Risk factors for hospitalisation and associated costs among patients with hepatitis A associated with imported pomegranate arils, United States, 2013.

OBJECTIVES: To assess hospitalisation risk factors and economic effects associated with a multistate hepatitis A outbreak in 2013. STUDY DESIGN: Retrospective case series. METHODS: Eligible outbreak-related cases confirmed by September 1, 2013, were defined as acute hepatitis symptoms and positive IgM anti-hepatitis A during March 15-August 12 among patients who consumed the food vehicle or had the outbreak genotype. We reviewed medical records, comparing demographic and clinical characteristics among hospitalized and non-hospitalized patients; we used logistic regression analysis to identify factors associated with hospitalization. We interviewed patients regarding symptom duration and healthcare usage and estimated per-patient and total costs. Health departments reported outbreak-related personnel hours. RESULTS: Medical records were reviewed for 147/159 (92%) eligible patients; median age was 48 (range: 1-84) years, and 64 (44%) patients were hospitalized. Having any chronic medical condition was independently associated with hospitalisation (odds ratio, 3.80; 95% confidence interval, 1.68-8.62). Interviews were completed for 114 (72%) eligible patients; estimated per-patient cost of healthcare and productivity loss was $13,467 for hospitalized and $2138 for non-hospitalized patients and $1,304,648 for all 165 outbreak-related cases. State and local public health personnel expenditures included 82 h and $3221/outbreak-related case. CONCLUSIONS: Hospitalisations in this outbreak were associated with chronic medical conditions and resulted in substantial healthcare usage and lost productivity. These data can be used to inform future evaluation of expansion of hepatitis A vaccination recommendations to include adults with chronic medical conditions.

Outbreak of hepatitis A in the USA associated with frozen pomegranate arils imported from Turkey: an epidemiological case study.

BACKGROUND: In May, 2013, an outbreak of symptomatic hepatitis A virus infections occurred in the USA. Federal, state, and local public health officials investigated the cause of the outbreak and instituted actions to control its spread. We investigated the source of the outbreak and assessed the public health measures used. METHODS: We interviewed patients, obtained their shopping information, and did genetic analysis of hepatitis A virus recovered from patients' serum and stool samples. We tested products for the virus and traced supply chains. FINDINGS: Of 165 patients identified from ten states, 69 (42%) were admitted to hospital, two developed fulminant hepatitis, and one needed a liver transplant; none died. Illness onset occurred from March 31 to Aug 12, 2013. The median age of patients was 47 years (IQR 35-58) and 91 (55%) were women. 153 patients (93%) reported consuming product B from retailer A. 40 patients (24%) had product B in their freezers, and 113 (68%) bought it according to data from retailer A. Hepatitis A virus genotype IB, uncommon in the Americas, was recovered from specimens from 117 people with hepatitis A virus illness. Pomegranate arils that were imported from Turkey--where genotype IB is common--were identified in product B. No hepatitis A virus was detected in product B. INTERPRETATION: Imported frozen pomegranate arils were identified as the vehicle early in the investigation by combining epidemiology--with data from several sources--genetic analysis of patient samples, and product tracing. Product B was removed from store shelves, the public were warned not to eat product B, product recalls took place, and postexposure prophylaxis with both hepatitis A virus vaccine and immunoglobulin was provided. Our findings show that modern public health actions can help rapidly detect and control hepatitis A virus illness caused by imported food. Our findings show that postexposure prophylaxis can successfully prevent hepatitis A illness when a specific product is identified. Imported food products combined with waning immunity in some adult populations might make this type of intervention necessary in the future. FUNDING: US Centers for Disease Control and Prevention, US Food and Drug Administration, and US state and local public health departments.

Human norovirus surrogate reduction in milk and juice blends by high pressure homogenization.

Novel processing technologies such as high pressure homogenization (HPH) for the inactivation of foodborne viruses in fluids that retain nutritional attributes are in high demand. The objectives of this research were (i) to determine the effects of HPH alone or with an emulsifier (lecithin) on human norovirus surrogates-murine norovirus (MNV-1) and feline calicivirus (FCV-F9)-in skim milk and orange juice, and (ii) to determine HPH effects on FCV-F9 and MNV-1 in orange and pomegranate juice blends. Experiments were conducted in duplicate at 0, 100, 200, 250, and 300 MPa for <2 s and plaque was assayed in duplicate. In milk, FCV-F9 was reduced by ≥4 and ∼1.3 log PFU/ml at 300 and 250 MPa, respectively, and ≥4- and ∼1-log PFU/ml reductions were obtained in orange juice at 300 and 250 MPa, respectively. In orange juice or milk combined with lecithin, FCV-F9 was reduced to nondetectable levels at 300 MPa, and by 1.77 and 0.78 log PFU/ml at 250 MPa. MNV-1 in milk was reduced by ∼1.3 log PFU/ml only at 300 MPa, and by ∼0.8 and ∼0.4 log PFU/ml in orange juice at 300 and 250 MPa, respectively. MNV-1 in milk or orange juice containing lecithin at 300 MPa showed 1.32- and 2.5-log PFU/ml reductions, respectively. In the pomegranate-orange juice blend, FCV-F9 was completely reduced, and MNV-1 was reduced by 1.04 and 1.78 log PFU/ml at 250 and 300 MPa, respectively. These results show that HPH has potential for commercial use to inactivate foodborne virus surrogates in juices.

Survival of human norovirus surrogates in milk, orange, and pomegranate juice, and juice blends at refrigeration (4 °C).

Fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis A virus outbreaks. The purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, MNV-1; feline calicivirus, FCV-F9; and bacteriophage MS2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °C). Juices, juice blends, and milk were inoculated with each virus over 21 days, serially diluted in cell culture media, and plaque assayed. MNV-1 showed no reduction in titer after 21 days in orange juice and milk, but moderate reduction (1.4 log) in pomegranate juice from a titer of 5 log(10) PFU/ml. However, MNV-1 was completely reduced after 7 days in the orange and pomegranate juice blend. FCV-F9 from a titer of 6 log(10) PFU/ml was completely reduced after 14 days in orange as well as pomegranate juice and by ∼ 3 logs after 21 days in milk at 4 °C. Interestingly, FCV-F9 was completely reduced after 1 day in the orange and pomegranate juice blend at 4 °C. MS2 was reduced by ∼ 1.28 log after 21 days in orange juice from a titer of 6 log(10) PFU/ml, and <1 log after 21 days in milk or pomegranate juice, with juice blends showing minimal reduction (<1 log) after 21 days at 4 °C. These results show the survival pattern of noroviruses that aid in the transmission of foodborne viral outbreaks. The data obtained can be used in quantitative viral risk assessment studies and to develop improved measures to prevent virus survival towards controlling outbreaks.