bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2022‒04‒03
thirteen papers selected by
Richard Halfpenny
Staffordshire University
  1. Seasonal variation and intra urban heterogeneity of the entomological risk of transmission of dengue and yellow fever in Abidjan, Côte d'Ivoire.
  2. Blood Feeding Patterns of Aedes aegypti Populations in Senegal.
  3. Fitness cost of malathion resistance in Egyptian Culex pipiens populations.
  4. Anopheles stephensi: a guest to watch in urban Africa.
  5. California Residents' Perceptions of Gene Drive Systems to Control Mosquito-Borne Disease.
  6. Zoonotic malaria transmission and land use change in Southeast Asia: what is known about the vectors.
  7. Effects of Guangzhou seasonal climate change on the development of Aedes albopictus and its susceptibility to DENV-2.
  8. Assessing Insecticide Susceptibility and Resistance Intensity of Anopheles gambiae s.l. Populations From Some Districts of Benin Republic, West Africa.
  9. Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX.
  10. Understudied Anophelines Contribute to Malaria Transmission in a Low-Transmission Setting in the Choma District, Southern Province, Zambia.
  11. Highland Malaria Transmission Dynamics in Space and Time Before Pre-elimination Era, Northwest Ethiopia.
  12. Circulation of zoonotic flaviviruses in wild passerine birds in Western Spain.
  13. Assessment of knowledge and their practices regarding malaria among members of Village Health Sanitation Committee in rural Uttar Pradesh: A cross-sectional study.
  1. Med Vet Entomol. 2022 Mar 30.
    Seasonal variation and intra urban heterogeneity of the entomological risk of transmission of dengue and yellow fever in Abidjan, Côte d'Ivoire.
    Négnorogo Guindo-Coulibaly, Mintokapieu Didier Stephane Kpan, Akré Maurice Adja, Affoué Mireille Nadia Kouadio, Konan Fabrice Assouho, Dounin Danielle Zoh, Konan Rodolphe Mardoché Azongnibo, Franck Remoue, Florence Fournet.
      Dengue and yellow fever are prevalent in Côte d'Ivoire and Aedes (Stegomyia) aegypti (Linnaeus), (Diptera: Culicidae), is known as the main vector. We aimed to assess seasonal variation and spatial heterogeneity in the transmission of both arbovirus diseases in Abidjan. Entomological surveys targeting larvae of A. aegypti, were carried out between November 2015 and August 2016 covering the four climatic seasons including a cohort of 100 houses randomly selected in three neighbourhoods. A. aegypti was the predominant species (96.6%) of mosquitoes resulting from the rearing of harvested larvae, and the only vector of dengue and yellow fever recorded during the study period. The highest proportion of water storage containers (45.5%) which represented the major breeding sites infested by the larvae of A. aegypti, was observed in Anoumabo. The house indices >5% and/or Breteau indices >20 recorded in each neighbourhood, during the different climatic seasons, indicated that there was, a high and permanent, heterogeneity in the transmission risk of dengue and yellow fever between the three neighbourhoods. In terms of transmission risk, Anoumabo was the neighbourhood with the highest risk compared to the two others, then, particular attention should be paid to this site in terms of surveillance by vector control programme in Abidjan.
    Keywords:  Abidjan; Aedes aegypti; Stegomyan indices; arboviruses; entomological risk
    DOI:  https://doi.org/10.1111/mve.12571
  2. Am J Trop Med Hyg. 2022 Mar 28. pii: tpmd210508. [Epub ahead of print]
    Blood Feeding Patterns of Aedes aegypti Populations in Senegal.
    Ndeye Marie Sene, Babacar Diouf, Alioune Gaye, El Hadji Ndiaye, Elhadj Malick Ngom, Assiyatou Gueye, Fatoumata Seck, Cheikh Tidiane Diagne, Ibrahima Dia, Diawo Diallo, Mawlouth Diallo.
