Tropical Medicine and Infectious Disease

Research

16 pages, 2295 KiB

Open AccessArticle

Genetic Diversity of Dengue Virus in Clinical Specimens from Bangkok, Thailand, during 2018–2020: Co-Circulation of All Four Serotypes with Multiple Genotypes and/or Clades

by Kanaporn Poltep, Juthamas Phadungsombat, Emi E. Nakayama, Nathamon Kosoltanapiwat, Borimas Hanboonkunupakarn, Witthawat Wiriyarat, Tatsuo Shioda and Pornsawan Leaungwutiwong

Trop. Med. Infect. Dis. 2021, 6(3), 162; https://doi.org/10.3390/tropicalmed6030162 - 4 Sep 2021

Cited by 14 | Viewed by 5228

Abstract

Dengue is an arboviral disease highly endemic in Bangkok, Thailand. To characterize the current genetic diversity of dengue virus (DENV), we recruited patients with suspected DENV infection at the Hospital for Tropical Diseases, Bangkok, during 2018–2020. We determined complete nucleotide sequences of the [...] Read more.

Dengue is an arboviral disease highly endemic in Bangkok, Thailand. To characterize the current genetic diversity of dengue virus (DENV), we recruited patients with suspected DENV infection at the Hospital for Tropical Diseases, Bangkok, during 2018–2020. We determined complete nucleotide sequences of the DENV envelope region for 111 of 276 participant serum samples. All four DENV serotypes were detected, with the highest proportion being DENV-1. Although all DENV-1 sequences were genotype I, our DENV-1 sequences were divided into four distinct clades with different distributions in Asian countries. Two genotypes of DENV-2 were identified, Asian I and Cosmopolitan, which were further divided into two and three distinct clades, respectively. In DENV-3, in addition to the previously dominant genotype III, a cluster of 6 genotype I viruses only rarely reported in Thailand was also observed. All of the DENV-4 viruses belonged to genotype I, but they were separated into three distinct clades. These results indicated that all four serotypes of DENV with multiple genotypes and/or clades co-circulate in Bangkok. Continuous investigation of DENV is warranted to further determine the relationship between DENV within Thailand and neighboring countries in Southeast Asia and Asia. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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9 pages, 942 KiB

Open AccessCommunication

Nationwide Distribution of Dengue Virus Type 3 (DENV-3) Genotype I and Emergence of DENV-3 Genotype III during the 2019 Outbreak in Bangladesh

by Snigdha Rahman Titir, Shyamal Kumar Paul, Salma Ahmed, Nazia Haque, Syeda Anjuman Nasreen, Khondoker Shoaib Hossain, Fahim Uddin Ahmad, Sultana Shabnam Nila, Jobyda Khanam, Neaz Nowsher, Abu Mohammod Mayeenuddin Al Amin, Amdad Ullah Khan, Meiji Soe Aung and Nobumichi Kobayashi

Trop. Med. Infect. Dis. 2021, 6(2), 58; https://doi.org/10.3390/tropicalmed6020058 - 21 Apr 2021

Cited by 13 | Viewed by 3995

Abstract

Bangladesh is an endemic region of dengue fever and experienced an unprecedented large outbreak with more than 100,000 confirmed cases in 2019. To understand the prevalence of dengue antibody in patients and molecular epidemiological characteristics of dengue virus (DENV) in this outbreak, a [...] Read more.

Bangladesh is an endemic region of dengue fever and experienced an unprecedented large outbreak with more than 100,000 confirmed cases in 2019. To understand the prevalence of dengue antibody in patients and molecular epidemiological characteristics of dengue virus (DENV) in this outbreak, a total of 179 blood samples were collected from patients in 10 districts (seven divisions) covering nearly the whole country from August to December 2019. DENV NS-1 was detected in 162 samples, among which DENV-specific IgM was positive in 119 samples (73.5%), including 60.5% samples also positive for DENV-specific IgG. Sequencing of the partial C-prM gene and its phylogenetic analysis revealed predominance of DENV type 3 genotype I, accounting for 93% of samples examined. DENV-3 genotype III was identified in two samples from separate districts, and only one DENV-2 cosmopolitan genotype was found in the capital city, Dhaka. These findings suggest the predominance of DENV-3 genotype I and occurrence of DENV-3 genotype III, associated with increased incidence of recent secondary infection in Bangladesh in 2019. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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12 pages, 4644 KiB

Open AccessArticle

Two Cases of Natural Infection of Dengue-2 Virus in Bats in the Colombian Caribbean

by Alfonso Calderón, Camilo Guzmán, Teresa Oviedo-Socarras, Salim Mattar, Virginia Rodríguez, Víctor Castañeda and Luiz Tadeu Moraes Figueiredo

Trop. Med. Infect. Dis. 2021, 6(1), 35; https://doi.org/10.3390/tropicalmed6010035 - 12 Mar 2021

Cited by 8 | Viewed by 3796

Abstract

Dengue, a mosquito-borne zoonotic disease, is the most common vector-borne disease in tropical and subtropical areas. In this study, we aim to demonstrate biological evidence of dengue virus infection in bats. A cross-sectional study was carried out in the departments of Cordoba and [...] Read more.

