bims-mosdis 2022-06-19 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–06–19
sixteen papers selected by
Richard Halfpenny, Staffordshire University

Entomological indicators of malaria transmission prior to a cluster-randomized controlled trial of a 'lethal house lure' intervention in central Côte d'Ivoire.
Disruption of spatiotemporal clustering in dengue cases by wMel Wolbachia in Yogyakarta, Indonesia.
From a long-distance threat to the invasion front: a review of the invasive Aedes mosquito species in Belgium between 2007 and 2020.
Mosquito Diversity in an Experimental Township in Tamil Nadu, India.
Morphological and molecular characterization of Aedes aegypti variant collected from Tamil Nadu, India.
Incremental cost and cost-effectiveness of the addition of indoor residual spraying with pirimiphos-methyl in sub-Saharan Africa versus standard malaria control: results of data collection and analysis in the Next Generation Indoor Residual Sprays (NgenIRS) project, an economic-evaluation.
Dengue virus transovarial transmission detection in Aedes aegypti from dengue hemorrhagic fever patients' residences in Denpasar, Bali.
Diversity of larval habitats of Anopheles mosquitoes in urban areas of Benin and influence of their physicochemical and bacteriological characteristics on larval density.
Molecular Detection of Plasmodium Infection among Anophelinae Mosquitoes and Differentiation of Biological Forms of Anopheles Stephensi Collected from Malarious Areas of Afghanistan and Iran.
Malaria mosquitoes acquire and allocate cattle urine to enhance life history traits.
First national record of Aedes melanimon (Diptera: Culicidae) in Mexico.
Complete mitochondrial genome of a malaria vector mosquito Anopheles sinensis from South Korea.
Malaria Threatens to Bounce Back in Abergele District, Northeast Ethiopia: Five-Year Retrospective Trend Analysis from 2016-2020 in Nirak Health Center.
Risk factors for infection with chikungunya and Zika viruses in southern Puerto Rico: A community-based cross-sectional seroprevalence survey.
High asymptomatic malaria among seasonal migrant workers departing to home from malaria endemic areas in northwest Ethiopia.
Socioeconomic disparities associated with symptomatic Zika virus infections in pregnancy and congenital microcephaly: A spatiotemporal analysis from Goiânia, Brazil (2016 to 2020).

Malar J. 2022 Jun 15. 21(1): 188

Entomological indicators of malaria transmission prior to a cluster-randomized controlled trial of a 'lethal house lure' intervention in central Côte d'Ivoire.

Rosine Z Wolie, Alphonsine A Koffi, Leslie Ayuk-Taylor, Ludovic P Ahoua Alou, Eleanore D Sternberg, Oulo N'Nan-Alla, Yao N'Guessan, Amal Dahounto, Welbeck A Oumbouke, Innocent Z Tia, Simon-Pierre A N'Guetta, Jackie Cook, Matthew B Thomas, Raphael N'Guessan.

   BACKGROUND: A study was conducted prior to implementing a cluster-randomized controlled trial (CRT) of a lethal house lure strategy in central Côte d'Ivoire to provide baseline information on malaria indicators in 40 villages across five health districts.
METHODS: Human landing catches (HLC) were performed between November and December 2016, capturing mosquitoes indoors and outdoors between 18.00 and 08.00 h. Mosquitoes were processed for entomological indicators of malaria transmission (human biting, parity, sporozoite, and entomological inoculation rates (EIR)). Species composition and allelic frequencies of kdr-w and ace-1R mutations were also investigated within the Anopheles gambiae complex.
RESULTS: Overall, 15,632 mosquitoes were captured. Anopheles gambiae sensu lato (s.l.) and Anopheles funestus were the two malaria vectors found during the survey period, with predominance for An. gambiae (66.2%) compared to An. funestus (10.3%). The mean biting rate for An. gambiae was almost five times higher than that for An. funestus (19.8 bites per person per night for An. gambiae vs 4.3 bites per person per night for An. funestus) and this was evident indoors and outdoors. Anopheles funestus was more competent to transmit malaria parasites in the study area, despite relatively lower number tested for sporozoite index (4.14% (63/1521) for An. gambiae vs 8.01% (59/736) for An. funestus; χ2 = 12.216; P < 0.0001). There were no significant differences between the proportions infected outdoors and indoors for An. gambiae (4.03 vs 4.13%; χ2 = 0.011; P = 0.9197) and for An. funestus (7.89 vs 8.16%; χ2 = 2.58e-29; P = 1). The majority of both infected vectors with malaria parasites harboured Plasmodium falciparum (93.65% for An. gambiae and 98. 31% for An. funestus). Overall, the EIR range for both species in the different districts appeared to be high (0.35-2.20 infected bites per human per night) with the highest value observed in the district of North-Eastern-Bouaké. There were no significant differences between transmission occurring outdoor and indoor for both species. Of the An. gambiae s.l. analysed, only An. gambiae sensu stricto (14.1%) and Anopheles coluzzii (85.9%) were found. The allelic frequencies of kdr and ace-1R were higher in An. gambiae (0.97 for kdr and 0.19 for ace-1R) than in An. coluzzii (0.86 for kdr and 0.10 for ace-1R) (P < 0.001).
CONCLUSION: Despite universal coverage with long-lasting insecticidal nets (LLINs) in the area, there was an abundance of the malaria vectors (An. gambiae and An. funestus) in the study area in central Côte d'Ivoire. Consistent with high insecticide resistance intensity previously detected in these districts, the current study detected high kdr frequency (> 85%), coupled with high malaria transmission pattern, which could guide the use of Eave tubes in the study areas.

