Persistent Arthralgia Associated with Chikungunya Virus Outbreak, US Virgin Islands, December 2014-February 2016

Co-circulation of two Alphaviruses in Burkina Faso: Chikungunya and O'nyong nyong viruses

BACKGROUND

Chikungunya virus (CHIKV) and O'nyong nyong virus (ONNV) are phylogenetically related alphaviruses in the Semliki Forest Virus (SFV) antigenic complex of the Togaviridae family. There are limited data on the circulation of these two viruses in Burkina Faso. The aim of our study was to assess their circulation in the country by determining seroprevalence to each of the viruses in blood donor samples and by retrospective molecular and serological testing of samples collected as part of national measles and rubella surveillance.

METHODOLOGY/PRINCIPAL FINDINGS

All blood donor samples were analyzed on the Luminex platform using CHIKV and ONNV E2 antigens. Patient samples collected during national measles-rubella surveillance were screened by an initial ELISA for CHIKV IgM (CHIKjj Detect IgM ELISA) at the national laboratory. The positive samples were then analyzed by a second ELISA test for CHIKV IgM (CDC MAC-ELISA) at the reference laboratory. Finally, samples that had IgM positive results for both ELISA tests and had sufficient residual volume were tested by plaque reduction neutralization testing (PRNT) for CHIKV and ONNV. These same patient samples were also analyzed by rRT-PCR for CHIKV. Among the blood donor specimens, 55.49% of the samples were positive for alphaviruses including both CHIKV and ONNV positive samples. Among patient samples collected as part of national measles and rubella surveillance, 3.09% were IgM positive for CHIKV, including 2.5% confirmed by PRNT. PRNT failed to demonstrate any ONNV infections in these samples. No samples tested by RT-qPCR. had detectable CHIKV RNA.

CONCLUSIONS/SIGNIFICANCE

Our results suggest that CHIKV and ONNV have been circulating in the population of Burkina Faso and may have been confused with malaria, dengue fever or other febrile diseases such as measles or rubella. Our study underscores the necessity to enhance arbovirus surveillance systems in Burkina Faso.

Current Status of Omics Studies Elucidating the Features of Reproductive Biology in Blood-Feeding Insects

Female insects belonging to the genera Anopheles, Aedes, Glossina, and Rhodnius account for the majority of global vector-borne disease mortality. In response to mating, these female insects undergo several molecular, physiological, and behavioral changes. Studying the dynamic post-mating molecular responses in these insects that transmit human diseases can lead to the identification of potential targets for the development of novel vector control methods. With the continued advancements in bioinformatics tools, we now have the capability to delve into various physiological processes in these insects. Here, we discuss the availability of multiple datasets describing the reproductive physiology of the common blood-feeding insects at the molecular level. Additionally, we compare the male-derived triggers transferred during mating to females, examining both shared and species-specific factors. These triggers initiate post-mating genetic responses in female vectors, affecting not only their reproductive success but also disease transmission.

Chikungunya: risks for travellers

RATIONALE FOR REVIEW

Chikungunya outbreaks continue to occur, with changing epidemiology. Awareness about chikungunya is low both among the at-risk travellers and healthcare professionals, which can result in underdiagnosis and underreporting. This review aims to improve awareness among healthcare professionals regarding the risks of chikungunya for travellers.

KEY FINDINGS

Chikungunya virus transmission to humans occurs mainly via daytime-active mosquitoes, Aedes aegypti and Aedes albopictus. The areas where these mosquitoes live is continuously expanding, partly due to climate changes. Chikungunya is characterized by an acute onset of fever with joint pain. These symptoms generally resolve within 1-3 weeks but at least one-third of the patients suffer from debilitating rheumatologic symptoms for months to years. Large outbreaks in changing regions of the world since the turn of the 21st century (e.g. Caribbean, La Réunion; currently Brazil, India) have resulted in growing numbers of travellers importing chikungunya, mainly to Europe and North America. Viremic travellers with chikungunya infection have seeded chikungunya clusters (France, United States of America) and outbreaks (Italy in 2007 and 2017) in non-endemic countries where Ae. albopictus mosquitoes are present. Community preventive measures are important to prevent disease transmission by mosquitoes. Individual preventive options are limited to personal protection measures against mosquito bites, particularly the daytime-active mosquitos that transmit the chikungunya virus. Candidate vaccines are on the horizon and regulatory authorities will need to assess environmental and host risk factors for persistent sequelae, such as obesity, age (over 40 years), and history of arthritis or inflammatory rheumatologic disease to determine which populations should be targeted for these chikungunya vaccines.

