Alessandra Lo Presti

Analysis of the ORFK1 hypervariable regions reveal distinct HHV-8 clustering in Kaposi’s sarcoma and non-Kaposi’s cases

BackgroundClassical Kaposi’s Sarcoma (cKS) is a rare vascular tumor, which develops in subjects infected with Human Herpesvirus-8 (HHV-8). Beside the host predisposing factors, viral genetic variants might possibly be related to disease development. The aim of this study was to identify HHV-8 variants in patients with cKS or in HHV-8 infected subjects either asymptomatic or with cKS-unrelated cutaneous lymphoproliferative disorders.MethodsThe VR1 and VR2 regions of the ORF K1 sequence were analyzed in samples (peripheral blood and/or lesional tissue) collected between 2000 and 2010 from 27 subjects with HHV-8 infection, established by the presence of anti-HHV-8 antibodies. On the basis of viral genotyping, a phylogenetic analysis and a time-scaled evaluation were performed.ResultsTwo main clades of HHV-8, corresponding to A and C subtypes, were identified. Moreover, for each subtype, two main clusters were found distinctively associated to cKS or non-cKS subjects. Selective pressure analysis showed twelve sites of the K1 coding gene (VR1 and VR2 regions) under positive selective pressure and one site under negative pressure.ConclusionThus, present data suggest that HHV-8 genetic variants may influence the susceptibility to cKS in individuals with HHV-8 infection.

Phylogeography and epidemiological history of West Nile virus genotype 1a in Europe and the Mediterranean basin.

Aim of this study was to reconstruct the temporal and spatial phylodynamics of WNV-1a, the genotype to which the majority of European/Mediterranean viral strains belongs, by using sequences retrieved from public databases. WNV-1a isolates segregated into two major clades: the recent West Mediterranean sequences formed a single monophyletic group within clade A. Clade B included sequences from East Mediterranean and America. Phylogeographic analysis suggested that WNV-1a probably originated in sub-Saharan Africa in the early XXth century, and then spread northwards since the late 1970s, via two routes: one crossing Eastern Mediterranean and the other the Western Mediterranean countries. Our data suggest that the circulation of the virus in a given geographical area usually precedes the onset of the outbreak by one year or more, and underline the importance of the spatial-temporal phylodynamics reconstruction in clarifying the recent epidemiology and in setting up an efficient surveillance system for emerging/reemerging zoonosis.

Identification of Merkel cell polyomavirus in the lower respiratory tract of Italian patients.

Merkel cell polyomavirus (MCPyV) has been found to be integrated monoclonally in a rare skin cancer named Merkel cell carcinoma. More recently, MCPyV has been detected in the upper respiratory tract of pediatric and adult patients. However, the mode of transmission and pathogenic role of MCPyV in the respiratory system has not been determined. In this study, MCPyV was sought in the lower respiratory tract of adult patients admitted to the hospital. MCPyV DNA was detected in 15 (17.24%) out of 87 lower respiratory tract samples. Most of the patients with MCPyV were over 50 years old. Nucleotide sequence of the t‐antigen of MCPyV identified in respiratory secretions showed a homology to those found in Merkel cell carcinoma. In addition, phylogenetic analysis undertaken on the t‐antigen sequences of Italian isolates and other MCPyVs identified in healthy and cancer tissues showed that all these isolates belonged to the same clade. Selective pressure analysis for the t‐antigen revealed the presence of five sites under positive selection (ω = 4.3), with a posterior probabilities above 0.99. The α parameter of the gamma distribution was 0.01, showing that this distribution has a characteristic L‐shape and suggesting a strong nucleotide substitution rate heterogeneity across sites. This study shows that MCPyV can infect the lower respiratory tract, but further investigations are needed to define its pathogenic role in respiratory diseases. J. Med. Virol. 82:505–509, 2010.

Chikungunya virus, epidemiology, clinics and phylogenesis: A review.

Chikungunya virus is a mosquito-transmitted alphavirus that causes chikungunya fever, a febrile illness associated with severe arthralgia and rash. Chikungunya virus is transmitted by culicine mosquitoes; Chikungunya virus replicates in the skin, disseminates to liver, muscle, joints, lymphoid tissue and brain, presumably through the blood. Phylogenetic studies showed that the Indian Ocean and the Indian subcontinent epidemics were caused by two different introductions of distinct strains of East/Central/South African genotype of CHIKV. The paraphyletic grouping of African CHIK viruses supports the historical evidence that the virus was introduced into Asia from Africa. Phylogenetic analysis divided Chikungunya virus isolates into three distinct genotypes based on geographical origins: the first, the West Africa genotype, consisted of isolates from Senegal and Nigeria; the second contained strains from East/Central/South African genotype, while the third contained solely Asian. The most recent common ancestor for the recent epidemic, which ravaged Indian Ocean islands and Indian subcontinent in 2004 - 2007, was found to date in 2002. Asian lineage dated about 1952 and exhibits similar spread patterns of the recent Indian Ocean outbreak lineage, with successive epidemics detected along an eastward path. Asian group splitted into two clades: an Indian lineage and a south east lineage. Outbreaks of Chikungunya virus fever in Asia have not been associated necessarily with outbreaks in Africa. Phylogenetic tools can reconstruct geographic spread of Chikungunya virus during the epidemics wave. The good management of patients with acute Chikungunya virus infection is essential for public health in susceptible areas with current Aedes spp activity.

