The outbreak of E. coli that Europe is currently experiencing is a different serotype than that associated with a chain of restaurants in the Pacific Northwest and West in 1993–“the outbreak that made E. coli famous” (my own quotable quote). Shortly before that, the Institute of Medicine had mentioned this bacterium as one of the emerging infections of public health importance. This serotype is O104:H4, which, like its more popular relative, is grouped under the heading “enterohemorrhagic E. coli” or EHEC. The bacterium produces a toxin which is similar to that produced by Shigella dysenteriae, and is referred to as Shiga-like toxin. In severe cases, hemolytic-uremic syndrome (HUS) may result. As a result of the toxin, hemolysis (destruction of red blood cells) may occur, ultimately resulting in kidney damage and renal failure. Supportive measures remain the mainstay of treatment, and since the 1993 outbreak, the consensus has been that antibiotics are counterproductive and may cause or increase the risk of HUS. Some recent evidence suggests that antibiotics such as imipenem or rifaximin may not increase the risk of HUS in the current outbreak, but this is the subject of current debate.
As of today (June 14, 2011), a total of 817 cases of HUS and 2508 non-HUS cases have been reported in the EU (see ProMED). The vast majority have been in Germany, particularly in the north, and epidemiologic investigation has demonstrated that a disproportionate number of cases report travel to northern Germany. Epidemiologic investigation has been complicated by the fact that multiple layers of multiple governments have been involved, and a report by BBC suggested that this has made coordination difficult even within Germany.
According to the National Center for Health Statistics, life expectancy in the US has reached an historic high, while mortality is now at an all time low. Mortality rates have decreased in each of the past 10 years. The age-adjusted mortality rate is now 741 per 100,000. The NCHS report notes that this represents a decrease of 30% since 1980.
Life expectancy at birth for females is 80.6 years, and for males it is 75.7 years. Notably, however, the existing gap between whites and blacks actually grew over the past year.
Cause-specific rankings have not changed, with coronary heart disease, cancers (all), chronic respiratory disease (COPD, which is chronic bronchitis and emphysema) and cerebrovascular disease (mostly stroke) heading up the list.
The causes of the decline have been debated. Undoubtedly, there is a combination of prevention, lifestyle changes, and more effective acute medical treatment that are among the explanations. But are there other explanations? And why does the US lag far behind other “developed” nations, and some middle income nations? Attention in the past decade has been devoted to income disparity and less “social capital” in the US–less feeling of social community. These explanations have been statistical and the links between social and pathophysiologic are yet to be established.
Up to 200 people attending a conference and fundraiser in Southern California have developed symptoms suggestive of Legionellosis (“Legionnaire’s Disease). Moreover, the bacterium, of the Legionella genus, has been isolated from a water source at the Playboy Mansion , where the fundraiser was held, providing a putative source of common exposure. Symptoms typically include fever, chills, nonproductive cough which can later become productive, lower respiratory involvement including pulmonary symptoms including pneumonia, and other non-specific findings. Specific identification is typically by antibody testing, a urine test in the case of the most common pathogen, L. pneumophila (only serotype 1) , and isolation and culture of the bacterium. The case fatality ratio can be highly variable, depending upon the species involved, the rapidity of recognition and rapid identification and treatment of patients, and perhaps the virulence of the specific organism. There are a number of effective antibiotics, including quinolones (eg levofloxacin), macrolides (eg azithromycin), and both are sometimes used with rifampin. In the originally identified outbreak in 1976, erythromycin was the antibiotic that was found to be efficacious–at the time, the fluoroquinolones had not yet been approved, and azithromycin had not been developed.
Posted in outbreaks
The other day after giving a lecture on emerging infectious diseases, I was thinking (again) about how the causes of disease emergence are mostly social. Actually, a former student, who is a retired biochemistry professor, suggested that I use the term “catalysts of emergence.” That was true in the original 1992 Institute of Medicine of Medicine report, and is true in the 2003 update by the IOM, “Microbial Threats to Health: Emergence, Detection, and Response” (National Academy Press) See nap.edu for online edition. The catalysts listed are 1) microbial adaptation and change; 2) human susceptibility to infection; 3) climate and weather; 3) changing ecosystems; 4) economic development and land use; 5) intent to harm; 6) technology and industry; 7) international travel and commerce; 8) breakdown of public health; 9) war and famine; and 10) lack of political will.
The argument is lengthy for a few of these catalysts, but each of these has social and biological factors underlying them. Yes, the catalysts are, in part, biological, but underlying the biology is behavior and society. Our task, in order to understand health and disease, is to understand the ties and intricate linkages at numerous scales between individual behavior, society, molecular structure, cellular processes, and microbial pathogenesis. It is very hard.
Cholera in New York City
Pro-MED reported today that a case of cholera has been diagnosed in New York City. This is not a major public health threat in itself, but it represents the first appearance of this severe infection in The City in decades, and could be a harbinger of what is to come. A reasonable hypothesis is that its appearance reflects travel patterns: the disease was transferred from Haiti’s island neighbor, the Dominican Republic. There is a great deal of travel between the DR and New York. Haiti is currently undergoing a major epidemic of cholera, largely because of the breakdown of public health measures following last year’s earthquake, and the concentration of thousands of displaced persons in refugee camps with only rudimentary sanitation facilities. Cholera can result in death within < 1 day in the most serious cases because of the electrolyte imbalances from uncontrolled diarrhea, and oral or IV rehydration, plus antibiotics (doxycycline or ciprofloxacin or similar drugs) are the only treatments. It all “boils” down to water.
Pro-MED is the “Program for Monitoring Emerging Diseases,” which is a “medium tech” listserve designed to report outbreaks to the global health community. It is sponsored by the International Society for Infectious Diseases, and can be found at promedmail.org. It represents the first attempt to include all interested subscribers in the “peoples’” surveillance system.
This is the first posting on this blog, which will have contents ranging from infectious and chronic disease epidemiology to clinical epidemiology and randomized clinical trials, spatial epidemiology, and health care policy, both in the USA, and globally.