Keywords:  Anopheles; Côte d’Ivoire; Insecticide resistance genes; Malaria transmission; Plasmodium

DOI:  https://doi.org/10.1186/s12936-022-04196-5
Sci Rep. 2022 Jun 14. 12(1): 9890

Disruption of spatiotemporal clustering in dengue cases by wMel Wolbachia in Yogyakarta, Indonesia.

Suzanne M Dufault, Stephanie K Tanamas, Citra Indriani, Adi Utarini, Riris Andono Ahmad, Nicholas P Jewell, Cameron P Simmons, Katherine L Anders.

Dengue exhibits focal clustering in households and neighborhoods, driven by local mosquito population dynamics, human population immunity, and fine scale human and mosquito movement. We tested the hypothesis that spatiotemporal clustering of homotypic dengue cases is disrupted by introduction of the arbovirus-blocking bacterium Wolbachia (wMel-strain) into the Aedes aegypti mosquito population. We analysed 318 serotyped and geolocated dengue cases (and 5921 test-negative controls) from a randomized controlled trial in Yogyakarta, Indonesia of wMel deployments. We find evidence of spatial clustering up to 300 m among the 265 dengue cases (3083 controls) in the untreated trial arm. Participant pairs enrolled within 30 days and 50 m had a 4.7-fold increase (compared to 95% CI on permutation-based null distribution: 0.1, 1.2) in the odds of being homotypic (i.e. potentially transmission-related) as compared to pairs occurring at any distance. In contrast, we find no evidence of spatiotemporal clustering among the 53 dengue cases (2838 controls) resident in the wMel-treated arm. Introgression of wMel Wolbachia into Aedes aegypti mosquito populations interrupts focal dengue virus transmission leading to reduced case incidence; the true intervention effect may be greater than the 77% efficacy measured in the primary analysis of the Yogyakarta trial.

DOI: https://doi.org/10.1038/s41598-022-13749-2
Parasit Vectors. 2022 Jun 13. 15(1): 206

From a long-distance threat to the invasion front: a review of the invasive Aedes mosquito species in Belgium between 2007 and 2020.

Isra Deblauwe, Katrien De Wolf, Jacobus De Witte, Anna Schneider, Ingrid Verlé, Adwine Vanslembrouck, Nathalie Smitz, Julie Demeulemeester, Thomas Van Loo, Wouter Dekoninck, Meryam Krit, Maxime Madder, Ruth Müller, Wim Van Bortel.

  Invasive mosquito species (IMS) and their associated mosquito-borne diseases are emerging in Europe. In Belgium, the first detection of Aedes albopictus (Skuse 1894) occurred in 2000 and of Aedes japonicus japonicus (Theobald 1901) in 2002. Early detection and control of these IMS at points of entry (PoEs) are of paramount importance to slow down any possible establishment. This article reviews the introductions and establishments recorded of three IMS in Belgium based on published (2007-2014) and unpublished (2015-2020) data collected during several surveillance projects. In total, 52 PoEs were monitored at least once for the presence of IMS between 2007 and 2020. These included used tyre and lucky bamboo import companies, airports, ports, parking lots along highways, shelters for imported cutting plants, wholesale markets, industrial areas, recycling areas, cemeteries and an allotment garden at the country border with colonised areas. In general, monitoring was performed between April and November. Mosquitoes were captured with adult and oviposition traps as well as by larval sampling. Aedes albopictus was detected at ten PoEs, Ae. japonicus at three PoEs and Aedes koreicus (Edwards 1917) at two PoEs. The latter two species have established overwintering populations. The percentage of PoEs positive for Ae. albopictus increased significantly over years. Aedes albopictus is currently entering Belgium through lucky bamboo and used tyre trade and passive ground transport, while Ae. japonicus through used tyre trade and probably passive ground transport. In Belgium, the import through passive ground transport was first recorded in 2018 and its importance seems to be growing. Belgium is currently at the invasion front of Ae. albopictus and Ae. japonicus. The surveillance and control management actions at well-known PoEs associated to long-distance introductions are more straightforward than at less-defined PoEs associated with short-distance introductions from colonised areas. These latter PoEs represent a new challenge for IMS management in Belgium in the coming years. Aedes albopictus is expected to become established in Belgium in the coming years, hence increasing the likelihood of local arbovirus transmission. The implementation of a sustainable, structured and long-term IMS management programme, integrating active and passive entomological surveillance, vector control and Public Health surveillance is therefore pivotal.

