bims-mosdis Biomed News
on Mosquito distribution and disease
Issue of 2022‒10‒30
nineteen papers selected by
Richard Halfpenny
Staffordshire University
  1. Mosquito vector diversity and abundance in southern Botswana, in a global context of emerging pathogen transmission.
  2. Climate-driven mosquito-borne viral suitability index: measuring risk transmission of dengue, chikungunya and Zika in Mexico.
  3. Impact of temperature on infection with Japanese encephalitis virus of three potential urban vectors in Taiwan; Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus.
  4. Mosquito Vectors (Diptera: Culicidae) and Mosquito-Borne Diseases in North Africa.
  5. Escalating pyrethroid resistance in two major malaria vectors Anopheles funestus and Anopheles gambiae (s.l.) in Atatam, Southern Ghana.
  6. Surveillance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) as a Method for Prevention of Arbovirus Transmission in Urban and Seaport Areas of the Southern Coast of Brazil.
  7. Multidisciplinary approach for surveillance and risk identification of yellow fever and other arboviruses in Colombia.
  8. Screening of Circulation of Usutu and West Nile Viruses: A One Health Approach in Humans, Domestic Animals and Mosquitoes in Burkina Faso, West Africa.
  9. Dengue Incidence and Aedes Vector Collections in Relation to COVID-19 Population Mobility Restrictions.
  10. Factors enhancing the transmission of mosquito-borne arboviruses in Africa.
  11. Jamestown Canyon Virus in Collected Mosquitoes, Maine, United States, 2017-2019.
  12. Enhanced mosquito vectorial capacity underlies the Cape Verde Zika epidemic.
  13. Brazilian Populations of Aedes aegypti Resistant to Pyriproxyfen Exhibit Lower Susceptibility to Infection with Zika Virus.
  14. Life-history stage and the population genetics of the tiger mosquito Aedes albopictus at a fine spatial scale.
  15. Risk Assessment on the Release of Wolbachia-Infected Aedes aegypti in Yogyakarta, Indonesia.
  16. Host selection and forage ratio in West Nile virus-transmitting Culex mosquitoes: Challenges and knowledge gaps.
  17. Recurrent Episodes of Some Mosquito-Borne Viral Diseases in Nigeria: A Systematic Review and Meta-Analysis.
  18. Re-emergence of arbovirus diseases in the State of Rio de Janeiro, Brazil: The role of simultaneous viral circulation between 2014 and 2019.
  19. Rift Valley fever, Mauritania, 2020: Lessons from a one health approach.
  1. J Public Health Afr. 2022 Sep 07. 13(3): 2029
    Mosquito vector diversity and abundance in southern Botswana, in a global context of emerging pathogen transmission.
    Ntebaleng Makate, Pleasure Ramatlho, Tefo Kesaobaka Kgoroebutswe, Katherine Laycock, Giacomo Maria Paganotti.
      Background: The continued spread of infectious diseases by mosquitoes remains a formidable obstacle to the well-being of the people all over the world. Arboviruses are spread from one vertebrate host to another by vectors through intricate transmission cycles that involve the virus, the vertebrate host, and the vector. It is essential to acquire a better understanding of the current abundance and distribution of major vectors in order to adequately prepare for the possibility of arbovirus outbreaks. This is because the abundance and distribution of these major vectors determines the human populations that are at risk for the diseases that they transmit. The effects of climate change on the amount of mosquitoes and their ability to survive the seasons have had a substantial impact on the spread of diseases that are transmitted by vectors in many different parts of Botswana.Methods: The purpose was to collect mosquito samples in Gaborone and the neighboring areas in southern Botswana, including border stations. We collected different stages of the mosquito from each place, raised them to maturity, and then identified them. Both morphological and genetic studies were utilized in order to successfully identify the organism. The species of Culex mosquitoes accounted for 88.3% of the 5177 mosquitoes that were collected and identified, whereas the species of Aedes aegypti and Anopheles mosquitoes accounted for 11.5% and 0.2% respectively.
    Conclusions: These findings give entomological baseline data that will aid in the study of vectorial patterns and the estimation of future arboviral hazards provided by mosquitoes. Additionally, these findings document the diversity and abundance of mosquito species.
    Keywords:  Aedes aegypti; Culex spp; ovitrap; surveillance
    DOI:  https://doi.org/10.4081/jphia.2022.2029
  2. Int J Health Geogr. 2022 Oct 27. 21(1): 15
    Climate-driven mosquito-borne viral suitability index: measuring risk transmission of dengue, chikungunya and Zika in Mexico.
    Constantino Carreto, Roxana Gutiérrez-Romero, Tania Rodríguez.
