Chikungunya virus: An emerging public health challenge for Pakistan

Risk for Emergence of Dengue and Chikungunya Virus in Israel

Introduction: Dengue and Chikungunya have re-emerged as important diseases of global concern. Co-infections with Dengue virus (DENV) and Chikungunya virus (CHIKV) could have serious outcomes if not diagnosed and managed optimally. However, the key focal points for the maintenance of CHIKV and DENV infections and the extent of their co-infection remain poorly understood in many geo-ecologically distinct parts of Tanzania. Objective: We aimed to comparatively examine the prevalence and factors for seropositivity to DENV and CHIKV and their infection rates in humans and mosquitoes Methods: A cross-sectional study was performed in the Lower Moshi area of the Kilimanjaro region from April to July 2020. DENV and CHIKV exposure was determined by detecting IgM to the viruses using enzyme linked immunosorbent assay whereas infection was determined by real time quantitative polymerase chain reaction (RT-qPCR) assay. Results: Insecticide Treated Bed Net (ITN) use (χ2=3.504; p< 0.05), being ≥7 individuals living in the same household (χ2=4.655; p<0.05) and a recent travel to an urban destination (χ2=3.39; p< 0.05) were the only factors associated with CHIKV seropositivity. ITN use was the only factor associated with CHIKV infection (χ2=5.204; p<0.05). A recent travel to an urban destination (χ2=4.401; p< 0.05) was the only factor associated with DENV seropositivity. Five (1.5%) Ae. aegypti pools were positive for CHIKV whereas 1 (0.3%) was positive for DENV. Two Cx. pipiens, pools (1.9%) were positive for CHIKV. None of the Cx. pipiens mosquitoes was positive for DENV. No associations between DENV and CHIKV seropositivity was observed in humans but DENV infection was strongly associated with CHIKV infection (χ2 = 238.45; p<0.01). CHIKV infection was observed to be consistently higher in both, humans and mosquitoes. Conclusion: Detection of DENV and CHIKV in both humans and vector mosquitoes confirms that both viruses are actively circulating in the Lower Moshi area of Kilimanjaro region in Tanzania. Our findings point out the Lower Moshi area as a potential focal point for the maintenance of the two viruses and possibly other vector borne viruses. We call upon sustained active surveillance of arboviruses and other re-emerging infections to be better prepared for possible outbreaks by the viruses.

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%.

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

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.

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

The Dengue virus (DENV) and Chikungunya virus (CHIKV) are the arboviruses that pose a threat to global public health. Coinfection and antibody-dependent enhancement are major areas of concern during DENV and CHIKV infections, which can alter the clinical severity. Acute hepatic illness is a common manifestation and major sign of disease severity upon infection with either dengue or chikungunya. Hence, in this study, we characterized the coexistence and interaction between both the viruses in human hepatic (Huh7) cells during the coinfection/superinfection scenario. We observed that prior presence of or subsequent superinfection with DENV enhanced CHIKV replication. However, prior CHIKV infection negatively affected DENV. In comparison to monoinfection, coinfection with both DENV and CHIKV resulted in lower infectivity as compared to monoinfections with modest suppression of CHIKV but dramatic suppression of DENV replication. Subsequent investigations revealed that subneutralizing levels of DENV or CHIKV anti-sera can respectively promote the ADE of CHIKV or DENV infection in FcγRII bearing human myelogenous leukemia cell line K562. Our observations suggest that CHIKV has a fitness advantage over DENV in hepatic cells and prior DENV infection may enhance CHIKV disease severity if the patient subsequently contracts CHIKV. This study highlights the natural possibility of dengue–chikungunya coinfection and their subsequent modulation in human hepatic cells. These observations have important implications in regions where both viruses are prevalent and calls for proper management of DENV-CHIKV coinfected patients.

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.

Atypical Chikungunya Virus Infections in Immunocompromised Patients

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.

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.