Keywords:  Aedes albopictus; Aedes japonicus japonicus; Aedes koreicus; Culicidae; Establishment; Exotic mosquito species; Introduction pathways; Mosquito monitoring; Point of entry; Surveillance

DOI:  https://doi.org/10.1186/s13071-022-05303-w
J Med Entomol. 2022 Jun 15. pii: tjac064. [Epub ahead of print]

Mosquito Diversity in an Experimental Township in Tamil Nadu, India.

P Visa Shalini, A N Shriram, A Elango, R Natarajan, B Vijayakumar, K H K Raju, Lucas Dengel, K Gunasekaran, Ashwani Kumar.

  To glean more information on mosquito diversity and distribution in Auroville, a cross-sectional study was carried out by mapping the distribution of water bodies and habitats supporting immature stages on the one hand and the distribution of water bodies/habitats supporting mosquito immature stages on the other. A satellite image covering an area of 8.08 km2 was overlaid with a grid of 500 × 500 m. Fifteen modules were selected and the area of each module served as the sampling site for the entomological survey. Adult and larval stages were sampled. Diversity indices were analyzed to compare mosquito diversity. Rarefaction estimations were used to compare abundance and richness of the mosquito species between different zones. In total, 750 mosquito larvae and 84 resting adults were sampled. Eighteen species of mosquitoes belonging to 11 subgenera and 7 genera were documented. Genera included Aedes (Johann Wilhelm Meigen 1818, Diptera, Culicidae), Anopheles (Johann Wilhelm Meigen 1818, Diptera, Culicidae), Armigeres (Theobald 1901, Diptera, Culicidae), Culex (Carl Linnaeus 1758, Diptera, Culicidae), Lutzia (Theobald 1903, Diptera, Culicidae), and Mimomyia (Theobald 1903, Diptera, Culicidae). Of the 18 mosquito species identified, 8 species are new records for Auroville. The Alpha (α) biodiversity indices show that the mosquito fauna is diverse (S = 18; DMg = 2.732 [95% CI: 2.732-2.732]). The Shannon-Weiner (H' = 2.199 [95% CI: 2.133-2.276]) and Simpson indices (λ = 0.8619 [95% CI: 0.8496-0.8723]) measured species richness, evenness, and dominance. The values of these indices suggest high species richness, evenness, and dominance. Prevailing conditions can provide suitable environment for establishment of different mosquito species in this ecosystem. Given the sociodemographic characteristics of this area, research on mosquito diversity and risk of vector-borne diseases will be of great use.

Keywords:  Auroville; Culicidae; India; biodiversity; rarefaction

DOI:  https://doi.org/10.1093/jme/tjac064
J Vector Borne Dis. 2022 Jan-Mar;59(1):59(1): 22-28

Morphological and molecular characterization of Aedes aegypti variant collected from Tamil Nadu, India.

P Nirmal Kumar, M Kalimuthu, M Senthil Kumar, R Govindrajan, A Venkatesh, R Paramasivan, Ashwani Kumar, Bhavna Gupta.

   BACKGROUND & OBJECTIVES: Accurate mosquito species identification is the basis of entomological surveys and effective vector control. Mosquito identification is either done morphologically using diagnostic features mentioned in taxonomic keys or by molecular methods using cytochrome oxidase subunit 1 (coxI) and Internal transcribed spacer 2 (ITS2).
METHODS: We performed a larval survey for Aedes mosquitoes from eight different geographical regions in Tamil Nadu, India. The mosquitoes collected during the survey were characterized using both morphological and molecular markers.
RESULTS: During an entomological survey from eight different geographical regions in Southern India, a morphological variety named Aedes aegypti var. luciensis was observed. The variant mosquitoes were characterized using both morphological and molecular markers. The variant mosquitoes differed only in the dark scaling of 5th segment of hind-tarsi. Around one third to two third of the 5th segment in variant mosquitoes was dark which has been described as white in identification keys. No other significant difference was observed in adults or immature stages. The variation was heritable and coexisting in the field with the type form mosquitoes. Comparison of the genetic profile of coxI and ITS2 were similar in variant and the type form indicating both of them to be conspecific.
INTERPRETATION & CONCLUSION: The morphological variant mosquitoes were found genetically similar to the Ae. aegypti type form. However, considering its high prevalence and coexistence with Ae. aegypti type form in different geographical regions, detailed studies on bionomics, ecology, genetics, behavior as well as its plausible role in disease transmission are warranted.

Keywords:  Aedes aegypti; India; coxI; morphological variant; var. luciensis

DOI:  https://doi.org/10.4103/0972-9062.331413
Malar J. 2022 Jun 11. 21(1): 185

Incremental cost and cost-effectiveness of the addition of indoor residual spraying with pirimiphos-methyl in sub-Saharan Africa versus standard malaria control: results of data collection and analysis in the Next Generation Indoor Residual Sprays (NgenIRS) project, an economic-evaluation.

