bims-mosdis 2022-05-29 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–05–29
23 papers selected by
Richard Halfpenny, Staffordshire University

Environmental factors influence the local establishment of Wolbachia in Aedes aegypti mosquitoes in two small communities in central Vietnam.
Interspecific mating bias may drive Aedes albopictus displacement of Aedes aegypti during its range expansion.
Dengue vectors in Africa: A review.
Trojan mosquitoes control dengue.
Transient Introgression of Wolbachia into Aedes aegypti Populations Does Not Elicit an Antibody Response to Wolbachia Surface Protein in Community Members.
Modeling the effect of rainfall changes to predict population dynamics of the Asian tiger mosquito Aedes albopictus under future climate conditions.
Wolbachia 16S rRNA haplotypes detected in wild Anopheles stephensi in eastern Ethiopia.
Temperature-Mediated Effects on Mayaro Virus Vector Competency of Florida Aedes aegypti Mosquito Vectors.
Vector Competence of Mediterranean Mosquitoes for Rift Valley Fever Virus: A Meta-Analysis.
Effectiveness of environmental interventions to reduce entomological indices of dengue, Zika, and chikungunya vector.
Assessing the distribution of invasive Asian mosquitoes in Northern Italy and modelling the potential spread of Aedes koreicus in Europe.
Malaria elimination on Hainan Island despite climate change.
Recommendations for environmental risk assessment of gene drive applications for malaria vector control.
Stimuli Followed by Avian Malaria Vectors in Host-Seeking Behaviour.
Juvenile hormone acts on male accessory gland function via regulating L -asparaginase expression and triacylglycerol mobilization in Aedes aegypti.
Uranotaenia (Pseudoficalbia) bhutanensis (Diptera: Culicidae), A New Species From Bhutan.
Citizen Science Mosquito Surveillance by Ad Hoc Observation Using the iNaturalist Platform.
Culex Flavivirus Isolation from Naturally Infected Mosquitoes Trapped at Rio de Janeiro City, Brazil.
Recurrent Plasmodium vivax Cases of Both Short and Long Latency Increased with Transmission Intensity and Were Distributed Year-Round in the Most Affected Municipalities of the RACCN, Nicaragua, 2013-2018.
Determinants of Malaria Morbidity Among School-Aged Children Living in East Hararghe Zone, Oromia, Ethiopia: A Community-Based Case-Control Study.
Retrospective Genomic Characterization of a 2017 Dengue Virus Outbreak, Burkina Faso.
Environmental Determinants of Malaria Prevalence and the Adaptation Strategies in Western Nepal.
Detection and Isolation of Sindbis Virus from Field Collected Mosquitoes in Timimoun, Algeria.

Gates Open Res. 2021 ;5 147

Environmental factors influence the local establishment of Wolbachia in Aedes aegypti mosquitoes in two small communities in central Vietnam.

Nguyen T Hien, Dang D Anh, Nguyen H Le, Nguyen T Yen, Tran V Phong, Vu S Nam, Tran N Duong, Nguyen B Nguyen, Duong T T Huong, Luu Q Hung, Chau N T Trinh, Nguyen V Hoang, Vien Q Mai, Le T Nghia, Nguyen T Dong, Le H Tho, Simon Kutcher, Tim P Hurst, Jacqui L Montgomery, Megan Woolfit, Edwige Rances, Le Nguyen, Jack Brown-Kenyon, Angela Caird, Breeanna J McLean, Inaki Iturbe-Ormaetxe, Scott A Ritchie, Scott L O'Neill, Peter A Ryan.

  Background: The wMel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown to reduce transmission of dengue and other pathogens, under both laboratory and field conditions. Here we describe the entomological outcomes of wMel Wolbachia mosquito releases in two small communities in Nha Trang City in central Vietnam. Methods: The wMel strain of Wolbachia was backcrossed into local Aedes aegypti genotype and mosquito releases were undertaken by community members or by staff. Field monitoring was undertaken to track Wolbachia establishment in local Ae. aegypti mosquito populations. Ecological studies were undertaken to assess relationships between environmental factors and the spatial and temporal variability in Wolbachia infection prevalence in mosquitoes. Results: Releases of wMel Wolbachia Ae. aegypti mosquitoes in two small communities in Nha Trang City resulted in the initial establishment of Wolbachia in the local Ae. aegypti mosquito populations, followed by seasonal fluctuations in Wolbachia prevalence. There was significant small-scale spatial heterogeneity in Wolbachia infection prevalence in the Tri Nguyen Village site, resulting in the loss of wMel Wolbachia infection in mosquitoes in north and center areas, despite Wolbachia prevalence remaining high in mosquitoes in the south area. In the second site, Vinh Luong Ward, Wolbachia has persisted at a high level in mosquitoes throughout this site despite similar seasonal fluctuations in wMel Wolbachia prevalence. Conclusion: Seasonal variation in Wolbachia infection prevalence in mosquitoes was associated with elevated temperature conditions, and was possibly due to imperfect maternal transmission of Wolbachia. Heterogeneity in Wolbachia infection prevalence was found throughout one site, and indicates additional factors may influence Wolbachia establishment.

Keywords:  Aedes aegypti; Dengue; Wolbachia; World Mosquito Program; mosquito release

DOI:  https://doi.org/10.12688/gatesopenres.13347.1
PNAS Nexus. 2022 May;1(2): pgac041

Interspecific mating bias may drive Aedes albopictus displacement of Aedes aegypti during its range expansion.

