The First Imported Case of Chikungunya Virus Infection - Anhui Province, China, 2025.

Risk for Emergence of Dengue and Chikungunya Virus in Israel

We compared the morbidity and quality of life of military policemen ("gendarmes") infected with chikungunya virus (CHIKV+) 30 months after contamination. We categorized the subjects in 3 groups: healed patients (n = 48), non-healed patients (n = 37, 44% of CHIKV+), and uninfected subjects (CHIKV-, n = 297). Data were self-recorded in this retrospective cohort study; they included sociodemographic information, clinical symptoms, and the Medical Outcome Study 36-item short-form health survey (MOS-SF36) quality of life questionnaire. The study population was mostly men (92%), with a median age of 42.8 years, regardless of CHIKV status. The main complaints were rheumatic symptoms (pain, stiffness, and swelling), reported 5 times more often by non-healed CHIKV+ subjects and 2-3 times more often by healed CHIKV+ subjects than by CHIKV- subjects, and fatigue. The CHIKV+ patients reported more use of health care services. Thirty months after infection, all rheumatic symptoms were more frequent and intense among CHIKV+ than among CHIKV- subjects, with a gradient of severity between healed and non-healed CHIKV+ subjects. Non-healed CHIKV+ subjects reported subsequent limitation in their activities. All dimensions of MOS-SF36 as well as physical and mental component summaries were impaired in CHIKV+ compared to CHIKV- subjects, with a decreasing gradient of impairment from non-healed to healed CHIKV+ subjects, then to CHIKV- subjects. These observations confirm the long-term impact of CHIKV infection on both physical and mental health. Questions persist regarding the duration of this impairment and the possibility of a return to "before CHIKV" health status for infected patients.

Chikungunya virus (CHIKV) is a mosquito borne alphavirus, whose primary disease manifestation in humans is acute and chronic, often debilitating polyarthritis/polyathralgia. Current treatments are often inadequate. This thesis aims to elucidate the roles of several immune components in CHIKV disease, using a mouse model of CHIKV infection and disease, which recapitulates many aspects of human disease. An improved understanding of the immunobiology of CHIKV is required for future development of new interventions for this recently re-emergent virus. CHIKV polyarthritis/polyathralgia is associated with a prolific monocytes/macrophage infiltration of musculoskeletal tissue in humans, monkeys and mice. The infection in all species is associated with high levels of chemokine (C-C motif) ligand 2 (CCL2), a chemokine that binds chemokine (C-C motif) receptor 2 (CCR2) and is involved in recruitment of monocytes to the sites of infection. Targeting CCL2 or CCR2 signalling has thus been proposed as a potential treatment option for CHIKV disease. Results herein show that CHIKV infection of mice deficient in CCR2 led to a significantly more pronounced and prolonged arthritis that was associated with cartilage damage. The prominent monocytes/macrophages infiltrate seen in wild-type mice was replaced by a prolific neutrophil infiltrate in CCR2-/- mice. The switch in the arthritic infiltrate was associated with changes in the expression of multiple inflammatory mediators, with the loss of anti- inflammatory macrophages and their activities (e.g. efferocytosis) also implicated in the exacerbated inflammatory response. These results illustrated that the recruited monocytes/macrophages in wild-type mice (although associated with acute disease) also have a protective role in CHIKV arthritis. These results suggest caution may be warranted when considering therapeutic targeting of CCR2 for treatment of CHIKV arthritis (Chapter 3). To study the role of different components of the immune system in CHIKV viraemia and disease, mice deficient in B cells, T cells, CD4+ T cells, natural killer cells and IFN-g were infected with CHIKV. Results herein confirmed that B cells are crucial for controlling CHIKV viraemia, but showed that T cells also play a role, albeit secondary to antibodies. B cell deficient mice experienced a life long viraemia with little overt pathology evident, supporting the view that CHIKV disease is largely an immunopathology. In T and B cell deficient mice, viraemia was likely controlled by chronic up-regulation of tumour necrosis factor and interferon gamma, but not interferon alpha/beta. Importantly, CD4+ T cells and interferon gamma were shown to play important roles in acute CHIKV arthritis, with T cells previously thought not to play a significant role (Chapter 4). CHIKV disease in humans is often associated with chronic arthritic symptoms that persist for months, occasionally over a year, after CHIKV infection. Persistence of CHIKV has been postulated to be responsible for the chronic arthritis. To further investigate this issue, chronic infection and disease parameters were analysed in the established wild-type mouse model of acute CHIKV arthritis. Viraemia is cleared day 4-5 post-infection and neutralising antibodies are detected as early as day 4 post-infection, and rose significantly thereafter. Despite the high levels of neutralising antibodies, replication competent CHIKV could be recovered from feet of infected mice up to day 14 post-infection. Importantly, significant levels of CHIKV RNA (including negative strand RNA) could be detected by quantitative real-time polymerase chain reaction in feet up to day 100 post-infection. Interferon stimulated gene 54, a factor that is up-regulated in response to viral infection and double stranded RNA, was found also to be persistently up-regulated in these feet, suggesting ongoing replication of viral RNA. Microarray analysis of these feet revealed that (i) many of the pathways up-regulated during acute arthritis were maintained during chronic infection, (ii) on-going local inflammatory responses were dominated by type I IFN responses, and (iii) many of the inflammatory pathways identified in chronically infected mouse feet were also found in chronic CHIKV patients. These observations suggest that chronic disease is due to ongoing inflammation stimulated by persistently replicating viral RNA and viral proteins encoded by that RNA (Chapter 5). In conclusion, this thesis has shown, that inflammatory CCR2+ monocyte can be critical for preventing excessive pathology and resolving inflammation, that distinct immune factors control CHIKV viraemia and arthritis, and that long-term persistence of replicating CHIKV RNA might be the cause of protracted arthritic manifestations in CHIKV patients. These studies will hopefully inform future development of intervention for CHIKV.

