Brett R. Ellis

Bio: Brett R. Ellis is an academic researcher from Tulane University. The author has contributed to research in topics: Yellow fever & Simian immunodeficiency virus. The author has an hindex of 4, co-authored 4 publications receiving 105 citations.

The enigma of yellow fever in East Africa.

Abstract: Despite a safe and effective vaccine there are approximately 200000 cases including 30000 deaths due to yellow fever virus (YFV) each year of which 90% are in Africa The natural history of YFV has been well described especially in West Africa but in East Africa yellow fever (YF) remains characterised by unpredictable focal periodicity and a precarious potential for large epidemics Recent outbreaks of YF in Kenya (1992-1993) and Sudan (2003 and 2005) are important because each of these outbreaks have involved the re-emergence of a YFV genotype (East Africa) that remained undetected for nearly 40 years and was previously unconfirmed in a clinically apparent outbreak In addition unlike West Africa and South America YF has yet to emerge in urban areas of East Africa and be vectored by Aedes (Stegomyia) aegypti This is a significant public health concern in a region where the majority of the population remains unvaccinated This review describes historical findings highlights a number of disease indicators and provides clarification regarding the natural history recent emergence and future risk of YF in East Africa

Yellow fever virus susceptibility of two mosquito vectors from Kenya, East Africa

Abstract: Yellow fever is an unpredictable disease of increasing epidemic threat in East Africa. Aedes (Stegomyia) aegypti has never been implicated as a vector in this region and recent outbreaks have involved a newly emerging virus genotype (East African). To better understand the increasing epidemic risk of yellow fever in East Africa, this study is the first to investigate the vector competence for an emerging East African virus genotype in Kenyan A. aegypti sensu latu (s.l) and A. (Stegomyia) simpsoni s.l. mosquito species. Using first filial generation mosquitoes and a low passage yellow fever virus, this study demonstrated that although A. aegypti s.l. is a competent vector, A. simpsoni s.l. is likely a more efficient vector.

Seroprevalence of simian immunodeficiency virus in wild and captive born Sykes' monkeys (Cercopithecus mitis) in Kenya

Abstract: Background The Sykes' monkey and related forms (Cercopithecus mitis) make up an abundant, widespread and morphologically diverse species complex in eastern Africa that naturally harbors a distinct simian immunodeficiency virus (SIVsyk). We carried out a retrospective serological survey of SIV infection from both wild and captive Sykes' monkeys from Kenya. We compared two commercially available, cross-reactive ELISA tests using HIV antigens with a novel SIVsyk antigen-specific Western blot assay and analyzed the data by origin, subspecies, age and sex.

Spatiotemporal distribution of diurnal yellow fever vectors (Diptera: Culicidae) at two sylvan interfaces in Kenya, East Africa.

Abstract: Yellow fever virus (YFV) remains a significant public health threat in sub-Saharan Africa in which 90% of the estimated 200,000 cases occur annually. In East Africa, human cases of YFV are characterized by unpredictable focal periodicity, lengthy inter-epidemic periods, and a precarious potential for large epidemics. YFV had remained undetected in this region for nearly 40 years until emerging in Kenya in 1992–93 and more recently in Sudan during 2003 and 2005. From an ecological perspective the emergence and epidemiological outcomes associated with YFV, and related vector-borne diseases, are critically dependent upon the underlying vector ecology at a local scale. The study here was aimed at defining the dynamics of important vector interactions at two important sites in Kenya with previous YFV or related arbovirus activity. The temporal abundance, spatial distribution, and human host seeking behavior of diurnal man-landing mosquito species along sylvan interfaces were investigated. A number of ...

Ivermectin is a potent inhibitor of flavivirus replication specifically targeting NS3 helicase activity: new prospects for an old drug

Abstract: Objectives Infection with yellow fever virus (YFV), the prototypic mosquito-borne flavivirus, causes severe febrile disease with haemorrhage, multi-organ failure and a high mortality. Moreover, in recent years the Flavivirus genus has gained further attention due to re-emergence and increasing incidence of West Nile, dengue and Japanese encephalitis viruses. Potent and safe antivirals are urgently needed.

Understanding the benign nature of SIV infection in natural hosts

Abstract: In striking contrast to HIV infection, natural SIV infection of African nonhuman primates is asymptomatic and usually does not induce significant CD4+ T cell depletion despite high levels of virus replication. Recently, significant progress has been made in understanding the mechanisms underlying the remarkable difference in infection outcome between natural and nonnatural HIV/SIV hosts. These advances include the identification of limited immune activation as a key factor protecting natural SIV hosts from AIDS and the discovery of low CC chemokine receptor 5 expression on CD4+ T cells as a specific and consistent immunologic feature in these animals. Further elucidation of the pathways by which the differences in immune activation between natural and nonnatural hosts are manifest holds promise for the design of novel therapeutic approaches to HIV infection.