VectorInfo: A web resource for medically important Indian arthropod disease vectors.

VectorInfo is a freely accessible web resource, emphasised on medically important Indian arthropods funded by Indian Council of Medical Research (ICMR) and maintained by one of its premier institute, Vector Control Research Centre (VCRC). VectorInfo elucidates and curates medically important Indian arthropod's biological, omics technologies to adopt a holistic view of the molecules that make up an organism, aimed at the detection of genomics, transcriptomics, proteomics, enzymes & pathways and immune specific genes. The nitty-gritty of VectorInfo is aimed at scrutinizing all the possible information on Indian disease vectors in a single window for the scientific community. The database affords 53 medically important Indian arthropod's biological and omics information well-structured and provided with downloadable facilities. In addition to this, huge number of research articles were mined in the quest for gathering the recommended insecticide targets and their mechanisms, that pave ways to design and develop novel lead molecules through computational means. This current up-to-date database contains 2,498 omics entries beneficial for the molecular studies and analysis. In order to maintain regular updates, user forms were provided for the scientific community to submit research data to the database administrator. The VectorInfo furthermore conveys various resources for vector control and diagnostics and the links to the crucial software tools used for the Bioinformatics analysis.

A high-throughput sequencing assay to comprehensively detect and characterize unicellular eukaryotes and helminths from biological and environmental samples.

BACKGROUND: Several of the most devastating human diseases are caused by eukaryotic parasites transmitted by arthropod vectors or through food and water contamination. These pathogens only represent a fraction of all unicellular eukaryotes and helminths that are present in the environment and many uncharacterized organisms might have subtle but pervasive effects on health, including by modifying the microbiome where they reside. Unfortunately, while we have modern molecular tools to characterize bacterial and, to a lesser extent, fungal communities, we lack suitable methods to comprehensively investigate and characterize most unicellular eukaryotes and helminths: the detection of these organisms often relies on microscopy that cannot differentiate related organisms, while molecular assays can only detect the pathogens specifically tested. RESULTS: Here, we describe a novel sequencing-based assay, akin to bacterial 16S rRNA sequencing, that enables high-throughput detection and characterization of a wide range of unicellular eukaryotes and helminths, including those from taxonomical groups containing all common human parasites. We designed and evaluated taxon-specific PCR primer pairs that selectively amplify all species from eight taxonomical groups (Apicomplexa, Amoeba, Diplomonadida, Kinetoplastida, Parabasalia, Nematoda, Platyhelminthes, and Microsporidia). We then used these primers to screen DNA extracted from clinical, biological, and environmental samples, and after next-generation sequencing, identified both known and previously undescribed organisms from most taxa targeted. CONCLUSIONS: This novel high-throughput assay enables comprehensive detection and identification of eukaryotic parasites and related organisms, from a wide range of complex biological and environmental samples. This approach can be easily deployed to many settings and will efficiently complement existing methods and provide a holistic perspective on the microbiome.

Amblyomma maculatum SECIS binding protein 2 and putative selenoprotein P are indispensable for pathogen replication and tick fecundity.

Selenium, a vital trace element, is incorporated into selenoproteins to produce selenocysteine. Our previous studies have revealed an adaptive co-evolutionary process that has enabled the spotted fever-causing tick-borne pathogen Rickettsia parkeri to survive by manipulating an antioxidant defense system associated with selenium, which includes a full set of selenoproteins and other antioxidants in ticks. Here, we conducted a systemic investigation of SECIS binding protein 2 (SBP2) and putative selenoprotein P (SELENOP) by transcript silencing in adult female Gulf-coast ticks (Amblyomma maculatum). Knockdown of the SBP2 and SELENOP genes depleted the respective transcript levels of these tick selenogenes, and caused differential regulation of other antioxidants. Importantly, the selenium level in the immature and mature tick stages increased significantly after a blood meal, but the selenium level decreased in ticks after the SBP2 and SELENOP knockdowns. Moreover, the SBP2 knockdown significantly impaired both transovarial transmission of R. parkeri to tick eggs and egg hatching. Overall, our data offer new insight into the relationship between the SBP2 selenoprotein synthesis gene and the putative tick SELENOP gene. It also augments our understanding of selenoprotein synthesis, selenium maintenance and utilization, and bacterial colonization of a tick vector.

Grandeur Alliances: Symbiont Metabolic Integration and Obligate Arthropod Hematophagy.

