bims-mosdis 2022-08-14 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–08–14
fourteen papers selected by
Richard Halfpenny, Staffordshire University

Detection and Co-occurrence of kdr (F1534C and S989P) Mutations in Multiple Insecticides Resistant Aedes aegypti (Diptera: Culicidae) in Nigeria.
Detection and persistence of environmental DNA (eDNA) of the different developmental stages of a vector mosquito, Culex pipiens pallens.
Prevalence of Plasmodium spp. in Anopheles mosquitoes in Thailand: a systematic review and meta-analysis.
Persistently high proportions of plasmodium-infected Anopheles funestus mosquitoes in two villages in the Kilombero valley, South-Eastern Tanzania.
Stress-Mediated Responses of Aedes aegypti (Diptera: Culicidae) Larvae When Exposed to Metarhizium brunneum (Hypocreales: Clavicipitaceae) and Toxorhynchites brevipalpis (Diptera: Culicidae).
Survival and Fecundity of Anopheles stephensi and Anopheles albimanus Mosquitoes (Diptera: Culicidae) After Ingesting Bovine Blood Containing Various Veterinary Systemic Parasiticides.
Effect of School-Based Educational Interventions on the Knowledge of Malaria and Dengue Among Higher Secondary School Children in Chennai, India: A Pre and Post-intervention Study.
Spatio-temporal Prediction of the Malaria Transmission Risk in Minab District (Hormozgan Province, Southern Iran).
The new invasive mosquito species Aedes koreicus as vector-borne diseases in the European area, a focus on Italian region: What we know from the scientific literature.
Influence of social and environmental factors for Culex quinquefasciatus distribution in Northeastern Brazil: a risk index.
Epidemiologic and environmental characterization of the Re-emergence of St. Louis Encephalitis Virus in California, 2015-2020.
KEY TO THE ADULT FEMALES OF SPECIES OF CULEX SUBGENUS MELANOCONION IN FLORIDA, USA.
Forecasting the Potential Effects of Climate Change on Malaria in the Lake Victoria Basin Using Regionalized Climate Projections.
Prediction of malaria using deep learning models: A case study on city clusters in the state of Amazonas, Brazil, from 2003 to 2018.

J Med Entomol. 2022 Aug 12. pii: tjac114. [Epub ahead of print]

Detection and Co-occurrence of kdr (F1534C and S989P) Mutations in Multiple Insecticides Resistant Aedes aegypti (Diptera: Culicidae) in Nigeria.

Ifeoluwa Kayode Fagbohun, Tolulope Amos Oyeniyi, Emmanuel Taiwo Idowu, Oge Nwanya, Felix Okonkwo, Kemi O Adesalu, Romoke T Jimoh, Yusuff Oladosu, Olubunmi Adetoro Otubanjo, Adedapo O Adeogun.

  The outbreak of yellow fever virus transmitted by Aedes aegypti has been of major concern in Nigeria, this mosquito also transmits several other arboviruses globally. The control of many vectors of mosquito-borne diseases relies heavily on the use of insecticides. Therefore, constant monitoring of insecticide resistance status and associated mechanisms is crucial within the local mosquito population. Here, we determined the resistance profile of adult Ae. aegypti from Majidun and Oke Ota communities, Ikorodu Local Government Area of Lagos State, Nigeria to different classes of insecticides using WHO procedures. The resistant phenotypes of Ae. aegypti were screened for the presence of kdr mutations F1534C, S989P, and V1016G, which have been implicated in insecticide resistance in yellow fever vectors. A high level of resistance to DDT and pyrethroids was recorded in Ae. aegypti in this study, although possible resistance to deltamethrin, one of the pyrethroids was reported in one of the locations. Resistance to bendiocarb was recorded in the Majidun community while Ae. aegypti in both locations were susceptible to malathion. The presence of F1534C mutation associated with DDT and deltamethrin resistance in Ae. aegypti population, and the presence of S989P mutation were detected singly and in co-occurrence with F1534C for the first time in Africa, while V1016G mutation was not detected in this study. The role of these mutations in resistance phenotype expressed in Ae. aegypti in larger populations needs to be established.

Keywords:   Aedes ; bendiocarb; organochlorine; pyrethroid; resistance

DOI:  https://doi.org/10.1093/jme/tjac114
PLoS One. 2022 ;17(8): e0272653

Detection and persistence of environmental DNA (eDNA) of the different developmental stages of a vector mosquito, Culex pipiens pallens.