Dengue, a mosquito-borne zoonotic disease, is the most common vector-borne disease in tropical and subtropical areas. In this study, we aim to demonstrate biological evidence of dengue virus infection in bats. A cross-sectional study was carried out in the departments of Cordoba and Sucre, Colombia. A total of 286 bats were captured following the ethical protocols of animal experimentation. The specimens were identified and euthanized using a pharmacological treatment with atropine, acepromazine and sodium pentobarbital. Duplicate samples of brain, heart, lung, spleen, liver, and kidney were collected with one set stored in Trizol and the other stored in 10% buffered formalin for histopathological and immunohistochemical analysis using polyclonal antibodies. Brain samples from lactating mice with an intracranial inoculation of DENV-2 were used as a positive control. As a negative control, lactating mouse brains without inoculation and bats brains negative for RT-PCR were included. Tissue sections from each specimen of bat without conjugate were used as staining control. In a specimen of Carollia perspicillata captured in Ayapel (Cordoba) and Phylostomus discolor captured in San Carlos (Cordoba), dengue virus was detected, and sequences were matched to DENV serotype 2. In bats RT-PCR positive for dengue, lesions compatible with viral infections, and the presence of antigens in tissues were observed. Molecular findings, pathological lesions, and detection of antigens in tissues could demonstrate viral DENV-2 replication and may correspond to natural infection in bats. Additional studies are needed to elucidate the exact role of these species in dengue epidemics. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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17 pages, 1300 KiB

Open AccessArticle

Assessing the Risk of Exotic Mosquito Incursion through an International Seaport, Newcastle, NSW, Australia

by Cameron E. Webb, Philippe G. Porigneaux and David N. Durrheim

Trop. Med. Infect. Dis. 2021, 6(1), 25; https://doi.org/10.3390/tropicalmed6010025 - 17 Feb 2021

Cited by 3 | Viewed by 3871

Abstract

Exotic mosquitoes, especially container-inhabiting species such as Aedes aegypti and Aedes albopictus, pose a risk to Australia as they bring with them potentially significant pest and public health concerns. Notwithstanding the threat to public health and wellbeing, significant economic costs associated with [...] Read more.

Exotic mosquitoes, especially container-inhabiting species such as Aedes aegypti and Aedes albopictus, pose a risk to Australia as they bring with them potentially significant pest and public health concerns. Notwithstanding the threat to public health and wellbeing, significant economic costs associated with the burden of mosquito control would fall to local authorities. Detection of these mosquitoes at airports and seaports has highlighted pathways of introduction but surveillance programs outside these first ports of entry are not routinely conducted in the majority of Australian cities. To assist local authorities to better prepare response plans for exotic mosquito incursions, an investigation was undertaken to determine the extent of habitats suitable for container-inhabiting mosquitoes in over 300 residential properties adjacent to the Port of Newcastle, Newcastle, NSW. More than 1500 water-holding containers were recorded, most commonly pot plant saucers, roof gutters, and water-holding plants (e.g., bromeliads). There were significantly more containers identified for properties classified as untidy but there was no evidence visible that property characteristics could be used to prioritise property surveys in a strategic eradication response. The results demonstrate that there is potential for local establishment of exotic mosquitoes and that considerable effort would be required to adequately survey these environments for the purpose of surveillance and eradication programs. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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15 pages, 1609 KiB

Open AccessArticle

Chikungunya Manifestations and Viremia in Patients Who Presented to the Fever Clinic at Bangkok Hospital for Tropical Diseases during the 2019 Outbreak in Thailand

by Hisham A Imad, Juthamas Phadungsombat, Emi E Nakayama, Sajikapon Kludkleeb, Wasin Matsee, Thitiya Ponam, Keita Suzuki, Pornsawan Leaungwutiwong, Watcharapong Piyaphanee, Weerapong Phumratanaprapin and Tatsuo Shioda

Trop. Med. Infect. Dis. 2021, 6(1), 12; https://doi.org/10.3390/tropicalmed6010012 - 21 Jan 2021

Cited by 9 | Viewed by 4199

Abstract

Chikungunya virus is an Alphavirus belonging to the family Togaviridae that is transmitted to humans by an infected Aedes mosquito. Patients develop fever, inflammatory arthritis, and rash during the acute stage of infection. Although the illness is self-limiting, atypical and severe cases are [...] Read more.

Chikungunya virus is an Alphavirus belonging to the family Togaviridae that is transmitted to humans by an infected Aedes mosquito. Patients develop fever, inflammatory arthritis, and rash during the acute stage of infection. Although the illness is self-limiting, atypical and severe cases are not uncommon, and 60% may develop chronic symptoms that persist for months or even for longer durations. Having a distinct periodical epidemiologic outbreak pattern, chikungunya virus reappeared in Thailand in December 2018. Here, we describe a cohort of acute chikungunya patients who had presented to the Bangkok Hospital for Tropical Diseases during October 2019. Infection was detected by a novel antigen kit and subsequently confirmed by real-time RT-PCR using serum collected at presentation to the Fever Clinic. Other possible acute febrile illnesses such as influenza, dengue, and malaria were excluded. We explored the sequence of clinical manifestations at presentation during the acute phase and associated the viral load with the clinical findings. Most of the patients were healthy individuals in their forties. Fever and arthralgia were the predominant clinical manifestations found in this patient cohort, with a small proportion of patients with systemic symptoms. Higher viral loads were associated with arthralgia, and arthralgia with the involvement of the large joints was more common in female patients. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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10 pages, 979 KiB

Open AccessArticle

Risk Factors for Elevated Serum Lipopolysaccharide in Acute Dengue and Association with Clinical Disease Severity

by N. L. Ajantha Shyamali, Sameera D. Mahapatuna, Laksiri Gomes, Ananda Wijewickrama, Graham S. Ogg and Gathsaurie Neelika Malavige

Trop. Med. Infect. Dis. 2020, 5(4), 170; https://doi.org/10.3390/tropicalmed5040170 - 16 Nov 2020

Cited by 8 | Viewed by 3069

Abstract

Although serum lipopolysaccharide (LPS) was shown to associate with development of severe dengue, the reasons for high LPS and its subsequent involvement in disease pathogenesis are not known. We assessed serum LPS, C-reactive protein (CRP), and procalcitonin in patients with acute dengue fever [...] Read more.

