bims-mosdis 2022-07-03 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–07–03
nineteen papers selected by
Richard Halfpenny, Staffordshire University

A recent chikungunya outbreak associated with the occurrence of Aedes vectors (Diptera: Culicidae) in Kassala state, eastern Sudan in 2018.
Distribution Expansion of Dengue Vectors and Climate Change in India.
Mosquito (Diptera: Culicidae) Larval Ecology in Rubber Plantations and Rural Villages in Dabou (Côte d'Ivoire).
Acceptance of a Sterile Male Releases Pilot Project to Reduce Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) Populations and Its Associated Factors: A Community-based Cross-sectional Survey in South Chiapas, Mexico.
Reduced performance of community bednets against pyrethroid-resistant Anopheles funestus and Anopheles gambiae, major malaria vectors in Cameroon.
Assessing pyrethroid resistance status in the Culex pipiens complex (Diptera: Culicidae) from the northwest suburbs of Chicago, Illinois using Cox regression of bottle bioassays and other detection tools.
A closer look at the WHO cone bioassay: video analysis of the hidden effects of a human host on mosquito behaviour and insecticide contact.
Spatial patterns and climate drivers of malaria in three border areas of Brazil, Venezuela and Guyana, 2016-2018.
An ensemble forecast system for tracking dynamics of dengue outbreaks and its validation in China.
Population genetic structure and evolutionary genetics of Anopheles sinensis based on knockdown resistance (kdr) mutations and mtDNA-COII gene in China-Laos, Thailand-Laos, and Cambodia-Laos borders.
The effect of weather and climate on dengue outbreak risk in Peru, 2000-2018: A time-series analysis.
Visualization of scientific collaboration and themes for arbovirus disease in the caribbean: A forty-year trend analysis with focus on dengue, Zika and Chikungunya.
The Need for Strengthening Health Information Dissemination Toward Indoor Residual Spraying for Malaria Prevention in Malarious Area of Ethiopia.
One Health approach to improve the malaria elimination programme in Henan Province.
A malaria-free China: global importance and key experience.
Surveillance and response systems driving malaria elimination in the mountain areas of Hainan Province.
Two hidden taxa in the Japanese encephalitis vector mosquito, Culex tritaeniorhynchus, and the potential for long-distance migration from overseas to Japan.
DNA barcoding suggests new species for the Mansonia subgenus (Mansonia, Mansoniini, Culicidae, Diptera) in the area surrounding the Jirau hydroelectric dam, Porto Velho municipality, Rondônia state, Brazil.
Prevalence and force of Plasmodium vivax blood-stage infection and associated clinical malaria burden in the Brazilian Amazon.

Parasitol Int. 2022 Jun 22. pii: S1383-5769(22)00077-0. [Epub ahead of print]90 102613

A recent chikungunya outbreak associated with the occurrence of Aedes vectors (Diptera: Culicidae) in Kassala state, eastern Sudan in 2018.

Hanaa Adli Siam, Arwa Elaagip, Saif Alnaser Altag Abrahim, Mahmoud Hommed Mohammed, Omima Mahdi Noaman, Abdallah M Samy.

  Aedes aegypti and Ae. albopictus (Diptera: Culicidae) are primary vectors of human arboviral diseases such as dengue, chikungunya, yellow fever, and Zika viruses. Aedes aegypti is well distributed in Sudan, except in Northern and Khartoum states, while Ae. albopictus has not been previously reported. Recently, Eastern Sudan witnessed an unprecedented large outbreak of chikungunya fever between 31 May 2018 and 30 March 2019. The outbreak was composed of four waves; one of them was in Kassala state. Aedes survey in localities of Kassala state (rather than Kassala city) is carried out to assess the possible expansion of the disease in the state. The results showed the presence of immature stages of Aedes spp. in four localities from ten localities. From the four localities that recorded Aedes spp., two localities (Rural Kassala and West Kassala) were reported with chikungunya cases. From this investigation, Ae. albopictus was reported for the first time in Sudan. Also, this investigation showed the importance of conducting entomological surveys with epidemiological surveys during outbreaks of arboviral diseases.

Keywords:  Aedes aegypti; Aedes albopictus; Asian tiger mosquito; Chikungunya; Dengue; Kassala; Outbreak; Sudan

DOI:  https://doi.org/10.1016/j.parint.2022.102613
Geohealth. 2022 Jun;6(6): e2021GH000477

Distribution Expansion of Dengue Vectors and Climate Change in India.

Syed Shah Areeb Hussain, Ramesh C Dhiman.

  India has witnessed a five-fold increase in dengue incidence in the past decade. However, the nation-wide distribution of dengue vectors, and the impacts of climate change are not known. In this study, species distribution modeling was used to predict the baseline and future distribution of Aedine vectors in India on the basis of biologically relevant climatic indicators. Known occurrences of Aedes aegypti and Aedes albopictus were obtained from the Global Biodiversity Information Facility database and previous literature. Bio-climatic variables were used as the potential predictors of vector distribution. After eliminating collinear and low contributing predictors, the baseline and future prevalence of Aedes aegypti and Aedes albopictus was determined, under three Representative Concentration Pathway scenarios (RCP 2.6, RCP 4.5 and RCP 8.5), using the MaxEnt species distribution model. Aedes aegypti was found prevalent in most parts of the southern peninsula, the eastern coastline, north eastern states and the northern plains. In contrast, Aedes albopictus has localized distribution along the eastern and western coastlines, north eastern states and in the lower Himalayas. Under future scenarios of climate change, Aedes aegypti is projected to expand into unsuitable regions of the Thar desert, whereas Aedes albopictus is projected to expand to the upper and trans Himalaya regions of the north. Overall, the results provide a reliable assessment of vectors prevalence in most parts of the country that can be used to guide surveillance efforts, despite minor disagreements with dengue incidence in Rajasthan and the north east, possibly due to behavioral practices and sampling efforts.