      Aedes aegypti plays an important role in the transmission of several arboviruses of medical importance. The availability of information on the blood-feeding preferences of mosquito vectors is a critical step in the understanding of the transmission of human pathogens and implementation of control strategies. In Senegal, no data currently exist on the feeding pattern of Ae. aegypti in urban areas. To fill this gap, Ae. aegypti blood-fed females were collected in five localities by aspiration and using BG Sentinel 2 traps. Collections were carried out monthly between July and November 2019 inside and outside human dwellings. The origin of the blood meal of Ae. aegypti females were identified by an ELISA technique. A total of 1,710 blood-engorged females were examined and showed that Ae. aegypti preferentially fed on human with 78.6% of the identified blood meals. The other blood meals were from animals including dog, cat, horse, cattle, sheep, and rat. This is the first report on the feeding behavior of Ae. aegypti in urban settings in West Africa. It demonstrated that this species is highly anthropophilic.
    DOI:  https://doi.org/10.4269/ajtmh.21-0508
  3. Med Vet Entomol. 2022 Mar 31.
    Fitness cost of malathion resistance in Egyptian Culex pipiens populations.
    Noura A Elhawary, Mohamed A Soliman, Amal I Seif, Wesam S Meshrif.
      The extensive use of insecticides in agriculture and public health has resulted in the rapid development of insecticide resistance in mosquito populations. Therefore, in this study, we aimed to evaluate insecticide resistance costs on the fitness of Culex pipiens. Two Cx. pipiens field populations (Beheira malathion-resistant and Gharbia malathion-susceptible) were compared to the reference (sensitive) population. The biochemical composition and expression of four genes relevant to insecticide resistance were estimated in third instar larvae. Adult survival, female fecundity and egg hatchability were also determined. As per our findings, it was found that the total protein and carbohydrate contents in Beheira malathion-resistant larvae were significantly lower than that in the reference larvae. Beheira malathion-resistant larvae had higher phenoloxidase (PO) specific activity than the reference population. In terms of the relevant genes, only cytochrome P450 (CYP6F1) expression showed elevated levels in the Gharbia malathion-susceptible population compared to the Beheira malathion-resistant population. In esterases (Estα and Estβ) and glutathione S-transferase, the tested populations did not show any significant differences. Compared to the reference mosquito population, Gharbia malathion-susceptible Cx. pipiens males exhibited significantly longer median survival. Female fecundity and hatchability showed nonsignificant differences among the populations tested. In conclusion, malathion resistance can induce lower protein and carbohydrate contents, but higher PO activity in larvae.
    Keywords:  malathion; metabolic reserves; mosquitoes; resistance genes; survival
    DOI:  https://doi.org/10.1111/mve.12572
  4. Trop Dis Travel Med Vaccines. 2022 Apr 01. 8(1): 7
    Anopheles stephensi: a guest to watch in urban Africa.
    Eliningaya J Kweka.
      Malaria vector control programs in Sub-Saharan Africa have invested many efforts and resources in the control of eight-sibling species of Anopheles gambiae complex and An. funestus group. The behaviour of sibling species of these vectors is well known and used for implementing the current intervention tools. The reports of An. stephensi in urban Africa with different habitats breeding behaviour is an alert on the success of malaria vector control efforts achieved so far. This communication intends to give an insight on what should be considered as a challenge for the management of An. stephensi in urban Africa to retain the achievement attained in malaria control.
    Keywords:  Breeding sites; Habitat types; Insecticide; Malaria; Resistance
    DOI:  https://doi.org/10.1186/s40794-022-00165-7
  5. Front Bioeng Biotechnol. 2022 ;10 848707
    California Residents' Perceptions of Gene Drive Systems to Control Mosquito-Borne Disease.
    Cynthia E Schairer, Cynthia Triplett, Omar S Akbari, Cinnamon S Bloss.
      Scientists developing gene drive mosquitoes for vector control must understand how residents of affected areas regard both the problem of mosquito-borne disease and the potential solutions offered by gene drive. This study represents an experiment in public engagement at an early stage of technology development, intended to inform lab scientists about public attitudes toward their research and inspire consideration and conversation about the social ramifications of creating mosquitoes with gene drive. Online focus groups with California residents explored views on mosquito-borne disease risk, current mosquito control methods, and the proposed development and use of different classes of gene drives to control Ae. aegypti. Rather than a dogmatic rejection of genetic engineering or gene drive, many participants expressed pragmatic concerns with cost, control, the ability to narrowly target specific species, and the challenges of mistrust and institutional cooperation. Work like this can inform the alignment of community priorities and the professional priorities of scientists and vector control specialists.