Joshua Yukich, Peder Digre, Sara Scates, Luc Boydens, Emmanuel Obi, Nicky Moran, Allison Belemvire, Mariandrea Chamorro, Benjamin Johns, Keziah L Malm, Lena Kolyada, Ignatius Williams, Samuel Asiedu, Seydou Fomba, Jules Mihigo, Desire Boko, Baltazar Candrinho, Rodaly Muthoni, Jimmy Opigo, Catherine Maiteki-Sebuguzi, Damian Rutazaana, Josephat Shililu, Asaph Muhanguzi, Kassahun Belay, Joel Kisubi, Joselyn Annet Atuhairwe, Presley Musonda, Nduka Iwuchukwu, John Ngosa, Elizabeth Chizema, Reuben Zulu, Emmanuel Kooma, John Miller, Adam Bennett, Kyra Arnett, Kenzie Tynuv, Christelle Gogue, Joseph Wagman, Jason H Richardson, Laurence Slutsker, Molly Robertson.

   BACKGROUND: Malaria is a major cause of morbidity and mortality globally, especially in sub-Saharan Africa. Widespread resistance to pyrethroids threatens the gains achieved by vector control. To counter resistance to pyrethroids, third-generation indoor residual spraying (3GIRS) products have been developed. This study details the results of a multi-country cost and cost-effectiveness analysis of indoor residual spraying (IRS) programmes using Actellic®300CS, a 3GIRS product with pirimiphos-methyl, in sub-Saharan Africa in 2017 added to standard malaria control interventions including insecticide-treated bed nets versus standard malaria control interventions alone.
METHODS: An economic evaluation of 3GIRS using Actellic®300CS in a broad range of sub-Saharan African settings was conducted using a variety of primary data collection and evidence synthesis methods. Four IRS programmes in Ghana, Mali, Uganda, and Zambia were included in the effectiveness analysis. Cost data come from six IRS programmes: one in each of the four countries where effect was measured plus Mozambique and a separate programme conducted by AngloGold Ashanti Malaria Control in Ghana. Financial and economic costs were quantified and valued. The main indicator for the cost was cost per person targeted. Country-specific case incidence rate ratios (IRRs), estimated by comparing IRS study districts to adjacent non-IRS study districts or facilities, were used to calculate cases averted in each study area. A deterministic analysis and sensitivity analysis were conducted in each of the four countries for which effectiveness evaluations were available. Probabilistic sensitivity analysis was used to generate plausibility bounds around the incremental cost-effectiveness ratio estimates for adding IRS to other standard interventions in each study setting as well as jointly utilizing data on effect and cost across all settings.
RESULTS: Overall, IRRs from each country indicated that adding IRS with Actellic®300CS to the local standard intervention package was protective compared to the standard intervention package alone (IRR 0.67, [95% CI 0.50-0.91]). Results indicate that Actellic®300CS is expected to be a cost-effective (> 60% probability of being cost-effective in all settings) or highly cost-effective intervention across a range of transmission settings in sub-Saharan Africa.
DISCUSSION: Variations in the incremental costs and cost-effectiveness likely result from several sources including: variation in the sprayed wall surfaces and house size relative to household population, the underlying malaria burden in the communities sprayed, the effectiveness of 3GIRS in different settings, and insecticide price. Programmes should be aware that current recommendations to rotate can mean variation and uncertainty in budgets; programmes should consider this in their insecticide-resistance management strategies.
CONCLUSIONS: The optimal combination of 3GIRS delivery with other malaria control interventions will be highly context specific. 3GIRS using Actellic®300CS is expected to deliver acceptable value for money in a broad range of sub-Saharan African malaria transmission settings.

Keywords:  3GIRS; Actellic®300CS; Cost; Cost-effectiveness; IRS; Indoor residual spraying; Malaria; NgenIRS; Pirimiphos-methyl; Vector control

DOI:  https://doi.org/10.1186/s12936-022-04160-3
Vet World. 2022 Apr;15(4): 1149-1153

Dengue virus transovarial transmission detection in Aedes aegypti from dengue hemorrhagic fever patients' residences in Denpasar, Bali.

I Made Sudarmaja, I Kadek Swastika, Luh Putu Eka Diarthini, I Putu Dema Prasetya, I Md Ady Wirawan.

   Background and Aim: To effectively control dengue hemorrhagic fever (DHF), it is necessary to assess the risk of vertical virus transmission in Aedes aegypti mosquitoes. This study aimed to detect dengue virus (DENV) transovarial transmission in A. aegypti collected from DHF patients' residences in Denpasar, Bali.
Materials and Methods: A. aegypti samples were acquired by rearing A. aegypti eggs collected from ovitraps placed in the homes of DHF patients. Ovitraps were installed for 7 days and viewed using a loupe to determine whether there were Aedes spp. eggs present. An immunocytochemical method was utilized with 200 samples, and virus detection was performed using a reverse transcriptase-polymerase chain reaction (RT-PCR).
Results: Of the 10 DHF patient houses fitted with ovitraps, four produced positive ovitraps from which larvae developed (house index=40%). Of the 50 ovitraps mounted in the 10 homes, 14 ovitraps were positive and contained A. aegypti eggs (ovitrap index=28%). Of these 14 positive ovitraps containing A. aegypti eggs, 10 ovitraps produced larvae. Immunocytochemical tests were conducted on A. aegypti eggs from the four houses under study. It was found that from the 200 samples collected, 197 samples could be observed, and 11 samples (5.6%) were positive for DENV antigen. RT-PCR examination conducted on mosquitoes reared from the four houses studied obtained a negative virus content result.
Conclusion: This study found the presence of DENV antigen to be as high as 5.6%. This means that potential for transovarial transmission exists within DHF patients' homes in Denpasar, Bali. Aedes control strategy in Denpasar should address this finding, in addition to the current approaches which have focused primarily on the elimination of larval breeding habitats and control of adults using insecticidal fogging during outbreaks.

