anti-CHIKV IgM Antibodies Research Articles

Serological and Molecular Epidemiology of Chikungunya Virus Infection in Vietnam, 2017-2019.

Chikungunya fever is an acute febrile illness caused by the chikungunya virus (CHIKV), which is transmitted by Aedes mosquitoes. Since 1965, only a few studies with limited scope have been conducted on CHIKV in Vietnam. Thus, this study aimed to determine the seroprevalence and molecular epidemiology of CHIKV infection among febrile patients in Vietnam from 2017 to 2019. A total of 1063 serum samples from 31 provinces were collected and tested for anti-CHIKV IgM and IgG ELISA. The 50% focus reduction neutralization test (FRNT50) was used to confirm CHIKV-neutralizing antibodies. Quantitative real-time RT-PCR (RT-qPCR) was performed to confirm the presence of the CHIKV genome. The results showed that 15.9% (169/1063) of the patients had anti-CHIKV IgM antibodies, 20.1% (214/1063) had anti-CHIKV IgG antibodies, 10.4% (111/1063) had CHIKV-neutralizing antibodies, and 27.7% (130/469) of the samples were positive in RT-qPCR analysis. The E1 CHIKV genome sequences were detected among the positive RT-qPCR samples. Our identified sequences belonged to the East/Central/South/African (ECSA) genotype, which has been prevalent in Vietnam previously, suggesting CHIKV has been maintained and is endemic in Vietnam. This study demonstrates a high prevalence of CHIKV infection in Vietnam and calls for an annual surveillance program to understand its impact.

Serological and molecular evidence of chikungunya virus infection among febrile outpatients seeking healthcare in Northern Malawi

ABSTRACT Introduction: Despite global evidence of chikungunya fever (CHIKF) in humans that is caused by chikungunya virus (CHIKV), little is known about the occurrence of CHIKF in Malawi. This study was conducted to determine the seroprevalence of CHIKF and to molecularly confirm the presence of CHIKV ribonucleic acid (RNA) among febrile outpatients seeking health care at Mzuzu Central Hospital in the Northern Region of Malawi. Methods: Enzyme-immunosorbent assay (ELISA) was used to detect the presence or absence of specific antibodies against CHIKV. Reverse transcription-polymerase chain reaction (RT-PCR) was conducted on randomly selected anti-CHIKV IgM-positive samples to detect CHIKV RNA. Results: Out of 119 CHIKF suspected samples analyzed, 73 tested positive for anti-CHIKV IgM antibodies, with an overall seroprevalence of 61.3%. Most of the CHIKV infected individuals presented with joint pain, abdominal pain, vomiting and nose bleeding with seroprevalence of 45.2%, 41.1%, 16.4% and 12.3%, respectively. All the randomly selected samples that were positive for CHIKV anti-IgM by ELISA had detectable CHIKV RNA by RT-PCR. Conclusion: The presence of anti-CHIKV IgM antibodies suggests the presence of recent CHIKV infection. We therefore recommend for the inclusion of CHIKF as the differential diagnosis in febrile ill patients in Mzuzu city, Malawi.

Seroprevalence of Chikungunya in an Asymptomatic Adult Population in North and South Sulawesi, Indonesia.

Chikungunya (CHIK) is an emerging and reemerging infectious disease of public health importance in Indonesia. Information on the asymptomatic and true burden of CHIK virus (CHIKV) infections is limited. We assayed 1,092 healthy population samples, collected in North and South Sulawesi between 2019 and 2020, for antibodies against CHIKV. Blood samples were screened by IgM and IgG ELISAs and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) assay. CHIKV IgG seroprevalence in North and South Sulawesi was 53.2% and 53.9%, respectively. The overall prevalence of anti-CHIKV IgM antibody was 12.9%. Molecular testing of blood donors revealed 0.66% (2/300) were positive for CHIKV qRT-PCR. Our study provides new insights into the CHIKV endemicity situation in the eastern part of Indonesia and warrants the need for further systematic surveillance considering there is no treatment or vaccine for CHIK infection.