      BACKGROUND: Climate variability influences the population dynamics of the Aedes aegypti mosquito that transmits the viruses that cause dengue, chikungunya and Zika. In recent years these diseases have grown considerably. Dengue is now the fastest-growing mosquito-transmitted disease worldwide, putting 40 per cent of the global population at risk. With no effective antiviral treatments or vaccines widely available, controlling mosquito population remains one of the most effective ways to prevent epidemics. This paper analyses the temporal and spatial dynamics of dengue in Mexico during 2000-2020 and that of chikungunya and Zika since they first appeared in the country in 2014 and 2015, respectively. This study aims to evaluate how seasonal climatological variability affects the potential risk of transmission of these mosquito-borne diseases. Mexico is among the world's most endemic countries in terms of dengue. Given its high incidence of other mosquito-borne diseases and its size and wide range of climates, it is a good case study.METHODS: We estimate the recently proposed mosquito-borne viral suitability index P, which measures the transmission potential of mosquito-borne pathogens. This index mathematically models how humidity, temperature and precipitation affect the number of new infections generated by a single infected adult female mosquito in a host population. We estimate this suitability index across all Mexico, at small-area level, on a daily basis during 2000-2020.
    RESULTS: We find that the index P predicted risk transmission is strongly correlated with the areas and seasons with a high incidence of dengue within the country. This correlation is also high enough for chikungunya and Zika in Mexico. We also show the index P is sensitive to seasonal climatological variability, including extreme weather shocks.
    CONCLUSIONS: The paper shows the dynamics of dengue, chikungunya and Zika in Mexico are strongly associated with seasonal climatological variability and the index P. This potential risk of transmission index, therefore, is a valuable tool for surveillance for mosquito-borne diseases, particularly in settings with varied climates and limited entomological capacity.
    Keywords:  Chikungunya; Climate change; Dengue; Health; Index P; Mexico; Mosquito-borne; Vector-born-diseases; Zika
    DOI:  https://doi.org/10.1186/s12942-022-00317-0
  3. Acta Trop. 2022 Oct 20. pii: S0001-706X(22)00418-1. [Epub ahead of print] 106726
    Impact of temperature on infection with Japanese encephalitis virus of three potential urban vectors in Taiwan; Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus.
    Wei-Ting Liu, Yi-Ju Chen, Cheng-Chen Chen, Kuei-Min Liao, Hau-You Tzeng, Wu-Chun Tu.
      Japanese encephalitis (JE) is an important mosquito-borne infectious disease in rural areas of Asia that is caused by Japanese encephalitis virus (JEV). Culex tritaeniorhynchus is the major vector of JEV, nevertheless there are other mosquitoes that may be able to transmit JEV. This study confirms that the midgut, head tissue, salivary glands, and reproductive tissue of Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus are all able to be infected with JEV after a virus-containing blood meal was ingested by female mosquitoes. Even though the susceptibility to JEV of the different tissues varies, the virus-positive rate increased with the number of days after JEV infection. Moreover, once JEV escapes the midgut barrier, the oral transmission rates of JEV were 16%, 2%, and 21% for Ae. albopictus, Ar. subalbatus, and Cx. quinquefasciatus at 14 days after infection at 30°C, respectively. There is no supporting evidence to suggest vertical transmission of JEV by the tested mosquitoes. Collectively, raising the temperature enhances JEV replication in the salivary gland of the three mosquito species, suggesting that global warming will enhance mosquito vector competence and that this is likely to lead to an increase in the probability of JEV transmission.
    Keywords:  Aedes albopictus; Armigeres subalbatus; Culex quinquefasciatus; JEV; Japanese encephalitis virus; oral transmission; vector competence
    DOI:  https://doi.org/10.1016/j.actatropica.2022.106726
  4. Insects. 2022 Oct 20. pii: 962. [Epub ahead of print]13(10):
    Mosquito Vectors (Diptera: Culicidae) and Mosquito-Borne Diseases in North Africa.
    Amira Nebbak, Lionel Almeras, Philippe Parola, Idir Bitam.
      Mosquitoes (Diptera: Culicidae) are of significant public health importance because of their ability to transmit major diseases to humans and animals, and are considered as the world's most deadly arthropods. In recent decades, climate change and globalization have promoted mosquito-borne diseases' (MBDs) geographic expansion to new areas, such as North African countries, where some of these MBDs were unusual or even unknown. In this review, we summarize the latest data on mosquito vector species distribution and MBDs affecting both human and animals in North Africa, in order to better understand the risks associated with the introduction of new invasive mosquito species such as Aedes albopictus. Currently, 26 mosquito species confirmed as pathogen vectors occur in North Africa, including Aedes (five species), Culex (eight species), Culiseta (one species) and Anopheles (12 species). These 26 species are involved in the circulation of seven MBDs in North Africa, including two parasitic infections (malaria and filariasis) and five viral infections (WNV, RVF, DENV, SINV and USUV). No bacterial diseases have been reported so far in this area. This review may guide research studies to fill the data gaps, as well as helping with developing effective vector surveillance and controlling strategies by concerned institutions in different involved countries, leading to cooperative and coordinate vector control measures.
