The Centers for Disease Control and Prevention (CDC), along with several state public health authorities and the U.S. Food and Drug Administration (FDA) investigated a multi-state outbreak of hepatitis A that was ultimately linked to fresh blackberries from Fresh Thyme Farmers Markets and Woodman’s Markets in September 2019. As of February 2020, a total of 20 hepatitis A cases from seven states (Indiana, Michigan, Minnesota, Missouri, Nebraska, Pennsylvania, and Wisconsin) were included in this outbreak.

Cases reported illness between October 8 and November 15, 2019. Ages ranged from 14 to 73 years (median 50). Sixty percent of ill cases were female. Eleven cases of 19 for whom information was available, were hospitalized, and no deaths were reported.

Of all cases interviewed (20), 19 reported eating fresh blackberries, and at least 16 cases reported purchasing those blackberries from either Fresh Thyme Farmers Market or Woodman’s Market. Blackberries purchased between September 9 and 30 were implicated in this outbreak. These statistically significant results indicated that fresh blackberries were the likely source of this outbreak. The FDA completed a traceback investigation but could not identify a single source for these fresh blackberries.[1]

Hepatitis A outbreaks associated with fresh, frozen, and minimally processed produce, worldwide, from 1983 to 2016
Year # Cases Implicated food Location of cases Source of implicated food Suspected cause of contamination Reference
1983 24 Raspberries (frozen) Scotland Scotland Infected pickers or packers Reid et al., 1987[2]
1987 5 Raspberries (frozen) Scotland Tayside, Scotland Infected pickers Ramsay and Upton, 1989[3]
1988 202 Iceberg lettuce Kentucky Unknown, suspected to be from Mexico Believed to have occurred prior to distribution, since multiple restaurants involved Rosenblum et al., 1990[4]



Strawberries (frozen) Montana, Georgia California Suspect an infected picker at farm Sivapalasingam et al., 2004;[5] Niu et al., 1992[6]
1996 30 Salad ingredients Finland Imported salad ingredients Unknown Pebody et al., 1998[7]
1997 256 Strawberries (frozen) Michigan, Maine, Wisconsin, Arizona, Louisiana, Tennessee

Grown in Mexico,

processed and frozen at a single California facility a year before consumption

Inconclusive due to time between harvest and consumption, suspect barehanded contact with berries at harvesting, coupled with few latrines and handwashing facilities on site Hutin et al., 1999[8]
1998 43 Green onions Ohio One of two Mexican farms or a farm in California Believed to be contaminated before arrival at restaurant Dentinger et al., 2001[9]
2000 31 Green onions or tomatoes Kentucky, Florida

Green onions: California or Mexico

Tomatoes: Unknown

Unknown Wheeler et al., 2005[10]; Datta et al., 2001[11]; Fiore, 2004[12]
2002 81 Blueberries New Zealand New Zealand, one orchard Inadequate bathroom facilities in fields, workers had barehanded contact with product, polluted groundwater from nearby latrines a possibility Calder et al., 2003[13]
2003 601 Green onions


Tennessee, Georgia, North Carolina

Mexico, two farms Contaminated during or before packing at farm CDC, 2003[14]; Wheeler et al., 2005[15]
2009 562 Tomatoes (semidried) Australia Unknown; imported and domestic product involved Product suspected to be imported due to concurrent outbreaks elsewhere at the time, source of contamination unknown Donnan et al., 2012[16]
2009 13



Netherlands Unknown; imported product suspected Identical strain to the 2009 Australian outbreak Petrignani et al., 2010[17]
2010 59



France Likely Turkey, single batch of product Unable to determine when and where contamination occurred. Virus was slightly different from one in the 2009 Australian and Dutch outbreaks. Gallot et al., 2011[18]
2012 9 Pomegranate seeds (frozen) Canada Egypt Suspect product contamination before export. Some history of travel to endemic areas among workers at Canadian processing facility, but less likely as only one product was associated with illness. CDC 2013[19]; Swinkels et al., 2014[20]
2013 103

Strawberries (frozen)

