Buffalo close association matrices: Kruger National Park, South Africa

Many infectious pathogens are shared through social interactions, and
examining host connectivity has offered valuable insights for
understanding patterns of pathogen transmission across wildlife species.
African buffalo are social ungulates and important reservoirs of
directly-transmitted pathogens that impact numerous wildlife and livestock
species.   Here, we analyzed African buffalo social
networks to quantify variation in close contacts, examined drivers of
contact heterogeneity, and investigated how the observed contact patterns
affect pathogen invasion likelihoods for a wild social
ungulate.   We collected continuous association data
using proximity collars and sampled host traits approximately every two
months during a 15-month study period in Kruger National Park, South
Africa.   Although the observed herd was well connected,
with most individuals contacting each other during each bimonthly
interval, our analyses revealed striking heterogeneity in close-contact
associations among herd members. Network analysis showed that individual
connectivity was stable over time and that individual age, sex,
reproductive status, and pairwise genetic relatedness were important
predictors of buffalo connectivity. Calves were the most connected members
of the herd, and adult males were the least connected. These findings
highlight the role susceptible calves may play in the transmission of
pathogens within the herd. We also demonstrate that, at time scales
relevant to infectious pathogens found in nature, the observed level of
connectivity affects pathogen invasion likelihoods for a wide range of
infectious periods and transmissibilities.   Ultimately,
our study identifies key predictors of social connectivity in a social
ungulate and illustrates how contact heterogeneity, even within a highly
connected herd, can shape pathogen invasion
likelihoods.