Mosquitoes and Mosquito-borne diseases

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Mosquitoes (Diptera: Culicidae) and mosquito borne diseases in Mali, West Africa

Mosquitoes (Diptera: Culicidae) and mosquito borne diseases in Mali, West Africa

Mosquito-borne diseases cause major human diseases in almost every part of the world. In West Africa, and notably in Mali, vector control measures help reduce the impact of mosquito-borne diseases, although malaria remains a threat to both morbidity and mortality. The most recent overview article on mosquitoes in Mali was published in 1961, with a total of 88 species. Our present review focuses on mosquitoes of medical importance among which the Anopheles vectors of Plasmodium and filaria, as well as the Culex and Aedes vectors of arboviruses. It aims to provide a concise update of the literature on Culicidae, covering the ecological areas in which the species are found but also the transmitted pathogens and recent innovative tools for vector surveys. This review highlights the recent introduction of invasive mosquito species, including Aedes albopictus and Culex neavei. The comprehensive list of mosquito species currently recorded includes 106 species (28 species of the Anophelinae and 78 species of the Culicinae). There are probable gaps in our knowledge concerning mosquitoes of the subfamily Culicinae and northern half of Mali because most studies have been carried out on the genus Anopheles and have taken place in the southern part of the country. It is hoped that this review may be useful to decision makers responsible for vector control strategies and to
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A Transdisciplinary Approach to Managing Emerging and Resurging Mosquito-Borne Diseases in the Western Pacific Region

A Transdisciplinary Approach to Managing Emerging and Resurging Mosquito-Borne Diseases in the Western Pacific Region

As climate change may increase global temperatures, the potential spatial range of arthropod species able to vector diseases may also increase [15–17]. Combined with subsequent increases in travel and urbanization, this means more individuals are likely to come into contact with mosquito-borne diseases specifically [3]. Biosecurity is defined by the National Academy of Sciences as “security against the inadvertent, inappropriate, or intentional malicious or malevolent use of potentially dangerous biological agents or biotechnology, including the development, production, stockpiling, or use of biological weapons as well as natural outbreaks of newly emergent and epidemic diseases” [18] and is key to preventing the spread of pathogens across country borders. Ectoparasites such as mosquitoes are of biosecurity concern if they have three characteristics: (1) arrival: the ectoparasite is able to survive the quarantine measures (if any) in place before, during, and after transit; (2) establishment: the ectoparasite is able to find a suitable habitat to colonize in the new location; and, (3) spread: the ectoparasite can adapt to life cycle differences in the new location, like the availability of suitable hosts and/or breeding sites. The flow of mosquito-borne pathogens across international borders due to poor biosecurity further widens their threat to human health.
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Surveillance and Control of Selected Mosquito-borne Diseases in Florida Guidebook

Surveillance and Control of Selected Mosquito-borne Diseases in Florida Guidebook

Other arboviral encephalitides of minor public health significance that occur in Florida are caused by Everglades virus (EVEV), an alphavirus, (family Togaviridae) and La Crosse, Keystone and Jamestown Canyon viruses (family Bunyaviridae; California group). To date, no reported human cases of WEE have been acquired in Florida. While serologic evidence of EVEV infection has been documented in south Florida, only three clinical cases have ever been identified, two near Homestead and Florida City in Miami-Dade County (1968 and 1971) and one near Vero Beach (1968). Highlands J virus (HJV) is a mosquito-transmitted alphavirus that is similar to EEEV in its natural cycle. HJV is transmitted from Cs. melanura mosquitoes to songbirds in freshwater swamps. It has a low pathogenicity in mammals and rarely causes disease in humans or horses. During the 1990-91 SLE outbreak in Florida, four patients were reported to be infected with SLEV and HJV; however, exposure to HJV has not been associated with human illness. There have been outbreaks reported in caged birds but the symptoms are mild.
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Surveillance and Control of Selected Mosquito-borne Diseases in Florida Guidebook

Surveillance and Control of Selected Mosquito-borne Diseases in Florida Guidebook