Masayuki K Sakata, Megumi Sato, Marcello Otake Sato, Tomoe Watanabe, Honami Mitsuishi, Tomoyuki Hikitsuchi, Jun Kobayashi, Toshifumi Minamoto.

Preventing mosquito-borne infectious diseases requires that vector mosquitoes are monitored and controlled. Targeting immature mosquitoes (eggs, larvae, and pupae), which have less mobility than adults, is an effective management approach. However, conducting these surveys is often difficult due to the limitations of morphological classification and survey costs. The application of environmental DNA (eDNA) analysis can solve these issues because it allows easy estimation of species distribution and morphology-independent species identification. Although a few previous studies have reported mosquito eDNA detection, there is a gap in knowledge regarding the dynamics related to the persistence of immature mosquito eDNA. We used Culex pipiens pallens, a vector of West Nile fever, as a model species. First, we developed a species-specific detection assay and confirmed its specificity using in silico and in vitro tests. Next, we conducted laboratory experiments using breeding tanks. Water samples were collected at each developmental stage. In addition, water samples were collected daily until the seventh day after emergence from the pupae. We quantified eDNA using real-time PCR with the developed assay to investigate the dynamics of mosquito eDNA. The specificity of the developed assay was confirmed by in silico and in vitro tests. Mosquito eDNA was detected at all developmental stages and detected up to seven days after emergence of pupae. In particular, high concentrations of eDNA were detected immediately after hatching from eggs and after emergence from pupae. Highly frequent positive eDNA signals were continuously detected between egg hatching and pupa hatching. Mosquito eDNA was detected immediately after the eggs were introduced, and eDNA-positive detections continued until pupae emergence, suggesting that eDNA analysis is useful for monitoring mosquito larvae. In the future, monitoring immature mosquitoes using eDNA analysis will contribute to prevent mosquito-borne infectious diseases.

DOI: https://doi.org/10.1371/journal.pone.0272653
Parasit Vectors. 2022 Aug 06. 15(1): 285

Prevalence of Plasmodium spp. in Anopheles mosquitoes in Thailand: a systematic review and meta-analysis.

Chutipong Sukkanon, Frederick Ramirez Masangkay, Wanida Mala, Kwuntida Uthaisar Kotepui, Polrat Wilairatana, Theeraphap Chareonviriyaphap, Manas Kotepui.

   BACKGROUND: The entomological inoculation rate (EIR) is one of the key indices used to evaluate malaria transmission and vector control interventions. One of the components of the EIR is the sporozoite rate in Anopheles vectors. A systematic review and meta-analysis was performed to identify the prevalence of Plasmodium spp. in field-collected Anopheles species across Thailand.
METHODS: This systematic review was registered under the PROSPERO number CRD42021297255. Studies that focused on the identification of Plasmodium spp. in Anopheles mosquitoes were identified from the electronic databases PubMed, Web of Science, and Scopus. The quality of the identified studies was determined using the Strengthening the Reporting of Observational Studies in Epidemiology approach. The proportion of Anopheles mosquitoes collected, Anopheles vectors for Plasmodium species, and specificity of Anopheles vectors for Plasmodium species were analyzed. The pooled prevalence of Plasmodium species among the primary vectors (Anopheles dirus, Anopheles minimus, and Anopheles maculatus) was estimated using the random-effects model.
RESULTS: Of the 1113 studies identified, 31 were included in the syntheses. Of the 100,910 Anopheles mosquitoes identified for species and sibling species, An. minimus (40.16%), An. maculatus (16.59%), and Anopheles epiroticus (9.18%) were the most prevalent Anopheles species. Of the 123,286 Anopheles mosquitoes identified, 566 (0.46%) were positive for Plasmodium species. The highest proportions of Plasmodium species were identified in Anopheles hodgkini (2/6, 33.3%), Anopheles nigerrimus (2/24, 8.33%), Anopheles balabacensis (4/84, 4.76%), An. dirus (114/4956, 2.3%), Anopheles annularis (16/852, 1.88%), Anopheles kochi (8/519, 1.54%), Anopheles vagus (3/215, 1.4%), and Anopheles baimaii (1/86, 1.16%). The pooled prevalence of Plasmodium species identified in the main Anopheles vectors was 0.4% of that of Plasmodium species identified in An. dirus was 2.1%, that of Plasmodium species identified in An. minimus was 0.4%, and that of Plasmodium species identified in An. maculatus was 0.4%.
CONCLUSIONS: We found a low prevalence of Plasmodium infection in Anopheles mosquitoes across Thailand. Therefore, the use of EIR to determine the impact of vector control intervention on malaria parasite transmission and elimination in Thailand must be undertaken with caution, as a large number of Anopheles specimens may be required.