Although serum lipopolysaccharide (LPS) was shown to associate with development of severe dengue, the reasons for high LPS and its subsequent involvement in disease pathogenesis are not known. We assessed serum LPS, C-reactive protein (CRP), and procalcitonin in patients with acute dengue fever (DF = 129) and dengue haemorrhagic fever (DHF = 64) and correlated these observations with the presence of comorbid illnesses, and clinical disease severity. Serum LPS levels were significantly (p = 0.01) higher in patients with DHF, compared to those with DF. In total, 45 (70%) of those with DHF and 63 (49%) of those with DF had detectable LPS and therefore, the presence of LPS was significantly associated with DHF (p = 0.005, OR = 2.48, 95% CI: 1.29 to 4.64). Those with metabolic diseases, 22/29 (75.9%) and those with atopic diseases 17/22 (77.3%) were significantly more likely to have detectable LPS levels (p = 0.025, OR = 2.9, 95% CI-1.17 to 7.59 and p = 0.039, OR = 3.06, 95% CI-1.07 to 7.81 respectively). Those with detectable LPS levels were also more likely to develop shock and severe thrombocytopenia. Patients with detectable LPS were more likely to have elevated CRP levels and were more likely to develop DHF. Procalcitonin levels too were significantly (p = 0.009) higher in those with DHF compared to those with DF and were more likely to be high in those with detectable serum LPS. Since serum LPS levels were higher in patients with DHF and significantly more likely to be present in those with comorbid illnesses, the possible role of LPS in disease pathogenesis should be further investigated. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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10 pages, 3079 KiB

Open AccessArticle

Effects of El Niño Southern Oscillation and Dipole Mode Index on Chikungunya Infection in Indonesia

by Harapan Harapan, Amanda Yufika, Samsul Anwar, Haypheng Te, Hamzah Hasyim, Roy Nusa, Pandji Wibawa Dhewantara and Mudatsir Mudatsir

Trop. Med. Infect. Dis. 2020, 5(3), 119; https://doi.org/10.3390/tropicalmed5030119 - 16 Jul 2020

Cited by 6 | Viewed by 3555

Abstract

The aim of this study was to assess the possible association of El Niño Southern Oscillation (ENSO) and Dipole Mode Index (DMI) on chikungunya incidence overtime, including the significant reduction in cases that was observed in 2017 in Indonesia. Monthly nation-wide chikungunya case [...] Read more.

The aim of this study was to assess the possible association of El Niño Southern Oscillation (ENSO) and Dipole Mode Index (DMI) on chikungunya incidence overtime, including the significant reduction in cases that was observed in 2017 in Indonesia. Monthly nation-wide chikungunya case reports were obtained from the Indonesian National Disease Surveillance database, and incidence rates (IR) and case fatality rate (CFR) were calculated. Monthly data of Niño3.4 (indicator used to represent the ENSO) and DMI between 2011 and 2017 were also collected. Correlations between monthly IR and CFR and Niño3.4 and DMI were assessed using Spearman’s rank correlation. We found that chikungunya case reports declined from 1972 cases in 2016 to 126 cases in 2017, a 92.6% reduction; the IR reduced from 0.67 to 0.05 cases per 100,000 population. No deaths associated with chikungunya have been recorded since its re-emergence in Indonesia in 2001. There was no significant correlation between monthly Niño3.4 and chikungunya incidence with r = −0.142 (95%CI: −0.320–0.046), p = 0.198. However, there was a significant negative correlation between monthly DMI and chikungunya incidence, r = −0.404 (95%CI: −0.229–−0.554) with p < 0.001. In conclusion, our initial data suggests that the climate variable, DMI but not Niño3.4, is likely associated with changes in chikungunya incidence. Therefore, further analysis with a higher resolution of data, using the cross-wavelet coherence approach, may provide more robust evidence. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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7 pages, 679 KiB

Open AccessArticle

Performance of an Automated Zika IgG Immunoassay in the Detection of Zika IgG Specific Antibodies—A Validation Approach in Samples from Prevalence Areas and Non-Endemic Countries

by Tina Laengin, Stephanie Augenstein, Elke Stadlbauer, Heike Girgnhuber, Mario Gloeck and Alexander Riedel

Trop. Med. Infect. Dis. 2020, 5(2), 97; https://doi.org/10.3390/tropicalmed5020097 - 8 Jun 2020

Cited by 2 | Viewed by 3044

Abstract

The diagnosis of Zika virus infection is complicated and includes testing for nucleic acids and IgM and IgG antibodies, depending on the stage of infection. Zika IgG is an important marker of infection after the acute stage; however, IgG assays can lack specificity [...] Read more.

