bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2022–06–05
eightteen papers selected by
Richard Halfpenny, Staffordshire University
  1. Modifying mosquitoes to suppress disease transmission: Is the long wait over?
  2. Using ecological observations to improve malaria control in areas where Anopheles funestus is the dominant vector.
  3. Prevalence of Knock-Down Resistance F1534S Mutations in Aedes albopictus (Skuse) (Diptera: Culicidae) in North Carolina.
  4. Spatial modelling for population replacement of mosquito vectors at continental scale.
  5. Night Time Extension of Aedes aegypti Human Blood Seeking Activity.
  6. Anopheles stephensi in Africa requires a more integrated response.
  7. Potential future malaria transmission in Odisha due to climate change.
  8. Dengue virus population genetics in Yogyakarta, Indonesia prior to city-wide Wolbachia deployment.
  9. Yellow fever surveillance suggests zoonotic and anthroponotic emergent potential.
  10. The Anopheles lindesayi Species Complex (Diptera: Culicidae) in Bhutan.
  11. Dynamics analysis of stage-structured wild and sterile mosquito interaction impulsive model.
  12. West Nile virus outbreak in Pakistan: Another potential public health threat in the pipeline?
  13. Malaria time series in the extra-Amazon region of Brazil: epidemiological scenario and a two-year prediction model.
  14. Australian floods lead to spread of mosquito-borne disease.
  15. Impact of climate change on West Nile virus distribution in South America.
  16. A Retrospective Analysis of Malaria Trends in Maksegnit Health Center over the Last Seven Years, Northwest Ethiopia: 2014-2020.
  17. Revision of the Educator Group of Culex (Melanoconion) (Diptera, Culicidae).
  18. Creating interventions to transition long-lasting insecticide net distribution in Ghana.
  1. Genetics. 2022 Jun 02. pii: iyac072. [Epub ahead of print]
    Modifying mosquitoes to suppress disease transmission: Is the long wait over?
    Jeffrey R Powell.
      For more than 50 years it has been a dream of medical entomologists and public health workers to control diseases like malaria and dengue fever by modifying, through genetics and other methods, the arthropods that transmit them to humans. A brief synopsis of the history of these efforts as applied to mosquitoes is presented; none proved to be effective in reducing disease prevalence. Only in the last few years have novel approaches been developed or proposed that indicate the long wait may be over. Three recent developments are particularly promising: CRISPR-Cas9 driven genetic modification, shifting naturally occurring allele frequencies, and microbe-based modifications. The last is the furthest along in implementation. Dengue fever incidence has been reduced between 40% and 96% in 4 different regions of the world where Wolbachia-infected Aedes aegypti have been established in the field. It is not yet clear how sustainable such control programs will prove to be, but there is good reason for optimism. In light of this, the time is ripe for reinvigorated research on vectors, especially genetics. Vector-borne diseases primarily affect under-developed countries and thus have not received the attention they deserve from wealthier countries with well-developed and funded biomedical research establishments.
    Keywords:   Aedes aegypti ; Anopheles; GM mosquitoes; Wolbachia; genetic control; selective breeding; transgenic mosquitoes; vector genetics; vector-borne diseases
    DOI:  https://doi.org/10.1093/genetics/iyac072
  2. Malar J. 2022 Jun 02. 21(1): 158
    Using ecological observations to improve malaria control in areas where Anopheles funestus is the dominant vector.
    Najat F Kahamba, Marceline Finda, Halfan S Ngowo, Betwel J Msugupakulya, Francesco Baldini, Lizette L Koekemoer, Heather M Ferguson, Fredros O Okumu.