CONCLUSIONS/RECOMMENDATIONS

Travellers planning to visit destinations with active CHIKV circulation should be advised about the risk for chikungunya, prevention strategies, the disease manifestations, possible chronic rheumatologic sequelae, and if symptomatic, seek medical evaluation and report potential exposures.

The global burden of Chikungunya fever among children: A systematic literature review and meta-analysis

Chikungunya fever (CHIKF) is an arboviral illness that was first described in Tanzania (1952). In adults, the disease is characterised by debilitating arthralgia and arthritis that can persist for months, with severe illness including neurological complications observed in the elderly. However, the burden, distribution and clinical features of CHIKF in children are poorly described. We conducted a systematic literature review and meta-analysis to determine the epidemiology of CHIKF in children globally by describing its prevalence, geographical distribution, and clinical manifestations. We searched electronic databases for studies describing the epidemiology of CHIKF in children. We included peer-reviewed primary studies that reported laboratory confirmed CHIKF. We extracted information on study details, sampling approach, study participants, CHIKF positivity, clinical presentation and outcomes of CHIKF in children. The quality of included studies was assessed using Joanna Briggs Institute Critical Appraisal tool for case reports and National Institute of Health quality assessment tool for quantitative studies and case series. Random-effects meta-analysis was used to estimate the pooled prevalence of CHIKF among children by geographical location. We summarised clinical manifestations, laboratory findings, administered treatment and disease outcomes associated with CHIKF in children. We identified 2104 studies, of which 142 and 53 articles that met the inclusion criteria were included in the systematic literature review and meta-analysis, respectively. Most of the selected studies were from Asia (54/142 studies) and the fewest from Europe (5/142 studies). Included studies were commonly conducted during an epidemic season (41.5%) than non-epidemic season (5.1%). Thrombocytopenia was common among infected children and CHIKF severity was more prevalent in children <1 year. Children with undifferentiated fever before CHIKF was diagnosed were treated with antibiotics and/or drugs that managed specific symptoms or provided supportive care. CHIKF is a significant under-recognised and underreported health problem among children globally and development of drugs/vaccines should target young children.

Posaconazole inhibits multiple steps of the alphavirus replication cycle

Repurposing drugs is a promising strategy to identify therapeutic interventions against novel and re-emerging viruses. Posaconazole is an antifungal drug used to treat invasive aspergillosis and candidiasis. Recently, posaconazole and its structural analog, itraconazole were shown to inhibit replication of multiple viruses by modifying intracellular cholesterol homeostasis. Here, we show that posaconazole inhibits replication of the alphaviruses Semliki Forest virus (SFV), Sindbis virus and chikungunya virus with EC₅₀ values ranging from 1.4 μM to 9.5 μM. Posaconazole treatment led to a significant reduction of virus entry in an assay using a temperature-sensitive SFV mutant, but time-of-addition and RNA transfection assays indicated that posaconazole also inhibits post-entry stages of the viral replication cycle. Virus replication in the presence of posaconazole was partially rescued by the addition of exogenous cholesterol. A transferrin uptake assay revealed that posaconazole considerably slowed down cellular endocytosis. A single point mutation in the SFV E2 glycoprotein, H255R, provided partial resistance to posaconazole as well as to methyl-β-cyclodextrin, corroborating the effect of posaconazole on cholesterol and viral entry. Our results indicate that posaconazole inhibits multiple steps of the alphavirus replication cycle and broaden the spectrum of viruses that can be targeted in vitro by posaconazole, which could be further explored as a therapeutic agent against emerging viruses.

Epidemiology and Laboratory Diagnostics of Dengue, Yellow Fever, Zika, and Chikungunya Virus Infections in Africa

Arbovirus infections are widespread, and their disease burden has increased in the past decade. In Africa, arbovirus infections and fever with unknown etiology are common. Due to the lack of well-established epidemiologic surveillance systems and accurate differential diagnosis in most African countries, little is known about the prevalence of human arbovirus infections in Africa. The aim of this review is to summarize the available epidemiological data and diagnostic laboratory tools of infections with dengue, yellow fever, Zika, and chikungunya viruses, all transmitted by Aedes mosquitoes. Studies indicate that these arboviral infections are endemic in most of Africa. Surveillance of the incidence and prevalence of the infections would enable medical doctors to improve the diagnostic accuracy in patients with typical symptoms. If possible, arboviral diagnostic tests should be added to the routine healthcare systems. Healthcare providers should be informed about the prevalent arboviral diseases to identify possible cases.

Arthralgia resolution rate following chikungunya virus infection

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This study investigated the duration of persistence of chikungunya-related arthralgia.