Keywords:  Anopheles; Meta-analysis; Plasmodium; Thailand

DOI:  https://doi.org/10.1186/s13071-022-05397-2
Parasite Epidemiol Control. 2022 Aug;18 e00264

Persistently high proportions of plasmodium-infected Anopheles funestus mosquitoes in two villages in the Kilombero valley, South-Eastern Tanzania.

Salum A Mapua, Emmanuel E Hape, Japhet Kihonda, Hamis Bwanary, Khamis Kifungo, Masoud Kilalangongono, Emmanuel W Kaindoa, Halfan S Ngowo, Fredros O Okumu.

   Background: In south-eastern Tanzania where insecticide-treated nets have been widely used for >20 years, malaria transmission has greatly reduced but remains highly heterogenous over small distances. This study investigated the seasonal prevalence of Plasmodium sporozoite infections in the two main malaria vector species, Anopheles funestus and Anopheles arabiensis for 34 months, starting January 2018 to November 2020.
Methods: Adult mosquitoes were collected using CDC-light traps and Prokopack aspirators inside local houses in Igumbiro and Sululu villages, where earlier surveys had found very high densities of An. funestus. Collected females were sorted by taxa, and the samples examined using ELISA assays for detecting Plasmodium circumsporozoite protein in their salivary glands.
Results: Of 7859 An. funestus tested, 4.6% (n = 365) were positive for Pf sporozoites in the salivary glands. On the contrary, only 0.4% (n = 9) of the 2382 An. arabiensis tested were positive. The sporozoite prevalence did not vary significantly between the villages or seasons. Similarly, the proportions of parous females of either species were not significantly different between the two villages (p > 0.05) but was slightly higher in An. funestus (0.50) than in An. arabiensis (0.42). Analysis of the 2020 data determined that An. funestus contributed 97.7% of all malaria transmitted in households in these two villages.
Conclusions: In contexts where individual vector species mediate most of the pathogen transmission, it may be most appropriate to pursue a species-focused approach to better understand the ecology of the dominant vectors and target them with effective interventions to suppress transmission. Despite the ongoing efforts on tackling malaria in the two study villages, there is still persistently high Plasmodium infection prevalence in local populations of An. funestus, which now carry ~97% of all malaria infections and mediates intense year-round transmission. Further reduction in malaria burden in these or other similar settings requires effective targeting of An. funestus.

Keywords:  Anopheles funestus; CDC, Centers for Diseases Control and Prevention; ELISA, Enzyme-Linked Immunosorbent Assay; GLM, Generalized Linear Model; GLMM, Generalized Linear Mixed Model; IRS, Indoor Residual Spraying; ITN, Insecticide-Treated Net; Ifakara health institute; Kilombero valley; LLINs, Long-Lasting Insecticidal Nets; Malaria transmission; NMSP, National Malaria Strategic Plan; PCR, Polymerase Chain Reaction; Pf-CSP, Plasmodium falciparum Circumsporozoite Protein; Plasmodium; Sporozoite prevalence; Tanzania

DOI:  https://doi.org/10.1016/j.parepi.2022.e00264
J Med Entomol. 2022 Aug 08. pii: tjac110. [Epub ahead of print]

Stress-Mediated Responses of Aedes aegypti (Diptera: Culicidae) Larvae When Exposed to Metarhizium brunneum (Hypocreales: Clavicipitaceae) and Toxorhynchites brevipalpis (Diptera: Culicidae).

Martyn J Wood, Abeer M Alkhaibari, Tariq M Butt.

