bims-mosdis 2022-09-11 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–09–11
seventeen papers selected by
Richard Halfpenny, Staffordshire University

Development and evaluation of an efficient and real-time monitoring system for the vector mosquitoes, Aedes albopictus and Culex quinquefasciatus.
Evidence of High Frequencies of Insecticide Resistance Mutations in Aedes aegypti (Culicidae) Mosquitoes in Urban Accra, Ghana: Implications for Insecticide-based Vector Control of Aedes-borne Arboviral Diseases.
The mosquito vectors that sustained malaria transmission during the Magude project despite the combined deployment of indoor residual spraying, insecticide-treated nets and mass-drug administration.
Analysis of Aedes aegypti microRNAs in response to Wolbachia wAlbB infection and their potential role in mosquito longevity.
Overlap between dengue, Zika and chikungunya hotspots in the city of Rio de Janeiro.
Effect of delayed mating on reproductive performance and life-history parameters of dengue vector Aedes aegypti.
Little noticed, but very important: The role of breeding sites formed by bamboos in maintaining the diversity of mosquitoes (Diptera: Culicidae) in the Atlantic Forest biome.
Satellite observation to assess dengue risk due to Aedes aegypti and Aedes albopictus in a subtropical city of Argentina.
Sublethal exposure to spinetoram impacts life history traits and Dengue virus replication in Aedes aegypti.
Ecological variations in adult life table attributes of Aedes aegypti (L.) from the desert and coastal regions of India.
Rapid increase in neuroinvasive West Nile virus infections in humans, Italy, July 2022.
Sociocultural factors that influence the prevention of malaria in Ohangwena region, Namibia.
Occurrence of asymptomatic malaria infection and living conditions in the lowlands of Ethiopia: a community-based cross-sectional study.
Temporal trend and spatial clustering of the dengue fever prevalence in West Java, Indonesia.
Geographical clusters of dengue outbreak in Singapore during the Covid-19 nationwide lockdown of 2020.
Epidemiologic profile and histopathological findings in Neotropical Primates during and after the yellow fever outbreak in Espírito Santo, Brazil.
Epidemiology and clinical features of imported malaria: a 14-year retrospective single-centre descriptive study in Prague, Czech Republic.

PLoS Negl Trop Dis. 2022 Sep;16(9): e0010701

Development and evaluation of an efficient and real-time monitoring system for the vector mosquitoes, Aedes albopictus and Culex quinquefasciatus.

Zetian Lai, Jing Wu, Xiaolin Xiao, Lihua Xie, Tong Liu, Jingni Zhou, Ye Xu, Yiquan Cai, Feng Lin, Bin Li, Lu Gan, Anthony A James, Xiao-Guang Chen.

BACKGROUND: The surveillance of vector mosquitoes is essential for prevention and control of mosquito-borne diseases. In this study, we developed an internet-based vector mosquito monitor, MS-300, and evaluated its efficiency for the capture of the important vector mosquitoes, Aedes albopictus and Culex quinquefasciatus, in laboratory and field trials.
METHODOLOGY/PRINCIPAL FINDINGS: The linear sizes of adult Ae. albopictus and Cx. quinquefasciatus were measured and an infrared window was designed based on these data. A device to specifically attract these two species and automatically transmit the number of captured mosquitoes to the internet was developed. The efficiency of the device in capturing the two species was tested in laboratory, semi-field and open field trials. The efficiency results for MS-300 for catching and identifying Ae. albopictus in laboratory mosquito-net cages were 98.5% and 99.3%, and 95.8% and 98.6%, respectively, for Cx. quinquefasciatus. In a wire-gauze screened house in semi-field trials, the efficiencies of MS-300 baited with a lure in catching Ae. albopictus and Cx. quinquefasciatus were 54.2% and 51.3%, respectively, which were significantly higher than 4% and 4.2% without the lure. The real-time monitoring data revealed two daily activity peaks for Ae. albopictus (8:00-10:00 and 17:00-19:00), and one peak for Cx. quinquefasciatus (20:00-24:00). During a 98-day surveillance trial in the field, totals of 1,118 Ae. albopictus and 2,302 Cx. quinquefasciatus were captured by MS-300. There is a close correlation between the number of captured mosquitoes and the temperature in the field, and a positive correlation in the species composition of the captured samples among the mosquitoes using MS-300, BioGents Sentinel traps and human landing catches.
CONCLUSIONS/SIGNIFICANCE: The data support the conclusion that MS-300 can specifically and efficiently capture Ae. albopictus and Cx. quinquefasciatus, and monitor their density automatically in real-time. Therefore, MS-300 has potential for use as a surveillance tool for prevention and control of vector mosquitoes.