Keywords:  Aedes aegypti; dengue virus; immunocytochemical; transovarial transmission

DOI:  https://doi.org/10.14202/vetworld.2022.1149-1153
Parasit Vectors. 2022 Jun 13. 15(1): 207

Diversity of larval habitats of Anopheles mosquitoes in urban areas of Benin and influence of their physicochemical and bacteriological characteristics on larval density.

Donald Hessou-Djossou, Innocent Djègbè, Koffi Mensah Ahadji-Dabla, Odilon M Nonfodji, Geneviève Tchigossou, Rousseau Djouaka, Sylvie Cornelie, Luc Djogbenou, Martin Akogbeto, Fabrice Chandre.

   BACKGROUND: The implementation of anti-larval strategies in the fight against malaria vectors requires fundamental knowledge of their oviposition sites. The aim of this study was to assess the spatial and temporal distribution of Anopheles breeding sites as well as the influence of abiotic and biotic factors on the proliferation of larvae in urban and non-urban areas of Benin.
METHODS: Sampling of Anopheles larvae was carried out during the rainy and dry seasons in urbanized and non-urbanized areas of the cities of Cotonou, Bohicon, Parakou, and Natitingou in Benin. The Anopheles larval breeding sites were georeferenced and characterized by their nature, type, physicochemical (pH, temperature, dissolved oxygen, conductivity, turbidity, salinity) and biological attributes (larval density and coliform density).
RESULTS: A total of 198 positive breeding sites for Anopheles larvae were identified, comprising 163 (82.3%) in the rainy season and 35 (17.7%) in the dry season. Out of these larval habitats, 61.9% were located in urbanized areas, and were predominantly puddles. Principal component analysis revealed a high positive correlation of larval density with temperature and dissolved oxygen, and with salinity in the coastal zone. In addition, cross-sectional analysis of the microbiological results with larval density showed a significant negative correlation between larval productivity and faecal coliform load.
CONCLUSIONS: This study indicated the presence of multiple larval habitats of Anopheles in the urban areas which were created through human activities, and associations between larval density and intrinsic factors of the habitats such as temperature, dissolved oxygen and faecal coliform load. This type of information may be useful for the implementation of appropriate control strategies in urban areas, including regulation of the human activities that lead to the creation of breeding sites, proper environmental management and targeted larvicidal use.

Keywords:  Anopheles; Ecology; Faecal coliforms; Larval density; Physicochemical parameters

DOI:  https://doi.org/10.1186/s13071-022-05323-6
Ethiop J Health Sci. 2022 Mar;32(2): 269-278

Molecular Detection of Plasmodium Infection among Anophelinae Mosquitoes and Differentiation of Biological Forms of Anopheles Stephensi Collected from Malarious Areas of Afghanistan and Iran.

Vahideh Moin-Vaziri, Navid Dinparast Djadid, Helen Hoosh-Deghati, Hoda Atta, Abbas Ali Raz, Seyyed Javad Seyyed-Tabaei, Naseh Maleki-Ravasan, Sedigheh Zakeri.

   Background: Updated information on the vectorial capacity of vectors is required in each malarious areas as well in Iran and its neighboring countries such as Afghanistan. The aims of this study were to investigate the potential infection of about 800 specimens collected from malarious areas of Afghanistan and Iran, and to differentiate biological forms of Anopheles stephensi.
Method: Two molecular markers, 18S RNA gene subunit and AsteObp1 intron I, were used respectively for investigation Plasmodium infection and identifying the biological forms of An. stephensi.
Results: Plasmodium infection was detected in 4 pools of Afghanistan specimens, including An. stephensi, collected from Nangarhar. Individually examination showed infection in 5 An. stephensi (infection rate: 1.25), to P. falciparum (2), P. vivax (2) and a mix infection. Out of five infected specimens, three were intermediate forms and two were mysorensis. No infection was found in specimens collected from Iran (Chabahar County), probably due to the active malaria control program in south-east of Iran.
Conclusion: The key role of An. stephensi, as a known Asian malaria vector, was re-emphasized in Afghanistan by the results achieved here. The fauna of vectors and the pattern of biological forms of An. stephensi are similar in both countries that urge regional investigations to provide evidence-based and applied data for decision-maker in malaria control.

Keywords:  Afghanistan; Anopheles stephensi; Iran; OBP1 gene; Plasmodium spp

DOI:  https://doi.org/10.4314/ejhs.v32i2.7
Malar J. 2022 Jun 11. 21(1): 180

Malaria mosquitoes acquire and allocate cattle urine to enhance life history traits.

Mengistu Dawit, Sharon R Hill, Göran Birgersson, Habte Tekie, Rickard Ignell.