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Statisticalanalysis of multiple cohorts of chikungunya patients was performed.

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First estimates of the average rate of chronic chikungunya virus arthralgia resolution were calculated.

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Varying rates of arthralgia resolution are associated with age and other factors.

Background

Arthralgia, persistent pain or stiffness of the joints, is the hallmark symptom of chronic chikungunya virus (CHIKV) disease. Associated with significant disability and reduced quality of life, arthralgia can persist for many months following CHIKV infection. Understanding the expected duration of arthralgia persistence is important for managing clinical expectations at the individual-level as well as for estimating long-term burdens on population health following a CHIKV epidemic.

Methods

A review of cohort studies reporting the prevalence of arthralgia post-CHIKV infection over multiple time points was conducted. Generalized linear models were used to estimate the average rate of arthralgia resolution following CHIKV infection.

Results

Sixteen cohort studies matching the inclusion criteria were identified and included in the analysis. An average rate of arthralgia resolution of 10.85% (95% confidence interval (CI) 9.05–12.66%) per month was estimated across studies, corresponding to an expected median time to arthralgia resolution of 6.39 months (95% CI 5.48–7.66 months) and an expected arthralgia prevalence of 72.21% (95% CI 68.40–76.23%) at 3 months post-CHIKV infection.

Conclusions

Estimates of the average rate of arthralgia resolution and the expected prevalence of arthralgia over time post-CHIKV infection were derived. These can help inform expectations regarding the long-term public health burdens associated with CHIKV epidemics.

Chikungunya fever in Africa: a systematic review

Since the identification of chikungunya virus (CHIKV), sporadic cases and outbreaks were reported in several African countries, on the Indian subcontinent, and in south-east Asia. In the last 20 years, there is a growing number of reports of CHIKV infections from African countries, but the overall picture of its circulation at the continent level remains ill-characterized because of under-diagnosis and under-reporting. Moreover, the public health impact of the infection in Africa is generally poorly understood, especially during outbreak situations. Our work has the aim to review available data on CHIKV circulation in Africa to facilitate the understanding of underlying reasons of its increased detection in the African continent.

Epidemiology of Dengue, Chikungunya, and Zika Virus Disease in U.S. States and Territories, 2017

Dengue, chikungunya, and Zika viruses, primarily transmitted by Aedes species mosquitoes, have caused large outbreaks in the Americas, leading to travel-associated cases and local mosquito-borne transmission in the United States. We describe the epidemiology of dengue, chikungunya, and noncongenital Zika virus disease cases reported from U.S. states and territories in 2017, including 971 dengue cases, 195 chikungunya cases, and 1,118 Zika virus disease cases. Cases of all three diseases reported from the territories were reported as resulting from local mosquito-borne transmission. Cases reported from the states were primarily among travelers, with only seven locally acquired mosquito-transmitted Zika virus disease cases reported from Texas (n = 5) and Florida (n = 2). In the territories, most dengue cases (n = 508, 98%) were reported from American Samoa, whereas the majority of chikungunya (n = 39, 100%) and Zika virus disease (n = 620, 93%) cases were reported from Puerto Rico. Temporally, the highest number of Zika virus disease cases occurred at the beginning of the year, followed by a sharp decline, mirroring decreasing case numbers across the Americas following large outbreaks in 2015 and 2016. Dengue and chikungunya cases followed a more seasonal pattern, with higher case numbers from July through September. Travelers to the United States and residents of areas with active virus transmission should be informed of both the ongoing risk from dengue, chikungunya, and Zika virus disease and personal protective measures to lower their risk of mosquito bites and to help prevent the spread of these diseases.

Antibodies for Venezuelan Equine Encephalitis Virus Protect Embryoid Bodies from Chikungunya Virus

Chikungunya virus (CHIKV) is an alphavirus that causes febrile illness punctuated by severe polyarthralgia. After the emergence of CHIKV in the Western Hemisphere, multiple reports of congenital infections were published that documented neurological complications, cardiac defects, respiratory distress, and miscarriage. The Western Hemisphere is endemic to several alphaviruses, and whether antigenic cross-reactivity can impact the course of infection has not been explored. Recent advances in biomedical engineering have produced cell co-culture models that replicate the cellular interface at the maternal fetal axis. We employed a trans-well assay to determine if cross-reactive antibodies affected the movement and replication of CHIKV across placental cells and into an embryoid body. The data showed that antibodies to Venezuelan equine encephalitis virus significantly reduced CHIKV viral load in embryoid bodies. The data highlighted the fact that viral pathogenesis can be cell-specific and that exploiting antigenic cross-reactivity could be an avenue for reducing the impact of congenital CHIKV infections.