The diagnosis of Zika virus infection is complicated and includes testing for nucleic acids and IgM and IgG antibodies, depending on the stage of infection. Zika IgG is an important marker of infection after the acute stage; however, IgG assays can lack specificity due to the similarities between Zika and other flaviviruses. In this study, the diagnostic sensitivity and specificity of the Elecsys^® Zika IgG assay were assessed in 496 samples from Zika endemic regions, and specificity only was assessed in 1685 blood screening and diagnostic samples from Zika non-endemic regions. Cross-reactivity was also assessed against a panel of 202 potentially cross-reacting samples. The performance of the Elecsys^® Zika IgG assay was compared with the anti-Zika virus ELISA IgG. In the samples from the Zika endemic regions, the Elecsys^® Zika IgG assay had 92.88% (95% confidence interval 89.42–95.48) sensitivity and 100% specificity and in the samples from Europe the Elecsys^® Zika IgG assay specificity was ≥99.62%. The Elecsys^® Zika IgG assay was highly specific in samples from both prevalent and non-endemic regions. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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9 pages, 1254 KiB

Open AccessArticle

Monitoring Insecticide Susceptibility in Aedes Aegypti Populations from the Two Biggest Cities, Ouagadougou and Bobo-Dioulasso, in Burkina Faso: Implication of Metabolic Resistance

by Moussa Namountougou, Dieudonné Diloma Soma, Mahamoudou Balboné, Didier Alexandre Kaboré, Mahamadi Kientega, Aristide Hien, Ahmed Coulibaly, Parfait Eric Ouattara, Benson Georges Meda, Samuel Drabo, Lassane Koala, Charles Nignan, Thérèse Kagoné, Abdoulaye Diabaté, Florence Fournet, Olivier Gnankiné and Roch Kounbobr Dabiré

Trop. Med. Infect. Dis. 2020, 5(2), 84; https://doi.org/10.3390/tropicalmed5020084 - 27 May 2020

Cited by 16 | Viewed by 4210

Abstract

In West Africa, Aedes aegypti remains the major vector of dengue virus. Since 2013, dengue fever has been reemerging in Burkina Faso with annual outbreaks, thus becoming a major public health problem. Its control relies on vector control, which is unfortunately facing the [...] Read more.

In West Africa, Aedes aegypti remains the major vector of dengue virus. Since 2013, dengue fever has been reemerging in Burkina Faso with annual outbreaks, thus becoming a major public health problem. Its control relies on vector control, which is unfortunately facing the problem of insecticide resistance. At the time of this study, although data on phenotypic resistance were available, information related to the metabolic resistance in Aedes populations from Burkina Faso remained very scarce. Here, we assessed the phenotypic and the metabolic resistance of Ae. aegypti populations sampled from the two main urban areas (Ouagadougou and Bobo-Dioulasso) of Burkina Faso. Insecticide susceptibility bioassays to chlorpyriphos-methyl 0.4%, bendiocarb 0.1% and deltamethrin 0.05% were performed on natural populations of Ae. aegypti using the WHO protocol. The activity of enzymes involved in the rapid detoxification of insecticides, especially non-specific esterases, oxidases (cytochrome P450) and glutathione-S-transferases, was measured on individual mosquitos. The mortality rates for deltamethrin 0.05% were low and ranged from 20.72% to 89.62% in the Bobo-Dioulasso and Ouagadougou sites, respectively. When bendiocarb 0.1% was tested, the mortality rates ranged from 7.73% to 71.23%. Interestingly, in the two urban areas, mosquitoes were found to be fully susceptible to chlorpyriphos-methyl 0.4%. Elevated activity of non-specific esterases and glutathione-S-transferases was reported, suggesting multiple resistance mechanisms involved in Ae. aegypti populations from Bobo-Dioulasso and Ouagadougou (including cytochrome P450). This update to the insecticide resistance status within Ae. aegypti populations in the two biggest cities is important to better plan dengue vectors control in the country and provides valuable information for improving vector control strategies in Burkina Faso, West Africa. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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14 pages, 1791 KiB

Open AccessArticle

Spatiotemporal and Socioeconomic Risk Factors for Dengue at the Province Level in Vietnam, 2013–2015: Clustering Analysis and Regression Model

by Polly Ashmore, Johanna F. Lindahl, Felipe J. Colón-González, Vu Sinh Nam, Dang Quang Tan and Graham F. Medley

Trop. Med. Infect. Dis. 2020, 5(2), 81; https://doi.org/10.3390/tropicalmed5020081 - 19 May 2020

Cited by 11 | Viewed by 4334

Abstract

Dengue is a serious infectious disease threat in Vietnam, but its spatiotemporal and socioeconomic risk factors are not currently well understood at the province level across the country and on a multiannual scale. We explore spatial trends, clusters and outliers in dengue case [...] Read more.