      The most important malaria vectors in sub-Saharan Africa are Anopheles gambiae, Anopheles arabiensis, Anopheles funestus, and Anopheles coluzzii. Of these, An. funestus presently dominates in many settings in east and southern Africa. While research on this vector species has been impeded by difficulties in creating laboratory colonies, available evidence suggests it has certain ecological vulnerabilities that could be strategically exploited to greatly reduce malaria transmission in areas where it dominates. This paper examines the major life-history traits of An. funestus, its aquatic and adult ecologies, and its responsiveness to key interventions. It then outlines a plausible strategy for reducing malaria transmission by the vector and sustaining the gains over the medium to long term. To illustrate the propositions, the article uses data from south-eastern Tanzania where An. funestus mediates over 85% of malaria transmission events and is highly resistant to key public health insecticides, notably pyrethroids. Both male and female An. funestus rest indoors and the females frequently feed on humans indoors, although moderate to high degrees of zoophagy can occur in areas with large livestock populations. There are also a few reports of outdoor-biting by the species, highlighting a broader range of behavioural phenotypes that can be considered when designing new interventions to improve vector control. In comparison to other African malaria vectors, An. funestus distinctively prefers permanent and semi-permanent aquatic habitats, including river streams, ponds, swamps, and spring-fed pools. The species is therefore well-adapted to sustain its populations even during dry months and can support year-round malaria transmission. These ecological features suggest that highly effective control of An. funestus could be achieved primarily through strategic combinations of species-targeted larval source management and high quality insecticide-based methods targeting adult mosquitoes in shelters. If done consistently, such an integrated strategy has the potential to drastically reduce local populations of An. funestus and significantly reduce malaria transmission in areas where this vector species dominates. To sustain the gains, the programmes should be complemented with gradual environmental improvements such as house modification to maintain biting exposure at a bare minimum, as well as continuous engagements of the resident communities and other stakeholders.
    Keywords:  IRS; ITNs; Ifakara; Larval source management; Malaria transmission; Vector ecology
    DOI:  https://doi.org/10.1186/s12936-022-04198-3
  3. J Med Entomol. 2022 May 29. pii: tjac054. [Epub ahead of print]
    Prevalence of Knock-Down Resistance F1534S Mutations in Aedes albopictus (Skuse) (Diptera: Culicidae) in North Carolina.
    Haley A Abernathy, Brandon D Hollingsworth, Dana A Giandomenico, Kara A Moser, Jonathan J Juliano, Natalie M Bowman, Phillip J George, Michael H Reiskind, Ross M Boyce.
      Knock-down resistance (kdr) mutations in the voltage-gated sodium channel gene of Aedes species mosquitoes are biomarkers for resistance to pyrethroid insecticides. In the United States, few studies have reported kdr mutations among Aedes albopictus (Skuse) (Diptera: Culicidae) populations. In this study, we sought to compare the presence of kdr alleles among Ae. albopictus mosquitoes collected from Fort Bragg and Wake County, North Carolina. We collected 538 Ae. albopictus mosquitoes, including 156 from 4 sites at Fort Bragg, North Carolina and 382 from 15 sites in Wake County, North Carolina to compare the prevalence of kdr mutations. Of those successfully sequenced, we identified 12 (3.0%) mosquitoes with kdr mutations, all of which were attributed to variants at position 1534 within domain 3. All mutations were found in mosquitoes collected at Wake County sites; no mutations were identified in collections from Fort Bragg. There was a focus of mutations observed at the Wake County sites with approximately 92% (11 of 12) of the mosquitoes with the mutation coming from one site, where kdr mutations represented 24.4% (11 of 45) of all mosquitoes collected. We observed highly focal resistance in a suburban area of Raleigh, which may be attributable to peri-domestic mosquito control activities that involve area dispersal of pyrethroid insecticides. More robust surveillance is needed to monitor the emergence and spread of resistance.
    Keywords:   Aedes ; insecticide resistance; mosquito; permethrin; pyrethroid
    DOI:  https://doi.org/10.1093/jme/tjac054
  4. PLoS Comput Biol. 2022 Jun 01. 18(6): e1009526
    Spatial modelling for population replacement of mosquito vectors at continental scale.
