bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2023‒02‒19
ten papers selected by
Richard Halfpenny, Staffordshire University
  1. A molecular surveillance-guided vector control response to concurrent dengue and West Nile virus outbreaks in a COVID-19 hotspot of Florida.
  2. Insecticide Resistance Status of Aedes albopictus (Diptera: Culicidae) Populations from Cuba.
  3. A Globally Distributed Insecticide Resistance Allele Confers a Fitness Cost in the Absence of Insecticide in Aedes aegypti (Diptera: Culicidae), the Yellow Fever Mosquito.
  4. Seasonal dynamics of Anopheles stephensi and its implications for mosquito detection and emergent malaria control in the Horn of Africa.
  5. Rapid range shifts in African Anopheles mosquitoes over the last century.
  6. Rising cases of Dengue and Malaria in Flood Affected Areas of Pakistan: A Major Threat to the Country's Healthcare System.
  7. Mapping and characterizing areas with high levels of malaria in pregnancy in Brazil: A spatiotemporal analysis.
  8. Why are there no human West Nile virus outbreaks in South America?
  9. A case-control study to determine the effectiveness of a tetravalent dengue vaccine in the state of Paraná, Brazil.
  10. Malaria Frontline Project: strategic approaches to improve malaria control program leveraging experiences from Kano and Zamfara States, Nigeria, 2016-2019.
  1. Lancet Reg Health Am. 2022 Jul;11 100231
    A molecular surveillance-guided vector control response to concurrent dengue and West Nile virus outbreaks in a COVID-19 hotspot of Florida.
    Heather Coatsworth, Catherine A Lippi, Chalmers Vasquez, Jasmine B Ayers, Caroline J Stephenson, Christy Waits, Mary Florez, André B B Wilke, Isik Unlu, Johana Medina, Sadie J Ryan, John A Lednicky, John C Beier, William Petrie, Rhoel R Dinglasan.
      Background: Simultaneous dengue virus (DENV) and West Nile virus (WNV) outbreaks in Florida, USA, in 2020 resulted in 71 dengue virus serotype 1 and 86 WNV human cases. We hypothesized that we would find a number of DENV-1 positive mosquito pools, and that the distribution of these arbovirus-positive mosquito pools would be associated with those neighborhoods for which imported DENV cases have been recently reported in 2019 and 2020.Methods: We collected and screened Aedes aegypti, Ae. albopictus, Anopheles crucians, Culex coronator, Cx. nigripalpus, and Cx. quinquefasciatus mosquitoes from Miami-Dade County (Florida) for DENV and WNV by rRT-qPCR. Spatial statistical analyses were performed to capture positive mosquito pool distribution in relation to land use, human demography, environmental variables, mosquito trap placement and reported human travel associated DENV cases to guide future mosquito control outbreak responses.
    Findings: A rapid screen of 7,668 mosquitoes detected four DENV serotype 2 (DENV-2), nine DENV-4 and nine WNV-positive mosquito pools, which enabled swift and targeted abatement of trap sites by mosquito control. As expected, DENV-positive pools were in urban areas; however, we found WNV-positive mosquito pools in agricultural and recreational areas with no historical reports of WNV transmission.
    Interpretation: These findings demonstrate the importance of proactive arbovirus surveillance in mosquito populations to prevent and control outbreaks, particularly when other illnesses (e.g., COVID-19), which present with similar symptoms, are circulating concurrently. Growing evidence for substantial infection prevalence of dengue in mosquitoes in the absence of local index cases suggests a higher level of dengue endemicity in Florida than previously thought.
    Funding: This research was supported in part by U.S. Centers for Disease Control and Prevention (CDC) grant 1U01CK000510-03, Southeastern Regional Center of Excellence in Vector Borne Diseases Gateway Program.