DOI: https://doi.org/10.1371/journal.pntd.0010701
J Med Entomol. 2022 Sep 06. pii: tjac120. [Epub ahead of print]

Evidence of High Frequencies of Insecticide Resistance Mutations in Aedes aegypti (Culicidae) Mosquitoes in Urban Accra, Ghana: Implications for Insecticide-based Vector Control of Aedes-borne Arboviral Diseases.

Godwin Kwame Amlalo, Jewelna Akorli, Nukunu Etornam Akyea-Bobi, Samuel Sowa Akporh, Dominic Aqua-Baidoo, Millicent Opoku, Kwadwo Frempong, Sellase Pi-Bansa, Helena A Boakye, Joannitta Joannides, Joseph Harold Nyarko Osei, Rebecca Pwalia, Esinam Abla Akorli, Alexander Manu, Samuel K Dadzie.

  The most widespread arboviral diseases such as Dengue, Chikungunya, and Zika are transmitted mainly by Aedes mosquitoes. Due to the lack of effective therapeutics for most of these diseases, vector control remains the most effective preventative and control measure. This study investigated and compared the species composition, insecticide susceptibility, and resistance mechanisms in Aedes mosquito populations from a forest reserve converted to an eco-park and a peri-domestic sites in urban Accra, Ghana. Immature Aedes were sampled from the study sites, raised to adults, and exposed to deltamethrin, permethrin, DDT, fenitrothion, bendiocarb, permethrin + PBO, and deltamethrin + PBO using WHO tube assays. Melting curve analyses were performed for F1536C, V1016I, and V410L genetic mutations in surviving and dead mosquitoes following exposure to deltamethrin and permethrin. Microplate assay was used to access enzyme activity levels in adult mosquitoes from both populations. Aedes aegypti was found to be the dominant species from both study populations. The susceptibility test results revealed a high frequency of resistance to all the insecticides except fenitrothion. F1534C mutations were observed in 100% and 97% of mosquitoes from the peri-domestic and forest population, respectively but were associated with pyrethroid resistance only in the forest population (P < 0.0001). For the first time in Aedes mosquitoes in Ghana, we report the existence V410L mutations, mostly under selection only in the forest population (HWE P < 0.0001) and conclude that Aedes vectors in urban Accra have developed resistance to many commonly used insecticides. This information is important for the formulation of vector control strategies for Aedes control in Ghana.

Keywords:   Aedes aegypti ; fenitrothion; insecticide resistance; piperonyl butoxide; pyrethroids

DOI:  https://doi.org/10.1093/jme/tjac120
PLoS One. 2022 ;17(9): e0271427

The mosquito vectors that sustained malaria transmission during the Magude project despite the combined deployment of indoor residual spraying, insecticide-treated nets and mass-drug administration.

Lucía Fernández Montoya, Helena Martí-Soler, Mara Máquina, Kiba Comiche, Inocencia Cuamba, Celso Alafo, Lizette L Koekemoer, Ellie Sherrard-Smith, Quique Bassat, Beatriz Galatas, Pedro Aide, Nelson Cuamba, Dulcisaria Jotamo, Francisco Saúte, Krijn P Paaijmans.

