Chikungunya and dengue virus infections during pregnancy: seroprevalence, seroincidence and maternal-fetal transmission, southern Thailand, 2009-2010.

Risk for Emergence of Dengue and Chikungunya Virus in Israel

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.

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.

Chikungunya virus: An emerging public health challenge for Pakistan

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.

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.

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.

Seroprevalence of chikungunya virus infection in India, 2017: a cross-sectional population-based serosurvey

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

To the Editor: Chikungunya virus (CHIKV), an arthropod-borne virus transmitted to humans by Aedes spp. mosquitoes, was first isolated in Tanzania (Tanganyika) in 1953 (1). Various outbreaks have since occurred in Africa, Southeast Asia, and India (2). CHIKV has recently been reported in a large area in the Indian Ocean islands and the Indian subcontinent. After an outbreak in Kenya in 2004, other outbreaks occurred in early 2005 on the Comoros Islands, Reunion, and other islands in the southwestern Indian Ocean; the epidemic then spread to India (3,4). Molecular analysis showed that the epidemic was caused by a variant of the Central/East African CHIKV genotype (5,6). Internet surveillance networks provided information on epidemics in real time, alerting clinicians in the industrialized world to the spread of CHIKV and enabling them to more easily diagnose infection among travelers with fevers (7). We report results of diagnostic tests and analysis of predictors of infection among persons in Italy with symptoms suggestive of CHIKV infection who had traveled to potentially affected areas. Dengue virus (DENV) is endemic to many of these areas. We studied travelers or migrants from areas to which CHIKV infection is endemic (i.e., sub-Saharan Africa) or areas currently affected by outbreaks (i.e., the Indian Ocean islands, India) who had symptoms suggestive of infection (i.e., fever and arthralgia with or without a rash) from January 2006 through March 2007. At least 1 blood sample was collected from each patient and stored at –80°C before testing for CHIKV and DENV. Median lag between onset of symptoms and date of blood collection was 22 days (range 3–179 days). Two samples (acute phase and convalescence phase) were available from 5 patients. Serologic diagnosis of CHIKV infection was determined by hemagglutination inhibition (HI) test and confirmed by plaque-reduction neutralization test (8). Serodiagnosis of DENV infection was conducted by using the HI test and an immunoglobulin M ELISA (Focus Diagnostics, Cypress, CA, USA). A case-report form containing information about age, sex, countries visited, travel dates, and date of onset of symptoms was completed for each patient. Seventy-six persons participated in the study; 55.3% were male, median age was 39 years (range 1–69 years), and most (80.3%) were Italian (Table). A total of 29 (38.2%) were positive for CHIKV, and 13 (17.1%) were positive for DENV; 34 (44.7%) were negative for both viruses. Of the 29 CHIKV-positive persons, 22 (75.9%) had visited the Indian Ocean islands (Mauritius, Reunion, and Madagascar), 5 had visited Asia, and 2 had visited Africa. Travelers from Indian Ocean islands had a higher risk for CHIKV infection than those who had visited Africa (odds ratio [OR] 11.0, 95% confidence interval [CI] 1.60–119.13) or Asia (OR 17.05, 95% CI 4.31–73.05). Persons who had visited Asia had a higher risk for DENV infection (OR 8.36; 95% CI 1.58–81.73) than those who had visited other areas. Table Characteristics of 76 travelers studied The 5 persons who were infected with CHIKV in Asia had visited India (i.e., the most visited country [21 travelers]). However, persons who visited the Indian Ocean islands had a higher risk of being CHIKV positive than those who had visited India (OR 8.8, 95% CI 2.09–39.86). A rash was associated with CHIKV infection and was >8× more likely to be reported by CHIKV-positive persons than CHIKV-negative persons (OR 7.03, 95% CI 2.23–22.93). Moreover, rash was observed in 65% of CHIKV-positive cases and 31% of DENV-positive cases, but the difference was not statistically significant because of the small sample size (OR 4.28, 95% CI 0.88–23.23). None of the other patient’s characteristics was associated with infection with CHIKV or DENV. A limitation of our study was that only 5 patients had documented seroconversion for CHIKV. However, high titers were found in all but 1 patient (>1,280 in 21 patients and 640 in 2 patients). This patient, who had a titer of 80, was an Italian who had probably not been previously exposed to CHIKV. Thus, the risk for misclassification was low. PCR for early detection of infection was not used because only 3 persons were tested within 10 days of symptom onset. Two of these persons, who were tested 7 days after symptom onset, already had antibodies to CHIKV. In conclusion, a high proportion of travelers with symptoms of CHIKV infection who returned from areas with outbreaks of this infection or where this virus was endemic were seropositive. A lower proportion of patients had antibodies to DENV. CHIKV-positive patients were more likely to have a rash than those negative for both CHIKV and DENV. As suggested by previous studies (9), a rash was more common among CHIKV-positive patients than in DENV-infected patients, but the difference was not significant. Our study suggests that identification of predictors of infection with CHIKV is feasible, although it is complicated by cocirculation of DENV in the same areas.

