Measuring the burden of arboviral diseases: the spectrum of morbidity and mortality from four prevalent infections. Popul Health Metr 9:1

Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, USA. .
Population Health Metrics (Impact Factor: 2.11). 01/2011; 9(1):1. DOI: 10.1186/1478-7954-9-1
Source: PubMed


Globally, arthropod-borne virus infections are increasingly common causes of severe febrile disease that can progress to long-term physical or cognitive impairment or result in early death. Because of the large populations at risk, it has been suggested that these outcomes represent a substantial health deficit not captured by current global disease burden assessments.
We reviewed newly available data on disease incidence and outcomes to critically evaluate the disease burden (as measured by disability-adjusted life years, or DALYs) caused by yellow fever virus (YFV), Japanese encephalitis virus (JEV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV). We searched available literature and official reports on these viruses combined with the terms "outbreak(s)," "complication(s)," "disability," "quality of life," "DALY," and "QALY," focusing on reports since 2000. We screened 210 published studies, with 38 selected for inclusion. Data on average incidence, duration, age at onset, mortality, and severity of acute and chronic outcomes were used to create DALY estimates for 2005, using the approach of the current Global Burden of Disease framework.
Given the limitations of available data, nondiscounted, unweighted DALYs attributable to YFV, JEV, CHIKV, and RVFV were estimated to fall between 300,000 and 5,000,000 for 2005. YFV was the most prevalent infection of the four viruses evaluated, although a higher proportion of the world's population lives in countries at risk for CHIKV and JEV. Early mortality and long-term, related chronic conditions provided the largest DALY components for each disease. The better known, short-term viral febrile syndromes caused by these viruses contributed relatively lower proportions of the overall DALY scores.
Limitations in health systems in endemic areas undoubtedly lead to underestimation of arbovirus incidence and related complications. However, improving diagnostics and better understanding of the late secondary results of infection now give a first approximation of the current disease burden from these widespread serious infections. Arbovirus control and prevention remains a high priority, both because of the current disease burden and the significant threat of the re-emergence of these viruses among much larger groups of susceptible populations.

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    • "Arboviruses (arthropod-borne viruses), which have exhibited a dramatic global resurgence or emergence (Gubler, 2002), represent a significant global health challenge (Labeaud et al., 2011). These include Phleboviruses, in the family Bunyaviridae, whose notable members include the mosquito-vectored Rift Valley fever virus, the sandfly-vectored Toscana virus, and the tickvectored Uukuniemi virus (King et al., 2012). "
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    ABSTRACT: Arthropod-borne viruses significantly impact human health. They span multiple families, all of which include viruses not known to cause disease. Characterizing these representatives could provide insights into the origins of their disease-causing counterparts. Field-caught Aedes aegypti mosquitoes from Nakhon Nayok, Thailand, underwent metagenomic shotgun sequencing to reveal a Bunyavirus closely related to Phasi Charoen (PhaV) virus, isolated in 2009 from Ae. aegypti near Bangkok. Phylogenetic analysis of this virus suggests it is basal to the Phlebovirus genus thus making it ideally positioned phylogenetically for understanding the evolution of these clinically important viruses. Genomic analysis finds that a gene necessary for virulence in vertebrates, but not essential for viral replication in arthropods, is missing. The sequencing of this phylogenetically-notable and genomically-unique Phlebovirus from wild mosquitoes exemplifies the utility and efficacy of metagenomic shotgun sequencing for virus characterization in arthropod vectors of human diseases.
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    • "Its distribution has, in recent years expanded and is expected to spread more widely geographically with anticipated changes in climate, land use (particularly rice and pig farming and urbanization), and access to health care [4], [5]. The high case fatality rate, high rate of severe long lasting neurological symptoms and the majority of deaths occurring in children make JE a major public health problem [6]. JE is not homogenously distributed in Nepal. "
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    • "In some cases the disease can progress to a second phase which is characterized by a chronic rheumatic syndrome (Schilte et al., 2013). Although Chikungunya fever is usually not fatal, its severity is due to the severe arthralgia that may persist for weeks or years, and the joint pain is real burden because of its serious negative impact on the individual and on the affected communities (Gerardin et al., 2011; Labeaud et al., 2011). Thus, understanding the mechanism of CHIKV-induced chronic arthritis is important to understanding the pathology of the disease. "
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    ABSTRACT: Fibroblast-like synoviocytes are known to migrate from joint to joint and are proposed to be one of the key players in the inflammatory cascade amplification in rheumatoid arthritis patients. In the recent CHIKV epidemic, patients developed arthritis-like syndrome and the synoviocyte is one of the suspected players in CHIKV-induced polyarthritis. Thus, to learn more on this syndrome, the responses of fibroblast-like synoviocytes to chikungunya virus (CHIKV) infection, and the interaction between CHIKV-infected synoviocytes and phagocytes, were investigated. Primary human fibroblast-like synoviocyte (HFLS) cultures were infected with clinical isolates of CHIKV at an MOI of 0.001pfu/cell. Data indicated that HFLS are permissive to CHIKV replication, generating peak titers of 10(5) to 10(6) pfu/ml. Interestingly, CHIKV- infected HFLS cultures secreted mainly the mediators that are responsible for phagocytes recruitment and differentiation (RANKL, IL-6, IL-8 and MCP-1) but not arthritogenic mediators (TNF-α, IL-1β, MMP-1, MMP-2 or MMP-13). The interaction between CHIKV-infected synoviocytes and phagocytes was studied using UV-irradiated, CHIKV-infected HFLS supernatant. Data revealed that supernatants from CHIKV-infected HFLS cultures not only induced migration of primary human monocytes, but also drove monocytes/macrophages into osteoclast-like cells. These differentiated osteoclast-like cells produced high levels of TNF-α and IL-6, principal mediators of arthritis. This data suggests a potential interplay between infected HFLS and recruiting phagocytes which may responsible for the arthralgia/arthritis in CHIKV-infected patients.
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