    Keywords:  Arboviruses; COVID-19; Dengue virus; Disease outbreaks; Disease vectors; West Nile virus
    DOI:  https://doi.org/10.1016/j.lana.2022.100231
  2. J Med Entomol. 2023 Feb 15. pii: tjac189. [Epub ahead of print]
    Insecticide Resistance Status of Aedes albopictus (Diptera: Culicidae) Populations from Cuba.
    Luis Augusto Piedra, Maria Magdalena Rodriguez, Isabel Lopez, Armando Ruiz, Liss Claudia Martinez, Israel Garcia, Jorge Rey, Juan Andres Bisset.
      Aedes albopictus (Skuse, 1894) is one of the major vectors for arboviruses such as dengue, Zika, and chikungunya. Originally from Southeast Asia, this species has spread to Africa, Europe, and the Americas, including Cuba. This spread has been favored by its great adaptability to variable temperatures and to the resistance of its eggs to desiccation. Chemical control of mosquitoes is an essential alternative to stop arbovirus transmission, but insecticide resistance status of the Cuban Ae. albopictus populations is unknown. For this study, Ae. albopictus larvae and adults were collected from two municipalities in Havana, Cuba in 2019. Adult bioassays for deltamethrin, cypermethrin, lambda-cyhalothrin, chlorpyrifos, propoxur, and bendiocarb susceptibility were conducted according to CDC methodology. Larval bioassays for temephos susceptibility were performed following WHO protocols. Resistance profiles for α and β-esterases, glutathione S-transferase (GST), and multifunction oxidases (MFO) pathways were constructed and analyzed. Resistance to temephos and deltamethrin was detected in Mulgoba and Plaza field populations, but resistance to lambda-cyhalothrin was only found in the Plaza colony. Plaza colony exhibited a higher expression level to all four metabolic enzymes and α-esterases and GTS were over-expressed in Mulgoba. The development of insecticide resistance in Cuban Ae. albopictus populations makes it imperative that we develop integrated control strategies to minimize the development of resistance and provide effective vector control that prevents the onset of arbovirus epidemics.
    Keywords:   Aedes albopictus ; insecticide; mosquito; resistance
    DOI:  https://doi.org/10.1093/jme/tjac189
  3. J Med Entomol. 2023 Feb 17. pii: tjad015. [Epub ahead of print]
    A Globally Distributed Insecticide Resistance Allele Confers a Fitness Cost in the Absence of Insecticide in Aedes aegypti (Diptera: Culicidae), the Yellow Fever Mosquito.
    Cera R Fisher, Anastacia E Dressel, Juan J Silva, Jeffrey G Scott.
      The cosmopolitan mosquito Aedes aegypti is a vector of harmful arboviruses. Pyrethroid insecticides are used to reduce adult populations and prevent the spread of disease. Pyrethroids target the insect voltage-gated sodium channel (VGSC). Collectively, mutations in Vgsc that confer resistance are referred to as knock-down resistance or kdr. There are numerous kdr mutations found in A. aegypti Vgsc, and there is co-occurrence of some mutations. Full-length cDNA sequences have identified nine known kdr (e.g., 1534C) alleles. The 1534C allele is among the most common kdr alleles, but allele frequencies between populations vary considerably. We used the 1534C:RK strain, which has the 1534C (kdr) allele in the genetic background of the insecticide susceptible Rockefeller (ROCK) strain, and conducted population cage experiments to assess the potential intrinsic fitness cost of the 1534C allele relative to the susceptible allele (F1534) in the ROCK strain. Individuals were genotyped across generations using allele specific PCR. A fitness cost of the 1534C allele was detected across seven generations of mosquitos reared in the absence of insecticide selection pressure. The decrease in allele frequency was not due to drift. Comparison of our results to previous studies suggests that the magnitude of the fitness cost of kdr alleles in the absence of insecticide is disconnected from the level of resistance they confer, and that the fitness costs of different kdr alleles can be variable.
