Emergence of New Tickborne Infections

Fong, I. W.

Several tickborne infectious diseases such as Lyme borreliosis, ehrlichiosis, anaplasmosis, babesiosis, and others have been expanding to new endemic regions in the world for over a decade. Moreover, new pathogens transmitted by ticks have recently been recognized in animals and humans from diverse regions of the globe, widely separated in distance. These include new phleboviruses of the Bunyaviridae family, exemplified by severe fever with thrombocytopenia syndrome virus [SFTSV] recognized in China in 2010, and the Heartland virus, a closely related but distinct virus, presenting with similar clinical features and discovered in Missouri in 2012. Other newly recognized tickborne infections include a novel spirochete of the relapsing fever group, Borrelia miyamotoi, first reported to cause human infection in Russia in 2011 and subsequently discovered to cause clinical disease in the Netherlands, Japan, and the United States, with transmission by the black-legged deer tick Ixodes scapularis. In Europe a new tickborne disease, neoehrlichiosis caused by Candidatus neoehrlichia mikurensis belonging to the Anaplasmataceae family, has been described recently. Furthermore, new tickborne rickettsial infections continue to be recognized in Europe such as tickborne lymphadenopathy identified in 1997 and caused by Rickettsia slovaca. Novel tickborne infectious diseases will continue to emerge worldwide for the foreseeable future and be a challenge to the health of human populations. Innovative methods of prevention for a broad variety of tick-transmitted diseases are needed, and one approach is to develop a universal tick vaccine that can be given to animal hosts or humans.