Dengue is a serious infectious disease threat in Vietnam, but its spatiotemporal and socioeconomic risk factors are not currently well understood at the province level across the country and on a multiannual scale. We explore spatial trends, clusters and outliers in dengue case counts at the province level from 2011–2015 and use this to extract spatiotemporal variables for regression analysis of the association between dengue case counts and selected spatiotemporal and socioeconomic variables from 2013–2015. Dengue in Vietnam follows anticipated spatial trends, with a potential two-year cycle of high-high clusters in some southern provinces. Small but significant associations are observed between dengue case counts and mobility, population density, a province’s dengue rates the previous year, and average dengue rates two years previous in first and second order contiguous neighbours. Significant associations were not found between dengue case counts and housing pressure, access to electricity, clinician density, province-adjusted poverty rate, percentage of children below one vaccinated, or percentage of population in urban settings. These findings challenge assumptions about socioeconomic and spatiotemporal risk factors for dengue, and support national prevention targeting in Vietnam at the province level. They may also be of wider relevance for the study of other arboviruses, including Japanese encephalitis, Zika, and Chikungunya. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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11 pages, 1135 KiB

Open AccessArticle

Modelling the Use of Vaccine and Wolbachia on Dengue Transmission Dynamics

by Meksianis Z. Ndii

Trop. Med. Infect. Dis. 2020, 5(2), 78; https://doi.org/10.3390/tropicalmed5020078 - 13 May 2020

Cited by 18 | Viewed by 4270

Abstract

The use of vaccine and Wolbachia has been proposed as strategies against dengue. Research showed that the Wolbachia intervention is highly effective in areas with low to moderate transmission levels. On the other hand, the use of vaccine is strongly effective when it [...] Read more.

The use of vaccine and Wolbachia has been proposed as strategies against dengue. Research showed that the Wolbachia intervention is highly effective in areas with low to moderate transmission levels. On the other hand, the use of vaccine is strongly effective when it is implemented on seropositive individuals and areas with high transmission levels. The question that arises is could the combination of both strategies result in higher reduction in the number of dengue cases? This paper seeks to answer the aforementioned question by the use of a mathematical model. A deterministic model in the presence of vaccine and Wolbachia has been developed and analysed. Numerical simulations were presented and public health implications were discussed. The results showed that the performance of Wolbachia in reducing the number of dengue cases is better than that of vaccination if the vaccine efficacy is low, otherwise, the use of vaccine is sufficient to reduce dengue incidence and hence the combination of Wolbachia and vaccine is not necessary. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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9 pages, 1214 KiB

Open AccessArticle

Levels of 25-hydroxy Vitamin D3 and Vitamin D Receptor Polymorphism in Severe Dengue Cases from New Delhi

by Anita Chakravarti, Tanisha Bharara, Neeru Kapoor and Anzar Ashraf

Trop. Med. Infect. Dis. 2020, 5(2), 72; https://doi.org/10.3390/tropicalmed5020072 - 3 May 2020

Cited by 5 | Viewed by 3656

Abstract

Background: Dengue is the “phoenix” that never went to ashes. First identified in 1943, in Japan, dengue virus has worldwide distribution and is a grave public health concern in developing countries like India; Methods: A cross sectional study was conducted among adults suspected [...] Read more.

Background: Dengue is the “phoenix” that never went to ashes. First identified in 1943, in Japan, dengue virus has worldwide distribution and is a grave public health concern in developing countries like India; Methods: A cross sectional study was conducted among adults suspected of having dengue fever and attending Lok Nayak Hospital, New Delhi. Restriction Fragment Length Polymorphism was completed for the detection of vitamin D receptor (VDR) gene polymorphism; Results: Serum 25-hydroxy vitamin D3 (vitamin D) levels were found to be 1.6 times elevated in severe dengue cases as compared to healthy controls. Vitamin D levels were significantly higher in secondary infections compared to primary infections as well as secondary severe dengue cases as compared to secondary non-severe cases (p value < 0.05). A significant association of the T allele (rs2228570) was seen in severe dengue cases, while, when comparing the A/A with A/C and C/C genotypes (rs7975232) among dengue cases and healthy controls, the odds ratio was estimated to be 1.24 (0.55–2.75, p > 0.05) and 0.28 (0.08–0.96, p < 0.05) respectively; Conclusions: The present study is an attempt at decoding the role of vitamin D in dengue disease pathogenesis and exploring the role of genetic polymorphism in dengue disease pathogenesis. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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9 pages, 2059 KiB

Open AccessArticle

Land Use Changes and Cluster Identification of Dengue Hemorrhagic Fever Cases in Bandung, Indonesia

by Sri Yusnita Irda Sari, Yessika Adelwin and Fedri Ruluwedrata Rinawan

Trop. Med. Infect. Dis. 2020, 5(2), 70; https://doi.org/10.3390/tropicalmed5020070 - 2 May 2020

Cited by 6 | Viewed by 3562

Abstract

Dengue Hemorrhagic Fever (DHF) in Indonesia has increased steadily with Bandung as a hyper-endemic area holding a high number of cases for years. This study aimed to identify cluster areas and their correlation with land use changes which was indicated by changes of [...] Read more.

Dengue Hemorrhagic Fever (DHF) in Indonesia has increased steadily with Bandung as a hyper-endemic area holding a high number of cases for years. This study aimed to identify cluster areas and their correlation with land use changes which was indicated by changes of Normalized Difference Vegetation Index (NDVI). Hospital surveillance of 28,327 cases during 2008–2013 was geo-coded into sub-district levels and analyzed to find cluster areas over time and space using SaTScan and ArcGIS. Spearman correlation was used to analyze NDVI with Incidence Rate (IR) in each area. IR of DHF cases tended to increase over 6 years during high precipitation period. Cases were concentrated in several cluster areas in 2009 then moved to eastern part of the city in 2013. NDVI had negative correlation with IR in 2008 (r = −0.258; p = 0.001) and positive correlation in 2012 (r = 0.193; p = 0.017). Clear geographical pattern by cluster identification overtime is beneficial for targeting appropriate vector-control program. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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20 pages, 4878 KiB

