Insect-transmitted Diseases Research Articles

Insect immunity in the Anthropocene.

Anthropogenic activities result in global change, including climate change, landscape degradation and pollution, that can alter insect physiology and immune defences. These changes may have contributed to global insect decline and the dynamics of insect-transmitted diseases. The ability of insects to mount immune responses upon infection is crucial for defence against pathogens and parasites. Suppressed immune defences reduce fitness by causing disease-driven mortality and elevated immune responses reduce energy available to invest in other fitness traits such as reproduction. Understanding the impact of anthropogenic factors on insect-pathogen interactions is therefore key to determining the contribution of anthropogenic global change to pathogen-driven global insect decline and the emergence and transmission of insect-borne diseases. Here, we synthesise evidence of the impact of anthropogenic factors on insect immunity. We found evidence that anthropogenic factors, such as insecticides and heavy metals, directly impacting insect immune responses by inhibiting immune activation pathways. Alternatively, factors such as global warming, heatwaves, elevated CO2 and landscape degradation can indirectly reduce insect immune responses via reducing the energy available for immune function. We further review how anthropogenic factors impact pathogen clearance and contribute to an increase in vector-borne diseases. We discuss the fitness cost of anthropogenic factors via pathogen-driven mortality and reduced reproductive output and how this can contribute to species extinction. We found that most research has determined the impact of a single anthropogenic factor on insect immune responses or pathogen resistance. We recommend studying the combined impact of multiple stressors on immune response and pathogen resistance to understand better how anthropogenic factors affect insect immunity. We conclude by highlighting the importance of initiatives to mitigate the impact of anthropogenic factors on insect immunity, to reduce the spread of vector-borne diseases, and to protect vulnerable ecosystems from emerging diseases.

Loss-of-function in testis-specific serine/threonine protein kinase triggers male infertility in an invasive moth

Genetic biocontrol technologies present promising and eco-friendly strategies for the management of pest and insect-transmitted diseases. Although considerable advancements achieve in gene drive applications targeting mosquitoes, endeavors to combat agricultural pests have been somewhat restricted. Here, we identify that the testis-specific serine/threonine kinases (TSSKs) family is uniquely expressed in the testes of Cydia pomonella, a prominent global invasive species. We further generated male moths with disrupted the expression of TSSKs and those with TSSKs disrupted using RNA interference and CRISPR/Cas9 genetic editing techniques, resulting in significant disruptions in spermiogenesis, decreased sperm motility, and hindered development of eggs. Further explorations into the underlying post-transcriptional regulatory mechanisms reveales the involvement of lnc117962 as a competing endogenous RNA (ceRNA) for miR-3960, thereby regulating TSSKs. Notably, orchard trials demonstrates that the release of male strains can effectively suppress population growth. Our findings indicate that targeting TSSKs could serve as a feasible avenue for managing C. pomonella populations, offering significant insights and potential strategies for controlling invasive pests through genetic sterile insect technique (gSIT) technology.

Impact of Climate Change on Pest Biology, Behaviour and Their Distributions

Increased temperatures, rising CO2 levels, and changing precipitation patterns are influencing agricultural production. These changes can lead to the expansion of insect pests geographic distribution, increased survival during overwintering, more generations per year, altered synchrony with plants, changed interspecific interactions, higher risk of invasion by migratory pests, increased incidence of insect-transmitted plant diseases, and reduced effectiveness of biological control. There is a serious risk of economic losses in crop production. Human food security is challenged due to potential disruptions in agricultural systems. Climate change necessitates adaptive management strategies to address evolving pest dynamics. Future research should focus on developing modified integrated pest management tactics to cope with changing pest statuses. Monitoring climate and pest populations is crucial for understanding and predicting the impact of climate change on insect pests. This review examines the climate change effect on insect pest biology and behavior and explores the potential use of modern pest monitoring technologies, modeling prediction tools can aid in forecasting and planning for potential pest outbreaks. Integrated pest management (IPM) approaches should be adapted to incorporate the changing dynamics influenced by climate change. This may involve a combination of chemical, biological, cultural, and mechanical control methods.

Dichlorodiphenyltrichloroethane for Malaria and Agricultural Uses and Its Impacts on Human Health.

