**Acknowledgements**

The authors appreciate the efforts of the participants who gave their blood and stool specimens for this study. Special thanks to Department of Microbiology, Nasarawa State University, Keffi, South Atlantic Petroleum Medical Center Keffi, and the Federal Medical Centre, Keffi, Nigeria for their support and technical advices. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