Open AccessArticle

Dengue Fever and Severe Dengue in Barbados, 2008–2016

by Kirk Osmond Douglas, Sudip Kumar Dutta, Byron Martina, Fatih Anfasa, T. Alafia Samuels and Marquita Gittens-St. Hilaire

Trop. Med. Infect. Dis. 2020, 5(2), 68; https://doi.org/10.3390/tropicalmed5020068 - 2 May 2020

Cited by 7 | Viewed by 5590

Abstract

Analysis of the temporal, seasonal and demographic distribution of dengue virus (DENV) infections in Barbados was conducted using national surveillance data from a total of 3994 confirmed dengue cases. Diagnosis was confirmed either by DENV–specific real time reverse transcriptase polymerase chain reaction (rRT–PCR), [...] Read more.

Analysis of the temporal, seasonal and demographic distribution of dengue virus (DENV) infections in Barbados was conducted using national surveillance data from a total of 3994 confirmed dengue cases. Diagnosis was confirmed either by DENV–specific real time reverse transcriptase polymerase chain reaction (rRT–PCR), or non–structural protein 1 (NS1) antigen or enzyme linked immunosorbent assay (ELISA) tests; a case fatality rate of 0.4% (10/3994) was observed. The dengue fever (DF) prevalence varied from 27.5 to 453.9 cases per 100,000 population among febrile patients who sought medical attention annually. DF cases occurred throughout the year with low level of transmission observed during the dry season (December to June), then increased transmission during rainy season (July to November) peaking in October. Three major dengue epidemics occurred in Barbados during 2010, 2013 and possibly 2016 with an emerging three–year interval. DF prevalence among febrile patients who sought medical attention overall was highest among the 10–19 years old age group. The highest DF hospitalisation prevalence was observed in 2013. Multiple serotypes circulated during the study period and Dengue virus serotype 2 (DENV–2) was the most prevalent serotype during 2010, whilst DENV–1 was the most prevalent serotype in 2013. Two DENV–1 strains from the 2013 DENV epidemic were genetically more closely related to South East Asian strains, than Caribbean or South American strains, and represent the first ever sequencing of DENV strains in Barbados. However, the small sample size (n = 2) limits any meaningful conclusions. DF prevalence was not significantly different between females and males. Public health planning should consider DENV inter–epidemic periodicity, the current COVID–19 pandemic and similar clinical symptomology between DF and COVID–19. The implementation of routine sequencing of DENV strains to obtain critical data can aid in battling DENV epidemics in Barbados. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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12 pages, 2596 KiB

Open AccessArticle

Efficacy of Bacillus thuringiensis Treatment on Aedes Population Using Different Applications at High-Rise Buildings

by Zuhainy Ahmad Zaki, Nazri Che Dom and Ibrahim Ahmed Alhothily

Trop. Med. Infect. Dis. 2020, 5(2), 67; https://doi.org/10.3390/tropicalmed5020067 - 1 May 2020

Cited by 6 | Viewed by 3622

Abstract

Bacillus thuringiensis israelensis (Bti) is an effective biological insecticide for killing mosquito larvae. However, choosing the suitable application method for larviciding is critical in increasing its effectiveness. Therefore, this study aimed to determine the effectiveness of Bti (VectoBac^®) WG using various [...] Read more.

Bacillus thuringiensis israelensis (Bti) is an effective biological insecticide for killing mosquito larvae. However, choosing the suitable application method for larviciding is critical in increasing its effectiveness. Therefore, this study aimed to determine the effectiveness of Bti (VectoBac^®) WG using various applications at high-rise buildings. Three different applications of Bti treatment were applied at three high-rise buildings in Bandar Saujana Putra. The ULV machine is used for Pangsapuri Impian, a mist blower for Pangsapuri Seri Saujana and a pressured sprayer for BSP 21. BSP Skypark does not undergo treatment and acts as a control. The efficacy of Bti treatment was measured by analyzing the ovitrap surveillance data collected (POI and MLT) for pre and post-treatment. Post-treatment ovitrap surveillance indicates that the Aedes sp. mosquito density was lower than the density at the time of pre-treatment surveillance. Overall, the Aedes albopictus species in both an indoor and outdoor environment setting had shown a reduction. The highest Aedes sp. density reduction is seen through the use of mist blowers in outdoor settings for Aedes albopictus, (%POI reduction = 87.4%; %MLT reduction = 93.8%). The mist blower yielded results that is significantly higher compared to other larviciding applications; the order from greatest to the least was mist blower > pressured sprayer > ULV. It can be concluded that each application produces different degrees of effectiveness in reducing the Aedes sp. density in different environmental settings. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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12 pages, 1249 KiB

Open AccessArticle

A Mixed-Methods Approach to Understanding Knowledge of Mosquito-Borne Infections and Barriers for Protection in Hanoi, Vietnam

by Lorraine Chapot, Thang Nguyen-Tien, Long Pham-Thanh, Hung Nguyen-Viet, Luke Craven and Johanna F Lindahl

Trop. Med. Infect. Dis. 2020, 5(2), 66; https://doi.org/10.3390/tropicalmed5020066 - 1 May 2020

Cited by 6 | Viewed by 4894

Abstract

Dengue is a growing problem in Hanoi, with cyclical epidemics of increasing frequency and magnitude. In June 2019, we conducted a cross-sectional survey using mixed methods to investigate how inhabitants of Hanoi perceive and respond to the risk of mosquito-borne diseases (MBD). A [...] Read more.

