The expanding spectrum of disease caused by the Lone Star Tick, Amblyomma americanum

Abstract

Ticks are remarkable vectors of a diverse and growing list of infectious agents of importance to both medical and veterinary disciplines. The tick Amblyomma americanum is one of the most frequently identified ticks in the United States with an expanding spectrum of human disease given its vast geographic range. The recently described Bourbon and Heartland viruses are likely transmitted by the Lone Star tick and are just two of the several novel tick-borne pathogens discovered in recent decades. The review will focus on these two viruses that can cause illness with similar charac- SUMMARYteristics to other diseases transmitted by the Lone Star tick. Healthcare professionals should consider these viruses in patients presenting with an ailment suggestive of a tick-born rickettsial disease that fails to improve with treatment with doxycycline. Additionally, some individuals may develop life-threatening allergic reactions triggered by the bite of the Lone Star tick.

Rickettsia amblyommatis in Ticks: A Review of Distribution, Pathogenicity, and Diversity

“…Interestingly, after two decades of increasing cases of RMSF, in 2018 and 2019 there was a slight decrease in reported cases of RMSF [ 34 ]. Similar protective effects when R. amblyommatis is coinfected with other Rickettsia species might also occur; A. americanum , the main transmitter of R. amblyommatis , also transmits other pathogens [ 205 ]. Investigations into the effects of R. amblyommatis coinfection with other tick-borne pathogens affecting virulence, transmissibility, and clinical symptoms in hosts are clearly warranted.…”

Secondary hemophagocytic lymphohistiocytosis due to Heartland virus

“…Based on tick exposure history, clinical presentation and laboratory abnormalities of leukopenia, thrombocytopenia, and hepatic transaminase elevation, suspicion was high for tickborne illness. As a Lone Star tick was removed from the patient’s body, differential diagnosis included infections transmitted by Amblyomma americanum , including ehrlichiosis, tularemia and HRTV 5. He was empirically treated with doxycycline, though clinically worsened.…”

“…The Lone Star tick ( Amblyomma americanum ) has been identified as the vector for HRTV 2 . Amblyomma americanum is the vector for multiple tickborne pathogens, including Ehrlichia chaffeensis , E. weingii , Franciscella tularensis and HRTV 5. In the USA, the incidence of tickborne illness is increasing, as ticks expand their geographic range 5.…”

“…Amblyomma americanum is the vector for multiple tickborne pathogens, including Ehrlichia chaffeensis , E. weingii , Franciscella tularensis and HRTV 5. In the USA, the incidence of tickborne illness is increasing, as ticks expand their geographic range 5. While Amblyomma americanum has historically been geographically located in the Midwest, it has now extended into the Southeastern and Northwestern USA and Canada.…”

“…While Amblyomma americanum has historically been geographically located in the Midwest, it has now extended into the Southeastern and Northwestern USA and Canada. This expansion is thought to be due to warmer temperatures associated with climate change 5…”