bims-mosdis 2022-01-02 papers

bims-mosdis

Biomed News

on Mosquito distribution and disease

Issue of 2022–01–02
twenty-two papers selected by
Richard Halfpenny, Staffordshire University

Vector Competence of the Invasive Mosquito Species Aedes koreicus for Arboviruses and Interference with a Novel Insect Specific Virus.
First Evidence of West Nile Virus Overwintering in Mosquitoes in Germany.
Perceived Risk of Mosquito-Borne Arboviruses in the Continental United States.
Mosquito Communities Vary across Landscape and Vertical Strata in Indian River County, Florida.
Current Situation of Malaria and Resistance of Main Vectors to WHO Recommended Insecticides in an Endemic Area, Southeastern Iran.
Prevention and control of dengue and Chikungunya in Colombia: A cost-effectiveness analysis.
Plasmodium falciparum and Plasmodium vivax Adjust Investment in Transmission in Response to Change in Transmission Intensity: A Review of the Current State of Research.
Multiple insecticide resistance mechanisms in urban population of Anopheles coluzzii (Diptera: Culicidae) from Lagos, South-West Nigeria.
Vector Specificity of Arbovirus Transmission.
Towards Integrated Management of Dengue in Mumbai.
The Potential for a Released Autosomal X-Shredder Becoming a Driving-Y Chromosome and Invasively Suppressing Wild Populations of Malaria Mosquitoes.
Extracts of Amazonian Fungi With Larvicidal Activities Against Aedes aegypti.
Zika Virus Overview: Transmission, Origin, Pathogenesis, Animal Model and Diagnosis.
Case Report: Neurologic Presentation of West Nile Virus: Difficult Diagnosis.
West Nile Virus Vaccination Protects against Usutu Virus Disease in Mice.
Risk Factors Associated with a Dengue Fever Outbreak in Islamabad, Pakistan: Case-Control Study.
Detrimental effects of a failed infection by a co-invasive parasite on a native congeneric parasite and its native host.
mRNA Vaccine Protects against Zika Virus.
Transposable element variants and their potential adaptive impact in urban populations of the malaria vector Anopheles coluzzii.
The Trend of Malaria Cases, Positivity Rate, and Determinant Factors in the Amhara Regional State, Ethiopia: A Mixed Method.
Eliminating malaria in conflict zones: public health strategies developed in the Sri Lanka Civil War.
Erratum: "The Complex Epidemiologic Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review".

Viruses. 2021 Dec 14. pii: 2507. [Epub ahead of print]13(12):

Vector Competence of the Invasive Mosquito Species Aedes koreicus for Arboviruses and Interference with a Novel Insect Specific Virus.

Stephanie Jansen, Dániel Cadar, Renke Lühken, Wolf Peter Pfitzner, Hanna Jöst, Sandra Oerther, Michelle Helms, Branka Zibrat, Konstantin Kliemke, Norbert Becker, Olli Vapalahti, Giada Rossini, Anna Heitmann.

  The global spread of invasive mosquito species increases arbovirus infections. In addition to the invasive species Aedes albopictus and Aedes japonicus, Aedes koreicus has spread within Central Europe. Extensive information on its vector competence is missing. Ae. koreicus from Germany were investigated for their vector competence for chikungunya virus (CHIKV), Zika virus (ZIKV) and West Nile virus (WNV). Experiments were performed under different climate conditions (27 ± 5 °C; 24 ± 5 °C) for fourteen days. Ae. koreicus had the potential to transmit CHIKV and ZIKV but not WNV. Transmission was exclusively observed at the higher temperature, and transmission efficiency was rather low, at 4.6% (CHIKV) or 4.7% (ZIKV). Using a whole virome analysis, a novel mosquito-associated virus, designated Wiesbaden virus (WBDV), was identified in Ae. koreicus. Linking the WBDV infection status of single specimens to their transmission capability for the arboviruses revealed no influence on ZIKV transmission. In contrast, a coinfection of WBDV and CHIKV likely has a boost effect on CHIKV transmission. Due to its current distribution, the risk of arbovirus transmission by Ae. koreicus in Europe is rather low but might gain importance, especially in regions with higher temperatures. The impact of WBDV on arbovirus transmission should be analyzed in more detail.

Keywords:  Aedes koreicus; Wiesbaden virus; arbovirus transmission; insect specific virus; invasive mosquito species; vector competence

DOI:  https://doi.org/10.3390/v13122507
Viruses. 2021 Dec 09. pii: 2463. [Epub ahead of print]13(12):

First Evidence of West Nile Virus Overwintering in Mosquitoes in Germany.

Helge Kampen, Birke Andrea Tews, Doreen Werner.

  Mosquitoes collected from mid-December 2020 to early March 2021 from hibernacula in northeastern Germany, a region of West Nile virus (WNV) activity since 2018, were examined for WNV-RNA. Among the 6101 mosquitoes tested in 722 pools of up to 12 specimens, one pool of 10 Culex pipiens complex mosquitoes collected in early March 2021 in the cellar of a medieval castle in Rosslau, federal state of Saxony-Anhalt, tested positive. Subsequent mosquito DNA analysis produced Culex pipiens biotype pipiens. The pool homogenate remaining after nucleic acid extraction failed to grow the virus on Vero and C6/36 cells. Sequencing of the viral NS2B-NS3 coding region, however, demonstrated high homology with virus strains previously collected in Germany, e.g., from humans, birds, and mosquitoes, which have been designated the East German WNV clade. The finding confirms the expectation that WNV can overwinter in mosquitoes in Germany, facilitating an early start to the natural transmission season in the subsequent year. On the other hand, the calculated low infection prevalence of 0.016-0.20%, depending on whether one or twelve of the mosquitoes in the positive pool was/were infected, indicates a slow epidemic progress and mirrors the still-hypoendemic situation in Germany. In any case, local overwintering of the virus in mosquitoes suggests its long-term persistence and an enduring public health issue.