Chikungunya virus: An emerging public health challenge for Pakistan

Yellow fever (YF), Chikungunya (CHIK), and Zika(ZIK) are among re-emerging arboviral diseases of major public health concern. Despite the proximity of the Gambella Region to South Sudan where arboviral cases have been recorded repeatedly the current epidemiological situation is unclear in this part of southwest Ethiopia. Therefore, we conducted a community-based seroprevalence survey of YF virus (YFV), CHIK virus (CHIKV), and ZIK virus (ZIKV) infections in two selected districts. A cross-sectional study was conducted in two locations of the Gambella region (Lare and Itang) to investigate the seroprevalence of these viruses’ infections. Blood samples were collected from the study participants and screened for IgG antibodies specific to YFV and CHIKV infections using enzyme-linked immunosorbent assays (ELISA). For the detection of ZIKV specific IgG antibodies, Blockade-of-binding ELISA was used. Data were analyzed using the STATA version 13.1 Softwares. A total of 150 individuals (96 males and 54 females, age ranging from 18 to 65 years, mean age ± SD = 35.92 ± 10.99) participated and provided blood samples. Among the 150 samples 135, 90, and 150 were screened for YFV, CHIKV, and ZIKV, respectively. Hence, 2.9% (95% CI: 1.1–7.7%), 15.6% (95% CI: 9.3–24.8%), and 27.3% (95% CI: 20.7–35.3%) of samples tested positive for IgG antibodies to YFV, CHIKV, and ZIKV infections, respectively. Among the individual seropositive for ZIKV, YFV and CHIKV, only six, one and three had a history of residence outside the Gambella region respectively. Agro-pastoral occupation was significantly associated with a higher prevalence of IgG against CHIKV (AOR = 14.17; 95%CI: 2.30, 87.30) and residency in the Lare district (AOR = 11; 95%CI: 3.31, 39.81) was found to be significantly associated with a higher prevalence of IgG against ZIKV. Our findings revealed the occurrence of YFV, CHIKV and ZIKV infections in the study locations.

