Rapid and real-time assays for detection and quantification of Chikungunya virus

An Overview of Indian Biomedical Research on the Chikungunya Virus with Particular Reference to Its Vaccine, an Unmet Medical Need

Chikungunya virus (CHIKV) is an infectious agent spread by mosquitos, that has engendered endemic or epidemic outbreaks of Chikungunya fever (CHIKF) in Africa, South-East Asia, America, and a few European countries. Like most tropical infections, CHIKV is frequently misdiagnosed, underreported, and underestimated; it primarily affects areas with limited resources, like developing nations. Due to its high transmission rate and lack of a preventive vaccine or effective treatments, this virus poses a serious threat to humanity. After a 32-year hiatus, CHIKV reemerged as the most significant epidemic ever reported, in India in 2006. Since then, CHIKV-related research was begun in India, and up to now, more than 800 peer-reviewed research papers have been published by Indian researchers and medical practitioners. This review gives an overview of the outbreak history and CHIKV-related research in India, to favor novel high-quality research works intending to promote effective treatment and preventive strategies, including vaccine development, against CHIKV infection.

Australia's notifiable disease status, 2016: Annual report of the National Notifiable Diseases Surveillance System

Abstract

In 2016, a total of 67 diseases and conditions were nationally notifiable in Australia. The states and territories reported 330,387 notifications of communicable diseases to the National Notifiable Diseases Surveillance System. Notifications have remained stable between 2015 and 2016. In 2016, the most frequently notified diseases were vaccine preventable diseases (139,687 notifications, 42% of total notifications); sexually transmissible infections (112,714 notifications, 34% of total notifications); and gastrointestinal diseases (49,885 notifications, 15% of total notifications). Additionally, there were 18,595 notifications of bloodborne diseases; 6,760 notifications of vectorborne diseases; 2,020 notifications of other bacterial infections; 725 notifications of zoonoses and one notification of a quarantinable disease.

Development of magnetic bead based sample extraction coupled polymerase spiral reaction for rapid on-site detection of Chikungunya virus

The molecular detection system has evolved over last two decades and is rapidly replacing the conventional confirmatory techniques in diagnostic virology. However the major limitation in implementation of available molecular detection assays is the non availability of field deployable nucleic acid isolation platform coupled with gene amplification technique. The rapid and early molecular detection is crucial for employing effective measure against many viral infections. The re-emergence of chikungunya virus (CHIKV) has led to epidemics since 2004 in several parts of the world including India. The main association of CHIKV with severe arthritis and long-lasting arthralgia and closely mimics symptoms of Dengue and Zika virus infection requiring laboratory confirmation. In this study, a simple magnetic bead based ribonucleic acid extraction method was optimized, which was coupled with isothermal polymerase spiral reaction (PSR) technique for early and rapid detection. Subsequently, the polymerase spiral reaction reagents were converted to dry down format that led to a rapid user friendly field compatible sample processing to answer method for rapid and onsite detection of Chikungunya virus. Both the methods were evaluated with a panel of clinical samples. The sensitivity of the assays were compared with available commercial viral RNA extraction platform and qRT-PCR. The in-house nucleic acid extraction system based on magnetic bead followed by dry down RT-Polymerase Spiral Reaction assay was found to be highly sensitive with 10 copies of RNA as limit of detection in CHIKV clinical specimens. With respect to other closely related viruses no cross reactivity was observed. This novel methodology has the potential to revolutionize the diagnosis of infectious agents in resource limited settings around the world.

Australia’s notifiable disease status, 2015: Annual report of the National Notifiable Diseases Surveillance System

In 2015, 67 diseases and conditions were nationally notifiable in Australia. States and territories reported a total of 320,480 notifications of communicable diseases to the National Notifiable Diseases Surveillance System, an increase of 16% on the number of notifications in 2014. In 2015, the most frequently notified diseases were vaccine preventable diseases (147,569 notifications, 46% of total notifications), sexually transmissible infections (95,468 notifications, 30% of total notifications), and gastrointestinal diseases (45,326 notifications, 14% of total notifications). There were 17,337 notifications of bloodborne diseases; 12,253 notifications of vectorborne diseases; 1,815 notifications of other bacterial infections; 710 notifications of zoonoses and 2 notifications of quarantinable diseases.

