bims-mosdis 2022-11-27 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–11–27
twenty papers selected by
Richard Halfpenny, Staffordshire University

How do attitudes shape protective practices against the Asian tiger mosquito in community gardens in a nonendemic country?
Distribution of Insecticide Resistance Genetic Markers in the West Nile Virus Vector Culex pipiens from South-Eastern Romania.
What sounds like Aedes, acts like Aedes, but is not Aedes? Lessons from dengue virus control for the management of invasive Anopheles.
Comparison of diurnal biting activity, life table, and demographic attributes of Aedes albopictus (asian tiger mosquito) from different urbanized settings in West Java, Indonesia.
An epidemiological model for mosquito host selection and temperature-dependent transmission of West Nile virus.
Epidemiological, Entomological, and Climatological Investigation of the 2019 Dengue Fever Outbreak in Gewane District, Afar Region, North-East Ethiopia.
Developing radiation-based sterile insect technique (SIT) for controlling Aedes aegypti: identification of a sterilizing dose.
Field Evaluation of Novel Spatial Repellent Controlled Release Devices (CRDs) against Mosquitoes in an Outdoor Setting in the Northern Peruvian Amazon.
Phylogenetic Analysis of Wesselsbron Virus Isolated from Field-Captured Mosquitoes during a Rift Valley Fever Outbreak in Kabale District, Uganda-2016.
Pattern of Aedes aegypti and Aedes albopictus Associated with Human Exposure to Dengue Virus in Kinshasa, the Democratic Republic of the Congo.
Community Participation in Habitat Management and Larviciding for the Control of Malaria Vectors in Southern Malawi.
Malaria Vector Surveillance and Control in an Elimination Setting in South Africa.
Exploring Potential Determinants of Mosquito Net Ownership and Use in Somalia: A Cross-Sectional Study.
Retrospective spatiotemporal analysis of malaria cases reported between 2000 and 2020 in North Carolina, USA.
Yellow Fever: A Perennial Threat.
Assessment of knowledge of malaria and its control practices in mining and sugarcane growing regions of Western Kenya highlands.
Entomopathogenic Nematodes and Their Symbiotic Bacteria from the National Parks of Thailand and Larvicidal Property of Symbiotic Bacteria against Aedes aegypti and Culex quinquefasciatus.
Mosquito Larvicides of Partial and Combinations Extract of Ethnobotanical Plant from North Sulawesi, Indonesia.
RNAi-mediated knockdown of arginine kinase genes leads to high mortality and negatively affect reproduction and blood-feeding behavior of Culex pipiens pallens.
Chikungunya: An Emerging Public Health Concern.

Parasit Vectors. 2022 Nov 22. 15(1): 439

How do attitudes shape protective practices against the Asian tiger mosquito in community gardens in a nonendemic country?

Pénélope Duval, Claire Valiente Moro, Christina Aschan-Leygonie.

   BACKGROUND: The Asian tiger mosquito Aedes albopictus is responsible for the transmission of many arboviruses worldwide and is well adapted to thrive in urban environments. In mainland France, a nonendemic area, this mosquito is responsible for several autochthonous and imported cases of chikungunya and dengue each year. Better management and prevention of mosquito-borne disease transmission in nonendemic areas is thus of global concern. In this context, the aim of this study was to provide a better understanding of mosquito-human interactions as well as human behavior and beliefs in regard to this mosquito species in urban areas.
METHODS: We focused on people who participate in community gardens, which are increasingly popular initiatives in metropolitan France and are conducive to the development of tiger mosquitoes. To evaluate community gardeners' knowledge and practices in relation to mosquito management and control, we conducted a knowledge, attitude, and practice (KAP) survey.
RESULTS: In contrast to previous KAP studies, we showed that attitudes, more than knowledge, influence the practices of community gardeners in relation to mosquitoes. Interestingly, all gardeners who participated in the survey were concerned about the Asian tiger mosquito and were motivated to incorporate mosquito control methods in their gardens. Moreover, mosquitoes were perceived as nuisances rather than disease vector species. A change in community gardeners' perceptions could facilitate more appropriate behavior to control this species.
CONCLUSIONS: This survey reveals the lack of knowledge and awareness of good practices for the efficient control of the Asian tiger mosquito in green urban areas.

Keywords:  Asian tiger mosquito; Green urban area; KAP survey; Nonendemic country; Protective practices

DOI:  https://doi.org/10.1186/s13071-022-05520-3
Insects. 2022 Nov 17. pii: 1062. [Epub ahead of print]13(11):

Distribution of Insecticide Resistance Genetic Markers in the West Nile Virus Vector Culex pipiens from South-Eastern Romania.