    Keywords:  community and stakeholder engagement; gene drives; genetic engineering; public health; science communication; vector control
    DOI:  https://doi.org/10.3389/fbioe.2022.848707
  6. Malar J. 2022 Mar 31. 21(1): 109
    Zoonotic malaria transmission and land use change in Southeast Asia: what is known about the vectors.
    Bram van de Straat, Boni Sebayang, Matthew J Grigg, Kyran Staunton, Triwibowo Ambar Garjito, Indra Vythilingam, Tanya L Russell, Thomas R Burkot.
      Zoonotic Plasmodium infections in humans in many Southeast Asian countries have been increasing, including in countries approaching elimination of human-only malaria transmission. Most simian malarias in humans are caused by Plasmodium knowlesi, but recent research shows that humans are at risk of many different simian Plasmodium species. In Southeast Asia, simian Plasmodium species are mainly transmitted by mosquitoes in the Anopheles leucosphyrus and Anopheles dirus complexes. Although there is some evidence of species outside the Leucosphyrus Group transmitting simian Plasmodium species, these await confirmation of transmission to humans. The vectors of monkey malarias are mostly found in forests and forest fringes, where they readily bite long-tailed and pig-tailed macaques (the natural reservoir hosts) and humans. How changing land-uses influence zoonotic malaria vectors is still poorly understood. Fragmentation of forests from logging, agriculture and other human activities is associated with increased zoonotic Plasmodium vector exposure. This is thought to occur through altered macaque and mosquito distributions and behaviours, and importantly, increased proximity of humans, macaques, and mosquito vectors. Underlying the increase in vector densities is the issue that the land-use change and human activities create more oviposition sites and, in correlation, increases availably of human blood hosts. The current understanding of zoonotic malaria vector species is largely based on a small number of studies in geographically restricted areas. What is known about the vectors is limited: the data is strongest for distribution and density with only weak evidence for a limited number of species in the Leucosphyrus Group for resting habits, insecticide resistance, blood feeding habits and larval habitats. More data are needed on vector diversity and bionomics in additional geographic areas to understand both the impacts on transmission of anthropogenic land-use change and how this significant disease in humans might be controlled.
    Keywords:  Human land-use; Leucosphyrus Group; Mosquito vectors; Plasmodium knowlesi; Vector behaviour; Zoonotic malaria
    DOI:  https://doi.org/10.1186/s12936-022-04129-2
  7. PLoS One. 2022 ;17(4): e0266128
    Effects of Guangzhou seasonal climate change on the development of Aedes albopictus and its susceptibility to DENV-2.
    Shanshan Wu, Yulan He, Yong Wei, Peiyang Fan, Weigui Ni, Daibin Zhong, Guofa Zhou, Xueli Zheng.
      The susceptibility of Asian tiger mosquitoes to DENV-2 in different seasons was observed in simulated field environments as a reference to design dengue fever control strategies in Guangzhou. The life table experiments of mosquitoes in four seasons were carried out in the field. The susceptibility of Ae. albopictus to dengue virus was observed in both environments in Guangzhou in summer and winter. Ae. albopictus was infected with dengue virus by oral feeding. On day 7 and 14 after infection, the viral load in the head, ovary, and midgut of the mosquito was detected using real-time fluorescent quantitative PCR. Immune-associated gene expression in infected mosquitoes was performed using quantitative real-time reverse transcriptase PCR. The hatching rate and pupation rate of Ae. albopictus larvae in different seasons differed significantly. The winter hatching rate of larvae was lower than that in summer, and the incubation time was longer than in summer. In the winter field environment, Ae. albopictus still underwent basic growth and development processes. Mosquitoes in the simulated field environment were more susceptible to DENV-2 than those in the simulated laboratory environment. In the midgut, viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 14.459, P = 0.01); ovarian viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 8.656, P < 0.001), but there was no significant difference in the viral load at other time points (P > 0.05). Dicer-2 mRNA expression on day 7 in winter was 4.071 times than that on day 7 in summer: the viral load and Dicer-2 expression correlated moderately. Ae. albopictus could still develop and transmit dengue virus in winter in Guangzhou. Mosquitoes under simulated field conditions were more susceptible to DENV-2 than those under simulated laboratory conditions.