BACKGROUND: Nutrient acquisition and allocation integrate foraging and life-history traits in insects. To compensate for the lack of a particular nutrient at different life stages, insects may acquire these through supplementary feeding, for example, on vertebrate secretions, in a process known as puddling. The mosquito Anopheles arabiensis emerges undernourished, and as such, requires nutrients for both metabolism and reproduction. The purpose of this study was to assess whether An. arabiensis engage in puddling on cattle urine to obtain nutrients to improve life history traits.
METHODS: To determine whether An. arabiensis are attracted to the odour of fresh, 24 h, 72 h and 168 h aged cattle urine, host-seeking and blood-fed (48 h post-blood meal) females were assayed in a Y-tube olfactometer, and gravid females assessed in an oviposition assay. Combined chemical and electrophysiological analyses were subsequently used to identify the bioactive compounds in all four age classes of cattle urine. Synthetic blends of bioactive compounds were evaluated in both Y-tube and field assays. To investigate the cattle urine, and its main nitrogenous compound, urea, as a potential supplementary diet for malaria vectors, feeding parameters and life history traits were measured. The proportion of female mosquitoes and the amount of cattle urine and urea imbibed, were assessed. Following feeding, females were evaluated for survival, tethered flight and reproduction.
RESULTS: Host-seeking and blood-fed An. arabiensis were attracted to the natural and synthetic odour of fresh and aged cattle urine in both laboratory and field studies. Gravid females were indifferent in their response to cattle urine presence at oviposition sites. Host-seeking and blood-fed females actively imbibed cattle urine and urea, and allocated these resources according to life history trade-offs to flight, survival or reproduction, as a function of physiological state.
CONCLUSIONS: Anopheles arabiensis acquire and allocate cattle urine to improve life history traits. Supplementary feeding on cattle urine affects vectorial capacity directly by increasing daily survival and vector density, as well as indirectly by altering flight activity, and thus should be considered in future models.

DOI: https://doi.org/10.1186/s12936-022-04179-6
J Vector Borne Dis. 2022 Jan-Mar;59(1):59(1): 102-104

First national record of Aedes melanimon (Diptera: Culicidae) in Mexico.

M David Mejia-Zuniga, Ángel G Reyes-Moya, Janeth A Tapia-Bueno, Laura J Moncada-Hernandez, Aldo I Ortega-Morales, Miguel Moreno-Garcia, Cassandra González-Acosta, Fabián Correa-Morales.

  Aedes (Ochlerotatus) melanimon Dyar 1924 has been considered an important pest in agricultural and rural communities. Aedes melanimon is a vector of WEEV and CEV and is a competent laboratory vector of WNV. The known range of Ae. melanimon extends throughout Southwest Canada, part of Central and most of Western USA. Here we report the first record of Ae. melanimon in Mexico, at Ciudad Juárez, Chihuahua. The collect represents the southernmost distributional record for this species. Its indigenous presence in a highly urbanized and dry area was not expected. A permanent surveillance program to detect and determine the species in border-crossing cities is encouraged.

Keywords:  Aedes melanimon; Mexico; USA; exotic species; vector-borne diseases

DOI:  https://doi.org/10.4103/0972-9062.331418
Mitochondrial DNA B Resour. 2022 ;7(5): 881-883

Complete mitochondrial genome of a malaria vector mosquito Anopheles sinensis from South Korea.

Ashraf Akintayo Akintola, Bia Park, Eun Hwa Choi, Ui Wook Hwang.

  We present the complete mitochondrial genome of a Malaria vector Mosquito Anopheles sinensis Wiedemann, 1828 from South Korea. The mitochondrial genome is about 15,421 bp long and contains 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an A-T rich region. The present data were compared with those from China with respect to PCG sequence differences, tRNA structure, gene order, and control region (CR) structure. An. sinensis mitochondrial genomes from northeast Asia share identical gene composition and gene order. In contrast, they have distinct differences in the CR within the range 8.75% (51/583 bp) to 9.95% (58/583 bp). The phylogenetic analysis showed that An. sinensis from South Korea was clustered together with those from China, but there existed distinct genetic distance between the two. Likewise, mitochondrial genome sequences from other Anopheles species were employed to infer phylogenetic relationships among the members of the genus Anopheles. This study further promotes the enrichment of An. sinensis mitochondrial genome data, providing useful information for their mitochondrial genetic differences along with geographical distances in northeast Asia.

Keywords:  Anopheles sinensis; South Korea; mitochondrial genome; phylogeny

DOI:  https://doi.org/10.1080/23802359.2022.2077665
Biomed Res Int. 2022 ;2022 6388979

Malaria Threatens to Bounce Back in Abergele District, Northeast Ethiopia: Five-Year Retrospective Trend Analysis from 2016-2020 in Nirak Health Center.

Habtu Debash, Yonas Erkihun, Habtye Bisetegn.

