Craig Dalton

An Outbreak of Gastroenteritis and Fever Due to Listeria monocytogenes in Milk

BACKGROUND After an outbreak of gastroenteritis and fever among persons who attended a picnic in Illinois, chocolate milk served at the picnic was found to be contaminated with Listeria monocytogenes. METHODS In investigating this outbreak, we interviewed the people who attended the picnic about what they ate and their symptoms. Surveillance for invasive listeriosis was initiated in the states that receive milk from the implicated dairy. Stool and milk samples were cultured for L. monocytogenes. Serum samples were tested for IgG antibody to listeriolysin O. RESULTS Forty-five persons had symptoms that met the case definition for illness due to L. monocytogenes, and cultures of stool from 11 persons yielded the organism. Illness in the week after the picnic was associated with the consumption of chocolate milk. The most common symptoms were diarrhea (present in 79 percent of the cases) and fever (72 percent). Four persons were hospitalized. The median incubation period for infection was 20 hours (range, 9 to 32), and persons who became ill had elevated levels of antibody to listeriolysin O. Isolates from stool specimens from patients who became ill after the picnic, from sterile sites in three additional patients identified by surveillance, from the implicated chocolate milk, and from a tank drain at the dairy were all serotype 1/2b and were indistinguishable on multilocus enzyme electrophoresis, ribotyping, and DNA macrorestriction analysis. CONCLUSIONS L. monocytogenes is a cause of gastroenteritis with fever, and sporadic cases of invasive listeriosis may be due to unrecognized outbreaks caused by contaminated food.

Characteristics of a widespread community cluster of H275Y oseltamivir-resistant A(H1N1)pdm09 influenza in Australia

Background. Oseltamivir resistance in A(H1N1)pdm09 influenza is rare, particularly in untreated community cases. Sustained community transmission has not previously been reported. Methods. Influenza specimens from the Asia–Pacific region were collected through sentinel surveillance, hospital, and general practitioner networks. Clinical and epidemiological information was collected on patients infected with oseltamivir-resistant viruses. Results. Twenty-nine (15%) of 191 A(H1N1)pdm09 viruses collected between May and September 2011 from Hunter New England (HNE), Australia, contained the H275Y neuraminidase substitution responsible for oseltamivir resistance. Only 1 patient had received oseltamivir before specimen collection. The resistant strains were genetically very closely related, suggesting the spread of a single variant. Ninety percent of cases lived within 50 kilometers. Three genetically similar oseltamivir-resistant variants were detected outside of HNE, including 1 strain from Perth, approximately 4000 kilometers away. Computational analysis predicted that neuraminidase substitutions V241I, N369K, and N386S in these viruses may offset the destabilizing effect of the H275Y substitution. Conclusions This cluster represents the first widespread community transmission of H275Y oseltamivir-resistant A(H1N1)pdm09 influenza. These cases and data on potential permissive mutations suggest that currently circulating A(H1N1)pdm09 viruses retain viral fitness in the presence of the H275Y mutation and that widespread emergence of oseltamivir-resistant strains may now be more likely.

A South Australian Salmonella Mbandaka outbreak investigation using a database to select controls

Between April and June 1996, 15 persons with Salmonella enterica serovar Mbandaka infection were reported in South Australia (population 1.6 million) compared with 12 over the previous five years. To identify a possible source for the infections a case control study was conducted.

Sesame seed products contaminated with Salmonella: three outbreaks associated with tahini.

In November 2002, the first of three outbreaks of Salmonella Montevideo infection in Australia and New Zealand was identified in New South Wales, Australia. Affected persons were interviewed, and epidemiologically linked retail outlets inspected. Imported tahini was rapidly identified as the source of infection. The contaminated tahini was recalled and international alerts posted. A second outbreak was identified in Australia in June-July 2003 and another in New Zealand in August 2003. In a total of 68 S. Montevideo infections, 66 cases were contacted. Fifty-four (82%) reported consumption of sesame seed-based foods. Laboratory analyses demonstrated closely related PFGE patterns in the S. Montevideo isolates from human cases and sesame-based foods imported from two countries. On the basis of our investigations sesame-based products were sampled in other jurisdictions and three products in Canada and one in the United Kingdom were positive for Salmonella spp., demonstrating the value of international alerts when food products have a wide distribution and a long shelf life. A review of the controls for Salmonella spp. during the production of sesame-based products is recommended.

Etiology of encephalitis in Australia, 1990-2007.

Unexplained disease etiology in hospitalized patients highlights the importance of surveillance to detect emerging novel pathogens.

Outbreaks of enterotoxigenic Escherichia coli infection in American adults: a clinical and epidemiologic profile.