    Keywords:  Algeria; Culicidae; Egypt; Libya; Morocco; North Africa; Tunisia; mosquito-borne diseases; mosquitoes; vectors
    DOI:  https://doi.org/10.3390/insects13100962
  5. BMC Infect Dis. 2022 Oct 25. 22(1): 799
    Escalating pyrethroid resistance in two major malaria vectors Anopheles funestus and Anopheles gambiae (s.l.) in Atatam, Southern Ghana.
    Leon M J Mugenzi, Gabriel Akosah-Brempong, Magellan Tchouakui, Benjamin D Menze, Theofelix A Tekoh, Micareme Tchoupo, Francis N Nkemngo, Murielle J Wondji, Ekene K Nwaefuna, Michael Osae, Charles S Wondji.
      BACKGROUND: Aggravation of insecticide resistance in malaria vectors is threatening the efforts to control malaria by reducing the efficacy of insecticide-based interventions hence needs to be closely monitored. This study investigated the intensity of insecticide resistance of two major malaria vectors An. funestus sensu stricto (s.s.) and An. gambiae sensu lato (s.l.) collected in southern Ghana and assessed the bio-efficacy of several long-lasting insecticidal nets (LLINs) against these mosquito populations.METHODS: The insecticide susceptibility profiles of Anopheles funestus s.s. and Anopheles gambiae s.l. populations from Obuasi region (Atatam), southern Ghana were characterized and the bio-efficacy of some LLINs was assessed to determine the impact of insecticide resistance on the effectiveness of these tools. Furthermore, molecular markers associated with insecticide resistance in both species were characterized in the F0 and F1 populations using PCR and qPCR methods.
    RESULTS: Anopheles funestus s.s. was the predominant species and was resistant to pyrethroids, organochlorine and carbamate insecticides, but fully susceptible to organophosphates. An. gambiae s.l. was resistant to all four insecticide classes. High intensity of resistance to 5 × and 10 × the discriminating concentration (DC) of pyrethroids was observed in both species inducing a considerable loss of efficacy of long-lasting insecticidal nets (LLINs). Temporal expression analysis revealed a massive 12-fold increase in expression of the CYP6P4a cytochrome P450 gene in An. funestus s.s., initially from a fold change of 41 (2014) to 500 (2021). For both species, the expression of candidate genes did not vary according to discriminating doses. An. gambiae s.l. exhibited high frequencies of target-site resistance including Vgsc-1014F (90%) and Ace-1 (50%) while these mutations were absent in An. funestus s.s.
    CONCLUSIONS: The multiple and high intensity of resistance observed in both malaria vectors highlights the need to implement resistance management strategies and the introduction of new insecticide chemistries.
    Keywords:  Anopheles; Atatam; Insecticide resistance; Long-lasting insecticidal nets; Malaria
    DOI:  https://doi.org/10.1186/s12879-022-07795-4
  6. J Med Entomol. 2022 Oct 28. pii: tjac143. [Epub ahead of print]
    Surveillance of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) as a Method for Prevention of Arbovirus Transmission in Urban and Seaport Areas of the Southern Coast of Brazil.
    Mario Arturo Acero-Sandoval, Angela Maria Palacio-Cortés, Mario Antônio Navarro-Silva.
      Entomological surveillance is a traditional method to measure presence, distribution, and seasonal variation of vectors in urban areas, and is essential to targeted control activities to prevent arbovirus transmission. Ovitraps as one of the main components of surveillance programs, enable determination of female oviposition behavior, as well as identification of seasonal variations of the vector. The goals of this study were 1) to detect the mosquitos (Aedes aegypti Linnaeus) and (Aedes albopictus Skuse) (Diptera:Culicidae), in Paranaguá city, 2) to assess ovitrap positive index (OPI), egg density index (EDI), and their relationship with meteorological variables, and 3) to evaluate the vertical transmission of dengue, Zika, and chikungunya in Ae. aegypti and Ae. albopictus. The study was carried out in urban areas of Paranaguá city, an important port region of Brazil, from June 2017 to November 2018. The city was divided into 16 area-clusters. Three-hundred and thirty-one ovitraps were installed monthly, remaining for four days in selected places. Kernel density maps were done to compare the spatiotemporal distribution of collected eggs. Areas which maintained constant oviposition associated with vector activity were identified and were found to overlap the area-clusters with the highest EDI. As viral RNA was not detected, vertical transmission was likely not a maintenance mechanism of arbovirus circulation in Ae. aegypti and Ae. albopictus vectors. This study reiterates the importance, efficiency, and feasibility of ovitraps to monitor the presence and dynamics of Aedes spp. populations.