Other frozen berries may have been involved

Denmark, Finland, Norway, Sweden Suspected Egypt and Morocco based on virus strain and import history Unknown, some cases matched the strain of the larger 2013 European outbreak (see below) Nordic Outbreak Investigation Team, 2013[21]
2013 1589 Berries (frozen) Italy (90% of cases), Austria, Bulgaria, Denmark, England, Finland, France, Germany, Ireland, the Netherlands, Norway, Poland, Sweden Multiple food items containing frozen mixed berries (cakes, smoothies); Bulgarian blackberries and Polish redcurrants were the most common ingredients in the implicated lots Unknown, no single source found. Some cases also related to travel to Italy. Severi et al., 2015[22]; EFSA 2014[23]; Chiapponi et al., 2014[24]; Rizzo et al., 2013[25]; Guzman-Herrador et al., 2014[26]; Fitzgerald et al., 2014[27]
2013 165 Pomegranate arils (frozen) Arizona, California, Colorado, Hawaii, New Hampshire, New Jersey, New Mexico, Nevada, Utah, Wisconsin Turkey Unknown Collier et al., 2014[28]; CDC 2013[29]
2016 143 Strawberries (frozen) Arkansas, California, Maryland, New York, North Carolina, Oregon, Virginia, West Virginia, Wisconsin Egypt Unknown CDC 2016[30]



[2] Reid, T., Robinson, H. (1987). Frozen raspberries and hepatitis A. Epidemiol Infect, 98: 109–112.

[3] Ramsay, C. N. and Upton, P. A. (1989). Hepatitis A and frozen raspberries. Lancet, 1: 43–44.

[4] Rosenblum, L. S., Mirkin, I. R., Allen, D. T., Safford, S., Hadler, S. C. (1990). A multifocal outbreak of hepatitis A traced to commercially distributed lettuce. American Journal of Public Health, 80(9): 1075-1079.

[5] Sivapalasingam, S., Friedman, C. R., Cohen, L., Taube, R. V. (2004). Fresh produce: a growing cause of outbreaks of foodborne illness in the United States, 1973 through 1997. J Food Prot, 67: 2342-2353.

[6] Niu, M. T., Polish, L. B., Robertson, B. H. (1992). Multistate outbreak of hepatitis A associated with frozen strawberries. J Infect Dis 166: 518-524.

[7] Pebody, R. G., Leino, T., Ruutu, P., Kinnunen, L., Davidkin, I., Nohynek, H., & Leinikki, P. (1998). Foodborne outbreaks of hepatitis A in a low endemic country: an emerging problem? Epidemiology and infection, 120(1): 55-59.

[8] Hutin, Y. J., Pool, V., Cramer, E. H., Nainan, O. V., Weth, J., Williams, I. T. et al. (1999). A multistate, foodborne outbreak of hepatitis A. New England Journal of Medicine, 340(8): 595-602.

[9] Dentinger, C. M., Bower, W. A., Nainan, O. V., Cotter, S. M., Myers, G., Dubusky, L. M., Fowler, S., Salehi, E. D. P., and Bell, B. P. (2001). An outbreak of hepatitis A associated with green onions. J Infect Dis, 183: 1273-1276.

[10] Wheeler, C., Vogt, T. M., Armstrong, G. L., Vaughan, G., Weltman, A., Nainan, O. V. et al. (2005). An outbreak of hepatitis A associated with green onions. New England Journal of Medicine, 353(9): 890-897.

[11] Datta, S. D., Traeger, M. S., & Nainan, O. V. (2001). Identification of a multi-state outbreak of hepatitis A associated with green onions using a novel molecular epidemiologic technique [abstract 896]. In Program and abstracts of the 39th Annual Meeting of the Infectious Diseases Society of America. Alexandra, VA: Infectious Diseases Society of America (Vol. 192).

[12] Fiore, A. E. (2004). Hepatitis A transmitted by food. Clinical Infectious Diseases, 38(5): 705-715.

[13] Calder, L. , Simmons, G., Thornley, G. (2003). An outbreak of hepatitis A associated with consumption of raw blueberries. Epidemiol Infect, 131: 745-751

[14] Centers for Disease Control and Prevention (CDC). (2003). Hepatitis A outbreak associated with green onions at a restaurant–Monaca, Pennsylvania, 2003. MMWR, 52(47): 1155-1157. Available at

[15] Wheeler, C., Vogt, T. M., Armstrong, G. L., Vaughan, G., Weltman, A., Nainan, O. V. et al. (2005). An outbreak of hepatitis A associated with green onions. New England Journal of Medicine, 353(9): 890-897.