    Nicholas J Beeton, Andrew Wilkins, Adrien Ickowicz, Keith R Hayes, Geoffrey R Hosack.
      Malaria is one of the deadliest vector-borne diseases in the world. Researchers are developing new genetic and conventional vector control strategies to attempt to limit its burden. Novel control strategies require detailed safety assessment to ensure responsible and successful deployments. Anopheles gambiae sensu stricto (s.s.) and Anopheles coluzzii, two closely related subspecies within the species complex Anopheles gambiae sensu lato (s.l.), are among the dominant malaria vectors in sub-Saharan Africa. These two subspecies readily hybridise and compete in the wild and are also known to have distinct niches, each with spatially and temporally varying carrying capacities driven by precipitation and land use factors. We model the spread and persistence of a population-modifying gene drive system in these subspecies across sub-Saharan Africa by simulating introductions of genetically modified mosquitoes across the African mainland and its offshore islands. We explore transmission of the gene drive between the two subspecies that arise from different hybridisation mechanisms, the effects of both local dispersal and potential wind-aided migration to the spread, and the development of resistance to the gene drive. Given the best current available knowledge on the subspecies' life histories, we find that an introduced gene drive system with typical characteristics can plausibly spread from even distant offshore islands to the African mainland with the aid of wind-driven migration, with resistance beginning to take over within a decade. Our model accounts for regional to continental scale mechanisms, and demonstrates a range of realistic dynamics including the effect of prevailing wind on spread and spatio-temporally varying carrying capacities for subspecies. As a result, it is well-placed to answer future questions relating to mosquito gene drives as important life history parameters become better understood.
    DOI:  https://doi.org/10.1371/journal.pcbi.1009526
  5. Am J Trop Med Hyg. 2022 May 31. pii: tpmd210309. [Epub ahead of print]
    Night Time Extension of Aedes aegypti Human Blood Seeking Activity.
    Bryson Alberto Ndenga, Francis Maluki Mutuku, Harun Njenga Ngugi, Joel Omari Mbakaya, Dunstan Mukoko, Uriel Kitron, Angelle Desiree LaBeaud.
      This study examined whether Aedes aegypti extends its human blood seeking activity into night hours. Human landing catches (HLC) were conducted hourly from early morning (04:30) to late evening (21:30) in urban and rural sites in Kisumu County in western Kenya, and in Kwale County at the coast. Out of 842 female Ae. aegypti mosquitoes, 71 (8.5%) were collected at night (nocturnal), 151 (17.9%) at twilight (crepuscular), and 620 (73.6%) during the day (diurnal). Three-fold and significantly more Ae. aegypti female mosquitoes were collected during the twilight (crepuscular) hours than night (nocturnal) hours. Significantly more Ae. aegypti female mosquitoes were collected during daytime (diurnal) than night time (nocturnal). In general, the number of mosquitoes collected reduced as darkness increased. Extended time into the night to seek for blood meals enhances chances for Ae. aegypti to contact humans and transmit arboviruses diseases.
    DOI:  https://doi.org/10.4269/ajtmh.21-0309
  6. Malar J. 2022 May 31. 21(1): 156
    Anopheles stephensi in Africa requires a more integrated response.
    Abraham Mnzava, April C Monroe, Fredros Okumu.
      There are increasing reports of the Asian malaria mosquito, Anopheles stephensi invading and spreading in Eastern Africa. We discuss the importance of these invasions in the context of broader challenges facing malaria control in Africa and argue against addressing it as an isolated problem. Anopheles stephensi is only one of multiple biological threats facing malaria control in the region-and is itself an indication of wide-ranging weaknesses in vector surveillance and control programs. Expanded investigations are needed in both urban and rural areas, especially in countries serviced by the Indian Ocean trade routes, to establish the full extent and future trajectories of the problem. More importantly, instead of tackling this vector species as a stand-alone threat, affected countries should adopt more integrated and multi-sectorial initiatives that can sustainably drive and keep out malaria.