The "Magude project" aimed but failed to interrupt local malaria transmission in Magude district, southern Mozambique, by using a comprehensive package of interventions, including indoor residual spraying (IRS), pyrethroid-only long-lasting insecticide treated nets (LLINs) and mass-drug administration (MDA). Here we present detailed information on the vector species that sustained malaria transmission, their association with malaria incidence and behaviors, and their amenability to the implemented control interventions. Mosquitoes were collected monthly between May 2015 and October 2017 in six sentinel sites in Magude district, using CDC light traps both indoors and outdoors. Anopheles arabiensis was the main vector during the project, while An. funestus s.s., An. merus, An. parensis and An. squamosus likely played a secondary role. The latter two species have never previously been found positive for Plasmodium falciparum in southern Mozambique. The intervention package successfully reduced vector sporozoite rates in all species throughout the project. IRS was effective in controlling An. funestus s.s. and An. parensis, which virtually disappeared after its first implementation, but less effective at controlling An. arabiensis. Despite suboptimal use, LLINs likely provided significant protection against An. arabiensis and An. merus that sought their host largely indoors when people where in bed. Adding IRS on top of LLINs and MDA likely added value to the control of malaria vectors during the Magude project. Future malaria elimination attempts in the area could benefit from i) increasing the use of LLINs, ii) using longer-lasting IRS products to counteract the increase in vector densities observed towards the end of the high transmission season, and iii) a higher coverage with MDA to reduce the likelihood of human infection. However, additional interventions targeting vectors that survive IRS and LLINs by biting outdoors or indoors before people go to bed, will be likely needed to achieve local malaria elimination.

DOI: https://doi.org/10.1371/journal.pone.0271427
Sci Rep. 2022 Sep 09. 12(1): 15245

Analysis of Aedes aegypti microRNAs in response to Wolbachia wAlbB infection and their potential role in mosquito longevity.

Cameron Bishop, Mazhar Hussain, Leon E Hugo, Sassan Asgari.

The mosquito Aedes aegypti is the primary vector of a range of medically important viruses including dengue, Zika, West Nile, yellow fever, and chikungunya viruses. The endosymbiotic bacterium Wolbachia pipientis wAlbB strain is a promising biocontrol agent for blocking viral transmission by Ae. aegypti. To predict the long-term efficacy of field applications, a thorough understanding of the interactions between symbiont, host, and pathogen is required. Wolbachia influences host physiology in a variety of ways including reproduction, immunity, metabolism, and longevity. MicroRNAs (miRNAs) are highly conserved small non-coding RNAs that regulate gene expression in eukaryotes and viruses. Several miRNAs are known to regulate biological processes in Drosophila and mosquitoes, including facilitating Wolbachia maintenance. We generated the first chromosomal map of Ae. aegypti miRNAs, and compared miRNA expression profiles between a wAlbB-transinfected Ae. aegypti mosquito line and a tetracycline cleared derivative, using deep small RNA-sequencing. We found limited modulation of miRNAs in response to wAlbB infection. Several miRNAs were modulated in response to age, some of which showed greater upregulation in wAlbB-infected mosquitoes than in tetracycline cleared ones. By selectively inhibiting some differentially expressed miRNAs, we identified miR-2946-3p and miR-317-3p as effecting mosquito longevity in Wolbachia-infected mosquitoes.

DOI: https://doi.org/10.1038/s41598-022-19574-x
PLoS One. 2022 ;17(9): e0273980

Overlap between dengue, Zika and chikungunya hotspots in the city of Rio de Janeiro.

Eny Regina da Silva Queiroz, Roberto de Andrade Medronho.

BACKGROUND: Arboviruses represent a threat to global public health. In the Americas, the dengue fever is endemic. This situation worsens with the introduction of emerging, Zika fever and chikungunya fever, causing epidemics in several countries within the last decade. Hotspot analysis contributes to understanding the spatial and temporal dynamics in the context of co-circulation of these three arboviral diseases, which have the same vector: Aedes aegypti.
OBJECTIVE: To analyze the spatial distribution and agreement between the hotspots of the historical series of reported dengue cases from 2000 to 2014 and the Zika, chikungunya and dengue cases hotspots from 2015 to 2019 in the city of Rio de Janeiro.
METHODS: To identify hotspots, Gi* statistics were calculated for the annual incidence rates of reported cases of dengue, Zika, and chikungunya by neighborhood. Kendall's W statistic was used to analyze the agreement between diseases hotspots.
RESULTS: There was no agreement between the hotspots of the dengue fever historical series (2000-2014) and those of the emerging Zika fever and chikungunya fever (2015-2019). However, there was agreement between hotspots of the three arboviral diseases between 2015 and 2019.
CONCLUSION: The results of this study show the existence of persistent hotspots that need to be prioritized in public policies for the prevention and control of these diseases. The techniques used with data from epidemiological surveillance services can help in better understanding of the dynamics of these diseases wherever they circulate in the world.