Seroprevalence of yellow fever, dengue, West Nile and chikungunya viruses in children in Teso South Sub-County, Western Kenya

BACKGROUND

Arboviruses often cause widespread morbidity in children in endemic regions. Data on the burden of arboviruses in Kenyan children are limited.

OBJECTIVES

This study was performed to determine the seroprevalence of yellow fever (YFV), dengue (DENV), West Nile (WNV), and chikungunya (CHIKV) viruses among children 1-12 years of age at two health facilities in Teso South Sub-County in Western Kenya.

METHODS

In a hospital-based cross-sectional survey, a questionnaire was used to collect socio-demographic information. Serum drawn from the children was tested for IgA/IgM/IgG serocomplex antibodies to selected arboviruses using indirect ELISA and plaque reduction neutralization tests.

RESULTS

A total of 182 (27.7%) of the 656 participants tested were positive for any arbovirus antibody. Of these, 4.4% (29/656) tested positive for YFV, 9.6% (62/649) for WNV, 5.6% (36/649) for CHIKV, 1.4% (5/368) for DENV1, 9% (59/656) for DENV2, and 19.7% (40/203) for DENV3. Neutralizing antibodies to CHIKV were found in 77.8% (42/54) of participants, to YFV in 15.8% (3/19), to DENV2 in 58% (29/50), and to WNV in 8% (1/55). Sex, age, urban residence, schooling, and lack of vaccination were associated with arbovirus exposure.

CONCLUSIONS

This study confirmed that children under 12 years of age in Teso South Sub-County are exposed to ongoing arbovirus infections early in life.

Circulation of Chikungunya virus East-Central-South Africa genotype during an outbreak in 2016-17 in Piaui State, Northeast Brazil

Chikungunya virus (CHIKV) is an arbovirus that emerged in the Americas in 2013. Infection with CHIKV is symptomatic in most of the cases and patients can develop chronic arthralgia that lasts from months to years in over 40% of the cases. The East-Central-South Africa (ECSA) genotype was introduced in Brazil in 2014, in Bahia State. Here we report the circulation of the CHIKV ECSA genotype in Piaui State, Northeast Brazil, during the years 2016-2017. The phylogenetic analysis revealed a single introduction of this lineage probably in 2015 and its maintenance at least until 2017. This analysis has also demonstrated the proximity of this genotype with isolates from neighboring States, and its partial nucleotide sequence of the viral E1 gene revealed a synapomorphy synonyms. This finding highlights the spread of the ECSA genotype in Brazil and supports its circulation in the Brazilian Northeast.

Chikungunya chronic disease: a systematic review and meta-analysis

Background

Chikungunya is a mosquito-borne disease caused by an arthritogenic alphavirus, with four genotypes: East Central South African (ECSA), West African, ECSA-diverged or Indian Ocean Lineage (IOL) and Asian lineage. Overall, the disease is self-limited; however, in some patients, joint pain and other non-specific symptoms can last for months or years. This systematic review and meta-analysis aims to estimate the proportion of people that self-report chikungunya-related chronic non-specific symptoms.

Methods

Medline, EMBASE, Global Health Library and Scopus were searched for articles published before March 2017. Case-control, cohort, cross-sectional, clinical trials studies and outcome-independent case series were eligible. It was estimated that the proportion of patients who did not recover, by virus genotype, and by the time between disease onset and assessment of chronic symptoms.

Results

A total of 38 studies were included in the review and 34 in the meta-analysis. Of 6532 chikungunya patients, 3157 did not recover fully after 3 months. The overall no recovery rate associated with chikungunya was 43% (95% CI, 35-52%); Inter-genotype group heterogeneity was observed, the highest prevalence in the ECSA-diverged genotype: 50% (95% CI; 40-60%), followed by the Asian lineage genotype: 36% (95% CI; 20-52%). After 12 months follow-up, the overall no-recovery rate was 21% (95% CI; 19-22%).

Conclusion

The evidence suggests that the prevalence of chronic discomfort associated with chikungunya illness varies by virus lineage. The proportion of people that do not fully recovered after chikungunya was high and, therefore, health authorities must prepare to treat patients with symptoms of long-lasting chikungunya adequately addressing the physical, psychological and social needs.

Autocidal gravid ovitraps protect humans from chikungunya virus infection by reducing Aedes aegypti mosquito populations

Background

Public health responses to outbreaks of dengue, chikungunya, and Zika virus have been stymied by the inability to control the primary vector, Aedes aegypti mosquitos. Consequently, the need for novel approaches to Aedes vector control is urgent. Placement of three autocidal gravid ovitraps (AGO traps) in ~85% of homes in a community was previously shown to sustainably reduce the density of female Ae. aegypti by >80%. Following the introduction of chikungunya virus (CHIKV) to Puerto Rico, we conducted a seroprevalence survey to estimate the prevalence of CHIKV infection in communities with and without AGO traps and evaluate their effect on reducing CHIKV transmission.