    Keywords:  Anopheles stephensi; Biological threats; Horn of Africa; Integrated vector control; Malaria; Vector surveillance
    DOI:  https://doi.org/10.1186/s12936-022-04197-4
  7. Sci Rep. 2022 May 31. 12(1): 9048
    Potential future malaria transmission in Odisha due to climate change.
    Ruchi Singh Parihar, Prasanta Kumar Bal, Atul Saini, Saroj Kanta Mishra, Ashish Thapliyal.
      Future projections of malaria transmission is made for Odisha, a highly endemic region of India, through numerical simulations using the VECTRI dynamical model. The model is forced with bias-corrected temperature and rainfall from a global climate model (CCSM4) for the baseline period 1975-2005 and for the projection periods 2020s, 2050s, and 2080s under RCP8.5 emission scenario. The temperature, rainfall, mosquito density and entomological inoculation rate (EIR), generated from the VECTRI model are evaluated with the observation and analyzed further to estimate the future malaria transmission over Odisha on a spatio-temporal scale owing to climate change. Our results reveal that the malaria transmission in Odisha as a whole during summer and winter monsoon seasons may decrease in future due to the climate change except in few districts with the high elevations and dense forest regions such as Kandhamal, Koraput, Raygada and Mayurbhanj districts where an increase in malaria transmission is found. Compared to the baseline period, mosquito density shows decrease in most districts of the south, southwest, central, north and northwest regions of Odisha in 2030s, 2050s and 2080s. An overall decrease in malaria transmission of 20-40% (reduction in EIR) is seen during the monsoon season (June-Sept) over Odisha with the increased surface temperature of 3.5-4 °C and with the increased rainfall of 20-35% by the end of the century with respect to the baseline period. Furthermore, malaria transmission is likely to reduce in future over most of the Odisha regions with the increase in future warm and cold nights temperatures.
    DOI:  https://doi.org/10.1038/s41598-022-13166-5
  8. Infect Genet Evol. 2022 May 26. pii: S1567-1348(22)00105-8. [Epub ahead of print] 105308
    Dengue virus population genetics in Yogyakarta, Indonesia prior to city-wide Wolbachia deployment.
    Eggi Arguni, Citra Indriani, Ayu Rahayu, Endah Supriyati, Benediktus Yohan, Rahma F Hayati, Satrio Wardana, Warsito Tantowijoyo, Muhammad Ridwan Anshari, Endang Rahayu, Rubangi, Riris Andono Ahmad, Adi Utarini, Cameron P Simmons, R Tedjo Sasmono.
      Dengue has been endemic in Yogyakarta, Indonesia for decades. Here, we report the dengue epidemiology, entomology, and virology in Yogyakarta in 2016-2017, prior to the commencement of the Applying Wolbachia to Eliminate Dengue (AWED) randomized trial. Dengue epidemiological data were compiled and blood samples from dengue-suspected patients were tested for dengue virus (DENV). Ae. aegypti mosquito samples were caught from the field using BG-Sentinel traps and tested for the presence of DENV infection. Sequencing of the DENV E gene was used to determine the phylogeny and genotypes of circulating DENV. Within the last decade, the 2016-2017 dengue incidence was considered very high. Among the 649 plasma samples collected between March 2016-February 2017; and 36,910 mosquito samples collected between December 2016-May 2017, a total of 197 and 38 samples were DENV-positive by qRT-PCR, respectively. All four DENV serotypes were detected, with DENV-3 (n = 88; 44.67%) and DENV-1 (n = 87; 44.16%) as the predominant serotype, followed by DENV-4 (n = 12; 6.09%) and DENV-2 (n = 10; 5.08%). The Yogyakarta DENV-1 isolates were classified into Genotype I and IV, while DENV-2, DENV-3, and DENV-4 isolates were classified into the Cosmopolitan genotype, Genotype I, and Genotype II, respectively. Yogyakarta DENV isolates were closely related to Indonesian strains from neighboring Javanese cities, consistent with the endemic circulation of DENV on this highly populous island. Our study provides comprehensive baseline information on the DENV population genetic characteristics in Yogyakarta, which are useful as baseline data for the AWED trial and the future DENV surveillance in the city in the presence of a Wolbachia-infected Ae. aegypti population.