Seroepidemiology of Chikungunya Fever in Dhaka, Bangladesh: A Crosssectional Study

Chikungunya fever (CHIKF) is a mosquito-borne febrile illness caused by the Chikungunya virus (CHIKV). Bangladesh has documented several outbreaks of CHIKF since it was first reported in 2008. The latest CHIKF outbreak occurred in the Dhaka in 2017. In this study, a serosurvey of the 2017 outbreak was conducted during its peak. The study involved the assessment of CHIKV immunoreactions among participants suffering from CHIKF related symptoms. One hundred blood samples were collected from patients suffering from CHIKF-associated symptoms and were subsequently tested for the presence of anti-CHIKV IgM and/or IgG antibodies. Data based on clinical symptoms and the demographics of the participants were recorded and analyzed. Seventy-four percent of the studied patients (n = 100) possessed anti-CHIKV antibodies. Among this seropositive group (n = 74), almost 62% contained anti-CHIKV IgM and IgG antibodies, whereas 10% contained only anti-CHIKV IgM antibodies indicating recent infection. Anti-CHIKV IgG antibodies were found in 28% of patients. Among the symptoms examined, polyarthralgia showed a highly significant relationship (P < 0.001), whereas high fever and the presence of rash demonstrated a significant association with CHIKV seropositivity (P < 0.05). Discoveries made on this research can better help public health officials to gain a comprehensive insight into the seroepidemiology of the condition based in the city and maintain constant vigilance against any future outbreak.
 Bangladesh J Microbiol, Volume 38, Number 2, December 2021, pp 79-85

Epidemiological surveillance of Chikungunya cases – Findings from a tertiary care hospital in New Delhi

Background: Chikungunya epidemic is a major public health problem in metro cities in India especially during rainy season. There was an epidemic of chikungunyain the year 2016 in New Delhi. Therefore, this present study was planned to understand epidemiological and clinical profile of Chikungunya cases attending fever clinic in a tertiary care teaching hospital in Delhi. Methods & Materials: A total of 200 patients with fever of up to 7 days duration who reported at fever clinic of a tertiary care hospital in New Delhi were studied over a period of 6 months. A total of 47,874 fever cases were reported in fever clinic in same duration. Serum specimens were screened for chikungunya infection by serology (IgM). Chikungunya infection was detected in 16.5% patients by anti-CHIKV IgM antibodies by ELISA. A preformed semi-structured, interviewer administered questionnaire was used for the purpose of data collection. Results: Among these 200 suspected cases of chikungunya, fever (96.0%), joint pain (81.0%), myalgia (77.5%) and lower backache (57.5%) were the major clinical features. Major joints involved were knee joint (45.5%), wrist (32.5%), hand (phalanges) (34.5%) and ankle joints (31.0%). Myalgia, rashes, joint pain and joint swelling was frequently observed among chikungunya confirmed cases (p < 0.05). All group of ages, both gender and all class of socioeconomic scale were equally susceptible to chikungunya infection. Conclusion: Chikungunya virus had a wide spectrum of clinical features and all age groups, gender and socioeconomic status people were equally susceptible to Chikungunya infection. All acute febrile illness patients with joint pain should be screened in the laboratory for both Chikungunya IgM antibodies. Predictability of chikungunya is more in presence of joint pain and swelling, myalgia and rashes. This study emphasizes the need for a continuous surveillance on the disease burden.

