In Grenada, West Indies, What Is the Degree of Bat-human Interaction in Households and Is It Associated to Arboviral Disease?

Background: Bats are reservoirs for several zoonotic pathogens, making human-bat interactions particularly concerning. Recent studies documented that Grenadian bats can be infected with Zika, dengue and Chikungunya viruses and Leptospira bacteria among other pathogens. The objective of this study was to estimate the number of homes in Grenada that have a bat infestation, and to determine whether there is a correlation between the number of bat infested homes with the type of roofing or the presence of arbovirus infections of human inhabitants. Methods: An institutional review board (IRB) approved questionnaire delivered through a semi-structured interview was administered at the central bus stop in St. George, Grenada to recruit participants from all six parishes and the island of Carriacou. Results determined the percentage of individuals that had bat roosts in their households, whether this was of concern to them, whether they had taken any steps to keep bats out of their residence, and whether they had confirmed or suspected cases of dengue, Zika or Chikungunya virus infections. Information on the type of roofing and presence of window screens were also documented. Bat type (fruit vs insect eating bats) was attempted by guano description. Results: Results from 210 individual responses provided data showing all six parishes were represented although not equally. Having bats at the household was not associated with parish of residence, roof type or presence or absence of window screens. The results showed 60% of homes in Grenada are bat-infested and 51% of people self-reported recent arbovirus infection; but no correlation between the two. Also, no correlation to a specific type of roof or type of bat was found.Conclusions: A statistically significant number of inhabitants had attempted to remove bats from their homes, indicating that bats are perceived as pest to homes in Grenada, and justifying further research into relocating bats through the use of construction changes, awareness, and the creation of bat houses.

Challenges, Advances and Opportunities in Exploring Natural Products to Control Arboviral Disease Vectors

Natural products constitute an important source of molecules for product development. However, despite numerous reports of compounds and active extracts from biodiversity, poor and developing countries continue to suffer with endemic diseases caused by arboviral vectors, including dengue, Zika, chikungunya and urban yellow fever. Vector control remains the most efficient disease prevention strategy. Wide and prolonged use of insecticides has resulted in vector resistance, making the search for new chemical prototypes imperative. Considering the potential of natural products chemistry for developing natural products-based products, including insecticides, this contribution discusses the general aspects and specific characteristics involved in the development of drug leads for vector control. Throughout this work, we highlight the obstacles that need to be overcome in order for natural products compounds to be considered promising prototypes. Moreover, we analyze the bottlenecks that should be addressed, together with potential strategies, to rationalize and improve the efficiency of the drug discovery process.

Modeling unmanned aerial vehicle system for identifying foci of arboviral disease with monitoring system

People who live in low-income and hard-to-reach regions are usually the most affected ones by high incidences of arboviral diseases, increasing morbidity and mortality rates, and public health costs. We present the modeling of hardware and software components of an unmanned aerial vehicle (UAV) system by mathematical tools, focusing on monitoring foci of arboviral diseases transmitted by Aedes aegypti mosquito, e.g., Zika, Chikungunya, and Dengue. We used restriction equations and the colored Petri nets formal modeling language to represent the flight dynamics and the software components of the system, respectively. We evaluated the specification of desired behaviors of the monitoring system using simulations and the model checking technique. The results showed the completeness and correctness of the specification. The design of such a system is challenging due to the potential risks to people and the environment. Therefore, this study provides insights into the development of an UAV system for such an application scenario. The monitoring system has the potential of improving the efficiency in identifying foci of arboviral diseases.

Genetic Diversity of Dengue Virus in Clinical Specimens from Bangkok, Thailand, during 2018–2020: Co-Circulation of All Four Serotypes with Multiple Genotypes and/or Clades

Dengue is an arboviral disease highly endemic in Bangkok, Thailand. To characterize the current genetic diversity of dengue virus (DENV), we recruited patients with suspected DENV infection at the Hospital for Tropical Diseases, Bangkok, during 2018–2020. We determined complete nucleotide sequences of the DENV envelope region for 111 of 276 participant serum samples. All four DENV serotypes were detected, with the highest proportion being DENV-1. Although all DENV-1 sequences were genotype I, our DENV-1 sequences were divided into four distinct clades with different distributions in Asian countries. Two genotypes of DENV-2 were identified, Asian I and Cosmopolitan, which were further divided into two and three distinct clades, respectively. In DENV-3, in addition to the previously dominant genotype III, a cluster of 6 genotype I viruses only rarely reported in Thailand was also observed. All of the DENV-4 viruses belonged to genotype I, but they were separated into three distinct clades. These results indicated that all four serotypes of DENV with multiple genotypes and/or clades co-circulate in Bangkok. Continuous investigation of DENV is warranted to further determine the relationship between DENV within Thailand and neighboring countries in Southeast Asia and Asia.