Jiayong Zhou, Shuang Liu, Hongkai Liu, Zhensheng Xie, Liping Liu, Lifeng Lin, Jinyong Jiang, Mingdong Yang, Guofa Zhou, Jinbao Gu, Xiaohong Zhou, Guiyun Yan, Anthony A James, Xiao-Guang Chen.

  Aedes albopictus is the most invasive mosquito in the world and often displaces Ae. aegypti in regions where their populations overlap. Interspecific mating has been proposed as a possible cause for this displacement, but whether this applies across the range of their sympatry remains unclear. Aedes albopictus and Ae. aegypti collected from allopatric and sympatric areas in China were allowed to interact in cage experiments with different crosses and sex-choices. The results confirm that asymmetric interspecific mating occurs in these populations with matings between allopatric Ae. albopictus males and Ae. aegypti females being significantly higher (55.2%) than those between Ae. aegypti males and Ae. albopictus females (27.0%), and sympatric mosquitoes showed a similar but lower frequency bias, 25.7% versus 6.2%, respectively. The cross-mated females can mate second time (remate) with the respective conspecific males and the 66.7% remating success of female Ae. albopictus was significantly higher than the 9.3% of Ae. aegypti females. Furthermore, 17.8% of the matings of Ae. albopictus males exposed to mixed pools of Ae. albopictus and Ae. aegypti females and 9.3% of the matings of Ae. aegypti males with mixed Ae. aegypti and Ae. albopictus females were interspecific. The difference in the length of clasper between male Ae. albopictus (0.524 mm) and Ae. aegypti (0.409 mm) may be correlated with corresponding mates. We conclude that stronger Ae. albopictus male interspecific mating and more avid female intraspecific remating result in a satyr effect and contribute to competitive displacement of Ae. aegypti as allopatric Ae. albopictus invade during range expansion.

Keywords:  Aedes aegypti; Aedes albopictus; interspecific mating; reproductive interference

DOI:  https://doi.org/10.1093/pnasnexus/pgac041
Heliyon. 2022 May;8(5): e09459

Dengue vectors in Africa: A review.

Diawo Diallo, Babacar Diouf, Alioune Gaye, El Hadji NDiaye, Ndeye Marie Sene, Ibrahima Dia, Mawlouth Diallo.

  Dengue fever is a mosquito-borne-disease of growing public health importance in Africa. The continuous increase of number and frequency of outbreaks of dengue fever, especially in urban area in Africa underline the need to review the current data available on vectors involved in dengue virus transmission in Africa. Here, we summarized the available data on vectors involved in the transmission of dengue virus in the sylvatic and urban environments, vertical transmission, vector competence studies, and vector control strategies used in Africa. The virus was isolated mainly from Aedes furcifer, Ae. luteocephalus, and Ae. taylori in the sylvatic environment and from Ae. aegypti and Ae. albopictus in the urban areas. Prospective and urgently needed studies on vectors biology, behavior, and alternative control strategies are suggested.

Keywords:  Africa; Dengue; Mosquito vectors; Sylvatic; Urban

DOI:  https://doi.org/10.1016/j.heliyon.2022.e09459
Commun Med (Lond). 2021 ;1 17

Trojan mosquitoes control dengue.

Andreia Cunha.

Dengue virus is transmitted by Aedes aegypti mosquitoes and causes the disease known as dengue. In a trial published in The New England Journal of Medicine, Utarini and colleagues report that release of wolbachia-infected A. aegypti populations in a dengue endemic area reduces the number of symptomatic cases and of hospitalisations.

DOI: https://doi.org/10.1038/s43856-021-00018-y
Pathogens. 2022 May 03. pii: 535. [Epub ahead of print]11(5):

Transient Introgression of Wolbachia into Aedes aegypti Populations Does Not Elicit an Antibody Response to Wolbachia Surface Protein in Community Members.

Elvina Lee, Tran Hien Nguyen, Thu Yen Nguyen, Sinh Nam Vu, Nhu Duong Tran, Le Trung Nghia, Quang Mai Vien, Thanh Dong Nguyen, Robson Kriiger Loterio, Iñaki Iturbe-Ormaetxe, Heather A Flores, Scott L O'Neill, Duc Anh Dang, Cameron P Simmons, Johanna E Fraser.

  Wolbachia is an endosymbiotic bacterium that can restrict the transmission of human pathogenic viruses by Aedes aegypti mosquitoes. Recent field trials have shown that dengue incidence is significantly reduced when Wolbachia is introgressed into the local Ae. aegypti population. Female Ae. aegypti are anautogenous and feed on human blood to produce viable eggs. Herein, we tested whether people who reside on Tri Nguyen Island (TNI), Vietnam developed antibodies to Wolbachia Surface Protein (WSP) following release of Wolbachia-infected Ae. aegypti, as a measure of exposure to Wolbachia. Paired blood samples were collected from 105 participants before and after mosquito releases and anti-WSP titres were measured by ELISA. We determined no change in anti-WSP titres after ~30 weeks of high levels of Wolbachia-Ae. aegypti on TNI. These data suggest that humans are not exposed to the major Wolbachia surface antigen, WSP, following introgression of Wolbachia-infected Ae. aegypti mosquitoes.

