bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2023–01–29
ten papers selected by
Richard Halfpenny, Staffordshire University
  1. Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Oviposition Activity and the Associated Socio-environmental Factors in the New Orleans Area.
  2. Entomopathogenic nematodes isolated from agricultural areas of Thailand and their activity against the larvae of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae).
  3. Impact of randomised wmel Wolbachia deployments on notified dengue cases and insecticide fogging for dengue control in Yogyakarta City.
  4. Seasonal changes in the diversity, host preferences and infectivity of mosquitoes in two arbovirus-endemic regions of Costa Rica.
  5. A comparative analysis of Aedes albopictus and Aedes aegypti subjected to diapause-inducing conditions reveals conserved and divergent aspects associated with diapause, as well as novel genes associated with its onset.
  6. Efficacy of pyriproxyfen-pyrethroid long-lasting insecticidal nets (LLINs) and chlorfenapyr-pyrethroid LLINs compared with pyrethroid-only LLINs for malaria control in Benin: a cluster-randomised, superiority trial.
  7. Getting ahead of insecticide-resistant malaria vector mosquitoes.
  8. "A comparative analysis of risk factors of malaria" case study Gisagara and Bugesera District of Rwanda. RDHS 2014/2015. A retrospective study.
  9. Prediction of the Risk Distributions for Anopheles sinensis, a Vector for Malaria in Shanghai, China.
  10. Dengue, chikungunya and Zika virus infections among Dutch travellers to Suriname: a prospective study during the introduction of chikungunya and Zika virus, 2014 to 2017.
  1. J Med Entomol. 2023 Jan 23. pii: tjad007. [Epub ahead of print]
    Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Oviposition Activity and the Associated Socio-environmental Factors in the New Orleans Area.
    Panpim Thongsripong, Brendan H Carter, Matthew J Ward, Samuel B Jameson, Sarah R Michaels, Joshua O Yukich, Dawn M Wesson.
      The transmission of Aedes-borne viruses is on the rise globally. Their mosquito vectors, Aedes aegypti (Linnaeus, Diptera: Culicidae) and Ae. albopictus (Skuse, Diptera: Culicidae), are focally abundant in the Southern United States. Mosquito surveillance is an important component of a mosquito control program. However, there is a lack of long-term surveillance data and an incomplete understanding of the factors influencing vector populations in the Southern United States. Our surveillance program monitored Ae. aegypti and Ae. albopictus oviposition intensity in the New Orleans area using ovicups in a total of 75 sites from 2009 to 2016. We found both Aedes spp. throughout the study period and sites. The average number of Ae. aegypti and Ae. albopictus hatched from collected eggs per site per week was 34.1 (SD = 57.7) and 29.0 (SD = 46.5), respectively. Based on current literature, we formed multiple hypotheses on how environmental variables influence Aedes oviposition intensity, and constructed Generalized Linear Mixed Effect models with a negative binomial distribution and an autocorrelation structure to test these hypotheses. We found significant associations between housing unit density and Ae. aegypti and Ae. albopictus oviposition intensity, and between median household income and Ae. albopictus oviposition intensity. Temperature, relative humidity, and accumulated rainfall had either a lagged or an immediate significant association with oviposition. This study provides the first long-term record of Aedes spp. distribution in the New Orleans area, and sheds light on factors associated with their oviposition activity. This information is vital for the control of potential Aedes-borne virus transmission in this area.
    Keywords:   Aedes aegypti ; Aedes albopictus ; Generalized Linear Mixed Effect Model; oviposition trap; socio-environmental factors
    DOI:  https://doi.org/10.1093/jme/tjad007
  2. Acta Trop. 2023 Jan 23. pii: S0001-706X(23)00029-3. [Epub ahead of print]240 106842
    Entomopathogenic nematodes isolated from agricultural areas of Thailand and their activity against the larvae of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae).
    Jiranun Ardpairin, Chanakan Subkrasae, Abdulhakam Dumidae, Pichamon Janthu, Wipanee Meesil, Paramaporn Muangpat, Sarunporn Tandhavanant, Aunchalee Thanwisai, Apichat Vitta.
      Entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis have been considered to be effective biological control agents for several insects. In this study, we isolated and identified EPNs from soil samples in agricultural areas of northern Thailand and evaluated their efficacy for controlling larvae of three mosquito vector species, Aedes aegypti, Ae. albopictus and Culex quinquefasciatus. A total of 51 of 1,000 soil samples were positive (5.1% prevalence) for EPNs, which were identified through sequencing of the rDNA and ITS to 37 Steinernema isolates (3.7%) and 14 Heterorhabditis isolates (1.4%). For the bioassay, the larvae of mosquitoes were exposed to Steinernema surkhetense (eALN6.3_TH), Steinernema lamjungense (eALN11.5_TH), Heterorhabditis indica (eACM14.2_TH) and Heterorhabditis bacteriophora (eALN18.2_TH). Heterorhabditis bacteriophora showed the highest efficacy against Ae. aegypti and Cx. quinquefasciatus. At 96 h after exposure, the mortality rates were 60.0 and 91.7%, respectively. The EPNs were observed in the dead mosquito larvae, which were mostly found in the thorax followed by the head and abdomen. Some EPNs were dead with melanization, and some were able to survive in the cavity of mosquito larvae. Our results show the low prevalence of EPN in agricultural areas of Thailand. Moreover, H. bacteriophora may be considered an alternative biocontrol agent for managing and controlling these vector mosquitoes.
    Keywords:  Agricultural area; Biological control; Culicine mosquito; Heterorhabditis; Steinernema
    DOI:  https://doi.org/10.1016/j.actatropica.2023.106842
  3. Glob Health Action. 2023 Dec 31. 16(1): 2166650
    Impact of randomised wmel Wolbachia deployments on notified dengue cases and insecticide fogging for dengue control in Yogyakarta City.
    Citra Indriani, Stephanie K Tanamas, Uswatun Khasanah, Muhammad Ridwan Ansari, Rubangi, Warsito Tantowijoyo, Riris Andono Ahmad, Suzanne M Dufault, Nicholas P Jewell, Adi Utarini, Cameron P Simmons, Katherine L Anders.
       BACKGROUND: Releases of Wolbachia (wMel)-infected Aedes aegypti mosquitoes significantly reduced the incidence of virologically confirmed dengue in a previous cluster randomised trial in Yogyakarta City, Indonesia. Following the trial, wMel releases were extended to the untreated control areas, to achieve city-wide coverage of Wolbachia.
    OBJECTIVE: In this predefined analysis, we evaluated the impact of the wMel deployments in Yogyakarta on dengue hemorrhagic fever (DHF) case notifications and on the frequency of perifocal insecticide spraying by public health teams.
    METHODS: Monthly counts of DHF cases notified to the Yogyakarta District Health Office between January 2006 and May 2022 were modelled as a function of time-varying local wMel treatment status (fully- and partially-treated vs untreated, and by quintile of wMel prevalence). The frequency of insecticide fogging in wMel-treated and untreated areas was analysed using negative binomial regression.
    RESULTS: Notified DHF incidence was 83% lower in fully treated vs untreated periods (IRR 0.17 [95% CI 0.14, 0.20]), and 78% lower in areas with 80-100% wMel prevalence compared to areas with 0-20% wMel (IRR 0.23 [0.17, 0.30]). A similar intervention effect was observed at 60-80% wMel prevalence as at 80-100% prevalence (76% vs 78% efficacy, respectively). Pre-intervention, insecticide fogging occurred at similar frequencies in areas later randomised to wMel-treated and untreated arms of the trial. After wMel deployment, fogging occurred significantly less frequently in treated areas (IRR 0.17 [0.10, 0.30]).
    CONCLUSIONS: Deployments of wMel-infected Aedes aegypti mosquitoes resulted in an 83% reduction in the application of perifocal insecticide spraying, consistent with lower dengue case notifications in wMel-treated areas. These results show that the Wolbachia intervention effect demonstrated previously in a cluster randomised trial was also measurable from routine surveillance data.