    Keywords:   Aedes aegypti ; fitness cost; insecticide resistance; knockdown resistance allele
    DOI:  https://doi.org/10.1093/jme/tjad015
  4. Proc Natl Acad Sci U S A. 2023 Feb 21. 120(8): e2216142120
    Seasonal dynamics of Anopheles stephensi and its implications for mosquito detection and emergent malaria control in the Horn of Africa.
    Charles Whittaker, Arran Hamlet, Ellie Sherrard-Smith, Peter Winskill, Gina Cuomo-Dannenburg, Patrick G T Walker, Marianne Sinka, Samuel Pironon, Ashwani Kumar, Azra Ghani, Samir Bhatt, Thomas S Churcher.
      Invasion of the malaria vector Anopheles stephensi across the Horn of Africa threatens control efforts across the continent, particularly in urban settings where the vector is able to proliferate. Malaria transmission is primarily determined by the abundance of dominant vectors, which often varies seasonally with rainfall. However, it remains unclear how An. stephensi abundance changes throughout the year, despite this being a crucial input to surveillance and control activities. We collate longitudinal catch data from across its endemic range to better understand the vector's seasonal dynamics and explore the implications of this seasonality for malaria surveillance and control across the Horn of Africa. Our analyses reveal pronounced variation in seasonal dynamics, the timing and nature of which are poorly predicted by rainfall patterns. Instead, they are associated with temperature and patterns of land use; frequently differing between rural and urban settings. Our results show that timing entomological surveys to coincide with rainy periods is unlikely to improve the likelihood of detecting An. stephensi. Integrating these results into a malaria transmission model, we show that timing indoor residual spraying campaigns to coincide with peak rainfall offers little improvement in reducing disease burden compared to starting in a random month. Our results suggest that unlike other malaria vectors in Africa, rainfall may be a poor guide to predicting the timing of peaks in An. stephensi-driven malaria transmission. This highlights the urgent need for longitudinal entomological monitoring of the vector in its new environments given recent invasion and potential spread across the continent.
    Keywords:  Anopheles stephensi; epidemiology; malaria ecology; population dynamics; urban malaria
    DOI:  https://doi.org/10.1073/pnas.2216142120
  5. Biol Lett. 2023 Feb;19(2): 20220365
    Rapid range shifts in African Anopheles mosquitoes over the last century.
    Colin J Carlson, Ellen Bannon, Emily Mendenhall, Timothy Newfield, Shweta Bansal.
      Facing a warming climate, many tropical species-including the arthropod vectors of several infectious diseases-will be displaced to higher latitudes and elevations. These shifts are frequently projected for the future, but rarely documented in the present day. Here, we use one of the most comprehensive datasets ever compiled by medical entomologists to track the observed range limits of African malaria mosquito vectors (Anopheles spp.) from 1898 to 2016. Using a simple regression approach, we estimate that these species' ranges gained an average of 6.5 m of elevation per year, and the southern limits of their ranges moved polewards 4.7 km per year. These shifts would be consistent with the local velocity of recent climate change, and might help explain the incursion of malaria transmission into new areas over the past few decades. Confirming that climate change underlies these shifts, and applying similar methods to other disease vectors, are important directions for future research.
    Keywords:  Anopheles; climate change; geographical range shift; malaria
    DOI:  https://doi.org/10.1098/rsbl.2022.0365
  6. Disaster Med Public Health Prep. 2023 Feb 15. 17 e323
    Rising cases of Dengue and Malaria in Flood Affected Areas of Pakistan: A Major Threat to the Country's Healthcare System.
    Laiba Imran Vohra, Muhammad Aqib, Hassan Jamal, Qasim Mehmood, Fatima Yasin.
      
    Keywords:  dengue; floods; malaria; mosquitoes
    DOI:  https://doi.org/10.1017/dmp.2022.293
  7. Lancet Reg Health Am. 2022 Aug;12 100285
    Mapping and characterizing areas with high levels of malaria in pregnancy in Brazil: A spatiotemporal analysis.