Keywords:  Aedes aegypti; Wolbachia; arbovirus; dengue virus; vector biology

DOI:  https://doi.org/10.3390/pathogens11050535
PLoS One. 2022 ;17(5): e0268211

Modeling the effect of rainfall changes to predict population dynamics of the Asian tiger mosquito Aedes albopictus under future climate conditions.

Shin Fukui, Yusuke Kuwano, Kazuki Ueno, Kazuyuki Atsumi, Shunji Ohta.

The population dynamics of mosquitoes in temperate regions are not as well understood as those in tropical and subtropical regions, despite concerns that vector-borne diseases may be prevalent in future climates. Aedes albopictus, a vector mosquito in temperate regions, undergoes egg diapause while overwintering. To assess the prevalence of mosquito-borne diseases in the future, this study aimed to simulate and predict mosquito population dynamics under estimated future climatic conditions. In this study, we tailored the physiology-based climate-driven mosquito population (PCMP) model for temperate mosquitoes to incorporate egg diapauses for overwintering. We also investigated how the incorporation of the effect of rainfall on larval carrying capacity (into a model) changes the population dynamics of this species under future climate conditions. The PCMP model was constructed to simulate mosquito population dynamics, and the parameters of egg diapause and rainfall effects were estimated for each model to fit the observed data in Tokyo. We applied the global climate model data to the PCMP model and observed an increase in the mosquito population under future climate conditions. By applying the PCMP models (with or without the rainfall effect on the carrying capacity of the A. albopictus), our projections indicated that mosquito population dynamics in the future could experience changes in the patterns of their active season and population abundance. According to our results, the peak population number simulated using the highest CO2 emission scenario, while incorporating the rainfall effect on the carrying capacity, was approximately 1.35 times larger than that predicted using the model that did not consider the rainfall effect. This implies that the inclusion of rainfall effects on mosquito population dynamics has a major impact on the risk assessments of mosquito-borne diseases in the future.

DOI: https://doi.org/10.1371/journal.pone.0268211
Parasit Vectors. 2022 May 24. 15(1): 178

Wolbachia 16S rRNA haplotypes detected in wild Anopheles stephensi in eastern Ethiopia.

Elizabeth Waymire, Sowmya Duddu, Solomon Yared, Dejene Getachew, Dereje Dengela, Sarah R Bordenstein, Meshesha Balkew, Sarah Zohdy, Seth R Irish, Tamar E Carter.

   BACKGROUND: About two out of three Ethiopians are at risk of malaria, a disease caused by the parasites Plasmodium falciparum and Plasmodium vivax. Anopheles stephensi, an invasive vector typically found in South Asia and the Middle East, was recently found to be distributed across eastern and central Ethiopia and is capable of transmitting both P. falciparum and P. vivax. The detection of this vector in the Horn of Africa (HOA) coupled with widespread insecticide resistance requires that new methods of vector control be investigated in order to control the spread of malaria. Wolbachia, a naturally occurring endosymbiotic bacterium of mosquitoes, has been identified as a potential vector control tool that can be explored for the control of malaria transmission. Wolbachia could be used to control the mosquito population through suppression or potentially decrease malaria transmission through population replacement. However, the presence of Wolbachia in wild An. stephensi in eastern Ethiopia is unknown. This study aimed to identify the presence and diversity of Wolbachia in An. stephensi across eastern Ethiopia.
METHODS: DNA was extracted from An. stephensi collected from eastern Ethiopia in 2018 and screened for Wolbachia using a 16S targeted PCR assay, as well as multilocus strain typing (MLST) PCR assays. Haplotype and phylogenetic analysis of the sequenced 16S amplicons were conducted to compare with Wolbachia from countries across Africa and Asia.
RESULTS: Twenty out of the 184 mosquitoes screened were positive for Wolbachia, with multiple haplotypes detected. In addition, phylogenetic analysis revealed two superclades, representing Wolbachia supergroups A and B (bootstrap values of 81 and 72, respectively) with no significant grouping of geographic location or species. A subclade with a bootstrap value of 89 separates the Ethiopian haplotype 2 from other sequences in that superclade.
CONCLUSIONS: These findings provide the first evidence of natural Wolbachia populations in wild An. stephensi in the HOA. They also identify the need for further research to confirm the endosymbiotic relationship between Wolbachia and An. stephensi and to investigate its utility for malaria control in the HOA.

Keywords:  Anopheles stephensi; Disease control; Horn of Africa; Malaria; Vector control; Wolbachia

DOI:  https://doi.org/10.1186/s13071-022-05293-9
Viruses. 2022 Apr 23. pii: 880. [Epub ahead of print]14(5):

Temperature-Mediated Effects on Mayaro Virus Vector Competency of Florida Aedes aegypti Mosquito Vectors.

Abdullah A Alomar, Barry W Alto.