Keywords:  Culex pipiens; Germany; West Nile virus; first report; mosquito vectors; overwintering; transmission

DOI:  https://doi.org/10.3390/v13122463
Pathogens. 2021 Nov 30. pii: 1562. [Epub ahead of print]10(12):

Perceived Risk of Mosquito-Borne Arboviruses in the Continental United States.

Saul Lozano, Jonathan Day, Lilyana Ortega, Maggie Silver, Roxanne Connelly.

  The United States experienced local transmission of West Nile Virus (WNV) for the first time in 1999, and Zika Virus (ZIKV) in 2016. These introductions captured the public's attention in varying degrees. The research presented here analyzes the disproportional perception of ZIKV risk compared to WNV transmission risk, by the public and vector control personnel. The risk perception of vector control was measured through purposive sampled interviews (24 interviews in 13 states; May 2020-June 2021), while the public's perception was estimated from news publications (January 2000-December 2020), and Google searches (January 2004-December 2020). Over time, we observed a decrease in the frequency of press reporting and Google searches of both viruses with decreasing annual peaks in the summer. The highest peak of ZIKV news, and searches, surpassed that of WNV. We observed clear differences in the contents of the headlines for both viruses. We propose that the main reason in risk perception differences between the viruses were psychological. Zika infections (mosquito-borne and sexually transmitted) can result in devastating symptoms in fetuses and newborns, observations that frequently appeared in ZIKV-related headlines. Our results highlight the likely influence the news media has on risk perception and the need for public health agencies to play active roles in the conversation, helping disseminate timely and accurate information. Understanding the factors that shape risk perceptions of vector-borne diseases will hopefully lead to better use of resources by providing better guidance.

Keywords:  West Nile Virus; Zika Virus; risk perception; vector-borne diseases

DOI:  https://doi.org/10.3390/pathogens10121562
Pathogens. 2021 Dec 03. pii: 1575. [Epub ahead of print]10(12):

Mosquito Communities Vary across Landscape and Vertical Strata in Indian River County, Florida.

Bryan V Giordano, Anthony Cruz, Daniel W Pérez-Ramos, Martina M Ramos, Yasmin Tavares, Eric P Caragata.

  Mosquito and arbovirus surveillance is essential to the protection of public health. A majority of surveys are undertaken at ground level. However, mosquitoes shelter, breed, and quest for hosts across vertical strata, thus limiting our ability to fully describe mosquito and arboviral communities. To elucidate patterns of mosquito vertical stratification, canopy traps were constructed to sample mosquitoes at heights of 1.5, 5.0, and 8.7 m across three different landscape types in a Florida coastal conservation area. We assessed trapping efforts using individual-based rarefaction and extrapolation. The effects of height, landscape, site location, and sampling date on mosquito community composition were parsed out using permutational ANOVA on a Hellinger-transformed Bray-Curtis dissimilarity abundance matrix. Lastly, a generalized linear mixed effects model (GLMM) was used to explore species-specific vertical patterns. We observed differences in sampling effort and community composition structure across various heights and landscapes. Our GLMM revealed significant effects of trap height for Aedes taeniorhynchus, Anopheles crucians, Anopheles quadrimaculatus, and Culex coronator, but not for Culex nigripalpus, the ultra-dominant species present in this area. Together these data provide evidence that height and landscape significantly affect mosquito community structures and highlight a need to develop sampling regimes to target specific vector and nuisance species at their preferred height and across different landscape types.

Keywords:  GLMM; canopy; mosquito; stratification; vector

DOI:  https://doi.org/10.3390/pathogens10121575
J Med Entomol. 2021 Dec 27. pii: tjab214. [Epub ahead of print]

Current Situation of Malaria and Resistance of Main Vectors to WHO Recommended Insecticides in an Endemic Area, Southeastern Iran.

Nasrollah Saberi, Ahmad Raeisi, Mohammad Amin Gorouhi, Hassan Vatandoost, Minoo Mashayekhi, Fatemeh Nikpour, Faramarz Bozorg Omid, Abbas Rahimi Foroushani, Ahmad Ali Hanafi-Bojd.