[16] Donnan, E. J., Fielding, J. E., Gregory, J. E., et al. (2012). A multistate outbreak of hepatitis A associated with semidried tomatoes in Australia, 2009. Clin Infect Dis, 54: 775–781.

[17] Petrignani, M., Harms, M., Verhoef, L. (2010). Update: a food-borne outbreak of hepatitis A in The Netherlands related to semi-dried tomatoes in oil, January-February 2010. Euro Surveillance, 15(20): 19572.

[18] Gallot, C., Grout, L., Roque-Afonso, A., Couturier, E., Carrillo-Santisteve, P., Pouey, J. et al. (2011). Hepatitis A Associated with Semidried Tomatoes, France, 2010. Emerging Infectious Diseases, 17(3): 566-567.

[19] Centers for Disease Control and Prevention (CDC). (2013). Multistate outbreak of hepatitis A virus infections linked to pomegranate seeds from Turkey (Final Update). Available at:

[20] Swinkels, H. M., Kuo, M., Embree, G., Andonov, A., Henry, B., Buxton, J. A. (2014). Hepatitis A outbreak in British Columbia, Canada: the roles of established surveillance, consumer loyalty cards and collaboration, February to May 2012. Euro Surveillance, 19: 20792.

[21] Nordic Outbreak Investigation Team C (2013). Joint analysis by the Nordic countries of a hepatitis A outbreak, October 2012 to June 2013: frozen strawberries suspected. Euro Surveillance, 18(27): 20520.

[22] Severi, E., Verhoef, L., Thornton, L., Guzman-Herrador, B. R., Faber, M., Sundqvist, L. et al. (2015). Large and prolonged food-borne multistate hepatitis A outbreak in Europe associated with consumption of frozen berries, 2013 to 2014. Euro Surveillance, 20(29): 1-9.

[23] European Food Safety Authority (EFSA). (2014). Tracing of food items in connection to a multinational hepatitis A virus outbreak in Europe. EFSA Journal, 12(9): 3821-4007. Available at http://

[24] Chiapponi, C., Pavoni, E., Bertasi, B., Baioni, L., Scaltriti, E., Chiesa, E., et al. (2014). Isolation and genomic sequence of hepatitis A virus from mixed frozen berries in Italy. Food Environ Virol, 6(3): 202-206.

[25] Rizzo, C., Alfonsi, V., Bruni, R., Busani, L., Ciccaglione, A., De Medici, D., et al. (2013). Ongoing outbreak of hepatitis A in Italy: preliminary report as of 31 May 2013. Euro Surveillance, 18(27): 20518.

[26] Guzman-Herrador, B., Jensvoll, L., Einoder-Moreno, M.,
Lange, H., Myking, S., Nygard, K., et al. (2014). Ongoing hepatitis A outbreak in Europe 2013 to 2014: imported berry mix cake suspected to be the source of infection in Norway. Euro Surveillance, 19(15): 20775.

[27] Fitzgerald, M., Thornton, L., O’Gorman, J., O Connor, L., Garvey, P., Boland, M., et al. (2014). Outbreak of hepatitis A infection associated with the consumption of frozen berries, Ireland, 2013 – linked to an international outbreak. Euro Surveillance: European communicable disease bulletin, 19(43).

[28] Collier, M. G., Khudyakov, Y. E., Selvage, D., Adams-Cameron, M., Chiepson, E., Cronquist, A., et al. (2014). Outbreak of hepatitis A in the USA associated with frozen pomegranate arils imported from Turkey: an epidemiological case study. Lancet Infectious Diseases, 14(10): 976-981.

[29] Centers for Disease Control and Prevention (CDC). (2013) – Multistate outbreak of hepatitis A virus infections linked to pomegranate seeds from Turkey (Final Update), supra note 85.

[30] Centers for Disease Control and Prevention (CDC). (2016). 2016 – Multistate outbreak of hepatitis A linked to frozen strawberries (Final Update). Available at