Ioana Georgeta Stancu, Florian Liviu Prioteasa, Georgiana Victorița Tiron, Ani Ioana Cotar, Elena Fălcuță, Daniela Porea, Sorin Dinu, Cornelia Svetlana Ceianu, Ortansa Csutak.

  Culex pipiens pipiens and Culex pipiens molestus mosquitoes are the vectors of West Nile virus in south-eastern Romania, an area of intense circulation and human transmission of this virus. The level of insecticide resistance for the mosquito populations in the region has not been previously assessed. Culex pipiens mosquitoes collected between 2018 and 2019 in south-eastern Romania from different habitats were subjected to biotype identification by real-time PCR. Substitutions causing resistance to organophosphates and carbamates (F290V and G119S in acetylcholinesterase 1) and to pyrethroids (L1014F in voltage gated Na+ channel) were screened by PCR or sequencing. Substitutions F290V and G119S were detected at very low frequencies and only in heterozygous state in Culex pipiens molestus biotype specimens collected in urban areas. The molestus biotype population analysed was entirely homozygous for L1014F, and high frequencies of this substitution were also found for pipiens biotype and hybrid mosquitoes collected in urban and in intensive agriculture areas. Reducing the selective pressure by limiting the use of pyrethroid insecticides only for regions where it is absolutely necessary and monitoring L1014F mutation should be taken into consideration when implementing vector control strategies.

Keywords:  Culex pipiens; insecticide resistance; molestus biotype; pipiens biotype; pyrethroids

DOI:  https://doi.org/10.3390/insects13111062
Lancet Glob Health. 2022 Nov 22. pii: S2214-109X(22)00454-5. [Epub ahead of print]

What sounds like Aedes, acts like Aedes, but is not Aedes? Lessons from dengue virus control for the management of invasive Anopheles.

Richard Allan, Sophie Budge, Hendrik Sauskojus.

Aedes mosquitoes are responsible for transmission of dengue, chikungunya, Zika, and yellow fever viruses. Aedes mosquitoes are the pathfinders of invasive urban-living mosquitoes, and have spread into 129 countries over the past five decades. In the past 10 years Anopheles stephensi has been identified within densely populated cities in Yemen and across the Horn of Africa and as far west as Nigeria. A stephensi's aggressive spread is closely linked to increases in population movement due to migration, conflict, and climate change; rapid unplanned urbanisation; and resulting poor water quality, sanitation, waste container removal, and hygiene systems. As a highly invasive vector that is adept at transmitting malarial pathogens (eg, Plasmodium vivax and Plasmodium falciparum), A stephensi's spread holds huge implications for increasing malaria morbidity and mortality. Both vectors (ie, Aedes species and A stephensi) thrive in the same urban environments, and urgent action is needed to seize the opportunity to integrate disease control resources and generate innovative vector-control tools for urban populations, to protect the many millions at risk.

DOI: https://doi.org/10.1016/S2214-109X(22)00454-5
Acta Trop. 2022 Nov 19. pii: S0001-706X(22)00462-4. [Epub ahead of print] 106771

Comparison of diurnal biting activity, life table, and demographic attributes of Aedes albopictus (asian tiger mosquito) from different urbanized settings in West Java, Indonesia.

Dimas Novianto, Upik Kesumawati Hadi, Susi Soviana, Huda Shalahudin Darusman.

  The Asian tiger mosquito, Aedes albopictus has well-adaptive behavior to environmental changes, including human urbanization, and has an essential role as the main vector of important pathogenic arboviruses. This study aims to analyze the biology and life table of the Ae. albopictus populations collected from urban and peri-urban areas of Bogor, West Java, Indonesia under laboratory conditions. Mosquito eggs collection was carried out in urban and peri-urban areas using ovitraps. The observation of the life table experiment that followed the development of Ae. albopictus started from the emergence of the first individual to the last surviving individual. Several biological parameters comparing Ae. albopictus from two collection sites based on life table analysis were shown to be significantly different. Biting activity of all mosquitoes from urban and peri-urban areas showed a clear bimodal activity with morning peak at 09:00-10.00 and evening peak at 16:00-17:00. Ae. albopictus from the urban area have higher fecundity, considerably longer lifespan, more gonotrophic cycles, and a higher net reproduction rate (R0) than Ae. albopictus from the peri-urban area. These findings will provide valuable information about the well-adapted Ae. albopictus in urban areas and assist in providing basic reproductive data to improve vector control and current surveillance strategies especially in the study area.

Keywords:  Aedes albopictus; life table; urbanization; vector-borne disease

DOI:  https://doi.org/10.1016/j.actatropica.2022.106771
Sci Rep. 2022 Nov 19. 12(1): 19946

An epidemiological model for mosquito host selection and temperature-dependent transmission of West Nile virus.