Keywords:  Aedes aegypti; Aedes albopictus; climate change; dengue; species distribution

DOI:  https://doi.org/10.1029/2021GH000477
Ecohealth. 2022 Jun 27.

Mosquito (Diptera: Culicidae) Larval Ecology in Rubber Plantations and Rural Villages in Dabou (Côte d'Ivoire).

Issouf Traore, Zanakoungo Ibrahima Coulibaly, Kouadio Bernard Allali, Julie-Anne Akiko Tangena, Yao Lucien Konan, Ahoua Yapi, Mireille Dosso.

  In Côte d'Ivoire, rubber cultivation has more than doubled since 2010. These mass agricultural areas require a large workforce with little information on how this environment might impact risk of mosquito-borne diseases. The objective of this study was to assess the larval ecology of mosquitoes in rubber areas of Dabou, Côte d'Ivoire. From January to June 2017, an entomological survey was conducted of mature (MP) and immature (IP) rubber plantations, as well as in villages surrounded by rubber plantations (SV) and remote from rubber plantations (RV). The number and type of potential and positive breeding sites were recorded, and mosquito larval densities and diversity were estimated. Seven genera divided into 31 species including major vector such as Anopheles gambiae s.l. and Aedes aegypti were identified. A total of 1,660 waterbodies were identified with a larvae positivity rate of 63.1%. A majority of waterbodies were identified in SV (N = 875, 53.4% positivity rate), followed by MP (N = 422, 81.8% positivity rate), IP (N = 194, 72.2% positivity rate) and least in RV (N = 169, 57.4% positivity rate). The most important breeding sites for disease vectors were leaf axils in IP (N = 108, 77.1%), latex collection cups in MP (N = 332, 96.2%) and the containers abandoned in the SV (N = 242, 51.8%) as well as in the RV (N = 59, 60.8%). All these results allow us to affirm that the cultivation of rubber trees has an impact on the larval ecology by increasing the number of available sites and favoring a high larval density and diversity.

Keywords:  anthropogenic environmental change; emerging infectious diseases; malaria; mosquito larval ecology; rubber plantations; rural villages; waterbodies

DOI:  https://doi.org/10.1007/s10393-022-01594-8
Acta Trop. 2022 Jun 26. pii: S0001-706X(22)00265-0. [Epub ahead of print] 106573

Acceptance of a Sterile Male Releases Pilot Project to Reduce Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) Populations and Its Associated Factors: A Community-based Cross-sectional Survey in South Chiapas, Mexico.

Abel Jiménez-Alejo, Ana Laura Pacheco-Soriano, Pablo Liedo, Carlos F Marina, J Guillermo Bond, José Cruz Rodríguez-Ramos, Javier Valle, Ariane Dor.

  Worldwide, vector-transmitted diseases account for more than 17% of all infectious diseases and cause more than 700,000 deaths annually. The primary strategy to control the transmission of dengue, chikungunya and Zika focuses on the control of their vectors. Vector control programs depend mainly on the use of insecticides. However, these measures have failed to yield the desired results because the lack of proper control decreases their effectiveness over time. Also, the effect of insecticide use on non-target organisms, environmental contamination, and the development of insecticide resistance impose continuous challenges for insecticide-dependent control programs. The sterile insect technique, on the other hand, is a non-polluting and environment-friendly technique. The use of sterile insects is generally well established in agriculture, but human health interventions often require a consensus that combines social perceptions with scientific evidence. Factors associated with acceptance of the releases of sterile male Aedes aegypti mosquitoes were assessed with logistic regression models for two communities (Rio Florido and Hidalgo) in Tapachula, Chiapas, Mexico. The favourable opinion of the respondents about the project workers, and the fact that the releases of sterile mosquitoes would be managed by the Secretaría de Salud, were found to be factors that supported the acceptance of sterile mosquito releases. Factors associated with disapproval were community (Rio Florido and Hidalgo) and the misbelief that sterile male mosquitoes can bite. The differences observed between the communities included in this study might be the result of experiences with the releases, of social and community organisation, and of leadership by social actors.

Keywords:  95% CI, 95% confidence interval; CONACYT, Consejo Nacional de Ciencia y Tecnología; Cenaprece, Centro Nacional de Programas Preventivos y Control de Enfermedades; DCZ, dengue, chikungunya, and Zika; DSVII, Distrito de Salud VII de Tapachula, Chiapas; ECOSUR, El Colegio de la Frontera Sur; FAO, Food and Agriculture Organization of the United Nations; HG, Hidalgo; IAEA, International Atomic Energy Agency; INEGI, Instituto Nacional de Estadística y Geografía; OR, Odds ratio; PAHO, Pan American Health Organization; RF, Rio Florido; RP, Risk perception; RV, response variable; SIT, Sterile Insect Technique/Release of sterile male mosquitoes; SM, Sterile Mosquitoes; SSA, Secretaría de Salud/ Secretariat of Health; Sterile insect technique, vector-borne diseases, dengue, vector control, public acceptance AbbreviationsAe., Aedes; VBD, Vector-borne diseases; VIF, variance inflation factor; WHO, World Health Organization; aOR, adjusted odds ratio; df, degrees of freedom

DOI:  https://doi.org/10.1016/j.actatropica.2022.106573
Parasit Vectors. 2022 Jun 26. 15(1): 230

Reduced performance of community bednets against pyrethroid-resistant Anopheles funestus and Anopheles gambiae, major malaria vectors in Cameroon.

