Clinical and epidemiologic characteristics associated with dengue fever in Mombasa, Kenya

Dengue in Pune city, India (2017-2019): a comprehensive analysis

Objectives

To understand the dynamics of dengue disease with special reference to (1) age (2) primary/secondary infections (3) serostatus and (4) serotypes examined during three consecutive years.

Methods

During 3 dengue seasons (2017-19), NS1/IgM ELISAs were used for dengue diagnosis in one of the 15 administrative wards of Pune City, India. Predefined symptoms were recorded at the time of diagnosis/hospitalization. IgG-capture ELISA (Panbio) was used to differentiate primary/secondary infections. DENV serotypes were determined for 260 viral RNA-positive patients.

Results

During the 3 years, 3,014/6,786 (44.4%, 41.4-49.9%) suspected cases were diagnosed as dengue. Use of either NS1 or IgM would have missed 25.5% or 43% of the confirmed dengue cases, respectively. Notably, a higher proportion of secondary dengue cases remained mild while a substantial proportion of primary infections developed warning signs. The symptoms among Dengue/non-dengue patients and primary/secondary infections varied and influenced by age and serostatus. The number and proportion of dengue serotypes varied yearly. A remarkable decline in dengue cases was observed during the COVID-19 pandemic years.

Conclusion

A substantial proportion of primary and secondary dengue patients progress to warning signs/severity or mild infection respectively, underscoring the possible role of non-ADE mechanisms in causing severe dengue that requires hospitalization. Both NS1 and IgM should be used for efficient diagnosis.

Primary Dengue and Long-Term Health Status in Madeira Island, Portugal: A Retrospective Questionnaire-Based Study

Dengue is among the most important mosquito-borne viral diseases worldwide. Although its acute manifestations are well known, little is known about the long-term impact of dengue on the population's health status. Madeira Island experienced a single outbreak of autochthonous dengue from September 2012 to March 2013. To extend our knowledge about the clinical impact of the outbreak on this naive population, we applied an online questionnaire to 168 adults diagnosed with dengue at the time to characterize retrospectively their symptoms during the infection and to identify long-term manifestations, possibly triggered by dengue. The most frequent symptoms during the clinical period, reported by more than three-quarters of our participants, were fever, myalgia, extreme tiredness, and headaches, whereas vomiting, pruritus, nausea, retro-orbital pain, and arthralgia occurred in 35% to 50% of participants. In the 8 years after dengue, 61.5% of participants reported at least one recurrent previously nonexistent symptom, the most frequent being headaches, abundant hair loss, extreme tiredness, arthralgia, and myalgia, experienced by 25% to 35% of participants. Nearly 20% of the participants with persistent symptoms reported the onset of chronic illness in the 4 years after dengue, most frequently ophthalmological and autoimmune diseases (5.6% each), versus only 2.2% of chronic disease onset in participants without persistent symptoms. Our results suggest that the occurrence of persistent symptoms after primary dengue might be more frequent than anticipated and may persist for several years, having an impact on the health status and well-being of a considerable proportion of the infected population.

Acute febrile illness in Kenya: Clinical characteristics and pathogens detected among patients hospitalized with fever, 2017-2019

Acute febrile illness (AFI) is a common reason for healthcare seeking and hospitalization in Sub-Saharan Africa and is often presumed to be malaria. However, a broad range of pathogens cause fever, and more comprehensive data on AFI etiology can improve clinical management, prevent unnecessary prescriptions, and guide public health interventions. We conducted surveillance for AFI (temperature ≥38.0°C <14 days duration) among hospitalized patients of all ages at four sites in Kenya (Nairobi, Mombasa, Kakamega, and Kakuma). For cases of undifferentiated fever (UF), defined as AFI without diarrhea (≥3 loose stools in 24 hours) or lower respiratory tract symptoms (cough/difficulty breathing plus oxygen saturation <90% or [in children <5 years] chest indrawing), we tested venous blood with real-time PCR-based TaqMan array cards (TAC) for 17 viral, 8 bacterial, and 3 protozoal fever-causing pathogens. From June 2017 to March 2019, we enrolled 3,232 AFI cases; 2,529 (78.2%) were aged <5 years. Among 3,021 with outcome data, 131 (4.3%) cases died while in hospital, including 106/2,369 (4.5%) among those <5 years. Among 1,735 (53.7%) UF cases, blood was collected from 1,340 (77.2%) of which 1,314 (98.1%) were tested by TAC; 715 (54.4%) had no pathogens detected, including 147/196 (75.0%) of those aged <12 months. The most common pathogen detected was Plasmodium, as a single pathogen in 471 (35.8%) cases and in combination with other pathogens in 38 (2.9%). HIV was detected in 51 (3.8%) UF cases tested by TAC and was most common in adults (25/236 [10.6%] ages 18-49, 4/40 [10.0%] ages ≥50 years). Chikungunya virus was found in 30 (2.3%) UF cases, detected only in the Mombasa site. Malaria prevention and control efforts are critical for reducing the burden of AFI, and improved diagnostic testing is needed to provide better insight into non-malarial causes of fever. The high case fatality of AFI underscores the need to optimize diagnosis and appropriate management of AFI to the local epidemiology.