The peak period of transmission in Florida is July through September. Like SLEV, the natural cycle of WNV appears to involve Culex mosquitoes and wild birds. However, unlike SLEV, WNV causes high rates of mortality in certain families of birds, especially corvids (crows and jays) and ratites (e.g., emu and ostrich). It is also pathogenic for horses and some camelids. In Florida, WNV has been identified most frequently in Cx. nigripalpus mosquitoes. Culex quinquefasciatus has also been found to be an important vector in the southern US, particularly in urban areas. Three hundred and eighteen human WNV illness cases were reported in Florida between 2001- 2013 with the highest number of cases reported in 2003 (93 cases). In 2012, a nationwide outbreak of WNV infections occurred with high intensity transmission occurring in eastern Texas and the Midwest. The 2012 outbreak also involved north Florida, with all but one of 68 Florida acquired cases reporting exposure in the northern part of the state. West Nile virus was isolated from 2 pools of Cx. nigripalpus mosquitoes collected in Duval County where 28 of the human cases were reported in 2012. More than 1,000 cases of equine WNV infection were confirmed in Florida in the past 10 years. A WNV illness outbreak also occurred in alligators at an alligator farm in Glades County in 2011; infected alligators amplify virus and may transmit virus to other alligators and people through fecal shedding and contact with tissues while viremic 5 .
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Knowledge Attitude and Practices Related on Prevention of Mosquito Borne Diseases and Sanitation Conditions in a Salvadoran Urban Community

Knowledge Attitude and Practices Related on Prevention of Mosquito Borne Diseases and Sanitation Conditions in a Salvadoran Urban Community

In the present community, according to the KAP results and the hierarchy analysis of the importance, an intervention to prevent Aedes infestation should be focused on pre- ventive practices against both immature and adult mosquitoes and to strengthen the importance of household practices to prevent MBDs. Governmental institutions should to promote covering water containers and use of windows and door screens as carried out by Garcia-Betancourt et al. [38]. Health officials should explain this practice to the community through workshops; features of the water containers should be evaluated and local manufactures should be involved to produce water container covers. This in- tervention can be complemented by promoting other alternatives like the application of little dab known in Spanish as la untadita and to evaluate the introduction of local lar- vivorous fishes as an alternative to larvicide application. However some studies identi- fied larvavorous fishes as a useful method to eliminate mosquitoes larvae cheaper than larvicide [39] [40], there is no evidence to demonstrate any community effectiveness of this method as a single agent [41]. Moreover, viability of this implementation has to be evaluated considering the presence of chlorine in water because some species do not tolerate chlorine levels of treated drinking water [42]. Finally, the workshop should consider rational use of household pesticides and repellents taking into account the possible impact to human health of these products and giving priority to natural prod- ucts and the less harming options. Gang violence context in El Salvador could be a handicap to an intervention. The gangsters threaten the population of the communities and blackmail them. As shown by UNDP fear makes the inhabitants of the community distrust on each other and, therefore it is difficult to promote any intervention in the communities, especially among young people.
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Applicability of citronella oil (<I>Cymbopogon winteratus</I>) for the prevention of mosquito-borne diseases in the rural area of Tikapur, far-western Nepal

Applicability of citronella oil (<I>Cymbopogon winteratus</I>) for the prevention of mosquito-borne diseases in the rural area of Tikapur, far-western Nepal

Methods: A repellency activity test was performed with 100% citronella oil (Cymbopogon winteratus) from April to May 2013 in the Tikapur Municipality of the Kailali district, Nepal. The test was divided into two trials: an indoor exposure (IE) test (N=101) and an outdoor exposure (OE) test (N=140) from 5.00 pm to 7.00 pm. Each trial contained an experimental citronella oil-applied group and a non-applied (control) group. The outcome measures were the protective effect of citronella oil against mosquitoes, the number of mosquito bites, the repellency percentage, the smell satisfaction and the irritation level.
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Flooding in Townsville, north Queensland, Australia, in February 2019 and its effects on mosquito-borne diseases

Flooding in Townsville, north Queensland, Australia, in February 2019 and its effects on mosquito-borne diseases