    Keywords:   Stegomyia ; ovitrap; vertical virus transmission
    DOI:  https://doi.org/10.1093/jme/tjac143
  7. One Health. 2022 Dec;15 100438
    Multidisciplinary approach for surveillance and risk identification of yellow fever and other arboviruses in Colombia.
    Juan S Mantilla-Granados, Diana Sarmiento-Senior, Jaime Manzano, María-Angélica Calderón-Peláez, Myriam Lucía Velandia-Romero, Luz Stella Buitrago, Jaime E Castellanos, Víctor Alberto Olano.
      Arbovirus, a critical threat to human health, have complex and dynamic life cycles. With reports of Yellow fever virus (YFV) causing spillover from sylvatic transmission cycles, and dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV) viruses expanding from urban to rural areas. We explored a multidisciplinary approach to analyze arbovirus transmission through vectors, and identify biological and sociodemographic determinants associated with their transmission risk in urban and rural areas in a Colombian municipality. We visited 178 urban and 97 rural households, registered sociodemographic characteristics and vaccination status for each of these households, collected adult and immature mosquitoes at the intra-, peri-, and extra-domicile, and surveyed forest patches in rural areas. Infections of YFV, DENV, ZIKV, and CHIKV in the mosquitoes collected in the wild were analyzed using a reverse transcriptase PCR. We identified various risk factors of transmission associated with a high Aedes aegypti infestation in urban areas and their presence in rural settlements and Haemagogus janthinomys and other sylvatic mosquitoes near urban areas. The collected Ae. aegypti females from urban areas had a high infection rate of YFV (5.8%) and CHIKV (58.8%), and those from rural settlements had a high infection rate of DENV (33%), CHIKV (16.7%), and ZIKV (16.7%). The infection rates of YFV in the thorax of the sylvatic mosquitoes H. janthinomys and Aedes serratus collected from the forest patches were 14.3 and 42.1%, respectively. We could discern the transmission determinants associated with climatic, socioeconomic, and anthropogenic factors and YFV vaccination status. This multidisciplinary approach for surveillance of arboviral diseases allowed us to independently detect and integrate factors indicating an early risk of rural transmission of DENV, CHIKV, and ZIKV and rural and urban outbreaks of YFV in the study area. This study provides a helpful tool for designing and focalizing prevention strategies.
    Keywords:  Aedes; Arbovirus; Haemagogus; Mosquitoes; Outbreak; Public health
    DOI:  https://doi.org/10.1016/j.onehlt.2022.100438
  8. Microorganisms. 2022 Oct 12. pii: 2016. [Epub ahead of print]10(10):
    Screening of Circulation of Usutu and West Nile Viruses: A One Health Approach in Humans, Domestic Animals and Mosquitoes in Burkina Faso, West Africa.
    Bachirou Tinto, Didier Patinde Alexandre Kaboré, Thérèse Samdapawindé Kagoné, Orianne Constant, Jonathan Barthelemy, Alice Kiba-Koumaré, Philippe Van de Perre, Roch Kounbobr Dabiré, Thierry Baldet, Serafin Gutierrez, Patricia Gil, Dramane Kania, Yannick Simonin.
      Usutu virus (USUV) and West Nile virus (WNV) are phylogenetically closely related arboviruses. These viruses mainly follow an enzootic cycle involving mosquitoes and birds, but they occasionally infect humans and other mammals, inducing neurotropic disorders. Since the discovery of USUV, only two human cases have been reported in Africa, including one in Burkina Faso in 2004. Since then, no studies have been conducted to measure the extent of the circulation of this virus in Burkina Faso, and no study regarding the circulation of WNV has been conducted. Our study aimed to determine the seroprevalence of USUV and WNV in blood donations and in animals (horses, dogs, chickens and pigeons) and to perform molecular screening in patients with febrile fever and in Culex quinquefasciatus and Aedes aegypti mosquitoes. The prevalence of USUV and WNV was studied by serological (ELISA and microneutralization tests) and molecular analyses (RT-qPCR) of mosquito, dog, domestic bird, horse, and human samples in Burkina Faso between 2019 and 2021. We detected a very active transmission of both viruses in Burkina Faso. WNV and USUV seroprevalence is particularly high in humans (19.16% and 14.17%, respectively) and horses (17.28% and 6.17%). Molecular screening did not detect WNV or USUV in the mosquito or human samples tested. Our study shows an active spread of USUV and WNV in Burkina Faso, especially for WNV. This study highlights the value of developing surveillance programs to better prevent, detect, and alert people to USUV and WNV circulation in both primary and incidental hosts.
