Outbreak of hepatitis A in Spain associated with cockles from Peru

Sixty-seven people have been diagnosed with hepatitis A infection in an
outbreak in Valencia county in Spain associated with frozen 'coquina'
(cockles) imported from Peru (1). The first cases were detected in early
October but the first cases became ill in early September. Further cases may
still be detected because clinical features of hepatitis A virus (HAV)
infection may take up to 30 days to appear (2). One hundred tonnes of cockles
had been imported into Valencia and a further 17 tonnes were discovered and
impounded in nine other autonomous regions of Spain. Reports of cases of
hepatitis have not risen unexpectedly elsewhere, suggesting that only the
cockles imported to Valencia had been contaminated.

By 11 November, 119 cases had been notified (91 confirmed serologically: IgM
antibody (anti-HAV) positive). Their median age is 26 years (range 3 to 60).
A case control study of 119 cases and 104 controls found a strong association
between illness and eating cockles (odds ratio 4.17; 95% confidence interval
2.13-8.25).

The cockles had been grilled, but presumably at either too low a temperature
or for too brief a period to kill the virus. The Health Department in
Valencia informed the Spanish Ministry of Health on 22 October about the
outbreak and the association with cockles. The Ministry of Health activated
the national system of epidemiological surveillance to prevent any further
shipments being distributed, informed officials at border checkpoints, and
warned the European Community Rapid Alert System for Foodstuffs.

Reference:

Bosch X. Cockles cause hepatitis A outbreak in Spain. Lancet 1999; 354: 1618.
(http://www.thelancet.com/)
Benenson AS. (editor). Control of communicable disease manual. Sixteenth
edition. Washington DC: American Public Health Association, 1995.