Mathematical Biosciences and Engineering (MBE)

Modeling co-infection of Ixodes tick-borne pathogens

Pages: 1301 - 1316, Volume 14, Issue 5/6, October/December 2017      doi:10.3934/mbe.2017067

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Yijun Lou - Department of Applied Mathematics, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China (email)
Li Liu - School of Information Engineering, Guangdong Medical University, Dongguan, Guangdong 523808, China (email)
Daozhou Gao - Mathematics and Science College, Shanghai Normal University, Shanghai 200234, China (email)

Abstract: Ticks, including the Ixodes ricinus and Ixodes scapularis hard tick species, are regarded as the most common arthropod vectors of both human and animal diseases in Europe and the United States capable of transmitting a large number of bacteria, viruses and parasites. Since ticks in larval and nymphal stages share the same host community which can harbor multiple pathogens, they may be co-infected with two or more pathogens, with a subsequent high likelihood of co-transmission to humans or animals. This paper is devoted to the modeling of co-infection of tick-borne pathogens, with special focus on the co-infection of Borrelia burgdorferi (agent of Lyme disease) and Babesia microti (agent of human babesiosis). Considering the effect of co-infection, we illustrate that co-infection with B. burgdorferi increases the likelihood of B. microti transmission, by increasing the basic reproduction number of B. microti below the threshold smaller than one to be possibly above the threshold for persistence. The study confirms a mechanism of the ecological fitness paradox, the establishment of B. microti which has weak fitness (basic reproduction number less than one). Furthermore, co-infection could facilitate range expansion of both pathogens.

Keywords:  Co-infection, tick-borne pathogens, mathematical model.
Mathematics Subject Classification:  Primary: 92D30; Secondary: 92B05.

Received: August 2016;      Accepted: December 2016;      Available Online: May 2017.