    Keywords:  Burkina Faso; Usutu virus; West Nile virus; domestic animals; humans; mosquitoes
    DOI:  https://doi.org/10.3390/microorganisms10102016
  9. Trop Med Infect Dis. 2022 Oct 07. pii: 287. [Epub ahead of print]7(10):
    Dengue Incidence and Aedes Vector Collections in Relation to COVID-19 Population Mobility Restrictions.
    Sinnathamby Noble Surendran, Ratnarajah Nagulan, Annathurai Tharsan, Kokila Sivabalakrishnan, Ranjan Ramasamy.
      Contrary to expectation, dengue incidence decreased in many countries during the period when stringent population movement restrictions were imposed to combat COVID-19. Using a seasonal autoregressive integrated moving average model, we previously reported a 74% reduction in the predicted number of dengue cases from March 2020 to April 2021 in the whole of Sri Lanka, with reductions occurring in all 25 districts in the country. The reduction in dengue incidence was accompanied by an 87% reduction in larval collections of Aedes vectors in the northern city of Jaffna. It was proposed that movement restrictions led to reduced human contact and blood feeding by Aedes vectors, accompanied by decreased oviposition and vector densities, which were responsible for diminished dengue transmission. These findings are extended in the present study by investigating the relationship between dengue incidence, population movement restrictions, and vector larval collections between May 2021 and July 2022, when movement restrictions began to be lifted, with their complete removal in November 2021. The new findings further support our previous proposal that population movement restrictions imposed during the COVID-19 pandemic reduced dengue transmission primarily by influencing human-Aedes vector interaction dynamics.
    Keywords:  Aedes aegypti; Aedes albopictus; COVID-19; Jaffna; Sri Lanka; dengue incidence; dengue transmission; dengue vectors; mosquito vector–human interactions; population movement restrictions
    DOI:  https://doi.org/10.3390/tropicalmed7100287
  10. Virusdisease. 2022 Oct 18. 1-12
    Factors enhancing the transmission of mosquito-borne arboviruses in Africa.
    Sandra Ateutchia Ngouanet, Samuel Wanji, Anges Yadouleton, Maurice Demanou, Rousseau Djouaka, Ferdinand Nanfack-Minkeu.
      Arthropod-borne viruses (Arboviruses) replicate in vertebrates and invertebrates and are mainly transmitted by mosquitoes. Between 2000 and 2021, several arbovirus outbreaks were recorded in African countries, including dengue, yellow fever, Chikungunya, Zika, and O'nyong nyong. Most often, the causes and factors involved in these outbreaks are unknown. We aimed to understand current knowledge regarding factors responsible for the persistent transmission and emergence of mosquito-borne arboviruses in Africa and to identify critical research gaps important for preventing future outbreaks. We used a systematic literature review between 2020 and 2021, to show that the main identified factors favoring the arbovirus outbreak in Africa are low vaccination coverage, high density and diversity of competent mosquitoes, insecticide resistance of mosquito vectors, and a scarcity of data on arboviruses. Further studies on arboviruses may include studies of competence to viral strains and the susceptibility of mosquito vectors to insecticides. Because of the detrimental effects of insecticides on human health and the environment, viral paratransgenesis and other biological control methods should be explored as alternatives or as supplements to insecticides.Graphical abstract: Illustration of factors identified for promoting the transmission of arbovirus in Africa. The main factors are the lack of drugs and vaccines, low coverage of vaccination when a vaccine exists, competence of mosquitoes to viruses, diversity and high density of vectors. Climate change, urbanization, deforestation and agricultural practices, lead to a richness and high density of vectors.
    Keywords:  Africa; Arboviruses; Disease outbreaks; Mosquitoes; Public health; Transmission factors
    DOI:  https://doi.org/10.1007/s13337-022-00795-7
  11. Emerg Infect Dis. 2022 Nov;28(11): 2330-2333
    Jamestown Canyon Virus in Collected Mosquitoes, Maine, United States, 2017-2019.
    Elizabeth F Schneider, Rebecca M Robich, Susan P Elias, Charles B Lubelczyk, Danielle S Cosenza, Robert P Smith.
      Jamestown Canyon virus (JCV) is a mosquito-borne arbovirus that circulates in North America. We detected JCV in 4 pools of mosquitoes collected from midcoastal Maine, USA, during 2017-2019. Phylogenetic analysis of a JCV sequence obtained from Aedes cantator mosquitoes clustered within clade A, which also circulates in Connecticut, USA.
    Keywords:  Jamestown Canyon virus; Maine; United States; mosquitoes; orthobunyavirus; phylogenetics; vector-borne infections; viruses; zoonoses
    DOI:  https://doi.org/10.3201/eid2811.212382
  12. PLoS Biol. 2022 Oct;20(10): e3001864
    Enhanced mosquito vectorial capacity underlies the Cape Verde Zika epidemic.