Pesticides are widely used in agriculture and disease control, and dichlorodiphenyltrichloroethane (DDT) is one of the most used pesticides in human history. Besides its significant contributions in pest control in agriculture, DDT was credited as having saved millions of human lives for controlling malaria and other deadly insect-transmitted diseases. Even today, the use of DDT in some countries for malaria control cannot be replaced without endangering people who live there. The recent COVID-19 pandemic has changed our lives and reminded us of the challenges in dealing with infectious diseases, especially deadly ones including malaria. However, DDT and its metabolites are stable, persist long, are found in almost every corner of the world, and their persistent effects on humans, animals, and the environment must be seriously considered. This review will focus on the history of DDT use for agriculture and malaria control, the pathways for the spread of DDT, benefits and risks of DDT use, DDT exposure to animals, humans, and the environment, and the associated human health risks. These knowledge and findings of DDT will benefit the selection and management of pesticides worldwide.

History and Assessment of the War Environment on the Subsequent Health of the Vietnam Veteran

In January 1962, the first Allied combat, combat advisory, and support forces arrived in South Vietnam. By the end of the War, almost 3 million allied personnel had been engaged in this violent Conflict. Six nations provided the Allied Military Forces to support the Republic of South Vietnam from 1965 through March of 1973. The tropical environment posed many challenges to the Allied Military Forces in waging a war against an elusive enemy who had a history of fighting in such an environment. Most Allied combat units spent weeks in the brush enduring the inhospitable environment that included an invisible but deadly enemy. For those soldiers living in outposts or isolated bases or airfields, the constant enemy shelling deprived them of sleep, leaving them exhausted, disoriented, and too often contentious and increasingly depressed. Beyond the possibilities of injury and death during combat, military personnel were exposed to diverse agents and environments that may have affected their health, and thus caused injury and disease while in service or after discharge. Indeed, insect-transmitted diseases and other health related issues accounted for more casualties then did enemy bullets and bombs. Many of those exposures reflected the diverse tasks and functions of military personnel serving in unfamiliar environments associated with combat operations. Fifty health studies of Vietnam veterans by four of the Allied Nations confirmed that with two exceptions, no Vietnam veterans were ever exposed to Agent Orange. What the health studies did confirm was the impact of the “Vietnam Experience” on the long-term health of the men and women who served in the Vietnam War.

Effects of global warming on insect behaviour in agriculture

Global warming and climate change are some of the most widely discussed topics in today's society, and they are of considerable importance to agriculture globally. Climate change directly affects agricultural production. On the other hand, the agricultural sector is inherently sensitive to climate conditions, and this has made the agricultural sector one of the most vulnerable sectors to the effects of global climate change. Rising CO2 levels in the atmosphere, increased temperature, and altering precipitation patterns all substantially influence agricultural insect pests and agricultural productivity. Climate change has a number of implications for insect pests. They can lead to a decreased biological control effectiveness, particularly natural enemies, increased incidence of insect-transmitted plant diseases, increased risk of migratory pest invasion, altered interspecific interaction, altered synchrony between plants and pests, increase in the number of generations, increased overwintering survival, and increase in geographic distribution. As a consequence, agricultural economic losses are a real possibility, as is a threat to human food and nutrition security. Global warming will necessitate sustainable management techniques to cope with the altering state of pests, as it is a primary driver of pest population dynamics. Future studies on the impacts of climate change on agricultural insect pests might be prioritized in several ways. Enhanced integrated pest control strategies, the use of modelling prediction tools, and climate and pest population monitoring are only a few examples.

Larvicidal Activity of Leucas Aspera Against the Larvae of Anopheles, Aedes Aegypti and Culex Quinquefasciatus

Abstract: Insect-transmitted diseases cause high morbidity however they additionally embody deadly diseases that cause high mortality rates among infected individuals.Many two-winged insects species such as Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus act as vectors. Ae. aegypti, acts as a vector for yellow fever, dengue and chikungunya. Aedes aegypti is cosmopolitan within the tropical and semitropical zones. Anopheles stephensi is the primary vector of malaria in India and other west Asian countries. C. quinquefasciatus is a vector of lymphatic filariasis which is one of the widely distributed tropical diseases with around 120 million people infected worldwide. The mosquitocidal activity was analyzed by aqueous, ethanol and methanol extract of Leucas aspera plant extract against the malaria, yellow fever and dengue causing Ae.aegypti, An.stephensi. Leucas aspera is well known to possess various pharmacological activities like antifungal, antimicrobial and cytotoxic activities. Leaves of this plant are applied to treat snake bites. The result was supported by probit analyses was carried out for twenty fourth and forty eighth hour methyl alcohol extracts of L. aspera. The data showed profound larvicidal activity with methyl alcohol extract compared with the other extracts. Keywords: Vector control, L. aspera, Ae.a.egypti, An. stephensi, Culex quinquefasciatus.