Because enterotoxigenic Escherichia coli (ETEC) is not identified by routine stool culture methods, ETEC outbreaks may go unrecognized, and opportunities for treatment and prevention may be missed. To improve recognition of adult ETEC outbreaks, we compared them with reported outbreaks of viral gastroenteritis. During 1975-95, we identified 14 ETEC outbreaks in the United States and 7 on cruise ships, caused by 17 different serotypes and affecting 5683 persons. Median symptom prevalences were: diarrhoea 99%, abdominal cramps 82%, nausea 49%, fever 22%, vomiting 14%. The median incubation period was 42 h, and for 8 of 10 outbreaks, the mean or median duration of illness was > 72 h (range 24-264). For 17 (81%) ETEC outbreaks, but for only 2 (8%) viral outbreaks, the prevalence of diarrhoea was > or = 2.5 times the prevalence of vomiting. ETEC outbreaks may be differentiated from viral gastroenteritis outbreaks by a diarrhoea-to-vomiting prevalence ratio of > or = 2.5 and a longer duration of illness.

Foodborne Disease in Australia: The OzFoodNet Experience

In 2000, Australia improved national surveillance of gastrointestinal and foodborne illness by adapting the Centers for Disease Control and Prevention’s (CDC’s) FoodNet model of active surveillance. The OzFoodNet surveillance network applied concentrated effort at the national and local levels to investigate and understand foodborne disease, to describe more effectively its epidemiology, and to provide better evidence for minimizing the number of cases of foodborne illness in Australia. The Australian government funded each of Australia’s 6 states and 2 territories to employ 1 epidemiologist to enhance surveillance of foodborne disease, with a coordinating team based at the federal Department of Health and Ageing. OzFoodNet estimated that there are ∼5.4 million cases of foodborne disease per year, costing A

Discriminators between Hantavirus-Infected and -Uninfected Persons Enrolled in a Trial of Intravenous Ribavirin for Presumptive Hantavirus Pulmonary Syndrome

1.2 billion annually. In Australia, contaminated food results in ∼100 outbreaks of illness each year, with the incidence of outbreaks of illness caused by fresh produce and internationally distributed food increasing. In addition, OzFoodNet showed the value of aggregating national-level outbreak data for policy development and conducted successful multijurisdictional investigations of outbreaks; these investigations implicated a variety of foods, including alfalfa sprouts, chicken meat, eggs, peanuts, baby corn, tahini, and oysters. Foodborne diseases are globally important because of their high incidence and the costs that they impose on society. There is a great potential for large outbreaks of foodborne illness in both developing and developed countries. More than 200 different diseases may be transmitted through contaminated food or water [1]. Most foodborne diseases result in gastroenteritis, but other nongastroenteric illnesses are common. Prevention of foodborne disease occurs through interventions aimed at the

Syndromic surveillance: is it a useful tool for local outbreak detection?

To provide a potentially therapeutic intervention and to collect clinical and laboratory data during an outbreak of hantavirus pulmonary syndrome (HPS), 140 patients from the United States with suspected HPS were enrolled for investigational intravenous ribavirin treatment. HPS was subsequently laboratory confirmed in 30 persons and not confirmed in 105 persons with adequate specimens. Patients with HPS were significantly more likely than were hantavirus-negative patients to report myalgias from onset of symptoms through hospitalization, nausea at outpatient presentation, and diarrhea and nausea at the time of hospitalization; they were significantly less likely to report respiratory symptoms early in the illness. The groups did not differ with regard to time from the onset of illness to the point at which they sought care; time from onset, hospitalization, or enrollment to death was significantly shorter for patients with HPS. At the time of hospitalization, patients with HPS more commonly had myelocytes, metamyelocytes, or promyelocytes on a peripheral blood smear, and significantly more of them had thrombocytopenia, hemoconcentration, and hypocapnia. Patterns of clinical symptoms, the pace of clinical evolution, and specific clinical laboratory parameters discriminated between these 2 groups.

Online Flutracking survey of influenza-like illness during pandemic (H1N1) 2009, Australia.

New surveillance systems are required to meet the demands of a changing world. Traditional surveillance systems have served public health well in detecting and responding to infectious disease outbreaks. While generally passive and dependent on laboratory confirmation, they have provided sufficient information to identify disease clusters. The world we live in has changed extensively in the past few decades, with the threat of bioterrorism, an imminent influenza pandemic, massive population movement, and emerging infectious diseases requiring surveillance systems that provide adequate lead time for optimal public health response. Traditional surveillance systems often operate with considerable delay, thus complementary surveillance systems are required to provide the necessary lead time. Syndromic surveillance systems may fulfil this role.1,2 Syndromic surveillance uses clinical features that are discernable before diagnosis is confirmed or activities prompted by the onset of symptoms as an alert of changes in disease activity. Patient information may be acquired from multiple existing sources established for other purposes, including emergency department chief …