  Mayaro virus (MAYV) is an emerging mosquito-borne arbovirus and public health concern. We evaluated the influence of temperature on Aedes aegypti responses to MAYV oral infection and transmission at two constant temperatures (20 °C and 30 °C). Infection of mosquito tissues (bodies and legs) and salivary secretions with MAYV was determined at 3, 9, 15, 21, and 27 days post ingestion. At both temperatures, we observed a trend of increase in progression of MAYV infection and replication kinetics over time, followed by a decline during later periods. Peaks of MAYV infection, titer, and dissemination from the midgut were detected at 15 and 21 days post ingestion at 30 °C and 20 °C, respectively. Mosquitoes were able to transmit MAYV as early as day 3 at 30 °C, but MAYV was not detectable in salivary secretions until day 15 at 20 °C. Low rates of MAYV in salivary secretions collected from infected mosquitoes provided evidence supporting the notion that a substantial salivary gland barrier(s) in Florida Ae. aegypti can limit the risk of MAYV transmission. Our results provide insights into the effects of temperature and time on the progression of infection and replication of MAYV in Ae. aegypti vectors.

Keywords:  Aedes aegypti; Mayaro; arbovirus; climate; per os infection

DOI:  https://doi.org/10.3390/v14050880
Pathogens. 2022 Apr 23. pii: 503. [Epub ahead of print]11(5):

Vector Competence of Mediterranean Mosquitoes for Rift Valley Fever Virus: A Meta-Analysis.

Alex Drouin, Véronique Chevalier, Benoit Durand, Thomas Balenghien.

  Rift Valley fever (RVF) is a zoonotic disease caused by a virus mainly transmitted by Aedes and Culex mosquitoes. Infection leads to high abortion rates and considerable mortality in domestic livestock. The combination of viral circulation in Egypt and Libya and the existence of unregulated live animal trade routes through endemic areas raise concerns that the virus may spread to other Mediterranean countries, where there are mosquitoes potentially competent for RVF virus (RVFV) transmission. The competence of vectors for a given pathogen can be assessed through laboratory experiments, but results may vary greatly with the study design. This research aims to quantify the competence of five major potential RVFV vectors in the Mediterranean Basin, namely Aedes detritus, Ae. caspius, Ae. vexans, Culex pipiens and Cx. theileri, through a systematic literature review and meta-analysis. We first computed the infection rate, the dissemination rate among infected mosquitoes, the overall dissemination rate, the transmission rate among mosquitoes with a disseminated infection and the overall transmission rate for these five mosquito species. We next assessed the influence of laboratory study designs on the variability of these five parameters. According to experimental results and our analysis, Aedes caspius may be the most competent vector among the five species considered.

Keywords:  Mediterranean Basin; Rift Valley fever virus; competence; meta-analysis; mosquito

DOI:  https://doi.org/10.3390/pathogens11050503
Acta Trop. 2022 May 19. pii: S0001-706X(22)00215-7. [Epub ahead of print] 106523

Effectiveness of environmental interventions to reduce entomological indices of dengue, Zika, and chikungunya vector.

Silvia Tortosa-La Osa, Eva Martín-Ruiz, Ángela Galán-Relaño, Antonio Olry de Labry-Lima.

  Vector-borne diseases are a major public health problem. Among them, dengue, Zika and chikungunya illnesses are increasing their incidence and geographical expansion. Since vector control is the main measure to prevent these diseases, this systematic review aims to determine the effectiveness of environmental interventions for the prevention of the transmission of these three diseases, as well as for the reduction of their burden. Experimental studies of environmental management interventions aimed at vector control were included. The outcome variables of interest were disease burden indicators and entomological indicators. Of the 923 references initially retrieved, after discarding those that were duplicated or didn't comply with the inclusion criteria, a total of 7 articles were included. All included studies carried out environmental manipulation interventions and only 1 carried out an environmental modification intervention. Regarding the outcome variables, all used entomological indicators (larval or pupae indices). Of those, pupae indices are better indicators of vector abundance. In 4 out of the 6 studies, there was a statistically significant reduction of the pupae indices related to the elimination of small containers, manipulation of large tanks and cleaning outdoor spaces. These interventions are easy to implement and involve little resources, which acquires special importance regarding areas with limited resources. Although it is assumed that a reduction of mosquitoes would lead to a reduction or the risk of transmission, a little evidence proving this has been published. It would be advisable that, in addition to entomological indicators, epidemiological, environmental and sociodemographic factors would be taken into consideration, bearing in mind that mosquito density is one of the many factors that influence the transmission of these viruses. None of the papers included used disease indicators, not allowing to demonstrate if environmental interventions contribute to reduce disease burden.

Keywords:  Dengue; Zika; arboviruses control; arboviruses prevention; chikungunya; environmental interventions; environmental management

DOI:  https://doi.org/10.1016/j.actatropica.2022.106523
Acta Trop. 2022 May 21. pii: S0001-706X(22)00228-5. [Epub ahead of print] 106536

Assessing the distribution of invasive Asian mosquitoes in Northern Italy and modelling the potential spread of Aedes koreicus in Europe.

Irene Arnoldi, Agata Negri, Laura Soresinetti, Mattia Brambilla, Davide Carraretto, Fabrizio Montarsi, Paolo Roberto, Andrea Mosca, Diego Rubolini, Claudio Bandi, Sara Epis, Paolo Gabrieli.