Emilie S Ngongang-Yipmo, Magellan Tchouakui, Benjamin D Menze, Leon M J Mugenzi, Flobert Njiokou, Charles S Wondji.

   BACKGROUND: Long-lasting insecticidal nets (LLINs) are a vital tool in the fight against malaria vectors. However, their efficacy in the field can be impacted by several factors, including patterns of usage, net age, mosquito resistance and the delayed mortality effect, all of which could influence malaria transmission. We have investigated the effectiveness of the various brands of LLINs available in markets and households in Cameroon on pyrethroid-resistant mosquitoes and assessed their post-exposure effect.
METHODS: Following quality control assessment on a susceptible laboratory mosquito strain, we evaluated the immediate and delayed mortality effects of exposure to LLINs (both newly bough LLINst and used ones collected from households in Elende village, Cameroon, in 2019) using standard WHO cone tests on Anopheles gambiae and Anopheles funestus populations collected from the Centre region of Cameroon. Alive female mosquitoes were genotyped for various resistance markers at different time points post-exposure to evaluate the impact of insecticide resistance on the efficacy of bednets.
RESULTS: The laboratory-susceptible strain experienced high mortality rates when exposed to all pyrethroid-only brands of purchased nets (Olyset® Net, Super Net, PermaNet® 2.0, Yorkool®, Royal Sentry®) (Mean±SEM: 68.66 ± 8.35% to 93.33 ± 2.90%). However, low mortality was observed among wild An. funestus mosquitoes exposed to the bednets (0 ± 0 to 28 ± 6.7%), indicating a reduced performance of these nets against field mosquitoes. Bednets collected from households also showed reduced efficacy on the laboratory strain (mortality: 19-66%), as well as displaying a significant loss of efficacy against the local wild strains (mortality: 0 ± 0% to 4 ± 2.6% for An. gambiae sensu lato and 0 ± 0% to 8 ± 3.2% for An. funestus). However, compared to the unexposed group, mosquitoes exposed to bednets showed a significantly reduced longevity, indicating that the efficacy of these nets was not completely lost. Mosquitoes with the CYP6P9a-RR and L119F-GSTe2 mutations conferring pyrethroid resistance showed greater longevity after exposure to the Olyset net than their susceptible counterparts, indicating the impact of resistance on bednet efficacy and delayed mortality.
CONCLUSION: These findings show that although standard bednets drastically lose their efficacy against pyrethroid-resistant field mosquitoes, they still are able to induce delayed mortality in exposed populations. The results of this study also provide evidence of the actual impact of resistance on the quality and efficacy of LLINs in use in the community, with mosquitoes carrying the CYP6P9a-RR and L119F-GSTe2 mutations conferring pyrethroid resistance living longer than their susceptible counterparts. These results highlight the need to use new-generation nets that do not rely solely on pyrethroids.

Keywords:  Anopheles funestus; Anopheles gambiae; CYP6P9a; GSTe2; Insecticide resistance; LLINs; Longevity; Malaria; Post-exposure

DOI:  https://doi.org/10.1186/s13071-022-05335-2
PLoS One. 2022 ;17(6): e0268205

Assessing pyrethroid resistance status in the Culex pipiens complex (Diptera: Culicidae) from the northwest suburbs of Chicago, Illinois using Cox regression of bottle bioassays and other detection tools.

Edwin R Burgess, Kristina Lopez, Patrick Irwin, Collin P Jaeger, Alden S Estep.

Culex pipiens complex is an important vector of epizootic and zoonotic pathogens, including West Nile virus. Chicago, Illinois and its suburbs have suffered high incidence of human West Nile virus infections in the past. This makes abatement programs in and around the Chicago area an essential service. The control of Cx. pipiens is often complicated by rapidly evolving resistance to pyrethroids, which are the most widely used chemical class in US mosquito abatement programs. The present study assessed Sumithrin® resistance in Cx. pipiens collected from five locations around Cook County, Illinois, neighboring the city limits of Chicago. According to CDC guidelines, samples from all five locations demonstrated some resistance to Sumithrin®. When assessed with Anvil®, a formulated product made of Sumithrin® synergized with piperonyl butoxide, susceptibility was rescued in mosquitoes from three out of the five locations, suggesting involvement of mixed-function oxidases and/or carboxylesterases in Sumithrin® resistance at these locations. Not all locations had susceptibility rescued by Anvil®, but these locations had relatively low knockdown resistance allele frequencies, suggesting that mechanisms other than knockdown resistance may be involved. Enzyme activities did not reveal any marked trends that could be related back to mortality in the bottle bioassays, which highlights the need for multiple types of assays to infer enzymatic involvement in resistance. Future directions in pyrethroid resistance management in Chicago area Cx. pipiens are discussed.

DOI: https://doi.org/10.1371/journal.pone.0268205
Malar J. 2022 Jul 01. 21(1): 208

A closer look at the WHO cone bioassay: video analysis of the hidden effects of a human host on mosquito behaviour and insecticide contact.

Angela Hughes, Agnes Matope, Mischa Emery, Keith Steen, Gregory Murray, Hilary Ranson, Philip J McCall, Geraldine M Foster.

