Several factors may account for these findings of C botulinum in mascarpone, including lack of maximum limits for spore numbers in raw milk, and an insufficient ultrafiltration procedure. The heating milk-cream process 2 was inadequate to inactivate the spores of C botulinum type A. 3 Moreover, the pH, a w , and redox potential (E h ) of the final product were conducive for the viability of the pathogen. Growth of proteolytic neurotoxic clostridia occurs at 10ºC. The evidence suggests that raised storage temperature of the mascarpone at some point along the distribution chain favoured the production of botulinum toxin. This outbreak of botulism underlines the necessity to apply HACCP principles to the manufacturing process of all dairy products, and the importance of not relying solely on refrigeration for controlling the growth of C botulinum. *Paolo Aureli, Giovanna Franciosa, Manoochehr Pourshaban National Reference Centre of Botulism, Food Microbiology Laboratory, Istituto Superiore della Sanita, 00161 Rome, Italy 1 Simini B. Outbreak of foodborne botulism continues in Italy. Lancet 1996; 348: 813. 2 UNI-Ente Nazionale Italiano di Unificazione. Progetto di norma U59092140 (Mascarpone cheese: definition of specificity, composition, characteristics), 1996. 3 Hauschild AHW. Clostridium botulinum. In: Doyle MP, ed. Foodborne bacterial pathogens. New York: Marcel Dekker, 1989: 111. and according to CDC recommendations. 2,3 Food, water, and stool specimens were cultured. The kitchen, water supply, and chlorinating system of the ship were examined. We proceeded, using epidemiological methods, to identify the source of the infection. 191 (14%) passengers were interviewed with a standardised questionnaire that probed for information about symptoms, exposure to drinking water, or consumption of specific food from the ship’s menu; 71 (37%) of these passengers were ill and 120 (63%) symptom- free. A case-control study was undertaken on the ship. Cultures from food and water specimens did not yield the microorganism responsible. We did not find any leakage of the ship’s waste products into the water supply. All stool specimens cultured (n=26) yielded Shigella dysenteriae type A1. Analysis of the data showed that the main symptoms were diarrhoea, fever, and headache. We concluded that the probable transmission vectors were smoked swordfish with salted cod. Control measures for the passengers and crew members were instituted before the ship’s departure. *Achilleas Gikas, John Pediaditis, Zoi Giti, John Papadakis, Yiannis Tselentis Department of Clinical Bacteriology, Parasitology, Zoonoses, and Geographical Medicine, University of Crete, WHO Collaborating Centre, Iraklion, Crete, Greece 1 Simini B. Shigellosis strikes Italian cruise ship passengers. Lancet 1996; 348: 742. 2 Koo D, Maloney K, Tauxe R. Epidemiology of diarrheal disease outbreaks on cruise ships,, 1986 through 1993. JAMA 1996; 275: 545–47. 3 Addiss DG, Yashuk JC, Clapp DE, et al. Outbreaks of diarrhoeal illness on passenger cruise ships, 1975–85. Epidemiol Infect 1989; 103: 63–72. THE LANCET 1594 Vol 348 • December 7, 1996 Foodborne botulism in Italy SIR—Foodborne botulism is a neuroparalytic disease caused by ingestion of toxin produced by Clostridium botulinum in contaminated food. Dairy products have seldom been associated with botulism; indeed, only seven outbreaks have been reported worldwide in the past 50 years, all caused by type A and B serotypes. As Simini reports (Sept 21, p 813), 1 episodes of botulism in four southern Italy cities were brought to our attention: eight people were affected (six male, two female, ages 6–24 years). All the patients had consumed commercial acidified dairy cream (mascarpone cheese), either alone or as an ingredient of a home-prepared dessert, tiramisù, 12–24 h before onset of their symptoms. All the patients recalled that the mascarpone was malodorous. Their first symptoms (nausea, cephalagia, vomiting) were rapidly followed by neurological signs. All patients were supported by artificial ventilation and treated with trivalent antiserum. One patient died, and six were still in hospital at the time of writing (mid-October). Botulinum toxin type A was detected in two of four serum samples and two of seven rectal swabs; C botulinum type A was isolated from the faeces of all eight patients. Two brands of mascarpone, purchased in the same local stores, contained type A botulinum toxin (1866 LD 50 /g) and spores of C botulinum type A (>10 5 /g). Tiramisù consumed by two of the patients, and an unopened package of mascarpone from the same grocery shop at which the cream for the dessert had been purchased, contained type A toxin and C botulinum spores: 125 LD 50 /g and 100 000 spores/g (tiramisù) and 2495 LD 50 /g and greater than 100 000 spores/g (mascarpone), respectively. Several samples of mascarpone from different production lots, and collected from the grocery and from the manufacturing plant, were contaminated with about four spores of C botulinum type A (per gram of product). Haemorrhagic fever with renal syndrome and chronic renal failure SIR—Some patients with chronic renal failure (CRF) have a history of haemorrhagic fever with renal syndrome (HFRS), 1,2 a disease with high morbidity in Penza region (Central Volga). HFRS is caused by Puumala virus. Rodents are the primary reservoir and the bank vole ( Clethrionomys glareolus ) has been closely linked to infection. Seroprevalence studies have detected antibodies to hantaviruses in 4·9% of people in Penza region. 3 However, only 1% of seropositive men have had clinical manifestations of HFRS. 4 To clarify the impact of HFRS on rates of CRF, we analysed morbidity due to HFRS and CRF in 28 agricultural Penza regions with a population of 931700. Cases in towns with a population above 100 000 were not analysed. We divided the territory of Penza region into two provinces, depending on vegetation. Forest province lies to the east of the region and consists mostly of oak, lime, and pine trees, which provide good conditions for C glareolus . Steppe province lies to the west of the region and has cultivated land. To the northwest of the steppe area lies a forest. One administrative region is located there. This territory was not included. The ratio of forest to steppe territories is 1:1·6. In the forest province there are eight regions and more than half the territory borders five administrative regions. The rest of the 14 regions are situated on the steppe provinces territory. The mean annual morbidity rate for HFRS from January, 1991, to December, 1995, in forest province was 15·6 (median 17; range 6·3–21·1) cases per 100 000 of population compared with 2·8 (median 2·4; range 2·2–3·6) per 100 000 in steppe province. Diagnosis was confirmed by antibody to hantavirus in serum by indirect immunofluorescence. Information about 80 patients with CRF (serum creatinine level above 200 μmol/L) was analysed. The mean age was 46·2 years (median 45; range 15–76); 49 (61%) patients were men. They were observed in territorial hospitals and did not need haemodialysis. The dialysis population is not included because many patients move when haemodialysis starts. On