Risk factors for death among patients with Chikungunya virus infection during the outbreak in northeast Brazil, 2016-2017

A spatial analysis of co-circulating dengue and chikungunya virus infections during an epidemic in a region of Northeastern Brazil

The aim of this study was to describe, through spatial analysis, the cases of arboviruses (dengue and chikungunya), including deaths, during the first epidemic after the circulation of the chikungunya virus (CHIKV) in the state of Pernambuco, Northeastern Brazil. This was an ecological study in both Pernambuco and the state capital, Recife, from 2015 to 2018. The odds ratios (OR) were estimated, and the statistical significance was considered p≤0.05. For the spatial analysis, Kulldorff's space-time scan statistics method was adopted to identify spatial clusters and to provide the relative risk (RR). In order to assess the significance at a level of p < 0.01 of the model, the number of Monte Carlo replications was 999 times. To perform the scan statistics we used the Poisson probability model, with a circular scanning window; annual temporal precision and retrospective analysis. A total of 227 deaths and 158,728 survivors from arboviruses was reported during the study period, with 100 deaths from dengue and 127 from CHIKV. The proportion of deaths from dengue was 0.08% and from chikungunya was 0.35%. The proportion of all those infected (deaths plus survivors) with dengue was 77.42% and with chikungunya was 22.58%. Children aged 0 to 9 years were around 3 times more likely to die than the reference group (OR 2.84; CI95% 1.16-5.00). From the age of 40, the chances of death increased significantly: 40-49 (OR 2.52; CI95% 1.19-5.29), 50-59 (OR 5.55; CI95% 2.76-11.17) and 60 or more (OR 14.90; CI95% 7.79-28.49). Males were approximately twice as likely to die as females (OR 1.77; CI95% 1.36-2.30). White-skinned people were less likely to die compared to non-white (OR 0.60; CI95% 0.41-0.87). The space-time analysis of prevalence in the state of Pernambuco revealed the presence of four clusters in the years 2015 and 2016, highlighting the Metropolitan Macro-region with a relative risk=4 and the Agreste and Hinterland macro-regions with a relative risk=3.3. The spatial distribution of the death rate in the municipality of Recife smoothed by the local empirical Bayesian estimator enabled a special pattern to be identified in the southwest and northeast of the municipality. The spatiotemporal analysis of the death rate revealed the presence of two clusters in the year 2015. In the primary cluster, it may be noted that the aforementioned aggregate presented a RR=7.2, and the secondary cluster presented a RR=6.0. The spatiotemporal analysis with Kulldorff's space-time scan statistics method, proved viable in identifying the risk areas for the occurrence of arboviruses, and could be included in surveillance routines so as to optimize prevention strategies during future epidemics.

Factors associated with death from dengue and chikungunya virus infection during an epidemic period in Northeast Brazil: A retrospective cohort study

BACKGROUND

We investigated the time to death and factors associated with deaths from dengue and chikungunya during the first epidemic after the introduction of the chikungunya virus in Northeastern Brazil.

METHODS

This retrospective cohort study was conducted in Pernambuco between 2015 and 2018. Logistic regression was used to identify independent risk factors. The probability of survival among individuals with different arbovirus infections was estimated and the survival curves were compared using log-rank tests.

RESULTS

The lethality coefficients for dengue and chikungunya viruses were 0.08% and 0.35%, respectively. The chance of death due to chikungunya infection increased progressively from the age of 40 years. At 40-49 years, the odds ratio was 13.83 (95%CI, 1.80-106.41). At 50-59 years and 60 years or older, the odds ratio was 27.63 (95%CI, 3.70-206.48); and 78.72 (95%CI, 10.93-566.90), respectively. The probability of death associated with dengue virus infection increased from the age of 50 years. Among patients aged 50-59 years and 60 years or older, the odds ratio was 4.30 (95%CI, 1.80-10.30) and 8.97 (95%CI, 4.00-20.0), respectively. Independent factors associated death were headache and age of 50 years or older for dengue; and headache, nausea, back pain, intense arthralgia, age 0-9 years or 40 years and older, and male sex for chikungunya. The ratio between mortality rates revealed that the time to death from dengue was 2.1 times faster than that from chikungunya (95%CI, 1.57-2.72).

