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Arboviral infections, transmitted to humans primarily through arthropod vectors, constitute a significant global health threat. Arboviruses, such as Dengue, Zika, Chikungunya, and West Nile viruses, continue to cause widespread outbreaks, necessitating advanced diagnostic tools. Emerging technologies including Lab On A Chip (LOC), Lab On A Disc (LOAD), Microfluidic Paper-Based Analytical Devices (µPADS), Lateral Flow Devices, CRISPR-CAS 12/13, Quartz crystal microbalance (QCM), and Nano-Technology are evaluated for their potential to enhance arboviral diagnosis, offering rapid, accurate, and point-of-care solutions. Furthermore, the identification of robust biomarkers, including Inflammatory Cytokines, Antibodies, Endothelial Activation Products and Indicators of Tissue or Organ Damage, is crucial for improving the understanding of disease pathogenesis, prognosis, and treatment response. A comprehensive analysis of potential diagnostics and biomarkers for arboviral infections sheds light on the evolving strategies to combat these medically significant diseases, ultimately contributing to more effective surveillance, diagnosis and management worldwide.

Introduction. The habitat of mosquitoes belonging to the genera Aedes spp., Culex spp., Culiseta spp. is in South and Central America, including Nicaragua. Monitoring of the spread of mosquito vectors and assessment of the infection with arboviruses can provide information on possible occurrence of new diseases or an increase in the reported cases, changes in the infectivity of viruses for humans due to changes in pathogen transmitters. The purpose of this study was isolation and identification of arboviruses belonging to the Flavivirus and Alphavirus genera from A. albopictus, A. aegypti, Culiseta spp., Culex spp. mosquitoes captured in forests of Nicaragua. Materials and methods. A. albopictus, A. aegypti, Culiseta spp., Culex spp. mosquitoes were captured during the dry season in 2021 in forested areas of Nicaragua in four different locations. Mosquitoes were sorted into pools, each containing 5-8 mosquitoes (236 pools in total). Using the reverse transcription polymerase chain reaction, the pools were tested for the presence of chikungunya (CHIKV), dengue, Zika, and yellow fever viruses. Positive pools were inoculated into the C6/36 cell culture to obtain isolates and for their further sequencing. Results. The dengue virus was detected only in Aedes spp. mosquitoes: in 7 pools — A. aegypti, in 1 — A. albopictus. CHIKV was also detected only in Aedes spp. mosquitoes: in 3 pools — A. aegypti, in 1 — A. albopictus. The sequencing of nucleotide sequences of 6К, Е1, Е2, and NS1 genes of CHIKV isolated from A. albopictus mosquitoes showed that compared to the similar gene sequences from CHIKV isolates recovered from A. aegypti mosquitoes, the 6K gene region contained 4 nucleotide and 4 amino acid substitutions, while the E1 region contained 16 nucleotide substitutions, 10 of them led to amino acid substitutions; the E2 region contained 14 nucleotide and 11 amino acid substitutions; the NS1 region contained 33 nucleotide and 19 amino acid substitutions.

Introduction. Arboviral infections are a rising public health concern not only for some individual countries, but also for the entire world due to the repeated outbreaks over the past decade.The aim was to conduct a seroprevalence study of Dengue (DENV), Zika (ZIKV), Yellow fever (YFV) and Chikungunya (CHIKV) viruses using a limited number of samples in Nicaragua.Materials and methods. Total 200 serum samples collected previously in Nicaragua were analyzed simultaneously. Commercially available diagnostic kits, as well as in-house methods were used. The avidity of antibodies (IgG) in positive serum samples was assessed after the treatment with 8M urea.Results. 85 serum samples (42.5%) contained IgG antibodies to one or several viruses simultaneously. IgG antibodies only to one virus were detected in 46 serum samples (23%) with the avidity index (AI) ≥ 30%. Among 39 samples (19.5%) that contained IgG antibodies to several viruses, only in 19 samples (9.5%) IgG antibodies with high AI (≥ 30%) to several viruses were detected. In 16 serum samples (8.0%), IgG antibodies to DENV with a high AI and antibodies to ZIKV and/or YFV with a low AI < 30% were detected.Discussion. The results obtained in ELISA testing were corrected, since only IgG antibodies with a high AI confirm the past infection. The analysis of the specific IgG antibody avidity helped not only to confirm the cases of combined or sequential infection in the past, but also to discriminate the cross-reactive IgG antibodies induced by closely related DENV, ZIKV and YFV. The presence of cross-reactive IgG antibodies, on the one hand, make it difficult to determine the real seroprevalence of flavivirus infections, and, on the other hand, may increase the risk of antibody-dependent enhancement (ADE) of the disease, which is well-known for the secondary Dengue fever and for the consecutive infection with DENV and ZIKV.Conclusion. The analysis of virus-specific antibody avidity made it possible not only to distinguish recent from the past infection, but also to discriminate the cross-reactive antibodies with the low avidity.