Several arthropod taxa live exclusively on vertebrate blood. This food source lacks essential metabolites required for the maintenance of metabolic homeostasis, and as such, these arthropods have formed symbioses with nutrient-supplementing microbes that facilitate their host's 'hematophagous' feeding ecology. Herein we highlight metabolic contributions of bacterial symbionts that reside within tsetse flies, bed bugs, lice, reduviid bugs, and ticks, with specific emphasis on B vitamin and cofactor biosynthesis. Importantly, these arthropods can transmit pathogens of medical and veterinary relevance and/or cause infestations that induce psychological and dermatological distress. Microbial metabolites, and the biochemical pathways that generate them, can serve as specific targets of novel control mechanisms aimed at disrupting the metabolism of hematophagous arthropods, thus combatting pest invasion and vector-borne pathogen transmission.

Chemical and Plant-Based Insect Repellents: Efficacy, Safety, and Toxicity.

Most emerging infectious diseases today are arthropod-borne and cannot be prevented by vaccinations. Because insect repellents offer important topical barriers of personal protection from arthropod-borne infectious diseases, the main objectives of this article were to describe the growing threats to public health from emerging arthropod-borne infectious diseases, to define the differences between insect repellents and insecticides, and to compare the efficacies and toxicities of chemical and plant-derived insect repellents. Internet search engines were queried with key words to identify scientific articles on the efficacy, safety, and toxicity of chemical and plant-derived topical insect repellants and insecticides to meet these objectives. Data sources reviewed included case reports; case series; observational, longitudinal, and surveillance studies; and entomological and toxicological studies. Descriptive analysis of the data sources identified the most effective application of insect repellents as a combination of topical chemical repellents, either N-diethyl-3-methylbenzamide (formerly N, N-diethyl-m-toluamide, or DEET) or picaridin, and permethrin-impregnated or other pyrethroid-impregnated clothing over topically treated skin. The insecticide-treated clothing would provide contact-level insecticidal effects and provide better, longer lasting protection against malaria-transmitting mosquitoes and ticks than topical DEET or picaridin alone. In special cases, where environmental exposures to disease-transmitting ticks, biting midges, sandflies, or blackflies are anticipated, topical insect repellents containing IR3535, picaridin, or oil of lemon eucalyptus (p-menthane-3, 8-diol or PMD) would offer better topical protection than topical DEET alone.

Mechanical transfer of Theileria orientalis: possible roles of biting arthropods, colostrum and husbandry practices in disease transmission.

BACKGROUND: The intracellular protozoal parasite Theileria orientalis has rapidly spread across South-eastern Australia, substantially impacting local cattle industries since 2006. Haemaphysalis longicornis appears to be a biological vector in the endemic regions. Mechanical transfer of blood by biting arthropods, in colostrum or iatrogenic transmission though husbandry procedures is another possible mode of transmission. This study assesses the risk of these mechanical modes of transmission. METHODS: Blood was collected from a T. orientalis Ikeda positive Angus steer, and was inoculated into the jugular vein of 9 calves in 3 treatment groups, each with 3 animals. Calves in Group 1 received 10 ml of cryopreserved blood, while those in Groups 2 and 3 received 1 ml (fresh blood) and 0.1 ml (cryopreserved), respectively. An additional three animals remained as negative controls and the donor calf was also followed as a positive control. Blood was collected over 3 months, and analysed via qPCR for the presence of the parasite. Samples of the sucking louse Linognathus vituli were collected opportunistically from calves 5 months after inoculation and tested for T. orientalis. For the colostral transmission study, 30 samples of blood and colostrum were collected from cows at calving in an endemic herd. These samples along with blood from their calves were tested by qPCR for T. orientalis and for antibodies to the major piroplasm surface protein (MPSP). RESULTS: Eight of the nine inoculated calves became positive for T. orientalis. The prepatent period of these infections was inversely correlated with inoculation dose. All negative control calves remained negative and the positive control calf remained positive. Samples of L. vituli tested positive for T. orientalis Ikeda, while some samples of colostrum were also shown to be qPCR and anti-MPSP positive. All calves in the colostral study tested qPCR negative although one was antibody-positive. CONCLUSIONS: T. orientalis is capable of being mechanically transferred by intravenous inoculation with small volumes of blood and is detectable up to 5 months post-infection. Animals infected by this means may play a significant role in the transmission of the disease by acting as asymptomatic carriers. Other modes of blood transfer, including biting arthropods and colostral transfer are also possible modes of disease transmission.

Tick repellents for human use: prevention of tick bites and tick-borne diseases.