DOI: https://doi.org/10.1371/journal.pone.0273980
Bull Entomol Res. 2022 Sep 06. 1-7

Effect of delayed mating on reproductive performance and life-history parameters of dengue vector Aedes aegypti.

R A K M Gunathilaka, D P W Jayatunga, G A S M Ganehiarachchi.

  Dengue is a fast-spreading mosquito-borne viral disease in the world. The primary vector of the disease is Aedes aegypti of the family Culicidae. It is a container breeder. Since a vaccine or a drug has not been developed against dengue, vector control appears to be the best method so far to control dengue. The current study was conducted to determine the effect of delayed mating on fecundity, fertility, life-history parameters, and longevity of Ae. aegypti, because such information can help formulate integrated vector control strategies involving the release of sub-fertile males into the environment. During this study, mating was delayed by 0, 2, 5, and 8 days after emergence. Males and females were separated by hand at the pupal stage using the apparent size difference of the sexes. The separated pupae were kept in separate cages until emergence. When mating was delayed for 8 days, the number of eggs laid by the female declined by 38%, and the percentage number of eggs that hatched reduced by 24%. However, the percentage of larval mortality, duration of the larval and pupal periods, and adult longevity were not significantly affected. The current results indicate that delayed mating has a negative effect on the reproductive performance of vector mosquitoes.

Keywords:  Aedes aegypti; delayed mating; reproductive performance

DOI:  https://doi.org/10.1017/S0007485322000396
PLoS One. 2022 ;17(9): e0273774

Little noticed, but very important: The role of breeding sites formed by bamboos in maintaining the diversity of mosquitoes (Diptera: Culicidae) in the Atlantic Forest biome.

Gerson Azulim Müller, Cecilia Ferreira de Mello, Anderson S Bueno, Wellington Thadeu de Alcantara Azevedo, Jeronimo Alencar.

This study investigated the composition of mosquito species in different kinds of breeding sites in a tropical forest remnant of the Atlantic Forest and identified species of public health concern therein. Collections of immature forms of mosquitoes were carried out monthly at the Poço das Antas Biological Reserve in southeastern Brazil, between June 2014 and June 2015. Samples were collected from four types of breeding sites: bamboos, bromeliads, puddles, and a lake. A total of 1,182 specimens of mosquitoes belonging to 28 species and 13 genera were collected. Three species, Ad. squamipennis, An. neglectus, and Wy. arthrostigma represented 64.8% of the captured specimens. Only three species were found in more than one type of breeding site: Ps. ferox, An. triannulatus, and Tx. trichopygus. Two species of public health concern were found breeding in bamboo (Ae. aegypti and Ae. albopictus) and one in the lake (An. darlingi). Bamboo had the highest species richness, Shannon diversity, abundance of individuals and number of dominant species of all breeding sites. Similar Simpson diversity was obtained for bamboo and bromeliads, with higher values than those obtained for puddles and the lake. The significance of the four breeding sites, especially bamboos, is discussed in the context of controlling populations of sylvatic species of mosquitoes in Atlantic Forest areas.

DOI: https://doi.org/10.1371/journal.pone.0273774
Med Vet Entomol. 2022 Sep 07.

Satellite observation to assess dengue risk due to Aedes aegypti and Aedes albopictus in a subtropical city of Argentina.

Mía Elisa Martín, Ana Carolina Alonso, Janinna Faraone, Marina Stein, Elizabet Lilia Estallo.

  Earth observation environmental features measured through remote sensing and models of vector mosquitoes species Aedes aegypti and Ae. albopictus provide an advancement with regards to dengue risk in urban environments of subtropical areas of Argentina. The authors aim to estimate the effect of landscape coverage and spectral indices (Normalized Difference Vegetation Index [NDVI], Normalized Difference Water Index [NDWI] and Normalized Difference Built-up Index [NDBI]) on the larvae abundance of Ae. aegypti and Ae. albopictus in Eldorado, Misiones, Argentina using remote satellite sensors. Larvae of these species were collected monthly (June 2016 to April 2018), in four environments: tire repair shops, cemeteries, dwellings and an urban natural park. The proportion of landscape coverage (water, urban areas, bare soil, low vegetation and high vegetation) was determined from the supervised classification of Sentinel-2 images and spectral indices, calculated. The authors developed spatial models of both vector species by generalized linear mixed models. The model's results showed that Ae. aegypti larvae abundance was better modelled by NDVI minimum values, NDBI maximum values and the interaction between them. For Ae. albopictus proportion of bare soil, low vegetation and the interaction between both variables explained better the abundance.