    Keywords:  Aedes aegypti; Dengue; Wolbachia; vector control; wMel
    DOI:  https://doi.org/10.1080/16549716.2023.2166650
  4. Parasit Vectors. 2023 Jan 26. 16(1): 34
    Seasonal changes in the diversity, host preferences and infectivity of mosquitoes in two arbovirus-endemic regions of Costa Rica.
    Luis M Romero-Vega, Marta Piche-Ovares, Claudio Soto-Garita, Daniel Felipe Barantes Murillo, Luis Guillermo Chaverri, Alejandro Alfaro-Alarcón, Eugenia Corrales-Aguilar, Adriana Troyo.
       BACKGROUND: Mosquitoes are vectors of various arboviruses belonging to the genera Alphavirus and Flavivirus, and Costa Rica is endemic to several of them. The aim of this study was to describe and analyze the community structure of such vectors in Costa Rica.
    METHODS: Sampling was performed in two different coastal locations of Costa Rica with evidence of arboviral activity during rainy and dry seasons. Encephalitis vector surveillance traps, CDC female gravid traps and ovitraps were used. Detection of several arboviruses by Pan-Alpha and Pan-Flavi PCR was attempted. Blood meals were also identified. The Normalized Difference Vegetation Index (NDVI) was estimated for each area during the rainy and dry seasons. The Chao2 values for abundance and Shannon index for species diversity were also estimated.
    RESULTS: A total of 1802 adult mosquitoes belonging to 55 species were captured, among which Culex quinquefasciatus was the most caught species. The differences in NDVI were higher between seasons and between regions, yielding lower Chao-Sørensen similarity index values. Venezuelan equine encephalitis virus, West Nile virus and Madariaga virus were not detected at all, and dengue virus and Zika virus were detected in two separate Cx. quinquefasciatus specimens. The primary blood-meal sources were chickens (60%) and humans (27.5%). Both sampled areas were found to have different seasonal dynamics and population turnover, as reflected in the Chao2 species richness estimation values and Shannon diversity index.
    CONCLUSION: Seasonal patterns in mosquito community dynamics in coastal areas of Costa Rica have strong differences despite a geographical proximity. The NDVI influences mosquito diversity at the regional scale more than at the local scale. However, year-long continuous sampling is required to better understand local dynamics.
    Keywords:  Alphavirus; Diversity; Flavivirus; Mosquito; NDVI
    DOI:  https://doi.org/10.1186/s13071-022-05579-y
  5. Curr Res Insect Sci. 2022 ;2 100047
    A comparative analysis of Aedes albopictus and Aedes aegypti subjected to diapause-inducing conditions reveals conserved and divergent aspects associated with diapause, as well as novel genes associated with its onset.
    Diego Felipe Araujo Diniz, Tatiany Patrícia Romão, Elisama Helvécio, Danilo de Carvalho-Leandro, Morgana do Nascimento Xavier, Christina Alves Peixoto, Osvaldo Pompílio de Melo Neto, Maria Alice Varjal de Melo-Santos, Constância Flávia Junqueira Ayres.
      Aedes albopictus and Aedes aegypti are mosquito species that are distributed worldwide and transmit diverse arboviruses of medical importance, such as those causing yellow fever, dengue, chikungunya and Zika. A. albopictus embryos may remain viable for long periods in the environment due to their ability to become dormant through quiescence or diapause, a feature that contributes to their dispersion and hinders control actions. Diapause incidence can vary among natural populations of A. albopictus, but metabolic and genetic parameters associated with its induction still need to be better defined. The present study aimed to investigate the effect of exposure to diapause-inducing conditions on several biological parameters in different populations of A. albopictus (from tropical and temperate areas) and the diapause-refractory A. aegypti (tropical and subtropical populations). As expected, only the A. albopictus populations exhibited diapause, but with a lower incidence for the population from a tropical area. Exposure to diapause-inducing conditions, however, led to a sharp reduction in fecundity for both A. albopictus and A. aegypti tropical populations, with no effect on fertility (>90%). It also led to a prolonged period as pupae for the progeny of all induced groups, with a further delay for those from temperate climates. In all those induced groups, the lipid contents in eggs and adult females were higher than in the non-induced controls, with the highest values observed for both A. albopictus groups. Three genes were selected to have their expression profile investigated: cathepsin, idgf4, and pepck. Upon exposure to diapause-inducing conditions, all three genes were upregulated in the A. albopictus embryos from the tropical region, but only idgf4 was upregulated in the temperate climate embryos. This represents a new gene associated with diapause that can be used as a target to evaluate and prevent embryonic dormancy, a possible new vector control strategy for mosquito species from temperate areas, such as A. albopictus.