   BACKGROUND: The WHO cone test is one of three tests currently used to evaluate the efficacy of insecticide-treated bed nets (ITNs). It generates two test outputs, knockdown and 24-h mortality, both indicative of immediate toxicity but that reveal little about the nature of mosquito and ITN interaction or how results translate to real-world settings.
METHODS: A human arm held 5 mm behind the net surface acted as a host attractant during cone tests and a smartphone was used to capture mosquito behaviour in the cone. Post-exposure blood feeding and survival for nine days were recorded; ingested blood meal size was determined by measuring excreted haematin. Four strains of Anopheles gambiae (insecticide susceptible: Kisumu and N'gousso; insecticide resistant: Banfora and VK7) were tested with and without the host attractant using untreated, Permanet 2.0 and Olyset nets. Video recordings were scan sampled every five seconds to record mosquito positions on either the net, in flight or in contact with the cone. Generalized estimating equations were used to analyse all data except survival within nine days which was analysed using Weighted Cox Regression.
RESULTS: Net contact was the most frequently recorded behaviour in all Anopheles spp. strains on all nets. Adding the human host as attractant triggered excitatory behaviours: in all strains, the magnitude of net contact was significantly decreased compared to tests without a host. ITN exposure altered the observed behaviour of the two susceptible strains, which exhibited a decreased response to the host during ITN tests. The resistant strains did not alter their behaviour during ITN tests. Significantly less net contact was observed during Olyset Net tests compared to Permanet 2.0. The host presence affected survival after exposure: Banfora and VK7 mosquitoes exposed to Permanet 2.0 with a host lived longer compared to tests performed without a host. However, mosquitoes that blood-fed and survived long enough to digest the blood meal did not exhibit significantly reduced longevity regardless of the presence of the host attractant.
CONCLUSIONS: Simple modifications to the WHO cone test and extension of post-test monitoring beyond the current 24 h enable detailed behavioural characterizations of individual ITNs to be compiled. The effects observed from testing with a host and including blood feeding suggest that more representative estimates of true of ITN efficacy are gained with these modifications than when using the current testing protocol.

Keywords:  Anopheles; Bednet; Behaviour; Bioassay; Control; ITN; Insecticide; Malaria; Mosquito; Pyrethroid; Vector

DOI:  https://doi.org/10.1186/s12936-022-04232-4
Sci Rep. 2022 Jun 29. 12(1): 10995

Spatial patterns and climate drivers of malaria in three border areas of Brazil, Venezuela and Guyana, 2016-2018.

Kinley Wangdi, Erica Wetzler, Horace Cox, Paola Marchesini, Leopoldo Villegas, Sara Canavati.

In 2020, 77% of malaria cases in the Americas were concentrated in Venezuela, Brazil, and Colombia. These countries are characterized by a heterogeneous malaria landscape and malaria hotspots. Furthermore, the political unrest in Venezuela has led to significant cross-border population movement. Hence, the aim of this study was to describe spatial patterns and identify significant climatic drivers of malaria transmission along the Venezuela-Brazil-Guyana border, focusing on Bolivar state, Venezuela and Roraima state, Brazil. Malaria case data, stratified by species from 2016 to 2018, were obtained from the Brazilian Malaria Epidemiology Surveillance Information System, the Guyana Vector Borne Diseases Program, the Venezuelan Ministry of Health, and civil society organizations. Spatial autocorrelation in malaria incidence was explored using Getis-Ord (Gi*) statistics. A Poisson regression model was developed with a conditional autoregressive prior structure and posterior parameters were estimated using the Bayesian Markov chain Monte Carlo simulation with Gibbs sampling. There were 685,498 malaria cases during the study period. Plasmodium vivax was the predominant species (71.7%, 490,861). Malaria hotspots were located in eight municipalities along the Venezuela and Guyana international borders with Brazil. Plasmodium falciparum increased by 2.6% (95% credible interval [CrI] 2.1%, 2.8%) for one meter increase in altitude, decreased by 1.6% (95% CrI 1.5%, 2.3%) and 0.9% (95% CrI 0.7%, 2.4%) per 1 cm increase in 6-month lagged precipitation and each 1 °C increase of minimum temperature without lag. Each 1 °C increase of 1-month lagged maximum temperature increased P. falciparum by 0.6% (95% CrI 0.4%, 1.9%). P. vivax cases increased by 1.5% (95% CrI 1.3%, 1.6%) for one meter increase in altitude and decreased by 1.1% (95% CrI 1.0%, 1.2%) and 7.3% (95% CrI 6.7%, 9.7%) for each 1 cm increase of precipitation lagged at 6-months and 1 °C increase in minimum temperature lagged at 6-months. Each 1°C increase of two-month lagged maximum temperature increased P. vivax by 1.5% (95% CrI 0.6%, 7.1%). There was no significant residual spatial clustering after accounting for climatic covariates. Malaria hotspots were located along the Venezuela and Guyana international border with Roraima state, Brazil. In addition to population movement, climatic variables were important drivers of malaria transmission in these areas.

DOI: https://doi.org/10.1038/s41598-022-14012-4
PLoS Comput Biol. 2022 Jun 27. 18(6): e1010218

An ensemble forecast system for tracking dynamics of dengue outbreaks and its validation in China.

Yuliang Chen, Tao Liu, Xiaolin Yu, Qinghui Zeng, Zixi Cai, Haisheng Wu, Qingying Zhang, Jianpeng Xiao, Wenjun Ma, Sen Pei, Pi Guo.