First cases of autochthonous dengue fever and chikungunya fever in France: from bad dream to reality!

Atypical Chikungunya Virus Infections in Immunocompromised Patients

Limited information is available on the seroprevalence of chikungunya virus (CHIKV) infection and maternal-fetal transmission incidence of CHIKV and dengue virus (DENV) infections during the 2008-2009 CHIKV outbreak in southern Thailand. A community-based post-epidemic seroprevalence study was conducted in parturient women admitted to the Thepa District Hospital in Songkhla Province, Thailand, for delivery from November 2009 to May 2010. The women were tested for chikungunya (CHIK) IgM/IgG and dengue (DEN) IgM/IgG. Cord blood samples were also tested for CHIK IgM or DEN IgM in women who tested positive for CHIK IgM or DEN IgM, respectively. The seroprevalence of CHIKV infection (CHIK IgM or IgG positive) was 227/319 (71·2%) with pre-outbreak seroprevalence (IgM-/IgG+) of 43·6% and the seroprevalence of DENV infection was 288/319 (90·3%). Complications during pregnancy, newborn outcomes and congenital anomalies were not different in those who had recent, remote or no CHIKV infections. None of the newborns whose mothers were CHIK or DEN IgM positive had cord blood positive for both CHIK and DEN IgM. In conclusion, both CHIKV and DENV are endemic in southern Thailand; during the recent CHIKV outbreak CHIK seroprevalence increased from 43·6% to 71·2%.

Chikungunya virus (CHIKV), a re-emerging infectious arbovirus, causes Chikungunya fever that is characterized by fever, skin rash, joint pain, arthralgia and occasionally death. Despite it has been described for 66 years already, neither potential vaccine nor a specific drug is available yet. During CHIKV infection, interferon type I signaling pathway is stimulated and releases hundreds of interferon stimulated genes (ISGs). Our previous study reported that IFI16, a member of ISGs, is up-regulated during CHIKV virus infection and the suppression of the gene resulted in increased virus replication. Furthermore, our group also found that inflammasome activation can inhibit CHIKV infection in human foreskin cells (HFF1). Concomitantly, it has been reported that IFI16 activates the inflammasome to suppress virus infection. Therefore, we have hypothesized that IFI16 could be involved in CHIKV infection. In this study, we confirmed the expression level of IFI16 by Western blotting analysis and found that IFI16 was up-regulated following CHIKV infection in both HFF1 and human embryonic kidney cells. We next investigated its antiviral activity and found that forced expression of IFI16 completely restricted CHIKV infection while endogenous silencing of the gene markedly increased virus replication. Furthermore, we have discovered that IFI16 inhibited CHIKV replication, at least, in cell-to-cell transmission as well as the diffusion step. Interestingly, IFI16 also exerted its antiviral activity against Zika virus (ZIKV) infection, the global threat re-emerging virus can cause microcephaly in humans. Taken together, this study provides the first evidence of an antivirus activity of IFI16 during in vitro arbovirus infection, thus expanding its antiviral spectrum that paves the way to further development of antiviral drugs and vaccines.

Chikungunya virus (CHIKV) infection is endemic in many different countries. CHIKV outbreaks are emerging in new areas and re-emerging in previously exposed geographical regions, thus making it a significant public health concern. CHIKV infections are often clinically inapparent, especially in children, which poses a challenge to testing and evaluating any vaccine. During CHIKV infection, CHIKV-specific antibodies are produced, and some of these antibodies can neutralize viruses released from infected cells before they can enter uninfected cells. In this study, we evaluated IgG binding and neutralizing antibody responses in paired serum samples from CHIKV-infected children and those with other febrile illness, using a recombinant truncated E2 protein and whole CHIKV particles as test antigens. Antibody detection using the truncated E2 protein showed a significant overlap between CHIKV-infected subjects and those with other febrile illnesses. This overlap was greater when binding antibody titers were determined using fixed CHIKV particles as the test antigen. Acute- and convalescent-phase sera collected from children after CHIKV infection showed significant differences in their neutralizing capacity. The neutralizing and binding antibody response showed a significant positive correlation. We detected IgG antibodies in most cases during the acute phase of infection. This was observed at two different geographical locations, one of which is not considered highly endemic. Conventional wisdom would suggest this to be a marker of re-infection (secondary infection). However, dissenting opinions have been voiced in other viral diseases (such as Ebola) where studies have detected IgG in acute illness. In the absence of any significant body of work documenting secondary CHIKV infections, we believe further work is needed to understand the early IgG response that we observed.