Molecular and phylogenetic analysis of Chikungunya virus in Central India during 2016 and 2017 outbreaks reveal high similarity with recent New Delhi and Bangladesh strains

Central India witnessed Chikungunya virus (CHIKV) outbreaks in 2016 and 2017. The present report is a hospital based cross-sectional study on the serological and molecular epidemiology of the outbreak. Mutational and phylogenetic analysis was conducted to ascertain the genetic relatedness of the central Indian strains with other Indian and global strains. Chikungunya infection was confirmed in the clinically suspected patients by the detection of anti-CHIKV IgM antibody by ELISA and viral RNA by RT-PCR. A representative set of the RT-PCR positive samples were sequenced for E1 gene and analyzed to identify the emerging mutations and establish their phylogenetic relationship, particularly with other contemporary strains. Phylogenetic analysis revealed the present strains to be of East Central South African (ECSA) genotype. Emergence of a variant strain was observed in the year 2016, which became the predominant strain in this region in 2017. The strains showed significant identity with recent New Delhi strains of 2015 and 2016 and Bangladesh strains of 2017. The epidemic mutation A226V which emerged in 2006 outbreaks of India and Indian Ocean Islands was found to be absent in the current strains. Among the important mutations viz. K211E, M269 V, D284E, I317V & V322A observed in the recent strains. I317V is a novel mutation which has emerged very recently as it was found only in central Indian (2016, 2017), New Delhi strains (2015, 2016) and Bangladesh strains (2017). This study has identified a unique mutation E1:I317V in the Central Indian strains, which is present only in recent New Delhi and Bangladesh strains till date. This study highlights the need for continuous molecular surveillance of circulating CHIKV strains in order to facilitate the prompt identification of novel strains of this virus and enable the elucidation of their clinical correlates.

Chikungunya virus infection in Indonesia: a systematic review and evolutionary analysis

BackgroundDespite the high number of chikungunya cases in Indonesia in recent years, comprehensive epidemiological data are lacking. The systematic review was undertaken to provide data on incidence, the seroprevalence of anti-Chikungunya virus (CHIKV) IgM and IgG antibodies, mortality, the genotypes of circulating CHIKV and travel-related cases of chikungunya in the country. In addition, a phylogenetic and evolutionary analysis of Indonesian CHIKV was conducted.MethodsA systematic review was conducted to identify eligible studies from EMBASE, MEDLINE, PubMed and Web of Science as of October 16th 2017. Studies describing the incidence, seroprevalence of IgM and IgG, mortality, genotypes and travel-associated chikungunya were systematically reviewed. The maximum likelihood phylogenetic and evolutionary rate was estimated using Randomized Axelerated Maximum Likelihood (RAxML), and the Bayesian Markov chain Monte Carlo (MCMC) method identified the Time to Most Recent Common Ancestors (TMRCA) of Indonesian CHIKV. The systematic review was registered in the PROSPERO database (CRD42017078205).ResultsChikungunya incidence ranged between 0.16-36.2 cases per 100,000 person-year. Overall, the median seroprevalence of anti-CHIKV IgM antibodies in both outbreak and non-outbreak scenarios was 13.3% (17.7 and 7.3% for outbreak and non-outbreak events, respectively). The median seroprevalence of IgG antibodies in both outbreak and non-outbreak settings was 18.5% (range 0.0–73.1%). There were 130 Indonesian CHIKV sequences available, of which 120 (92.3%) were of the Asian genotype and 10 (7.7%) belonged to the East/Central/South African (ECSA) genotype. The ECSA genotype was first isolated in Indonesia in 2008 and was continually sampled until 2011. All ECSA viruses sampled in Indonesia appear to be closely related to viruses that caused massive outbreaks in Southeast Asia countries during the same period. Massive nationwide chikungunya outbreaks in Indonesia were reported during 2009–2010 with a total of 137,655 cases. Our spatio-temporal, phylogenetic and evolutionary data suggest that these outbreaks were likely associated with the introduction of the ECSA genotype of CHIKV to Indonesia.ConclusionsAlthough no deaths have been recorded, the seroprevalence of anti-CHIKV IgM and IgG in the Indonesian population have been relatively high in recent years following re-emergence in early 2001. There is sufficient evidence to suggest that the introduction of ECSA into Indonesia was likely associated with massive chikungunya outbreaks during 2009–2010.

An epidemic of chikungunya in northwestern Bangladesh in 2011.