Ticks are arthropods and the most important vectors of major human diseases after mosquitoes. Due to their impact on public health, in vitro and in vivo assays have been developed to identify molecules with repellent activities on ticks. Repellents are useful to reduce tick bite exposure and the potential transmission of pathogens; they can be used topically or in impregnated clothing. Presently, mainly synthetic molecules are commercialized as skin repellents, e.g., N,N-diethyl-meta-toluamide (DEET), IR3535, picaridin or KBR 3023, and para-menthanediol. Permethrin is largely used for fabric impregnation. Intensive research has been conducted to identify new molecules with repellent activity and more recently, plant-derived molecules, as an alternative to synthetic molecules.

Repellency of cassia bark, eucalyptus, and star anise oils and their major constituents to Leptotrombidium pallidum (Acari: Trombiculidae).

Leptotrombidium pallidum (Nagoya, Miyagawa, Mitamura & Tamiya) is a primary vector of Orientia tsutsugamushi (Hyashi), the causative agent of scrub typhus. An assessment is made of the repellency to L. pallidum larvae (chiggers) of cassia bark, eucalyptus, and star anise oils and major constituents (E)-cinnamaldehyde, 1,8-cineole, and (E)-anethole of the corresponding oils. Results were compared with those of conventional repellents DEET (N,N-diethyl-3-methylbenzamide), IR3535 [(ethyl 3-[acetyl(butyl)amino]propanoate)], and permethrin. Based on the median repellent concentration (RC50) values, (E)-cinnamaldehyde, (E)-anethole, cassia bark oil, and star anise oil (RC50, 0.95-1.52 mg/cm2) exhibited significantly more potent repellency than DEET (3.85 mg/cm2). (E)-cinnamaldehyde, (E)-anethole, cassiabark oil, 1,8-cineole, and star anise oil were approximately 43, 16, 11, 8, and 4 times more effective than IR3535 (CC5, 6.51%) as judged by the median climbing distance-disturbing concentration (CC50) values. The median residual duration time of repellency (RT50) was significantly more pronounced in DEET (RT50, 323 min) than in all essential oils and constituents (108-167 min). In the light of global efforts to reduce the level of highly toxic synthetic repellents, the three essential oils and their major constituents described merit further study as potential biorepellents for the control of L. pallidum populations.

Prevention of vector transmitted diseases with clove oil insect repellent.

Vector repellent is one element in the prevention of vector-borne diseases. Families that neglect protecting their children against vectors risk their children contracting illnesses such as West Nile virus, eastern equine encephalitis, Lyme disease, malaria, dengue hemorrhagic fever, yellow fever, babesiosis, Crimean-Congo hemorrhagic fever, Rocky Mountain spotted fever, Southern tick-associated rash illness, ehrlichiosis, tick-borne relapsing fever, tularemia, and other insect and arthropod related diseases (CDC, 2011). Identification of families at risk includes screening of the underlying basis for reluctance to apply insect repellent. Nurses and physicians can participate in a positive role by assisting families to determine the proper prophylaxis by recommending insect repellent choices that are economical, safe, and easy to use. A holistic alternative might include the suggestion of clove oil in cases where families might have trepidations regarding the use of DEET on children. This article will explore the safety and effectiveness of clove oil and its use as an insect repellent.

Larvicidal efficacy of botanical extracts against two important vector mosquitoes.

OBJECTIVE: To determine the larvicidal efficacy of different solvent leaf extract of Ervatamia coronaria and Caesalpinia pulcherrima against Anopheles subpictus and Culex tritaeniorhynchus. MATERIALS AND METHODS: Twenty five early third instar larvae of Anopheles subpictus and Culex tritaeniorhynchus were exposed to various concentrations and were assayed in the laboratory. The larval mortality was observed after 24 h of treatment. RESULTS: Among three solvent extracts tested the maximum efficacy was observed in the methanol extract. The LC50 (LC90) values of Ervatamia coronaria and Caesalpinia pulcherrima against early third instar of Anopheles subpictus were 86.47 (159.59) and 113.26 (207.73) ppm and Culex tritaeniorhynchus were 131.53 (245.37) and 165.28 (299.45) ppm, respectively. No mortality was observed in controls. CONCLUSIONS: From the results it can be concluded the crude extract of Ervatamia coronaria and Caesalpinia pulcherrima were excellent potential for controlling Anopheles subpictus and Culex tritaeniorhynchus mosquito larvae.

Plant extracts, isolated phytochemicals, and plant-derived agents which are lethal to arthropod vectors of human tropical diseases--a review.