The Impact of Climate Change on Agricultural Insect Pests.

Simple SummaryClimate change and extreme weather events have a major impact on crop production and agricultural pests. As generally adaptable organisms, insect pests respond differently to different causes of climate change. In this review, we address the effects of rising temperatures and atmospheric CO2 levels, as well as changing precipitation patterns, on agricultural insect pests. Since temperature is the most important environmental factor affecting insect population dynamics, it is expected that global climate warming could trigger an expansion of their geographic range, increased overwintering survival, increased number of generations, increased risk of invasive insect species and insect-transmitted plant diseases, as well as changes in their interaction with host plants and natural enemies. As climate change exacerbates the pest problem, there is a great need for future pest management strategies. These include monitoring climate and pest populations, modified integrated pest management strategies, and the use of modelling prediction tools which are presented here.Climate change and global warming are of great concern to agriculture worldwide and are among the most discussed issues in today’s society. Climate parameters such as increased temperatures, rising atmospheric CO2 levels, and changing precipitation patterns have significant impacts on agricultural production and on agricultural insect pests. Changes in climate can affect insect pests in several ways. They can result in an expansion of their geographic distribution, increased survival during overwintering, increased number of generations, altered synchrony between plants and pests, altered interspecific interaction, increased risk of invasion by migratory pests, increased incidence of insect-transmitted plant diseases, and reduced effectiveness of biological control, especially natural enemies. As a result, there is a serious risk of crop economic losses, as well as a challenge to human food security. As a major driver of pest population dynamics, climate change will require adaptive management strategies to deal with the changing status of pests. Several priorities can be identified for future research on the effects of climatic changes on agricultural insect pests. These include modified integrated pest management tactics, monitoring climate and pest populations, and the use of modelling prediction tools.

Evaluation of barrier plants for the cultural control of tomato yellow leaf curl disease

Abstract Barrier cropping plays an essential role in controlling insect pests and insect-transmitted diseases in cultural control. It has been proven efficient in suppressing the spread of nonpersistently transmitted viruses. For suppressing the spread of persistently transmitted viruses, barrier cropping is not considered an effective control strategy because barrier plants cannot act as a virus sink to purge the virus in the vector. However, few successful cases of barrier cropping suppressing the spread of persistently transmitted viruses have been reported. The objectives of the present study were to screen candidates (cucumber, okra, Chinese kale, soybean, and corn) for potential barrier plants to control tomato yellow leaf curl Thailand virus (TYLCTHV) and examine whether prefeeding on these plants can reduce the virus titer in its vector, Bemisia tabaci, thus reducing TYLCTHV transmission. The results revealed that nonviruliferous whiteflies preferred cucumber and okra to tomato, whereas viruliferous whiteflies preferred cucumber to tomato. Although prefeeding on cucumber, okra, and Chinese kale did not reduce the titer of TYLCTHV in viruliferous whiteflies, the vector transmission rate decreased after the whiteflies fed on Chinese kale. It implies that planting Chinese kale as a barrier plant for tomato cultivation may reduce the incidence of TYLCTHV. In addition, the preference to cucumber plants may reduce the incidence of whiteflies acquiring TYLCTHV from virus-infected tomato plants and of viruliferous whiteflies inoculating the virus into healthy tomato plants, thereby reducing the disease incidence. Further field trials of barrier cropping using the candidate plants are warranted.

Insects That Feed on Faba Bean in Southern Florida

The information provided in this document is the result of a two-year study to document insects and insect-transmitted diseases that may have to be considered as pests to this potential crop for Florida (Figure 1). This list of plant and insect feeders will also serve as a reference to help growers, scouts and home gardeners determine which insects they may find on faba beans. This document is ENY-703, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date: August 2005.

The Epidemiology of Xylella fastidiosa; A Perspective on Current Knowledge and Framework to Investigate Plant Host-Vector-Pathogen Interactions.