Local transmission of Chikungunya virus (CHIKV) was first documented in Trinidad and Tobago (T&T) in July 2014 preceding a large epidemic. At initial presentation, it is difficult to distinguish chikungunya fever (CHIKF) from other acute undifferentiated febrile illnesses (AUFIs), including life-threatening dengue disease. We characterised and compared dengue virus (DENV) and CHIKV infections in 158 patients presenting with suspected dengue fever (DF) and CHIKF at a major hospital in T&T, and performed phylogenetic analyses on CHIKV genomic sequences recovered from 8 individuals. The characteristics of patients with and without PCR-confirmed CHIKV were compared using Pearson’s χ2 and student’s t-tests, and adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were determined using logistic regression. We then compared signs and symptoms of people with RT-qPCR-confirmed CHIKV and DENV infections using the Mann-Whitney U, Pearson’s χ2 and Fisher’s exact tests. Among the 158 persons there were 8 (6%) RT-qPCR-confirmed DENV and 30 (22%) RT-qPCR-confirmed CHIKV infections. Phylogenetic analyses showed that the CHIKV strains belonged to the Asian genotype and were most closely related to a British Virgin Islands strain isolated at the beginning of the 2013/14 outbreak in the Americas. Compared to persons who were RT-qPCR-negative for CHIKV, RT-qPCR-positive individuals were significantly more likely to have joint pain (aOR: 4.52 [95% CI: 1.28–16.00]), less likely to be interviewed at a later stage of illness (days post onset of fever—aOR: 0.56 [0.40–0.78]) and had a lower white blood cell count (aOR: 0.83 [0.71–0.96]). Among the 38 patients with RT-qPCR-confirmed CHIKV or DENV, there were no significant differences in symptomatic presentation. However when individuals with serological evidence of recent DENV or CHIKV infection were included in the analyses, there were key differences in clinical presentation between CHIKF and other AUFIs including DF, which can be used to triage patients for appropriate care in the clinical setting.

Objective To develop a convenient, rapid and specific method using real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) for detection of facioscapulohumeral muscular dystrophy(FSHD). Methods Genomic DNA was extracted and digested by restricted endonuclease EcoR Ⅰ , followed by agarose electrophoresis. The DNA (< 38 kb) was retrieved from agarose electrophoretic gels. The primers and probe were designed in D4ZA gene in chromosome 4. One hundred and fifteen subjects were examined by FQ-PCR using the retrieved DNA (<38 kb) as a template and the result was analyzed by fluorescent curve comparing with positive control. Results The results by FQ-PCR showed that 13 cases were positive in 16 FSHD cases whose EcoR Ⅰ fragment sizes were known, 75 cases were negative in 78 cases of normal controls, 15 cases were positive in 16 FSHD cases diagnosed clinically whose EcoR Ⅰ fragment sizes were unknown, and 3 cases were positive in 5 cases of relatives of FSHD patients. Consistency was checked using Kappa index between the 2 gene diagnostic tests for FSHD (FQ-PCR test and the traditional Southern blotting test), and between the 2 diagnostic criterions (gene diagnosis by FQ-PCR and clinical diagnosis). The results were statistically significant (κ = 0. 765, P = 0. 002 ; κ = 0. 844, P = 0. 000). Conclusions A new genetic diagnostic method of FSHD by FQ-PCR was developed, which was more simplified and reliable compared to the time-consuming, radioactive Southern blotting. It could also detect the D4Z4 arrays in cases having deletion of p13E-11 as well as the interchromosomal exchange between 4q35 and 10q26. The new method of FQ-PCR for FSHD may be extended to utilize clinically in future. Key words: Muscular dystrophy; facioscapulohumeral; Polymerase chain reaction; Translocation; genetic