  Aedes aegypti mosquitoes are capable of vectoring a wide range of diseases including dengue, yellow fever, and Zika viruses, with approximately half of the worlds' population at risk from such diseases. Development of combined predator-parasite treatments for the control of larvae consistently demonstrates increased efficacy over single-agent treatments, however, the mechanism behind the interaction remains unknown. Treatments using the natural predator Toxorhynchites brevipalpis and the entomopathogenic fungus Metarhizium brunneum were applied in the laboratory against Ae. aegypti larvae as both individual and combined treatments to determine the levels of interaction between control strategies. Parallel experiments involved the removal of larvae from test arenas at set intervals during the course of the trial to record whole body caspase and phenoloxidase activities. This was measured via luminometric assay to measure larval stress factors underlying the interactions. Combined Metarhizium and Toxorhynchites treatments were seen to drastically reduce lethal times as compared to individual treatments. This was accompanied by increased phenoloxidase and caspase activities in combination treatments after 18 h (p < 0.001). The sharp increases in caspase and phenoloxidase activities suggest that combined treatments act to increase stress factor responses in the larvae that result in rapid mortality above that of either control agent individually. This work concludes that the underlying mechanism for increased lethality in combined parasite-predator treatments may be related to additive stress factors induced within the target host larvae.

Keywords:   Aedes ; Metarhizium ; Toxorhynchites ; caspase; phenoloxidase

DOI:  https://doi.org/10.1093/jme/tjac110
J Med Entomol. 2022 Aug 08. pii: tjac103. [Epub ahead of print]

Survival and Fecundity of Anopheles stephensi and Anopheles albimanus Mosquitoes (Diptera: Culicidae) After Ingesting Bovine Blood Containing Various Veterinary Systemic Parasiticides.

Staci M Dreyer, Jefferson A Vaughan.

  Systemic parasiticides in livestock can control zoophilic malaria vectors that contribute to residual malaria transmission. Membrane feeding techniques were used to screen seven systemic parasiticidic drugs currently in veterinary use for livestock and dogs. Drugs were tested in two laboratory strains of zoophilic Anopheles - A. stephensi (South Asian vector) and A. albimanus (Central American vector). To assess the relative potentials of these drugs, the resultant LC-50 for each drug was compared with what is known about the pharmacokinetic of the drug. Drugs with LC-50 values below the reported maximum plasma concentration of treated animals were considered as showing the most promise for use in the field. Ivermectin and fipronil showed the greatest promise for use in cattle against A. stephensi. Fipronil showed the greatest promise for use in cattle against A. albimanus. Both fluralaner and afoxolaner were highly effective against both mosquito species but pharmacokinetic data for these drugs in cattle are lacking. Eprinomectin, moxidectin and abamectin showed marginal to no promise for either mosquito species. At sublethal doses, ivermectin, fipronil, and afoxolaner (but not fluralaner) significantly reduced the larval production of surviving A. stephensi and A. albimanus. Further testing of candidate systemic parasiticides, including their product formulations, in livestock against field-collected populations of Anopheles is the next logical step toward full implementation of this strategy to manage zoophilic vectors.

Keywords:   Anopheles albimanus ; Anopheles stephensi ; fipronil; isoxazoline; macrocyclic lactone

DOI:  https://doi.org/10.1093/jme/tjac103
Cureus. 2022 Jul;14(7): e26536

Effect of School-Based Educational Interventions on the Knowledge of Malaria and Dengue Among Higher Secondary School Children in Chennai, India: A Pre and Post-intervention Study.

Chokkara Roja, Avudaiappan Seetha Lakshmi, M Anitha Rani, Alex Eapen.

   INTRODUCTION: School children are a means to reach and sensitize the community on the prevention of seasonal diseases such as malaria and dengue. The current study aims to determine the impact of school-based educational interventions on the knowledge of students toward the prevention and control of malaria and dengue in higher secondary schools.
METHODS: This pre- and post-intervention study was conducted in three higher secondary schools in Zone IV, North Chennai, from September to December 2021. A total of 284 students in the age group of 13-17 years participated in the study. School-based educational interventions were delivered through PowerPoint-assisted lectures, participatory group activities, and demonstration of mosquito larvae and their control. The impact of the interventions as the change in knowledge level was analyzed using McNemar's test, with a p-value of <0.05.
RESULTS: Educational interventions led to the improvement in knowledge about malaria symptoms, such as fever (43.7% to 76.1%; p<0.001), chills (45.1% to 82.4%; p<0.001), and headache (46.1% to 86.6%; p<0.001), and the knowledge of Aedes mosquito bites as the cause of dengue transmission enhanced (41.9% to 92.2%; p<0.001). Similarly, there was an increase in knowledge on the identification of vector mosquito breeding sites inside the house (11.9% to 67.9%; p<0.001) and outside the house (10.9% to 69.7%; p<0.001) and mosquito net usage (21.5% to 76.1%; p<0.001) after the interventions.
CONCLUSION: School-based educational interventions had a significant impact on enhancing the knowledge on the prevention and control of malaria and dengue among school children. Involving school children can strengthen existing malaria and dengue prevention and control strategies in endemic areas.

