Showing papers by "Joseph S. Bresee published in 2000"

Food-Related Illness and Death in the United States

Abstract: To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60,000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.

The epidemiology of enteric caliciviruses from humans: a reassessment using new diagnostics.

Abstract: In the United States, acute gastroenteritis is one of the most commonly noted illnesses on hospital discharge records and death certificates, yet few of these cases have an etiologic diagnosis. The application of new molecular diagnostic methods has shown caliciviruses (previously referred to as the Norwalk family of viruses or small round structured viruses) to be the most common cause of acute gastroenteritis (AGE) outbreaks in the United States, and they may emerge as a common cause of sporadic cases of AGE among both children and adults. Novel molecular methods have permitted outbreak strains to be traced back to their common source and have led to the first identification of virus in implicated vehicles of infection-water, shellfish, and foods contaminated both at their source and by food handlers. The broad application of these methods to routine diagnosis in hospitals and public health laboratories is advancing our appreciation of the full burden of calicivirus-associated diarrhea, and it is opening new avenues for its prevention and control.

Cold Weather Seasonality of Gastroenteritis Associated with Norwalk-like Viruses

Abstract: Norwalk-like viruses (NLVs) are the most common cause of acute nonbacterial gastroenteritis in adults, but little is known about their seasonality. The lack of specific diagnostic tools impeded study of these viruses in the past, and surveys using electron microscopy often grouped NLVs with other unrelated viruses. A search of the scientific literature found eight surveys of gastroenteritis, which were conducted for at least 1 year, that specifically identified NLVs. Unpublished data from laboratories of 4 NLV researchers were also used. These surveys, which were conducted in eight countries, reported sporadic cases and outbreaks of NLV-associated gastroenteritis among all age groups. The monthly occurrence of these cases and outbreaks was plotted, and while transmission occurred year-round in most surveys, a cold weather peak was demonstrated in 11 of the 12 studies. This key epidemiologic feature of the viruses has important implications concerning their mode of transmission and for understanding the etiology of acute gastroenteritis in adults.

Rotavirus vaccines and vaccination in Latin America

Abstract: Worldwide, rotaviruses account for more than 125 million cases of infantile gastroenteritis and nearly 1 million deaths per year, mainly in developing countries Rather than other control measures, vaccination is most likely to have a major impact on rotavirus disease incidence The peak incidence of rotavirus diarrhea occurs between 6 and 24 months of age In developing countries, however, cases are not uncommon among children younger than 6 months G serotypes 1 to 4 are responsible for most disease, but there are indications that in Brazil that G type 5 is of emerging epidemiological importance Both homotypic and heterotypic responses are elicited during natural rotavirus infection, and the immunological response at the intestinal mucosal surface is probably the more consistent predictor of clinical immunity With the primary objective of protecting children against life-threatening dehydrating diarrhea, many approaches to rotavirus vaccine development have been attempted One vaccine, the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV), was given licensing approval in the United States of America, introduced to the market, and later withdrawn A number of studies have found better efficacy of RRV-TV in developed countries than in developing ones Field trials with a 4 x 10(4) plaque-forming units (PFU) preparation of RRV-TV have been carried out in two countries in Latin America, Brazil and Peru Those trials yielded protective efficacy rates against all rotavirus diarrhea ranging from 18% to 35% Data from a large catchment trial in Venezuela with a higher RRV-TV dose, of 4 x 10(5) PFU/dose, indicated an efficacy rate of 48% against all rotavirus diarrhea and 88% against severe rotavirus diarrhea It appears that breast-feeding does not compromise the efficacy of RRV-TV if three doses of the vaccine are administered Similarly, possible interference of oral poliovirus vaccine with the "take" of the rotavirus vaccine can be overcome by giving three doses of the rotavirus vaccine or by using a higher-titer formulation of it Wild enteroviruses, however, may cause primary rotavirus vaccine failure in developing countries Studies in Peru with RRV-TV have shown a trend towards higher vaccine efficacy rates against "pure" (rotavirus-only) diarrheal episodes Economic analyses made in the United States indicate that a vaccine that costs less than US$ 9 per dose would lead to a net savings in medical costs To date, however, cost-benefit studies have not been done in developing countries In the future, it is possible that some Latin American countries might adapt their polio production facilities to the preparation of rotavirus vaccines for human use A year after RRV-TV was licensed for vaccination of infants in the United States, the occurrence of intussusception as an adverse event led to the vaccine's withdrawal from the market The implications of that action, particularly for Latin America, will be addressed in this article, including the need to explore alternative rotavirus candidate vaccines, particularly through the conduct of parallel clinical trials in both developed and developing countries

The Human Enteric Caliciviruses: an Expanded Role for Old Viruses

Abstract: The human enteric caliciviruses, previously known as the Norwalk family of viruses, the "classic human caliciviruses," or the small round-structured viruses, are a group of enteric pathogens that are a common cause of gastroenteritis in children and adults alike. When the gene encoding the capsid was expressed in baculovirus, the resulting protein self-assembled into virus-like particles that looked like natural virus by electron microscopy (EM) and provided replenishable reagents for serologic testing, structural studies, and antigen to develop immunoassays for antigen detection. These molecular discoveries and diagnostic advances have permitted researchers to reassess the clinical and epidemiologic features of illness caused by the caliciviruses and to reconsider public health approaches to their prevention and control. This chapter provides a review to highlight some of the advances in our understanding of calicivirus-associated gastroenteritis following the introduction of new molecular diagnostics, with illustrations drawn from several recent epidemic investigations. Tracing some epidemics back to their source has extended the use of diagnostics to the detection of viruses in contaminated food and water. Despite the major advances in the knowledge of the caliciviruses based upon the understanding of their sequence and molecular organization, the search for simple diagnostic assays has been difficult. Nonetheless, in the process of sequencing many strains, the human enteric caliciviruses fell into two distinct genera. The ability to sequence polymerase chain reaction (PCR) products made it possible to trace the molecular epidemiology of caliciviruses in outbreaks of disease.