Chikungunya fever is an acute febrile illness that is often associated with severe polyarthralgia in humans. The disease is caused by chikungunya virus (CHIKV), a mosquito-borne alphavirus. Since its ...reemergence in 2004, the virus has spread throughout the tropical world and several subtropical areas affecting millions of people to become a global public health issue. Given the significant disease burden, there is a need for medical countermeasures and several vaccine candidates are in clinical development. To characterize the global epidemiology of chikungunya and inform vaccine development, we undertook a systematic literature review in MEDLINE and additional public domain sources published up to June 13, 2020 and assessed epidemiological trends from 1999 to 2020. Observational studies addressing CHIKV epidemiology were included and studies not reporting primary data were excluded. Only descriptive analyses were conducted. Of 3,883 relevant sources identified, 371 were eligible for inclusion. 46% of the included studies were published after 2016. Ninety-seven outbreak reports from 45 countries and 50 seroprevalence studies from 31 countries were retrieved, including from Africa, Asia, Oceania, the Americas, and Europe. Several countries reported multiple outbreaks, but these were sporadic and unpredictable. Substantial gaps in epidemiological knowledge were identified, specifically granular data on disease incidence and age-specific infection rates. The retrieved studies revealed a diversity of methodologies and study designs, reflecting a lack of standardized procedures used to characterize this disease. Nevertheless, available epidemiological data emphasized the challenges to conduct vaccine efficacy trials due to disease unpredictability. A better understanding of chikungunya disease dynamics with appropriate granularity and better insights into the duration of long-term population immunity is critical to assist in the planning and success of vaccine development efforts pre and post licensure.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In December 2013, the first locally-acquired chikungunya virus (CHIKV) infections in the Americas were reported in the Caribbean. As of May 16, 55,992 cases had been reported and the outbreak was ...still spreading. Identification of newly affected locations is paramount to intervention activities, but challenging due to limitations of current data on the outbreak and on CHIKV transmission. We developed models to make probabilistic predictions of spread based on current data considering these limitations.
Branching process models capturing travel patterns, local infection prevalence, climate dependent transmission factors, and associated uncertainty estimates were developed to predict probable locations for the arrival of CHIKV-infected travelers and for the initiation of local transmission. Many international cities and areas close to where transmission has already occurred were likely to have received infected travelers. Of the ten locations predicted to be the most likely locations for introduced CHIKV transmission in the first four months of the outbreak, eight had reported local cases by the end of April. Eight additional locations were likely to have had introduction leading to local transmission in April, but with substantial uncertainty.
Branching process models can characterize the risk of CHIKV introduction and spread during the ongoing outbreak. Local transmission of CHIKV is currently likely in several Caribbean locations and possible, though uncertain, for other locations in the continental United States, Central America, and South America. This modeling framework may also be useful for other outbreaks where the risk of pathogen spread over heterogeneous transportation networks must be rapidly assessed on the basis of limited information.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Eastern equine encephalitis virus (EEEV; Family Togaviridae), is an endemic pathogen first isolated in 1933 with distribution primarily in the eastern US and Canada. The virus has caused periodic ...outbreaks in both humans and equines along the eastern seaboard and through the southern coastal states. While the outbreaks caused by EEEV have been sporadic and varied geographically since the discovery of the virus, it has continued to expand its range moving into the Midwest states as well. Additionally, one of the largest outbreaks was recorded in 2019 prompting concerns that outbreaks were becoming larger and more frequent. Because the virus can cause serious disease and because it is transmissible by both mosquitoes and aerosol, there has been renewed interest in identifying potential options for vaccines. Currently, there are no licensed vaccines and control relies completely on the use of personal protective measures and integrated vector control which have limited effectiveness for the EEEV vectors. Several vaccine candidates are currently being developed; this review will describe the multiple options under consideration for future development and assess their relative advantages and disadvantages.
Chikungunya virus is a mosquito-borne virus that has been responsible for over 2 million human infections during the past decade. This virus, which previously had a geographical range primarily ...restricted to sub-Saharan Africa, the Indian subcontinent and South East Asia, has recently moved to subtropical latitudes as well as the western hemisphere. This expansion into novel habitats brings unique risks associated with further spread of the virus and the disease it causes.
Chikungunya fever is an acute febrile illness associated with severe, often debilitating polyarthralgias. The disease is caused by Chikungunya virus (CHIKV), an arthropod-borne virus that is ...transmitted to humans primarily via the bite of an infected mosquito. Since a re-emergence of CHIKV in 2004, the virus has spread into novel locations, such as Europe, and has led to millions of cases of disease throughout countries in and around the Indian Ocean. The risk of importation of CHIKV into new areas is ever present because of the high attack rates associated with the recurring epidemics, the high levels of viremia in infected humans, and the worldwide distribution of the vectors responsible for transmitting CHIKV. In this review, we will characterize the epidemiology and global expansion of CHIKV, describe the clinical features and laboratory testing for the disease, and discuss priorities for further studies needed for effective disease control and prevention.
Western equine encephalitis virus (WEEV; Alphavirus) is a mosquito-borne virus that can cause severe encephalitis in humans and equids. Previous studies have shown that intranasal infection of ...outbred CD-1 mice with the WEEV McMillan (McM) strain result in high mortality within 4 days of infection. Here in vivo and ex vivo bioluminescence (BLM) imaging was applied on mice intranasally infected with a recombinant McM virus expressing firefly luciferase (FLUC) to track viral neuroinvasion by FLUC detection and determine any correlation between BLM and viral titer. Immunological markers of disease (MCP-1 and IP-10) were measured and compared to wild type virus infection. Histopathology was guided by corresponding BLM images, and showed that neuroinvasion occurred primarily through cranial nerves, mainly in the olfactory tract. Olfactory bulb neurons were initially infected with subsequent spread of the infection into different regions of the brain. WEEV distribution was confirmed by immunohistochemistry as having marked neuronal infection but very few infected glial cells. Axons displayed infection patterns consistent with viral dissemination along the neuronal axis. The trigeminal nerve served as an additional route of neuroinvasion showing significant FLUC expression within the brainstem. The recombinant virus WEEV.McM.FLUC had attenuated replication kinetics and induced a weaker immunological response than WEEV.McM but produced comparable pathologies. Immunohistochemistry staining for FLUC and WEEV antigen showed that transgene expression was present in all areas of the CNS where virus was observed. BLM provides a quantifiable measure of alphaviral neural disease progression and a method for evaluating antiviral strategies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chikungunya virus has been causing a series of ongoing epidemics around the globe for the past 12 years. During that time, estimates indicate that >4 million cases occurred worldwide. Despite the ...magnitude of these outbreaks and the broad interest in understanding the virus and disease, significant gaps still exist in our knowledge base. An in-depth understanding of the basic virological elements that can affect the epidemiology of the agent is critical for future development of control and treatment products. This work describes how knowledge of various viral genetic and structural elements has begun to advance the development of vaccines and therapeutics and suggests that further knowledge is needed to provide additional options.
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