  In the last decade, Aedes koreicus and Aedes japonicus japonicus mosquitoes, which are competent vectors for various arboviruses of public health relevance, colonised Italy and other European countries. Nevertheless, information about their current and potential distribution is partial. Accordingly, in this study four regions of Northern Italy (Lombardy, Liguria, Piedmont and Aosta Valley) were surveyed during 2021 for the presence of eggs, larvae and pupae of these two invasive species. We found evidence for a widespread presence of Ae. koreicus in pre-Alpine territories of Lombardy and Piedmont. Larvae from the invasive subspecies of Ae. j. japonicus were also collected in the same geographic areas, though they were less frequent. Occurrence data from this study and results from previous monitoring campaigns were used to generate a Maxent model for the prediction of habitat suitability for Ae. koreicus mosquitoes in Northern Italy and the rest of Europe. Peri-urban areas located in proximity to forests, pastures and vineyards were revealed as highly suitable environments for colonisation by this invasive species. Maps of the potential distribution also suggest the presence of further suitable areas in currently uncolonized countries. We conclude that this invasive mosquito species has the potential for a broad expansion at the European level in the coming decades.

Keywords:  Europe; Northern Italy; anthropized areas; habitat suitability; invasive mosquito species; species distribution modelling

DOI:  https://doi.org/10.1016/j.actatropica.2022.106536
Commun Med (Lond). 2022 ;2 12

Malaria elimination on Hainan Island despite climate change.

Huaiyu Tian, Naizhe Li, Yapin Li, Moritz U G Kraemer, Hua Tan, Yonghong Liu, Yidan Li, Ben Wang, Peiyi Wu, Bernard Cazelles, José Lourenço, Dongqi Gao, Dingwei Sun, Wenjing Song, Yuchun Li, Oliver G Pybus, Guangze Wang, Christopher Dye.

   Background: Rigorous assessment of the effect of malaria control strategies on local malaria dynamics is a complex but vital step in informing future strategies to eliminate malaria. However, the interactions between climate forcing, mass drug administration, mosquito control and their effects on the incidence of malaria remain unclear.
Methods: Here, we analyze the effects of interventions on the transmission dynamics of malaria (Plasmodium vivax and Plasmodium falciparum) on Hainan Island, China, controlling for environmental factors. Mathematical models were fitted to epidemiological data, including confirmed cases and population-wide blood examinations, collected between 1995 and 2010, a period when malaria control interventions were rolled out with positive outcomes.
Results: Prior to the massive scale-up of interventions, malaria incidence shows both interannual variability and seasonality, as well as a strong correlation with climatic patterns linked to the El Nino Southern Oscillation. Based on our mechanistic model, we find that the reduction in malaria is likely due to the large scale rollout of insecticide-treated bed nets, which reduce the infections of P. vivax and P. falciparum malaria by 93.4% and 35.5%, respectively. Mass drug administration has a greater contribution in the control of P. falciparum (54.9%) than P. vivax (5.3%). In a comparison of interventions, indoor residual spraying makes a relatively minor contribution to malaria control (1.3%-9.6%).
Conclusions: Although malaria transmission on Hainan Island has been exacerbated by El Nino Southern Oscillation, control methods have eliminated both P. falciparum and P. vivax malaria from this part of China.

Keywords:  Diseases; Infectious diseases

DOI:  https://doi.org/10.1038/s43856-022-00073-z
Malar J. 2022 May 25. 21(1): 152

Recommendations for environmental risk assessment of gene drive applications for malaria vector control.

John B Connolly, John D Mumford, Debora C M Glandorf, Sarah Hartley, Owen T Lewis, Sam Weiss Evans, Geoff Turner, Camilla Beech, Naima Sykes, Mamadou B Coulibaly, Jörg Romeis, John L Teem, Willy Tonui, Brian Lovett, Aditi Mankad, Abraham Mnzava, Silke Fuchs, Talya D Hackett, Wayne G Landis, John M Marshall, Fred Aboagye-Antwi.

  Building on an exercise that identified potential harms from simulated investigational releases of a population suppression gene drive for malaria vector control, a series of online workshops identified nine recommendations to advance future environmental risk assessment of gene drive applications.

Keywords:  Ecological risk; Engagement; Environmental risk assessment; Gene drive; Malaria; Modelling; Population suppression; Vector control

DOI:  https://doi.org/10.1186/s12936-022-04183-w
Biology (Basel). 2022 May 09. pii: 726. [Epub ahead of print]11(5):

Stimuli Followed by Avian Malaria Vectors in Host-Seeking Behaviour.

Alfonso Marzal, Sergio Magallanes, Luz Garcia-Longoria.

  Vector-borne infectious diseases (e.g., malaria, dengue fever, and yellow fever) result from a parasite transmitted to humans and other animals by blood-feeding arthropods. They are major contributors to the global disease burden, as they account for nearly a fifth of all infectious diseases worldwide. The interaction between vectors and their hosts plays a key role driving vector-borne disease transmission. Therefore, identifying factors governing host selection by blood-feeding insects is essential to understand the transmission dynamics of vector-borne diseases. Here, we review published information on the physical and chemical stimuli (acoustic, visual, olfactory, moisture and thermal cues) used by mosquitoes and other haemosporidian vectors to detect their vertebrate hosts. We mainly focus on studies on avian malaria and related haemosporidian parasites since this animal model has historically provided important advances in our understanding on ecological and evolutionary process ruling vector-borne disease dynamics and transmission. We also present relevant studies analysing the capacity of feather and skin symbiotic bacteria in the production of volatile compounds with vector attractant properties. Furthermore, we review the role of uropygial secretions and symbiotic bacteria in bird-insect vector interactions. In addition, we present investigations examining the alterations induced by haemosporidian parasites on their arthropod vector and vertebrate host to enhance parasite transmission. Finally, we propose future lines of research for designing successful vector control strategies and for infectious disease management.