Dragonflies as an Important Aquatic Predator Insect and Their Potential for Control of Vectors of Different Diseases

Mosquitoes belong to order of Diptera. The main important vectors are genus Aedes, Culex and Anopheles. They transmit different agents such bacteria, viruses, and parasites. According to the latest information around 7 hundred million people around the world are suffering from mosquitoborne illness resulting over one million deaths. The main important disease transmitted by Anopheles is malaria. Other genus of mosquitoes including Aedes and Culex species transmit different arboviral disease to human. According to guideline of World Health Organization, the mina control of disease is vectors control. The main important vector control is using different insecticides. Using chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. In this research all, the relevant information regarding the topic of research is research through the internet and used in this paper. An intensive search of scientific literature was done in “PubMed”, “Web of Knowledge”, “Scopus”, “Google Scholar”, “SID”, etc Results shows that one of important environmental friendly vector control is biological control, using different predators and other microorganisms for vector and pest control. Dragonflies do eat mosquitos and serve as mosquito predators. They feed on mosquitos and reduce their number in outdoor areas. The dragonflies are scary biters, but they are dangerous to mosquitos. Worldwide results showed that dragonflies are able to control Aedes, Culex and Anopheles mosquito species. The artificial rearing of these predators and releasing for biological control is an appropriate measure for vector control worldwide.

Improved detection of flaviviruses in Australian mosquito populations via replicative intermediates

Mosquito-borne flaviviruses are significant contributors to the arboviral disease burdens both in Australia and globally. While routine arbovirus surveillance remains a vital exercise to identify known flaviviruses in mosquito populations, novel or divergent and emerging species can be missed by these traditional methods. The MAVRIC (monoclonal antibodies to viral RNA intermediates in cells) system is an ELISA-based method for broad-spectrum isolation of positive-sense and double-stranded RNA (dsRNA) viruses based on detection of dsRNA in infected cells. While the MAVRIC ELISA has successfully been used to detect known and novel flaviviruses in Australian mosquitoes, we previously reported that dsRNA could not be detected in dengue virus-infected cells using this method. In this study we identified additional flaviviruses which evade detection of dsRNA by the MAVRIC ELISA. Utilising chimeric flaviviruses we demonstrated that this outcome may be dictated by the non-structural proteins and/or untranslated regions of the flaviviral genome. In addition, we report a modified fixation method that enables improved detection of flavivirus dsRNA and inactivation of non-enveloped viruses from mosquito populations using the MAVRIC system. This study demonstrates the utility of anti-dsRNA monoclonal antibodies for identifying viral replication in insect and vertebrate cell systems and highlights a unique characteristic of flavivirus replication.

Arboviral diseases and poverty in Alabama, 2007–2017

Mosquito-borne viruses cause diseases of great public health concern. Arboviral disease case distributions have complex relationships with socioeconomic and environmental factors. We combined information about socio-economic (population, and poverty rate) and environmental (precipitation, and land use) characteristics with reported human cases of arboviral disease in the counties of Alabama, USA, from 2007–2017. We used county level data on West Nile virus (WNV), dengue virus (DENV), chikungunya virus (CHIKV), Zika virus (ZIKV), California serogroup virus, Eastern equine encephalitis virus, and Saint Louis encephalitis virus to provide a detailed description of their spatio-temporal pattern. We found a significant spatial convergence between incidence of WNV and poverty rate clustered in the southern part of Alabama. DENV, CHIKV and ZIKV cases showed a different spatial pattern, being mostly located in the northern part, in areas of high socioeconomic status. The results of our study establish that poverty-driven inequities in arboviral risk exist in the southern USA, and should be taken into account when planning prevention and intervention strategies.

Entomovirological Surveillance in Schools: Are They a Source for Arboviral Diseases Transmission?

Surveillance and control activities for virus-transmitting mosquitoes have primarily focused on dwellings. There is little information about viral circulation in heavily trafficked places such as schools. We collected and analyzed data to assess the presence and prevalence of dengue, chikungunya, and Zika viruses in mosquitoes, and measured Aedes indices in schools in Medellín (Colombia) between 2016–2018. In 43.27% of 2632 visits we collected Aedes adults, creating 883 pools analyzed by RT-PCR. 14.27% of pools yielded positive for dengue or Zika (infection rates of 1.75–296.29 for Aedes aegypti). Ae. aegypti was more abundant and had a higher infection rate for all studied diseases. Aedes indices varied over time. There was no association between Aedes abundance and mosquito infection rates, but the latter did correlate with cases of arboviral disease and climate. Results suggest schools are important sources of arbovirus and health agencies should include these sites in surveillance programs; it is essential to know the source for arboviral diseases transmission and the identification of the most population groups exposed to these diseases to research and developing new strategies.

Technical viability of the YF MAC-HD ELISA kit for use in yellow fever-endemic regions

Yellow fever (YF), an arboviral disease, affects an estimated 200,000 people and causes 30,000 deaths per year and recently has caused major epidemics in Africa and South America. Timely and accurate diagnosis of YF is critical for managing outbreaks and implementing vaccination campaigns. A YF immunoglobulin M (IgM) antibody-capture (MAC) enzyme-linked immunosorbent assay (ELISA) kit, the YF MAC-HD, was successfully introduced starting in 2018 to laboratories in Africa and South America. The YF MAC-HD kit can be performed in 3.5 hours, test up to 24 samples, and includes all reagents necessary to perform the test, except for water used to dilute wash buffer. In 2018 and 2019, a total of 56 laboratory personnel from 39 countries in Africa and South America were trained to use the kit during workshops, followed by take-home YF IgM proficiency testing (PT) exercises. Participants received either a 10- or 20-sample YF PT panel and performed testing using the YF MAC-HD kit. All countries obtained 90% or higher correct results. These results verified the technical viability and transferability of YF MAC-HD kit use for laboratories in YF-endemic countries.