Objective:Chikungunya is a disease caused by Aedes mosquito-borne chikungunya virus infection. This disease is becoming one of the emerging/re-emerging viral diseases in tropical and subtropical countries but is neglected by public health systems. This study assessed the seroprevalence of chikungunya virus infection among patients with acute febrile illness seeking healthcare in a malaria-endemic area in the Afar Region, Northeast Ethiopia.Methods:An institution-based cross-sectional study was employed from September 2022 to March 2023 to assess the seroprevalence of chikungunya virus infection among malaria-suspected febrile patients attending health institutes in the Afar Region. Sociodemographic, clinical features, and venous blood were collected from each study participant. Blood films were prepared and examined for plasmodium infection using microscopy. Sera were separated and screened for anti-chikungunya virus IgM and IgG antibodies using an enzyme-linked immunosorbent assay. Data were entered into Epi Data 3.1 and analyzed using Stata/SE 14.2.Results:In this study, 368 malaria-suspected febrile patients (55.4% female, aged 5–80 years old, mean ± SD = 27.28 ± 14.0) participated. The prevalence of anti-chikungunya virus IgM antibodies, indicating acute infection, was 47.8%, while the prevalence of IgG antibodies, indicating previous exposure, was 6.3%. Nonmarried participants were found to be more likely to have acute chikungunya virus infection (AOR = 2.34, 95% CI: 1.141–4.964), and back pain was associated with higher likelihood of acute infection (AOR = 1.785; 95% CI: 1.078–2.954). About 10.6% of the participants tested positive for Plasmodium parasite infection, with P. falciparum (84.6%) being the most common, followed by P. vivax (10.3%) and mixed (5.1%) infections.Conclusion:The study revealed a high seroprevalence of acute chikungunya virus infection among febrile patients in the Afar Region, highlighting the importance of regular screening for arbovirus infection in febrile patients to control and mitigate chikungunya spread.

BackgroundSince 2006, Chikungunya virus (CHIKV) has re-emerged as an important pathogen of global concern. However, individual and household factors associated with the acquisition and the magnitude of clinically silent CHIKV infections remain poorly understood. In this present study, we aimed to investigate the seroprevalence, estimate the proportion of symptomatic illness and identify the risk factors for CHIKV infection in the primo-exposed population of Mayotte.Methods/ Principal FindingsWe conducted a household-based cross sectional serosurvey in Mayotte in November and December 2006 using complex multistage cluster sampling. To produce the results representative of the island population aged 2 years or older, sample data were adjusted with sample weights. Explanatory and multiple logistic regression analyses were performed to investigate associations between CHIKV infection seropositivity (presence of IgM and/or IgG to CHIKV by enzyme-linked immunoabsorbent assay) and risk factors. A total of 1154 individuals were analyzed. The overall seroprevalence of CHIKV infection was 37·2% (95% CI = 33·9–40·5), 318 (72·3%) of the seropositive participants reported symptoms consistent with a CHIKV infection during the epidemic period. Risk factors for CHIKV seropositivity among adults (aged 15 years and older) were male gender, low socioeconomic index, schooling ≤6 years and living in makeshift housing.ConclusionsOur findings indicate that roughly one out of four CHIKV infections is asymptomatic. Conditions associated with poverty may be considered as critical in CHIKV acquisition. Thus, these conditions should be taken into account in the development of future prevention strategies of CHIKV disease.

BackgroundArboviruses are a cause of acute febrile illness and outbreaks worldwide. Recent outbreaks of Chikungunya virus (CHIKV) in dengue endemic areas have alarmed clinicians as unique clinical features differentiating CHIKV from Dengue virus (DENV) are limited. This has complicated diagnostic efforts especially in resource limited countries where lab testing is not easily available. Therefore, it is essential to analyse and compare clinical features of laboratory confirmed cases to assist clinicians in suspecting possible CHIKV infection at time of clinical presentation.MethodologyA prospective point prevalence study was conducted, with the hypothesis that not all patients presenting with clinical suspicion of dengue infections at local hospitals are suffering from dengue and that other arboviruses such as Chikungunya, West Nile viruses, Japanese Encephalitis virus and Zika virus are co-circulating in the Sindh region of Pakistan. Out-patients and hospitalized (in-patients) of selected district hospitals in different parts of Sindh province of Pakistan were recruited. Patients with presumptive dengue like illness (Syndromic diagnosis) by the treating physicians were enrolled between 2015 and 2017.Current study is a subset of larger study mentioned above. Here-in we compared laboratory confirmed cases of CHIKV and DENV to assess clinical features and laboratory findings that may help differentiate CHIKV from DENV infection at the time of clinical presentation.ResultsNinety-eight (n = 98) cases tested positive for CHIKV, by IgM and PCR and these were selected for comparative analysis with DENV confirmed cases (n = 171). On multivariable analysis, presence of musculoskeletal [OR = 2.5 (95% CI:1.6–4.0)] and neurological symptoms [OR = 4.4 (95% CI:1.9–10.2)], and thrombocytosis [OR = 2.2 (95% CI:1.1–4.0)] were associated with CHIKV infection, while atypical lymphocytes [OR = 8.3 (95% CI:4.2–16.7)] and thrombocytopenia [OR = 8.1 (95% CI:1.7–38.8)] were associated with DENV cases at time of presentation. These findings may help clinicians in differentiating CHIKV from DENV infection.ConclusionCHIKV is an important cause of illness amongst patients presenting with acute febrile illness in Sindh region of Pakistan. Arthralgia and encephalitis at time of presentation among patients with dengue-like illness should prompt suspicion of CHIKV infection, and laboratory confirmation must be sought.

Seroprevalence of chikungunya virus infection in five hospitals within Anyigba, Kogi State of Nigeria

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.