Tuesday, April 17, 2012
101 Stanley Thomas Hall
Tulane University (Uptown)
Refreshments will be served
Rift Valley fever persistence and disease dynamics in Kruger National Park, South Africa
Rift Valley fever is an emerging zoonotic disease that is most often identified in ruminants, both free-living and domestic. It is endemic to Southern Africa, having been first identified in the region in 1951. In Southern Africa focal or large-scale epidemics occur in a variable temporal cycle of between 7 and 11 years. It is unclear how RVF virus persists during the interepidemic periods, but there are two potential nonexclusive explanations for RVF virus persistence: 1) RVF is maintained in the vector population, or 2) RVF circulates undetected in some wildlife reservoir population (Chevalier, 2010; Chevalier et al, 2004). I will first discuss evidence for these hypotheses and specifically address the role of free-living African buffalo (Syncerus caffer) in the interepidemic dynamics of RVF. I will then address coinfection dynamics, discussing how an invasive disease (Bovine Tuberculosis, BTB) might alter the interepidemic and epidemic patterns of Rift Valley fever infection, focusing on a common host species - African Buffalo. I will present cross-sectional data on 200 female African buffalo suggesting that RVF seroprevalence is elevated in buffalo with chronic BTB compared to animals uninfected with BTB. However, this pattern does not hold for those buffalo recently (and acutely) infected with BTB. Further, we show that buffalo with chronic BTB, but not acute BTB, have impaired immune responsiveness to novel antigen challenge. In combination, these results suggest that chronic BTB may result in immunosuppression in buffalo, which may make them more susceptible to viral infections such as RVF. Invasion of a non-native infection such as TB may thus secondarily alter the dynamics of native infectious diseases in free-ranging wildlife populations.
Center for Computational Science, Stanley Thomas Hall 402, New Orleans, LA 70118 firstname.lastname@example.org