Retrospective study on the dengue fever outbreak in Puntland State, Somalia

BACKGROUND

Dengue infection is a mosquito-borne, endemic viral disease, particularly in developing countries. Here, we report the results of the clinicodemographic, serologic profile and the monthly occurrence of a recent dengue fever outbreak in Puntland State (Somalia).

METHODOLOGY

We analyzed the data of 956 dengue-suspected patients who were investigated using the rapid diagnostic testing (RDT) method for detecting NS1 (dengue virus non-structural protein) and IgM antibodies employing the SD Biosensor Dengue Dou NS Ag and IgM test kit (Germany) at the Puntland Public Health Referral Laboratory from November 21, 2022, to May 27, 2023.

RESULTS

We found that 118 cases were positive for dengue among the suspected patients enrolled in the present study. Of these cases, 76.2% were dengue NSI positive, 13.6% were dengue IgM positive, and 10.2% were both NSI and IgM positive. The number of females and males in the confirmed cases was equal, and most (48.3%) were aged 20 years or less. 43.1% of them lived in the Nugal region, particularly in Garowe. Clinically, fever was the most frequent symptom (88.9%). The cases peaked in December 2022 but dropped from January to March, with a slight rise in February, and then increased in April and May 2023.

CONCLUSION

This study highlights the clinicodemographic characteristics, seroprevalence, and monthly occurrence of dengue in Puntland. We recommend improving vector control measures, enhancing case management, strengthening dengue surveillance, developing an early warning system, and conducting future studies to characterize the circulating strains.

Trends in emerging vector-borne viral infections and their outcome in children over two decades

This review utilizes quatitative methods and bibliometric data to analyse the trends of emerging and re-emerging vector-borne diseases, with a focus on their impact on pediatric population. To conduct this analysis, a systematic search of PubMed articles from the past two decades was performed, specifically looking at 26 different vector-borne viruses listed in WHO and CDC list of vector-borne viruses. The review found that diseases like Dengue, Zika, West Nile, and Chikungunya were frequently discussed in the literature. On the other hand, diseases such as Tick-borne encephalitis, Rift Valley fever, Venezuelan equine encephalitis, Sindbis fever, Venezuelan equine encephalitis, Ross River virus, and Eastern equine encephalitis showed an upward trend in publications, indicating potential resurgence. In addition to discussing trends and patterns, the review delves into the clinical manifestations and long-term effects of the top 10 viruses in children. It highlights various factors including deforestation, urbanization, global travel, and immunosuppression that contribute to disease emergence and resurgence. To effectively combat these vector-borne diseases, continuous surveillance is crucial. The review also emphasizes the importance of increased vaccination efforts and targeted research to address the health challenges they pose. IMPACT: This review employs quantitative analysis of publications to elucidate trends in emerging pediatric vector-borne viral diseases over two decades. Dengue, the most prevalent of these diseases, has spread to new regions. New strains of Japanese Encephalitis have caused outbreaks. Resurgence of Tick-borne Encephalitis, West Nile, and Yellow Fever due to vaccine hesitancy has also transpired. Continuous global surveillance, increased vaccination, and research into novel therapeutics are imperative to combat the substantial morbidity and mortality burden these diseases pose for children worldwide.