In Townsville, Ross River virus disease (RRV), Barmah Forest virus (BFV) disease, and dengue are the prevalent mosquito-borne diseases [2]. The Aedes and Culex mosquito populations are predominant in this area. While Aedes mosquitoes breed in fresh stagnant water in and around the dwellings or in marshlands, Culex population grow in poorly kept sewerage, and farms or irrigated fields with water left standing for several days [3,4]. The role of flooding on the increased occurrence of dengue, BFV disease, and RRV disease in the context of Townsville is arguable. Previous studies have found a significant association between incidence of flooding and upsurge of infectious diseases [5–9]. While flash flooding initially disturbs the mosquito habitat, this may or may not subsequently increase the occurrence of mosquito populations and MBDs in the flood-affected communities [8,10,11]. This will depend on the specific MBD we are concerned about and its local endemicity. If it is dengue, which is primarily transmitted locally from imported cases, this is less likely. Other than the returnees from overseas, especially those from the Southern Hemisphere, where dengue season is currently occurring, the current flooding scenario in Townsville will attract very few tourists who could bring the disease with them. However, in considering flooding events in tropical settings in other parts of the world, a positive association has been observed between river level and dengue incidence [10].
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A quantitative risk assessment approach for mosquito borne diseases: malaria re emergence in southern France

A quantitative risk assessment approach for mosquito borne diseases: malaria re emergence in southern France

Vulnerability is related to gametocyte carriers as the game- tocyte is the stage transmissible to mosquitoes. Neverthe- less, very little is known about gametocyte carriers, and any information must be considered in the context of imported malaria cases, i.e. taking account of the fact that the illness is diagnosed and treated. Since anti malarial- treatment in France is generally conducted with drugs that do not prevent gametocyte emergence [8], an assumption that every patient may develop some gametocytes was made. Hence, we used imported malaria cases to approach the gametocyte presence in the Camargue. Data relative to imported malaria cases were obtained from five public hospitals localized in important towns in/around the Camargue (Montpellier, Nîmes, Avignon, Arles and Marseille). These data were analysed with regard to the date, Plasmodium species, patients' residence for the 2004–2005 period and contamination place.
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Climate change and mosquito-borne diseases in China: a review

Climate change and mosquito-borne diseases in China: a review

humidity [96]. Studies in different areas of Asia have also shown the likely influence of climate on the incidence of JE [97-99]. However, little research has been conducted to examine the effect of climatic variables, along with mass vaccination and other non-climatic drivers in China. Bi et al. (2007) have identified positive relationships be- tween climatic variables (monthly maximum temperature, minimum temperature and total rainfall) and JE transmis- sion in a rural region of Anhui Province [65] and a metro- politan area of Shangdong Province [63] where no rice was grown and the role of pigs in disease transmission was not fully understood [63]. Unfortunately, the effects of vaccination on JE control in the two areas were very limited during the study periods. In the metropolitan area of Jinan city, a potential threshold of the effect of temperature on JE was also detected by the Hockey Stick model which is based on the assumption that temperature has no effect on JE cases until a threshold value. When the monthly mean maximum temperature was higher 25.2°C or the minimum temperature was over 21.0°C, an obvious increase in JE cases occurred [63]. These findings are consistent with the threshold temperature detection in previous Chinese studies [87]. Using ARIMA models, Lin et al. (2011) suggested that monthly average temperature and relative humidity at 0-month lag were positively associated with JE incidence in Linyi, another city of Shangdong Province after adjusting for mass vaccination in this area [62]. Time lag-0 of climate variables was per- haps because the behaviour of pig breeding in Linyi, along with the high density of mosquitoes help to shorten the transmission cycle [62]. With adjustment of more inter- actional factors including seasonal pattern, time trend, pig density, 23 geographic areas representing location of farm and paddy cultivation, and vaccination coverage, HSU et al. (2008) identified the significant effects of monthly temperature and rainfall with two months lag on the monthly occurrence of JE in Taiwan [64]. Similarly, temperature and rainfall were two significant determi- nants of JE spread with control of vaccination coverage and paddy field areas [71].
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The impact of maturation delay of mosquitoes on mosquito-borne disease transmission