Augusto Fasano, Nicola Riccetti, Anastasia Angelou, Jaime Gomez-Ramirez, Federico Ferraccioli, Ioannis Kioutsioukis, Nikolaos I Stilianakis.

We extend a previously developed epidemiological model for West Nile virus (WNV) infection in humans in Greece, employing laboratory-confirmed WNV cases and mosquito-specific characteristics of transmission, such as host selection and temperature-dependent transmission of the virus. Host selection was defined by bird host selection and human host selection, the latter accounting only for the fraction of humans that develop symptoms after the virus is acquired. To model the role of temperature on virus transmission, we considered five temperature intervals (≤ 19.25 °C; > 19.25 and < 21.75 °C; ≥ 21.75 and < 24.25 °C; ≥ 24.25 and < 26.75 °C; and > 26.75 °C). The capacity of the new model to fit human cases and the week of first case occurrence was compared with the original model and showed improved performance. The model was also used to infer further quantities of interest, such as the force of infection for different temperatures as well as mosquito and bird abundances. Our results indicate that the inclusion of mosquito-specific characteristics in epidemiological models of mosquito-borne diseases leads to improved modelling capacity.

DOI: https://doi.org/10.1038/s41598-022-24527-5
Insects. 2022 Nov 18. pii: 1066. [Epub ahead of print]13(11):

Epidemiological, Entomological, and Climatological Investigation of the 2019 Dengue Fever Outbreak in Gewane District, Afar Region, North-East Ethiopia.

Wondemeneh Mekuriaw, Solomon Kinde, Bezabih Kindu, Yibeyin Mulualem, Girma Hailu, Araya Gebresilassie, Chalachw Sisay, Fitsum Bekele, Hiwot Amare, Mesfin Wossen, Adugna Woyessa, Chad L Cross, Louisa A Messenger.

  Dengue Fever (DF) is an important arthropod-borne viral infection that has repeatedly occurred as outbreaks in eastern and northeastern Ethiopia since 2013. A cross-sectional epidemiological outbreak investigation was carried out from September to November 2019 on febrile patients (confirmed malaria negative) who presented with suspected and confirmed DF at both public and private health facilities in Gewane District, Afar Region, northeastern Ethiopia. Entomological investigation of containers found in randomly selected houses belonging to DF-positive patients was undertaken to survey for the presence of Aedes larvae/pupae. A total of 1185 DF cases were recorded from six health facilities during the 3-month study period. The mean age of DF cases was 27.2 years, and 42.7% of cases were female. The most affected age group was 15-49 years old (78.98%). The total case proportions differed significantly across age groups when compared to the population distribution; there were approximately 15% and 5% higher case proportions among those aged 15-49 years and 49+ years, respectively. A total of 162 artificial containers were inspected from 62 houses, with 49.4% found positive for Aedes&nbsp;aegypti larva/pupae. Aedes mosquitoes were most commonly observed breeding in plastic tanks, tires, and plastic or metal buckets/bowls. World Health Organization entomological indices classified the study site as high risk for dengue virus outbreaks (House Index = 45.2%, Container Index = 49.4%, and Breteau Index = 129). Time series climate data, specifically rainfall, were found to be significantly predictive of AR (p = 0.035). Study findings highlight the importance of vector control to prevent future DF outbreaks in the region. The scarcity of drinking water and microclimatic conditions may have also contributed to the occurrence of this outbreak.

Keywords:  Aedes aegypti; Ethiopia; arbovirus; climate change; dengue fever; outbreak

DOI:  https://doi.org/10.3390/insects13111066
Pest Manag Sci. 2022 Nov 24.

Developing radiation-based sterile insect technique (SIT) for controlling Aedes aegypti: identification of a sterilizing dose.

Chao Chen, Robert L Aldridge, Seth Gibson, Jedidiah Kline, Vindhya Aryaprema, Whitney Qualls, Rui-de Xue, Leigh Boardman, Kenneth J Linthicum, Daniel A Hahn.

   BACKGROUND: The sterile insect technique (SIT) is emerging as a tool to supplement traditional pesticide-based control of Aedes aegypti, a prominent mosquito vector of microbes that have increased the global burden of human morbidity and mortality over the past 50 years. SIT relies on rearing, sterilizing, and releasing large numbers of male mosquitoes that will mate with fertile wild females, thus reducing production of offspring from the target population. In this study, we investigated the effects of ionizing radiation (gamma) on male and female survival, longevity, mating behavior, and sterility of Ae. aegypti in a dose-response design. This work is a first step towards developing an operational SIT field suppression program against Ae. aegypti in St. Augustine, Florida, USA.
RESULTS: Exposing late-stage pupae to 50 Gy of radiation yielded 99% male sterility while maintaining similar survival of pupae to adult emergence, adult longevity, and male mating competitiveness compared to unirradiated males. Females were completely sterilized at 30 Gy, and when females were dosed with 50 Gy, they had a lower incidence of blood feeding than unirradiated females.
CONCLUSION: Our work suggests that an ionizing radiation dose of 50 Gy should be used for future development of operational SIT in our program area because at this dose males are 99% sterile while maintaining mating competitiveness against unirradiated males. Furthermore, females that might be accidentally released with sterile males due to errors in sex sorting are also sterile and less likely to blood feed than unirradiated females at our 50 Gy dose.