Seroprevalence of Dengue and Chikungunya Virus Infections in Children Living in Sub-Saharan Africa: Systematic Review and Meta-Analysis

Dengue and chikungunya viruses are frequent causes of malarial-like febrile illness in children. The rapid increase in virus transmission by mosquitoes is a global health concern. This is the first systematic review and meta-analysis of the childhood prevalence of dengue and chikungunya in Sub-Saharan Africa (SSA). A comprehensive search of the MEDLINE (Ovid), Embase (Ovid), and Cochrane Library (Wiley) databases was conducted on 28 June 2019, and updated on 12 February 2022. The search strategy was designed to retrieve all articles pertaining to arboviruses in SSA children using both controlled vocabulary and keywords. The pooled (weighted) proportion of dengue and chikungunya was estimated using a random effect model. The overall pooled prevalence of dengue and chikungunya in SSA children was estimated to be 16% and 7%, respectively. Prevalence was slightly lower during the period 2010-2020 compared to 2000-2009. The study design varied depending on the healthcare facility reporting the disease outbreak. Importantly, laboratory methods used to detect arbovirus infections differed. The present review documents the prevalence of dengue and chikungunya in pediatric patients throughout SSA. The results provide unprecedented insight into the transmission of dengue and chikungunya viruses among these children and highlight the need for enhanced surveillance and controlled methodology.

Detection of acute dengue virus infection, with and without concurrent malaria infection, in a cohort of febrile children in Kenya, 2014-2019, by clinicians or machine learning algorithms

Poor access to diagnostic testing in resource limited settings restricts surveillance for emerging infections, such as dengue virus (DENV), to clinician suspicion, based on history and exam observations alone. We investigated the ability of machine learning to detect DENV based solely on data available at the clinic visit. We extracted symptom and physical exam data from 6,208 pediatric febrile illness visits to Kenyan public health clinics from 2014-2019 and created a dataset with 113 clinical features. Malaria testing was available at the clinic site. DENV testing was performed afterwards. We randomly sampled 70% of the dataset to develop DENV and malaria prediction models using boosted logistic regression, decision trees and random forests, support vector machines, naïve Bayes, and neural networks with 10-fold cross validation, tuned to maximize accuracy. 30% of the dataset was reserved to validate the models. 485 subjects (7.8%) had DENV, and 3,145 subjects (50.7%) had malaria. 220 (3.5%) subjects had co-infection with both DENV and malaria. In the validation dataset, clinician accuracy for diagnosis of malaria was high (82% accuracy, 85% sensitivity, 80% specificity). Accuracy of the models for predicting malaria diagnosis ranged from 53-69% (35-94% sensitivity, 11-80% specificity). In contrast, clinicians detected only 21 of 145 cases of DENV (80% accuracy, 14% sensitivity, 85% specificity). Of the six models, only logistic regression identified any DENV case (8 cases, 91% accuracy, 5.5% sensitivity, 98% specificity). Without diagnostic testing, interpretation of clinical findings by humans or machines cannot detect DENV at 8% prevalence. Access to point-of-care diagnostic tests must be prioritized to address global inequities in emerging infections surveillance.

Patterns of Aedes aegypti abundance, survival, human-blood feeding and relationship with dengue risk, Kenya

Dengue virus (DENV) transmission risk is influenced by the bionomic traits of the key vector, Aedes aegypti. We investigated patterns of abundance, survival, and human blood-feeding of Ae. aegypti populations in two environments in Kenya: peri-urban Rabai (coastal Region, dengue-endemic) and rural Kerio Valley (Rift Valley Region, no reported dengue outbreak). In both environments, Ae. aegypti survival (estimated by parity), was inversely correlated with vector abundance, and this was influenced by weather conditions, notably temperature and relative humidity. In Rabai, Ae. aegypti mostly fed on humans (human blood index=51%), a pattern that corroborates with dengue cases in the coastal region. Aedes aegypti additionally, exhibited opportunistic feeding (livestock, rodents, reptiles, birds), suggesting the risk of human exposure to zoonotic pathogens via spillover transmission events aided by the vector. Abundance and human blood-feeding rates were consistently lower in Kerio Valley likely related to the degree of urbanization. Remarkably, the periods of high human feeding in Rabai coincided with high vector survival rates, a trend that could potentially drive intense DENV transmission at certain times of the year. We found a genetic influence of Ae. aegypti on the degree of anthropophagy but this could be influenced by potential seasonal shifts in human feeding. The findings of this study have implications both for DENV transmission risk and vector control strategies, but also in modeling which should integrate vector bionomic factors beyond vector abundance.