    Keywords:  Dengue; Epidemiology; Genotype; Phylogeny; Serotype; Wolbachia; Yogyakarta
    DOI:  https://doi.org/10.1016/j.meegid.2022.105308
  9. Commun Biol. 2022 Jun 02. 5(1): 530
    Yellow fever surveillance suggests zoonotic and anthroponotic emergent potential.
    Alisa Aliaga-Samanez, Raimundo Real, Marina Segura, Carlos Marfil-Daza, Jesús Olivero.
      Yellow fever is transmitted by mosquitoes among human and non-human primates. In the last decades, infections are occurring in areas that had been free from yellow fever for decades, probably as a consequence of the rapid spread of mosquito vectors, and of the virus evolutionary dynamic in which non-human primates are involved. This research is a pathogeographic assessment of where enzootic cycles, based on primate assemblages, could be amplifying the risk of yellow fever infections, in the context of spatial changes shown by the disease since the late 20th century. In South America, the most relevant spread of disease cases affects parts of the Amazon basin and a wide area of southern Brazil, where forest fragmentation could be activating enzootic cycles next to urban areas. In Africa, yellow fever transmission is apparently spreading from the west of the continent, and primates could be contributing to this in savannas around rainforests. Our results are useful for identifying new areas that should be prioritised for vaccination, and suggest the need of deep yellow fever surveillance in primates of South America and Africa.
    DOI:  https://doi.org/10.1038/s42003-022-03492-9
  10. J Med Entomol. 2022 Jun 01. pii: tjac052. [Epub ahead of print]
    The Anopheles lindesayi Species Complex (Diptera: Culicidae) in Bhutan.
    Pradya Somboon, Thanari Phanitchakun, Rinzin Namgay, Ralph E Harbach.
      This paper deals with species A, C, D, and E of the Lindesayi Complex of Anopheles subgenus Anopheles (Diptera: Culicidae) that were recently recorded from Bhutan. Species B is not included due to insufficient data. Species A is Anopheles lindesayi sensu stricto, and species C, D, and E are new species that are formally described and named herein as Anopheles druki Somboon, Namgay & Harbach, Anopheles himalayensis Somboon, Namgay & Harbach and Anopheles thimphuensis Somboon, Namgay & Harbach, respectively. Morphological characteristics of the adults, larval and pupal stages of each species are provided and compared with An. lindesayi from Bhutan.
    Keywords:   druki ; himalayensis ; thimphuensis ; new species; taxonomy
    DOI:  https://doi.org/10.1093/jme/tjac052
  11. J Biol Dyn. 2022 Dec;16(1): 464-479
    Dynamics analysis of stage-structured wild and sterile mosquito interaction impulsive model.
    Yiyou Pang, Shuai Wang, Siyu Liu.
      In this paper, we study a stage-structured wild and sterile mosquito interaction impulsive model. The aim is to study the feasibility of controlling the population of wild mosquitoes by releasing sterile mosquitoes periodically. The existence of trivial periodic solutions is obtained, and the corresponding local stability and global stability conditions are proved by Floquet theory and Lyapunov stability theorem, respectively. And we prove the existence conditions of non-trivial periodic solutions and their local stability. We can find that the system has the bistable phenomenon in which the trivial periodic solution and the non-trivial periodic solution can coexist under certain threshold conditions. All the results show that the appropriate release period and release amount of sterile mosquitoes can control the wild mosquito population within a certain range and even make them extinct. Finally, numerical simulation verifies our theoretical results.