Keywords:  Aedes aegypti; radiation; sterile insect technique; sterilizing dose

DOI:  https://doi.org/10.1002/ps.7303
Trop Med Infect Dis. 2022 Nov 12. pii: 372. [Epub ahead of print]7(11):

Field Evaluation of Novel Spatial Repellent Controlled Release Devices (CRDs) against Mosquitoes in an Outdoor Setting in the Northern Peruvian Amazon.

Carmen Flores-Mendoza, Victor M López-Sifuentes, Gissella M Vásquez, Craig A Stoops, Michael L Fisher, Ulrich R Bernier, Melynda Perry, Juan Mollica, Damián A Coltzau, Pablo Gurman, Sebastián D'hers, Noel M Elman.

  U.S. military troops are exposed to mosquito-borne pathogens when deployed to endemic regions. Personal protective measures such as permethrin-treated uniforms and dermal repellents are the cornerstones of mosquito-borne disease prevention for the U.S. military. These measures have limitations and additional personal protection tools, such as spatial repellent devices to decrease the risk of vector-borne pathogen transmission, are required. Novel spatial repellent controlled-release devices formulated with metofluthrin were evaluated in an outdoor setting in the northern Amazon of Peru to evaluate performance under field conditions. The metofluthrin emitting devices lowered the number of mosquitoes captured in protected human landing collections (HLC) compared to blank devices, although there were effect differences between Anopheles spp. and species in other mosquito genera. A computational-experimental model was developed to correlate HLC and active ingredient (AI) concentrations as a function of time and space. Results show a strong correlation between the released AI and the decrease in HLC. This model represents the first effort to obtain a predictive analytical tool on device performance using HLC as the entomological endpoint.

Keywords:  Anopheles; Peru; controlled release device; malaria; metofluthrin; mosquitoes; spatial repellent

DOI:  https://doi.org/10.3390/tropicalmed7110372
Am J Trop Med Hyg. 2022 Nov 21. pii: tpmd220481. [Epub ahead of print]

Phylogenetic Analysis of Wesselsbron Virus Isolated from Field-Captured Mosquitoes during a Rift Valley Fever Outbreak in Kabale District, Uganda-2016.

John T Kayiwa, Martin N Mayanja, Teddy Muwawu Nakayiki, Fred Senfuka, Julius Mugga, Jeffrey W Koehler, Eric C Mossel, Julius J Lutwama.

After confirmation of two human cases of Rift Valley fever (RVF) in March 2016 in the Kabale district of Uganda, an entomological investigation was conducted with a focus on mosquito species composition and abundance of known and potential mosquito vector species, and virus testing to identify species most likely involved in Rift Valley fever virus transmission. This information could be used to forecast risk and facilitate improvement of prevention and response tools for use in preventing or controlling future outbreaks. From these collections, two virus isolates were obtained, one each from a pool of Aedes tricholabis and Ae. gibbinsi. Next-generation sequencing identified both isolates as Wesselsbron virus, family Flaviviridae, a neglected arbovirus of economic importance. These are the first reported Wesselsbron virus isolates from Uganda since 1966.

DOI: https://doi.org/10.4269/ajtmh.22-0481
Trop Med Infect Dis. 2022 Nov 21. pii: 392. [Epub ahead of print]7(11):

Pattern of Aedes aegypti and Aedes albopictus Associated with Human Exposure to Dengue Virus in Kinshasa, the Democratic Republic of the Congo.

Kennedy Makola Mbanzulu, Roger Wumba, Leonard E G Mboera, Jean-Marie Ntumba Kayembe, Danoff Engbu, Michael Mondjo Bojabwa, Josué Kikana Zanga, Gerald Misinzo, Sharadhuli Iddi Kimera.