Keywords:  control; dengue; health education; knowledge; malaria; prevention; school children; school-based interventions

DOI:  https://doi.org/10.7759/cureus.26536
Acta Parasitol. 2022 Aug 11.

Spatio-temporal Prediction of the Malaria Transmission Risk in Minab District (Hormozgan Province, Southern Iran).

Abdolreza Salahi-Moghaddam, Habibollah Turki, Masoud Yeryan, Màrius V Fuentes.

   INTRODUCTION: Malaria is the most important parasitic disease in tropical and subtropical regions, with more than 240 million cases reported annually. In Iran, indigenous cases occur in its south-eastern region. The aim of this study is to assess the environmental risk of malaria transmission in an endemic area of southern Iran.
METHODS: The study was carried out in Minab district (Hormozgan province, southern Iran), with the aim to assess the environmental risk of malaria, based on a spatio-temporal study, using Growing Degree Days (GDD)-based predictions, larval habitat ecology, MaxEnt spatial predictions and malaria transmission data.
RESULTS: The Gradient Model Risk index showed the highest malaria transmission risk period to be during January-April and October-December. The ecological conditions of water bodies of larval habitats of the four vector species (Anopheles culicifacies, A. dthali, A. fluviatilis and A. stephensi) were assessed, with A. stephensi being the most prevalent and the most widely distributed species.
CONCLUSION: These findings, together with the MaxEnt Anopheles predictive distribution models, allowed identifying villages in danger of malaria transmission in Minab district. This spatio-temporal prediction of malaria transmission risk should be incorporated in the design of malaria control initiatives towards a local malaria early warning system. Moreover, the proposed transmission risk model can be extrapolated, at local scale, to other malaria endemic areas of tropical and subtropical regions.

Keywords:  Anopheline larvae; Environmental risk; GIS; Hormozgan province; Iran; Malaria

DOI:  https://doi.org/10.1007/s11686-022-00598-2
Front Microbiol. 2022 ;13 931994

The new invasive mosquito species Aedes koreicus as vector-borne diseases in the European area, a focus on Italian region: What we know from the scientific literature.

Sonia Ganassi, Antonio De Cristofaro, Dalila Di Criscio, Sonia Petrarca, Chiara Leopardi, Antonio Guarnieri, Laura Pietrangelo, Noemi Venditti, Roberto Di Marco, Giulio Petronio Petronio.

  The increased mobility of goods, people, and animals worldwide has caused the spread of several arthropod vectors, leading to an increased risk of animal and human infections. Aedes koreicus is a common species in South Korea, China, Japan, and Russia. Due to its cold-resistant dormant eggs, the adults last from the late summer until the autumn seasons. For these reasons, it seems to be better adapted to colder temperatures, favoring its colonization of hilly and pre-alpine areas. Its first appearance in Europe was in 2008 in Belgium, where it is currently established. The species was subsequently detected in Italy in 2011, European Russia, Germany, the Swiss-Italian border region, Hungary, Slovenia, Crimea, Austria, the Republic of Kazakhstan, and the Netherlands. The role of A. koreicus in the transmission of vector-borne pathogens remains unclear. The available scientific evidence is very old, often not available in English or not indexed in international databases, and therefore difficult to find. According to the literature reviewed, A. koreicus can be considered a new invasive mosquito species in Europe, establishing populations on the European continent. In addition, experimental evidence demonstrated its vector competence for both Dirofilaria immitis and Chikungunya and is relatively low for ZIKA but not for Western Nile Virus. On the other hand, even if the field evidence does not confirm the experimental findings, it is currently not possible to exclude with absolute certainty the potential involvement of this species in the spread, emergence, or re-emergence of these vector-borne disease agents.

Keywords:  Alphavirus; Flavivirus; Korean bush mosquito; hematophagous arthropod; nematodes

DOI:  https://doi.org/10.3389/fmicb.2022.931994
Int J Environ Health Res. 2022 Aug 11. 1-11

Influence of social and environmental factors for Culex quinquefasciatus distribution in Northeastern Brazil: a risk index.