    Noah H Rose, Stéphanie Dabo, Silvânia da Veiga Leal, Massamba Sylla, Cheikh T Diagne, Oumar Faye, Ousmane Faye, Amadou A Sall, Carolyn S McBride, Louis Lambrechts.
      The explosive emergence of Zika virus (ZIKV) across the Pacific and Americas since 2007 was associated with hundreds of thousands of human cases and severe outcomes, including congenital microcephaly caused by ZIKV infection during pregnancy. Although ZIKV was first isolated in Uganda, Africa has so far been exempt from large-scale ZIKV epidemics, despite widespread susceptibility among African human populations. A possible explanation for this pattern is natural variation among populations of the primary vector of ZIKV, the mosquito Aedes aegypti. Globally invasive populations of Ae. aegypti outside of Africa are considered effective ZIKV vectors because they are human specialists with high intrinsic ZIKV susceptibility, whereas African populations of Ae. aegypti across the species' native range are predominantly generalists with low intrinsic ZIKV susceptibility, making them less likely to spread viruses in the human population. We test this idea by studying a notable exception to the patterns observed across most of Africa: Cape Verde experienced a large ZIKV outbreak in 2015 to 2016. We find that local Ae. aegypti in Cape Verde have substantial human-specialist ancestry, show a robust behavioral preference for human hosts, and exhibit increased susceptibility to ZIKV infection, consistent with a key role for variation among mosquito populations in ZIKV epidemiology. These findings suggest that similar human-specialist populations of Ae. aegypti in the nearby Sahel region of West Africa, which may be expanding in response to rapid urbanization, could serve as effective vectors for ZIKV in the future.
    DOI:  https://doi.org/10.1371/journal.pbio.3001864
  13. Viruses. 2022 Oct 06. pii: 2198. [Epub ahead of print]14(10):
    Brazilian Populations of Aedes aegypti Resistant to Pyriproxyfen Exhibit Lower Susceptibility to Infection with Zika Virus.
    Kauara Brito Campos, Abdullah A Alomar, Bradley H Eastmond, Marcos Takashi Obara, Barry W Alto.
      Zika virus (ZIKV) infection has caused devastating consequences in Brazil as infections were associated with neurological complications in neonates. Aedes aegypti is the primary vector of ZIKV, and the evolution of insecticide resistance (IR) in this species can compromise control efforts. Although relative levels of phenotypic IR in mosquitoes can change considerably over time, its influence on vector competence for arboviruses is unclear. Pyriproxyfen (PPF)-resistant populations of Ae. aegypti were collected from five municipalities located in Northeast of Brazil, which demonstrated different resistance levels; low (Serrinha, Brumado), moderate (Juazeiro do Norte, Itabuna), and high (Quixadá). Experimental per os infection using ZIKV were performed with individuals from these populations and with an insecticide susceptible strain (Rockefeller) to determine their relative vector competence for ZIKV. Although all populations were competent to transmit ZIKV, mosquitoes derived from populations with moderate to high levels of IR exhibited similar or lower susceptibility to ZIKV infection than those from populations with low IR or the susceptible strain. These observations suggest an association between IR and arbovirus infection, which may be attributable to genetic hitchhiking. The use of PPF to control Brazilian Ae. aegypti may be associated with an indirect benefit of reduced susceptibility to infection, but no changes in disseminated infection and transmission of ZIKV among PPF-resistant phenotypes.
    Keywords:  Aedes aegypti; Zika virus; insecticide resistance; per os infection; pyriproxyfen; vector competence; viral titer
    DOI:  https://doi.org/10.3390/v14102198
  14. Med Vet Entomol. 2022 Oct 27.
    Life-history stage and the population genetics of the tiger mosquito Aedes albopictus at a fine spatial scale.
    Emily M X Reed, Michael H Reiskind, Martha O Burford Reiskind.
      As a widespread vector of disease with an expanding range, the mosquito Aedes albopictus Skuse (Diptera: Culicidae) is a high priority for research and management. A. albopictus has a complex life history with aquatic egg, larval and pupal stages, and a terrestrial adult stage. This requires targeted management strategies for each life stage, coordinated across time and space. Population genetics can aid in A. albopictus control by evaluating patterns of genetic diversity and dispersal. However, how life stage impacts population genetic characteristics is unknown. We examined whether patterns of A. albopictus genetic diversity and differentiation changed with life stage at a spatial scale relevant to management efforts. We first conducted a literature review of field-caught A. albopictus population genetic papers and identified 101 peer-reviewed publications, none of which compared results between life stages. Our study uniquely examines population genomic patterns of egg and adult A. albopictus at five sites in Wake County, North Carolina, USA, using 8425 single nucleotide polymorphisms. We found that the level of genetic diversity and connectivity between sites varied between adults and eggs. This warrants further study and is critical for research aimed at informing local management.