As a common vector-borne disease, dengue fever remains challenging to predict due to large variations in epidemic size across seasons driven by a number of factors including population susceptibility, mosquito density, meteorological conditions, geographical factors, and human mobility. An ensemble forecast system for dengue fever is first proposed that addresses the difficulty of predicting outbreaks with drastically different scales. The ensemble forecast system based on a susceptible-infected-recovered (SIR) type of compartmental model coupled with a data assimilation method called the ensemble adjusted Kalman filter (EAKF) is constructed to generate real-time forecasts of dengue fever spread dynamics. The model was informed by meteorological and mosquito density information to depict the transmission of dengue virus among human and mosquito populations, and generate predictions. To account for the dramatic variations of outbreak size in different seasons, the effective population size parameter that is sequentially updated to adjust the predicted outbreak scale is introduced into the model. Before optimizing the transmission model, we update the effective population size using the most recent observations and historical records so that the predicted outbreak size is dynamically adjusted. In the retrospective forecast of dengue outbreaks in Guangzhou, China during the 2011-2017 seasons, the proposed forecast model generates accurate projections of peak timing, peak intensity, and total incidence, outperforming a generalized additive model approach. The ensemble forecast system can be operated in real-time and inform control planning to reduce the burden of dengue fever.

DOI: https://doi.org/10.1371/journal.pcbi.1010218
Parasit Vectors. 2022 Jun 26. 15(1): 229

Population genetic structure and evolutionary genetics of Anopheles sinensis based on knockdown resistance (kdr) mutations and mtDNA-COII gene in China-Laos, Thailand-Laos, and Cambodia-Laos borders.

Yilong Zhang, Canglin Zhang, Linbo Wu, Chunhai Luo, Xiaofang Guo, Rui Yang, Yilong Zhang.

   BACKGROUND: Vector control is still a pivotal method for preventing malaria, and its potency is weakened by the increasing resistance of vectors to chemical insecticides. As the most abundant and vital malaria vector in Southeast Asia, the chemical insecticide resistance status in Anopheles sinensis remains elusive in Laos, which makes it imperative to evaluate the true nature of chemical insecticide resistance-associated genetic mutations in An. sinensis in Laos.
METHODS: Adult An. sinensis were collected from three border regions in Laos. DNA was extracted from individual mosquitoes. PCR amplification and DNA sequencing of a fragment containing codon 1014 of the voltage-gated sodium channel (vgsc) gene were completed to study the kdr allele frequency distribution, kdr intron polymorphism, population genetic diversity, and the evolutionary status of the kdr codon. The mitochondrial cytochrome c oxidase subunit II gene (COII) was amplified and sequenced to examine population variations, genetic differentiation, spatial population structure, population expansion, and gene flow patterns.
RESULTS: Nine wild kdr haplotypes of the vgsc gene were detected in this study, and eight of them, namely 1014L1, 1014L2, 1014L4, 1014L7, 1014L9, 1014L10, 1014L11, and 1014L21, were discovered in the China-Laos border (northern Laos), while 1014L3 was only detected in the Thailand-Laos border (northwestern Laos) and Cambodia-Laos border (southern Laos). The newly identified haplotype, 1014L21, was uniquely distributed in the China-Laos border and was not identified in other countries. Based on sequence analysis of the mitochondrial COII genes, significant genetic differentiation and limited gene flow were detected between the China-Laos and Cambodia-Laos An. sinensis populations, which suggested that those two regions were genetically isolated. The distinct distribution of the kdr haplotype frequencies is probably the result of geographical isolation in mosquito populations.
CONCLUSIONS: Lack of kdr mutations in the vgsc gene was probably due to genetic isolation and the absence of intense selection pressure in the three border regions of Laos. This study reveals that pyrethroid-based chemical insecticides are still appropriate for battling An. sinensis in parts of Laos, and routine monitoring of chemical insecticide resistance should be continuously implemented and focused on more restricted areas as part of chemical insecticide resistance management.

Keywords:  Anopheles sinensis; Evolution; Knockdown resistance; Mitochondrial DNA; Mutation; Voltage-gated sodium channel gene

DOI:  https://doi.org/10.1186/s13071-022-05366-9
PLoS Negl Trop Dis. 2022 Jun 30. 16(6): e0010479

The effect of weather and climate on dengue outbreak risk in Peru, 2000-2018: A time-series analysis.

Tia Dostal, Julianne Meisner, César Munayco, Patricia J García, César Cárcamo, Jose Enrique Pérez Lu, Cory Morin, Lauren Frisbie, Peter M Rabinowitz.

BACKGROUND: Dengue fever is the most common arboviral disease in humans, with an estimated 50-100 million annual infections worldwide. Dengue fever cases have increased substantially in the past four decades, driven largely by anthropogenic factors including climate change. More than half the population of Peru is at risk of dengue infection and due to its geography, Peru is also particularly sensitive to the effects of El Niño Southern Oscillation (ENSO). Determining the effect of ENSO on the risk for dengue outbreaks is of particular public health relevance and may also be applicable to other Aedes-vectored viruses.
METHODS: We conducted a time-series analysis at the level of the district-month, using surveillance data collected from January 2000 to September 2018 from all districts with a mean elevation suitable to survival of the mosquito vector (<2,500m), and ENSO and weather data from publicly-available datasets maintained by national and international agencies. We took a Bayesian hierarchical modeling approach to address correlation in space, and B-splines with four knots per year to address correlation in time. We furthermore conducted subgroup analyses by season and natural region.
RESULTS: We detected a positive and significant effect of temperature (°C, RR 1.14, 95% CI 1.13, 1.15, adjusted for precipitation) and ENSO (ICEN index: RR 1.17, 95% CI 1.15, 1.20; ONI index: RR 1.04, 95% CI 1.02, 1.07) on outbreak risk, but no evidence of a strong effect for precipitation after adjustment for temperature. Both natural region and season were found to be significant effect modifiers of the ENSO-dengue effect, with the effect of ENSO being stronger in the summer and the Selva Alta and Costa regions, compared with winter and Selva Baja and Sierra regions.
CONCLUSIONS: Our results provide strong evidence that temperature and ENSO have significant effects on dengue outbreaks in Peru, however these results interact with region and season, and are stronger for local ENSO impacts than remote ENSO impacts. These findings support optimization of a dengue early warning system based on local weather and climate monitoring, including where and when to deploy such a system and parameterization of ENSO events, and provide high-precision effect estimates for future climate and dengue modeling efforts.

