An update on the phylogeography and dynamics of pool 4 FMDV spread in
East and Horn of Africa
Abstract
Foot-and-mouth disease (FMD), a highly contagious viral infection
affecting cloven-hoofed animals, has significant implications for global
livestock production and trade. In this study we aimed to characterize
and describe dispersal patterns and factors affecting pool 4 serotypes
of FMD viruses (FMDV) in the East and Horn of Africa. The study area
included 12 countries i.e., Sudan, South Sudan, Eritrea, Djibouti,
Ethiopia, Somalia (Horn of Africa) and Kenya, Uganda, Tanzania, Rwanda,
Burundi, Malawi (East Africa); 1423 VP1 sequence data were used (224
serotype A, 593 serotype O, 310 SAT1 and 296 SAT2) obtained from
GenBank. Using continuous and discrete space phylogeographic models in
BEAST, we assessed viral dispersal, population dynamics, direction and
velocity modeled against environmental, human and livestock demographic
and trade data as raster files. We observed a rise in accessible
sequences in the last decade, signifying enhanced surveillance and
research endeavors but emphasizing the need for rigorous analyses to
address biases, ensuring comprehensive data collection for precise
phylogeographic inference, and highlighting the importance of genomic
surveillance given the geographical imbalance pre-1970. Higher
precipitation correlated with increased dispersal velocity for certain
serotypes, while elevation influenced the direction of viral spread.
Proximity to human and livestock populations i.e., urbanization and
agricultural activities also influenced spatial transmission dynamics.
We identified distinct viral clusters with Kenya and Sudan as major
sources for intercountry spread in the East and Northern regions,
respectively. Regional collaboration, data sharing and targeted
surveillance, informed by genomic data and environmental factors, can
aid in early outbreak detection and management.