CONCLUSIONS

The time to death was shorter in patients with dengue than in those with chikungunya disease. This study reinforces the need for faster and more effective decision-making in public health services to enhance patient outcomes and minimize mortality.

The research progress of Chikungunya fever

Chikungunya fever, an acute infectious disease caused by Chikungunya virus (CHIKV), is transmitted by Aedes aegypti mosquitoes, with fever, rash, and joint pain as the main features. 1952, the first outbreak of Chikungunya fever was in Tanzania, Africa, and the virus was isolated in 1953. The epidemic has expanded from Africa to South Asia, the Indian Ocean islands and the Americas, and is now present in more than 100 countries and territories worldwide, causing approximately 1 million infections worldwide each year. In addition, fatal cases have been reported, making CHIKV a relevant public health disease. The evolution of the virus, globalization, and climate change may have contributed to the spread of CHIKV. 2005-2006 saw the most severe outbreak on Reunion Island, affecting nearly 35% of the population. Since 2005, cases of Chikungunya fever have spread mainly in tropical and subtropical regions, eventually reaching the Americas through the Caribbean island. Today, CHIKV is widely spread worldwide and is a global public health problem. In addition, the lack of a preventive vaccine and approved antiviral treatment makes CHIKV a major global health threat. In this review, we discuss the current knowledge on the pathogenesis of CHIKV, focusing on the atypical disease manifestations. We also provide an updated review of the current development of CHIKV vaccines. Overall, these aspects represent some of the most recent advances in our understanding of CHIKV pathogenesis and also provide important insights into the current development of CHIKV and potential CHIKV vaccines for current development and clinical trials.

The relationship between chikungunya virus and the kidneys: A scoping review

Several atypical forms of chikungunya fever (CHIK) have been described, including neurological, cardiac and renal involvement. These forms may be related to high morbidity and mortality rates. This scoping review based on the PubMed, Scopus, and WOS databases aims to identify and summarise all the available evidence regarding the clinical and histopathological presentations and risk factors associated with kidney injury related to CHIK, as well as the clinical impact. Thus, a total of 54 papers were selected from 1606 initial references after applying the defined inclusion criteria. Data on the association between kidney injury and CHIK are scarce, with studies only conducted in the acute phase of the disease, lacking further characterisation. Kidney injury incidence in hospitalised patients using the Kidney Disease Improving Global Outcomes criteria varies from 21% to 45%, being higher among patients with atypical and severe manifestations. Although acute kidney injury does not seem to be related to viraemia, it may be related to higher mortality. Few studies have described the renal histopathological changes in the acute phase of CHIK, with prevalent findings of acute interstitial nephritis with mononuclear infiltrate, glomerular congestion and nephrosclerosis. Only one study assessed the kidney function of patients in the subacute and chronic phases of CHIK. Additionally, individuals with comorbidities, including chronic kidney disease, may be among those with a greater risk of presenting worse outcomes when affected by CHIK. The results described herein may contribute to better understand the relationship between the kidneys and chikungunya virus.

Aedes aegypti Shows Increased Susceptibility to Zika Virus via Both In Vitro and In Vivo Models of Type II Diabetes

Chronic conditions like type II diabetes (T2DM) have long been known to exacerbate many infectious diseases. For many arboviruses, including Zika virus (ZIKV), severe outcomes, morbidity and mortality usually only occur in patients with such pre-existing conditions. However, the effects of T2DM and other pre-existing conditions on human blood (e.g., hypo/hyperinsulinemia, hyperglycemia and hyperlipidemia) that may impact infectivity of arboviruses for vectors is largely unexplored. We investigated whether the susceptibility of Aedes aegypti mosquitoes was affected when the mosquitoes fed on “diabetic” bloodmeals, such as bloodmeals composed of artificially glycosylated erythrocytes or those from viremic, diabetic mice (LEPRDB/DB). Increasing glycosylation of erythrocytes from hemoglobin A1c (HgbA1c) values of 5.5–5.9 to 6.2 increased the infection rate of a Galveston, Texas strain of Ae. aegypti to ZIKV strain PRVABC59 at a bloodmeal titer of 4.14 log10 FFU/mL from 0.0 to 40.9 and 42.9%, respectively. ZIKV was present in the blood of viremic LEPRDB/DB mice at similar levels as isogenic control C57BL/6J mice (3.3 log10 FFU/mL and 3.6 log10 FFU/mL, respectively. When mice sustained a higher ZIKV viremia of 4.6 log10 FFU/mL, LEPRDB/DB mice infected 36.3% of mosquitoes while control C57BL/6J mice with a viremia of 4.2 log10 FFU/mL infected only 4.1%. Additionally, when highly susceptible Ae. aegypti Rockefeller mosquitoes fed on homozygous LEPRDB/DB, heterozygous LEPRWT/DB, and control C57BL/6J mice with viremias of ≈ 4 log10 FFU/mL, 54%, 15%, and 33% were infected, respectively. In total, these data suggest that the prevalence of T2DM in a population may have a significant impact on ZIKV transmission and indicates the need for further investigation of the impacts of pre-existing metabolic conditions on arbovirus transmission.

