ENTEROVIRUSES IN ALASKA 



leading to infection of susceptible individuals in the environment. 

 Our own data, previously cited, on the recovery of Type 3 polio- 

 virus from previously- immunized children in Ft. Yukon and St. 

 Lawrence Island, comprise a modest corroboration of this infectious 

 potential of enteroviruses. Recent work indicates that other entero- 

 viruses may have this same infectious potential (Henigstet al., 1961). 

 In view of the prolonged carrier state and potential for enteric in- 

 fection of serologically- immune individuals, it is not surprising 

 that enteroviruses can persist in small semi- isolated groups of 

 arctic residents. The data graphed on Figure 2 can be interpreted 

 to indicate that endemic poliovirus infection had persisted among 

 the St. Lawrence Islanders for many years, despite the group's 

 relatively small current size of 600 individuals and less in previous 

 decades. 



Although enterovirus groups may have some basic antigenic simi- 

 larity (Halonen et al., 19 59; Melnick, 19 55; Wenner et al., 1956), they 

 are more dissimilar in antigenic composition in that an antibody 

 stimulated by infection with one kind of enterovirus may not protect 

 against infection by other types (Rosen et al., 1958a; 19 58b). The 

 earliest analyses of enteroviral antigenicity were made of polio- 

 viruses. Here it was found that Type 2 poliovirus shares antigens 

 with both Types 1 and 3, and Type 2 antibodies may protect against 

 infection by Types 1 and 3. But Types 1 and 3 have little antigenic 

 similarity and antibodies against them rarely cross-protect (Ham- 

 mon and Ludwig, 19 57; Wilt et al., 19 58; Faro, 19 59). This situation 

 is even more diversified among the large Coxsackie and ECHO 

 virus groups. Consequently, serial infections by different entero- 

 viruses occur. However, simultaneous, dual, or multiple infection 

 is rare. This is due to the mechanism of non-specific biological 

 interference mediated, according to recent discovery, by the host- 

 produced Interferon (Wagner, 1960; Baron and Isaacs, 1961), Thus, 

 one virus infection may produce a transitory non-specific reaction 

 of the host which renders the latter insusceptible for a period of 

 time to other viral infections. These phenomena, the diversity of 

 antigenicity and biological interference, in combination, tend to ex- 

 tend the period of time in which an introduced heterologous group 

 of enteroviruses remain active in a given population group, since 

 they limit superinfection but allow serial infectionby different tj^Des. 



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