Active clinical trials for "Arbovirus Infections"

Arboviruses, diseases transmitted to humans by the bite of an insect vector, are a major public health problem, particularly in tropical and sub-tropical countries. In New Caledonia, dengue epidemics are recurrent and may be associated with the co-circulation of other arboviruses such as Zika or chikungunya. The virological determinants which condition the occurrence of these epidemics may be linked to an increased vectorial competence of the vector mosquito Aedes aegypti for a particular viral isolate. In fact, the Aedes aegypti mosquito is infected by making a blood meal on a person infected with an arbovirus. The virus infects its digestive tract, then spreads throughout the mosquito's body until it reaches its salivary glands. The virus is then present in the saliva and will be injected into the human host during a new blood meal. Some viral variants are best transmitted by Aedes aegypti. In general, the study of this vectorial competence is carried out by experiments in the laboratory during which an artificial blood meal composed of mammalian blood (human, rabbit, etc.) is mixed with a viral stock. Carrying out deported blood meals during which blood collected from patients infected with an arbovirus is used to gorge mosquitoes makes it possible to place oneself in experimental conditions as close as possible to the natural cycle of transmission of arboviruses. In the human host, cells of the myeloid lineage present in the peripheral blood constitute preferred targets of replication for arboviruses. At the same time, the peripheral blood cells of patients are activated in response to infection and secrete many soluble factors released into the blood of patients. The study of blood samples from patients infected with arboviruses is therefore of prime importance for understanding both the replicative mechanisms of arboviruses but also the immune response they induce.

The primary objective of the study is to demonstrate and quantify the protective efficacy (PE) of a single SR product, in reducing DENV infection and active Aedes-borne virus (ABV) disease in human cohorts. The study design will be a prospective, cluster randomized controlled trial (cRCT). Although not a specific objective of this project, an overall goal is to allow for official recommendations (or not) from the World Health Organization (WHO) for the use of SRs in public health. A WHO global policy recommendation will establish evaluation systems of SR products to regulate efficacy evaluations, thereby increasing quality, overall use and a consequent reduction in disease.

Arboviruses, diseases transmitted to humans by the bite of an insect vector, are a major public health problem, especially in tropical and sub-tropical countries. A promising strategy aimed at blocking the circulation of arboviruses is to release Aedes aegypti mosquitoes carrying the endosymbiotic bacterium Wolbachia. In 2019, the Wolbachia strategy was implemented in Nouméa as part of the World Mosquito Program. This intervention will modify the epidemiological profile of arboviruses in New Caledonia. Epidemiological surveillance of arboviruses requires molecular characterization of the virus contained in the serum obtained from the blood collected from patients. This molecular characterization by RNA isolation techniques, RT-qPCR monitoring and sequencing allows the construction of phylogenetic trees. In the context of the implementation of the World Mosquito Program in Nouméa, the investigators plan to follow the molecular evolution of arboviruses, over the period preceding the releases of mosquitoes carrying Wolbachia (from 1995 to 2019) then over a period of 5 years. following the releases. At the same time, the virus can be isolated by cell culture techniques and in vitro infections, allowing its study in vitro in cells or in vivo in mosquitoes. This study allows us to measure the impact of the Wolbachia strategy on the evolution of the virus's ability to replicate in cells in the presence of Wolbachia and to be transmitted by the mosquito.

A local network is being set up to study the impact of arboviruses in our region. It is committed to a one-health approach, in particular with research without a priori for new viruses hosted among vectors and wildlife. The candidates identified by high throughput sequencing approaches will serve as a basis for the development of serological and molecular tools for their detections. These tools will be used to assess the possible circulation of these new viruses in humans in biological collections created within the framework of this project Arbodocc .

The dengue, Zika and chikungunya arboviruses represent potentially severe infections to which the New Caledonian population is exposed. In the absence of specific treatment or vaccine, vector control remains the method of choice to limit their spread. However, the traditional methods of prevention and vector control measure today face their limits: mosquito resistance to insecticides, difficulty of access and destruction of breeding areas... The World Mosquito Program Noumea project is based on the artificial colonization of the mosquito vector Aedes aegypti by the endosymbiotic bacteria Wolbachia, which reduces its ability to transmit arboviruses. The breeding of mosquitoes carrying the bacterium Wolbachia in the laboratories of the Institut Pasteur of New Caledonia requires the use of human blood samples for mosquito gorging. The objective of the research is to generate, maintain and amplify Aedes aegypti Caledonian lineages carrying the Wolbachia bacteria for the planned insect release program in Noumea.