BackgroundDengue and chikungunya are arboviral diseases with overlapping clinical characteristics. Dengue virus (DENV) is endemic in Colombia, and in 2014/2015, the chikungunya virus (CHIKV) caused an epidemic that resulted in over 350,000 cases. Since then, both viruses have been actively co-circulating. The early and accurate identification of pediatric infection caused by DENV or CHIKV is essential for proper medical management. Given that subsequent infections and co-infections with DENV and CHIKV have been reported, virological and immunological factors may influence their clinical outcomes. Here, we analyzed the viremia, antigenemia, and virus-specific antibody responses in hospitalized children suspected of having dengue during the peak of CHIKV infections in Colombia.MethodsNinety-one children with a clinical diagnosis of dengue were included in the peak of the CHIKV epidemic (December 2014 to May 2015) at a reference healthcare center in Huila, south of Colombia. Multiplexed RT-qPCR for DENV, CHIKV, and ZIKV was performed, and DENV antigenemia was evaluated using an ELISA for the NS1 antigen. Commercial capture or in-house indirect NS1-based ELISAs were used to assess circulating DENV and CHIKV-IgM and IgG. Clinical and laboratory characteristics were analyzed during hospitalization, and convalescent follow-up was conducted for a fraction of children.ResultsDENV and CHIKV monoinfections were confirmed in 54% and 12% of children, respectively, with the expected virus-specific seroconversion in recovery. Overlapping infections occurred in 22% of the children, while 12% showed no detectable DENV or CHIKV infections. Abdominal pain, vomiting, hepatomegaly, and thrombocytopenia were common findings associated with DENV, while arthralgia and rash characterized CHIKV monoinfections. One fatal secondary DENV-3 monoinfection was registered, and DENV infection dominated the symptoms of overlapping infections without producing different clinical outcomes compared to monoinfections. Thirty-eight percent of children were seropositive for CHIKV-IgG, indicating a significant burden of CHIKV infection in the pediatric population shortly after its introduction in Colombia. The previous virus-specific IgG serostatus did not impact the clinical outcome of the current heterotypic arboviral infection.ConclusionThe pediatric population in southern Colombia was rapidly exposed to CHIKV infections during the first months following its arrival, with up to 12% of hospitalized children suspected of having dengue experiencing CHIKV monoinfection, supporting that complex and dynamic epidemiological patterns may lead to delayed or missed diagnoses. The overlapping infections of DENV and CHIKV were frequent and did not lead to worse clinical or fatal outcomes.

To characterize the distribution profile of dengue, chikungunya, and Zika virus infections in Latin America and the Caribbean and to identify possible factors associated with the risk of dissemination and severity of these arboviruses. The protocol of this review was registered on the PROSPERO platform. Searches were carried out in the following databases: Virtual Health Library, MEDLINE/PubMed, and Embase. The search terms were: Zika virus, Zika virus infection, dengue, dengue virus, chikungunya virus, chikungunya fever, epidemiology, observational study, Latin America, and Caribbean region. Studies that addressed the distribution of these arboviruses and the risk factors associated with dengue, Zika virus disease, and chikungunya, published between January 2000 and August 2020 in English, Portuguese, and Spanish, were included. Of 95 studies included, 70 identified risk factors, clinical manifestations, and outcomes for arbovirus infections and 25 described complications and/or deaths. The highest frequency of confirmed cases was for dengue. Brazil reported most cases of the three arboviruses in the period analyzed. Environmental and socioeconomic factors facilitated the proliferation and adaptation of vectors, and host-related factors were reported to aggravate dengue. Most deaths were due to chikungunya, Zika virus disease caused most neurological alterations, and dengue resulted in greater morbidity leading to more frequent hospitalization. The review provides a broad view of the three arboviruses and the intrinsic aspects of infections, and highlights the factors that influence the spread of these viruses in the populations studied.

Chikungunya spread throughout the Dominican Republic (DR) after the first identified laboratory-confirmed cases were reported in April 2014. In June 2014, a U.S.-based service organization operating in the DR reported chikungunya-like illnesses among several staff. We assessed the incidence of chikungunya virus (CHIKV) and dengue virus (DENV) infection and illnesses and evaluated adherence to mosquito avoidance measures among volunteers/staff deployed in the DR who returned to the United States during July-August 2014. Investigation participants completed a questionnaire that collected information on demographics, medical history, self-reported illnesses, and mosquito exposures and avoidance behaviors and provided serum for CHIKV and DENV diagnostic testing by reverse transcription polymerase chain reaction and IgM enzyme-linked immunosorbent assay. Of 102 participants, 42 (41%) had evidence of recent CHIKV infection and two (2%) had evidence of recent DENV infection. Of the 41 participants with evidence of recent CHIKV infection only, 39 (95%) reported fever, 37 (90%) reported rash, and 37 (90%) reported joint pain during their assignment. All attended the organization's health trainings, and 89 (87%) sought a pretravel health consultation. Most (∼95%) used insect repellent; however, only 30% applied it multiple times daily and < 5% stayed in housing with window/door screens. In sum, CHIKV infections were common among these volunteers during the 2014 chikungunya epidemic in the DR. Despite high levels of preparation, reported adherence to mosquito avoidance measures were inconsistent. Clinicians should discuss chikungunya with travelers visiting areas with ongoing CHIKV outbreaks and should consider chikungunya when diagnosing febrile illnesses in travelers returning from affected areas.

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.