Methods and findings

Multivariate models that calculated adjusted prevalence ratios (aPR) showed that among 175 and 152 residents of communities with and without AGO traps, respectively, an estimated 26.1% and 43.8% had been infected with CHIKV (aPR = 0.50, 95% CI: 0.37–0.91). After stratification by time spent in their community, protection from CHIKV infection was strongest among residents who reported spending many or all weekly daytime hours in their community:10.3% seropositive in communities with AGO traps vs. 48.7% in communities without (PR = 0.21, 95% CI: 0.11–0.41). The age-adjusted rate of fever with arthralgia attributable to CHIKV infection was 58% (95% CI: 46–66%). The monthly number of CHIKV-infected mosquitos and symptomatic residents were diminished in communities with AGO traps compared to those without.

Conclusions

These findings indicate that AGO traps are an effective tool that protects humans from infection with a virus transmitted by Ae. aegypti mosquitos. Future studies should evaluate their protective effectiveness in large, urban communities.

Aedes species mosquitos transmit pathogens of public health importance, including dengue, Zika, and chikungunya viruses. No tools exist to control these mosquitos that sustainably and effectively prevent human infections. Autocidal gravid ovitraps (AGO traps) have been shown to sustainably reduce Aedes populations by >80%. After chikungunya virus was introduced into Puerto Rico, we conducted serosurveys in communities with and without AGO traps. We observed a two-fold lower prevalence of chikungunya virus infection among residents of communities with AGO traps compared to communities without. Among infected residents of communities with traps, a significant proportion likely had been infected while outside their community. These findings indicate that AGO traps are an effective tool that protects humans from infection with pathogens transmitted by Aedes mosquitos.

Estimating the cost of illness and burden of disease associated with the 2014-2015 chikungunya outbreak in the U.S. Virgin Islands

Chikungunya virus (CHIKV), an alphavirus that causes fever and severe polyarthralgia, swept through the Americas in 2014 with almost 2 million suspected or confirmed cases reported by April 2016. In this study, we estimate the direct medical costs, cost of lost wages due to absenteeism, and years lived with disability (YLD) associated with the 2014–2015 CHIKV outbreak in the U.S. Virgin Islands (USVI). For this analysis, we used surveillance data from the USVI Department of Health, medical cost data from three public hospitals in USVI, and data from two studies of laboratory-positive cases up to 12 months post illness. On average, employed case-patients missed 9 days of work in the 12 months following their disease onset, which resulted in an estimated cost of $15.5 million. Estimated direct healthcare costs were $2.9 million for the first 2 months and $0.6 million for 3–12 months following the outbreak. The total estimated cost associated with the outbreak ranged from $14.8 to $33.4 million (approximately 1% of gross domestic product), depending on the proportion of the population infected with symptomatic disease, degree of underreporting, and proportion of cases who were employed. The estimated YLDs associated with long-term sequelae from the CHIKV outbreak in the USVI ranged from 599–1,322. These findings highlight the significant economic burden of the recent CHIKV outbreak in the USVI and will aid policy-makers in making informed decisions about prevention and control measures for inevitable, future CHIKV outbreaks.

Chikungunya, a virus carried and transmitted by mosquitoes, causes fever, headache, and severe joint pain in humans that often resolves within 7–10 days. However, a proportion of cases, up to 79% in some outbreaks, report persistent joint pain and chronic inflammatory rheumatism, resulting in decreased quality of life for months to years following initial infection. In 2014, chikungunya virus swept through the Americas, resulting in almost 2 million suspected or confirmed cases reported by April 2016. Previous studies have noted the large resource burden from chikungunya outbreaks, including high healthcare costs, lost wages due to absenteeism, and decreased quality of life for months following infection. Our work aimed to estimate the direct medical costs, cost of lost productivity due to absenteeism, and years lived with disability associated with the chikungunya outbreak in the U.S. Virgin Islands. This information may aid policy-makers in making informed decisions about prevention and control measures for inevitable, future chikungunya outbreaks.

Emergence and treatment of chikungunya arthritis

PURPOSE OF REVIEW

To review the emergence, clinical features, pathogenesis, and treatment of acute chikungunya (CHIK) fever and chronic CHIK arthritis.