  Although malaria is endemic in some areas of southeastern Iran, following the successful national malaria elimination plan, the local transmission area has been shrunk. The main cases in Iran are due to Plasmodium vivax followed by P. falciparum. This study was aimed to determine the current situation of malaria in Kerman Province of Iran and evaluate the insecticide resistance of main vectors. The field study was conducted in 2019. Data of new malaria cases were obtained from the health centers for the period of 2009-2018. Susceptibility status of Anopheles stephensi and An. dthali was evaluated against dichlorodiphenyltrichloroethane, Dieldrin, Malathion, Bendiocarb, Deltamethrin, and Temephos at the diagnostic dose. A total of 522 malaria cases were recorded and divided into indigenous (33.14%) and imported (66.86%) categories. The highest incidence of the disease was reported from the southern areas of the province, where all indigenous cases occurred. Adults of An. stephensi were resistant to dichlorodiphenyltrichloroethane while its resistance to be confirmed to dieldrin, bendiocarb and deltamethrin. As An. dthali had less than 98% mortality against bendiocarb, the resistance status should be confirmed with more tests. Our findings showed both species had less than 98% mortality against bendiocarb and deltamethrin insecticides which are used in malaria vector control program in Iran. Due to the susceptibility of these vectors to temephos, larviciding can be advised for vector control in this area.

Keywords:   Anopheles dthali ; Anopheles stephensi ; insecticide resistance; malaria

DOI:  https://doi.org/10.1093/jme/tjab214
PLoS Negl Trop Dis. 2021 Dec 29. 15(12): e0010086

Prevention and control of dengue and Chikungunya in Colombia: A cost-effectiveness analysis.

Anneke L Claypool, Margaret L Brandeau, Jeremy D Goldhaber-Fiebert.

BACKGROUND: Chikungunya and dengue are emerging diseases that have caused large outbreaks in various regions of the world. Both are both spread by Aedes aegypti and Aedes albopictus mosquitos. We developed a dynamic transmission model of chikungunya and dengue, calibrated to data from Colombia (June 2014 -December 2017).
METHODOLOGY/PRINCIPAL FINDINGS: We evaluated the health benefits and cost-effectiveness of residual insecticide treatment, long-lasting insecticide-treated nets, routine dengue vaccination for children aged 9, catchup vaccination for individuals aged 10-19 or 10-29, and portfolios of these interventions. Model calibration resulted in 300 realistic transmission parameters sets that produced close matches to disease-specific incidence and deaths. Insecticide was the preferred intervention and was cost-effective. Insecticide averted an estimated 95 chikungunya cases and 114 dengue cases per 100,000 people, 61 deaths, and 4,523 disability-adjusted life years (DALYs). In sensitivity analysis, strategies that included dengue vaccination were cost-effective only when the vaccine cost was 14% of the current price.
CONCLUSIONS/SIGNIFICANCE: Insecticide to prevent chikungunya and dengue in Columbia could generate significant health benefits and be cost-effective. Because of limits on diagnostic accuracy and vaccine efficacy, the cost of dengue testing and vaccination must decrease dramatically for such vaccination to be cost-effective in Colombia. The vectors for chikungunya and dengue have recently spread to new regions, highlighting the importance of understanding the effectiveness and cost-effectiveness of policies aimed at preventing these diseases.

DOI: https://doi.org/10.1371/journal.pntd.0010086
Front Cell Infect Microbiol. 2021 ;11 786317

Plasmodium falciparum and Plasmodium vivax Adjust Investment in Transmission in Response to Change in Transmission Intensity: A Review of the Current State of Research.

Colins O Oduma, Cristian Koepfli.

  Malaria parasites can adjust the proportion of parasites that develop into gametocytes, and thus the probability for human-to-vector transmission, through changes in the gametocyte conversion rate. Understanding the factors that impact the commitment of malaria parasites to transmission is required to design better control interventions. Plasmodium spp. persist across countries with vast differences in transmission intensities, and in sites where transmission is highly seasonal. Mounting evidence shows that Plasmodium spp. adjusts the investment in transmission according to seasonality of vector abundance, and transmission intensity. Various techniques to determine the investment in transmission are available, i.e., short-term culture, where the conversion rate can be measured most directly, genome and transcriptome studies, quantification of mature gametocytes, and mosquito feeding assays. In sites with seasonal transmission, the proportion of gametocytes, their densities and infectivity are higher during the wet season, when vectors are plentiful. When countries with pronounced differences in transmission intensity were compared, the investment in transmission was higher when transmission was low, thus maximizing the parasite's chances to be transmitted to mosquitoes. Increased transmissibility of residual infections after a successful reduction of malaria transmission levels need to be considered when designing intervention measures.

Keywords:  Plasmodium falciparum (Pf); Plasmodium vivax (pv); gametocyte carriage; investment in transmission; seasonality; transmission intensity

DOI:  https://doi.org/10.3389/fcimb.2021.786317
Acta Trop. 2021 Dec 24. pii: S0001-706X(21)00469-1. [Epub ahead of print] 106291

Multiple insecticide resistance mechanisms in urban population of Anopheles coluzzii (Diptera: Culicidae) from Lagos, South-West Nigeria.

Omotayo Ahmed Idowu, Ande Adeolu Taiwo, Oduola Adedayo Olatunbosun, Adelaja Olukayode, Adesalu Oluwakemi, Jimoh Tawakalitu Romoke, Ghazali Abdullahi Idowu, Awolola Samson Taiwo.