A scoping review of published literature on chikungunya virus

Chikungunya virus (CHIKV) has caused several major epidemics globally over the last two decades and is quickly expanding into new areas. Although this mosquito-borne disease is self-limiting and is not associated with high mortality, it can lead to severe, chronic and disabling arthritis, thereby posing a heavy burden to healthcare systems. The two main vectors for CHIKV are Aedes aegypti and Aedes albopictus (Asian tiger mosquito); however, many other mosquito species have been described as competent CHIKV vectors in scientific literature. With climate change, globalization and unfettered urban planning affecting many areas, CHIKV poses a significant public health risk to many countries. A scoping review was conducted to collate and categorize all pertinent information gleaned from published scientific literature on a priori defined aspects of CHIKV and its competent vectors. After developing a sensitive and specific search algorithm for the research question, seven databases were searched and data was extracted from 1920 relevant articles. Results show that CHIKV research is reported predominantly in areas after major epidemics have occurred. There has been an upsurge in CHIKV publications since 2011, especially after first reports of CHIKV emergence in the Americas. A list of hosts and vectors that could potentially be involved in the sylvatic and urban transmission cycles of CHIKV has been compiled in this scoping review. In addition, a repository of CHIKV mutations associated with evolutionary fitness and adaptation has been created by compiling and characterizing these genetic variants as reported in scientific literature.

Updates on chikungunya epidemiology, clinical disease, and diagnostics

Chikungunya virus (CHIKV) is an Aedes-borne alphavirus, historically found in Africa and Asia, where it caused sporadic outbreaks. In 2004, CHIKV reemerged in East Africa and spread globally to cause epidemics, including, for the first time, autochthonous transmission in Europe, the Middle East, and Oceania. The epidemic strains were of the East/Central/South African genotype. Strains of the Asian genotype of CHIKV continued to cause outbreaks in Asia and spread to Oceania and, in 2013, to the Americas. Acute disease, mainly comprising fever, rash, and arthralgia, was previously regarded as self-limiting; however, there is growing evidence of severe but rare manifestations, such as neurological disease. Furthermore, CHIKV appears to cause a significant burden of long-term morbidity due to persistent arthralgia. Diagnostic assays have advanced greatly in recent years, although there remains a need for simple, accurate, and affordable tests for the developing countries where CHIKV is most prevalent. This review focuses on recent important work on the epidemiology, clinical disease and diagnostics of CHIKV.

Evaluating the effectiveness of localized control strategies to curtail chikungunya

Chikungunya, a re-emerging arbovirus transmitted to humans by Aedes aegypti and Ae. albopictus mosquitoes, causes debilitating disease characterized by an acute febrile phase and chronic joint pain. Chikungunya has recently spread to the island of St. Martin and subsequently throughout the Americas. The disease is now affecting 42 countries and territories throughout the Americas. While chikungunya is mainly a tropical disease, the recent introduction and subsequent spread of Ae. albopictus into temperate regions has increased the threat of chikungunya outbreaks beyond the tropics. Given that there are currently no vaccines or treatments for chikungunya, vector control remains the primary measure to curtail transmission. To investigate the effectiveness of a containment strategy that combines disease surveillance, localized vector control and transmission reduction measures, we developed a model of chikungunya transmission dynamics within a large residential neighborhood, explicitly accounting for human and mosquito movement. Our findings indicate that prompt targeted vector control efforts combined with measures to reduce transmission from symptomatic cases to mosquitoes may be highly effective approaches for controlling outbreaks of chikungunya, provided that sufficient detection of chikungunya cases can be achieved.