RECENT FINDINGS

Since 2004, CHIK, an arboviral infection, has spread throughout the world, infecting millions of people. The illness occurs in two phases: an acute viremic infection followed by chronic arthritis. In less developed countries, there are limited resources and effective treatment. For acutely ill CHIK fever patients, management is symptomatic. The treatment of chronic CHIK arthritis should be determined by an understanding of pathogenesis. Is chronic CHIK arthritis a persistent viral infection or a postinfectious inflammatory process? Multiple proinflammatory cytokines, chemokines, and growth factors have been identified in chronic CHIK arthritis. Attempts to isolate CHIK virus from synovial fluid have been unsuccessful. Given pathogenetic similarities (as well as differences) compared with rheumatoid arthritis and the painful, disabling nature of the arthritis, it is not surprising that disease-modifying antirheumatic drugs such as methotrexate have begun to be used.

SUMMARY

CHIK infection has emerged with major arthritic epidemics for which evidence-based therapy is limited. But there is an opportunity to improve the treatment of chronic CHIK arthritis and, from this disease, to gain understanding of the pathogenesis and treatment of inflammatory arthritis more generally.

Risk factors for hospitalization of patients with chikungunya virus infection at sentinel hospitals in Puerto Rico

Background

Hospitalization of patients during outbreaks of chikungunya virus has been reported to be uncommon (0.5–8.7%), but more frequent among infants and the elderly. CHIKV was first detected in Puerto Rico in May 2014. We enrolled patients with acute febrile illness (AFI) presenting to two hospital emergency departments in Puerto Rico and tested them for CHIKV infection to describe the frequency of detection of CHIKV-infected patients, identify risk factors for hospitalization, and describe patients with severe manifestations.

Methodology/Principal findings

Serum specimens were collected from patients with AFI and tested by rRT-PCR. During May–December 2014, a total of 3,035 patients were enrolled, and 1,469 (48.4%) had CHIKV infection. A total of 157 (10.7%) CHIKV-infected patients were hospitalized, six (0.4%) were admitted to the intensive care unit, and two died (0.1%). Common symptoms among all CHIKV-infected patients were arthralgia (82.6%), lethargy (80.6%), and myalgia (80.5%). Compared to patients aged 1–69 years (7.3%), infant (67.2%) and elderly (17.3%) patients were nine and two times more likely to be hospitalized, respectively (relative risk [RR] and 95% confidence interval [CI] = 9.16 [7.05–11.90] and 2.36 [1.54–3.62]). Multiple symptoms of AFI were associated with decreased risk of hospitalization, including arthralgia (RR = 0.31 [0.23–0.41]) and myalgia (RR = 0.29 [0.22–0.39]). Respiratory symptoms were associated with increased risk of hospitalization, including rhinorrhea (RR = 1.68 [1.24–2.27) and cough (RR = 1.77 [1.31–2.39]). Manifestations present among <5% of patients but associated with patient hospitalization included cyanosis (RR = 2.20 [1.17–4.12) and seizures (RR = 3.23 [1.80–5.81).

Discussion

Among this cohort of CHIKV-infected patients, hospitalization was uncommon, admission to the ICU was infrequent, and death was rare. Risk of hospitalization was higher in patients with symptoms of respiratory illness and other manifestations that may not have been the result of CHIKV infection.

Chikungunya is an emerging infectious disease caused by a virus (chikungunya virus, CHIKV) transmitted through the bite of infected mosquitos; typical symptoms are fever and joint pain. After CHIKV was first detected in Puerto Rico in 2014, an epidemic quickly spread across the island. Because previous reports identified varying frequencies of hospitalization of CHIKV-infected patients, we used an existing hospital-based disease detection system to better understand the frequency and reasons for hospitalization of CHIKV-infected patients in Puerto Rico. Among 1,469 patients with laboratory-confirmed CHIKV infection, 11% were hospitalized, most of whom were infants or elderly. Six CHIKV-infected patients were admitted to the intensive care unit, and two died. Although several illness characteristics were associated with hospitalization, most of these were not typical of chikungunya and instead suggested underlying or concomitant respiratory disease. By enrolling patients when they presented to the emergency department and testing them for evidence of CHIKV infection, we determined that hospitalization in this population occurred in roughly one-in-ten CHIKV-infected patients, one-in-two hundred were admitted to the intensive care unit, and one-in-one thousand died. These findings provide information on the spectrum of disease caused by CHIKV, and identified underlying or concomitant respiratory illness as a risk factor associated with hospitalization.

Incidence of articular pain and arthritis after chikungunya fever in the Americas: A systematic review of the literature and meta-analysis

OBJECTIVE

To estimate the incidence of chronic articular symptoms after chikungunya virus infection of patients from the American continent.

