By: Austin Weynand, MHS
Dr. Scott Weaver studies arboviruses, particularly those borne of mosquitoes, and seeks
to understand their transmission, virulence, and emergence into new environments. There are a few with which he is most concerned, and these include the yellow fever, Zika, and chikungunya viruses. In the context of One Health, these viruses rely
heavily on human exposure to vector populations, the growth of which can shift drastically as the environment changes its shape. In the last two years, his research interests have coalesced with COVID-19 as well. He notes that the pandemic has hindered
progress in West Africa, where Dr. Weaver leads the West African Center for Emerging Infectious Diseases (WAC-EID), an organization which studies novel pathogens. Active projects in Nigeria, Senegal, and Sierra Leone have begun establishing viral surveillance with accompanying diagnostic improvements.
Of particular interest to Dr. Weaver is the transference of arboviruses from sylvatic to urban transmission cycles, a phenomenon intimately related to One Health. Yellow fever, for example, maintains a sylvatic life-cycle in Brazil, where the flavivirus
spreads reciprocally between forest species of mosquitoes and non-human primates. In 2016, spillover led to an outbreak in several Brazilian states including Minas Gerias, where over 2,000 cases and 700 deaths were attributed to the virus after two
years.1 Yet urban transmission has not been seen in Brazil since 1942.2 However, Dr. Weaver states that every spillover infection is “an opportunity for a virus to adapt for human-to-human spread.” Even with some cross-protection from
dengue in South American populations, enough low-risk transmission events can lead to amplification and then human-to-human spread. Increased commercialization of the Amazon River basin, for example, inflates the number of vector encounters.
Moreover, the poor availability and unreliability of diagnostic tests hinder progress. In some parts of the world, a person’s chance at receiving a point-of-care test are slim, and slimmer yet without external surveillance funding. Dr. Weaver
notes that the development of inexpensive, fast tests in poorer nations is needed, and related serology studies can inform viral sequencing efforts.
To Dr. Weaver’s point, the WAC-EID sites in Senegal, Nigeria and Sierra Leone are performing PCR and ELISA diagnostics to monitor for new viral infections, including monkeypox. They will also be
studying bats for prevalence of filoviruses such as Marburg and Ebolavirus, the latter of which caused deadly outbreaks in several African countries from 2014-2016.3 Sampling such populations appeals to a major tenant of One Health, in that it
targets a virus’s natural animal host in order to understand its threat. Moreover, these environmental and diagnostic studies will inform disease modeling, which in turn can inform the likelihood of an outbreak.
Dr. Scott Weaver works as the Scientific Director of the Galveston National Laboratory and as Chair and Professor in the UTMB department of Microbiology & Immunology. His research profile can be found here. More information about the WAC-EID can be found here, and information about the WRCEVA can be found here.