    Keywords:  Stage-structure; bifurcation; bistability; impulsive model; periodic solutions
    DOI:  https://doi.org/10.1080/17513758.2022.2079739
  12. Ann Med Surg (Lond). 2022 May;77 103663
    West Nile virus outbreak in Pakistan: Another potential public health threat in the pipeline?
    Summaiyya Waseem, Taha Gul Shaikh, Syed Hassan Ahmed, Rana Muhammad Usama, Muhammad Sohaib Asghar, Muhammad Junaid Tahir.
      West Nile virus (WNV), a single-stranded RNA virus belonging to the family of Flaviviridae, is an arbovirus transmitted to humans predominantly by mosquito bites. It exhibits a wide range of clinical findings ranging from asymptomatic presentation to severe several neurological disorders. WNV has afflicted several countries around the globe including Pakistan. News of yet another outbreak in the country by WNV is circulating again. Concerned authorities should act vigilantly before the endemic takes over completely and bring down the already bereaving healthcare of Pakistan.
    Keywords:  Arbovirus; Epidemic; Global health; Infection; Virus; West Nile fever
    DOI:  https://doi.org/10.1016/j.amsu.2022.103663
  13. Malar J. 2022 May 31. 21(1): 157
    Malaria time series in the extra-Amazon region of Brazil: epidemiological scenario and a two-year prediction model.
    Klauss Kleydmann Sabino Garcia, Amanda Amaral Abrahão, Ana Flávia de Morais Oliveira, Karina Medeiros de Deus Henriques, Anielle de Pina-Costa, André Machado Siqueira, Walter Massa Ramalho.
       BACKGROUND: In Brazil, malaria is caused mainly by the Plasmodium vivax and Plasmodium falciparum species. Its transmission occurs in endemic and non-endemic areas. Malaria geography in Brazil has retracted and is now concentrated in the North region. The Brazilian Amazon region accounts for 99% of Brazil's cases. Brazil's extra-Amazon region has a high frequency of imported cases and in 2019 presented a mortality rate 123 times higher than the Amazon region. Extra-Amazon cases present risks of reintroduction. This study aims to characterize the epidemiological scenario for malaria in the extra-Amazon region of Brazil from 2011 to 2020 with a two-year forecast.
    METHODS: Time-series study with description of malaria cases and deaths registered in Brazilian extra-Amazon region from 2011 to 2020. Public data from the Notifiable Diseases Information System (Sinan) and the Mortality Information System (SIM) were used. Descriptive analysis, incidence, and notification rates were calculated. Flow charts analysed the flux between Places of Probable Infection (PI) and places of notification. The prediction model utilized a multiplicative Holt-winters model for trend and seasonality components.
    RESULTS: A total of 6849 cases were registered. Cases were predominantly white males with 9 to 11 years of education, mostly between 30 and 39 years old. Imported cases accounted for 78.9% of cases. Most frequent occupations for imported cases are related to travelling and tourism activities. Among autochthonous cases, there is a higher frequency of agriculture and domestic economic activities. In the period there were 118 deaths due to malaria, of which 34.7% were caused by P. falciparum infections and 48.3% were not specified. The most intense flows of imported cases are from Amazonas and Rondônia to São Paulo, Rio de Janeiro, and Paraná. The prediction estimates around 611 cases for each of the following two years.
    CONCLUSION: The time series allows a vast epidemiological visualization with a short-term prediction analysis that supports public health planning. Government actions need to be better directed in the extra-Amazon region so the objective of eliminating malaria in Brazil is achieved. Carrying out quality assessments for information systems and qualifying personnel is advisable. Malaria outside the Amazon region is mainly due to imported cases and delay in diagnosis is associated with a higher fatality rate. Better strategies to diagnose and treat suspected cases can lead to lower risk of deaths and local outbreaks that will be important for achieving malaria elimination in Brazil.
    Keywords:  Control; Elimination; Epidemiology; Extra-Amazon; Malaria; Malaria Case; Public Health
    DOI:  https://doi.org/10.1186/s12936-022-04162-1
  14. Lancet Infect Dis. 2022 Jun;pii: S1473-3099(22)00301-2. [Epub ahead of print]22(6): 771
    Australian floods lead to spread of mosquito-borne disease.