Insect-transmitted plant diseases caused by viruses, phytoplasmas, and bacteria share many features in common regardless of the causal agent. This perspective aims to show how a model framework, developed originally for plant virus diseases, can be modified for the case of diseases incited by Xylella fastidiosa. In particular, the model framework enables the specification of a simple but quite general invasion criterion defined in terms of key plant, pathogen, and vector parameters and, importantly, their interactions, which determine whether or not an incursion or isolated outbreak of a pathogen will lead to establishment, persistence, and subsequent epidemic development. Hence, this approach is applicable to the wide range of X. fastidiosa-incited diseases that have recently emerged in southern Europe, each with differing host plant, pathogen subspecies, and vector identities. Of particular importance are parameters relating to vector abundance and activity, transmission characteristics, and behavior in relation to preferences for host infection status. Some gaps in knowledge with regard to the developing situation in Europe are noted.

Phytochemical screening and insecticidal activity of different extracts of Acacia modesta Wall. on adult Culex pipiens mosquito.

Background: Insect-transmitted diseases remain a major source of illness and death worldwide. Mosquitoes alone transmit diseases in more than 700 million people annually. The aim of the work: is to perform phytochemical screening tests and to investigate the insecticidal effects of different extracts of the aerial parts of Acacia modesta (A. modesta) Wall. on adult Culex pipiens (Cx. pipiens) mosquito. Materials and methods: Different A. modesta Wall. extracts were bioassayed against adult Cx. Pipiens mosquito to estimate their insecticidal effects. Three different extracts of A. modesta Wall. aerial parts were prepared (distilled water, ethanol and acetone extracts). Different concentration for each prepared extract were tested for their insecticidal activity as well as different duration of exposure e.g. one hour, 24 hours, 48 hours and 72 hours were also performed. Results: The efficacy of these extracts varies according to type of solvent used, concentration of extract and duration of exposure. With continuous exposure for 24 hrs; efficacy of A. modesta Wall. extract was elevated from 62–91% in the same manner. Expanding the exposure for 48 hrs; show continuous elevation up to 90–100 %. Meanwhile, the highest concentration of the tested plant extracted in acetone is one third (100 mg/ml) compared to other solvents (300 mg/ml), results showed that using acetone as a solvent is better than either distilled water or ethanol for its insecticidal activity. Conclusion: It was evident from the results that the plant is a potential source of botanical insecticides against adult Cx. pipiens mosquitoes and their toxic effects are time and concentration dependent. Moreover, phytochemical screening for the aerial parts of A. modesta Wall. resulted in the identification of carbohydrates and/or glycosides, tannins, flavonoids , unsaturated sterols and/or triterpens as well as saponins.

Factors influencing the efficacy of insect-proof screens

The use of insect-proof screens as a method of control is widespread. These agrotextiles act as physical barriers preventing the contact between insects and plants. Their effectiveness as a method of crop protection has been sufficiently demonstrated. The use of insect-proof screens reduces pest populations, decreases the incidence of insect-transmitted diseases and as a result it reduces the need to apply pesticides. There is a wide variety of screens with different properties on the market. Some of these agrotextiles are known commercially like anti-aphids or anti-thrips screens although their efficacy is not proven. During the last decades different studies have evaluated the efficacy of insect exclusion screens both under laboratory and in field conditions against various pests. The results of these works offer constant values that represent the relationship between insects and fabrics. However, that relationship is not a constant and depends on other variables in addition to the properties of the textile and the characteristics of the insect. The velocity and air temperature also influence the relationship between screen and insect and modify the exclusion capacity of the protection screens. To take into account these variables, we have built a device to evaluate the effectiveness of the screens under laboratory conditions. With this device we can measure the capacity of exclusion of the screens at different air velocities and we can interpret the data according to the measured temperature values. The results show that the efficacy of the screens varies when the conditions change and, in general, the exclusion percentage of the screens decreases when air velocity increases. The temperature is also an influential variable on the efficacy of these textiles and it has been observed that if the temperature decreases the effectiveness of the screens increases due to the lower activity of insects.

Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings.

Toxicity and Carcinogenicity of Dichlorodiphenyltrichloroethane (DDT).

Dichlorodiphenyltrichloroethane (DDT) is still used in certain areas of tropics and subtropics to control malaria and other insect-transmitted diseases. DDT and its metabolites have been extensively studied for their toxicity and carcinogenicity in animals and humans and shown to have an endocrine disrupting potential affecting reproductive system although the effects may vary among animal species in correlation with exposure levels. Epidemiologic studies revealed either positive or negative associations between exposure to DDT and tumor development, but there has been no clear evidence that DDT causes cancer in humans. In experimental animals, tumor induction by DDT has been shown in the liver, lung, and adrenals. The mechanisms of hepatic tumor development by DDT have been studied in rats and mice. DDT is known as a non-genotoxic hepatocarcinogen and has been shown to induce microsomal enzymes through activation of constitutive androstane receptor (CAR) and to inhibit gap junctional intercellular communication (GJIC) in the rodent liver. The results from our previously conducted 4-week and 2-year feeding studies of p,p′-DDT in F344 rats indicate that DDT may induce hepatocellular eosinophilic foci as a result of oxidative DNA damage and leads them to hepatic neoplasia in combination with its mitogenic activity and inhibitory effect on GJIC. Oxidative stress could be a key factor in hepatocarcinogenesis by DDT.