  Dengue is a worldwide public health concern. The current study assessed the extent of human exposure to the dengue virus in relation to the distribution pattern of Aedes aegypti and Ae. albopictus in Kinshasa. Cross-sectional surveys were carried out in 2021 and 2022. The baseline entomological survey involved 19 municipalities using a grid cell sampling approach. All containers holding water were inspected for the presence of larvae in each grid. The collected larvae were kept in an insectary until the adult emergence for morphological identification. Four hundred febrile patients attending the hospital were screened for the presence of dengue antibodies (IgG, IgM) and NS1 antigen using a rapid diagnostic test (RDT) Biosynex®. Residences of positive cases were geo-referenced. We evaluated 1850 grid cells, of which 19.5% were positive for Aedes larvae. The positive grid cells were identified in the Ndjili (44.0%), Mont Ngafula (32.0%) and Ngaliema (26.0%), and Limete (32.0%) municipalities. The Ae. aegypti (11.2%) predominated in the northwestern, and Ae. albopictus (9.1%) appeared in the high vegetation coverage areas. Of 61 (15.3%) participants exposed to dengue, 8.3% presented acute dengue. Young, (6-17 years), male, and Mont Amba district participants were most exposed to dengue. In conclusion, dengue occurrence in Kinshasa overlaps somewhat the geographical and ecological distributions of Ae. aegypti and Ae. albopictus. Both species are not homogenously distributed, likely due to environmental factors. These findings can assist the targeted control activities.

Keywords:  Aedes aegypti; Aedes albopictus; Kinshasa; Republic of the Congo; dengue; distribution; exposure

DOI:  https://doi.org/10.3390/tropicalmed7110392
Am J Trop Med Hyg. 2022 Nov 21. pii: tpmd211127. [Epub ahead of print]

Community Participation in Habitat Management and Larviciding for the Control of Malaria Vectors in Southern Malawi.

Steven Gowelo, Paola Meijer, Tinashe Tizifa, Tumaini Malenga, Monicah M Mburu, Alinune N Kabaghe, Dianne J Terlouw, Michèle van Vugt, Kamija S Phiri, Themba Mzilahowa, Constantianus J M Koenraadt, Henk van den Berg, Lucinda Manda-Taylor, Robert S McCann, Willem Takken.

Larval source management (LSM) could reduce malaria transmission when executed alongside core vector control strategies. Involving communities in LSM could increase intervention coverage, reduce operational costs, and promote sustainability via community buy-in. We assessed the effectiveness of community-led LSM to reduce anopheline larval densities in 26 villages along the perimeter of Majete Wildlife Reserve in southern Malawi. The communities formed LSM committees which coordinated LSM activities in their villages following specialized training. Effectiveness of larviciding by LSM committees was assessed via pre- and post-spray larval sampling. The effect of community-led LSM on anopheline larval densities in intervention villages was assessed via comparisons with densities in non-LSM villages over a period of 14 months. Surveys involving 502 respondents were undertaken in intervention villages to explore community motivation and participation, and factors influencing these outcomes. Larviciding by LSM committees reduced anopheline larval densities in post-spray sampling compared with pre-spray sampling (P < 0.0001). No differences were observed between anopheline larval densities during pre-spray sampling in LSM villages and those in non-LSM villages (P = 0.282). Knowledge about vector biology and control, and someone's role in LSM motivated community participation in the vector control program. Despite reducing anopheline larval densities in LSM villages, the impact of the community-led LSM could not be detected in our study setting because of low mosquito densities after scale-up of core malaria control interventions. Still, the contributions of the intervention in increasing a community's knowledge of malaria, its risk factors, and its control methods highlight potential benefits of the approach.

DOI: https://doi.org/10.4269/ajtmh.21-1127
Trop Med Infect Dis. 2022 Nov 21. pii: 391. [Epub ahead of print]7(11):

Malaria Vector Surveillance and Control in an Elimination Setting in South Africa.

Basil D Brooke.

  South Africa's malaria elimination plans are aligned to the World Health Organization's aim for a malaria-free world and include specific objectives within a specified time frame. These are proving difficult to achieve owing to the sporadic nature of locally acquired malaria in some affected districts, while other districts that were endemic for the disease are either malaria-free or very close to that goal. The WHO also specifies that continued measures to prevent the re-establishment of transmission are required in areas where elimination has been achieved. These measures include routine malaria vector surveillance in endemic districts that are free of malaria to assess receptivity and risk of reintroduction, which may prove difficult to justify in the face of competing public health priorities and limited resources. These issues are discussed here within the framework of vector surveillance and control and include recommendations on how they can be addressed going forward.

Keywords:  Anopheles; low-incidence settings; risk; vector control

DOI:  https://doi.org/10.3390/tropicalmed7110391
Diseases. 2022 Nov 20. pii: 109. [Epub ahead of print]10(4):

Exploring Potential Determinants of Mosquito Net Ownership and Use in Somalia: A Cross-Sectional Study.

Mitsuaki Hirai, Usman Umar, Patricia Darikwa, Ali Abdirahman Osman, Abdirahman Mohamed, Ahmed Mohamed Jama, Carolyn Masheti, Millhia Kader.