Emerging Loop-Mediated Isothermal Amplification-Based Microchip and Microdevice Technologies for Nucleic Acid Detection

Rapid, sensitive, and selective pathogen detection is of paramount importance in infectious disease diagnosis and treatment monitoring. Currently available diagnostic assays based on polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) are time-consuming, complex, and relatively expensive, thus limiting their utility in resource-limited settings. Loop-mediated isothermal amplification (LAMP) technique has been used extensively in the development of rapid and sensitive diagnostic assays for pathogen detection and nucleic acid analysis and hold great promise for revolutionizing point-of-care molecular diagnostics. Here, we review novel LAMP-based lab-on-a-chip (LOC) diagnostic assays developed for pathogen detection over the past several years. We review various LOC platforms based on their design strategies for pathogen detection and discuss LAMP-based platforms still in development and already in the commercial pipeline. This review is intended as a guide to the use of LAMP techniques in LOC platforms for molecular diagnostics and genomic amplifications.

Rapid and Real-time Detection of Human Viral Infections: Current Trends and Future Perspectives

The development of technologies with rapid and sensitive detection capabilities and increased throughput have become crucial for responding to greater number of threats posed by emerging and re-emerging viruses in the recent past. The conventional identification methods require time-consuming culturing, and/or detection of antibodies, which are not very sensitive and specific. The recent advances in molecular biology techniques in the field of genomics and proteomics greatly facilitate the rapid identification with more accuracy. The real-time assays viz; SYBR green I based real time RT-PCR and RT-LAMP have been developed for rapid detection as well as typing of some of the emerging arboviruses of biomedical importance viz; Dengue, Japanese Encephalitis, Chikungunya, West Nile, SARS and Swine Flu etc. Both these techniques are capable of detection and differentiation as well as quantifying viral load with higher sensitivity, rapidity and specificity. One of the most important advantages of RT-LAMP is its field applicability, without requirement of any sophisticated equipments. The establishment of these real time molecular assays will certainly facilitate the rapid detection of viruses with high degree of precision and accuracy in future.

Rapid and real-time detection technologies for emerging viruses of biomedical importance

The development of technologies with rapid and sensitive detection capabilities and increased throughput have become crucial for responding to greater number threats posed by emerging and re-emerging viruses in the recent past. The conventional identification methods require time-consuming culturing, and/or detection of antibodies,which are not very sensitive and specific. The recent advances in molecular biology techniques in the field of genomics and proteomics greatly facilitate the rapid identification with more accuracy. We have developed two real-time assays ie., SYBR green I based real time reverse transcription polymerase chain reaction (RT-PCR) and RT-loop-mediated isothermal amplification (LAMP) assay for rapid detection as well as typing of some of the emerging viruses of biomedical importance viz. dengue, Japanese encephalitis, chikungunya, west Nile, severe acute respiratory syndrome virus (SARS) etc. Both these techniques are capable of detection and differentiation as well as quantifying viral load with higher sensitivity, rapidity, specificity. One of the most important advantages of LAMP is its field applicability, without requirement of any sophisticated equipments. Both these assays have been extensively evaluated and validated with clinical samples of recent epidemics from different parts of India. The establishment of these real time molecular assays will certainly facilitate the rapid detection of viruses with high degree of precision and accuracy in future.

Chikungunya: an overview

Chikungunya (CHIK),a mosquito borne debilitating disease,is caused by CHIK virus,an alphavirus belonging to the family Togaviridae.The sudden onset of very high fever along with rash, and severe arthralgia especially in the small joints of hands and toes are the characteristics of the disease. It was first reported from Tanzania in 1952-53 and spread subsequently to sub-Saharan Africa, South East Asia and Pacific causing large epidemics. The virus exists in three genotypes, the Asian, West African and East Central South African that are responsible for outbreaks in the respective areas.The first outbreak in Asia was in Bangkok in 1958 followed by other Asian countries. India experienced massive outbreaks of CHIK in the 1960s and early 70s mainly in cities. After a gap of 32 years an explosive outbreak of CHIK devastated the country affecting more than 1.4 million people in 13 states.The epidemic also witnessed many unusual clinico-pathological complications including CHIK associated deaths and mother to child transmission. High morbidity with severe arthralgia persisted for several months made the people mentally and physically weak. This review describes CHIK in general and highlights the various clinico-pathological aspects observed during the recent outbreak.