Background: In Sub-Saharan African countries, malaria is a leading cause of morbidity and mortality. In Ethiopia, malaria is found in three-fourths of its land mass with more than 63 million people living in malaria endemic areas. Nowadays, Ethiopia is implementing a malaria elimination program with the goal of eliminating the disease by 2030. To assist this goal, the trends of malaria cases should be evaluated with a function of time in different areas of the country to develop area-specific evidence-based interventions. Therefore, this study was aimed at analysing a five year trend of malaria in Nirak Health Center, Abergele District, Northeast Ethiopia, from 2016 to 2020.
Methods: A retrospective study was conducted at Nirak Health Center, Abergele District, Northeast Ethiopia from February to April 2021. Five-year (2016 to 2020) retrospective data were reviewed from the malaria registration laboratory logbook. The sociodemographic and malaria data were collected using a predesigned data collection sheet. Data were entered, cleaned, and analysed using SPSS version 26.
Results: In the five-year period, a total of 19,433 malaria suspected patients were diagnosed by microscopic examination. Of these, 6,473 (33.3%) were positive for malaria parasites. Of the total confirmed cases, 5,900 (91.2%) were P. falciparum and 474 (7.2%) were P. vivax. Majority of the cases were males (62.2%) and in the age group of 15-45 years old (52.8%). The findings of this study showed an increasing trend in malaria cases in the past five years (2016-2020). The maximum number of confirmed malaria cases reported was in the year 2020, while the minimum number of confirmed malaria cases registered was in 2016. Regarding the seasonal distribution of malaria, the highest number of malaria cases (55.2%) was observed in Dry season (September to January) and also the least (15.9%) was observed in Autumn (March to May) replaced by the least (21.6%) was observed in Rainy season (June to August), that is, the major malaria transmission season in Ethiopia and the least (15.9%) was observed in autumn (March to May).
Conclusion: The trends of malaria in Nirak Health Center showed steadily increasing from the year 2016-2020, and the predominant species isolated was P. falciparum. This showed that the malaria control and elimination strategy in the area were not properly implemented or failed to achieve its designed goal. Therefore, this finding alarms the local governments and other stack holders urgently to revise their intervention strategies and take action in the locality.

DOI: https://doi.org/10.1155/2022/6388979
PLoS Negl Trop Dis. 2022 Jun;16(6): e0010416

Risk factors for infection with chikungunya and Zika viruses in southern Puerto Rico: A community-based cross-sectional seroprevalence survey.

Laura E Adams, Liliana Sánchez-González, Dania M Rodriguez, Kyle Ryff, Chelsea Major, Olga Lorenzi, Mark Delorey, Freddy A Medina, Jorge L Muñoz-Jordán, Grayson Brown, Marianyoly Ortiz, Stephen H Waterman, Vanessa Rivera-Amill, Gabriela Paz-Bailey.

Chikungunya virus (CHIKV) caused a large outbreak in Puerto Rico in 2014, followed by a Zika virus (ZIKV) outbreak in 2016. Communities Organized for the Prevention of Arboviruses (COPA) is a cohort study in southern Puerto Rico, initiated in 2018 to measure arboviral disease risk and provide a platform to evaluate interventions. To identify risk factors for infection, we assessed prevalence of previous CHIKV infection and recent ZIKV and DENV infection in a cross-sectional study among COPA participants. Participants aged 1-50 years (y) were recruited from randomly selected households in study clusters. Each participant completed an interview and provided a blood specimen, which was tested by anti-CHIKV IgG ELISA assay and anti-ZIKV and anti-DENV IgM MAC-ELISA assays. We assessed individual, household, and community factors associated with a positive result for CHIKV or ZIKV after adjusting for confounders. During 2018-2019, 4,090 participants were enrolled; 61% were female and median age was 28y (interquartile range [IQR]: 16-41). Among 4,035 participants tested for CHIKV, 1,268 (31.4%) had evidence of previous infection. CHIKV infection prevalence was lower among children 1-10 years old compared to people 11 and older (adjusted odds ratio [aOR] 2.30; 95% CI 1.71-3.08). Lower CHIKV infection prevalence was associated with home screens (aOR 0.51; 95% CI 0.42-0.61) and air conditioning (aOR 0.64; 95% CI 0.54-0.77). CHIKV infection prevalence also varied by study cluster of residence and insurance type. Few participants (16; 0.4%) had evidence of recent DENV infection by IgM. Among 4,035 participants tested for ZIKV, 651 (16%) had evidence of recent infection. Infection prevalence increased with older age, from 7% among 1-10y olds up to 19% among 41-50y olds (aOR 3.23; 95% CI 2.16-4.84). Males had an increased risk of Zika infection prevalence compared with females (aOR 1.31; 95% CI 1.09-1.57). ZIKV infection prevalence also decreased with the presence of home screens (aOR 0.66; 95% CI 0.54-0.82) and air conditioning (aOR 0.69; 95% CI 0.57-0.84). Similar infection patterns were observed for recent ZIKV infection prevalence and previous CHIKV infection prevalence by age, and the presence of screens and air conditioners in the home decreased infection risk from both viruses by as much as 50%.

DOI: https://doi.org/10.1371/journal.pntd.0010416
Malar J. 2022 Jun 11. 21(1): 184

High asymptomatic malaria among seasonal migrant workers departing to home from malaria endemic areas in northwest Ethiopia.