    Jamille Gregório Dombrowski, Laura Cordeiro Gomes, Camila Lorenz, Raquel Gardini Sanches Palasio, Paola Marchesini, Sabrina Epiphanio, Claudio Romero Farias Marinho.
      Background: Malaria in pregnancy (MiP) is a public health problem in the Brazilian Amazon region that requires special attention due to associated serious adverse consequences, such as low birth weight, increased prematurity and spontaneous abortion rates. In Brazil, there have been no comprehensive epidemiological studies of MiP. In this study, we aimed to explore the spatial and spatiotemporal patterns of MiP in Brazil and epidemiologically characterize this population of pregnant women over a period of 15 years.Methods: We performed a national-scale ecological analysis using a Bayesian space-time hierarchical model to estimate the incidence rates of MiP between 1 January 2004 and 31 December 2018. We mapped the high-incidence clusters among pregnant women aged 10-49 years old using a Poisson model, and we characterized the population based on data from the Epidemiological Surveillance Information System for Malaria (SIVEP-Malaria).
    Findings: We consolidated the data of 61,833 women with MiP in Brazil. Our results showed a reduction of 50·1% (95% CI: 47·3 to 52·9) in the number of malaria cases over the period analysed, with Plasmodium vivax malaria having the highest incidence. MiP was widely distributed throughout the Amazon region, and spatial and spatiotemporal analyses revealed statistically significant clusters in some municipalities of Amazonas, Acre, Rondônia and Pará. In addition, we observed that younger pregnant women had a higher risk of infection, and the administration of appropriate treatment requires more attention.
    Interpretation: This nationwide study provides robust evidence that, despite the reduction in the number of MiP cases in the country, it remains a serious public health problem, especially for young pregnant women. Our analyses highlight focus areas for strengthening interventions to control and eliminate MiP.
    Funding: FAPESP and CNPq - Brazil.
    Keywords:  Brazil; Epidemiology; Malaria; P. falciparum; P. vivax; Pregnancy
    DOI:  https://doi.org/10.1016/j.lana.2022.100285
  8. Lancet Reg Health Am. 2022 Aug;12 100276
    Why are there no human West Nile virus outbreaks in South America?
    Camila Lorenz, Francisco Chiaravalloti-Neto.
      
    DOI:  https://doi.org/10.1016/j.lana.2022.100276
  9. Lancet Reg Health Am. 2022 Mar;7 100141
    A case-control study to determine the effectiveness of a tetravalent dengue vaccine in the state of Paraná, Brazil.
    José Cássio de Moraes, Irina Nastassja Riediger, Fernanda Crosewski, Denise Oliveira Garrett, Francieli Fontana Fantinato, Karina Braga Ribeiro, Expedito José de Albuquerque Luna.
      Background: The Brazilian state of Paraná conducted a mass vaccination campaign against dengue with the tetravalent attenuated vaccine CYD-TDV. The campaign targeted thirty endemic municipalities. The objective of this study was to assess the effectiveness of CYD-TDV in preventing symptomatic virologically confirmed dengue cases according to specific age groups in five of the municipalities.Methods: A case-control study was carried out in the five most populous municipalities targeted by the vaccination, with a vaccine uptake of 25%. Symptomatic dengue cases were identified by the municipal health departments. The age groups targeted were 15-18 and 19-27 in four municipalities and 9-14 and 28-44 in one municipality. All cases were confirmed by real time reverse transcription quantitative polymerase chain reaction (RT-qPCR). For each case, two controls were selected: a neighbourhood control and a workplace or school/college control, matched by age group. A conditional logistic regression model was used to determine the odds ratio for vaccination and the vaccine effectiveness.