Isolated minority communities in China use traditional plant-based methods of mosquito control. This study is evaluating 4 plants used in this way by monitoring mosquitoes entering houses on nights when the plants are being used in this way. A blind, placebo controlled study design will monitor plant use and record mosquito species / numbers caught in CDC light traps indoors over 3 months.

Dengue viruses are the most medically important arthropod-borne pathogens worldwide, with transmission occurring in most tropical and sub-tropical regions. An estimated 390 million infections occur yearly. Although, there are considerable ongoing efforts to develop a vaccine, vector control remains the only option for reducing dengue virus (DENV) transmission and disease burden. The recent emergence of Aedes-borne Zika (ZIKV) and Chikungunya viruses (CHIKV) highlight need for novel vector control tools. The goal of this project is to determine the efficacy of a spatial repellent (SR) product (active ingredient transfluthrin) for reducing contact between household residents and vector mosquitos and as a result reduce DENV, ZIKV, and/or other Aedes-borne virus transmission. Henceforth the investigators will designate the combined risk of Aedes-borne dengue, Chikungunya, Zika virus transmission by (DCZV). Spatial repellency is used here as a general term to refer to a range of insect behaviors caused by airborne chemicals that reduce contact between people and disease vectors. This can include movement away from a chemical stimulus, and interference with host detection (attraction-inhibition) and/or feeding response.

This is a multi-center case-control study that aims to define the association between the exposure to an arbovirus infection and the development of a neurological syndrome in patients from Colombia. The study makes part of the Neurovirus Emerging in the Americas Study (NEAS) that is a collaborative effort that looks to combine the efforts of researchers, healthcare providers and patients in Colombia to establish a comprehensive registry of the clinical, radiological and laboratory profile of patients with new onset of neurological diseases associated mosquito-borne viruses, known as arboviruses.

Dengue is an important public health problem despite the efforts of local health authorities to mitigate the impact of epidemics and the epidemiology of dengue evolved from an endemo-epidemic to a hyper-endemic state. In late 2013, the first local transmission of chikungunya virus in the Americas was identified in Caribbean countries and territories including French Guiana. Rapidly, more than 16,000 suspected local Health authorities had reported cases. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil. The emergence of Zika virus in South America led to a rapid spread throughout South and Central America, reaching French Guiana in December 2015. With the increasing frequency of epidemics related to arbovirus and the resulting health, social, and economic impacts of dengue, the surveillance of arbovirus have become social, political, and public health challenges that require specific and non-available immune status information.

Background: Zika virus is mostly passed on by the bite of an infected mosquito. It usually causes mild illness. But in pregnant women it can cause serious birth defects to the baby. The virus can also spread by blood transfusion and sexual intercourse. This is why the U.S. Food & Drug Administration (FDA) recommended that people should not give blood if possibly exposed to Zika virus. Dengue virus and chikungunya virus are passed by the same mosquitoes as Zika virus. These can cause severe reactions if passed through transfused blood. Donated blood is usually not tested for these three viruses. Researchers want to count the infections in people who have been exposed because of travel or sexual exposure. They want to learn the risk these viruses might pose to the U.S. blood supply. They also want to study the natural history of these viruses by following infected people over time. Objective: To study the risk of Zika, dengue, and chikungunya viruses to the U.S. blood supply. Eligibility: Adults age 18 or older who were turned down for donating blood because of possible exposure to certain viruses. Design: Participants will have blood and urine tests. They will answer questions about their travel. They will be called in about a week with virus test results. Participants with negative results do not have any more study visits. Participants with positive results will be asked to stay in the study for 6 months. They will have weekly clinic visits and tests until results are negative for 2 straight weeks. Once test results are negative, they will have monthly visits. Visits will include physical exams, blood and urine samples, and optional semen samples from men. Most people will have 3-4 weekly visits and 5 monthly visits.