Epidemiological history and phylogeography of West Nile virus lineage 2

West Nile virus (WNV) was first isolated in Uganda. In Europe WNV was sporadically detected until 1996, since then the virus has been regularly isolated from birds and mosquitoes and caused several outbreaks in horses and humans. Phylogenetic analysis showed two main different WNV lineages. The lineage 1 is widespread and segregates into different subclades (1a-c). WNV-1a includes numerous strains from Africa, America, and Eurasia. The spatio-temporal history of WNV-1a in Europe was recently described, identifying two main routes of dispersion, one in Eastern and the second in Western Europe. The West Nile lineage 2 (WNV-2) is mainly present in sub-Saharan Africa but has been recently emerged in Eastern and Western European countries. In this study we reconstruct the phylogeny of WNV-2 on a spatio-temporal scale in order to estimate the time of origin and patterns of geographical dispersal of the different isolates, particularly in Europe. Phylogeography findings obtained from E and NS5 gene analyses suggest that there were at least two separate introductions of WNV-2 from the African continent dated back approximately to the year 1999 (Central Europe) and 2000 (Russia), respectively. The epidemiological implications and clinical consequences of lineage 1 and 2 cocirculation deserve further investigations.

Population dynamics of HIV-1 subtype B in a cohort of men-having-sex-with- men in Rome, Italy

A recent increase in HIV diagnoses among men-having-sex-with-men (MSM) has been shown by surveillance data from Europe and Italy, and new approaches to inferring viral population dynamics from heterochronously sampled gene sequences have been developed. The aim of this study was to reconstruct the epidemiological history of HIV-1 subtype B in a homogeneous group of Italian MSM using a coalescent-based Bayesian framework. A total of 125 HIV-1 subtype B pol sequences were analyzed using Bayesian methods and a relaxed molecular clock to reconstruct their dated phylogeny and estimate population dynamics. At least 10 epidemiological clusters of 3-9 isolates were identified: half including the largest clades originated in the early 1990s and the other half radiated from 1999. Demographic analysis showed that the HIV epidemic grew in accordance with a logistic model characterized by a rapid exponential increase in the effective number of infections (r = 1.54 year−1) starting from the early 1980s and reaching a plateau 10 years later. Our data suggest that the HIV B epidemic entered our MSM population through multiple transmission chains about 20 years later than in other Western European country. Epidemiological clusters originating in the early 2000s suggest a recent re-emergence of HIV in Italian MSM.

Enigmatic origin of hepatitis B virus: An ancient travelling companion or a recent encounter?

Hepatitis B virus (HBV) is the leading cause of liver disease and infects an estimated 240 million people worldwide. It is characterised by a high degree of genetic heterogeneity because of the use of a reverse transcriptase during viral replication. The ten genotypes (A-J) that have been described so far further segregate into a number of subgenotypes which have distinct ethno-geographic distribution. Genotypes A and D are ubiquitous and the most prevalent genotypes in Europe (mainly represented by subgenotypes D1-3 and A2); genotypes B and C are restricted to eastern Asia and Oceania; genotype E to central and western Africa; and genotypes H and F (classified into 4 subgenotypes) to Latin America and Alaska. This review summarises the data obtained by studying the global phylodynamics and phylogeography of HBV genotypes, particularly those concerning the origin and dispersion histories of genotypes A, D, E and F and their subgenotypes. The lack of any consensus concerning the HBV substitution rate and the conflicting data obtained using different calibration approaches make the time of origin and divergence of the various genotypes and subgenotypes largely uncertain. It is hypothesised that HBV evolutionary rates are time dependent, and that the changes depend on the main transmission routes of the genotypes and the dynamics of the infected populations.