    Findings: Study participants included 618 RT-qPCR-confirmed dengue cases and 1,236 matched controls (with a non-reactive dengue IgM serologic test). Vaccine effectiveness against dengue due to any serotype was 11·1% (95% CI: -19·0%; 33·6%). Effectiveness against DENV-1 was 33·3% (95% CI: -5·0%; 57·6%) and against DENV-2 was -56·7% (95% CI: -142·2%; -5·0%). No DENV-3 was detected. The vaccine was significantly effective in the prevention of DENV-4 cases (VE = 93·3%; 95% CI: 47·7%; 99·2%).
    Interpretation: CYD-TDV was effective in the prevention of symptomatic cases due to DENV-4, but not due to any serotype. The low dengue seroprevalence in the target population could possibly be related to these results.
    Funding: This study was supported through a grant to the Sabin Vaccine Institute from Sanofi-Pasteur. Sanofi-Pasteur had no role in the study design, protocol development, data collection, analysis, or publication of results.
    Keywords:  Brazil; CYD-TDV; Paraná; dengue; vaccine effectiveness
    DOI:  https://doi.org/10.1016/j.lana.2021.100141
  10. BMC Health Serv Res. 2023 Feb 11. 23(1): 147
    Malaria Frontline Project: strategic approaches to improve malaria control program leveraging experiences from Kano and Zamfara States, Nigeria, 2016-2019.
    Adefisoye Adewole, Olufemi Ajumobi, Ndadilnasiya Waziri, Amina Abdullahi Umar, Usaini Bala, Saheed Gidado, Gideon Ugbenyo, Edwin Simple, Isaac Igbaver, Adam Attahiru, Charles A Michael, Belinda Uba, Patrick Nguku, Perpetua Uhomoibhi, Basheer Muhammad, Munira Ismael, Shelby Cash, John Williamson, Peter McElroy, Stephen Patrick Kachur, Kwame Asamoa.
      BACKGROUND: The Malaria Frontline Project (MFP) supported the National Malaria Elimination Program for effective program implementation in the high malaria-burden states of Kano and Zamfara adapting the National Stop Transmission of Polio (NSTOP) program elimination strategies.PROJECT IMPLEMENTATION: The MFP was implemented in 34 LGAs in the two states (20 out of 44 in Kano and all 14 in Zamfara). MFP developed training materials and job aids tailored to expected service delivery for primary and district health facilities and strengthened supportive supervision. Pre- and post-implementation assessments of intervention impacts were conducted in both states.
    RESULTS: A total of 158 (Kano:83; Zamfara:75) and 180 (Kano:100; Zamfara:80) healthcare workers (HCWs), were interviewed for pre-and post-implementation assessments, respectively. The proportions of HCWs with correct knowledge on diagnostic criteria were Kano: 97.5% to 92.0% and Zamfara: 94.7% to 98.8%; and knowledge of recommended first line treatment of uncomplicated malaria were Kano: 68.7% to 76.0% and Zamfara: 69.3% to 65.0%. The proportion of HCWs who adhered to national guidelines for malaria diagnosis and treatment increased in both states (Kano: 36.1% to 73.0%; Zamfara: 39.2% to 67.5%) and HCW knowledge to confirm malaria diagnosis slightly decreased in Kano State but increased in Zamfara State (Kano: 97.5% to 92.0%; Zamfara: 94.8% to 98.8%). HCWs knowledge of correct IPTp drug increased in both states (Kano: 81.9% to 94.0%; Zamfara: 85.3% to 97.5%).
    CONCLUSION: MFP was successfully implemented using tailored training materials, job aids, supportive supervision, and data use. The project strategy can likely be adapted to improve the effectiveness of malaria program implementation in other Nigerian states, and other malaria endemic countries.
    Keywords:  Capacity building; Healthcare workers; Kano; Malaria Frontline Project; Malaria case management; Zamfara
    DOI:  https://doi.org/10.1186/s12913-023-09143-x
This page is being maintained by Thomas Krichel. It was last updated on 2023‒10‒25 at 12:20.