Blocking pathogen transmission at the source: reservoir targeted OspA-based vaccines against Borrelia burgdorferi

Abstract

Control strategies are especially challenging for microbial diseases caused by pathogens that persist in wildlife reservoirs and use arthropod vectors to cycle amongst those species. One of the most relevant illnesses that pose a direct human health risk is Lyme disease; in the US, the Centers for Disease Control and Prevention recently revised the probable number of cases by 10-fold, to 300,000 cases per year. Caused by Borrelia burgdorferi, Lyme disease can affect the nervous system, joints and heart. No human vaccine is approved by the Food and Drug Administration. In addition to novel human vaccines, new strategies for prevention of Lyme disease consist of pest management interventions, vector-targeted vaccines and reservoir-targeted vaccines. However, even human vaccines can not prevent Lyme disease expansion into other geographical areas. The other strategies aim at reducing tick density and at disrupting the transmission of B. burgdorferi by targeting one or more key elements that maintain the enzootic cycle: the reservoir host and/or the tick vector. Here, I provide a brief overview of the application of an OspA-based wildlife reservoir targeted vaccine aimed at reducing transmission of B. burgdorferi and present it as a strategy for reducing Lyme disease risk to humans.

Methods to Prevent Tick Bites and Lyme Disease

“…88 However, this approach has only shown modest impact in experimental studies where a single host was targeted. 89 It is likely that the complex ecology of Lyme disease limits impact when vaccination targets a single host. 90,91 However, it is possible that targeting a broader range of potential reservoir hosts might enhance impact.…”

Tick-Pathogen Interactions and Vector Competence: Identification of Molecular Drivers for Tick-Borne Diseases

“…Targeting some of the similar mechanisms used by the pathogens for infection and transmission by ticks may be used to develop strategies against multiple tick-borne diseases. As shown for B. burgdorferi OspA (Gomes-Solecki, 2014), pathogen-derived proteins involved in interactions with tick cells and playing a role during infection provide targets for development of novel control strategies for pathogen infection and transmission. Similarly, tick-derived antigens such as SUB involved in different biological processes may be used to reduce vector infestations and pathogen infection in ticks feeding on immunized animals (de la Fuente and Contreras, 2015).…”

Arbovirosis and potential transmission blocking vaccines

“…Incidence of Powassan encephalitis has increased in the last fifteen years but it is still a ‘neglected’ tick-borne disease in North America [ 148 ]. Most research on this tick species is directed to stop other bacterial or parasitic diseases transmitted by this species and yet there is little research on transmission blocking vaccine being designed to stop POWV transmission [ 149 ]. The ANTIDotE approach may also lead to POWV candidates, especially because, POWV is transmitted imbibed in tick saliva and transmission occurs in the first hours of blood feeding [ 150 ].…”