Keywords:  haemosporidian; mosquitoes; parasite manipulation hypothesis; preen oil; vector attractants

DOI:  https://doi.org/10.3390/biology11050726
Insect Sci. 2022 May 28.

Juvenile hormone acts on male accessory gland function via regulating L -asparaginase expression and triacylglycerol mobilization in Aedes aegypti.

Xiang-Yang Lyu, Xue-Li Wang, Dan-Qian Geng, Hong Jiang, Zhen Zou.

  Hormones control the reproductive development of Aedes aegypti mosquitoes. The adult male reproductive process and mating behavior require adequate nutrients and energy. Understanding the molecular mechanism linking hormone, energy metabolism, and reproduction in male mosquitoes is important. In this study, we found that the size of the male accessory gland (MAG), an essential part of the male reproductive system, was gradually increased after eclosion. However, it was significantly reduced in male mosquitoes deficient in methoprene-tolerant (Met), the receptor of juvenile hormone. Likewise, egg hatchability of females that mated with Met-depleted males showed the same downward trend. The mRNA level of the gene encoding accessory gland protein, L -asparaginase (ASNase), was reduced in Met dsRNA-treated males. Electrophoretic mobility shift assay and quantitative reverse-transcription PCR results revealed that Met was capable of binding directly to the promoter of ASNase and activated its transcription. RNA interference of ASNase in males resulted in the reduction of egg hatchability of the females that mated with them. These results showed that Met influenced the fecundity of male mosquitoes by directly upregulating the expression of the ASNase gene. Moreover, the levels of triacylglycerol and the sizes of lipid droplets were decreased by 72-78 h PE in the fat body cells, whereas both of them increased in Met-depleted male mosquitoes, indicating that Met knockdown reduced lipid catabolism. Therefore, these data demonstrate that Met might influence the egg hatchability of females by regulating lipid metabolism and the development of the MAG in male mosquitoes. This article is protected by copyright. All rights reserved.

Keywords:  Accessory gland protein; energy; juvenile hormone; lipid metabolism; male accessory gland; male mosquito

DOI:  https://doi.org/10.1111/1744-7917.13084
J Med Entomol. 2022 May 24. pii: tjac061. [Epub ahead of print]

Uranotaenia (Pseudoficalbia) bhutanensis (Diptera: Culicidae), A New Species From Bhutan.

Pradya Somboon, Rinzin Namgay, Ralph E Harbach.

  A new species of the subgenus Pseudoficalbia of the genus Uranotaenia is described from larvae found in a hole in a log at high altitude in montane forest in the Mongar District of Bhutan. Based on morphology, the larvae are sufficiently distinct from other species of the subgenus to be described and formally named here as Uranotaenia bhutanensis Somboon, Namgay & Harbach, n. sp. The species is a member of the Bimaculata Series. The chaetotaxy of the fourth-instar larva is provided.

Keywords:  larva; mosquito; taxonomy

DOI:  https://doi.org/10.1093/jme/tjac061
Int J Environ Res Public Health. 2022 May 23. pii: 6337. [Epub ahead of print]19(10):

Citizen Science Mosquito Surveillance by Ad Hoc Observation Using the iNaturalist Platform.

Larissa Braz Sousa, Stephen Fricker, Cameron E Webb, Katherine L Baldock, Craig R Williams.

  Citizen science mosquito surveillance has been growing in recent years due to both increasing concern about mosquito-borne disease and the increasing popularity of citizen science projects globally. Health authorities are recognising the potential importance of citizen science to expanding or enhancing traditional surveillance programs. Different programs have shown success in engaging communities to monitor species of medical importance through low-cost methods. The Mozzie Monitors project was established on iNaturalist-an open citizen science platform that allows participants to upload photos (i.e., observers) and assist identification (i.e., identifiers). This article describes the likelihood of citizen scientists submitting photos of mosquitoes, assesses user submission behaviour, and evaluates public health utility from these citizen science-derived data. From October 2018 to July 2021, the Mozzie Monitors project on iNaturalist received 2118 observations of 57 different species of mosquitoes across Australia. The number of observers in the system increased over time with more than 500 observers and 180 identifiers being active in the project since its establishment. Data showed species bias with large-bodied and colourful mosquitoes being over-represented. Analyses also indicate regional differentiation of mosquito fauna per state, seasonality of activity, and ecological information about mosquitoes. The iNaturalist citizen science platform also allows connectedness, facilitated communication and collaboration between overall users and expert entomologists, of value to medical entomology and mosquito management.

Keywords:  citizen science; mobile application; mosquito; public health

DOI:  https://doi.org/10.3390/ijerph19106337
Insects. 2022 May 19. pii: 477. [Epub ahead of print]13(5):

Culex Flavivirus Isolation from Naturally Infected Mosquitoes Trapped at Rio de Janeiro City, Brazil.

Cinthya Amaral, Daniel Câmara, Tiago Salles, Marcelo Damião Meneses, Carlla de Araújo-Silva, Vanessa Dias, Fábio da Costa, Lúcio Caldas, Renata Azevedo.