BackgroundIn November 2011, a government hospital physician in Shibganj sub-district of Bangladesh reported a cluster of patients with fever and joint pain or rash. A multi-disciplinary team investigated to characterize the outbreak; confirm the cause; and recommend control and prevention measures.MethodsShibganj's residents with new onset of fever and joint pain or rash between 1 September and 15 December 2011 were defined as chikungunya fever (CHIKF) suspect cases. To estimate the attack rate, we identified 16 outpatient clinics in 16 selected wards across 16 unions in Shibganj and searched for suspect cases in the 80 households nearest to each outpatient clinic. One suspect case from the first 30 households in each ward was invited to visit the nearest outpatient clinic for clinical assessment and to provide a blood sample for laboratory testing and analyses.ResultsWe identified 1,769 CHIKF suspect cases from among 5,902 residents surveyed (30%). Their median age was 28 (IQR:15−42) years. The average attack rate in the sub-district was 30% (95% CI: 27%−33%). The lowest attack rate was found in children <5 years (15%). Anti-CHIKV IgM antibodies were detected by ELISA in 78% (264) of the 338 case samples tested. In addition to fever, predominant symptoms of serologically-confirmed cases included joint pain (97%), weakness (54%), myalgia (47%), rash (42%), itching (37%) and malaise (31%). Among the sero-positive patients, 79% (209/264) sought healthcare from outpatient clinics. CHIKV was isolated from two cases and phylogenetic analyses of full genome sequences placed these viruses within the Indian Ocean Lineage (IOL). Molecular analysis identified mutations in E2 and E1 glycoproteins and contained the E1 A226V point mutation.ConclusionThe consistently high attack rate by age groups suggested recent introduction of chikungunya in this community. Mosquito control efforts should be enhanced to reduce the risk of continued transmission and to improve global health security.

Experience of Perinatal and Neonatal Chikungunya Virus (CHIKV) Infection in a Tertiary Care Neonatal Centre during Outbreak in North India in 2016: A Case Series

In 2016, there was a massive outbreak of chikungunya in North India. During the epidemic, we observed many neonatal and early infantile cases of chikungunya, with a probable perinatal transmission. This retrospective study was carried out in a tertiary care neonatal centre between August 2016 and November 2016. Chikungunya virus (CHIKV) infection was detected and confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and/or serology (anti-CHIKV IgM) in mothers and infants. Clinical features and laboratory parameters were recorded. There were 16 cases of confirmed CHIKV infections during the study period. For babies presenting during the neonatal period (n = 13), the median age of presentation was 9.5 (range: 3-15) days, whereas for babies (three) presenting after the neonatal period, the median age was between 1 and 3 months. The most common presentation was fever (69%), followed by lethargy (56%) and seizures (50%). Skin manifestations were observed in 25% of the cases, which included maculopapular rashes, bullous lesions and hyperpigmentation over the axilla, perioral and genital areas. None of the cases had any feature of arthritis. Of all the cases included in the study (n = 16), RT-PCR for CHIKV was positive in 14 (87.5%), whereas the serum anti-CHIKV IgM antibody test was positive in two (12.5%) cases. Six (37.5%) cases were documented as perinatal CHIKV, as RT-PCR for CHIKV was positive in both mothers and babies. Fifteen babies survived and were discharged in a stable condition with no oxygen requirement and on full feeds. One baby died because of multi-organ failure and catecholamine refractory hypotension. In endemic areas, paediatricians should have a low threshold of suspicion for perinatal or neonatal chikungunya in any infant presenting with signs and symptoms mimicking sepsis, especially with skin manifestations, seizure and/or encephalopathy.

Chikungunya Infection: a Global Public Health Menace.

