinical manifestations, triggers, and treatment of severe allergic reactions (SAR) in children and adolescents (n=191, up to 18 years of age) seen by allergologists and registered in the Online Latin American Survey of Anaphylaxis (OLASA). RESULTS: 53.0% of the patients were males and the aetiological agent was identified in 85.5% of them as follows: foods (36.1%), drugs (27.7%), and insect stings (26.2%). The most common symptoms during an acute episode were cutaneous (94.2%), and respiratory (78.5%). Most patients were treated in emergency setting, yet only 34.6% received parenteral epinephrine and 14.3% had to be hospitalised. CONCLUSION: Cutaneous symptoms ranked the order of clinical presentation of SAR. Food was the main triggering agent in the younger cases and insect sting and drugs in the adolescents. Treatment provided for SAR was not appropriate. It is necessary to improve educational programmes in order to enhance the knowledge on this potentially fatal emergency.

Quantifying the relationship between specialisation and reputation in an online platform.

Online platforms implement digital reputation systems in order to steer individual user behaviour towards outcomes that are deemed desirable on a collective level. At the same time, most online platforms are highly decentralised environments, leaving their users plenty of room to pursue different strategies and diversify behaviour. We provide a statistical characterisation of the user behaviour emerging from the interplay of such competing forces in Stack Overflow, a long-standing knowledge sharing platform. Over the 11 years covered by our analysis, we represent the interactions between users and topics as bipartite networks. We find such networks to display nested structures akin to those observed in ecological systems, demonstrating that the platform's user base consistently self-organises into specialists and generalists, i.e., users who focus on narrow and broad sets of topics, respectively. We relate the emergence of these behaviours to the platform's reputation system with a series of data-driven models, and find specialisation to be statistically associated with a higher ability to post the best answers to a question. We contrast our findings with observations made in top-down environments-such as firms and corporations-where generalist skills are consistently found to be more successful.

MinION nanopore sequencing and assembly of a complete human papillomavirus genome.

BACKGROUND: The MinION sequencer belongs to the third generation of sequencing technology that allows for the generation of ultra-long reads, representing a potentially more effective approach to characterize entire viral genome sequences than other time-consuming and low-throughput methodologies. METHODS: We report the use of the MinION nanopore sequencer to sequence the full-length genome of human papillomavirus (HPV)-ICB2 (7441 bp), which was previously characterized in our laboratory. Three independent MinION libraries were prepared and sequenced using either three consecutive 12 -h runs (Protocol A) or a single run of 48 h starting from a pool of three barcoded DNA libraries (Protocol B). A fully automated bioinformatics pipeline was developed for the reconstruction of the viral genome. RESULTS: Protocols A and B generated 9,354,933 and 3,255,879 reads, respectively. Read length N50 values ranged between 6976 and 7360 nucleotides over the four sequencing runs. Bioinformatics analysis showed that both protocols allowed for the reconstruction of the whole viral genome, with pairwise percentages of identity to HPV-ICB2 of 100 % for protocol A and 99.98 % for protocol B. CONCLUSION: Our results show that the use of the MinION nanopore sequencer represents an effective strategy for whole-genome sequencing of HPVs with a minimal error rate.

Diversity of human papillomavirus in the anal canal of HIV-positive and HIV-negative men.

BACKGROUND: To characterize the HPV diversity in the anal mucosa of men with different sexual behavior and HIV status by next-generation sequencing (NGS). METHODS: Anal swabs from HIV-positive (n = 94; mean age, 38 years) and HIV-negative (n = 100; mean age, 37.5 years) men who have sex with men (MSM) and HIV-negative men (predominantly men who have sex with women, MSW) (n = 99; mean age, 38.2 years) were analyzed by broad-spectrum PCR protocols combined with NGS. FINDINGS: Alpha HPV types (n = 74) were detected mainly in the MSM groups (HPV6, 11, and 43 were the most abundant types) compared with MSW (n = 16) (HPV11, 32, and 87 were among the most abundant). In contrast, beta HPVs were more abundantly detected among MSW (n = 45) than in the HIV-positive (n = 16) and HIV-negative (n = 26) MSM groups. Gamma HPVs were detected almost equally in HIV-positive MSM (n = 62), HIV-negative MSM (n = 58), and MSW (n = 57). In addition, 31 putative novel PV types were identified. CONCLUSIONS: Our data show that beta and gamma HPV types are present in the anal mucosa, thus reinforcing the existing evidence that they can be detected at anatomical sites other than skin. Alpha and beta HPV distribution among these three groups appears to vary according to sexual behavior.