METHODS

We performed a systematic review of the literature using the MEDLINE, Web of Science and Scopus databases. We included only cohort studies conducted in the American continent reporting the incidence of chronic articular symptoms after chikungunya virus acute infection. The quality of the selected studies was evaluated through the Newcastle-Ottawa Scale for non-randomized studies and relevant data were extracted. The pooled incidence of post-chikungunya chronic symptoms was estimated using a random-effect model meta-analysis. Heterogeneity was assessed by Q of Cochrane and its P-value, Tau² and I². Subgroup analysis was performed, and studies were stratified by quality, sample size, region, country, period of follow-up and study design.

RESULTS

Up to February 24, 2018, a total of 1115 potentially relevant studies were identified through our search strategy. After exclusion of 226 duplicates and 845 irrelevant studies, we retrieved 41 articles for full-text appreciation, from which 18 studies met our inclusion criteria and were included in this systematic review. Our meta-analysis suggests that 52% of the patients infected with the chikungunya virus will present chronic articular symptoms, although a high heterogeneity between studies was also found (I² = 94%).

CONCLUSION

Fifty-two percent of chikungunya infected patients in the American continent are expected to develop the chronic stage of the disease. Chikungunya fever needs to be dealt as a major world health problem.

Occurrence of Chronic Stage Chikungunya in the General Population of Martinique during the First 2014 Epidemic: A Prospective Epidemiological Study

Chronic stage chikungunya (CHIK), defined by persisting symptoms more than 3 months after initial diagnosis of acute infection, is frequent. However, its burden and impact have rarely been described prospectively in a general population during an ongoing epidemic in the Caribbean. From January 2014 to January 2015, a severe CHIK outbreak occurred in Martinique. Our objective was to describe epidemiological characteristics and outcomes of chronic stage CHIK in its local population. Participants, clinically diagnosed with probable CHIK infection, were included prospectively by general practitioners during the epidemic's peak from April to October 2014. All identified cases benefited from a follow-up phone call 3 months or more after initial diagnosis during which they were interrogated about persisting clinical signs, past and ongoing treatment, and quality of life. Five hundred and nine subjects participated in the study. Mean age at initial diagnosis was 43.2 ± 23.6 years with a female-male ratio of 1.98. Two hundred participants (39.3%) had probable chronic stage CHIK: 98.5% still experienced pain at least 3 months after acute infection, with 84.3% of reported joint pains; 21.2% were woken up by the pain; 47.2% felt depressed/anxious; and 31.3% experienced memory/concentration disorders. Resumption of daily activity and work was complicated for 55.8% and 36.2% of cases. Persistent impact on morbidity, health outcomes, psychological, and economic aspects further underline the crucial role of community-based medicine and the necessity of an evidence-based multidisciplinary approach toward chronic stage CHIK identification, management, and follow-up in this particular world region.

Treatment of chikungunya musculoskeletal disorders: a systematic review

INTRODUCTION

Chikungunya virus is amongst the fastest expanding vector transmissible diseases in recent years and has been causing massive epidemics in Africa, Asia, Latin America and the Caribbean. Despite human infection by this virus being first described in the 1950s, there is a lack of adequate therapeutic evaluations to guide evidence-based recommendations. The current guidelines rely heavily in specialists' opinion and experience instead of using higher rated evidence. Areas covered: A systematic review of the literature was performed- not restricted to clinical trials - reporting the therapeutic response against this infection with the intent to gather the best evidence of the treatment options against musculoskeletal disorders following chikungunya fever. The 15 studies included in the analysis were categorized considering the initiation of treatment during the acute, subacute and chronic phase. Expert commentary: This review demonstrates the complexity of chikungunya fever and difficulty of therapeutic management. This review found no current evidence-based treatment recommendations for the musculoskeletal disorders following chikungunya fever. To provide an optimal treatment that prevents perpetuation or progression of chikungunya infection to a potentially destructive and permanent condition without causing more harm is an aim that must be pursued by researchers and health professionals working with this disease.