Chikungunya virus (CHIKV) has been involved in epidemics in African and Asian subcontinents and, of late, has transcended to affect the Americas. Aedes aegypti and Aedes albopictus are the major vectors for CHIKV infection, which results in dissemination of virus to various vital organs. Entry of virus into these tissues causes infiltration of innate immune cells, monocytes, macrophages, neutrophils, natural killer cells, and adaptive immune cells. Macrophages bearing the replicating virus, in turn, secrete pro-inflammatory cytokines IL-1β, TNF-α, and IL-17. Together, this pro-inflammatory milieu induces osteoclastogenesis, bone loss, and erosion. CHIKV is characterized by fever, headache, myalgia, rash, and symmetric polyarthritis, which is generally self-limiting. In a subset of cases, however, musculoskeletal symptoms may persist for up to 3-5years. Viral culture and isolation from blood cells of infected patients are the gold standards for diagnosis of CHIKV. In routine practice, however, assays for anti-CHIKV IgM antibodies are used for diagnosis, as elevated levels in blood of infected patients are noted from 10days following infection for up to 3-6months. Early diagnosis of CHIKV is possible by nucleic acid detection techniques. Treatment of acute CHIKV is mainly symptomatic, with analgesics, non-steroidal anti-inflammatory agents (NSAIDs), and low-dose steroids. No vaccines or anti-viral medicines have been approved for clinical therapy in CHIKV as yet. Hydroxychloroquine and methotrexate have been used in chronic CHIKV infection with variable success.

Comparative sensitivity of RICA and MAC-ELISA for IGM antibody based early diagnosis of chikungunya virus infection in patients in Kadapa district of Andhra Pradesh, India

Chikungunya (CHIK) is a viral fever that spreads in human population through mosquito bite that is infected with Chikungunya virus (CHIKV). CHIK resembles Dengue fever. Although there is no specific treatment or vaccine available currently, the confirmative rapid diagnosis is based on detection of viral nucleic acid or IgM antibodies in serum, an indication of recent infection, helps in epidemiological monitoring, symptomatic treatment of patients and determining prognosis. In the present study, with the approval of the Kadapa district medical and health officer, 238 blood samples were collected from Chikungunya infection suspected patients, residing in the Kadapa district villages of Andhra Pradesh. Serological detection of anti-CHIKV IgM antibodies was performed using rapid immuno-chromatographic assay (RICA) and IgM-antibody capture enzyme-linked immuno Sorbant assay (MAC-ELISA). Convalescent sera (n = 170) were tested by RICA and 108 of them were found positive for anti-CHIKV IgM antibodies. All 108 anti-CHIKV IgM antibody RICA positive sera were further assayed using MAC-ELISA to compare the sensitivity of both assays for the early diagnosis of disease. Only 45 sera samples gave positive result. The sensitivity of RICA and MAC-ELISA were found to be 100% and 42% respectively.

Evidence for Endemic Chikungunya Virus Infections in Bandung, Indonesia

Chikungunya virus (CHIKV) is known to cause sporadic or explosive outbreaks. However, little is known about the endemic transmission of CHIKV. To ascertain the endemic occurrence of CHIKV transmission, we tested blood samples from patients with a non-dengue febrile illness who participated in a prospective cohort study of factory workers in Bandung, Indonesia. From August 2000 to June 2004, and September 2006 to April 2008, 1901 febrile episodes occurred and 231 (12.2%) dengue cases were identified. The remaining febrile cases were evaluated for possible CHIKV infection by measuring anti-CHIKV IgM and IgG antibodies in acute and convalescent samples. Acute samples of serologically positive cases were subsequently tested for the presence of CHIKV RNA by RT-PCR and/or virus isolation. A total of 135 (7.1%) CHIKV infections were identified, providing an incidence rate of 10.1/1,000 person years. CHIKV infections were identified all year round and tended to increase during the rainy season (January to March). Severe illness was not found and severe arthralgia was not a prominently reported symptom. Serial post-illness samples from nine cases were tested to obtain a kinetic picture of IgM and IgG anti-CHIKV antibodies. Anti-CHIKV IgM antibodies were persistently detected in high titers for approximately one year. Three patients demonstrated evidence of possible sequential CHIKV infections. The high incidence rate and continuous chikungunya cases in this adult cohort suggests that CHIKV is endemically transmitted in Bandung. Further characterization of the circulating strains and surveillance in larger areas are needed to better understand CHIKV epidemiology in Indonesia.