    DOI:  https://doi.org/10.1371/journal.pone.0266128
  8. J Med Entomol. 2022 Mar 31. pii: tjac037. [Epub ahead of print]
    Assessing Insecticide Susceptibility and Resistance Intensity of Anopheles gambiae s.l. Populations From Some Districts of Benin Republic, West Africa.
    Casimir Dossou Kpanou, Hermann W Sagbohan, Arthur Sovi, Razaki Osse, Gil G Padonou, Albert Salako, Filémon Tokponnon, Arsène Jacques Fassinou, Boulais Yovogan, Udoka C Nwangwu, Constantin J Adoha, Esdras Mahoutin Odjo, Idelphonse Ahogni, Aboubakar Sidick, Lamine Saïd Baba-Moussa, Martin Akogbéto.
      Pyrethroid resistance is widespread in sub-Saharan Africa. The objective of this study was to assess the insecticide resistance intensity in Anopheles gambiae s.l. (Diptera: Culicidae) in four districts of Benin in order to better understand how pyrethroid-only nets are likely to be effective. Thus, adult females of An. gambiae s.l., reared from field-collected larvae were used for assessing resistance intensity to permethrin and deltamethrin. They were tested at 1×, 5×, and 10× the diagnostic dose, using both WHO susceptibility tube testing and CDC bottle bioassays. Identification of molecular species, as well as of L1014F Kdr and Ace-1R mutations was performed using the PCR. The level of expression of biochemical enzymes was also evaluated. Overall, moderate to high resistance intensity to permethrin and deltamethrin was observed, irrespective of the testing method. While the L1014F Kdr frequency was high (>75%), Ace-1R was low (≤6%) in An. gambiaes.s. and Anopheles coluzzii, the two predominant species [52% (95% CI: 44.8-59.1) and 45% (95% CI: 38.0-52.2), respectively]. Anopheles arabiensis was found at very low frequency (3%, 95%CI: 1.1-6.4). For Biochemical analyses, α and β-esterases were over-expressed in all four districts, while mixed-function oxidases (MFOs) were over-expressed in only one. Overall, the two testing methods led to comparable conclusions, though there were a few inconsistencies between them. The moderate-high resistance intensity observed in the study area suggests that dual active-ingredient (AI) long-lasting insecticidal nets (LLINs) may provide better control of insecticide-resistant mosquitoes.
    Keywords:  CDC bottle bioassay; WHO susceptibility tube testing; pyrethroid; resistance intensity
    DOI:  https://doi.org/10.1093/jme/tjac037
  9. Sci Rep. 2022 Mar 29. 12(1): 5315
    Diel activity patterns of two distinct populations of Aedes aegypti in Miami, FL and Brownsville, TX.
    John-Paul Mutebi, André Barretto Bruno Wilke, Erik Ostrum, Chalmers Vasquez, Gabriel Cardenas, Augusto Carvajal, Maday Moreno, William D Petrie, Arturo Rodriguez, Henry Presas, Jesus Rodriguez, Fred Barnes, Gabriel L Hamer, Jose G Juarez, Ester Carbajal, Christopher J Vitek, Xochitl Estrada, Thalia Rios, Jeremy Marshall, John C Beier.
      The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using BG-Sentinel 2 Traps. The overall diel activity pattern in both cities was bimodal with morning and evening peak activity between 7:00 and 8:00 and between 19:00 and 20:00. There were significant daily, monthly, seasonal, and site-specific differences in activity patterns, but these differences did not affect the overall peak activity times. These differences suggest daily, monthly, seasonal, and site-specific variations in human exposure to Ae. aegypti. Our observations can be used in planning and executing Ae. aegypti vector control activities in southern Florida and southern Texas, specifically those targeting the adult mosquito populations.