The recent scientific literature on plant-derived agents with potential or effective use in the control of the arthropod vectors of human tropical diseases is reviewed. Arthropod-borne tropical diseases include: amebiasis, Chagas disease (American trypanosomiasis), cholera, cryptosporidiosis, dengue (hemorrhagic fever), epidemic typhus (Brill-Zinsser disease), filariasis (elephantiasis), giardia (giardiasis), human African trypanosomiasis (sleeping sickness), isosporiasis, leishmaniasis, Lyme disease (lyme borreliosis), malaria, onchocerciasis, plague, recurrent fever, sarcocystosis, scabies (mites as causal agents), spotted fever, toxoplasmosis, West Nile fever, and yellow fever. Thus, coverage was given to work describing plant-derived extracts, essential oils (EOs), and isolated chemicals with toxic or noxious effects on filth bugs (mechanical vectors), such as common houseflies (Musca domestica Linnaeus), American and German cockroaches (Periplaneta americana Linnaeus, Blatella germanica Linnaeus), and oriental latrine/blowflies (Chrysomya megacephala Fabricius) as well as biting, blood-sucking arthropods such as blackflies (Simulium Latreille spp.), fleas (Xenopsylla cheopis Rothschild), kissing bugs (Rhodnius Stål spp., Triatoma infestans Klug), body and head lice (Pediculus humanus humanus Linnaeus, P. humanus capitis De Geer), mosquitoes (Aedes Meigen, Anopheles Meigen, Culex L., and Ochlerotatus Lynch Arribálzaga spp.), sandflies (Lutzomyia longipalpis Lutz & Neiva, Phlebotomus Loew spp.), scabies mites (Sarcoptes scabiei De Geer, S. scabiei var hominis, S. scabiei var canis, S. scabiei var suis), and ticks (Ixodes Latreille, Amblyomma Koch, Dermacentor Koch, and Rhipicephalus Koch spp.). Examples of plant extracts, EOs, and isolated chemicals exhibiting noxious or toxic activity comparable or superior to the synthetic control agents of choice (pyrethroids, organophosphorous compounds, etc.) are provided in the text for many arthropod vectors of tropical diseases.

Use of plant-derived products to control arthropods of veterinary importance: a review.

The use of synthetic products in veterinary pest management is becoming increasingly problematic. Issues, including pest resistance, product withdrawal, undesirable environmental persistence, and high mammalian toxicity associated with synthetic pesticides, are driving research to identify new pest management approaches. One approach employs the repellent/toxic effects of plant-derived products (PDPs). Several pesticides based on PDPs are already available in some areas of pest management. This review highlights instances in which such products have been used with success against pests of domestic animals, livestock, apiculture, and poultry.

Presidential address. Flavor buds and other delights.

Using good sense and some biological information, one can enjoy a delightful morsel or enhanced meal from a variety of parasites, either raw or cooked. Bon Appétit!

Coffee ringspot virus vectored by Brevipalpus phoenicis (Acari: Tenuipalpidae) in coffee.

Coffee ringspot is characterized by conspicuous ringspot symptoms on leaves, berries, and less frequently on twigs. It is caused by coffee ringspot virus (CoRSV), a short, bacilliform virus (40 nm x 100-110 nm). The virus is not seed borne and is transmitted by Brevipalpus phoenicis (Geijskes). Transovarial transmission within the mite does not occur. CoRSV has been mechanically transmitted to Chenopodium amaranticolor Coste and Reynaud, C. quinoa Wildenow, Beta vulgaris L., and Alternanthera tenella Colla resulting in local lesions. Systemic infection within both C. amaranticolor and C. quinoa occurs. Virions are found in the nucleus or cytoplasm of infected cells, commonly associated with membranes. Occasionally, membrane bounded particles are found within the cisternae of the endoplasmic reticulum. A characteristic electron lucent, nuclear inclusion is commonly found in many infected cells. These cytopathic effects place CoRSV among the nuclear type of Brevipalpus-borne viruses. The disease has been reported in several Brazilian states (São Paulo, Paraná, Minas Gerais, and Federal District) and recently found in Costa Rica. A similar disease is known in the Philippines, but no information exists about its relationship to CoRSV. Coffee ringspot had no economical significance until recently when a large scale infection was reported in Minas Gerais that resulted in yield loss.

Malaria control: achievements, problems and strategies.

