VIRAL INFECTION IN BATS 



suggesting that after a period of latency in a dormant animal, acti- 

 vated virus may reach the salivary gland more rapidly and with 

 greater frequency. In addition, quantitative studies have indicated 

 that the virus concentration in this tissue is greater than in infected 

 animals which have not experienced a period of hibernation. These 

 data are presented graphically in Figures 1 and 2, 



The results of these experiments suggest that seasonal fluctu- 

 ations' in environmental temperature may provide not only a mech- 

 anism for virus storage in this reservoir host, but may also increase 

 the chances of virus transmission by thishost.lt is recognized that 

 this concept may only apply for strains of rabies virus which 

 circulate in bat populations. 



ARTHROPOD- BORNE VIRUS INFECTIONS IN BATS 



During the course of studies on experimental rabies infection in 

 insectivorous bats, we became interested in determining how these 

 animals would react to experimental infection with other viral 

 agents, A survey of the literature (Sulkin, 1962) indicated that bats 

 have been associated in various ways with a number of disease- 

 producing agents, suggesting that these animals might act as reser- 

 voir hosts for many viruses in nature. An area of particular interest 

 to us, from an epidemiological standpoint, concerns the mechanisms 

 involved in the overwintering of the arthropod-borne viruses. Al- 

 though investigators have long sought to determine the whereabouts 

 of these viruses during the winter months intemperate zones where 

 mosquito vectors do not carry out year-round transmission cycles, 

 this void stillremains in our under standing of the complex biological 

 life cycles of these disease- producing agents. Reports of the sus- 

 ceptibility of bats to experimental infection with various arthropod- 

 borne viruses (Ito and Saito, 1952; Corristan, LaMotte and Smith, 

 1956; LaMotte, 1958) suggested this animal as an additional reser- 

 voir host, but provided only limited information as to the course of 

 the infection or the tissues involved. We were prompted, therefore, 

 to pursue studies on experimental arbovirus infection inbats to de- 



377 