The Big Muddy: An Environmental History of the Mississippi and Its Peoples from Hernando de Soto to Hurricane Katrina by Christopher Morris

The Big Muddy: An Environmental History of the Mississippi and Its Peoples from Hernando de Soto to Hurricane Katrina. By Christopher Morris. (New York and other cities: Oxford University Press, 2012. Pp. xiv, 300. $36.95, ISBN 978-0-19-531691-9.) On the first page of his ambitious and highly entertaining The Big Muddy: An Environmental History of the Mississippi and Its Peoples from Hernando de Soto to Hurricane Katrina, Christopher Morris divides the Mississippi River Valley into two categories: the and the dry. The wet valley is the natural formation created by the mighty river, while the dry has been constructed--with varying degrees of success--on the original wet one by people of mainly European ancestry in their foolhardy attempt to interrupt many of the river's endemic processes, the most important of which is the nearly annual flooding. The Mississippi basin is, however, customarily divided into the upper and valleys, with the confluence of the Ohio and Mississippi Rivers serving as the traditional boundary between them. Contrary to the promise of the book's subtitle (and presumably to the disappointment of many readers), the environmental history of only the lower(most) Mississippi Valley is addressed in any depth. Morris pays the bulk of his attention to the area covered by the present-day state of Louisiana and to the river's estuary, with occasional forays into the Mississippi and Arkansas bottomlands. Of course, a comprehensive environmental history of the whole Mississippi Valley in 224 pages of text would be a tall order. Considering the magnitude of his project for even the lower Mississippi Valley, Morris copes admirably. The first five chapters examine the lower Mississippi floodplain in its natural condition and the various ways Native Americans and early Spanish and French settlers adapted--or tried to adapt--to the damp landscape. Chapters 6-8 describe the construction of a massive levee system that transformed the region into a prime agricultural area as a part of the United States during the nineteenth century. Relief from flooding made the development of European-style agriculture and infrastructure possible, but only at great environmental cost and with unanticipated consequences. The last three chapters of the book examine, among other topics, the pathological landscape of pesticides, herbicides, and insect-transmitted diseases; the role of aquaculture; and nature's return in the form of Hurricane Katrina, together constructing an unusually powerful argument for the more sustainable use of the floodplain in the future (pp. …

Preference of Bemisia tabaci biotype B on zucchini squash and buckwheat and the effect of Delphastus catalinae on whitefly populations.

Zucchini squash, Cucurbita pepo L., is an important vegetable crop in Florida. Physiological disorders and insect-transmitted diseases are major problems for squash growers in semi-tropical regions around the world. Bemisia tabaci (Gennadius) biotype B is a significant whitefly pest and is largely responsible for transmitting viruses and causing physiological disorders in squash. Several studies have shown that whitefly populations are reduced when crops are interplanted with non-host cover crops or mulches. The aim of the present study was to determine how the presence of buckwheat, Fagopyrum esculentum Moench, and a key predator, Delphastus catalinae (Horn), affect whitefly colonization on squash. Whitefly densities were higher on squash than on buckwheat. The introduction of D. catalinae on squash significantly reduced whitefly populations. Overall, there were higher densities of D. catalinae on squash where the whitefly pest was more concentrated compared with buckwheat. The study provided preliminary evidence that D. catalinae, when used in conjunction with buckwheat as a living mulch, may aid in reducing whiteflies in squash. This greenhouse experiment highlights the need to investigate a multitactic approach of intercropping buckwheat with squash and the incorporation of D. catalinae in the field to manage populations of whiteflies and whitefly-transmitted diseases. © 2015 Society of Chemical Industry.

