Neutralization of Poliomyelitis Virus by the Serum of Native Chinese of Peiping. ∗

Abstract

The studies of Frost, 1 Aycock, 2 and others on the epidemiology of acute anterior poliomyelitis have led to the opinion that the virus is more widely distributed than the incidence of clinical cases indicates. Aycock and Kramer 3 found that 86% of serums from 21 normal adult persons of Atlanta, Georgia, possessed virucidal properties; these results suggest that immunity as measured by the neutralization test is extensively present in the warm southern latitudes, as other investigations have shown in the cooler northern latitudes. Recent investigations into the incidence of neutralizing serums in tropical and subtemperate regions where clinical poliomyelitis is uncommon have extended the findings of Aycock and Kramer. Hudson and Litterer 4 observed that 84% of the serums of 25 normal adults of Nashville, Tennessee, were capable of neutralizing the virus; Soule and McKinley 5 found that the serums of 8 adult Porto Ricans without history of attack or exposure to the disease were virucidal in every instance; and we 6 recently reported that 18 out of 19 serums from normal Liberian negroes were able to inactivate the virus.

To obtain data on the extent of immunity in cooler climates where the occurrence of frank cases of the disease is seldom reported, we turned to the examination of the serum of native Chinese. Zia 7 writes that “among 25,000 admissions to the Peiping Union Medical College Hospital, there has been only one diagnosis of this disease, ”but further reports that he recently observed several cases in the acute stage. He adds that, while it is unlikely that epidemics of poliomyelitis in China have been overlooked, it does seem probable that the apparent infrequency of sporadic cases may rest on failure to recognize the manifestations of the disease.