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Research Project: Assessing the Risk of Arthropod-Borne Disease in the Caribbean and the Americas (RACE Risk of Arthropod-borne diseases in the Caribbean)

Location: Research Programs

Project Number: 3022-32000-018-006-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2021
End Date: Aug 31, 2024

The goal of this project is to better understand the epidemiology of Heartwater and to assess the risk of expansion of this disease and its vector, within the Caribbean region and beyond. Except for Guadeloupe (FWI), this region is officially considered Heartwater free. A reason for the absence of notification of the disease in other countries or territories of Caribbean could be a lack of investigation and surveillance. Global warming and climate change coupled with intense circulation of human and animals or animal products may increase the potential for rickettsial tick-borne diseases such as Heartwater, currently restricted to tropical countries, will expand their geographical range. This could pose a serious threat to U.S. livestock as Amblyomma vector ticks are present in the U.S. mainland. Thus, the goal of this work is to develop tools for and to conduct surveillance for Heartwater and its tick vector in the Caribbean region in order to build robust risk assessment models.

The ARS and the Cooperator have ongoing research on vector-borne diseases affecting animals and humans. The analysis of the risk of introduction of Heartwater in a free zone will be multidisciplinary and will consist in understanding the dynamics of spread and transmission and the host-vector-bacterial interactions (i.e. bovine - vector tick A. variegatum - Ehrlichia ruminantium). The sensitivity analysis of the risk assessment will highlight the most important modules of the model in terms of variation of the risk and thus prioritizing mitigation measures if possible that will have the strongest effect. This sensitivity analysis will also emphasise the modules where the uncertainty has the most effect on the variability of the assessed risk. These grey zones will require further research. Thus, although progress has been made, Ehrlichia possesses a complex life cycle, which is still poorly understood, particularly in the tick. Novel data will be obtained with the new analytical technologies available integrated in a systems biology approach. In a complementary approach, updated knowledge of the distribution of the disease in the Caribbean area is necessary for prediction, scenarios assessment and analysis of the consequences (positive or negative) of proposed mitigation measures. The challenge specific to Ehrlichia pathogens is that, as vector-borne diseases, they require a multi-faceted approach that includes the expertise of biologists, ecologists, and veterinarians. Within the frame of this project, the findings must be synthesized in a connected multidisciplinary process.