    Keywords:  adaptation; dormancy; eggs viability; embryogenesis; fitness cost
    DOI:  https://doi.org/10.1016/j.cris.2022.100047
  6. Lancet. 2023 Jan 24. pii: S0140-6736(22)02319-4. [Epub ahead of print]
    Efficacy of pyriproxyfen-pyrethroid long-lasting insecticidal nets (LLINs) and chlorfenapyr-pyrethroid LLINs compared with pyrethroid-only LLINs for malaria control in Benin: a cluster-randomised, superiority trial.
    Manfred Accrombessi, Jackie Cook, Edouard Dangbenon, Boulais Yovogan, Hilaire Akpovi, Arthur Sovi, Constantin Adoha, Landry Assongba, Aboubacar Sidick, Bruno Akinro, Razaki Ossè, Filémon Tokponnon, Rock Aïkpon, Aurore Ogouyemi-Hounto, Germain Gil Padonou, Immo Kleinschmidt, Louisa A Messenger, Mark Rowland, Corine Ngufor, Natacha Protopopoff, Martin C Akogbeto.
       BACKGROUND: New classes of long-lasting insecticidal nets (LLINs) combining mixtures of insecticides with different modes of action could put malaria control back on track after rebounds in transmission across sub-Saharan Africa. We evaluated the relative efficacy of pyriproxyfen-pyrethroid LLINs and chlorfenapyr-pyrethroid LLINs compared with standard LLINs against malaria transmission in an area of high pyrethroid resistance in Benin.
    METHODS: We conducted a cluster-randomised, superiority trial in Zou Department, Benin. Clusters were villages or groups of villages with a minimum of 100 houses. We used restricted randomisation to randomly assign 60 clusters to one of three LLIN groups (1:1:1): to receive nets containing either pyriproxyfen and alpha-cypermethrin (pyrethroid), chlorfenapyr and alpha-cypermethrin, or alpha-cypermethrin only (reference). Households received one LLIN for every two people. The field team, laboratory staff, analyses team, and community members were masked to the group allocation. The primary outcome was malaria case incidence measured over 2 years after net distribution in a cohort of children aged 6 months-10 years, in the intention-to-treat population. This study is ongoing and is registered with ClinicalTrials.gov, NCT03931473.
    FINDINGS: Between May 23 and June 24, 2019, 53 854 households and 216 289 inhabitants were accounted for in the initial census and included in the study. Between March 19 and 22, 2020, 115 323 LLINs were distributed to 54 030 households in an updated census. A cross-sectional survey showed that study LLIN usage was highest at 9 months after distribution (5532 [76·8%] of 7206 participants), but decreased by 24 months (4032 [60·6%] of 6654). Mean malaria incidence over 2 years after LLIN distribution was 1·03 cases per child-year (95% CI 0·96-1·09) in the pyrethroid-only LLIN reference group, 0·84 cases per child-year (0·78-0·90) in the pyriproxyfen-pyrethroid LLIN group (hazard ratio [HR] 0·86, 95% CI 0·65-1·14; p=0·28), and 0·56 cases per child-year (0·51-0·61) in the chlorfenapyr-pyrethroid LLIN group (HR 0·54, 95% CI 0·42-0·70; p<0·0001).
