Identifying Risk Factors of Anaplasma Infection in Plains Zebra of Etosha National Park, Namibia
Author: Madison Stahle
Major: Animal and Veterinary Sciences
Graduation Year: 2021
Thesis Advisor: Pauline Kamath
Description of Publication: Anaplasmosis is a tick-borne illness that is caused by bacteria from the genus Anaplasma which infect the blood cells of their hosts. Anaplasmosis can affect the health and life expectancy of zebra, however, little is known about what makes drives the variability in infection within this species. The purpose of this study is to (1) determine the prevalence, and (2) identify risk factors for Anaplasma infections in plains zebra (Equus quagga) from the Etosha National Park, Namibia, including whether Anaplasma infections correlate with other parasite infections (ectoparasites and gastrointestinal parasites).Other possible risk factors for Anaplasma infection that are investigated here include age, sex, and major histocompatibility (MHC) genotype. I used polymerase chain reaction to detect the presence of Anaplasma species in DNA extracted from blood samples. I used generalized linear models to determine the relationships between possible individual risk factors and infected individuals. Sanger sequencing was used to identify Anaplasma strains present in these samples to the species level, and a phylogenetic analysis was performed to characterize the genetic relationships between strains found in zebra with strains from other species, including livestock, humans, and ticks. This study revealed that 35.9% of ENP zebra were infected with Anaplasma, and out of the risk factors evaluated, only age was significantly associated with Anaplasma infection, showing that as age increased the probability of Anaplasma infection decreased. Sequencing data revealed that there were 3 variant strains, and the Anaplasma species in this population is 99.7% similar to A. platys. These findings will be important in helping researchers better understand the risks of Anaplasma infections in plains zebra and how these infections correlate with other parasite infections. These results could also be helpful in studying risk factors of other diseases in the population in the future.
Location of Publication:
URL to Thesis: https://digitalcommons.library.umaine.edu/honors/697/