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In 2007 (1) and 2017 (2), local outbreaks of human chikungunya infection occurred in Italy; both outbreaks were caused by the East/Central/South African strain of chikungunya virus (CHIKV). Both outbreaks [...]

Dengue (DENV) and Zika (ZIKV) viruses are mosquito-borne human pathogens. In Italy, the presence of the competent vector Aedes albopictus increases the risk of autochthonous transmission, and a national plan for arboviruses prevention, surveillance, and response (PNA 2020–2025) is in place. The results of laboratory diagnosis of both viruses by the National Reference Laboratory for arboviruses (NRLA) from November 2015 to November 2022 are presented. Samples from 655 suspected cases were tested by both molecular and serological assays. Virus and antibody kinetics, cross-reactivity, and diagnostic performance of IgM ELISA systems were analysed. Of 524 cases tested for DENV, 146 were classified as confirmed, 7 as probable, while 371 were excluded. Of 619 cases tested for ZIKV, 44 were classified as confirmed, while 492 were excluded. All cases were imported. Overall, 75.3% (110/146) of DENV and 50% (22/44) of ZIKV cases were confirmed through direct virus detection methods. High percentages of cross reactivity were observed between the two viruses. The median lag time from symptoms onset to sample collection was 7 days for both DENV molecular (range 0–20) and NS1 ELISA (range 0–48) tests, with high percentages of positivity also after 7 days (39% and 67%, respectively). For ZIKV, the median lag time was 5 days (range 0–22), with 16% positivity after 7 days. Diagnostic performance was assessed with negative predictive values ranging from 92% to 95% for the anti-DENV systems, and of 97% for the ZIKV one. Lower positive predictive values were seen in the tested population (DENV: 55% to 91%, ZIKV: 50%). DENV and ZIKV diagnosis by molecular test is the gold standard, but sample collection time is a limitation. Serological tests, including Plaque Reduction Neutralization Test, are thus necessary. Co-circulation and cross-reactivity between the two viruses increase diagnostic difficulty. Continuous evaluation of diagnostic strategies is essential to improve laboratory testing. [ABSTRACT FROM AUTHOR]

Background: On 11 March 2020, the World Health Organisation (WHO) declared the coronavirus disease 2019 (COVID-19) outbreak to be a pandemic. As the mosquito season progressed, the understandable concern that mosquitoes could transmit the virus began to increase among the general public and public health organisations. We have investigated the vector competence of Culex pipiens and Aedes albopictus, the two most common species of vector mosquitoes in Europe, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to the very unusual feeding behaviour of Ae. albopictus, we also evaluated the role of this mosquito in a potential mechanical transmission of the virus. Methods: For the vector competence study, mosquitoes were allowed to take several infectious blood meals. The mosquitoes were then collected and analysed at 0, 3, 7 and 10 days post-feeding. For the mechanical transmission test, Ae. albopictus females were allowed to feed for a short time on a feeder containing infectious blood and then on a feeder containing virus-free blood. Both mosquitoes and blood were tested for viral presence. Results: Culex pipiens and Ae. albopictus were found not be competent vectors for SARS-CoV-2, and Ae. albopictus was unable to mechanically transmit the virus. Conclusions: This is the first study to show that the most common species of vector mosquitoes in Europe do not transmit SARS-CoV-2 and that Ae. albopictus is unable to mechanically transmit the virus from a positive host to a healthy host through host-feeding. [ABSTRACT FROM AUTHOR]

Background: A CD4+CD25- regulatory T cell population expressing the surface TGF-β in its latent form LAP+ [latency associated peptide] cells was proved to be protective in experimental colitis and to be suppressive of human peripheral blood [PB] T proliferation. We investigated the frequency and function of lamina propria [LP] CD4+LAP+ T cells in inflammatory bowel disease [IBD] patients. Methods: Specimens from patients undergoing colonoscopy or bowel resection for IBD and colonic cancer were used as source of lamina propria mononuclear cells [LPMC]. The ulcerative colitis [UC] group was divided according to endoscopic activity evaluated with modified Baron Score. IL-17, IFN-γ, IL-10, LAP, and Foxp3 expression in CD3+CD8- [CD4] or CD3+/CD4+ gated cell population was assessed by immunofluorescence. The ability of FACS-sorted LP CD3+CD8-[CD4] LAP+CD25- to inhibit stimulated autologous PB CD3+CD8-[CD4] LAP- CD25- cells proliferation was assessed. Results: LP CD4LAP+ cells were significantly increased, when compared with controls, in active UC patients and not in Crohn's disease patients. The majority of LP CD4+LAP+ cells were Foxp3-. The percentage of IL-17+ cells in LP CD3+CD8-[CD4] LAP+ cells was significantly higher in active UC patients when compared with controls. LP CD3+CD8-[CD4]LAP+CD25- isolated from UC patients showed reduced or no ability to inhibit autologous PB CD3+CD8-[CD4]LAP-CD25- cell proliferation when compared with controls. Removal of IL-17+ cells from LP CD3+CD8-[CD4] LAP+ cells increases their suppressive ability. Conclusions: The percentage of LP CD4LAP+ cells is increased in active UC, showing reduced suppressor activity due to their increased proportion of intracellular IL-17 expression. [ABSTRACT FROM AUTHOR]

Background Chikungunya virus is an emerging mosquito-borne pathogen with a wide global distribution. With the severe morbidity that it causes, chikungunya virus is a major public health problem in the affected areas and poses a considerable risk for unaffected areas hosting competent vector populations. In the summer of 2017, Italy experienced a chikungunya virus outbreak that spread in the Lazio region and caused a secondary outbreak in the Calabrian village of Guardavalle, with a final case number of 436. The causative strain was recognized as an Indian Ocean lineage (IOL) virus. Methods To understand the underlying genetic and molecular features of the outbreak virus, viruses from mosquito pools and clinical samples were isolated in cell culture and subjected to whole-genome sequencing and genetic analyses. Results All 8 characterized genomes shared a high sequence identity. A distinct substitution pattern in the Italian 2017 viruses (including mutations in E1, E2, and nsP4) was partly shared with the Pakistani 2016 outbreak viruses. Evolutionary analyses indicate that these 2 recent outbreaks and several geographically widely distributed, travel-associated viruses form a cluster of rapidly emerging Indian-origin IOL viruses. Conclusions Our analyses show that the 2017 Italian outbreak virus belongs to a cluster of novel IOL chikungunya viruses originating in India. Their emergence calls for enhanced monitoring and strengthened preparedness measures, including vector control programs and raised awareness among general practitioners in countries potentially at risk. [ABSTRACT FROM AUTHOR]