  Culex Flavivirus (CxFV) is a classical insect-specific virus, which has aroused interest after the first indication that it can produce in nature superinfection exclusion of viruses of medical interest such as West Nile. Despite the detection of CxFV in different regions, CxFV ecology and the influence of co-circulation of arboviruses remains poorly understood. Therefore, our primary goals are to observe the occurrence of CxFV infection in mosquitoes trapped in an urban area of Rio de Janeiro, Brazil, characterize the virus circulating, and provide isolates. A prospective study was carried out for eight months on the campus of the Federal University of Rio de Janeiro, trapping adult mosquitoes. The CxFV minimum infection rates were determined in this period, and the virus isolation process is fully described. Samples from this study were grouped into genotype 2, along with CxFV sequences from Latin America and Africa.

Keywords:  Culex Flavivirus; Culex species; flavivirus; insect-specific virus; virus isolation

DOI:  https://doi.org/10.3390/insects13050477
Int J Environ Res Public Health. 2022 May 19. pii: 6195. [Epub ahead of print]19(10):

Recurrent Plasmodium vivax Cases of Both Short and Long Latency Increased with Transmission Intensity and Were Distributed Year-Round in the Most Affected Municipalities of the RACCN, Nicaragua, 2013-2018.

Aida M Soto, Lilia González-Cerón, Frida Santillán-Valenzuela, María E Parrales, Alberto Montoya.

  The characteristics of P. vivax recurrent episodes were examined using a centralized secondary source of malaria records in Nicaragua and in the two most affected municipalities in the RACCN. The study of 36,787 malaria cases due to P. vivax or P. falciparum revealed that, nationwide, 3624 patients had at least one recurrent infection. This was achieved by matching names, gender, age, community/municipality, ethnicity, etc. P. vivax was responsible for 88% of recurrent infections of 25-450 days of latency (51.9% were women and 48.1% were men), and these were assumed to be relapse episodes. Of them, 88.2% and 4.4% occurred in the municipalities of Puerto Cabezas and Rosita, respectively. The proportion of P. vivax patients having presumed relapse episodes rose with elevated transmission rates in both municipalities, reaching 7% in Rosita (2017) and 14.5% in Puerto Cabezas (2018). In both areas, relapse episodes were evident over time and were characterized by the production of a continuous stippling pattern with a slope evolving from one transmission peak to the next. During the dry season, short-latency relapse episodes were more robust, while long-latency ones increased just before the P. vivax transmission season began, with a high proportion of long-latency relapses during this period. The abundance of recurrent P. vivax infections, the wide range of relapse latency lengths, and temporal distribution tended to favor year-round transmission. It is necessary to evaluate compliance with and the effectiveness of primaquine treatment and contemplate the use of an alternative drug, among other actions.

Keywords:  Nicaragua; Plasmodium vivax; latency; malaria cases; recurrent cases; relapse; secondary case report; transmission intensity

DOI:  https://doi.org/10.3390/ijerph19106195
Pediatric Health Med Ther. 2022 ;13 183-193

Determinants of Malaria Morbidity Among School-Aged Children Living in East Hararghe Zone, Oromia, Ethiopia: A Community-Based Case-Control Study.

Mohammedawel Abdishu, Tesfaye Gobena, Melake Damena, Hassen Abdi, Abdi Birhanu.

   Background: Understanding the determinants of malaria morbidity offers helpful insights toward the changing malaria situation, which might lead to the adjustment of malaria program activities. Even though the determinants of malaria morbidity remain unknown, school-aged children were the highest malaria morbidity contributors in the East Hararghe Zone. Therefore, this study aimed to assess the determinants of malaria morbidity among school-aged children in the study area from February 1 to May 31, 2020.
Methods: A case-control study was conducted among school-aged children living in ten randomly selected low, moderate, and high malaria transmission kebeles. Cases were confirmed as positive for malaria, while controls were confirmed as negative for malaria among randomly selected school-aged children. Rapid diagnostic testing (RDT) and blood film (BF) malaria testing methods were used. Multivariable logistic regression was used to identify association between malaria and its determinants.
Results: The determinants of malaria infection were having no formal education (adjusted odds ratio (AOR)=4.91, 95% CI: 1.20-20.17), low family wealth index (AOR=2.50, 95% CI: 1.22-5.12), being from rural residence (AOR=2.34, 95% CI: 1.87-4.12), living near to stagnant water (AOR=2.01, 95% CI: 1.14-3.54), having a maximum of three family members (AOR=0.37, 95% CI: 0.18-0.78), using indoor residual spraying (IRS) (AOR=0.15, 95% CI: 0.08-0.29) and long-lasting insecticide-treated net (LLITN) over the last night (AOR=0.19, 95% CI: 0.10-0.35), and living in the house surrounded by cultivated land(AOR=0.24, 95%CI: 0.10-0.60) compared with their counterparts.
Conclusion: This study revealed that residence, family size, education, wealth index, stagnant water existence, and using LLITN and IRS had significant association with malaria morbidity. Thus, all concerned bodies, including the community should strengthen working on stagnant water elimination around their house to cut the breeding site of the malaria vector mosquito. Moreover, the findings have an important implication for improving interventions targeting the economic status and literacy of the society that may help in the reduction of the risk of malaria in the school-aged children.

Keywords:  Ethiopia; determinants; malaria; school-aged children

DOI:  https://doi.org/10.2147/PHMT.S347621
Emerg Infect Dis. 2022 Jun;28(6): 1198-1210

Retrospective Genomic Characterization of a 2017 Dengue Virus Outbreak, Burkina Faso.

