Human T-lymphotropic viruses (HTLVs) are deltaretroviruses infecting millions of individuals worldwide, with HTLV-1 and HTLV-2 being the most widespread and clinically relevant types. HTLV-1 is associated with severe diseases such as adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), while HTLV-2 shows a lower pathogenic potential, with occasional links to neurological disorders. HTLV-3 and HTLV-4, identified in Central Africa, remain poorly characterized but are genetically close to their simian counterparts, indicating recent zoonotic transmission events. HTLVs replicate through a complex cycle involving cell-to-cell transmission and clonal expansion of infected lymphocytes. Viral persistence is mediated by regulatory and accessory proteins, notably Tax and HBZ in HTLV-1, which alter host cell signaling, immune responses, and genomic stability. Integration of proviral DNA into transcriptionally active regions of the host genome may contribute to oncogenesis and long-term viral latency. Differences in viral protein function and intracellular localization contribute to the distinct pathogenesis observed between HTLV-1 and HTLV-2. Geographically, HTLV-1 shows endemic clusters in southwestern Japan, sub-Saharan Africa, the Caribbean, South America, and parts of the Middle East and Oceania. HTLV-2 is concentrated among Indigenous populations in the Americas and people who inject drugs in Europe and North America. Transmission occurs primarily via breastfeeding, sexual contact, contaminated blood products, and, in some regions, zoonotic spillover. Diagnostic approaches include serological screening (ELISA, Western blot, LIA) and molecular assays (PCR, qPCR), with novel biosensor and AI-based methods under development. Despite advances in understanding viral biology, therapeutic options remain limited, and preventive strategies focus on transmission control. The long latency period, lack of effective treatments, and global neglect complicate public health responses, underscoring the need for increased awareness, research investment, and targeted interventions.

This review addresses the critical conservation challenges faced by Pinna nobilis, the noble pen shell, a keystone umbrella species in Mediterranean marine ecosystems. Since 2016, the species has experienced catastrophic population declines due to mass mortality events likely driven by protozoan, bacterial, and viral infections. Despite these severe circumstances, small resilient populations persist in select estuaries and coastal lagoons across the Mediterranean, offering potential for recovery. We provide a comprehensive overview on research dedicated to Pinna nobilis’ biology, genetic variation, disease dynamics, and environmental factors influencing its survival, with a focus on refugia where populations still endure. Remarkably, recent studies have revealed signs of resistance in certain individuals and the potential for hybridisation with Pinna rudis. In this context, the possible impact of the increasing occurrence of hybridisation between Pinna nobilis and Pinna rudis on the conservation of their genetic diversity should be carefully considered. This review highlights the importance of ongoing conservation efforts including habitat restoration, protection of remaining populations, assessment of past and present genetic variability, and the development of captive breeding programmes. We aim to elucidate the need for continued studies on Pinna nobilis’ biodiversity, particularly its evolutionary dynamics, genetic makeup, and the interplay of environmental variables influencing its survival and persistence.

The Ohrid trout, Salmo letnica, is an endemic species of Lake Ohrid, one of Europe’s oldest lakes, located on the Albania-North Macedonia border. This species exhibits distinct morphotypes—Salmo letnica typicus, Salmo letnica aestivalis, Salmo letnica balcanicus, and Salmo letnica lumi—that differ in morphology and spawning behaviour. However, the extent of their genetic differentiation remains unclear. This study aimed to investigate the genetic variability and population structure of Salmo letnica morphotypes using the mitochondrial Control Region as molecular marker. We obtained 127 sequences from Salmo letnica morphotypes and compared them with sequences from other species within the genus Salmo. Phylogenetic and clustering analyses revealed no significant genetic structuring among the four morphotypes, suggesting an ecological differentiation not (yet) fixed at mitochondrial level. Additionally, our findings suggest that the modern Salmo letnica population likely originated in Lake Ohrid from Salmo farioides founders through evolutionary differentiation, potentially driven by environmental changes. Future studies incorporating a larger number of samples from both Salmo letnica and Salmo farioides are essential to fully understand the evolutionary and ecological dynamics of Salmo letnica morphotypes.

