West Nile Virus Neuroinvasive Disease (WNV NID) requires prolonged intensive care treatment, resulting in high mortality and early disability. Long-term results are lacking. We have conducted an observational retrospective study with a prospective follow-up of WNV NID patients treated at the Intensive Care Unit (ICU), University Hospital for Infectious Diseases, Zagreb, Croatia, 2013–2018. Short-term outcomes were vital status, length of stay (LOS), modified Rankin Scale (mRS), and disposition at discharge. Long-term outcomes were vital status and mRS at follow-up. Twenty-three patients were identified, 78.3% males, median age 72 (range 33–84) years. Two patients (8.7%) died in the ICU, with no lethal outcomes after ICU discharge. The median ICU LOS was 19 days (range 5–73), and the median hospital LOS was 34 days (range 7–97). At discharge, 15 (65.2%) patients had moderate to severe/mRS 3–5, 6 (26.0%) had slight disability/mRS 2–1, no patients were symptom-free/mRS 0. Ten (47.6%) survivors were discharged to rehabilitation facilities. The median time to follow-up was nine months (range 6–69). At follow-up, seven patients died (30.5%), five (21.7%) had moderate to severe/mRS 3–5, one (4.3%) had slight disability/mRS 2–1, six (26.1%) had no symptoms/mRS 0, and four (17.4%) were lost to follow-up. Briefly, ten (43.5%) survivors improved their functional status, one (4.3%) was unaltered, and one (4.3%) aggravated. In patients with severe WNV NID, intensive treatment in the acute phase followed by inpatient rehabilitation resulted in significant recovery of functional status after several months.

Data on the immune response to West Nile virus (WNV) are limited. We analyzed the antiviral cytokine response in serum and cerebrospinal fluid (CSF) samples of patients with WNV fever and WNV neuroinvasive disease using a multiplex bead-based assay for the simultaneous quantification of 13 human cytokines. The panel included cytokines associated with innate and early pro-inflammatory immune responses (TNF-α/IL-6), Th1 (IL-2/IFN-γ), Th2 (IL-4/IL-5/IL-9/IL-13), Th17 immune response (IL-17A/IL-17F/IL-21/IL-22) and the key anti-inflammatory cytokine IL-10. Elevated levels of IFN-γ were detected in 71.7% of CSF and 22.7% of serum samples (p = 0.003). Expression of IL-2/IL-4/TNF-α and Th1 17 cytokines (IL-17A/IL-17F/IL-21) was detected in the serum but not in the CSF (except one positive CSF sample for IL-17F/IL-4). While IL-6 levels were markedly higher in the CSF compared to serum (CSF median 2036.71, IQR 213.82–6190.50; serum median 24.48, IQR 11.93–49.81; p < 0.001), no difference in the IL-13/IL-9/IL-10/IFN-γ/IL-22 levels in serum/CSF was found. In conclusion, increased concentrations of the key cytokines associated with innate and early acute phase responses (IL-6) and Th1 type immune responses (IFN-γ) were found in the CNS of patients with WNV infection. In contrast, expression of the key T-cell growth factor IL-2, Th17 cytokines, a Th2 cytokine IL-4 and the proinflammatory cytokine TNF-α appear to be concentrated mainly in the periphery.

