coast of New Jersey, developed infectious hepatitis. In N.J. and eastern 

 Pennsylvania, among counties reporting 10 or more cases during the period, 

 8 counties had a history of raw clam ingestion 10 to 6 days prior to onset 

 in more than 20% of reported cases. These were Atlantic, Burlington, and 

 Camden Counties in N.J. and Bucks, Chester, Delaware, Montgomery, and 

 Philadelphia Counties, Pa. Previous surveys in coastal areas showed that 

 no more than 20% of people ate raw clams in a 2-month period. Thus, this 

 concentration of cases suggested that raw clams were a vehicle of infection. 

 In 115 cases one or more restaurants or fish markets were identified as place 

 of purchase of raw clams. Suppliers were known in 110 of these cases. The 

 source in many cases was the Pleasantville, N.J. area. Other clams 

 implicated came from shippers from R.I. to Va. In New Haven, Conn., in 

 January 1964, infectious hepatitis cases increased, and so did the proportion 

 of cases with a history of raw clam ingestion. An investigation gave the 

 following preliminary results: from 1 Nov 1963 to 1 March 1964, Connecticut 

 had 245 cases of viral hepatitis and Rhode Island 68. About half the cases 

 in New Haven and Fairfield Counties, Conn, had eaten raw clams during the 

 period. In other Connecticut counties no more than 15% of hepatitis cases 

 had eaten raw clams, which is about "normal". Only 13% of New Haven and 

 Fairfield County cases had a history of personal contact with a known 

 hepatitis case during 2 months prior to onset; 31% of the balance of Conn, 

 cases had known contacts. Onset of hepatitis cases in patients who had 

 eaten raw clams corresponded with the known incubation period (median number 

 of days 30-34). Most clams had come from Narragansett Bay, R.I. from a 

 single shipper, or at most from this and a second shipper. - J.L.M. 



1357 



Mosley, J. W. 1964. 



IV. Shellfish-associated infectious hepatitis. A. Clam-associated infectious 

 hepatitis - New Jersey and Pennsylvania: Follow-up report. Center for Disease 

 Control, Hepatitis Surveillance Rept. 19: 30-32, with tables and figs. 



Author's name, date, and journal do not appear in the xerox copy supplied 

 through interlibrary loan. These were taken from the literature reference 

 which brought the paper to our attention and the computer memo attached to 

 the copy. The epidemic of infectious hepatitis in Southern N.J. and eastern 

 Pa. associated with ingestion of raw clams from Atlantic County appeared to 

 have stopped. Between 29 Sept 1963 and 25 Apr 1964 surveillance information 

 was collected on 1,039 cases of hepatitis in the area. Raw clam ingestion 

 10 to 60 days prior to onset of symptoms was reported for 252 cases. Of these 

 252 cases, 194 were traced directly or indirectly to shippers in Atlantic 

 County. Many purchases were made in restaurants, and repeated shipments of 

 contaminated clams were suggested. Cases of infectious hepatitis from Kansas, 

 Michigan, Nebraska, District of Columbia, and Missouri were linked with the 

 same sources. 



B. Clam-associated infectious hepatitis - Connecticut: Follow-up report: 32-34. 



From 1 Nov 1963 to 15 June 1964 the State of Connecticut had at least 489 cases 

 of viral hepatitis. Surveillance data were available on 455. Raw clam 

 ingestion 10 to, 60 days prior to onset of symptoms was reported in 119 cases. 

 All but 8 had obtained clams from restaurants and markets in Conn. The 

 epidemic came in 2 waves, Jan to Mar, and late Apr to May. Both waves 

 reflected real increases in proportion of clam-associated cases. Only 8% of 

 well persons 20 years and older who lived in the same block as the hepatitis 

 cases had consumed raw clams, whereas 26% of hepatitis cases had. Clams 

 associated with most cases were traced directly or indirectly to 2 dealers. 

 The clams presumably came from Narragansett Bay, R.I. It was very unlikely 

 that the clams had been harvested illegally. The length of the epidemic 

 suggested that several shipments of contaminated clams had been made. It was 

 concluded that shellfish-associated epidemics of infectious hepatitis may be 

 relatively common, but rarely produce enough cases to attract attention of 

 health authorities. - J.L.M. 



381 