Introduction. Chikungunya virus infection (CKV) may lead to chronic arthritis in up to 40% of the patients. There are previous data regarding positive auto antibodies in CKV. Objective is to systematically evaluate the prevalence of auto antibodies in CKV patients. Methods. All study participants had clinical manifestations being CKV positive at least serologally or by RT-PCR data. The following autoantibodies were assessed: antinuclear antibodies (ANA), anti-dsDNA, anti-Sm, anti-Ro/SS-A, anti-La/SS-B, anti-U1RNP, IgG and IgM anticardiolipin, anticyclic citrullinated peptide (antiCCP), rheumatoid factor (RF), antiribosomal P protein, lupus anticoagulant, anti-Jo-1 and anti-Scl-70. CH100, C3 and C4 complement components, serum levels of immunoglobulins, C-reactive protein, erythrocyte sedimentation rate, alpha1-acid glycoprotein, antithyroglobulin, antithyroperoxidase, TRAb, 25 hydroxyvitamin D (25OHD), dengue and zika IgG and IgM antibodies were also measured. Results. 30 CKV patients were included. Mean age was 59.1±15.7 years, 85% females and 77% Caucasian subjects. Disease duration comprised 4.9±4.0 months. Oligoarthritis was observed in 93% cases. Mean C-reactive protein levels were 10.1±6.8 ng/dL, erythrocyte sedimentation rate — 34.2±19.9 mm/1st hour and alpha1-acid glycoprotein 115.5±52.6 mg/dL. Intramuscular betamethasone depot single dose injection was administered in 54%, prednisone — in 15% and methotrexate — in 23% cases. Importantly, 1/30 (3.3%) cases was positive for ANA, 4/30 (13.3%) — for RF and none was positive for anti-CCP or any other autoantibodies. Complement and immunoglobulin levels were all within the normal range. Low levels of 25OHD were observed in 88% cases.

Introduction. Global climate changes affect the habitats of insects, including mosquitoes, which are carriers of dangerous natural focal infections. When mosquitos develop new territories, they create a potential threat to people who find themselves in these areas. In the Krasnodar Region, a stable population of Ae. albopictus mosquitoes was formed in the 21st century. These mosquitoes are carriers of many viral pyrrhoid-focal infections, such as Dengue, Chikungunya, Zika fever and Yellow fever. Estimations of biological, epidemiological and cultural data can help to answer the question of the probability of occurrence of autochthonous cases of infection.Aim. To estimate the probability of occurrence of autochthonous cases of viral infections carried by Ae. albopictus mosquitoes on the territory of the Black Sea coast of the Krasnodar territory. For the review, we used scientific publications describing the occurrence of autochthonous diseases in similar climate zones inhabited by Ae. albopictus mosquitoes, the biology of these mosquitoes, as well as official reports of the sanitary services of Europe and the Russian Federation. A stable population of Ae. albopictus mosquitoes has formed on the Black Sea coast of the Krasnodar Territory. The local climate, including the temperature range is favourable for active reproduction of vectors and autochthonous transmission of viral infection.Conclusion. Despite the favourable conditions for the release of mosquitoes and the formation of a stable population, autochthonous transmission requires the introduction of the source of infection during the viremia period to infect the mosquito population. In recent years, isolated cases of such drifts have been reported in the Krasnodar Territory, which indicates a low probability of local cases of transmission. However, with the development of the tourism sector, the flow of tourists from endemic areas will inevitably increase. In addition, the increase in the well-being of the population, trips to these countries will become more frequent this may well increase the risk of transmission of viral infections by local mosquitoes. In any case, the weakening of epidemic control of mosquitoes and medical surveillance of imported cases of tropical fevers will have serious consequences.

The purpose of study was to isolate arboviruses from mosquitoes of different species in the cell culture and to identify them by using molecular and immunochemical techniques.Materials and methods. Viruses were isolated in C6/36 cell cultures. The pathogens were identified by using enzyme-linked immunosorbent assay (ELISA) kits for detection of antigens of dengue, Chikungunya, West Nile and Sindbis viruses as well as the reverse transcription polymerase chain reaction (RT-PCR) with specific primers and Sanger sequencing.Results. A total of 102 mosquitoes belonging to three genera, Culex spp, Culiseta spp., Aedes spp., were studied. Mosquitoes of each species or genus were divided into pools, each containing 4–5 mosquitoes. The study of suspensions of only 2 mosquito pools obtained from Aedes aegypti and Aedes albopictus, starting from the 3rd passage, showed changes in the C6/36 cell monolayer. Starting from the 4th passage, an antigen of Chikungunya virus was detected using ELISA test in the suspension obtained from the Aedes albopictus pool. Dengue virus was detected in the 5th passage from the materials obtained from the Aedes aegypti pool. Thus, antigens of the Chikungunya and dengue viruses were detected only in 2 of 23 examined pools of mosquitoes of different genera. Materials of the 5th passage were analyzed by RT-PCR with specific primers for dengue and Chikungunya viruses. It was confirmed that the isolate obtained from Aedes albopictus mosquitoes contained RNA of the Chikungunya virus and corresponded to the East/Central/South African genotype, while the isolate obtained from Aedes aegypti mosquitoes contained RNA of the dengue type 2 virus.Conclusion. The obtained nucleotide sequences of the Chikungunya virus were deposited in the GenBank international database under accession numbers MN271691 and MN271692.