Health education impact on knowledge and management of arboviral diseases in Kenya: Evidence from randomised control trials

Communities' knowledge and management strategies are crucial for mitigating and controlling the threat of existing and emerging diseases. In this study, we conducted randomised control trials (RCT) to examine the impact of health education on households' knowledge and management of three Arboviral Diseases (ADs); Rift Valley fever, Chikungunya fever, and Dengue fever in Kenya. The study was based on a sample of 629 households drawn from the three of Kenya's AD hotspot counties; Baringo, Kwale, and Kilifi. Employing a difference-in-difference method, our findings indicate that health education intervention significantly improved households' understanding of ADs transmission modes, causes, and prevention strategies. However, this intervention did not sufficiently influence households' disease management behaviour. We recommend the implementation of community engagement and outreach initiatives which have the potential to drive behavioural changes at the household level, thus enhancing the management and control of ADs in Kenya.

Dengue Fever Outbreak Investigation in Werder Town, Dollo Zone, Somali Region, Ethiopia

Background

Dengue fever (DF) is a mosquito-borne disease caused by the dengue virus. DF is endemic to many tropical and subtropical countries around the world. In Ethiopia, DF emerged in 2013 and caused a serious public health problem.

Objective

We investigated the outbreak to describe by time, place, person, and to identify risk factors associated with the outbreak in Werder town, Dollo Zone, Somali Region, Ethiopia.

Methods

Descriptive and case-control studies (1:2 ratio) were conducted. We used the World Health Organization (WHO) case definition to identify cases in Werder town from December 10, 2020, to January 4, 2021. Controls were selected from the same town that did not suffer from DF. Serum samples were tested by reverse transcription polymerase chain reaction (RT-PCR) to detect the dengue virus and to identify serotypes. A structured questionnaire was used to collect socio-demographic, behavioural, and environmental characteristics.

Results

We identified a total of 57 cases and 114 controls. The overall attack rate was 334.41/100,000 with a zero case fatality rate. Six out of twenty serum samples tested positive for the DEN-3 serotype. In multivariate analysis, not hearing of DF (Adjusted odd ratio (AOR): 2.2, 95% CI: 1.015-4.701), not knowing the mode of transmission (AOR: 2.9, 95% CI: 1.338-6.831), not using long-lasting insecticidal net (LLITN) (AOR: 4.4, 95% CI: 1.592-12.330) and not spraying insecticide (AOR: 3.6, 95% CI: 1.591-8.098) were statistically significant risk factors associated with DF outbreak. However, wearing long sleeves (AOR: 0.435, 95% CI: 0.206-0.918) was a protective factor for the DF outbreak.

Conclusion

DF outbreak in Werder town has been confirmed. The present study provides evidence-based information regarding the identified risk factors that have contributed to the occurrence of DF outbreaks. We recommended implementing vector control measures and strengthening dengue surveillance systems is strongly advised.

Uncovering the Burden of Dengue in Africa: Considerations on Magnitude, Misdiagnosis, and Ancestry

Dengue is a re-emerging neglected disease of major public health importance. This review highlights important considerations for dengue disease in Africa, including epidemiology and underestimation of disease burden in African countries, issues with malaria misdiagnosis and co-infections, and potential evidence of genetic protection from severe dengue disease in populations of African descent. The findings indicate that dengue virus prevalence in African countries and populations may be more widespread than reported data suggests, and that the Aedes mosquito vectors appear to be increasing in dissemination and number. Changes in climate, population, and plastic pollution are expected to worsen the dengue situation in Africa. Dengue misdiagnosis is also a problem in Africa, especially due to the typical non-specific clinical presentation of dengue leading to misdiagnosis as malaria. Finally, research suggests that a protective genetic component against severe dengue exists in African descent populations, but further studies should be conducted to strengthen this association in various populations, taking into consideration socioeconomic factors that may contribute to these findings. The main takeaway is that Africa should not be overlooked when it comes to dengue, and more attention and resources should be devoted to this disease in Africa.