  Malaria is a major public health challenge in Africa with Nigeria accounting for the highest burden of the disease in the world. Vector control has proved to be a highly effective component of malaria control, however, the development and spread of insecticide resistance in major vectors of malaria have been a major challenge. This study assessed resistance mechanisms in Anopheles coluzzii populations from Kosofe, Lagos mainland and Ojo Local Government Areas in Lagos, Nigeria where An. gambiae s.l is resistant to DDT and Permethrin. WHO susceptibility bioassay test was used in determining resistance status of An. coluzzii to discriminating doses of DDT and Permethrin while synergist assay was used to assess the involvement of monooxygenases in resistance development. Sub-species of An. gambiae s.l (An. gambiae and An. coluzzii) were identified using polymerase chain reaction (PCR) and Restriction Fragment Length Polymorphism (PCR-RFLP) while Allele-Specific Polymerase Chain Reaction (AS-PCR) assay was used to detect knockdown mutation (kdr-West; L1014F). Biochemical assays were used in determining the activities of metabolic enzymes. High DDT resistance was recorded in An. coluzzii populations from the three sites. Mortality rate of mosquitoes exposed confirmed Permethrin resistance in Kosofe (50%) and Lagos mainland (48%) but resistance was suspected in Ojo (96%). All specimens tested were confirmed as An. coluzzii with low kdr frequency; 11.6%, 16.4% and 6.7% in Kosofe, Lagos mainland and Ojo respectively. Pre-exposure to synergist; PBO before exposure to Permethrin led to increased mortality in all populations. Esterase activity was insignificantly overexpressed in Kosofe (p = 0.849) and Lagos mainland (p = 0.229) populations. In contrast, GST activity was significantly lower in populations from Lagos mainland (63.650 ± 9.861; p = 0.007) and Ojo (91.765 ± 4.959; p = 0.042) than Kisumu susceptible strains (120.250 ± 13.972). Monooxygenase activity was higher in Lagos mainland (2.371 ± 0.261) and Ojo (1.361 ± 0.067) populations, albeit significantly in Lagos mainland (p = 0.007) only. Presence of target-site mutation in all populations, increased mortality with pre-exposure to PBO and elevated monooxygenase in Lagos mainland were confirmed. Multiple resistance mechanisms in some urban populations of An. coluzzii from Lagos, Nigeria calls for appropriate resistance management strategies.

Keywords:  Anopheles coluzzii; DDT; Esterase; Glutathione-S-Transferase; Knockdown mutation (kdr); Monooxygenase; Permethrin; Piperonyl butoxide; insecticide resistance

DOI:  https://doi.org/10.1016/j.actatropica.2021.106291
Front Microbiol. 2021 ;12 773211

Vector Specificity of Arbovirus Transmission.

Marine Viglietta, Rachel Bellone, Adrien Albert Blisnick, Anna-Bella Failloux.

  More than 25% of human infectious diseases are vector-borne diseases (VBDs). These diseases, caused by pathogens shared between animals and humans, are a growing threat to global health with more than 2.5 million annual deaths. Mosquitoes and ticks are the main vectors of arboviruses including flaviviruses, which greatly affect humans. However, all tick or mosquito species are not able to transmit all viruses, suggesting important molecular mechanisms regulating viral infection, dissemination, and transmission by vectors. Despite the large distribution of arthropods (mosquitoes and ticks) and arboviruses, only a few pairings of arthropods (family, genus, and population) and viruses (family, genus, and genotype) successfully transmit. Here, we review the factors that might limit pathogen transmission: internal (vector genetics, immune responses, microbiome including insect-specific viruses, and coinfections) and external, either biotic (adult and larvae nutrition) or abiotic (temperature, chemicals, and altitude). This review will demonstrate the dynamic nature and complexity of virus-vector interactions to help in designing appropriate practices in surveillance and prevention to reduce VBD threats.

Keywords:  arbovirus; host–pathogen interactions; mosquito; tick; vectorial transmission

DOI:  https://doi.org/10.3389/fmicb.2021.773211
Viruses. 2021 Dec 04. pii: 2436. [Epub ahead of print]13(12):

Towards Integrated Management of Dengue in Mumbai.

Prasad N Paradkar, Pallavi R Sahasrabudhe, Mrunal Ghag Sawant, Sandeepan Mukherjee, Kim R Blasdell.

  With increasing urbanisation, the dengue disease burden is on the rise in India, especially in large cities such as Mumbai. Current dengue surveillance in Mumbai includes municipal corporation carrying out specific activities to reduce mosquito breeding sites and the use of insecticides to suppress the adult mosquito populations. Clinical cases remain either underreported or misreported due to the restriction to government clinics, missing the large private health care sector. There is a need for an integrated approach to manage dengue outbreaks in Mumbai. There are various novel strategies available for use that can be utilised to improve disease detection, mosquito surveillance, and control of mosquito-borne diseases. These novel technologies are discussed in this manuscript. Given the complex ecosystem of mosquito-borne diseases in Mumbai, integrating data obtained from these technologies would support the ongoing mosquito control measures in Mumbai.

Keywords:  India; Mumbai; Wolbachia; dengue; disease surveillance; mosquito; novel strategies

DOI:  https://doi.org/10.3390/v13122436
Front Bioeng Biotechnol. 2021 ;9 752253

The Potential for a Released Autosomal X-Shredder Becoming a Driving-Y Chromosome and Invasively Suppressing Wild Populations of Malaria Mosquitoes.

Yehonatan Alcalay, Silke Fuchs, Roberto Galizi, Federica Bernardini, Roya Elaine Haghighat-Khah, Douglas B Rusch, Jeffrey R Adrion, Matthew W Hahn, Pablo Tortosa, Rachel Rotenberry, Philippos Aris Papathanos.