Cardiomyopathy and Death Following Chikungunya Infection: An Increasingly Common Outcome

Chikungunya virus (CHIKV) is vectored by Aedes aegypti and Aedes albopictus mosquitoes and is found throughout tropical and sub-tropical regions. While most infections cause mild symptoms such as fever and arthralgia, there have been cases in which cardiac involvement has been reported. In adults, case reports include symptoms ranging from tachycardia and arrythmia, to myocarditis and cardiac arrest. In children, case reports describe symptoms such as arrythmia, myocarditis, and heart failure. Case reports of perinatal and neonatal CHIKV infections have also described cardiovascular compromise, including myocardial hypertrophy, ventricular dysfunction, myocarditis, and death. Myocarditis refers to inflammation of the heart tissue, which can be caused by viral infection, thus becoming viral myocarditis. Since viral myocarditis is linked as a causative factor of other cardiomyopathies, including dilated cardiomyopathy, in which the heart muscle weakens and fails to pump blood properly, the connection between CHIKV and the heart is concerning. We searched Pubmed, Embase, LILACS, and Google Scholar to identify case reports of CHIKV infections where cardiac symptoms were reported. We utilized NCBI Virus and NCBI Nucleotide to explore the lineage/evolution of strains associated with these outbreaks. Statistical analysis was performed to identify which clinical features were associated with death. Phylogenetic analysis determined that CHIKV infections with cardiac symptoms are associated with the Asian, the East Central South African, and the Indian Ocean lineages. Of patients admitted to hospital, death rates ranged from 26-48%. Myocarditis, hypertension, pre-existing conditions, and the development of heart failure were significantly correlated with death. As such, clinicians should be aware in their treatment and follow-up of patients.

A clinical scoring system to predict long-term arthralgia in Chikungunya disease: A cohort study

BACKGROUND

Chikungunya virus (CHIKV) has caused worldwide epidemics that impose a major burden on health systems. Approximately half of infected individuals develop chronic debilitating arthralgia, affecting their quality of life. Here, we identified the relevant clinical and demographic variables in the acute phase of CHIKV infection prospectively linked to chronic arthralgia to elaborate a prognostic scoring system.

METHODS

Acute CHIKV infection cases (n = 134) confirmed by serology or molecular test were examined <10 days of disease onset and followed for one year to evaluate for disease progression. Potential risk factors for chronic arthralgia were evaluated by multivariate analysis to develop a prognostic scoring system, which was subsequently tested in an independent validation cohort consisting of 42 individuals.

RESULTS

A total of 107 out of 134 (80%) acute CHIKV-confirmed cases from the derivation cohort were re-examined one year after enrollment. Chronic arthralgia post-CHIKV infection was diagnosed in 64 (60%). Five of the 12 parameters evaluated in the acute phase were statistically associated with persistent arthralgia and were further tested by Bayesian analysis. These variables were weighted to yield a prognosis score denominated SHERA (Sex, Hypertension, Edema, Retroocular pain, Age), which exhibited 81.3% accuracy in predicting long-term arthralgia post-CHIKV infection in the derivation cohort, and 76.5% accuracy in the validation cohort.