We adopted a morphometric approach to provide statistical support for the description of two different morphotypes (I, reproductive, II, non-reproductive) firstly observed in Procambarus clarkii specimens caught in a population from Sardinia Island (western Mediterranean). The morphometric study was preceded by molecular taxonomic identification using the mitochondrial Cytochrome C Oxidase subunit I (COI) gene. The presence or absence of the pathogen Aphanomyces astaci, responsible for the plague, was also investigated using the ribosomal Internal Transcribed Spacer (ITS) marker. The estimation of the size at onset of maturity (SOM) was further performed in males. Finally, the population structure was examined. Our results confirmed the entirety of the individuals as P. clarkii, and the absence of the pathogen A. astaci. Morphological analysis revealed a significant correlation between chela and carapace lengths, while intra- and inter-sexual dimorphism in the chela length confirmed the occurrence of the two morphotypes. The SOM in males was established between 35.0 and 37.1 mm carapace length. Finally, the size-population structure showed a Gaussian distribution. The recognition of the two distinct morphotypes in the crayfish could be useful as an additional tool not only to identify the reproductive period of this invasive crustacean but also to enrich the guidelines for the correct taxonomic identification of the species.

SARS-CoV-2 XFG (nicknamed Stratus), a recombinant lineage arising from LP.8.1.2 and LF.7, is currently the most prevalent circulating lineage. Although most recombinant lineages do not pose a significant public health concern, some have shown the capacity to emerge and spread, highlighting the importance of their investigation. In this context, we performed a genome-based analysis to assess the genetic variability of XFG and to identify its recombination breakpoint. The breakpoint was mapped to approximately position 1507 within the spike (S) gene, in the distal region of the receptor-binding domain. This configuration suggests that LP.8.1.2 contributed the genomic backbone as the acceptor, whereas LF.7 acted as the donor. Phylodynamic survey suggests that XFG originated in early 2024, approximately 10 months before its first genomic detection. Bayesian Skyline Plot revealed a transient expansion phase beginning in August 2024, followed by a plateau, indicating limited and non-sustained growth. The estimated evolutionary rate of XFG (2.90 × 10^-4 subs/site/year) was comparable to those of its parental lineages, supporting a relatively low level of genetic variability. Overall, these findings suggest that the widespread prevalence of XFG is more likely driven by lineage turnover rather than increased transmissibility, highlighting the importance of continuous genomic surveillance for monitoring emerging SARS-CoV-2 lineages.

Understanding genetic diversity and population structure is essential for the sustainable management of freshwater fish, particularly in systems influenced by long-term stocking. In this context, the genetic status of Albanian common carp (Cyprinus carpio) remains poorly understood. Here, 125 individuals from five populations representing natural lakes (Ohrid and Shkodra), semi-managed freshwater systems (Prespa and Belshi), and a hatchery stock (Tapiza) were genotyped at 12 polymorphic microsatellite loci. High genetic diversity was detected across all populations, with low genetic differentiation and relevant estimates of gene flow. Bayesian clustering identified two main genetic groups, with natural lake populations predominantly represented by a single genetic lineage and managed systems showing higher admixture. Multivariate and phylogenetic analyses supported a close genetic relationship between Ohrid and Shkodra natural lake populations. These patterns may reflect historical stocking and translocation programmes, potentially involving genetically similar or shared broodstock sources, which may have contributed to the observed genetic similarity among populations while maintaining high levels of within-population genetic diversity. The more homogeneous genetic composition of natural lake populations may also reflect local environmental conditions that influenced the distribution of allelic variants among populations. Overall, this study provides a comprehensive genetic assessment of Albanian common carp and establishes a baseline for future sustainable management plans.