Amanda Xavier, Cristine Bonfim, Walter Barbosa Júnior, Gilberto Bezerra, Claudia Oliveira, Rodrigo Uchikawa, Filipe da Silva, Ana Aguiar-Santos, Zulma Medeiros.

  Culex quinquefasciatus is a vector of lymphatic filariasis. One important component in planning filariasis control activities is the mapping of vector distribution. A tool that involves socio-environmental factors and Cx. quinquefasciatus density can contribute to the identification of areas that should be prioritized in surveillance actions. This is an ecological study based on the construction and validation of a risk score of urban areas according to social and environmental variables extracted from a national database. Based on this stratification, female Cx. quinquefasciatus were captured. In total, 30,635 Cx. quinquefasciatus were captured, of which 17,161 (56%) were females. The highest vector density index of mosquitoes were captured in households located in the high-risk stratum and the indicator proved to be a tool that identified an association between social and environmental conditions and areas with the highest vector density index of females Cx. quinquefasciatus.

Keywords:  Culex quinquefasciatus; lymphatic filariasis; vector control

DOI:  https://doi.org/10.1080/09603123.2022.2109603
PLoS Negl Trop Dis. 2022 Aug 08. 16(8): e0010664

Epidemiologic and environmental characterization of the Re-emergence of St. Louis Encephalitis Virus in California, 2015-2020.

Mary E Danforth, Robert E Snyder, Tina Feiszli, Teal Bullick, Sharon Messenger, Carl Hanson, Kerry Padgett, Lark L Coffey, Christopher M Barker, William K Reisen, Vicki L Kramer.

St. Louis encephalitis virus (SLEV) is an endemic flavivirus in the western and southeastern United States, including California. From 1938 to 2003, the virus was detected annually in California, but after West Nile virus (WNV) arrived in 2003, SLEV was not detected again until it re-emerged in Riverside County in 2015. The re-emerging virus in California and other areas of the western US is SLEV genotype III, which previously had been detected only in Argentina, suggesting a South American origin. This study describes SLEV activity in California since its re-emergence in 2015 and compares it to WNV activity during the same period. From 2015 to 2020, SLEV was detected in 1,650 mosquito pools and 26 sentinel chickens, whereas WNV was detected concurrently in 18,108 mosquito pools and 1,542 sentinel chickens from the same samples. There were 24 reported human infections of SLEV in 10 California counties, including two fatalities (case fatality rate: 8%), compared to 2,469 reported human infections of WNV from 43 California counties, with 143 fatalities (case fatality rate: 6%). From 2015 through 2020, SLEV was detected in 17 (29%) of California's 58 counties, while WNV was detected in 54 (93%). Although mosquitoes and sentinel chickens have been tested routinely for arboviruses in California for over fifty years, surveillance has not been uniform throughout the state. Of note, since 2005 there has been a steady decline in the use of sentinel chickens among vector control agencies, potentially contributing to gaps in SLEV surveillance. The incidence of SLEV disease in California may have been underestimated because human surveillance for SLEV relied on an environmental detection to trigger SLEV patient screening and mosquito surveillance effort is spatially variable. In addition, human diagnostic testing usually relies on changes in host antibodies and SLEV infection can be indistinguishable from infection with other flaviviruses such as WNV, which is more prevalent.

DOI: https://doi.org/10.1371/journal.pntd.0010664
J Am Mosq Control Assoc. 2022 Aug 08.

KEY TO THE ADULT FEMALES OF SPECIES OF CULEX SUBGENUS MELANOCONION IN FLORIDA, USA.

Nathan D Burkett-Cadena, Erik M Blosser, Lawrence E Reeves.

  The subgenus Melanoconion of Culex is a diverse and taxonomically challenging group of mosquitoes (Diptera: Culicidae) endemic to the American tropics, with a few species occurring in temperate regions. With the introduction and establishment of Culex (Melanoconion) panocossa in southern Florida, the existing taxonomic resources for identifying species of Melanoconion in Florida need updating. Here we provide an up-to-date photographic key for identifying females of Culex (Melanoconion) spp. known to occur in Florida, USA, and summarize relevant literature on the biology of each species. Given the challenge of identifying members of subgenus Melanoconion, updated resources for identifying females of this medically important group are warranted. The keys, photographs, and summarized biological information in this report should facilitate research, surveillance, and decisions regarding control.

Keywords:   Melanoconion ; Dichotomous key; Florida; taxonomy

DOI:  https://doi.org/10.2987/22-7081
Acta Parasitol. 2022 Aug 12.