Dengue is a growing problem in Hanoi, with cyclical epidemics of increasing frequency and magnitude. In June 2019, we conducted a cross-sectional survey using mixed methods to investigate how inhabitants of Hanoi perceive and respond to the risk of mosquito-borne diseases (MBD). A total of 117 participants recruited using a stratified random sampling method were interviewed in three districts of Hanoi. Knowledge and practices (KP) regarding MBDs were assessed using a pre-tested questionnaire. Inferential statistics were used to identify factors associated with KP scores and describe the relationship between variables. Additionally, a “risk-mapping” exercise was conducted in a subsample through semi-structured interviews and analyzed qualitatively and quantitatively using the System Effects platform. Factors significantly associated with knowledge scores were education and family history of MBDs. While knowledge and practice scores were found to be positively correlated in the statistical analysis, this was not corroborated by our observations on the field. The results also revealed gaps in knowledge about MBDs and vectors and highlighted a general feeling of powerlessness which prevented the adoption of protective behaviors. Therefore, educational interventions which provide concrete tools to empower communities should have a positive impact on improving vector control. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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Graphical abstract

9 pages, 1436 KiB

Open AccessArticle

The Removal of Subterranean Stormwater Drain Sumps as Mosquito Breeding Sites in Darwin, Australia

by Allan Warchot, Peter Whelan, John Brown, Tony Vincent, Jane Carter and Nina Kurucz

Trop. Med. Infect. Dis. 2020, 5(1), 9; https://doi.org/10.3390/tropicalmed5010009 - 10 Jan 2020

Cited by 5 | Viewed by 3008

Abstract

The Northern Territory Top End Health Service, Medical Entomology Section and the City of Darwin council carry out a joint Mosquito Engineering Program targeting the rectification of mosquito breeding sites in the City of Darwin, Northern Territory, Australia. In 2005, an investigation into [...] Read more.

The Northern Territory Top End Health Service, Medical Entomology Section and the City of Darwin council carry out a joint Mosquito Engineering Program targeting the rectification of mosquito breeding sites in the City of Darwin, Northern Territory, Australia. In 2005, an investigation into potential subterranean stormwater breeding sites in the City of Darwin commenced, specifically targeting roadside stormwater side entry pits. There were 79 side entry pits randomly investigated for mosquito breeding in the Darwin suburbs of Nightcliff and Rapid Creek, with 69.6% of the pits containing water holding sumps, and 45.6% of those water holding sumps breeding endemic mosquitoes. Culex quinquefasciatus was the most common mosquito collected, accounting for 73% of all mosquito identifications, with the potential vector mosquito Aedes notoscriptus also recovered from a small number of sumps. The sumps were also considered potential dry season maintenance breeding sites for important exotic Aedes mosquitoes such as Aedes aegypti and Aedes albopictus, which are potential vectors of dengue, chickungunya and Zika virus. Overall, 1229 side entry pits were inspected in ten Darwin suburbs from 2005 to 2008, with 180 water holding sumps identified and rectified by concrete filling. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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Review

Jump to: Research, Other

14 pages, 2883 KiB

Open AccessReview

Dengue Infections in Colombia: Epidemiological Trends of a Hyperendemic Country

by Hernando Gutierrez-Barbosa, Sandra Medina-Moreno, Juan C. Zapata and Joel V. Chua

Trop. Med. Infect. Dis. 2020, 5(4), 156; https://doi.org/10.3390/tropicalmed5040156 - 3 Oct 2020

Cited by 44 | Viewed by 7475

Abstract

Dengue is a major public health problem in hyperendemic countries like Colombia, the understanding of the epidemiological trends is important for the development of efficient public health policies. We conducted a systematic review of the epidemiologic data on dengue in Colombia from 1971 [...] Read more.

Dengue is a major public health problem in hyperendemic countries like Colombia, the understanding of the epidemiological trends is important for the development of efficient public health policies. We conducted a systematic review of the epidemiologic data on dengue in Colombia from 1971 to 2020. A total of 375 relevant citations were identified, 36 of which fulfilled the inclusion criteria. The data of dengue and severe dengue cases, infection fatality rate, and serotype distribution were used to understand and identify gaps in the epidemiological knowledge in Colombia. The epidemiology of dengue in this country was characterized by five main outbreaks in 1998, 2002, 2010, 2013, and 2019 with high fatality rates in comparison with the average values reported in the Americas. The case fatality rate of severe dengue exceeded 2% and all four serotypes co-circulate throughout the country with some regional variations. Overall, the behavior of dengue in Colombia is influenced by multiple factors including seasonal temperature variation and socioeconomic conditions. Additionally, the most important barriers in the epidemiological surveillance of dengue may be due to the insufficient notification rate in some regions and the low active search for the circulation of different serotypes. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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30 pages, 4150 KiB

Open AccessReview

Dengue and Zika Viruses: Epidemiological History, Potential Therapies, and Promising Vaccines

by Nelly M. Silva, Nuno C. Santos and Ivo C. Martins

Trop. Med. Infect. Dis. 2020, 5(4), 150; https://doi.org/10.3390/tropicalmed5040150 - 23 Sep 2020

Cited by 55 | Viewed by 14918

Abstract

Dengue virus (DENV), which can lead to fatal hemorrhagic fever, affects 390 million people worldwide. The closely related Zika virus (ZIKV) causes microcephaly in newborns and Guillain-Barré syndrome in adults. Both viruses are mostly transmitted by Aedes albopictus and Aedes aegypti mosquitoes, which, [...] Read more.