 In Somalia, malaria remains a major public health threat. Understanding what influences the ownership and use of mosquito nets is of vital importance to accelerate malaria prevention efforts in the country. To explore the potential determinants of mosquito net ownership and use, this study conducted a secondary data analysis of the Somalia Micronutrient Survey 2019. Survey participants were identified through the multi-stage stratified cluster sampling, and logistic regression was performed for bivariate and multivariate analysis. The results suggested that household head's age, educational attainment, household size, employment status of household members, socioeconomic status, geographic regions and type of residence are significantly associated with mosquito net ownership (p < 0.05). The analysis also highlighted household head's age as an influential factor to mosquito net use. By further exploring and understanding the psychosocial determinants of mosquito net ownership and use, malaria prevention interventions can be made more effective in Somalia.

Keywords: malaria; mosquito; prevention; public health

DOI: https://doi.org/10.3390/diseases10040109
Travel Med Infect Dis. 2022 Nov 22. pii: S1477-8939(22)00251-4. [Epub ahead of print] 102505

Retrospective spatiotemporal analysis of malaria cases reported between 2000 and 2020 in North Carolina, USA.

Felix Zowonoo, Guy Iverson, Michael Doyle, Stephanie L Richards.

   BACKGROUND: There are 1,000-2,000 cases of malaria diagnosed in the United States annually and most are imported.
METHODS: Malaria cases reported between 2000-2020 in North Carolina (NC) were analyzed (NC Department of Health and Human Services, Division of Public Health). Differences in numbers of NC malaria cases were further analyzed by year, month, county, gender, age, and country of origin.
RESULTS: Most cases originated from travelers visiting Africa and returning to NC (i.e., Mecklenburg [N = 162 cases], Wake [N = 153], Guilford [N = 103], Durham [N = 74], and Cumberland [N = 41] Counties). Per capita analysis (i.e., per 100,000 population) was used to correct for differences in NC county population sizes and Durham (N = 22.8), Guilford (N = 19.0), Onslow (N = 14.7), Mecklenburg (N = 14.5), Wake (N = 13.5), Orange (N = 12.8) and Cumberland (N = 12.2) Counties showed the highest cases. Malaria was more prevalent among males (N = 532) relative to females (N = 245), and this difference was statistically significant.
CONCLUSIONS: Travelers visiting malaria-endemic regions should be educated on malaria prevention measures (e.g., chemoprophylaxis, mosquito repellent). These measures should be readily available to travelers. The malaria registry in NC should be improved by requiring additional data related to imported malaria cases.

Keywords:  Malaria prevention; Travel; Vector-borne disease

DOI:  https://doi.org/10.1016/j.tmaid.2022.102505
Arch Med Res. 2022 Nov;pii: S0188-4409(22)00126-6. [Epub ahead of print]53(7): 649-657

Yellow Fever: A Perennial Threat.

Jose Tuells, Andrés F Henao-Martínez, Carlos Franco-Paredes.

  Despite the availability of a safe and effective vaccine, yellow fever remains a major vaccine-preventable disease in endemic regions. Additionally, travelers risk acquiring yellow fever when visiting areas of endemic transmission or locations with ongoing outbreaks. Yellow fever is a viral hemorrhagic fever that has inflicted stigma, illness, and death among human societies. From the 17th to the 19th centuries, yellow fever remained a mysterious illness that predominantly affected tropical regions in Africa, the Caribbean and the Americas. The disease was as feared as cholera or smallpox, and played a significant geopolitical role in shaping modern societies. Epidemics of yellow fever brought out the best and the worst of human nature: the disease spread to new regions during the Atlantic slave trade; while the identification of its causative viral agent and mode of transmission, as well as the development of a vaccine, were made possible by the sacrifice of selfless scientists. Confirmation of the vector transmission of YF paved the way for the development of an effective vaccine in the first half of the 20th century. Encroachment of human settlements into locations with sylvatic transmission has blurred the distinction between the urban and sylvatic cycles. Introduction or expansion of routine immunization activities and reaching hard-to-reach populations consitute public health priorities toward ensuring vaccine equity in endemic areas. It is also critical to ensure the timely immunization of at-risk populations during outbreaks and to promote vaccination of international travelers. We conclude that the threat of YF will linger far into the 21st century as a leading public health emergency of global concern under the International Health Regulations.

Keywords:  Aedes aegypti; Aedes albopictus; Hemagogus; Vaccine; Vaccine-preventable diseases; Yellow fever

DOI:  https://doi.org/10.1016/j.arcmed.2022.10.005
Afr Health Sci. 2022 Jun;22(2): 194-203

Assessment of knowledge of malaria and its control practices in mining and sugarcane growing regions of Western Kenya highlands.

Davis Kipcho Mukabane, Nicholas Kitungulu, Philip A Ogutu, Jackson Cheruiyot Korir, David Hughes Mulama.