The impact of maturation delay of mosquitoes on mosquito-borne disease transmission

In order to control these diseases, it is essential to understand the mosquito population dy- namics first and then to consider how resource and temperature can affect mosquito population, and how they in turn can affect mosquito-borne disease transmission. Since only the adult fe- male mosquitoes are responsible for transmitting diseases, therefore in general, models focus only on describing the dynamics of adult female mosquitoes. There have been extensive dynam- ical modeling studies of the mosquito population and mosquito-borne diseases. In [1, 5, 12, 19] West Nile virus transmission dynamics has been considered. In [3, 13, 14, 17, 18], malaria transmission dynamics has been considered. In [6, 7, 15, 16], dengue transmission dynamic- s have been studied. In [2], Bolzoni et al. studied the role of heterogeneity on the invasion probability of mosquito-borne diseases in multi-host models.
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Engineering the control of mosquito borne infectious diseases

Engineering the control of mosquito borne infectious diseases

For the implementation of population replacement strategies aimed at curbing mosquito-borne diseases, the anti-pathogen constructs described above need to be driven genetically through natural populations so that the disease refractory traits will spread (Figure 2h). A number of artificial gene-drive systems capable of forcing their own spread in a non-Mendelian manner are being developed that could be used for this purpose. In the model organism Drosophila melanogaster , the first gene-drive mechanism was developed on the basis of a toxin-antidote system [59]. This synthetic system, named Medea after the mythological figure of the woman who killed her own children to take revenge on her husband’s betrayal, is based on expression in the zygote of a toxic gene, such as a microRNA against a maternal mRNA essential for embryonic development [59,60]. Transgenic females carry an ‘antidote’, that is, an allele of the gene that is insensitive to the toxin, allowing transgenic progeny to survive and spread the transgene. Although Medea has yet to be adapted to disease vectors, HEG-based technologies have been suggested and tested as gene drives in mosquitoes [36,61]. In this system, the drive encodes DNA-cutting machinery that cleaves a wild-type target locus from a transgene located at the homologous locus. Repair of the DNA break by homologous recombination causes the transgene to copy into the cleaved locus, causing a hemizygous cell to become homozygous for the transgene (Figure 2h). If this mechanism occurs in the germline, the transgene can spread through the population, potentially carrying an anti-pathogenic construct with it. Proof-of-principle use of HEGs to facilitate gene-drive mechanisms in An. gambiae was based on the I-SceI enzyme, which targeted its own recognition sequence that had been artificially introduced into a GFP reporter gene [36]. Homing of the HEG into its target sequence, pre- viously integrated into the mosquito genome, would there- fore generate GFP null mutants. Small cage experiments
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ERADICATION OF MOSQUITO BORNE DISEASES BY ENTOMOPATHOGENIC FUNGI

ERADICATION OF MOSQUITO BORNE DISEASES BY ENTOMOPATHOGENIC FUNGI

www.wjpr.net Vol 6, Issue 8, 2017. 1443 eradicate the transmission of these diseases they have certain considerable drawbacks. [5] These chemical agents have been known to cause allergic reactions in some [6] and are simply harmful to others are the drawbacks associated with humans, while other drawbacks include resistance in vector population, environmental pollution and cost. [7] Use of entomopathogenic fungi as a larvicide is a very safe and promising alternative to these perilous modes of control of spread of mosquitoes [8,9,10] Moreover it arrests the growth of these nuisance causing agents at their initial ages i.e. in their larval stage. These fungi tend to be host specific and provide the ease of their availability at large scale.
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Biological control of mosquito-borne viral diseases: Prospects and challenges