Spatial and Temporal Dynamics of Hepatitis B Virus D Genotype in Europe and the Mediterranean Basin

Hepatitis B virus genotype D can be found in many parts of the world and is the most prevalent strain in south-eastern Europe, the Mediterranean Basin, the Middle East, and the Indian sub-continent. The epidemiological history of the D genotype and its subgenotypes is still obscure because of the scarcity of appropriate studies. We retrieved from public databases a total of 312 gene P sequences of HBV genotype D isolated in various countries throughout the world, and reconstructed the spatio-temporal evolutionary dynamics of the HBV-D epidemic using a Bayesian framework. The phylogeographical analysis showed that India had the highest posterior probability of being the location of the tree root, whereas central Asia was the most probable location of the common ancestor of subgenotypes D1–D3. HBV-D5 (identified in native Indian populations) diverged from the tree root earlier than D1–D3. The time of the most recent common ancestor (tMRCA) of the tree root was 128 years ago, which suggests that the common ancestor of the currently circulating subgenotypes existed in the second half of the XIX century. The mean tMRCA of subgenotypes D1–D3 was between the 1940s and the 1950–60s. On the basis of our phylogeographic reconstruction, it seems that HBV-D reached the Mediterranean area in the middle of the XX century by means of at least two routes: the first pathway (mainly due to the spread of subgenotype D1) crossing the Middle East and reaching north Africa and the eastern Mediterranean, and the second pathway (closely associated with D2) that crossed the former Soviet Union and reached eastern Europe and the Mediterranean through Albania. We hypothesise that the main route of dispersion of genotype D was the unsafe use of injections and drug addiction.

Unusual microorganisms and antimicrobial resistances in a group of Syrian migrants: Sentinel surveillance data from an asylum seekers centre in Italy.

BACKGROUND Three years of civil war in Syria have caused death and increase of communicable diseases. The suffering population has been forced to migrate creating a fertile condition for epidemic spread of infection within the refugee camps. METHODS Forty-eight Syrian migrants, upon their arrival in Italy, were accommodated at the asylum seekers centre of Castelnuovo di Porto. They received a physical examination and were subjected to microbiological surveillance by blood, rectal, pharyngeal and nasal swabs collection and delivering to the Clinical Pathology and Microbiology Laboratory of the University Campus Bio-Medico of Rome. RESULTS All refugees resulted negative for HBV, HCV and HIV infections. In swabs a large number of unusual gram-negative bacteria species were isolated, such as Pseudomonas putida, Pseudomonas monteilii, Pseudomonas fulva, Pseudomonas moselii, Aeromonas veronii, Aeromonas caviae, Aeromonas hydrophila, Acinteobacter guilloviae, Acinteobacter lowffii; Acinetobacter johnsonii; Acinteobacter tjernbergae; Pantoea agglomerans; Pantoea calida. Among isolates, strains resistant to carbapenems, ESBL producers and methicillin resistant were found. CONCLUSIONS The microbiological surveillance performed represents a useful action to understand refugees health status and to trace unusual microorganisms movement even carriers of antimicrobial resistance during migrants traveling.

Origin, evolution, and phylogeography of recent epidemic CHIKV strains

Chikungunya virus (CHIKV) is an arthropod-borne virus of the Alphavirus genus, which is transmitted to humans by Aedes spp. mosquitoes and was firstly identified in Tanzania in the mid 1950s. In this article, the findings of a phylogenetic and phylogeographic analysis of the recent CHIKV pandemic are reported. We estimated time of origin of the ancestral virus, time and place of occurrence of A226V mutation, and the flow of viral strains from an area to the other. The Bayesian phylogenetic and phylogeographic analysis was performed on the whole dataset, which consisted of 195 E1 (envelope 1) CHIKV sequences, and on a subset (D2), including 146 of the 195 previous sequences. Using the relaxed clock model, we estimated a CHIKV E1 mean evolutionary rate (in the whole dataset) of 1.4 × 10(-3)substitution/site/year (95% highest posterior density interval HPD 6.4 × 10(-4)-2.5 × 10(-3)), and of 2.2 × 10(-3) (95% HPD 9.6 × 10(-4)-3.8 × 10(-3)) in the D2 subset, including only the strains involved in the recent Indian Ocean epidemic. The phylogeographical analysis suggested an African origin of CHIKV with a tMRCA of 146 years corresponding to 1863 (95% HPD 1741-1941). Moreover D2 subset most probably originated in Kenya, with a tMRCA corresponding to the year 2002 (95% HPD 2000-2004), then spread following two distinct routes: one throughout the Indian Ocean (Reunion, Comoros) and the other moving from India then scattered in the South East Asia and reached Italy. In conclusion, we reconstructed the geographic spread of CHIKV during the last epidemic wave, which showed an eastward path from Africa to Indian Ocean island to India, and from there to other South East Asian countries. Whether A226V variants followed the same migration path remains undefined, since local independent mutations, followed by fixation due to selective advantage conferred by better adaptation to local vectors of infection, cannot be excluded.