Chikungunya virus (CHIKV) infection causes intense cytokine/chemokine inflammatory responses and debilitating joint pain. Indoleamine2,3–dioxygenase 1 (IDO-1) is an enzyme that initiates the tryptophan degradation that is important in initial host innate immune defense against infectious pathogens. Besides that, IDO-1 activation acts as a regulatory mechanism to prevent overactive host immune responses. In this study, we evaluated IDO-1 activity and cytokine/chemokine patterns in CHIKV patients. Higher IDO-1 (Kyn/Trp ratio) activation was observed during the early acute phase of CHIKV infection and declined in the chronic phase. Importantly, increased concentrations of Tumor Necrosis Factor-α (TNF-α), Interleukin-6 (IL-6), Interferon γ (IFN-γ), C-C motif chemokine ligand 2/Monocyte Chemoattractant Protein-1 (CCL2/MCP-1) and C-X-C motif chemokine ligand 10/Interferon Protein-10 (CXCL10/IP-10) were found in the acute phase of infection, while C-C motif chemokine ligand 4/Macrophage Inflammatory Protein 1 β (CCL4/MIP-1β) was found at increased concentrations in the chronic phase. Likewise, CHIKV patients with arthritis had significantly higher concentrations of CCL4/MIP-1β compared to patients without arthritis. Taken together, these data demonstrated increased IDO-1 activity, possibly exerting both antiviral effects and regulating exacerbated inflammatory responses. CCL4/MIP-1β may have an important role in the persistent inflammation and arthritic symptoms following chikungunya infection.

University of São Paulo. School of Medicine. São Paulo, SP, Brazil / Emílio Ribas Institute of Infectious Diseases. São Paulo, SP, Brazil.

Chikungunya virus (CHIKV) infections can cause severe and debilitating joint and muscular pain that can be long lasting. Current CHIKV vaccines under development rely on the generation of neutralizing antibodies for protection; however, the role of T cells in controlling CHIKV infection and disease is still unclear. Using an overlapping peptide library, we identified the CHIKV-specific T cell receptor epitopes recognized in C57BL/6 infected mice at 7 and 14 days post-infection. A fusion protein containing peptides 451, 416, a small region of nsP4, peptide 47, and an HA tag (CHKVf5) was expressed using adenovirus and cytomegalovirus-vectored vaccines. Mice vaccinated with CHKVf5 elicited robust T cell responses to higher levels than normally observed following CHIKV infection, but the vaccine vectors did not elicit neutralizing antibodies. CHKVf5-vaccinated mice had significantly reduced infectious viral load when challenged by intramuscular CHIKV injection. Depletion of both CD4+ and CD8+ T cells in vaccinated mice rendered them fully susceptible to intramuscular CHIKV challenge. Depletion of CD8+ T cells alone reduced vaccine efficacy, albeit to a lesser extent, but depletion of only CD4+ T cells did not reverse the protective phenotype. These data demonstrated a protective role for CD8+ T cells in CHIKV infection. However, CHKVf5-vaccinated mice that were challenged by footpad inoculation demonstrated equal viral loads and increased footpad swelling at 3 dpi, which we attributed to the presence of CD4 T cell receptor epitopes present in the vaccine. Indeed, vaccination of mice with vectors expressing only CHIKV-specific CD8+ T cell epitopes followed by CHIKV challenge in the footpad prevented footpad swelling and reduced proinflammatory cytokine and chemokines associated with disease, indicating that CHIKV-specific CD8+ T cells prevent CHIKV disease. These results also indicate that a T cell-biased prophylactic vaccination approach is effective against CHIKV challenge and reduces CHIKV-induced disease in mice.