Biological control of mosquito-borne viral diseases: Prospects and challenges

St. Louis encephalitis (SLE) virus spreads naturally in birds. Birds are the natural reservoirs. These viruses are transmitted by Culex mosquitoes. Humans become infected only when bitten by an infected mosquito. Humans are actually “dead end” hosts, implying that the virus in human blood at no time reaches a level significant enough to infect a biting female mosquito to continue the infectious cycle. Not all people infected with the virus show and develop clinical disease. However, the virus may produce sudden onset of nausea, fever, vomiting, and severe headache in individuals within 5–7 days after being bitten [25]. Fatality rates range from 2–20% with most mortalities occurring in older subjects. Sporadic outbreaks of St. Louis encephalitis usually happen in mid-summertime to early fall. Since domestic fowls and wild birds are the reservoirs of this virus, municipal areas where large bird populace and abundant Culex mosquitoes are found together are major sites for a disease outbreak [25].
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The importance of human population characteristics in modeling Aedes aegypti distributions and assessing risk of mosquito-borne infectious diseases

The importance of human population characteristics in modeling Aedes aegypti distributions and assessing risk of mosquito-borne infectious diseases

mosquito-borne illnesses. A high probability of suitabil- ity in these maps still does not guarantee species pres- ence, but it does show that there is a high likelihood that the combination of ideal climatic conditions and human population characteristics provides suitable conditions for feeding and breeding. In many of the northern states within the study region (e.g., Kentucky, Tennessee, Oklahoma), occurrences of Ae. aegypti have thus far been minimal, but models indicate that many elements of a suitable habitat, and consequently a higher risk of mosquito-borne illnesses, are present, especially in the larger urban environments. Long-term changes in climate in these regions may result in an increased risk to mosquito-borne illnesses as mosquitoes establish pop- ulations at higher latitudes [4].
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A global assembly of adult female mosquito mark release recapture data to inform the control of mosquito borne pathogens

A global assembly of adult female mosquito mark release recapture data to inform the control of mosquito borne pathogens

Mosquitoes are important vectors of viruses and parasites of human, veterinary and wildlife health concern [1]. Major mosquito-borne infectious diseases of humans in- clude malaria, dengue, filariasis, chikungunya fever, Rift Valley fever and the arboviral encephalitides, including Japanese encephalitis and West Nile neuroinvasive viral disease. Infections can cause high morbidity and mortality and are of great public health concern in endemic areas. Globally, malaria parallels HIV/AIDS and is slightly be- hind diarrhoeal disease in terms of disability-adjusted life years lost [2]. The current estimated global burden of den- gue is higher (390 million infections per year) than previ- ously appreciated [3] and will likely increase as the range of Aedes expands [4,5] and as humans are increasingly concentrated in high risk urban areas [6]. Lymphatic filar- iasis often leads to permanent disability and its global bur- den ranks high amongst other neglected tropical diseases [2]. West Nile virus is the most widespread mosquito- borne neuropathogen and has dramatically expanded its geographic range across the Western Hemisphere after its introduction into North America in 1999 [7].
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Control of Vector-Borne Human Parasitic Diseases

Control of Vector-Borne Human Parasitic Diseases

Vector-borne diseases (VBD) transmitted by arthropods are responsible for over 1 billion cases and 1 million deaths every year, corresponding to at least 17% of all infectious diseases in human populations [1]. Among them, we can find malaria, leishmaniasis, onchocerciasis, lymphatic filariasis, Chagas disease, and African trypanosomiases, as well as several arboviral diseases (arthropod-borne virus) such as dengue and Zika virus. Some of these have reemerged in new parts of the world and have become a topic of growing importance in public health and in political and scientific agendas [2]. Several factors are contributing towards the reemergence of VBDs. On the one hand, the spread of resistance to drugs in pathogens has become a major obstacle for the effective treatment of some VBDs [3], and the emergence of new strains of arboviruses (e.g., Zika virus in Brazil) has created new challenges for health care systems [4]. On the other hand, an increase in insecticide resistance is threatening the sustainability of vector control programmes in several tropical regions [5]. Additionally, the expansion of different vector populations due to climate change is becoming a grow- ing concern in temperate countries, where vector control programs have been discontinuous for almost 50 years [6, 7]. The scientific community has been trying to overcome these
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SEIR Model and Simulation for Vector Borne Diseases

SEIR Model and Simulation for Vector Borne Diseases

This theory is further applied to a vector borne disease namely malaria. SEIR model is formulated for both human as well as for vector population. Analysis is done for the combined effect of both the populations when the ma- laria is in epidemic state.