   Background: Despite upscaled control efforts, deaths and hospitalization due to malaria remained high in counties of western Kenya highlands.
Objectives: This study assessed the knowledge of malaria in two rural communities, the control strategies they use, and their capacity to integrate the available control programs.
Methods: A cross-sectional survey was carried out in two rural villages in November - December 2018. Focus group discussions and a questionnaire survey were carried out in 736 households. Frequencies and proportions were used for descriptive analysis while the Chi-square test was used to determine factors that were associated with knowledge of malaria at p ≤ 0.05.
Results: Ninety-seven percent of the respondents had knowledge of malaria and this was associated with the level of education attained (χ2 = 30.108; p > 0.0001). Bed net ownership was at 86% and 92% correctly identified its use. Draining stagnant water (53.9%) was the most cited environmental management practice.
Conclusion: There was awareness of the risk factors of malaria transmission in the study sites. The local communities must be mobilized and empowered through EIC for the control practises to bear fruit against malaria transmission. However, more sensitization needs to be done to optimize the use of malaria control practices.

Keywords:  Kenya highlands; Malaria; Mining; control practices

DOI:  https://doi.org/10.4314/ahs.v22i2.23
Biology (Basel). 2022 Nov 13. pii: 1658. [Epub ahead of print]11(11):

Entomopathogenic Nematodes and Their Symbiotic Bacteria from the National Parks of Thailand and Larvicidal Property of Symbiotic Bacteria against Aedes aegypti and Culex quinquefasciatus.

Aunchalee Thanwisai, Paramaporn Muangpat, Wipanee Meesil, Pichamon Janthu, Abdulhakam Dumidae, Chanakan Subkrasae, Jiranun Ardpairin, Sarunporn Tandhavanant, Timothy P Yoshino, Apichat Vitta.

  Entomopathogenic nematodes (EPNs) are insect parasitic nematodes of the genera Het-erorhabditis and Steinernema. These nematodes are symbiotically associated with the bacteria, Photorhabdus and Xenorhabdus, respectively. National parks in Thailand are a potentially rich resource for recovering native EPNs and their symbiotic bacteria. The objectives of this study are to isolate and identify EPNs and their bacterial flora from soil samples in four national parks in Thailand and to evaluate their efficacy for controlling mosquito larvae. Using a baiting method with a Galleria mellonella moth larvae and a White trap technique, 80 out of 840 soil samples (9.5%) from 168 field sites were positive for EPNs. Sequencing of an internal transcribed spacer resulted in the molecular identification of Heterorhabditis nematode isolates as H. indica, H. baujardi and Heterorhabditis SGmg3, while using 28S rDNA sequencing, Steinernema nematode species were identified as S. guang-dongense, S. surkhetense, S. minutum, S. longicaudum and one closely related to S. yirgalemense. For the symbiotic bacterial isolates, based on recA sequencing, the Photorhabdus spp. were identified as P. luminescens subsp. akhurstii, P. luminescens subsp. hainanensis and P. luminescens subsp. australis. Xenorhabdus isolates were identified as X. stockiae, X. indica, X. griffiniae, X. japonica and X. hominickii. Results of bioassays demonstrate that Photorhabdus isolates were effective on both Aedes aegypti and Culex quinquefasciatus. Therefore, we conclude that soil from Thailand's national parks contain a high diversity of entomopathogenic nematodes and their symbiotic bacteria. Photorhabdus bacteria are larvicidal against culicine mosquitoes and may serve as effective biocontrol agents.

Keywords:  Aedes; Culex; Photorhabdus; Xenorhabdus; bioassay; entomopathogenic nematode

DOI:  https://doi.org/10.3390/biology11111658
Pak J Biol Sci. 2022 Sep;25(10): 911-921

Mosquito Larvicides of Partial and Combinations Extract of Ethnobotanical Plant from North Sulawesi, Indonesia.

Carolin Manuahe, Mokosuli Yermia Semuel, Ellen Hettie Adil, Orbanus Naharia.