Even if history has not always been the Magistra vitae, Cicero expected it to be, it should provide, as Baas said, a mirror in which to observe and compare the past and present in order to draw therefrom well-grounded conclusions for the future. Based on this belief, this paper aims to provide an overview of the foundations and development of malaria control policies during the XX century. It presents an analysis of the conflicting tendencies which shaped the development of these policies and which appear to have oscillated between calls for frontal attack in an all-out campaign and calls for sustainable gains, even if slow. It discusses the various approaches to the control of malaria, their achievements and their limitations, not only to serve as a background to understand better the foundations of current policies, but also to prevent that simplistic generalisations may again lead to exaggerated expectations and disillusion. The first part of the paper is devoted to the development of malaria control during the first half of the century, characterised by the ups and downs in the reliance on mosquito control as the control measure applicable everywhere. The proliferation of "man-made-malaria", which accompanied the push for economic development in most of the endemic countries, spurred the need for control interventions and, while great successes were obtained in many specific projects, the general campaigns proposed by the enthusiasts of vector control faced increasing difficulties in their practical implementation in the field. Important events, which may be considered representative of this period are, on the campaign approach, the success of Gorgas in the Panama Canal, but also the failure of the Mian Mir project in India; while on the developmental approach, the Italian and Dutch schools of malariology, the Tennessee Valley and the development of malaria sanitation, included the so called species sanitation. The projection of these developments to a global scale was steered by the Malaria Commission of the League of Nations and greatly supported by the Rockefeller Foundation. Perhaps the most important contribution of this period was the development of malaria epidemiology, including the study of the genesis of epidemics and their possible forecasting and prevention. Although the great effectiveness of DDT was perhaps the main determinant for proposing the global eradication of the disease in the 1950s, it was the confidence in the epidemiological knowledge and the prestige of malariology, which gave credibility to the proposal at the political level. The second part deals with the global malaria eradication campaign of the 1950s and 1960s. It recognises the enormous impact of the eradication effort in the consolidation of the control successes of the first half of the century, as well as its influence in the development of planning of health programmes. Nevertheless, it also stresses the negative influence that the failure to achieve its utopian expectations had on the general disappointment and slow progress of malaria control, which characterised the last third of the century. The paper then analyses the evolution of malaria control funding, which often appears out of tune with political statements. The fourth part is devoted to the search for realistic approaches to malaria control, leading to the adoption of the global malaria control strategy in Amsterdam in 1992, and the challenge, at the end of the century, to rally forces commensurate with the magnitude of the problem, while aiming at realistic objectives. After discussing the conflicting views on the relations between malaria and socio-economic development and the desirable integration of malaria control into sustainable development, the paper ends with some considerations on the perspectives of malaria control, as seen by the author in early 1998, just before the launching of the current Roll Back Malaria initiative by WHO.

Epidemiology and control of malaria and other arthropod-borne diseases.

Malaria and other arthropod born diseases remain a serious public health problem affecting the lives and health of certain social groups when the two basic strategies to control fail due to: (1) the lack of effective chemoprophylaxis/chemotherapy or the rapid development of drug resistance of the infectious agents and (2) the ineffectiveness of pesticides or the arthropod vectors develop resistance to them. These situations enhances the need for the design and implementation of other alternatives for sustainable health programmes. The application of the epidemiological methods is essential not only for analyzing the relevant data for the understanding of the biological characteristics of the infectious agents, their reservoirs and vectors and the methods for their control, but also for the assessment of the human behaviour, the environmental, social and economic factors involved in disease transmission and the capacity of the health systems to implement interventions for both changes in human behaviour and environmental management to purpose guaranteed prevention and control of malaria and other arthropod born diseases with efficiency, efficacy and equity. This paper discuss the evolution of the malaria and arthropod diseases programmes in the American Region and the perspectives for their integration into health promotion programs and emphasis is made in the need to establish solid basis in the decision-making process for the selection of intervention strategies to remove the risk factors determining the probability to get sick or die from ABDs. The implications of the general planning and the polices to be adopted in an area should be analyzed in the light of programme feasibility at the local level, in the multisectoral context of specific social groups and taking in consideration the principles of stratification and equity.

Combate aos vetores da febre amarela e do dengue Aedes aegypti/Aedes albopictus: instruçöes para guardas, guardas-chefes e inspetores / Combat against vectors of yelow fever and dengue Aedes aegypti/Aedes Albopictus: instructions for guards, guard-chiefs and inspectors

O manual destina-se aos guardas, guardas-chefes e inspetores da SUCAM que trabalham no Programa de Controle da Febre Amarela e no combate ao Aedes Aegypti e Albopictus. Contém regulamento disciplinar e noçöes gerais sobre a doença e seu controle. (AMSB)