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Mosquito borne heartworm Dirofilaria immitis in dogs from Australia

Mosquito borne heartworm Dirofilaria immitis in dogs from Australia

Dirofilaria immitis (canine heartworm) is a parasitic nematode responsible for the canine heartworm disease. Transmitted from host-to-host via mosquito bites, infec- tion largely affects the cardiopulmonary system resulting in severe and potentially fatal disease. The disease is well- established, mostly affecting temperate, tropical and subtropical areas of North, Central and South America, southern Europe, as well as Australia [1–7]. The preva- lence of the disease is influenced by climate and topog- raphy, but most importantly, by the presence of mosquito vectors - ubiquitous Culex spp., Aedes spp. and Anopheles spp. [6, 8]. Transmission occurs when mosquitoes ingest D. immitis microfilariae (L1) as they circulate the blood of infected animals. In the mosquito, the microfilariae moult before migrating to the proboscis as D. immitis infective third-stage larvae (L3) [9]. These larvae (L3) are trans- ferred to hosts during blood meals, where migrate throughout the blood and body towards the pulmonary arteries and reach sexual maturity in large blood vessels [10]. The microfilariae are first seen in 6–7 month after the initial infection and the life span of adult female (230– 310 mm in length) and male (120–190 mm in length) heartworms is 5–10 years [8–10].
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Protein Kinase G Phosphorylates Mosquito-Borne Flavivirus NS5

Protein Kinase G Phosphorylates Mosquito-Borne Flavivirus NS5

Replacement of Thr with His polymorphism from tick-borne flaviviruses rendered the DENV replicon nonfunctional. To determine the importance of Thr449, the DENV subgenomic replicon was engineered to replace the threonine in the CXTC motif with a serine, histidine, or a glutamic acid. The positively charged mutant histidine that naturally occurs in tick-borne viruses rendered the DENV replicon nonfunctional. Replace- ment of threonine with glutamic acid (a negatively charged residue which may mimic the effect of a nonreversible phos- phorylation event) also significantly impaired DENV replicon replication (Fig. 8). However, the efficiency of replication from the DENV replicon containing the serine mutant was almost as high as that from the threonine-containing wild type. FIG. 7. Logo analysis of ⬎ 700 flaviviral genomes separated by transmission vector. (A) Mosquito-borne flavivirus NS5 sequences were aligned, and logo analysis was performed by selecting 12 amino acids around the phosphorylation site of interest. The asterisk indicates position 449 in DENV or position 450 in YFV, which is highly conserved with either threonine (T) or serine (S), respectively, among all mosquito-borne flaviviruses. (B) Twenty-six tick-borne flavivirus NS5 sequences were aligned, and logo analysis was performed for the amino acids around the residue of interest (asterisk).
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Aedes Mosquitoes and Aedes Borne Arboviruses in Africa: Current and Future Threats

Aedes Mosquitoes and Aedes Borne Arboviruses in Africa: Current and Future Threats

Over 60 years ago, and with considerable prescience, Mahaffy [118] argued the case for eradication of Ae. aegypti from Africa, writing: “A successful eradication programme of this nature carries with it results of such profound importance, not only to Africa, but also to infectible territories outside Africa, that it is impossible to over-emphasize the necessity for its initiation at the earliest possible moment”. Most would agree that the prospect for elimination of Ae. aegypti from Africa is not a realistic one at present, but that the need to reverse decades of neglect of arboviral disease in Africa is long overdue. To build an appropriate evidence base on which disease prevention and control strategies and policies can be founded, we recommend the following topics be prioritized for investigation: distribution of cases of dengue, chikungunya, Zika and other arboviruses in humans; distributions of Ae. aegypti and Ae. albopictus in Africa; updated characterization and distribution of insecticide resistance in Ae. aegypti and Ae. albopictus, with broader geographical coverage using standardized methodologies; development of context-specific Aedes-borne arboviral disease surveillance plans, and of outbreak prevention and vector control response strategies.
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