    INTERPRETATION: Over 2 years, chlorfenapyr-pyrethroid LLINs provided greater protection from malaria than pyrethroid-only LLINs in an area with pyrethroid-resistant mosquitoes. Pyriproxyfen-pyrethroid LLINs conferred protection similar to pyrethroid-only LLINs. These findings provide crucial second-trial evidence to enable WHO to make policy recommendations on these new LLIN classes. This study confirms the importance of chlorfenapyr as an LLIN treatment to control malaria in areas with pyrethroid-resistant vectors. However, an arsenal of new active ingredients is required for successful long-term resistance management, and additional innovations, including pyriproxyfen, need to be further investigated for effective vector control strategies.
    FUNDING: UNITAID, The Global Fund.
    DOI:  https://doi.org/10.1016/S0140-6736(22)02319-4
  7. Lancet. 2023 Jan 24. pii: S0140-6736(23)00102-2. [Epub ahead of print]
    Getting ahead of insecticide-resistant malaria vector mosquitoes.
    Gerry F Killeen, Seynabou Sougoufara.
      
    DOI:  https://doi.org/10.1016/S0140-6736(23)00102-2
  8. BMC Public Health. 2023 Jan 25. 23(1): 168
    "A comparative analysis of risk factors of malaria" case study Gisagara and Bugesera District of Rwanda. RDHS 2014/2015. A retrospective study.
    Emmanuel Kubana, Athanase Munyaneza, Steven Sande, Felix Nduhuye, Jean Bosco Karangwa, David Mwesigye, Emmanuel Ndagijimana, Samuel Habimana, Cyprien Munyanshongore.
       BACKGROUND: Malaria is a public health concern worldwide. A figure of 3.2 billion people is at risk of malaria a report of World Health Organization in 2013. A proportion of 89 and 91 cases of malaria reported during 2015 were respectively attributed to malaria cases and malaria deaths in Sub-Saharan Africa. Rwanda is among the Sub-Saharan Africa located in East Africa. The several reports indicate that from 2001 to 2011, malaria cases increased considerably especially in Eastern and Southern Province with five million cases. The affected districts included Bugesera in the Eastern and Gisagara in the Southern Province of Rwanda with a share of 41% of the country prevalence in 2014 and during 2017-2018 a figure of 11 deaths was attributed to malaria and both Gisagara and Bugesera Districts were the high burdened.
    METHODOLOGY: The RDHS 2014-2015 data was used for the study and a cross-sectional survey was used in which two clusters were considered both Gisagara and Bugesera Districts in the Southern and Eastern Province of Rwanda. Bivariate analysis was used to determine the significant predictors with malaria and reduced logistic regression model was used.
    RESULTS: The results of the study show that not having mosquito bed nets for sleeping is 0.264 times less likely of having malaria than those who have mosquito bed nets in Gisagara District. In Bugesera District, living in low altitude is 2.768 times more likely associated with the risk of getting malaria than living in high altitude.
    CONCLUSION: The results of the study concluded that environmental and geographical factor such as low altitude is the risk factor associated with malaria than the high altitude in Bugesera District. While not having mosquito bed nets for sleeping is the protective factor for malaria than those who have it in Gisagara District. On the other hand, socio-economic and demographic characteristics do not have any effect with malaria on the results of the study.
    Keywords:  CHWs; ICCM IRS; LLITN; Malaria; RDHS 2014/2015; Reduced logistic regression; Rwanda
    DOI:  https://doi.org/10.1186/s12889-023-15104-0
  9. Am J Trop Med Hyg. 2023 Jan 23. pii: tpmd220523. [Epub ahead of print]
    Prediction of the Risk Distributions for Anopheles sinensis, a Vector for Malaria in Shanghai, China.
    Yi-Xin Tong, Zhi-Gui Xia, Qiao-Yan Wang, Ning Xu, Hong-Lin Jiang, Zheng-Zhong Wang, Ying Xiong, Jiang-Fan Yin, Jun-Hui Huang, Feng Jiang, Yue Chen, Qing-Wu Jiang, Yi-Biao Zhou.