Keywords:  Aedes aegypti; Aedes albopictus; Eldorado city; dengue; landscape; public health; urban ecology; urban environment

DOI:  https://doi.org/10.1111/mve.12604
Insect Sci. 2022 Sep 07.

Sublethal exposure to spinetoram impacts life history traits and Dengue virus replication in Aedes aegypti.

Luoluo Wang, Zhichang Pang, Qi Chen, Zhentao Song, Yi Lu, Meng Yang, Jia Huang, Xiao-Qiang Yu, Xiaoyun Wang.

  Insecticides are anthropogenic environmental stressors and also a common stressor for mosquito vectors. However, the use of insecticides is often guided by short-term efficacy, and the sublethal effect on their target or non-target species has long been ignored. Here, we analyzed how sublethal exposure of the promising vector-control bioinsecticide spinetoram to Ae. aegypti larvae alter adult performance and susceptibility to dengue virus (DENV) infection. We found that the surviving adult mosquitoes were significantly smaller and exhibited weaker blood-feeding capacity than control females, apart from the extended immature development period. In terms of reproductive potential, although the F0 generation produced a similar number of eggs and offspring during the first gonotrophic cycle, the survival rates of the F1 generations were significantly lower as compared to the control group, suggesting the transgenerational sublethal effects on the F1 generation. Notably, the surviving adult females had higher DENV-2 viral loads than the control group after spinetoram sublethal exposure. Mechanistically, transcriptomic analysis showed that inhibition of oxidative phosphorylation (OXPHOS) may function in stimulating DENV production in adult Ae. aegypti. In Aag2 cells, the significant accumulation of apoptosis, mitochondrial ROS production and DENV-2 replication by spinetoram exposure consistently support our conclusion. Taken together, our study highlighted the threat of sublethal spinetoram exposure on the outbreaks of mosquito-borne viruses. This article is protected by copyright. All rights reserved.

Keywords:  Aedes aegypti; dengue virus; spinetoram; sublethal exposure; susceptibility

DOI:  https://doi.org/10.1111/1744-7917.13116
Med Vet Entomol. 2022 Sep 07.

Ecological variations in adult life table attributes of Aedes aegypti (L.) from the desert and coastal regions of India.

Gaurav Sharma, Souvik De, Udita Mandal, Rashmi Bhattacherjee, Devi Shankar Suman.

  The ecological variation in biological and adult life-table attributes of two populations of Aedes aegypti (Diptera: Culicidae) from the desert (Jodhpur) and coastal (Kolkata) regions of India are assessed to understand the reproductive and survival strategies. The results showed that females lived longer than males in both strains. The desert strain was more r-strategist because of its higher intrinsic rate of increase (rm = 0.23), finite rate of increase (λ = 1.25), lower life expectancy of males (7.9 days) and females (14.4 days), mean generation time (T = 19.2 days) and doubling time (DT = 3.0 days). However, there was no difference in net reproductive rate (R0 ) between the desert and coastal strains. The coastal strain showed a longer female life expectancy (22.0 days) than the desert strain (14.4 days). However, the fecundity (eggs/female/day) was lower in the coastal strain (11.4) than in the desert strain (15.1). Conclusively, the desert (Jodhpur) strain is adapted to a better r-strategy than the coastal (Kolkata) strain of Ae. aegypti, which might be helpful to flourish in harsh environmental conditions. This study may provide accurate predictions of Ae. aegypti population dynamics for vector management.

Keywords:  biological variation; ecology; mosquitoes; population dynamics; reproductive potential; survival

DOI:  https://doi.org/10.1111/mve.12609
Euro Surveill. 2022 Sep;27(36):

Rapid increase in neuroinvasive West Nile virus infections in humans, Italy, July 2022.