Travelers as Sentinels for Chikungunya Fever, Brazil

Travelers as Sentinels for Chikungunya Fever, Brazil

Chikungunya outbreak in a rural area of Western Cameroon in 2006: A retrospective serological and entomological survey

BackgroundAlthough arboviral infections including Chikungunya virus (CHIKV) are common in sub-Saharan Africa, data on their circulation and prevalence are poorly documented. In 2006, more than 400 cases of dengue-like fever were reported in Kumbo (Northwest Region of Cameroon). The aim of this study was to identify the aetiology of this fever and to define its extent in the area.MethodsWe conducted a cross-sectional seroprevalence survey one year after clinical investigations to define the extent of the infection. An entomological survey consisted of the collection and identification of mosquito immature stages in water containers in or around human dwellings.ResultsA total of 105 sera were obtained from volunteers and tested for CHIKV, O'Nyong-nyong virus (ONNV) and Dengue virus (DENV) specific IgM and IgG antibodies by enzyme-linked immunosorbent assays (ELISA). CHIKV infection was defined as the presence of IgM antibodies to CHIKV. There was serological evidence for recent Chikungunya infection, as 54 subjects (51.4%) had detectable IgM anti-CHIKV in their sera. Amongst these, 52 showed both anti-CHIKV IgM and IgG, and 2 (1.9%) had IgM anti-CHIKV in the absence of IgG. Isolated anti-CHIKV IgG positives were detected in 41 (39%) cases. No anti-ONNV and anti-DENV IgM antibodies were found amongst the sample tested. Out of 305 larvae collected in the different breeding sites, 87 developed to the adult stage; 56 (64.4%) were Aedes africanus and the remaining Culex spp.ConclusionsThese findings suggest that the outbreak of febrile illness reported in three villages of Western Cameroon was due to CHIKV. The issue of a possible persistence of anti-CHIKV IgM antibodies is discussed. Ae. africanus which was found to be relatively abundant among the raffia palm bushes probably plays a role in the transmission of CHIKV along the chain of sylvatic/domestic mosquito species in this rural area. Particular attention should therefore be given to arbovirus infections in the Central African sub-region where these infections are becoming an emerging public health threat.

An outbreak of chikungunya in southern Thailand from 2008 to 2009 caused by African strains with A226V mutation

To elucidate clinical and molecular characteristics of chikungunya fever (CHIK fever) from the 2008-2009 outbreak caused by chikungunya virus (CHIKV) in southern Thailand. Three hundred and eighty-one sera from 332 patients with acute febrile illness were tested for anti-CHIKV IgM antibody by ELISA. A molecular analysis of these sera was performed using a semi-nested reverse transcriptase polymerase chain reaction (RT-PCR), followed by direct sequencing and phylogenetic analysis. One hundred and seventy-nine patients were diagnosed with CHIK fever by molecular analysis and/or anti-CHIKV IgM antibody detection. Patients diagnosed with CHIK fever were significantly older than controls (mean age 38.8±19 vs. 28.7±18 years, p<0.0001) and presented with arthralgia more often than controls. One hundred percent of the sera were positive by RT-PCR, whereas only 10% were positive in serological tests for anti-CHIKV IgM antibody by ELISA if the serum was obtained during the first 4 days of fever. In contrast, CHIKV-specific IgM antibody by ELISA was found in 100% of patients, whereas 15% of patients were positive by RT-PCR if the serum was obtained more than 9 days after the onset of fever. RT-PCR for CHIKV should be performed if the patients present within the first 4 days of fever. Patients presenting after at least 9 days of fever should be tested for IgM antibody. Based on phylogenetic analysis, the CHIKV strains isolated belong to African genotypes harboring the E1 A226V mutation, indicating a single origin of the 2004-2009 CHIKV outbreaks. The novel CHIKV mutation could potentially modify the epidemiological presentation of CHIK fever. Early diagnosis of CHIK fever is essential for preventing further massive outbreaks.