Bari in the seventh cholera pandemic
|Gazzetta del Mezzoggiorno, Bari, Italy, 31st August 1973. Photo Courtesy of Prof. Salvatore Barbuti’s private collection.|
It all began on a quiet warm afternoon in August 1973 when an infectious diseases specialist called his friend in public health and hesitantly asked for a test on stool sample for a patient whom he believed could be infected with cholera. The public health man laughed and asked his colleague if he had been too long in the sun. For there had been no cholera in Italy since 1911, and the present generation knew this disease only from Asian adventure books or news of epidemics in far-away countries.
But the public health doctor became quite perplexed when a few minutes after that phone call a sample brought into the laboratory looked as what the textbooks described as “rice water feces”. Examination by microscopy on 31 August and then by culture using a specific antiserum confirmed the presence of Vibrio Cholerae biotype El Tor, which had replaced the classic Vibrio in almost all the cases of the seventh pandemic. In the geographical areas involved it was the only one to uphold the cholera endemicity.
Until 1926 cholera had been confined to Asia except for epidemics in 1946 in Japan and in 1947 in Egypt and Syria. But a new worldwide epidemic, number seven, had broken out in 1961, and by the year 2001 it would have spread to some fifty-eight countries, some becoming endemic areas.
In 1973 cholera struck the Mediterranean area. Already that summer a few cases of cholera had been reported from Tunisia and Algeria, probably because of the extreme drought that had affected those countries. There were also some twenty-five isolated cases in UK, France, Sweden, and Germany. But in August of that year the cholera epidemic spread to Italy, especially in the south – Campania and Apulia and also Sardinia, affecting 277 persons, of whom twenty-four died.
Of all cases 255 were in Campania and Apulia (seven deaths), and thirteen in Sardinia. In Bari the epidemic lasted from August 28 to September 17, with a total of 110 bacteriologically confirmed cases. The peak incidence was in the first week between August 28 and September 6, when seventy-six people became sick and died, all elderly suffering from chronic diseases. This low case fatality rate of 5.5% was due to prompt treatment, but also to the low virulence of Vibrio El Tor compared to the more common Vibrio cholera. Within seven days of clinical recovery all patients had negative cultures, except for one who continued to eliminate the cholera bacteria even fifty days after recovery.
The patient was a fifty-year old man, father of seven (luckily, none of whom developed the disease), and guardian of one of the football grounds in the city of Bari, where by a strange coincidence the public health doctor who detected the first cases of cholera had played in the junior championships. This convalescent carrier, remembering the doctor, went through the hospital corridors insisting on being discharged. In the end the doctor, considering the needs of the large, humble patient’s family, the ongoing environmental interventions, and the strict recommendations to the guardian on how to behave with his numerous children, decided to give a negative diagnosis on the subsequent check-ups. In this way, the doctor broke one of the very basic rules of prevention regarding infectious diseases. But in the following months there were no consequences of infection in his family, nor in people close to them who were subject to close tacit observation.
But what was the source of the outbreak in the Apulia region (and also in Campania) in the same period? It is useful to remember that cholera is transmitted mainly through the environment and the water, but very rarely person to person, especially in developed countries. It was immediately possible to exclude drinking water and widely consumed foods such as milk, considering the limited number of cases in both regions (approximately 1 per 30,000 inhabitants). Therefore, the investigation was directed towards a more restricted food source: raw seafood. It was in fact found that raw seafood had been consumed before the onset of the disease in 58% of cases in Apulia, 39% in Campania, and in almost all the cases in Sardinia.
The possibility of contaminated imported seafood being the main cause of the epidemic seemed less likely. Although to this day Taranto city still has large mussel farms, most mussels imported into Apulia came from Greece and Spain, not from North Africa, in which case the spread of the disease would have been different. Moreover, many of the infected patients had not eaten raw seafood. So it seemed more likely that the initial outbreak was caused by carriers from endemic countries (tourists, seafarers, fishermen), resulting in the elimination of the cholera bacteria in waste water and subsequently into the sea (in 1973 in Bari the sewers flowed directly into the sea along the entire urban coast), causing pollution and contaminating the seafood on sale at fish markets.
The measures immediately adopted included a ban on the sale of seafood and strict and continuous controls on the possible vehicles of infection such as sewage, sea water, mussels, and vegetables, so that by March 1974 all but cultures six were negative for Vibrio El Tor. But the most decisive intervention for the interruption of transmission of the cholera bacteria was chlorination of the slurry, an expensive operation which effectively destroys the bacillus.
Serious damage was done by the epidemic to the people of Apulia, giving it a third world image resulting in economic dislocation, collapse of tourism, and a prohibition on imports of products from the area. Tons of healthy mussels were destroyed even though these were not the direct perpetrators, and so were many mussel farms. Fish was sold for three long weeks at very low prices or given away, resulting in great economic damage.
After three weeks cholera was eliminated from the city. The lesson was learned, resulting in a series of environmental renewals, namely the adaptation of the sewage system and the creation of farms and mussel housing with particular attention to the quality of sea water used for the shellfish. The most significant action was the construction of two sewage treatment plants serving 99% of citizens. For “whenever an epidemic arises it awakens and shakes even the most slothful, instigating them to take prompt action: but unfortunate will be the individuals and countries who shut their ears to science and need a civilizing apostle such as for example cholera.”2
- Grosso E, Barbuti S, Leogrande G, Rizzo G. Prime Osservazioni sull’epidemia di Colera manifestatasi in Puglia nell’Agosto-Settembre 1973. Igiene Moderna 1974;5:1-8.
- Scavo B. Il colera in Bari e delle Puglie nel 1886. Bari, Italia: Stab. Tipografico Gissi e Avellino, 1887.
Italian Ministry of Health. Report to WHO on onset of Cholera cases in Italy, 1973 (modified).
|Region (N. of cases)||N. of cases||N. of deaths||Case fatality rate (%)|
* Milan (N. 2), Bologna (N. 1), Florence (N. 2), Rome (N. 3), Pescara (N. 1), all imported from the other three region involved.
SALVATORE BARBUTI, MD, Professor of Hygiene, has been the head of the Public Health Department at University of Bari Aldo Moro, Italy, for about forty years. He has authored numerous academic publications and several books such as the manual Igiene, medicina preventiva, sanità pubblica, used extensively in Italian Schools of Medicine. His effort and expertise during the cholera outbreak in 1973 remain milestones in Italian public health history.
DOMENICO MARTINELLI, MD, PhD is assistant professor of Hygiene, with 10 years of professional experience in infectious diseases and chronic diseases epidemiology, working as epidemiologist at the Public Health Department of University of Foggia, author of numerous academic publications.
ROSA PRATO, MD, is full professor of Hygiene and epidemiologist, with more than 25 years of professional experience in infectious diseases and chronic diseases epidemiology. She is the chief of the Public Health Department of University of Foggia, with long experience in coordination of granted research projects and academic publishing.
Winter 2017 | Sections | Infectious Diseases