  Sex-ratio distorters based on X-chromosome shredding are more efficient than sterile male releases for population suppression. X-shredding is a form of sex distortion that skews spermatogenesis of XY males towards the preferential transmission of Y-bearing gametes, resulting in a higher fraction of sons than daughters. Strains harboring X-shredders on autosomes were first developed in the malaria mosquito Anopheles gambiae, resulting in strong sex-ratio distortion. Since autosomal X-shredders are transmitted in a Mendelian fashion and can be selected against, their frequency in the population declines once releases are halted. However, unintended transfer of X-shredders to the Y-chromosome could produce an invasive meiotic drive element, that benefits from its biased transmission to the predominant male-biased offspring and its effective shielding from female negative selection. Indeed, linkage to the Y-chromosome of an active X-shredder instigated the development of the nuclease-based X-shredding system. Here, we analyze mechanisms whereby an autosomal X-shredder could become unintentionally Y-linked after release by evaluating the stability of an established X-shredder strain that is being considered for release, exploring its potential for remobilization in laboratory and wild-type genomes of An. gambiae and provide data regarding expression on the mosquito Y-chromosome. Our data suggest that an invasive X-shredder resulting from a post-release movement of such autosomal transgenes onto the Y-chromosome is unlikely.

Keywords:  gene drive; genetic control; malaria; risk assessment; sex-ratio distortion

DOI:  https://doi.org/10.3389/fbioe.2021.752253
Front Microbiol. 2021 ;12 743246

Extracts of Amazonian Fungi With Larvicidal Activities Against Aedes aegypti.

Marta Rodrigues de Oliveira, Ricardo de Melo Katak, Gilvan Ferreira da Silva, Osvaldo Marinotti, Olle Terenius, Wanderli Pedro Tadei, Afonso Duarte Leão de Souza, Antonia Queiroz Lima de Souza.

  The global increase in diseases transmitted by the vector Aedes aegypti, new and re-emerging, underscores the need for alternative and more effective methods of controlling mosquitoes. Our aim was to identify fungal strains from the Amazon rain forest that produce metabolites with larvicidal activity against Aedes aegypti. Thirty-six fungal strains belonging to 23 different genera of fungi, isolated from water samples collected in the state of Amazonas, Brazil were cultivated. The liquid medium was separated from the mycelium by filtration. Medium fractions were extracted with ethyl acetate and isopropanol 9:1 volume:volume, and the mycelia with ethyl acetate and methanol 1:1. The extracts were vacuum dried and the larvicidal activity was evaluated in selective bioassays containing 500 μg/ml of the dried fungal extracts. Larval mortality was evaluated up to 72 h. None of the mycelium extracts showed larvicidal activity greater than 50% at 72 h. In contrast, 15 culture medium extracts had larvicidal activity equal to or greater than 50% and eight killed more than 90% of the larvae within 72 h. These eight extracts from fungi belonging to seven different genera (Aspergillus, Cladosporium, Trichoderma, Diaporthe, Albifimbria, Emmia, and Sarocladium) were selected for the determination of LC50 and LC90. Albifimbria lateralis (1160) medium extracts presented the lowest LC50 value (0.268 μg/ml) after 24 h exposure. Diaporthe ueckerae (1203) medium extracts presented the lowest value of LC90 (2.928 μg/ml) at 24 h, the lowest values of LC50 (0.108 μg/ml) and LC90 (0.894 μg/ml) at 48 h and also at 72 h (LC50 = 0.062 μg/ml and LC90 = 0.476 μg/ml). Extracts from Al. lateralis (1160) and D. ueckerae (1203) showed potential for developing new, naturally derived products, to be applied in integrated vector management programs against Ae. aegypti.

Keywords:  Aedes aegypti; arbovirus; biological control; larvicidal activity; metabolites

DOI:  https://doi.org/10.3389/fmicb.2021.743246
Zoonoses (Burlingt). 2021 ;1(1):

Zika Virus Overview: Transmission, Origin, Pathogenesis, Animal Model and Diagnosis.

Dallas Vue, Qiyi Tang.

  Zika virus (ZIKV) was first discovered in 1947 in Uganda. ZIKV did not entice much attention until Brazil hosted the 2016 Summer Olympics Game, where ZIKV attracted a global audience. ZIKV is a flavivirus that can be transmitted chiefly through the biting of the mosquito or sexually or by breastfeeding at a lower scale. As time passed, the recent discovery of how the ZIKV causes congenital neurodevelopmental defects, including microcephaly, makes us reevaluate the importance of ZIKV interaction with centrosome organization because centrosome plays an important role in cell division. When the ZIKV disrupts centrosome organization and mitotic abnormalities, this will alter neural progenitor differentiation. Altering the neural progenitor differentiation will lead to cell cycle arrest, increase apoptosis, and inhibit the neural progenitor cell differentiation, as this can lead to abnormalities in neural cell development resulting in microcephaly. Understanding the importance of ZIKV infection throughout the years, this review article gives an overview of the history, transmission routes, pathogenesis, animal models, and diagnosis.

Keywords:  Zika virus (ZIKV) centrosome; flavivirus; microcephaly

DOI:  https://doi.org/10.15212/zoonoses-2021-0017
Front Public Health. 2021 ;9 628799

Case Report: Neurologic Presentation of West Nile Virus: Difficult Diagnosis.