Variations of Incidence, Types of Virus Diseases and Insect Vector Populations of Tomato (Solanum lycopersicum L.), Grown in Different Agroecological Regions of Sri Lanka under Two Crop Management Systems

Incidence and types of insect-transmitted virus diseases of plants vary with the environmental factors, which have direct or indirect relationships on population dynamics of vectors. Alternative indirect strategies are essential to mitigate the environmental and health hazards of pesticide usage, which is the most predominant method of vector management used at present. The present study was conducted to determine the variation of virus disease incidence and the population of insect vectors in field grown tomato (Solanum lycopersicum L.) cv. Thilina in different environmental conditions using two crop management systems namely, existing management system with pesticide applications and an integrated management package (IMP) with less reliance on pesticides. Incidence and types of virus diseases, their abundance and types of both insect vectors and beneficial insects were recorded over one cropping season, together with mean day temperature and rainfall data. Peroxidase activity in tomato tissues was quantified spectrophotometrically to determine the effects of the location and management practices on build-up of defence related enzymes in plant tissues. Relationships between the virus disease incidence, vector and beneficial insect populations and climatic parameters were also analyzed. Results revealed that there was no significant (p=0.05) difference between the two types of management systems in terms of virus disease incidence indicating the equal efficiency of the tested IMP treatment and existing pest control method on virus disease management. Abundance of insect vectors and beneficial insect populations were significantly (p0.05) influenced by the interaction effect of the management system and location. The mean day temperature was weakly related with the virus disease incidence at different locations. Peroxidase activity of tomato tissues was significantly (p0.05) different among locations and did not significantly vary between the plants treated with IMP and the existing management systems . T ropical Agricultural Research Vol. 25 (3): 376-395 (2014)

Vaccines for Prevention of Bluetongue and Epizootic Hemorrhagic Disease in Livestock: A North American Perspective.

Bluetongue (BT) and epizootic hemorrhagic disease (EHD) are noncontagious, insect-transmitted diseases of domestic and wild ruminants caused by related but distinct viruses. There are significant gaps in our scientific knowledge and available countermeasures to control an outbreak of orbivirus-induced disease, whether BT or EHD. Both BT virus (BTV) and EHD virus (EHDV) cause hemorrhagic fevers in susceptible ruminants; however, BT is principally a disease of domestic livestock whereas EHD is principally a disease of certain species of wild, non-African ungulates, notably white-tailed deer. The live-attenuated (modified live virus [MLV]) vaccines available in the United States for use in small ruminant livestock do provide good protection against clinical disease following infection with the homologous virus serotype. Although there is increasing justification that the use of MLV vaccines should be avoided if possible, these are the only vaccines currently available in the United States. Specifically, MLVs are used in California to protect sheep against infection with BTV serotypes 10, 11, and 17, and a MLV to BTV serotype 10 is licensed for use in sheep throughout the United States. These MLV vaccines may need to continue to be used in the immediate future for protective immunization of sheep and goats against BT. There are currently no licensed vaccines available for EHD in the United States other than autogenous vaccines. If there is a need to rapidly develop a vaccine to meet an emerging crisis associated with either BTV or EHDV infections, development of an inactivated virus vaccine in a conventional adjuvanted formulation will likely be required. With two doses of vaccine (and in some instances just one dose), inactivated vaccines can provide substantial immunity to the epizootic serotype of either BTV or EHDV. This strategy is similar to that used in the 2006-2008 BTV serotype 8 outbreaks in northern Europe that provided vaccine to the field within 2 years of the initial incursion (by 2008). Further research and development are warranted to provide more efficacious and effective vaccines for control of BTV and EHDV infections.

Cell-free expression, purification, and ligand-binding analysis of Drosophila melanogaster olfactory receptors DmOR67a, DmOR85b and DmORCO.

Insects transmit numerous devastating diseases, including malaria, dengue fever, and sleeping sickness. Olfactory cues guide insects to their hosts, and are thus responsible for disease transmission. Understanding the molecular basis of insect olfaction could facilitate the development of interventions. The first step is to heterologously overexpress and purify insect olfactory receptors (ORs). This is challenging, as ORs are membrane proteins. Here, we show that insect ORs and their co-receptor can be expressed in an E. coli cell-free system. After immunoaffinity chromatography, the ORs are ~95% pure, and up to 1 mg/10 ml reaction is obtained. Circular dichroism together with microscale thermophoresis indicate that each receptor is properly folded, and can bind its respective ligand. This is the first time insect ORs have been expressed in an E. coli system. The methods described here could facilitate future structure-function studies, which may aid in developments to alleviate the suffering of millions caused by insect-transmitted diseases.