Proposal for Sequencing the Genome of the Tick, Ixodes scapularis

This proposal represents the cooperative efforts of the international tick research community to develop the first large scale genomic analysis of a medically significant tick, namely Ixodes scapularis. Ticks transmit the greatest variety of human and animal pathogens of any arthropod vector and are second only to mosquitoes as vectors of human disease (Fivaz et al., 1992; Sonenshine and Mather, 1994). Diseases transmitted by blood feeding ixodid ticks (subphylum Chelicerata; class Arachnida; subclass Acari; family Ixodidae) are global medical and veterinary health problems (Sonenshine, 1993) and include a wide variety of bacterial, rickettsial, viral and protozoan diseases. Other forms of pathogenesis attributed to ticks include anemia, dermatosis, toxemia and The resurgence of LD and the emergence of other tick-borne diseases such as human granulocytic anaplasmosis pose increasing public health concerns. Since the discovery of the causative agent of LD, Borrelia burgdorferi, fifteen previously unrecognized tick-borne bacterial pathogens have been described (Parola and Raoult, 2001). Furthermore, due to their efficiency as vectors of a wide variety of pathogens, broad vertebrate host range and worldwide distribution (Sonenshine, 1991), ixodid ticks are recognized as potential vectors of a number of pathogens considered to be possible bioterrorism agents for use against humans and livestock including Crimean-Congo hemorrhagic fever virus, Rickettsia rickettsii (Rocky Mountain Spotted Fever), the tick-borne encephalitis complex of flaviviruses (Central European tick-borne encephalitis, Far Eastern tick-borne encephalitis, Siberian tick-borne encephalitis, Kyasanur forest disease and Omsk hemorrhagic fever), Coxiella burnetii (Q Fever) and Francisella tularensis In the United States, I. scapularis is the most important tick species from a human health perspective. Ixodes scapularis transmits LD in the northeastern and north-central US, HGA and babesiosis and possibly the flaviviral agent of Powassan encephalitis (POW) which is related to West Nile virus. Recent studies by Anderson et al., (2003) also suggest that West Nile virus can be transmitted trans-stadially by I. scapularis although vector competence has yet to be established. LD is arguably one of the most important vector borne diseases in the US, Europe and Asia. Over 17, 000 positive LD cases were reported to the US in 2000 (Centers for Disease Control and Prevention, 2002). LD and other tick-borne diseases have important long term health consequences. Of further concern is the fact that the incidence and geographic spread of LD and other tick-borne disease are increasing and many cases are suspected to be vastly under-reported or misdiagnosed (Walker, 1988). Ixodes scapularis is …