Eron G Manusov, Amalia Mora Campuzano, Omar Ahmed, Samantha Macias, Carolina Gomez de Ziegler, Gerardo Munoz Monaco.

  West Nile virus infections have surged across the globe. South Texas, located on the path of bird migration, with Culex quinquefasciatus and other Culex species, and biotic primers that predispose the area to epidemics (floods, amplifying hosts, and lack of mosquito control and prevention) remains a highly endemic area for arbovirus spread. West Nile virus infection ranges from mild febrile illness to severe central nervous system involvement. The purpose of this report is to highlight complex presentations of WNV and how confounding presenting symptoms delay diagnosis. The secondary goal is to describe how pandemics, such as SARS-CoV-2, can overwhelm the system and result in medical decision bias errors.

Keywords:  West Nile virus; altered mental status; neurologic abnormalities; opsoclonus; pandemic

DOI:  https://doi.org/10.3389/fpubh.2021.628799
Viruses. 2021 Nov 23. pii: 2352. [Epub ahead of print]13(12):

West Nile Virus Vaccination Protects against Usutu Virus Disease in Mice.

Rebecca Salgado, Seth A Hawks, Francesca Frere, Ana Vázquez, Claire Y-H Huang, Nisha K Duggal.

  West Nile virus (WNV) and Usutu virus (USUV) are mosquito-borne flaviviruses that can cause neuroinvasive disease in humans. WNV and USUV circulate in both Africa and Europe and are closely related. Due to antigenic similarity, WNV-specific antibodies and USUV-specific antibodies have the potential to bind heterologous viruses; however, it is unclear whether this interaction may offer protection against infection. To investigate how prior WNV exposure would influence USUV infection, we used an attenuated WNV vaccine that contains the surface proteins of WNV in the backbone of a dengue virus 2 vaccine strain and protects against WNV disease. We hypothesized that vaccination with this attenuated WNV vaccine would protect against USUV infection. Neutralizing responses against WNV and USUV were measured in vitro using sera following vaccination. Sera from vaccinated CD-1 and Ifnar1-/- mice cross-neutralized with WNV and USUV. All mice were then subsequently challenged with an African or European USUV strain. In CD-1 mice, there was no difference in USUV titers between vaccinated and mock-vaccinated mice. However, in the Ifnar1-/- model, vaccinated mice had significantly higher survival rates and significantly lower USUV viremia compared to mock-vaccinated mice. Our results indicate that exposure to an attenuated form of WNV protects against severe USUV disease in mice and elicits a neutralizing response to both WNV and USUV. Future studies will investigate the immune mechanisms responsible for the protection against USUV infection induced by WNV vaccination, providing critical insight that will be essential for USUV and WNV vaccine development.

Keywords:  Usutu virus; West Nile virus; flavivirus; neutralizing response; vaccine

DOI:  https://doi.org/10.3390/v13122352
JMIR Public Health Surveill. 2021 Dec 30. 7(12): e27266

Risk Factors Associated with a Dengue Fever Outbreak in Islamabad, Pakistan: Case-Control Study.

Amjad Mehmood, Fawad Khalid Khan, Ambreen Chaudhry, Zakir Hussain, Mumtaz Ali Laghari, Ijaz Shah, Zeeshan Iqbal Baig, Mirza Amir Baig, Yousef Khader, Aamer Ikram.

   BACKGROUND: On October 23, 2016, 79 dengue fever cases were reported from the Union Council Tarlai to Federal Disease Surveillance and Response Unit Islamabad. A team was established to investigate the suspected dengue outbreak.
OBJECTIVE: The aim of this study was to determine the extent of the outbreak and identify the possible risk factors.
METHODS: Active case finding was performed through a house-to-house survey. A case was defined as an acute onset of fever ≥38℃ in a resident of Tarlai from October 2 to November 11, 2016, with a positive dengue virus (nonstructural protein, NS-1) test and any of the two of following signs and symptoms: retroorbital/ocular pain, headache, rash, myalgia, arthralgia, and hemorrhagic manifestations. A structured questionnaire was used to collect data. Age- and sex-matched controls (1:1) were identified from residents in the same area as cases. Blood samples were taken and sent to the National Institute of Health for genotype identification.
RESULTS: During the active case search, 145 cases of dengue fever were identified by surveying 928 houses from October 23 to November 11, 2016. The attack rate (AR) was 17.0/10,000. The mean age was 34.4 (SD 14.4) years. More than half of the cases were male (80/145, 55.2%). Among all cases, 29% belonged to the 25-34 years age group and the highest AR was found in the 35-44 years age group (35.6/10,000), followed by the 55-64 years age group (35.5/10,000). All five blood samples tested positive for NS-1 (genotype DENV-2). The most frequent presenting signs/symptoms were fever and headache (both 100%). Stagnant water around houses (odds ratio [OR] 4.86, 95% CI 2.94-8.01; P<.001), presence of flower pots in the home (OR 2.73, 95% CI 1.67-4.45; P<.001), and open water containers (OR 2.24, 95% CI 1.36-3.60; P<.001) showed higher odds among cases. Conversely, use of bed nets (OR 0.44, 95% CI 0.25-0.77; P=.003), insecticidal spray (OR 0.33, 95% CI 0.22-0.55; P<.001), door screens (OR 0.27, 95% CI 0.15-0.46; P<.001), mosquito coil/mat (OR 0.26, 95% CI 0.16-0.44; P<.001), and cleanliness of the house (OR 0.12, 95% CI 0.05-0.26; P<.001) showed significant protective effects.
CONCLUSIONS: Stagnant water acting as breeding grounds for vectors was identified as the probable cause of spread of the dengue outbreak. Establishment of surveillance and an early reporting system along with use of protective measures against the vector are strongly recommended.