DOI: https://doi.org/10.1371/journal.pntd.0010479
Travel Med Infect Dis. 2022 Jun 28. pii: S1477-8939(22)00142-9. [Epub ahead of print] 102396

Visualization of scientific collaboration and themes for arbovirus disease in the caribbean: A forty-year trend analysis with focus on dengue, Zika and Chikungunya.

Cédric Contaret, Raymond Césaire, Jacqueline Deloumeaux, Clarisse Joachim, André Cabié, Moustapha Dramé.

   BACKGROUND: The (re-)emergence of arboviruses in the Caribbean, and worldwide, is a major public health issue of concern to all scientific research stakeholders. This study aimed to use bibliometric analysis to identify the contribution of Caribbean countries to scientific production regarding the three arboviruses with the greatest impact, namely zika, chikungunya and dengue.
METHOD: Bibliographic data related to arbovirus diseases were collected from three international databases (Web of Science, Pubmed, and Scopus), filtered by Caribbean islands of affiliation. VosViewer was used to identify scientific connections between countries or institutions and to identify research themes.
RESULTS: The dataset comprised 1332 indexed articles, with 50% of articles categorized in the top quartile of quality. Cuba was found to lead research on dengue, with a total of 300 articles, and 18 international connections. The USA-Puerto Rico duo was found to be the leader on emerging arboviruses (Zika and Chikungunya), followed by a predominantly French-language cluster (mainland France, Guadeloupe, Martinique). Key research topics were related to clinical presentations, epidemiology, and research on mosquito-borne viruses CONCLUSIONS: Co-authorship network analysis on emerging arboviruses revealed the dynamics of collaboration, and provides insights into Caribbean collaborations that deserve to be created and consolidated in case of resurgence of new arbovirus epidemics.

Keywords:  Bibliometric; Caribbean; Chikungunya; Collaboration; Data visualization; Dengue; Zika

DOI:  https://doi.org/10.1016/j.tmaid.2022.102396
Front Public Health. 2022 ;10 913905

The Need for Strengthening Health Information Dissemination Toward Indoor Residual Spraying for Malaria Prevention in Malarious Area of Ethiopia.

Wubayehu Mekasha, Chala Daba, Asmamaw Malede, Sisay Abebe Debela, Mesfin Gebrehiwot.

   Introduction: Malaria remains prevalent in developing countries. This is particularly true among the community who are prone but do not apply malaria prevention and controlling strategies. In one of the malarious areas of Ethiopia (Shewa Robit), the acceptance level of indoor residual spraying (IRS) is indicated to be low as per guidelines. However, factors determining communities' acceptance of IRS are not well-investigated. Hence, this study was designed to identify the determinants for the acceptance of IRS in order to indicate priorities for malaria prevention and control.
Methods: A community-based cross-sectional study design was used among 649 households in Shewa Robit town, from February to March 2021. Households were selected from five IRS-targeted kebeles. Data were collected using structured questionnaire. A multivariable logistic regression model was used to identify the independent factors associated with the acceptance of IRS.
Results: The response rate in this study was 98%. The proportion of community who accepted the IRS for malaria prevention was 56.5% [95% confidence interval (CI): 52.7-60.2%]. Being male [adjusted odds ratio (AOR) = 2.21, 95% CI: 1.32-3.72], having good knowledge (AOR = 2.25, 95% CI: 1.33-3.84), did not paint/re-plaster the wall after spraying (AOR = 3.99, 95% CI: 2.36-6.76), did not perceive any side effects after spraying (AOR = 1.82, 95% CI: 1.11-2.99), effectiveness of previous IRS (AOR = 2.99, 95% CI: 1.85-4.84), non-utilization of long-lasting insecticide-treated net (LLIN) (AOR = 0.52, 95% CI: 0.33-0.84), and spraying the house at the right season (AOR: 2.14, 95% CI: 1.11-4.13) were determinant factors for the acceptance of IRS.
Conclusions: To increase the acceptance level of IRS among the communities, health interventions and services should focus on the awareness creation toward the effectiveness of IRS, proper spraying time/season, and side effects of IRS. Therefore, strengthening health information dissemination could help promote the acceptance of IRS.

Keywords:  Ethiopia; community acceptance level; health interventions; indoor residual spraying; malaria

DOI:  https://doi.org/10.3389/fpubh.2022.913905
Adv Parasitol. 2022 ;pii: S0065-308X(22)00003-3. [Epub ahead of print]116 153-186

One Health approach to improve the malaria elimination programme in Henan Province.

Ying Liu, Zhi-Quan He, Dan Wang, Ya-Bo Hu, Dan Qian, Cheng-Yun Yang, Rui-Min Zhou, Su-Hua Li, De-Ling Lu, Hong-Wei Zhang.