Heterogeneity of clinical isolates of chikungunya virus and its impact on the responses of primary human fibroblast-like synoviocytes

Low-passage clinical isolates of chikungunya virus (CHIKV) were found to be a mixture of large- and small-plaque viruses, with small-plaque viruses being the predominant species. To investigate the contribution of plaque variants to the pathology of the joint, primary human fibroblast-like synoviocytes (HFLS) were used. Large- and small-plaque viruses were purified from two clinical isolates, CHIKV-031C and CHIKV-033C, and were designated CHIKV-031L and CHIKV-031S and CHIKV-033L and CHIKV-033S, respectively. The replication efficiencies of these viruses in HFLSs were compared and it was found that CHIKV-031S and CHIKV-033S replicated with the highest efficiency, while the parental clinical isolates had the lowest efficiency. Interestingly, the cytopathic effects (CPE) induced by these viruses correlated with neither the efficiency of replication nor the plaque size. The small-plaque viruses and the clinical isolates induced cell death rapidly, while large-plaque viruses induced slow CPE in which only 50 % of the cells in infected cultures were rounded up and detached on day 5 of infection. The production of proinflammatory cytokines and chemokines from infected HFLSs was evaluated. The results showed that the large-plaque viruses and the clinical isolates, but not small-plaque variants, were potent inducers of IL-6, IL-8 and MCP-1, and were able to migrate monocytes/macrophages efficiently. Sequencing data revealed a number of differences in amino acid sequences between the small- and large-plaque viruses. The results suggest that it is common for clinical isolates of CHIKV to be heterogeneous, while the variants may have distinct roles in the pathology of the joint.

The Identification of Risk Factors for Chronic Chikungunya Arthralgia in Grenada, West Indies: A Cross-Sectional Cohort Study

Background

Chikungunya virus (CHIKV) is a re-emerging arboviral pathogen. In 2014, an explosive CHIKV outbreak occurred in Grenada, West Indies, infecting approximately 60% of the population. In approximately 50% of cases, CHIKV infection transitions to painful arthralgia that can persist for years. Elucidation of the risk factors for chronic disease is imperative to the development of effective risk management strategies and specific therapeutics.

Methods

We conducted a cross-sectional study of 240 people who were tested for CHIKV during the outbreak. We administered questionnaires to examine demographic, behavioral, psychological, social, and environmental factors to identify associations with chronic disease. Physical examinations were performed and persistent symptoms were recorded.

Results

Ethnicity and socioeconomic status were not associated with risk of chronic joint pain. Female sex increased risk, and age was demonstrated to be predictive of chronic CHIKV sequelae. Mosquito avoidance behaviors did not reduce risk. Patients suffering joint pains, generalized body ache, and weakness in the extremities during acute infection were more likely to develop chronic arthralgia, and an increased duration of acute disease also increased risk.

Conclusions

These data demonstrate that chronic CHIKV affects people across the ethnic and socioeconomic spectrum, and it is not reduced by vector avoidance activity. Increased duration of acute symptoms, in particular acute joint pain, was strongly correlated with the risk of persistent arthralgia, thus effective clinical management of acute CHIKV disease could reduce burden of chronic CHIKV.

Serological and spatial analysis of alphavirus and flavivirus prevalence and risk factors in a rural community in western Kenya

Alphaviruses, such as chikungunya virus, and flaviviruses, such as dengue virus, are (re)-emerging arboviruses that are endemic in tropical environments. In Africa, arbovirus infections are often undiagnosed and unreported, with febrile illnesses often assumed to be malaria. This cross-sectional study aimed to characterize the seroprevalence of alphaviruses and flaviviruses among children (ages 5-14, n = 250) and adults (ages 15 ≥ 75, n = 250) in western Kenya. Risk factors for seropositivity were explored using Lasso regression. Overall, 67% of participants showed alphavirus seropositivity (CI95 63%-70%), and 1.6% of participants showed flavivirus seropositivity (CI95 0.7%-3%). Children aged 10-14 were more likely to be seropositive to an alphavirus than adults (p < 0.001), suggesting a recent transmission period. Alphavirus and flavivirus seropositivity was detected in the youngest participants (age 5-9), providing evidence of inter-epidemic transmission. Demographic variables that were significantly different amongst those with previous infection versus those without infection included age, education level, and occupation. Behavioral and environmental variables significantly different amongst those in with previous infection to those without infection included taking animals for grazing, fishing, and recent village flooding. Experience of recent fever was also found to be a significant indicator of infection (p = 0.027). These results confirm alphavirus and flavivirus exposure in western Kenya, while illustrating significantly higher alphavirus transmission compared to previous studies.

Management of chikungunya arthritis

Chikungunya fever (CHIKF) is an emerging viral infection that has spread widely, along with its Aedes vectors, throughout the tropics and beyond, causing explosive epidemics of both acute illness and persistent disabling arthritis. There is an urgent need to mitigate the devastating impact of this illness, through vector control, personal protection, and possibly vaccine development. There is also a need to improve treatment for both acute illness and chronic arthritis. In this review, we will review the emergence of CHIK, what is known about pathogenesis and clinical manifestations, and then focus on current understanding of how to treat individual patients, in particular, those who develop chronic arthritis.