Keywords:  DENV-2; Islamabad; Pakistan; dengue fever; disease surveillance; epidemiology; outbreak; outbreak investigation; surveillance; vector

DOI:  https://doi.org/10.2196/27266
Biol Invasions. 2021 May;23(5): 1637-1648

Detrimental effects of a failed infection by a co-invasive parasite on a native congeneric parasite and its native host.

K M McIntire, S A Juliano.

  Biological invaders often are accompanied by co-invasive parasites that can alter ecosystem function and established native host-parasite relationships. When these co-invasive parasites establish in a community, they can affect native host fitness and native parasite infection intensity, prevalence, and success within the native host. The mosquito, Aedes triseriatus, is North American host to protozoan parasite, Ascogregarina barretti. In geographic regions invaded by the mosquito Aedes albopictus, A. triseriatus may also be infected by A. albopictus' co-invasive parasite, Ascogregarina taiwanensis. We tested the hypotheses that: 1) The presence of a co-invasive parasite will negatively affect native parasite fitness, yielding decreased infection intensity, prevalence, and infection success, which could be caused by immune induction of the host or inter-parasite competition, and 2) Coinfection with the native and co-invasive parasites will negatively affect host fitness, yielding increased larval development time and decreased survival and reproductive fitness, caused by increased costs of infection. In our coinfection experiments we find that any exposure to the co-invasive parasite resulted in decreased survivorship and increased development time of the host A. triseriatus, with or without coinfection by the native parasite. Exposure to both co-invasive and native parasites yielded reduced native parasite infection intensity in the host larva and reduced native parasite propagule production in the resulting male adults. Together, these results indicate not only the potential for the co-invasive parasite to alter the native host-parasite relationship, but to impact native host population dynamics.

Keywords:  Aedes; Ascogregarina; co-invasion; coinfection; host-parasite relationship

DOI:  https://doi.org/10.1007/s10530-021-02464-0
Vaccines (Basel). 2021 Dec 10. pii: 1464. [Epub ahead of print]9(12):

mRNA Vaccine Protects against Zika Virus.

Lex G Medina-Magües, Janina Gergen, Edith Jasny, Benjamin Petsch, Jaime Lopera-Madrid, Emily S Medina-Magües, Cristhian Salas-Quinchucua, Jorge E Osorio.

  Zika virus (ZIKV), a mosquito-borne flavivirus, has recently triggered global concern due to severe health complications. In 2015, a large ZIKV outbreak occurred in the Americas and established a link between ZIKV and microcephaly in newborn babies, spontaneous abortion, persistent viremia, and Guillain-Barré syndrome. While antivirals are being developed and prevention strategies focus on vector control, a safe and effective Zika vaccine remains unavailable. Messenger RNA (mRNA) vaccine technology has arisen as a flexible, simplified, and fast vaccine production platform. Here, we report on an mRNA vaccine candidate that encodes the pre-membrane and envelope (prM-E) glycoproteins of ZIKV strain Brazil SPH2015 and is encapsulated in lipid nanoparticles (LNPs). Our ZIKV prM-E mRNA-LNP vaccine candidate induced antibody responses that protected in AG129 mice deficient in interferon (IFN) alpha/beta/gamma (IFN-α/β/γ) receptors. Notably, a single administration of ZIKV prM-E mRNA-LNP protected against a lethal dose of ZIKV, while a two-dose strategy induced strong protective immunity. E-specific double-positive IFN-γ and TNF-α T-cells were induced in BALB/c mice after immunizations with a two-dose strategy. With the success of mRNA vaccine technology in facing the coronavirus (COVID-19) pandemic, our data support the development of prM-E RNActive® as a promising mRNA vaccine against Zika to counter future epidemics.

Keywords:  AG129; RNActive®; ZIKV; Zika vaccines; Zika virus; challenge; flavivirus; lipid nanoparticles; mRNA vaccines; mice

DOI:  https://doi.org/10.3390/vaccines9121464
Genome Res. 2021 Dec 29.

Transposable element variants and their potential adaptive impact in urban populations of the malaria vector Anopheles coluzzii.

Carlos Vargas-Chavez, Neil Michel Longo Pendy, Sandrine E Nsango, Laura Aguilera, Diego Ayala, Josefa González.