  One Health is a collaborative, multi-sectoral, trans-disciplinary approach with the goal of achieving optimal health outcomes by recognizing the interconnection between people, animals, plants, and the environment and determining how this relates to the control of infectious diseases such as malaria, schistosomiasis and so on. Malarias caused by Plasmodium that commonly infects female Anopheles mosquitoes, which feed on human blood and act as a disease vector. It has been a worldwide important public health problem from ancient times. Also, malaria is one of the infectious diseases with the longest epidemic time and the most serious harm in the history of Henan Province, China. During the past decades, the multi-sectoral, cross-regional, and multi-disciplinary One Health approach contributed to a significant reduction in malaria incidence, resulting in initiation of the Henan Malaria Elimination Action Plan. Herein, we reviewed the history of the fight against malaria in Henan Province. A full picture of malaria epidemics, prevention, and control strategies were showed, with the objective that it will help stakeholders, and policy-makers to take informed decisions on public health issues and intervention designs on malaria control towards elimination in the similar areas.

Keywords:  China; Control; Elimination; Henan; Malaria; One Health Approach

DOI:  https://doi.org/10.1016/bs.apar.2022.02.001
Adv Parasitol. 2022 ;pii: S0065-308X(22)00027-6. [Epub ahead of print]116 xv-xix

A malaria-free China: global importance and key experience.

Jian-Hai Yin, Christian Lengeler, Marcel Tanner, Xiao-Nong Zhou.

  Malaria has a worldwide distribution and is the world's deadliest mosquito-borne disease. The goal of malaria elimination is also reflected in the United Nations Sustainable Development Goals and the Global Technical Strategy for Malaria 2016-2030 issued by the World Health Organization (WHO). China succeeded in its malaria elimination programme after being certified as malaria-free by the WHO on 30 June 2021. Therefore, we document some of the key lessons learnt in the course of the malaria elimination effort in China in this special volume, showing how different strategies made elimination feasible in different subregions of China with different epidemiological and socioeconomic characteristics, in order to present strong signals to other malaria-endemic countries that malaria elimination is feasible within one generation.

Keywords:  China; Elimination; Lessons; Malaria; Strategy

DOI:  https://doi.org/10.1016/S0065-308X(22)00027-6
Adv Parasitol. 2022 ;pii: S0065-308X(22)00001-X. [Epub ahead of print]116 69-113

Surveillance and response systems driving malaria elimination in the mountain areas of Hainan Province.

Yuchun Li, Shanqing Wang, Ximin Hu, Yingjuan Huang, Renqiang Chen, Minchan Lin, Huanzhi Xu, Rongshen Ye, Datian Zhan, Shaoling Huang, Ji Zhen, Xiaodan Wen, Guoyi Wang, Yong Liu, Haishan Li, Zaichun Zheng, Jian Wang, Wen Zeng, Feng Meng, Xiaoming Huang, Guangze Wang, Bing Yang, Yan Chen.

  Hainan Province is in a tropical area of China and previously experienced serious P. falciparum and P. vivax malaria epidemics. After nearly 70 consecutive years of malaria prevention and control, malaria in Hainan has gradually been eliminated. To achieve the elimination of malaria, Hainan enacted six stages: investigative research and pilot prevention and control, large-scale antimalaria measures, adjustment of strategies for prevention and control, joint prevention and control measures, global funding of routine malaria control, and malaria elimination. Different strategies for malaria control were adopted at different stages. Malaria was most prevalent in the mountainous areas of central and southern Hainan, which contain a high-risk population (the forest goers) and two highly effective malaria vectors (An. dirus and An. minimus). Forest goers have been a high-risk population for malaria in Hainan since their identification in the 1990s. This paper summarizes malaria monitoring in forest goers and the response of forest goers to malaria control and elimination, distilling specific malaria control and elimination measures via case studies in Hainan Province. Two case studies in the malaria control stage demonstrated different measures for outbreaks and sporadic cases in forest goers. In view of the malaria outbreak in Sanya during the elimination stage, three-layered strategies (TLSs) were implemented to control outbreaks and improve control measures. Moreover, this paper also illustrates specific management measures to prevent malaria retransmission from sporadic imported malaria cases during the elimination phase. Hainan finally eliminated malaria in 2020. However, the risk of malaria retransmission is still high due to the prevalence of effective malaria vectors in Hainan, and forest goers are still a high-risk population for malaria retransmission.

Keywords:  Elimination; Hainan; Malaria; Response; Surveillance

DOI:  https://doi.org/10.1016/bs.apar.2022.01.001
PLoS Negl Trop Dis. 2022 Jun 30. 16(6): e0010543

Two hidden taxa in the Japanese encephalitis vector mosquito, Culex tritaeniorhynchus, and the potential for long-distance migration from overseas to Japan.

Satoru Arai, Ryusei Kuwata, Yukiko Higa, Yoshihide Maekawa, Yoshio Tsuda, Sudipta Roychoudhury, Arlene Garcia Bertuso, Tran Vu Phong, Nguyen Thi Yen, Tomoki Etoh, Akira Otuka, Masaya Matsumura, Takeshi Nabeshima, Keiko Tanaka Taya, Nobuhiko Okabe, Mutsuo Kobayashi, Kyoko Sawabe.