Italian Arbovirus Surveillance network

  As in 2018, when a large West Nile virus (WNV) epidemic occurred, the 2022 vector season in Italy was marked by an early onset of WNV circulation in mosquitoes and birds. Human infections were limited until early July, when we observed a rapid increase in the number of cases. We describe the epidemiology of human infections and animal and vector surveillance for WNV and compare the more consolidated data of June and July 2022 with the same period in 2018.

Keywords:  Italy; One Health; West Nile virus; epidemiology; outbreaks; public health policy; surveillance; vector-borne infections; viral infections

DOI:  https://doi.org/10.2807/1560-7917.ES.2022.27.36.2200653
Afr J Prim Health Care Fam Med. 2022 Aug 30. 14(1): e1-e10

Sociocultural factors that influence the prevention of malaria in Ohangwena region, Namibia.

Selma I Uushona, Jacob A Sheehama, Hermine Iita.

   BACKGROUND: Namibia is undergoing an epidemiological transition after decline in local transmission of malaria, and the country is now in a position to move towards eliminating local transmission by 2030. However, malaria prevalence cannot be adequately explained from medical and modern prevention points of view alone. The persistence of malaria might appear as a result of not recognising sociocultural factors that seem useful in the prevention of malaria, Hence, studies on sociocultural factors are limited.
AIM: The aim of this study was to describe the sociocultural factors that influence the prevention of malaria in Ohangwena region.
SETTING: The study was conducted in Ohangwena region of northern Namibia.
METHODS: This study was a cross-sectional study and a mixed methods, convergent parallel design was employed.
RESULTS: The major theme revealed that traditional prevention methods of malaria are widely available in rural communities. The best accepted traditional prevention methods include tumbleweed, bitter bush and animal dung. Quantitative findings indicated that 67.0% of participants felt that nets are expensive. Key barriers included the long distance to access health facilities (29.1%), long waiting times (25.8%) and the lack of money to pay for services and transport (22.5%).
CONCLUSION: The limited access to and cost of Western prevention methods minimise protection because of priority and resource allocations, but it could be mitigated with the use of locally available traditional prevention practices used for many years in curbing malaria. There is a need to create awareness about socioculturally congruent malaria care.Contribution: This study has revealed the need to combine standard prevention with traditional prevention practices in the fight against malaria, and it intensified research focusing on interventions that address sociocultural factors for the prevention of malaria in endemic regions. In addition, part of the novelty of the study is establishing the need to test the efficacy of traditional practices used.

Keywords:  Namibia.; Ohangwena region; malaria; prevention; sociocultural factors

DOI:  https://doi.org/10.4102/phcfm.v14i1.3524
Infect Dis Poverty. 2022 Sep 05. 11(1): 94

Occurrence of asymptomatic malaria infection and living conditions in the lowlands of Ethiopia: a community-based cross-sectional study.

Endale Mengesha Goshu, Meseret Dessalegne Zerefa, Habteyes Hailu Tola.

   BACKGROUND: A significant decline in malaria burden was documented in previously high burden African countries. Even though the global decline in malaria burden is significant, about 95% of it was typically found in 29 African countries and the decline was affected by COVID-19 in 2020. The considerable reduction in malaria incidence was noted due to effective prevention and treatment efforts, and rapid changes in living conditions. The relationship between the occurrence of asymptomatic malaria infection and household living conditions is well unstudied. This study aimed to determine the association between household living conditions and the occurrence of asymptomatic malaria in the lowlands of Ethiopia.
METHODS: A community-based cross-sectional study was conducted from January to March 2021 in twelve villages of Gambella, Southern Nation Nationalities and People Region and Afar in Ethiopia. A total of 1366 households were randomly selected, interviewed, and tested for malaria by rapid diagnostic test and blood film microscopic examination. Multiple logistic regression model was used to determine the independent association between living conditions and asymptomatic malaria infection.
RESULTS: The prevalence of asymptomatic malaria infection among individuals living in dwellings built with traditional floor/wall/roof ranges from 8.1% to 8.4% while it ranges from 2.0% to 4.6% among those living in modern floor/wall/roof houses. Dwellings built with traditional wall materials (P = 0.050), spending nights with cattle in the same house (P < 0.001), and availability of kitchen in the main house with no partition (P = 0.004) were significantly associated with asymptomatic malaria infection.
CONCLUSIONS: Asymptomatic malaria infection was 4.3 times higher among occupants residing in dwellings built with traditional wall materials; 5.6 times higher among households spending nights with cattle in the same house, and 2.3 times higher among households with kitchen in the main house with no partition. Therefore, policies and strategies on malaria elimination need to address or target improvements of the above listed living conditions for the community. A multi sectoral action is required to use these social determinants as a vector control strategic addition; and malaria elimination programs are expected to coordinate the implementation.