    Keywords:  Aedes albopictus; invasive species; life stage; mosquito; population genetics
    DOI:  https://doi.org/10.1111/mve.12618
  15. Insects. 2022 Oct 12. pii: 924. [Epub ahead of print]13(10):
    Risk Assessment on the Release of Wolbachia-Infected Aedes aegypti in Yogyakarta, Indonesia.
    Damayanti Buchori, Amanda Mawan, Indah Nurhayati, Aryati Aryati, Hari Kusnanto, Upik Kesumawati Hadi.
      Wolbachia-infected Aedes aegypti is the latest technology that was developed to eliminate dengue fever. The Ministry of Research and Technology of the Republic of Indonesia (Kemenristekdikti) established an expert group to identify future potential risks that may occur over a period of 30 years associated with the release of Wolbachia-infected Ae. aegypti. The risk assessment consisted of identifying different hazards that may have impacts on humans and the environment. From the consensus among the experts, there were 56 hazards identified and categorized into 4 components, namely, ecological matters, efficacy in mosquito management, economic and sociocultural issues, and public health standards. There were 19 hazards in the ecological group. The overall likelihood in the ecology of the mosquito is very low (0.05), with moderate consequence (0.74), which resulted in negligible risk. For the efficacy in mosquito management group, there were 12 hazards that resulted in very low likelihood (0.11) with high consequence (0.85). The overall risk for mosquito management efficacy was very low (0.09). There were 14 hazards identified in the public health standard with very low likelihood (0.07), moderate consequence (0.50) and negligible risk (0.04). Lastly, 13 hazards were identified in the economic and sociocultural group with low likelihood (0.01) but of moderate consequence (0.5), which resulted in a very low risk (0.09). The risk severity level of the four components leading to the endpoint risk of "cause more harm" due to releasing Wolbachia-infected Ae. aegypti is negligible (0.01).
    Keywords:  Wolbachia; Yogyakarta; dengue fever; eliminate dengue program; risk analysis
    DOI:  https://doi.org/10.3390/insects13100924
  16. PLoS Negl Trop Dis. 2022 Oct;16(10): e0010819
    Host selection and forage ratio in West Nile virus-transmitting Culex mosquitoes: Challenges and knowledge gaps.
    Nicola Riccetti, Augusto Fasano, Federico Ferraccioli, Jaime Gomez-Ramirez, Nikolaos I Stilianakis.
      BACKGROUND: To date, no specific therapy or vaccination is available for West Nile virus (WNV) infections in humans; preventive strategies represent the only possibility to control transmission. To focus these strategies, detailed knowledge of the virus dynamics is of paramount importance. However, several aspects of WNV transmission are still unclear, especially regarding the role of potential vertebrate host species. Whereas mosquitoes' intrinsic characteristics cause them to favour certain hosts (host preference), absolute selection is impossible in natural settings. Conversely, the selection carried out among available hosts and influenced from hosts' availability and other ecological/environmental factors is defined as host selection.METHODOLOGY/PRINCIPAL FINDINGS: In July 2022, we searched PubMed database for original articles exploring host selection among WNV-transmitting Culex mosquitoes, the main WNV vector. We considered only original field studies estimating and reporting forage ratio. This index results from the ratio between the proportion of blood meals taken by mosquitoes on potential host species and the hosts' relative abundance. From the originally retrieved 585 articles, 9 matched the inclusion criteria and were included in this review. All but one of the included studies were conducted in the Americas, six in the United States, and one each in Mexico and Colombia. The remaining study was conducted in Italy. American Robin, Northern Cardinal, and House Finch were the most significantly preferred birds in the Americas, Common Blackbird in Italy.
    CONCLUSIONS/SIGNIFICANCE: Although ornithophilic, all observed WNV-transmitting mosquitoes presented opportunistic feeding behaviour. All the observed species showed potential to act as bridges for zoonotic diseases, feeding also on humans. All the observed mosquitoes presented host selection patterns and did not feed on hosts as expected by chance alone. The articles observe different species of mosquitoes in different environments. In addition, the way the relative host abundance was determined differed. Finally, this review is not systematic. Therefore, the translation of our results to different settings should be conducted cautiously.
    DOI:  https://doi.org/10.1371/journal.pntd.0010819
  17. Pathogens. 2022 Oct 08. pii: 1162. [Epub ahead of print]11(10):
    Recurrent Episodes of Some Mosquito-Borne Viral Diseases in Nigeria: A Systematic Review and Meta-Analysis.
    Anyebe Bernard Onoja, Arome Cornelius Omatola, Mamoudou Maiga, Ishaya Samuel Gadzama.