CONCLUSIONS

The simplified and externally validated prognostic scoring system, SHERA, is a useful method to screen acutely CHIKV-infected patients at elevated risk of chronic arthralgia who will benefit from specific interventions. This tool could guide public health policies, particularly in resource-constrained settings.

Events preceding death among chikungunya virus infected patients: a systematic review

Since its re-emergence in the late 1990s, there have been reports of Chikungunya fever (CHIK-F) presenting with severe or atypical findings. There is little knowledge regarding the clinical events leading to the death of patients with CHIK-F. This study aimed to systematically review the literature regarding CHIK-F and identify clinical features preceding death. We searched PubMed, Scopus, Embase, Lilacs, and IsiWeb for case-reports, case-series, or cohorts of CHIK-F reporting at least one death, up to December 2019. Fifty-seven reports were analyzed, including 2140 deaths. Data about specific clinical events that precede death are scarce. The central tendency of time between disease onset and death ranged from 2 days to 150 days. The most common clinical findings among decedents were fever (22.0%), arthralgia (15.7%), myalgia (10.7%), and headache (8.2%). Excluding pediatric populations, the reported central tendency of age among the decedents was 53 or older, with a non-weighted median of 67, ranging up to 80 years old. Authors mentioned organic dysfunction in 91.2% reports. Among all the 2140 decedents, the most common dysfunctions were cardiovascular (7.2%), respiratory (6.4%), neurological (5.4%), renal (4.2%), liver (3.0%), and hematological (1.3%) dysfunction. Exacerbation of previous diabetes (5.6%) or hypertension (6.9%) was mentioned as conditions preceding death. Currently, older age, primary neurological, cardiovascular, or respiratory dysfunction and a previous diagnosis of diabetes or hypertension are the main clinical events preceding death.

Mosquito-Borne Diseases Emergence/Resurgence and How to Effectively Control It Biologically

Deadly pathogens and parasites are transmitted by vectors and the mosquito is considered the most threatening vector in public health, transmitting these pathogens to humans and animals. We are currently witnessing the emergence/resurgence in new regions/populations of the most important mosquito-borne diseases, such as arboviruses and malaria. This resurgence may be the consequence of numerous complex parameters, but the major cause remains the mismanagement of insecticide use and the emergence of resistance. Biological control programmes have rendered promising results but several highly effective techniques, such as genetic manipulation, remain insufficiently considered as a control mechanism. Currently, new strategies based on attractive toxic sugar baits and new agents, such as Wolbachia and Asaia, are being intensively studied for potential use as alternatives to chemicals. Research into new insecticides, Insect Growth Regulators, and repellent compounds is pressing, and the improvement of biological strategies may provide key solutions to prevent outbreaks, decrease the danger to at-risk populations, and mitigate resistance.

Estimated mortality rate and leading causes of death among individuals with chikungunya in 2016 and 2017 in Brazil

INTRODUCTION

In 2014, the first cases of autochthonous chikungunya (CHIK) were recorded in Brazil. Lethality associated with this disease is underestimated. Thus, this study aimed to analyze the causes of death among individuals with CHIK in Brazil.

METHODS

A descriptive observational study was conducted on individuals with CHIK who died within 6 months from symptom onset. Data pairing between the Information System for Notifiable Diseases and the Mortality Information System was performed. Deaths were classified according to case confirmation criterion, mention of CHIK in the death certificates (DCs), and disease phase. The lethality rate per 1,000 cases was corrected for underreporting and was estimated according to region, sex, age, years of education, race/color, and cause groups.

RESULTS

We identified 3,135 deaths (mention of CHIK in the DCs, 764 [24.4%]). In 17.6% of these cases, CHIK was the underlying cause. Most deaths occurred in the acute (38.1%) and post-acute (29.6%) phases. The corrected LR (5.7; x1,000) was 6.8 times higher than that obtained from the Information System for Notifiable Diseases (0.8). The highest corrected LRs were estimated for among individuals living in the Northeast region (6.2), men (7.4), those with low years of education and those aged <1 year (8.6), 65-79 years (20.7), and ≥80 years (75.4).

CONCLUSIONS

The LR of CHIK estimates based on information system linkage help to reveal the relevance of this disease as the direct cause or as a cause associated with serious or fatal events, provide timely interventions, and increase the knowledge about this disease.