The Culex vishnui subgroups, particularly Culex tritaeniorhynchus, are considered the primary vectors of the Japanese encephalitis virus (JEV) in Asia. Recent molecular phylogenetic analyses of JEV isolates from Asian countries have shown that JEVs with diverse genetic variants are present in Asia. Furthermore, some JEV strains have been found to have crossed the East China Sea and been introduced into Japan. In this study, the possibility of overseas migration of the JE vector mosquito, Cx. tritaeniorhynchus was examined from the genetic, physical, and meteorological perspectives. Molecular phylogenetic analysis was performed based on both whole coding sequences and on the barcoding region of the mitochondrial cytochrome c oxidase subunit I (COI) gene of Cx. vishnui subgroups collected from Asian countries. Culex tritaeniorhymchus was classified into two genetically independent taxa by COI sequences: the Japanese type (Ct-J), which inhabits Japan except for the Amami Islands of southern Japan, and the continental type (Ct-C), which inhabits the Asian region except for Japan. It was confirmed that approximately 10% of Cx. tritaeniorhynchus trapped during the summer in western Kyushu were Ct-C, and that they could fly for up to 38 h continuously. The meteorological analysis also confirmed that the atmospheric flow occurring over the continent coincided with the date of Ct-C capture. This is the first report showing the existence of two taxa in Cx. tritaeniorhynchus. Their physical and physiological characteristics suggest the possibility of long-distance migration from overseas regions to Japan across the East China Sea. Future efforts are expected to provide evidence to support the occurrence of long-distance migration of Cx. tritaeniorhynchus with JEV.

DOI: https://doi.org/10.1371/journal.pntd.0010543
Acta Trop. 2022 Jun 26. pii: S0001-706X(22)00266-2. [Epub ahead of print] 106574

DNA barcoding suggests new species for the Mansonia subgenus (Mansonia, Mansoniini, Culicidae, Diptera) in the area surrounding the Jirau hydroelectric dam, Porto Velho municipality, Rondônia state, Brazil.

Vera Margarete Scarpassa, Elizângela Tavares Batista, Vânia da Costa Ferreira, Veríssimo Alvesdos Santos Neto, Rosemary Aparecida Roque, Francisco Augusto da Silva Ferreira, Fábio Medeiros da Costa.

  Previous studies have linked the construction of hydroelectric dams with increases in the density of mosquitoes, especially Mansonia. In Brazil, Mansonia mosquitoes are still poorly studied at the taxonomic, biological, ecological and epidemiological levels, and nothing is known about the genetic diversity and the cryptic speciation of the group. The current study analyzed the molecular taxonomy of Mansonia species captured in the area surrounding the Jirau hydroelectric dam, Rondônia state, Brazil. Samples were collected from fifteen locations between 2018 and 2019. Genomic DNA of the specimens was extracted, and the DNA barcode region of the Cytochrome Oxidase, subunit I gene was amplified with PCR and both DNA strands were sequenced. The dataset was analyzed using MEGA, Mr. Bayes and DnaSP software. The results provided COI sequences for 100 specimens collected in the area surrounding from Jirau hydroelectric dam. These belonged to five species of the Mansonia subgenus, identified morphologically as Mansonia humeralis, Mansonia amazonensis, Mansonia titillans, Mansonia dyari and Mansonia indubitans. Findings showed that the COI gene is an effective and accessible DNA barcode that provides a high-resolution tool for delimiting species within the subgenus Mansonia, with the tree construction (Bayesian Inference) well supported and non-overlapping intraspecific and interspecific (K2-P) genetic distance values. These findings also indicate the occurrence of cryptic speciation within M. dyari and near of M. titillans. This is the first study to apply molecular tools to the taxonomy of Mansonia species from Brazil.

Keywords:  Brazilian Amazon; Cryptic speciation; Hydroelectric dam; Mansonia; Taxonomy

DOI:  https://doi.org/10.1016/j.actatropica.2022.106574
Mem Inst Oswaldo Cruz. 2022 ;pii: S0074-02762022000101112. [Epub ahead of print]117 e210330

Prevalence and force of Plasmodium vivax blood-stage infection and associated clinical malaria burden in the Brazilian Amazon.

Wuelton Monteiro, Stephan Karl, Andrea Kuehn, Anne Almeida, Michael White, Sheila Vitor-Silva, Gisely Melo, Jose Diego Brito-Sousa, Djane Clarys Baia-da-Silva, Alexandre Vilhena Silva-Neto, Vanderson Sampaio, Quique Bassat, Ingrid Felger, Ivo Mueller, Marcus Lacerda.

BACKGROUND: Understanding the epidemiology of malaria through the molecular force of the blood-stage infection of Plasmodium vivax (molFOB) may provide a detailed assessment of malaria transmission.
OBJECTIVES: In this study, we investigated risk factors and spatial-temporal patterns of incidence of Plasmodium infection and clinical malaria episodes in three peri-urban communities of Manaus, Western Brazilian Amazon.
METHODS: Monthly samples were collected in a cohort of 1,274 individuals between April 2013 and March 2014. DNA samples were subject to Plasmodium species. molFOB was calculated by counting the number of genotypes observed on each visit, which had not been present in the preceding two visits and adjusting these counts by the respective times-at-risk.
FINDINGS: Respectively, 77.8% and 97.2% of the population remained free of P. vivax and P. falciparum infection. Expected heterozygosity for P. vivax was 0.69 for MSP1_F3 and 0.86 for MS2. Multiplicity of infection in P. vivax was close to the value of 1. The season was associated with P. vivax positivity [adjusted hazard ratio (aHR) 2.6 (1.9-5.7)] and clinical disease [aHR 10.6 (2.4-47.2)]. P. falciparum infection was associated with previous malarial episodes [HR 9.7 (4.5-20.9)]. Subjects who reported possession of a bed net [incidence rate ratio (IRR) 1.6 (1.2-2.2)] or previous malaria episodes [IRR 3.0 (2.0-4.5)] were found to have significantly higher P. vivax molFOB.
MAIN CONCLUSIONS: Overall, P. vivax infection prevailed in the area and infections were mostly observed as monoclonal. Previous malaria episodes were associated with significantly higher P. vivax molFOB.

DOI: https://doi.org/10.1590/0074-02760210330