Keywords:  And livestock; Asymptomatic; Households; Malaria; Mosquito; Occurrence; Prevalence; Wall

DOI:  https://doi.org/10.1186/s40249-022-01018-3
Heliyon. 2022 Aug;8(8): e10350

Temporal trend and spatial clustering of the dengue fever prevalence in West Java, Indonesia.

Ilham Saiful Fauzi, Nuning Nuraini, Regina Wahyudyah Sonata Ayu, Bony Wiem Lestari.

  Dengue fever is a notable vector-borne viral disease, currently becoming the most dreaded worldwide health problem in terms of the number of people affected. A data set of confirmed dengue incidences collected in the province of West Java has allowed us to explore dengue's temporal trends and spatial distributions to obtain more obvious insights into its spatial-temporal evolution. We utilized the Richards model to estimate the growth rate and detect the peak (or turning point) of the dengue infection wave by identifying the temporal progression at each location. Using spatial analysis of geo-referenced data from a local perspective, we investigated the changes in the spatial clusters of dengue cases and detected hot spots and cold spots in each weekly cycle. We found that the trend of confirmed dengue incidences significantly increases from January to March. More than two-third (70.4%) of the regions in West Java had their dengue infection turning point ranging from the first week of January to the second week of March. This trend clearly coincides with the peak of precipitation level during the rainy season. Further, the spatial analysis identified the hot spots distributed across central, northern, northeastern, and southeastern regions in West Java. The densely populated areas were likewise seen to be associated with the high-risk areas of dengue exposure. Recognizing the peak of epidemic and geographical distribution of dengue cases might provide important insights that may help local authorities optimize their dengue prevention and intervention programs.

Keywords:  Dengue fever; Hot spot analysis; Infectious disease modeling; Richards model; Spatial clustering; Temporal trend

DOI:  https://doi.org/10.1016/j.heliyon.2022.e10350
Sci Data. 2022 Sep 07. 9(1): 547

Geographical clusters of dengue outbreak in Singapore during the Covid-19 nationwide lockdown of 2020.

Liping Huang, Gaoxi Xiao, Hechang Chen, Xuetong Niu, Xiuju Fu, Haiyan Xu, George Xu, Stefan Ma, Janet Ong, Lee Ching Ng.

Dengue, a mosquito-transmitted viral disease, has posed a public health challenge to Singaporean residents over the years. In 2020, Singapore experienced an unprecedented dengue outbreak. We collected a dataset of geographical dengue clusters reported by the National Environment Agency (NEA) from 15 February to 9 July in 2020, covering the nationwide lockdown associated with Covid-19 during the period from 7 April to 1 June. NEA regularly updates the dengue clusters during which an infected person may be tagged to one cluster based on the most probable infection location (residential apartment or workplace address), which is further matched to fine-grained spatial units with an average coverage of about 1.35 km2. Such dengue cluster dataset helps not only reveal the dengue transmission patterns, but also reflect the effects of lockdown on dengue spreading dynamics. The resulting data records are released in simple formats for easy access to facilitate studies on dengue epidemics.

DOI: https://doi.org/10.1038/s41597-022-01666-y
An Acad Bras Cienc. 2022 ;pii: S0001-37652022000701302. [Epub ahead of print]94(suppl 3): e20211229

Epidemiologic profile and histopathological findings in Neotropical Primates during and after the yellow fever outbreak in Espírito Santo, Brazil.

Andresa Guimarães, Mariana C Oliveira, Maria Cecilia M Kierulff, Olivia Mendonça-Furtado, Michelle N M Baptista, Sérgio L Mendes, Gilton Luiz Almada.