    Bianca Nogrady.
      
    DOI:  https://doi.org/10.1016/S1473-3099(22)00301-2
  15. Trans R Soc Trop Med Hyg. 2022 May 27. pii: trac044. [Epub ahead of print]
    Impact of climate change on West Nile virus distribution in South America.
    Camila Lorenz, Thiago Salomão de Azevedo, Francisco Chiaravalloti-Neto.
       BACKGROUND: West Nile virus (WNV) is a vector-borne pathogen of global relevance and is currently the most widely distributed flavivirus causing encephalitis worldwide. Climate conditions have direct and indirect impacts on vector abundance and virus dynamics within the mosquito. The significance of environmental variables as drivers in WNV epidemiology is increasing under the current climate change scenario. In this study we used a machine learning algorithm to model WNV distributions in South America.
    METHODS: Our model evaluated eight environmental variables for their contribution to the occurrence of WNV since its introduction in South America in 2004.
    RESULTS: Our results showed that environmental variables can directly alter the occurrence of WNV, with lower precipitation and higher temperatures associated with increased virus incidence. High-risk areas may be modified in the coming years, becoming more evident with high greenhouse gas emission levels. Countries such as Bolivia, Paraguay and several Brazilian areas, mainly in the northeast and midwest regions and the Pantanal biome, will be greatly affected, drastically changing the current WNV distribution.
    CONCLUSIONS: Understanding the linkages between climatological and ecological change as determinants of disease emergence and redistribution will help optimize preventive strategies. Increased virus surveillance, integrated modelling and the use of geographically based data systems will provide more anticipatory measures by the scientific community.
    Keywords:  South America; West Nile virus; climate change; epidemiology; temperature
    DOI:  https://doi.org/10.1093/trstmh/trac044
  16. J Parasitol Res. 2022 ;2022 5170550
    A Retrospective Analysis of Malaria Trends in Maksegnit Health Center over the Last Seven Years, Northwest Ethiopia: 2014-2020.
    Tegegne Eshetu, Bedruzeman Muhamed, Merima Awol, Zebie Kassa, Mehabaw Getu, Adane Derso, Aberham Abere, Ayalew Jejaw Zeleke.
       Background: In Ethiopia, despite various public health intervention approaches have been implemented to eliminate malaria, its public health problem remains considerable. There are such numerous studies; however, investigating the trend of malaria infection in various settings is paramount for area-specific evidence-based interventions, evaluating ongoing malaria control programs. Hence, since the trend of malaria infection in Maksegnit has not yet been documented, this study is aimed at assessing the seven-year trend of malaria in Maksegnit Health Center.
    Methods: An institutional-based retrospective study was conducted to assess the trend of malaria prevalence over the last seven years (2014-2020) using recorded blood smear reports in the laboratory logbook in Maksegnit Health Center, Northwest Ethiopia.
    Result: Over the last seven years, a total of 28217 clinically malaria-suspected individuals were requested for blood film examination at Maksegnit Health Center. Of whom, microscopically confirmed malaria case was found in 4641/28217 (16.4%). A significant seasonal and interannual variation of malaria cases was observed (P < 0.001). The highest prevalence was observed in years 2014 (25.5%) and 2020 (25.1%), while the minimum annual prevalence was seen in 2017/18 (6.4%). The month of October (25.5%) had the highest number of malaria cases documented, while February had the least (4.7%). Males and individuals under the age group of 15-45 were the most affected segments of the population. A significant interannual fluctuating prevalence of malaria cases was recorded ranging from 25.5% to 6.4% (P < 0.001).
    Conclusion: Malaria is still a public health threat in the study area despite significant fluctuating patterns of malaria was observed in the last seven years. In particular, a bounced back trend of malaria from 2018 to 2020 is alarming. Thus, the implementation of ongoing intervention approaches should be reconsidered, and uninterrupted efforts of the concerned bodies are still needed.
