An Exploratory Study on the Microbiome of Northern and Southern Populations of Ixodes scapularis Ticks Predicts Changes and Unique Bacterial Interactions.

Deepak Kumar,Abdulsalam Adegoke,Erika Machtinger,Monica Embers,Kelly Oggenfuss,Latoyia P Downs,Shahid Karim,Richard S Ostfeld

doi:10.3390/pathogens11020130

Abstract

The black-legged tick (Ixodes scapularis) is the primary vector of Borrelia burgdorferi, the causative agent of Lyme disease in North America. However, the prevalence of Lyme borreliosis is clustered around the Northern States of the United States of America. This study utilized a metagenomic sequencing approach to compare the microbial communities residing within Ix. scapularis populations from northern and southern geographic locations in the USA. Using a SparCC network construction model, we performed potential interactions between members of the microbial communities from Borrelia burgdorferi–infected tissues of unfed and blood-fed ticks. A significant difference in bacterial composition and diversity was found between northern and southern tick populations. The network analysis predicted a potential antagonistic interaction between endosymbiont Rickettsia buchneri and Borrelia burgdorferi sensu lato. The network analysis, as expected, predicted significant positive and negative microbial interactions in ticks from these geographic regions, with the genus Rickettsia, Francisella, and Borreliella playing an essential role in the identified clusters. Interactions between Rickettsia buchneri and Borrelia burgdorferi sensu lato need more validation and understanding. Understanding the interplay between the microbiome and tick-borne pathogens within tick vectors may pave the way for new strategies to prevent tick-borne infections.

Highlights

Vector-borne diseases affect over one billion people every year and have been expanding alarmingly in recent years [1,2,3]
This study provided an insight into the microbiome composition in unfed and partially blood-fed tick tissues, including midgut, salivary glands, and ovaries
The total number of reads obtained for whole-tick samples collected from Louisiana, New York, Oklahoma, and Pennsylvania was 2,427,191, corresponding to 2812 operational taxonomic units (OTUs), the minimum number of reads for a sample was

Summary

Introduction

Vector-borne diseases affect over one billion people every year and have been expanding alarmingly in recent years [1,2,3]. Among vector-borne diseases, Lyme disease is one of the most reported infectious diseases in the United States and corresponds to over 90% of vector-borne infections in North America [4,5]. Almost 300,000 cases of Lyme disease are reported every year in the United States, and Ixodes scapularis is known as its primary vector. Most Lyme disease cases are clustered in Northeastern and Upper Midwest States [6]. Ix. scapularis ticks are prevalent in the Southern States, but the dearth of Lyme disease infections is linked with the restricted distribution and scarcity of the primary B. burgdorferi s.l. reservoir, namely white-footed mice, Peromyscus leucopus [7].

Methods

Results

Conclusion