Yellow fever (YF) is a viral disease whose transmission involves non-human primates (NHP), mosquitoes, and humans. Between 2016 and 2018 occurred the largest YF outbreak in the last 100 years in Brazil. We analyzed epidemiologic profile and geographic distribution of epizootics and described most frequent histopathological findings in NHP that died during YF outbreak in the state of Espírito Santo. We consider 487 epizootics notifications registered at the State Health Department from January 2017 to July 2020. Throughout the state, 51 (65.4%) municipalities reported epizootics, with more cases in central and metropolitan areas. Reverse transcription polymerase chain reaction and immunohistochemistry were laboratory tests performed for diagnosis of yellow fever, with 160 (32.9%) positive results, 314 (64.5%) negative and 13 (2.7%) inconclusive. Histopathological findings were compared statistically between positive and negative animals for YF. The liver was the most affected organ. Hemorrhage, hepatocyte necrosis, steatosis, cholestasis and eosinophilic degeneration were statistically more frequent in positive animals. Tubular necrosis, nephritis, congestion and lymphoid hypoplasia on spleen were statistically correlated to positive animals. Knowledge of pathogenic aspect of YF is necessary to guarantee that samples from Neotropical primates are properly used for YF surveillance purposes, to ensure appropriate diagnoses and subsequent public health responses.

DOI: https://doi.org/10.1590/0001-3765202220211229
Malar J. 2022 Sep 06. 21(1): 257

Epidemiology and clinical features of imported malaria: a 14-year retrospective single-centre descriptive study in Prague, Czech Republic.

Milan Trojánek, Vyacheslav Grebenyuk, Lenka Richterová, Ivana Zicklerová, Eva Nohýnková, Zdenka Manďáková, Jakub Kantor, Hana Roháčová, František Stejskal.

   BACKGROUND: Malaria represents one of the most important imported tropical infectious diseases in European travellers. The objective of the study was to identify changes in the epidemiological features of imported malaria and to analyse the clinical findings and outcomes of imported malaria.
METHODS: This single-centre descriptive study retrospectively analysed the medical records of all imported malaria cases in travellers treated at the Department of Infectious Diseases of University Hospital Bulovka in Prague from 2006 to 2019.
RESULTS: The study included 203 patients with a median age of 37 years (IQR 30-48) and a male to female ratio of 3.72:1. Plasmodium falciparum was the predominant species (149/203), and its proportion significantly increased from 35/60 cases (58.3%) in 2006-2011 to 69/80 (86.3%) in 2016-2019 (p < 0.001). In contrast, the incidence of Plasmodium vivax malaria decreased from 19/60 cases (31.7%) in 2006-2011 to 5/80 (6.3%) in 2016-2019 (p < 0.001). Malaria was imported from sub-Saharan Africa in 161/203 cases (79.3%). The proportion of travellers from Southeast and South Asia decreased from 16/60 (26.7%) and 6/60 (10.0%) in 2006-2011 to 2/80 (2.5%) and no cases (0.0%) in 2016-2019, respectively (p < 0.001 and p = 0.006). Tourism was the most common reason for travel (82/203), however, the proportion of non-tourists significantly increased over time from 29/60 (48.3%) in 2006-2011 to 55/80 (68.8%) in 2016-2019, p = 0.015. Severe malaria developed in 32/203 (15.8%) patients who were significantly older (p = 0.013) and whose treatment was delayed (p < 0.001). Two lethal outcomes were observed during the study period.
CONCLUSIONS: This study demonstrated a significant increase in P. falciparum malaria, which frequently resulted in severe disease, especially in older patients and those with delayed treatment initiation. The rising proportion of imported malaria in non-tourists, including business travellers and those visiting friends and relatives, is another characteristic finding analogous to the trends observed in Western European and North American centres. The described changes in the aetiology and epidemiology of imported malaria may serve to optimize pre-travel consultation practices and improve post-travel diagnostics and medical care.

Keywords:  Antimalarials; Imported malaria; Malaria; Plasmodium; Travel medicine; Travelers

DOI:  https://doi.org/10.1186/s12936-022-04282-8