Forecasting the Potential Effects of Climate Change on Malaria in the Lake Victoria Basin Using Regionalized Climate Projections.

Ednah N Ototo, Joseph O Ogutu, Andrew Githeko, Mohammed Y Said, Lucy Kamau, Didacus Namanya, Stella Simiyu, Stephen Mutimba.

   BACKGROUND: Malaria epidemics are increasing in East Africa since the 1980s, coincident with rising temperature and widening climate variability. A projected 1-3.5 °C rise in average global temperatures by 2100 could exacerbate the epidemics by modifying disease transmission thresholds. Future malaria scenarios for the Lake Victoria Basin (LVB) are quantified for projected climate scenarios spanning 2006-2100.
METHODS: Regression relationships are established between historical (1995-2010) clinical malaria and anaemia cases and rainfall and temperature for four East African malaria hotspots. The vector autoregressive moving average processes model, VARMAX (p,q,s), is then used to forecast malaria and anaemia responses to rainfall and temperatures projected with an ensemble of eight General Circulation Models (GCMs) for climate change scenarios defined by three Representative Concentration Pathways (RCPs 2.6, 4.5 and 8.5).
RESULTS: Maximum temperatures in the long rainy (March-May) and dry (June-September) seasons will likely increase by over 2.0 °C by 2070, relative to 1971-2000, under RCPs 4.5 and 8.5. Minimum temperatures (June-September) will likely increase by over 1.5-3.0 °C under RCPs 2.6, 4.5 and 8.5. The short rains (OND) will likely increase more than the long rains (MAM) by the 2050s and 2070s under RCPs 4.5 and 8.5. Historical malaria cases are positively and linearly related to the 3-6-month running means of monthly rainfall and maximum temperature. Marked variation characterizes the patterns projected for each of the three scenarios across the eight General Circulation Models, reaffirming the importance of using an ensemble of models for projections.
CONCLUSIONS: The short rains (OND), wet season (MAM) temperatures and clinical malaria cases will likely increase in the Lake Victoria Basin. Climate change adaptation and mitigation strategies, including malaria control interventions could reduce the projected epidemics and cases. Interventions should reduce emerging risks, human vulnerability and environmental suitability for malaria transmission.

Keywords:  Climate change; Malaria; Regionalized climate projections

DOI:  https://doi.org/10.1007/s11686-022-00588-4
Rev Soc Bras Med Trop. 2022 ;pii: S0037-86822022000100324. [Epub ahead of print]55 e0420

Prediction of malaria using deep learning models: A case study on city clusters in the state of Amazonas, Brazil, from 2003 to 2018.

Matheus Félix Xavier Barboza, Kayo Henrique de Carvalho Monteiro, Iago Richard Rodrigues, Guto Leoni Santos, Wuelton Marcelo Monteiro, Elder Augusto Guimaraes Figueira, Vanderson de Souza Sampaio, Theo Lynn, Patricia Takako Endo.

BACKGROUND: Malaria is curable. Nonetheless, over 229 million cases of malaria were recorded in 2019, along with 409,000 deaths. Although over 42 million Brazilians are at risk of contracting malaria, 99% percent of all malaria cases in Brazil are located in or around the Amazon rainforest. Despite declining cases and deaths, malaria remains a major public health issue in Brazil. Accurate spatiotemporal prediction of malaria propagation may enable improved resource allocation to support efforts to eradicate the disease.
METHODS: In response to calls for novel research on malaria elimination strategies that suit local conditions, in this study, we propose machine learning (ML) and deep learning (DL) models to predict the probability of malaria cases in the state of Amazonas. Using a dataset of approximately 6 million records (January 2003 to December 2018), we applied k-means clustering to group cities based on their similarity of malaria incidence. We evaluated random forest, long-short term memory (LSTM) and dated recurrent unit (GRU) models and compared their performance.
RESULTS: The LSTM architecture achieved better performance in clusters with less variability in the number of cases, whereas the GRU presents better results in clusters with high variability. Although Diebold-Mariano testing suggested that both the LSTM and GRU performed comparably, GRU can be trained significantly faster, which could prove advantageous in practice.
CONCLUSIONS: All models showed satisfactory accuracy and strong performance in predicting new cases of malaria, and each could serve as a supplemental tool to support regional policies and strategies.

DOI: https://doi.org/10.1590/0037-8682-0420-2021