    DOI:  https://doi.org/10.1155/2022/5170550
  17. J Med Entomol. 2022 Jun 01. pii: tjac051. [Epub ahead of print]
    Revision of the Educator Group of Culex (Melanoconion) (Diptera, Culicidae).
    Ivy Luizi Rodrigues de Sá, Rosa Sá Gomes Hutchings, Roger William Hutchings, Maria Anice Mureb Sallum.
      The Educator Group of the Melanoconion Section of Culex (Melanoconion) (Diptera, Culicidae) is reviewed. Currently, the group includes the following valid species: Culex (Melanoconion) aphyllus  Talaga, 2020, Culex (Melanoconion) cristovaoi Duret, 1968, Culex (Melanoconion) educator  Dyar & Knab, 1906, Culex (Melanoconion) eknomios  Forattini & Sallum, 1992, Culex (Melanoconion) inadmirabilis  Dyar, 1928, Culex (Melanoconion) rachoui Duret, 1968, Culex (Melanoconion) theobaldi (Lutz), 1904, Culex (Melanoconion) vaxus  Dyar, 1920, Culex (Melanoconion) angularis Sá & Sallum n. sp., Culex (Melanoconion) spiniformis Sá & Hutchings n. sp., Culex (Melanoconion) longistriatus Sá & Hutchings n. sp., Culex (Melanoconion) aneles  Dyar & Ludlow, 1922, Culex (Melanoconion) apeteticus Howard, Dyar & Ludlow, 1913, and Culex (Melanoconion) bibulus  Dyar, 1920. The last three species were resurrected from synonymy of either Cx. educator or Cx. vaxus. Descriptions, differential diagnoses, bionomics, and geographical data are provided for each species when available.
    Keywords:  Culicini; identification key; new species; taxonomy
    DOI:  https://doi.org/10.1093/jme/tjac051
  18. BMJ Open. 2022 Jun 01. 12(6): e063121
    Creating interventions to transition long-lasting insecticide net distribution in Ghana.
    Franklin Glozah, Emmanuel Asampong, Philip Teg-Nefaah Tabong, Adanna Nwameme, Ruby Hornuvo, Margaret Chandi, Nana Yaw Peprah, Philip Adongo, Phyllis Dako-Gyeke.
       OBJECTIVE: Mass long-lasting insecticide net (LLIN) distribution campaigns are rolled out, as a part of the Ghana Malaria Strategic plan (2021-2025) which seeks to protect at least 80% of the population at risk with effective malaria prevention interventions. Although the mass LLIN distribution campaign indicates a comprehensive stakeholder engagement approach, it does not systematically transition into the basic primary healthcare structures within the Ghana Health Services. This paper presents the process and outcome of creating an innovative social intervention, which focuses on community mobilisation and capacity building of community health officers.
    METHODS: This study employed a concurrent triangulation mixed methods approach conducted across six districts in Eastern and Volta regions, Ghana. Findings were synthesised, grouped and further distilled to guide the participatory cocreation workshops. Cocreation involved participatory learning in action technique which is a practical, adaptive research strategy which enabled diverse groups and individuals to learn, work and act together in a cooperative manner.
    RESULTS: The results suggest the establishment of a Community Health Advocacy Team (CHAT). This would be necessary in efforts aimed at transitioning LLIN distribution campaign in communities. The role of the CHAT would be centred on key elements of community/social mobilisation and capacity building, all nested in a social and behaviour change communication strategies.
    CONCLUSION: The research team is in the process of assessing the acceptability and feasibility of the CHAT intervention with all stakeholders in the various communities. Assessment of the effectiveness of the CHAT intervention would be done at a later time.
    Keywords:  health policy; public health; social medicine; tropical medicine
    DOI:  https://doi.org/10.1136/bmjopen-2022-063121
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