Tesfaye Tilaye, Belay Tessema, Kassahun Alemu.

   BACKGROUND: In Ethiopia, thousands of seasonal migrant workers travel from non-malaria or mild malaria transmission areas to malaria-endemic areas for seasonal farm activities. Most of these migrants stay in the farm areas for land preparation, plowing, planting, weeding, and harvesting for a specific period and return to their living areas. However, there is limited evidence of how seasonal migrant workers contribute to the transmission of malaria to new or less malaria transmission areas.
METHODS: A cross-sectional study was conducted at the departure phase of seasonal migrant workers in the Metema district from September 2018 to October 2019. A total of 1208 seasonal migrant workers were interviewed during their departure from farm sites to their homes. The face-to-face interviews were performed using a pretested structured questionnaire. Moreover, blood samples were collected from each study participant for microscopic malaria parasite examination. The data were fitted with the logistic regression model to estimate the predictors of malaria transmission.
RESULTS: At departure to home, the prevalence of malaria among seasonal migrant workers was 17.5% (15.6-19.45%). Approximately 71.80% (177/212) of the cases were Plasmodium falciparum, and 28.20% (35/212) were Plasmodium vivax. Most seasonal migrant workers 934 (77.4%) were from rural residences and highlanders 660 (55%). Most 661 (55.4%) of the migrants visited two and more farm sites during their stay at development corridors for harvesting activities. Approximately 116 (54.7%) asymptomatic malaria cases returned to the Dembia 46 (21.7%), Chilaga 46 (19.8%) and Metema 28 (13.2%) districts.
CONCLUSION: In this study, asymptomatic malaria remains high among seasonal migrant workers departing to home from malaria endemic areas. This may fuel a resurgence of malaria transmission in the high lands and cause challenges to the country's malaria prevention and elimination efforts. Hence, tailored interventions for seasonal migrant workers could be in place to enhance malaria control and elimination in Ethiopia, such as asymptomatic malaria test and treat positive cases at departure and transit, and integration between malaria officers at their origin and departure for further follow-up to decrease any risk of spread at the origin.

Keywords:  Asymptomatic malaria; Malaria transmission; Seasonal migrant workers

DOI:  https://doi.org/10.1186/s12936-022-04211-9
PLoS Negl Trop Dis. 2022 Jun 17. 16(6): e0010457

Socioeconomic disparities associated with symptomatic Zika virus infections in pregnancy and congenital microcephaly: A spatiotemporal analysis from Goiânia, Brazil (2016 to 2020).

Luiza Emylce Pela Rosado, Erika Carvalho de Aquino, Elizabeth Bailey Brickley, Divania Dias da Silva França, Fluvia Pereira Amorim Silva, Vinicius Lemes da Silva, Angela Ferreira Lopes, Marilia Dalva Turchi.

The Zika virus (ZIKV) epidemic, which was followed by an unprecedented outbreak of congenital microcephaly, emerged in Brazil unevenly, with apparent pockets of susceptibility. The present study aimed to detect high-risk areas for ZIKV infection and microcephaly in Goiania, a large city of 1.5 million inhabitants in Central-West Brazil. Using geocoded surveillance data from the Brazilian Information System for Notifiable Diseases (SINAN) and from the Public Health Event Registry (RESP-microcefalia), we analyzed the spatiotemporal distribution and socioeconomic indicators of laboratory confirmed (RT-PCR and/or anti-ZIKV IgM ELISA) symptomatic ZIKV infections among pregnant women and clinically confirmed microcephaly in neonates, from 2016 to 2020. We investigated temporal patterns by estimating the risk of symptomatic maternal ZIKV infections and microcephaly per 1000 live births per month. We examined the spatial distribution of maternal ZIKV infections and microcephaly cases across the 63 subdistricts of Goiania by manually plotting the geographical coordinates. We used spatial scan statistics estimated by discrete Poisson models to detect high clusters of maternal ZIKV infection and microcephaly and compared the distributions by socioeconomic indicators measured at the subdistrict level. In total, 382 lab-confirmed cases of maternal ZIKV infections, and 31 cases of microcephaly were registered in the city of Goiania. More than 90% of maternal cases were reported between 2016 and 2017. The highest incidence of ZIKV cases among pregnant women occurred between February and April 2016. A similar pattern was observed in the following year, although with a lower number of cases, indicating seasonality for ZIKV infection, during the local rainy season. Most congenital microcephaly cases occurred with a time-lag of 6 to 7 months after the peak of maternal ZIKV infection. The highest estimated incidence of maternal ZIKV infections and microcephaly were 39.3 and 2.5 cases per 1000 livebirths, respectively. Districts with better socioeconomic indicators and with higher proportions of self-identified white inhabitants were associated with lower risks of maternal ZIKV infection. Overall, the findings indicate heterogeneity in the spatiotemporal patterns of maternal ZIKV infections and microcephaly, which were correlated with seasonality and included a high-risk geographic cluster. Our findings identified geographically and socio-economically underprivileged groups that would benefit from targeted interventions to reduce exposure to vector-borne infections.

DOI: https://doi.org/10.1371/journal.pntd.0010457