 Background and Objective: Diseases caused by microbes vectored by mosquitoes are still a health problem in tropical countries today. DHF and Malaria are the two primary diseases vectored by mosquitoes, the morbidity and mortality rates have increased in low countries until now. However, the best way to control these two diseases is to control vectors, namely mosquitoes. Research has been conducted to determine the bioactive content and larvicidal activity of local plant extracts of North Sulawesi. Materials and Methods: The clove and trumpet flower samples were obtained from Minahasa, while the nutmeg samples were obtained from Sitaro Regency. Empirically, people use plant parts to repel mosquitoes. Extraction of plant simplicia was carried out by the maceration method. Qualitative and quantitative methods carried out the phytochemical content analysis. Qualitative analysis uses Harborne's (1996) method while qualitative analysis uses the UV Vis Spectrophotometer method. Toxicity tests were carried out on mosquito larvae developed in the laboratory. Results: The results showed that combining clove leaf extract, nutmeg flesh extract and trumpet flower synergistically increased the bioactive content. Flavonoids increased in the combination of extracts compared to partial extracts. The combination of extracts showed the highest toxicity to mosquito larvae (LC50: 22.541 mg L1), while the lowest was the partial extract of clove leaves with LC50 (54.965 mg L1). Conclusion: The combination of extracts showed the best toxicity activity on mosquito larvae. Research on bioactive characteristics and toxicity in adult mosquitoes needs to be carried out in the future.

Keywords: Clove leaf; extract; larvicides; mortality; nutmeg flesh; toxicity; trumpet flower

DOI: https://doi.org/10.3923/pjbs.2022.911.921
PLoS Negl Trop Dis. 2022 Nov 22. 16(11): e0010954

RNAi-mediated knockdown of arginine kinase genes leads to high mortality and negatively affect reproduction and blood-feeding behavior of Culex pipiens pallens.

Kun Qian, Qingqing Guan, Haoyu Zhang, Nan Zhang, Xiangkun Meng, Hongxia Liu, Jianjun Wang.

BACKGROUND: Arginine kinase (AK) is one of the crucial enzymes involved in energy metabolism in invertebrates, and has been proposed as the target for RNA interference (RNAi)-based control of agricultural insect pests. While there is only one AK gene in most insects, two AK genes were identified in Culex pipiens pallens, the primary vector of lymphatic filariasis and epidemic encephalitis.
METHODS: The full-length cDNA sequences of CpAK1 and CpAK2 genes were obtained by reverse transcription PCR(RT-PCR) and rapid amplification of cDNA ends (RACE). The expression levels of CpAK1 and CpAK2 in different developmental stages and tissues were detected by reverse transcription quantitative PCR (RT-qPCR). The role of CpAK1 and CpAK2 in the reproduction and blood feeding behavior was analyzed using RNA interference (RNAi).
RESULTS: Full-length cDNAs of CpAK1 and CpAK2 were isolated from Cx. pipiens pallens. Analysis of the expression pattern revealed that the mRNA level of CpAK1 was significantly higher than CpAK2 in all development stages and tissues examined, and the expressions of both CpAK1 and CpAK2 were upregulated in response to blood feeding. The co-knockdown of CpAK1 and CpAK2 mediated by RNAi led to high mortality (74.3%) of adult female mosquitoes and decreased hatchability (59.9%). Remarkably, the blood feeding rate and the engorgement rate of the female mosquitoes were negatively affected by co-injection of dsRNAs targeting CpAK1 and CpAK2.
CONCLUSION: CpAK1 and CpAK2 were detected in all developmental stages and tissues, but showed divergence in expression level. RNAi-mediated knockdown of AK genes leads to high mortality and negatively affect blood-feeding behavior of Cx. pipiens pallens, suggesting that AK could be used for the target of RNAi-based mosquito control in the future.

DOI: https://doi.org/10.1371/journal.pntd.0010954
Curr Infect Dis Rep. 2022 Nov 17. 1-12

Chikungunya: An Emerging Public Health Concern.

Omar Mourad, Leila Makhani, Lin H Chen.

   Purpose of Review: The worldwide spread of chikungunya over the past two decades calls for greater knowledge and awareness of the virus, its route of transmission, methods of diagnosis, and the use of available treatment and prevention measures.
Recent Findings: Chikungunya virus infection, an Aedes mosquito-borne febrile disease, has spread from Africa and Asia to Europe and the Americas and from the tropics and subtropics to temperate regions. International travel is a pivotal influence in the emergence of chikungunya as a global public health threat, as evidenced by a growing number of published reports on travel-related chikungunya infections. The striking features of chikungunya are arthralgia and arthritis, and the disease is often mistaken for dengue. Although mortality is low, morbidity can be profound and persistent. Current treatment for chikungunya is supportive; chikungunya vaccines and therapeutics are in development. Travelers planning to visit areas where the mosquito vectors are present should be advised on preventive measures.
Summary: Chikungunya is an emerging disease in the Americas. Frequent travel, the presence of at least two competent mosquito species, and a largely naïve human population in the Western Hemisphere create a setting conducive to future outbreaks. Awareness of the disease and its manifestations is critical to effectively and safely manage and limit its impact. Vaccines in late-stage clinical trials offer a new pathway to prevention.

Keywords:  Alphavirus; Arbovirus; Arthritis; Importation; Infectious diseases; Travel; Vector-borne disease

DOI:  https://doi.org/10.1007/s11908-022-00789-y