Andrew G Letizia, Catherine B Pratt, Michael R Wiley, Anne T Fox, Mba Mosore, Bright Agbodzi, Clara Yeboah, Selassie Kumordjie, Nicholas Di Paola, Kone Cisse Assana, David Coulidiaty, Casimir Ouedraogo, Joseph H Kofi Bonney, William Ampofo, Zékiba Tarnagda, Lassana Sangaré.

  Knowledge of contemporary genetic composition of dengue virus (DENV) in Africa is lacking. By using next-generation sequencing of samples from the 2017 DENV outbreak in Burkina Faso, we isolated 29 DENV genomes (5 serotype 1, 16 serotype 2 [DENV-2], and 8 serotype 3). Phylogenetic analysis demonstrated the endemic nature of DENV-2 in Burkina Faso. We noted discordant diagnostic results, probably related to genetic divergence between these genomes and the Trioplex PCR. Forward and reverse1 primers had a single mismatch when mapped to the DENV-2 genomes, probably explaining the insensitivity of the molecular test. Although we observed considerable homogeneity between the Dengvaxia and TetraVax-DV-TV003 vaccine strains as well as B cell epitopes compared with these genomes, we noted unique divergence. Continual surveillance of dengue virus in Africa is needed to clarify the ongoing novel evolutionary dynamics of circulating virus populations and support the development of effective diagnostic, therapeutic, and preventive countermeasures.

Keywords:  Africa; Burkina Faso; RT-PCR; dengue virus; diagnostics; mosquito-borne diseases; next-generation sequencing; outbreak; phylogenetics; vector-borne infections; viruses

DOI:  https://doi.org/10.3201/eid2806.212491
J Nepal Health Res Counc. 2022 Mar 13. 19(4): 754-761

Environmental Determinants of Malaria Prevalence and the Adaptation Strategies in Western Nepal.

Uttam Paudel, Krishna Prasad Pant, Shiva Raj Adhikari, Sashi Silwal, Bimala Baral, Laxmi Ghimire, Sabitri Devi Adhikari, Sudip Paudel, Anil Poudyal, Meghnath Dhimal.

   BACKGROUND: Current literatures seem devoted only on relating climate change with malaria. Overarching all possible environmental determinants of malaria prevalence addressed by scanty literature in Nepal is found apposite research at this moment. This study aims to explore the environmental determinants of malaria prevalence in western Nepal.
METHODS: Cross-sectional data collected from community people were used to identify the environmental determinants of malaria prevalence in western Nepal. Probit and logistic regressions are used for identifying determinants.
RESULTS: The results reveal that environmental variables: winter temperature (aOR: 2.14 [95% CI: 1.00-4.56]), flooding (aOR: 2.45 [CI: 1.28-4.69]), heat waves (aOR: 3.14 [CI: 1.16-8.46]) and decreasing river water level (aOR: 0.25 [CI: 0.13-0.47]) are found major factors to influence malaria prevalence in western Nepal. Besides, pipeline drinking water (aOR: 0.37 [0.17-0.81]), transportation facility (aOR: 1.18 [1.07-1.32]) and awareness programs (aOR: 2.62 [0.03-6.65]) are exigent social issues to influence malaria prevalence in Nepal. To be protected from disease induced by environmental problems, households have used extra season specific clothes, iron nets and mosquito nets, use of insecticide in cleaning toilet and so on.
CONCLUSIONS: Adaptation mechanism against these environmental issues together with promoting pipeline drinking water, transportation facility and awareness programs are the important in malaria control in Nepal. Government initiation with incentivized adaptation mechanism for the protection of environment with caring household attributes possibly help control malaria in western Nepal.

Keywords:  Adaptation strategy; environmental changes; malaria; probit/logistic model; Nepal.

DOI:  https://doi.org/10.33314/jnhrc.v19i04.2967
Viruses. 2022 Apr 25. pii: 894. [Epub ahead of print]14(5):

Detection and Isolation of Sindbis Virus from Field Collected Mosquitoes in Timimoun, Algeria.

Nazli Ayhan, Aissam Hachid, Laurence Thirion, Kamel Eddine Benallal, Laura Pezzi, Fayez Ahmed Khardine, Chahrazed Benbetka, Sihem Benbetka, Zoubir Harrat, Remi Charrel.

  Sindbis virus (SINV) is a zoonotic alphavirus (family Togaviridae, genus Alphavirus) that causes human diseases in Africa, Europe, Asia, and Australia. Occasionally, SINV outbreaks were reported in South Africa and northern Europe. Birds are the main amplifying hosts of SINV, while mosquitoes play the role of the primary vector. Culex mosquitoes were collected in Algeria and subsequently tested for SINV. SINV RNA was detected in 10 pools out of 40, from a total of 922 mosquitoes tested. A strain of SINV was isolated from a pool displaying high viral load. Whole-genome sequencing and phylogenetic analysis showed that the SINV Algeria isolate was most closely related to a Kenyan strain. This was the first record of SINV in Algeria and more broadly in northwestern Africa, which can be a potential risk for human health in the circulating area. Further studies are needed to measure the impact on public health through seroprevalence studies in Algeria.

Keywords:  Algeria; Culex perexiguus; Culex pipiens; Sindbis virus; Togaviridae; alphavirus; arbovirus

DOI:  https://doi.org/10.3390/v14050894