      Malaria is a parasitic disease caused by Plasmodium, and Anopheles sinensis is a vector of malaria. Although malaria is no longer indigenous to China, a high risk remains for local transmission of imported malaria. This study aimed to identify the risk distribution of vector An. sinensis and malaria transmission. Using data collected from routine monitoring in Shanghai from 2010 to 2020, online databases for An. sinensis and malaria, and environmental variables including climate, geography, vegetation, and hosts, we constructed 10 algorithms and developed ensemble models. The ensemble models combining multiple algorithms (An. sinensis: area under the curve [AUC] = 0.981, kappa = 0.920; malaria: AUC = 0.959, kappa = 0.800), with the best out-of-sample performance, were used to identify important environmental predictors for the risk distributions of An. sinensis and malaria transmission. For An. sinensis, the most important predictor in the ensemble model was moisture index, which reflected degree of wetness; the risk of An. sinensis decreased with higher degrees of wetness. For malaria transmission, the most important predictor in the ensemble model was the normalized differential vegetation index, which reflected vegetation cover; the risk of malaria transmission decreased with more vegetation cover. Risk levels for An. sinensis and malaria transmission for each district of Shanghai were presented; however, there was a mismatch between the risk classification maps of An. sinensis and malaria transmission. Facing the challenge of malaria transmission in Shanghai, in addition to precise An. sinensis monitoring in risk areas of malaria transmission, malaria surveillance should occur even in low-risk areas for An. sinensis.
    DOI:  https://doi.org/10.4269/ajtmh.22-0523
  10. Euro Surveill. 2023 Jan;28(2):
    Dengue, chikungunya and Zika virus infections among Dutch travellers to Suriname: a prospective study during the introduction of chikungunya and Zika virus, 2014 to 2017.
    Femke W Overbosch, Janke Schinkel, Amy Matser, Gerrit Koen, Irene Prange, Maria Prins, Gerard Jb Sonder.
      BackgroundSuriname, a country endemic for dengue virus (DENV), is a popular destination for Dutch travellers visiting friends and relatives and tourist travellers. Chikungunya and Zika virus (CHIKV, ZIKV) were introduced in 2014 and 2015, respectively. Data on infection risks among travellers are limited.AimWe aimed to prospectively study incidence rate (IR) and determinants for DENV, ZIKV and CHIKV infection in adult travellers to Suriname from 2014 through 2017.MethodsParticipants kept a travel diary and were tested for anti-DENV, anti-ZIKV and anti-CHIKV IgG antibodies (Euroimmun). Selected samples were subjected to an in-house DENV and ZIKV PRNT50. The IR (infections/1,000 person-months of travel) and IR ratio and determinants for infection were calculated.ResultsTravel-acquired infections were found in 21 of 481 participants: 18 DENV, four ZIKV and two CHIKV, yielding an IRDENV of 47.0 (95% CI: 29.6-74.6), IRZIKV of 11.6 (95% CI: 4.4-31.0) and IRCHIKV of 5.6 (95% CI: 1.4-22.2)/1,000 person-months. In nine DENV and three ZIKV infected participants, infections were PRNT50-confirmed, yielding a lower IRDENV of 23.3 (95% CI: 12.1-44.8) and an IRZIKV of 8.4 (95% CI: 2.7-26.1) per 1,000 person-months. Tourist travel was associated with DENV infection. ZIKV and CHIKV infections occurred soon after their reported introductions.ConclusionsDespite an overestimation of serologically confirmed infections, Dutch travellers to Suriname, especially tourists, are at substantial risk of DENV infection. As expected, the risk of contracting ZIKV and CHIKV was highest during outbreaks. Cross-reaction and potential cross-protection of anti-DENV and -ZIKV antibodies should be further explored.
    Keywords:  Suriname; Zika virus infections; chikungunya virus infections; dengue virus infections; prospective; travellers
    DOI:  https://doi.org/10.2807/1560-7917.ES.2023.28.2.2200344
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