    DOI:  https://doi.org/10.1038/s41598-022-06586-w
  10. Am J Trop Med Hyg. 2022 Mar 28. pii: tpmd210989. [Epub ahead of print]
    Understudied Anophelines Contribute to Malaria Transmission in a Low-Transmission Setting in the Choma District, Southern Province, Zambia.
    Southern and Central Africa International Center of Excellence for Malaria Research
      Malaria transmission has declined substantially in Southern Province, Zambia, which is considered a low-transmission setting. The Zambian government introduced a reactive test-and-treat strategy to identify active zones of transmission and treat parasitemic residents. This study was conducted in the Choma District, Southern Province, Zambia, concurrently with an evaluation of this strategy to identify vectors responsible for sustaining transmission, and to identify entomological, spatial, and ecological risk factors associated with increased densities of mosquitoes. Anophelines were collected with CDC light traps indoors and near animal pens in index cases and neighboring households. Outdoor collections captured significantly more anophelines than indoor traps, and 10 different anopheline species were identified. Four species (Anopheles arabiensis, An. rufipes, An. squamosus, and An. coustani) were positive for Plasmodium falciparum circumsporozoite protein by ELISA, and 61% of these 26 anophelines were captured outdoors. Bloodmeal assays confirm plasticity in An. arabiensis foraging, feeding both on humans and animals, whereas An. rufipes, An. squamosus, and An. coustani were largely zoophilic and exophilic. Linear regression of count data for indoor traps revealed that households with at least one parasitemic resident by polymerase chain reaction testing was associated with higher female anopheline counts. This suggests that targeting households with parasitemic individuals for vector interventions may reduce indoor anopheline populations. However, many vectors species responsible for transmission may not be affected by indoor interventions because they are primarily exophilic and forage opportunistically. These data underscore the necessity for further evaluation of vector surveillance and control tools that are effective outdoors, in conjunction with current indoor-based interventions.
    DOI:  https://doi.org/10.4269/ajtmh.21-0989
  11. J Epidemiol Glob Health. 2022 Mar 27.
    Highland Malaria Transmission Dynamics in Space and Time Before Pre-elimination Era, Northwest Ethiopia.
    Yalemwork Ewnetu, Wossenseged Lemma.
      BACKGROUND: Currently, the district-level malaria transmission stratification has indicated the Northern, Northwestern, Southern, and rift valley lowland and surrounding highland districts are almost entirely classified as high or moderate malaria transmission zones. Conducting malaria surveillance to track, test, and treat all malaria cases cannot be implemented in Ethiopia in the current situation.OBJECTIVE: To show malaria transmission dynamics in different health facilities located from 1800 to 2772 m altitudes during 2018-2021 in Northwest Ethiopia.
    METHODS: A total of 3.5 years (2018-2021) retrospective confirmed and treated malaria cases in 43 kebeles health posts and clinics in Gondar Zuria district were used for analysis.
    RESULT: The total malaria count was 5893 for 2019 compared to 31, 550 for 2020 and 33, 248 for 2021. Mean monthly malaria incidence/1000 people in 2019 was 2.39 ± 5.4 and increased to 10.64 ± 16.99 in 2020 and 11.19 ± 16.59 in 2021. Annual malaria incidence increased from 24 cases/1000 people in 2019 to 139.08 cases/1000 people in 2021 and is alarming danger in malaria elimination program in the district or the country as a whole. Poisson and Negative binomial regressions models indicated 5.78- and 5.26-fold malaria cases increase, respectively, in 2021 compared to 2019. The sudden increase in malaria incidences (counts) in 2020 and 2021 coincided with the interruption of residual insecticide application in Gondar Zuria district during the transition period towards the malaria pre-elimination stage implicating the role of malaria control tools in suppressing transmission. Study on climate variability also indicated that the rainfall variability in different months might have also favored high malaria transmission in 2020 and 2021 compared to 2019. Thus, in addition to re-starting the use of malaria control tools, giving attention to climate anomalies (variability) that favors malaria transmission, for prompt interventional actions, is required. The malaria elimination program in Ethiopia might have not reached a pre-elimination stage as malaria cases per 1000 people have not decreased below five in the majority of Ethiopian districts. Tracing, confirming, and treating individual cases to stop further transmission is, almost, impossible. In a situation like this, the Ethiopian malaria elimination program should work intensively towards understanding malaria epidemiology at the district level to re-design a localized malaria control strategy. The renewed malaria control program should also consider altitudes above 2000 m.