      Different ecological zones favor the breeding of Aedes species. The molecular epidemiology of dengue virus (DENV), yellow fever virus (YFV), and Chikungunya virus (CHIKV) was determined from outbreaks and surveillance activities in Nigeria. Twenty-eight DENV, twenty-five YFV, and two CHIKV sequences from Nigeria were retrieved from GenBank. Genotyping was performed with a genome detective typing tool. The evolutionary comparison was performed by the Maximum Likelihood method on MEGA. Chi-square was used to compare the association between the proportions of viral infections at different times. Six DENV-1 were detected in 1964, 1965, 1978, 2007, and 2018. Nineteen DENV-2 strains were reported, four belonging to sylvatic VI, one belonging to cosmopolitan II, and twelve to Asian I genotype V. DENV-2 genotype VI was detected in 1966, and genotypes II and V in 2019. All three DENV-3 were detected in 2018, while only one DENV-4 was identified in 2019. YFV was reported in 1946 and then in the 60s, 70s, 80s, 90s, 2018, and 2019 with reports to date. CHIKV is still circulating following its identification in 1964 and 1965. Recurrent episodes of dengue, Chikungunya, and yellow fever continue unabated. Vector control initiatives and immunization should be greatly sustained.
    Keywords:  Aedes species; Chikungunya; Nigeria; arbovirus; dengue; yellow fever virus
    DOI:  https://doi.org/10.3390/pathogens11101162
  18. One Health. 2022 Dec;15 100427
    Re-emergence of arbovirus diseases in the State of Rio de Janeiro, Brazil: The role of simultaneous viral circulation between 2014 and 2019.
    Olivia M Man, Trevon L Fuller, Joelle I Rosser, Karin Nielsen-Saines.
      The burden of arbovirus diseases in Brazil has increased within the past decade due to the emergence of chikungunya and Zika and endemic circulation of all four dengue serotypes. Changes in temperature and rainfall patterns may alter conditions to favor vector-host transmission and allow for cyclic re-emergence of disease. We sought to determine the impact of climate conditions on arbovirus co-circulation in Rio de Janeiro, Brazil. We assessed the spatial and temporal distributions of chikungunya, dengue, and Zika cases from Brazil's national notifiable disease information system (SINAN) and created autoregressive integrated moving average models (ARIMA) to predict arbovirus incidence accounting for the lagged effect of temperature and rainfall. Each year, we estimate that the combined arboviruses were associated with an average of 8429 to 10,047 lost Disability-Adjusted Life Years (DALYs). After controlling for temperature and precipitation, our model predicted a three cycle pattern where large arbovirus outbreaks appear to be primed by a smaller scale surge and followed by a lull of cases. These dynamic arbovirus patterns in Rio de Janeiro support a mechanism of susceptibility enhancement until the theoretical threshold of population immunity allows for temporary cross protection among certain arboviruses. This suspected synergy presents a major public health challenge due to overlapping locations and seasonality of arbovirus diseases, which may perpetuate disease burden and overwhelm the health system.
    Keywords:  Arboviruses; Brazil; Chikungunya; Dengue; Environment; Zika
    DOI:  https://doi.org/10.1016/j.onehlt.2022.100427
  19. One Health. 2022 Dec;15 100413
    Rift Valley fever, Mauritania, 2020: Lessons from a one health approach.
    Yahya Barry, Ahmed Elbara, Mohamed Abdallahi Bollahi, Ahmed B Ould El Mamy, Mokhtar Fall, Abdellahi Diambar Beyit, Mariem Seyidna Khayar, Ba Aliou Demba, Mohamed Limine Haki, Ousmane Faye, Ludovic Plee, Etienne Bonbon, Baba Doumbia, Elena Arsevska, Catherine Cêtre-Sossah.
      A new outbreak of Rift Valley fever (RVF) occurred in Mauritania from September to November 2020, involving 78 reported human cases and 186 reported animal cases. Eleven out of the 13 regions of the country were affected by the epidemic, with the highest number of both human and animal cases in Tagant, Assaba and Brakna regions. The most affected animal species in this outbreak was camels, followed by small ruminants. Among the 10 mosquito species caught, 7 species, Culex poicilipes, Cx. quinquefasciatus, Cx. antennatus, Cx. univitattus, Aedes vexans, Mansonia africana and Ma. uniformis, are known to be involved in the transmission of RVF virus. Phylogenetic analyses based on the partial NSs gene revealed close proximity between the human/animal Mauritania 2020 viral strains and the Mauritania 2015/Niger 2016 strains, suggesting re-emergence of the RVF virus in the country since the last reported outbreak in 2015.
    DOI:  https://doi.org/10.1016/j.onehlt.2022.100413
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