Dengue virus (DENV), which can lead to fatal hemorrhagic fever, affects 390 million people worldwide. The closely related Zika virus (ZIKV) causes microcephaly in newborns and Guillain-Barré syndrome in adults. Both viruses are mostly transmitted by Aedes albopictus and Aedes aegypti mosquitoes, which, due to globalization of trade and travel alongside climate change, are spreading worldwide, paving the way to DENV and ZIKV transmission and the occurrence of new epidemics. Local outbreaks have already occurred in temperate climates, even in Europe. As there are no specific treatments, these viruses are an international public health concern. Here, we analyze and discuss DENV and ZIKV outbreaks history, clinical and pathogenesis features, and modes of transmission, supplementing with information on advances on potential therapies and restraining measures. Taking advantage of the knowledge of the structure and biological function of the capsid (C) protein, a relatively conserved protein among flaviviruses, within a genus that includes DENV and ZIKV, we designed and patented a new drug lead, pep14-23 (WO2008/028939A1). It was demonstrated that it inhibits the interaction of DENV C protein with the host lipid system, a process essential for viral replication. Such an approach can be used to develop new therapies for related viruses, such as ZIKV. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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13 pages, 1842 KiB

Open AccessReview

High Seroprevalence of Dengue Virus Infection in Sudan: Systematic Review and Meta-Analysis

by Adel Hussein Elduma, A. Desiree LaBeaud, Jessica A. Plante, Kenneth S. Plante and Ayman Ahmed

Trop. Med. Infect. Dis. 2020, 5(3), 120; https://doi.org/10.3390/tropicalmed5030120 - 18 Jul 2020

Cited by 22 | Viewed by 4569

Abstract

The goal of this study was to systematically review the published data on dengue virus (DENV) seroprevalence in Sudan and to estimate disease burden through meta-analysis. We searched, reviewed, and extracted online available reports on DENV in Sudan. Among 168 identified records, 19 [...] Read more.

The goal of this study was to systematically review the published data on dengue virus (DENV) seroprevalence in Sudan and to estimate disease burden through meta-analysis. We searched, reviewed, and extracted online available reports on DENV in Sudan. Among 168 identified records, 19 were selected. Dengue infections were documented in 11/18 states. The overall seroprevalence of DENV in Sudan was estimated to be 27%, while the prevalence of dengue IgM was 22% and IgG was 38%. The prevalence of dengue estimated from community and hospital-based cross-sectional studies were 26% and 30% respectively. Additionally, one cohort study and a single PCR-based study reported a prevalence of 1% and 4%, respectively. Regional analysis revealed that the variation in seroprevalence in East, North, West, and Central Sudan was 23%, 24%, 36% and 43%, respectively. Interestingly, we found that DENV is circulating countrywide with a significant spatiotemporal variation in the disease seroprevalence. Furthermore, publications on dengue prevalence are temporally and geographically fragmented, perhaps due to limited resources. However, this gap in data and knowledge highlights the urgent need for a country-wide surveillance system and continued study of dengue burden in Sudan to accurately estimate the disease prevalence and determine the associated risk factors. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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Other

Jump to: Research, Review

12 pages, 832 KiB

Open AccessCase Report

A Cluster of Dengue Cases in Travelers: A Clinical Series from Thailand

by Hisham A. Imad, Juthamas Phadungsombat, Emi E. Nakayama, Lapakorn Chatapat, Phimphan Pisutsan, Wasin Matsee, Watcharapong Piyaphanee, Wang Nguitragool and Tatsuo Shioda

Trop. Med. Infect. Dis. 2021, 6(3), 152; https://doi.org/10.3390/tropicalmed6030152 - 14 Aug 2021

Cited by 3 | Viewed by 3922

Abstract

Dengue is an overlooked tropical disease for which billions of people are at risk. The disease, caused by a Flavivirus with four distinct serotypes, is transmitted primarily by urban Aedes mosquito species. The infection leads to a spectrum of clinical manifestations, with the [...] Read more.

Dengue is an overlooked tropical disease for which billions of people are at risk. The disease, caused by a Flavivirus with four distinct serotypes, is transmitted primarily by urban Aedes mosquito species. The infection leads to a spectrum of clinical manifestations, with the majority being asymptomatic. Primary dengue fever and, to a greater extent, a subsequent infection with a different serotype is associated with increased severity. Increased global travel and recreational tourism expose individuals naïve to the dengue viruses, the most common arboviral infections among travelers. We describe a cluster of possible primary acute dengue infections in a group of 12 individuals who presented to Bangkok Hospital for Tropical Diseases in 2017. Infection was confirmed by dengue NS1 antigen and multiplex real-time RT-PCR. Nine individuals required hospitalization, and four developed dengue warning signs. Leukocytes, neutrophils, and platelets declined towards defervescence and were negatively correlated with day of illness. Six clinical isolates were identified as dengue serotype-1, with 100% nucleotide identity suggesting that these patients were infected with the same virus. Full article

(This article belongs to the Special Issue Epidemiology of Dengue: Past, Present and Future (Volume II))

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