    Keywords:  Highland malaria; Malaria elimination program; Malaria transmission dynamics; Northwest Ethiopia
    DOI:  https://doi.org/10.1007/s44197-022-00034-8
  12. Vet Microbiol. 2022 Mar 22. pii: S0378-1135(22)00069-4. [Epub ahead of print]268 109399
    Circulation of zoonotic flaviviruses in wild passerine birds in Western Spain.
    A Marzal, M Ferraguti, J Muriel, S Magallanes, J A Ortiz, L García-Longoria, D Bravo-Barriga, F Guerrero-Carvajal, P Aguilera-Sepúlveda, F Llorente, F de Lope, M Á Jiménez-Clavero, E Frontera.
      We explore the presence of zoonotic flaviviruses (West Nile virus (WNV) and Usutu virus (USUV)) neutralizing antibodies in rarely studied passerine bird species. We report, for the first time in Europe, WNV-specific antibodies in red avadavat and cetti's warbler, and USUV in yellow-crowned bishop. The evidence of WNV and USUV circulating in resident and migratory species has implications for both animal and public health. Future outbreaks in avian reservoir hosts may occur and passerines should be considered as priority target species in flavivirus surveillance programmes.
    Keywords:  Arboviruses; Avian reservoir hosts; Public health; Usutu virus; West Nile virus
    DOI:  https://doi.org/10.1016/j.vetmic.2022.109399
  13. J Family Med Prim Care. 2022 Feb;11(2): 573-580
    Assessment of knowledge and their practices regarding malaria among members of Village Health Sanitation Committee in rural Uttar Pradesh: A cross-sectional study.
    Sandip Kumar, Dhiraj K Srivastava, Kirti Jaiswal, Sushil K Shukla, Prashant K Bajpai, Amit Kaushik.
      Background: In 2019, the global number of malaria cases was estimated at 229 million. An estimated 409,000 deaths were attributed to malaria in 2019. Under-five children are the most susceptible to malaria, accounting for 67% (274,000) of all malaria deaths worldwide in 2019. This study aimed to assess knowledge and practices regarding malaria among Village Health Sanitation Committee (VHSC) members in rural Uttar Pradesh.Methodology: This cross-sectional study was conducted in the villages of four districts of Uttar Pradesh with high malaria burden. In the present study, 484 participants were interviewed from four districts of Uttar Pradesh.
    Results: Nearly all the participants (97.1%) have heard about malaria. Majority of the participants (97.1) were aware that mosquito bites spread malaria. However, many participants were also having a false awareness that malaria is spread by other modes like drinking contaminated water, touching each other, eating contaminated food, and so on. More than half of the participants told that mosquitoes are responsible for malaria breeds in stagnant clean water (25.6%) and stagnant dirty water (28.5%). Nearly half of them were aware that mosquitoes' biting time was sunset (42.1%) and sunrise (7.8%).
    Conclusion: In the present study, many participants were having a false awareness that malaria is spread by other modes like drinking contaminated water, touching each other, eating contaminated food, and so on. Even the knowledge regarding any government program for the prevention and control of malaria of the mosquitoes was very weak. There is an urgent requirement of increasing knowledge among the VHSC members to reduce the malaria burden in the country.
    Keywords:  Knowledge; malaria; practices; rural; transmission
    DOI:  https://doi.org/10.4103/jfmpc.jfmpc_1235_21
This page is being maintained by Thomas Krichel. It was last updated on 2022‒07‒04 at 09:25:14.