Anophelescoluzzii is one of the primary vectors of human malaria in sub-Saharan Africa. Recently, it has spread into the main cities of Central Africa threatening vector control programs. The adaptation of An. coluzzii to urban environments partly results from an increased tolerance to organic pollution and insecticides. Some of the molecular mechanisms for ecological adaptation are known, but the role of transposable elements (TEs) in the adaptive processes of this species has not been studied yet. As a first step toward assessing the role of TEs in rapid urban adaptation, we sequenced using long reads six An. coluzzii genomes from natural breeding sites in two major Central Africa cities. We de novo annotated TEs in these genomes and in an additional high-quality An. coluzzii genome, and we identified 64 new TE families. TEs were nonrandomly distributed throughout the genome with significant differences in the number of insertions of several superfamilies across the studied genomes. We identified seven putatively active families with insertions near genes with functions related to vectorial capacity, and several TEs that may provide promoter and transcription factor binding sites to insecticide resistance and immune-related genes. Overall, the analysis of multiple high-quality genomes allowed us to generate the most comprehensive TE annotation in this species to date and identify several TE insertions that could potentially impact both genome architecture and the regulation of functionally relevant genes. These results provide a basis for future studies of the impact of TEs on the biology of An. coluzzii.

DOI: https://doi.org/10.1101/gr.275761.121
Case Rep Infect Dis. 2021 ;2021 2131720

The Trend of Malaria Cases, Positivity Rate, and Determinant Factors in the Amhara Regional State, Ethiopia: A Mixed Method.

Chalachew Yenew, Sileshi Mulatu, Asaye Alamneh.

Objectives: The objectives of this study were to evaluate the trend of malaria cases and test positivity rate and explore determinant factors in the Amhara Regional State, Ethiopia.
Methods: A mixed study design (retrospective record data review and case study) was employed among 67 malaria officers from all zones in the region by using proportional allocation and the 1995 to 2020 malaria document review. 1995 to 2020 trend analysis was conducted using RStudio-1.2.5033. Vignette Focus Group Discussions (FGDs) were used to dig the possible factors for malaria case buildup using the purposive sampling technique, and a qualitative content analysis was used.
Results: The overall mean test positivity rate (TPR) was 21.9%, and about 80% of the land of the region was malarious, and 68% of the population was at risk of malaria in the study area from the data records of 1995 to 2020. The year 2012 to 2016 had the peak confirmed malaria cases, while the year 2016 to 2018 dramatically reduced followed by an increase in 2019/2020. The vignette FGDs identified that poor performance on Larval Source Management (LSM) and net utilization, no stock of some antimalarial medicine and supply, quality of malaria diagnosis services, the low commitment of leaders, and climatic anomalies facilitated surge of the disease in 2019/2020. No real accountability at all levels, low coverage of targeted vector control interventions, resource constraint, data quality and use for informed decision making, security issues and Internally Displaced Population (IDP) in various parts of the country, and the COVID-19 pandemic were the possible causes for case buildup.
Conclusions: This result revealed that the malaria incidence rate showed a remarkable decline. However, the average TPR was 21.9%. Hence, it provided the ongoing feedback, mass fever test and treatment, training to health professionals, and ongoing supportive supervision (SS) and mentorship, improved net utilization and indoor residual spraying (IRS) operation and close follow-up and conducted sensitization workshop, spot messages were transferred through mass media, and temporary case treatment and prevention centers at farm sites established may surpass the threshold of malaria.

DOI: https://doi.org/10.1155/2021/2131720
BMJ Glob Health. 2021 Dec;pii: e007453. [Epub ahead of print]6(12):

Eliminating malaria in conflict zones: public health strategies developed in the Sri Lanka Civil War.

Abrar Ahmed, Kara Grace Hounsell, Talha Sadiq, Mariam Naguib, Kirstyn Koswin, Chetha Dharmawansa, Thavachchelvi Rasan, Anita M McGahan.

  Despite the 26-year long civil war, Sri Lanka was declared malaria-free by WHO in 2016. This achievement was the result of nearly 30 years of elimination efforts following the last significant resurgence of malaria cases in Sri Lanka. The resurgence occurred in 1986-1987, when about 600 000 cases of malaria were detected. Obstacles to these efforts included a lack of healthcare workers in conflict zones, a disruption of vector control efforts, gaps in the medication supply chain, and rising malaria cases among the displaced population.This article seeks to describe the four strategies deployed in Sri Lanka to mitigate the aforementioned obstacles to ultimately achieve malaria elimination. The first approach was the support for disease elimination by the government of Sri Lanka and the Liberation Tamil Tigers of Elam. The second strategy was the balance of centralised leadership of the federal government and the decentralised programme operation at the regional level. The third strategy was the engagement of non-governmental stakeholders to fill in gaps left by the conflict to continue the elimination efforts. The last strategy is the ongoing efforts by the government, military and non-profit organisations to prevent the reintroduction of malaria.The lessons learnt from Sri Lanka have important implications for malaria-endemic nations that are in conflict such as Ethiopia, Afghanistan, Yemen and Somalia. To accomplish the World Health Assembly goal of reducing the global incidence and mortality of malaria by 90% by 2030, significant efforts are required to lessen the disease burden in conflict zones. In addition to the direct impacts of conflict on population health, conflicts may lead to increased risk of spread of malaria, both within a country and consequently, abroad.

Keywords:  malaria; public health

DOI:  https://doi.org/10.1136/bmjgh-2021-007453
Environ Health Perspect. 2021 Dec;129(12): 129001

Erratum: "The Complex Epidemiologic Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review".

Jenna E Coalson, Elizabeth J Anderson, Ellen M Santos, Valerie Madera Garcia, James K Romine, Joy K Luzingu, Brian Dominguez, Danielle M Richard, Ashley C Little, Mary H Hayden, Kacey C Ernst.

DOI: https://doi.org/10.1289/EHP10706