Semaphorins are a diverse family of immunoregulators recently recognized to play a major role in various phases of immune responses. Their role in chronic viral hepatitis C (CHC) and contribution to the progression of liver disease is unknown. The aim of this study was to analyse the association of secreted semaphorins with the severity of liver disease in patients with CHC. Serum concentrations of semaphorins were measured in 114 treatment-naive CHC patients and 36 healthy controls. Serum concentrations of SEMA3A, SEMA3C, SEMA5A, SEMA6B and SEMA6D were significantly increased in patients with CHC compared to controls. While serum concentrations of SEMA3C and SEMA6D significantly increased with fibrosis stage in both HCV-g1 and HCV-g3 infections, the concentration of SEMA5A inversely correlated with fibrosis stage in both HCV genotypes. ROC analysis showed that serum concentrations of SEMA3C (>4.0ng/mL, AUC 0.88) and SEMA6D (>4.5, AUC 0.82) had higher AUC than widely used APRI (AUC 0.71) and FIB-4 (AUC 0.74) scores. Serum concentrations of SEMA3C and SEMA6D significantly decreased after DAA and PEG IFN-α/ribavirin therapy, while the serum concentration of SEMA5A significantly increased after DAAs therapy. Immunohistochemistry confirmed the expression of SEMA3C and SEMA5A in hepatocytes, endothelial cells and lymphocytes of cirrhotic livers from CHC patients but not in controls. In conclusion, we provide the first evidence that SEMA3C, SEMA5A and SEMA6D can be considered as markers of liver injury in CHC.

Toscana virus (TOSV) is an arthropod-borne virus, transmitted to humans by phlebotomine sandflies. Although the majority of infections are asymptomatic, neuroinvasive disease may occur. We report three cases of neuroinvasive TOSV infection detected in Croatia. Two patients aged 21 and 54 years presented with meningitis, while a 22-year old patient presented with meningoencephalitis and right-sided brachial plexitis. Cerebrospinal fluid (CSF), serum, and urine samples were collected and tested for neuroinvasive arboviruses: tick-borne encephalitis, West Nile, Usutu, TOSV, Tahyna, and Bhanja virus. In addition, CSF and serum samples were tested for the anti-viral cytokine response. High titers of TOSV IgM (1000–3200) and IgG (3200−10,000) antibodies in serum samples confirmed TOSV infection. Antibodies to other phleboviruses (sandfly fever Sicilian/Naples/Cyprus virus) were negative. CSF samples showed high concentrations of interleukin 6 (IL-6; range 162.32−2683.90 pg/mL), interferon gamma (IFN-γ; range 110.12−1568.07 pg/mL), and IL-10 (range 28.08−858.91 pg/mL), while significantly lower cytokine production was observed in serum. Two patients recovered fully. The patient with a brachial plexitis improved significantly at discharge. The presented cases highlight the need of increasing awareness of a TOSV as a possible cause of aseptic meningitis/meningoencephalitis during summer months. Association of TOSV and brachial plexitis with long-term sequelae detected in one patient indicates the possibility of more severe disease, even in young patients.

We assessed the feasibility of collecting urine samples for testing on genital Chlamydia trachomatis infection in a population-based survey, and prevalence of this infection among young people aged 18-25 in Croatia. In Croatia, as in the other countries of Eastern Europe, there is a lack of data on prevalence of C trachomatis in the general population, including young adults.

Human cytomegalovirus (HCMV) is a pathogen with high prevalence in the general population that is responsible for high morbidity and mortality in immunocompromised individuals and newborns, while remaining mainly asymptomatic in healthy individuals. The HCMV genome is 236,000 nucleotides long and encodes approximately 200 genes in more than 170 open reading frames, with the highest rate of genetic polymorphisms occurring in the envelope glycoproteins. HCMV infection is treated with antiviral drugs such as ganciclovir, valganciclovir, cidofovir, foscarnet, letermovir and maribavir targeting viral enzymes, DNA polymerase, kinase and the terminase complex. One of the obstacles to successful therapy is the emergence of drug resistance, which can be tested phenotypically or by genotyping using Sanger sequencing, which is a widely available but less sensitive method, or next-generation sequencing performed in samples with a lower viral load to detect minority variants, those representing approximately 1% of the population. The prevalence of drug resistance depends on the population tested, as well as the drug, and ranges from no mutations detected to up to almost 50%. A high prevalence of resistance emphasizes the importance of testing the patient whenever resistance is suspected, which requires the development of more sensitive and rapid tests while also highlighting the need for alternative therapeutic targets, strategies and the development of an effective vaccine.