Emerging Disease Research: Listeriosis
Gregory Parham
Virginia Military Institute
Gregory Parham, Psychology Department, Virginia Military Institute
Correspondence concerning this study should be addressed to Gregory Parham, Department of Psychology, Virginia Military Institute, Lexington, VA 24450.
parhamga21@mail.vmi.edu
For the last paper of summer school, I will be doing my emerging diseases research paper on the disease Listeriosis. Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. Listeriosis is found in soil and water. Vegetables become containment from the soil and manure used as fertilizer. Animals would carry the bacteria without showing symptoms and would contaminate foods of animal origin like meats and dairy products. The infectious disease is more likely to sicken pregnant women and their newborn babies, as well as adults aged 65 or older, and people with weakened immune systems. Symptoms for listeriosis varies, but it can cause confusion, loss of balance, convulsions, fever and diarrhea. Symptoms for pregnant women include flu-like symptoms, such as being fatigued and muscle aches, miscarriages, premature delivery, or life life-threatening infection of the newborn baby. The incubation period for listeriosis is 7 to 70 days and the illness can last from days to weeks.
Listeriosis is described as a non-spore-forming, gram-positive bacillus that is able to be aerobic and anaerobic. The disease has the ability to grow best at a neutral to slightly alkaline pH and at very wide ranges of temperatures. Nobody could really figure out why and how food could become spoiled and rotten but once Louis Pasteur and Robert Koch discovered bacteria in the 1800s, people began to understand how it was possible that food could be spoiled because of illness. The year 1926 came and scientist Dr. Everitt Murray documented the isolation of Listeria monocytogenes. He first named it Bacterium monocytogenes, but it was renamed as Listeria monocytogenes to honor a doctor named Joseph Lister, doctor who emphasized the importance for surgeons to sterilize their instruments before operations in order to stop the spread of infection. Listeriosis affects 2.500 Americans annually.
According to Alterkruse, Cohen, and Swerdlow (1997), the epidemiology of foodborne diseases is rapidly changing as newly recognized pathogens emerge and well-recognized pathogens increase in prevalence. From the early 1980s, foodborne transmission was a huge source of human listeriosis due to miscarriages, meningitis, and sepsis in hosts. Case-fatality rates were as high as 40% were reported during outbreaks. Outbreaks included cole slaw, milk contaminated after pasteurization, pork tongue, and soft cheese. The U.S. Department of Agriculture and U.S. Food and Drug Administration established a zero-tolerance rule for Listeria monocytogenes in foods in 1989. There are many factors that contribute to the emergence of foodborne diseases such as: human demographics, human behavior, changes in industry and technology, changes in travel and commerce, and prevention and control. Human demographics are a growing in the U.S. as well as the immunocompromised population which puts listeriosis higher among people who are HIV-infected than those who aren’t infected with HIV. Behavioral changes lead to foodborne infections by decreasing opportunities for food safety instructions both at home and school. Health educators are emphasizing the prevention of health concerns over food safety. Due to the changes in industry and technology, the geographic distribution of products from large centralized food processors carry a risk for outbreaks higher and higher. International travel has increased during the 20thcentury and international tourists has reached 937 million plus worldwide. Travelers can become infected with foodborne pathogens unknown in their respective nation of residence. Once the diversity of food in marketplaces hit and increase, illnesses were associated with internationally distributed foods. The last factor that contributes to the emergence of listeriosis is prevention and control, which deals with avoiding high-risk foods. We have to make sure we are processing, practicing, and facilitate cleanness to food safety.
Written from Self, Conrad, and Stroika (2019), there was a multistate outbreak of listeriosis associated with packaged leafy green salads in the United States and Canada between 2015 and 2016. Nineteen cases were identified in the United States from July 5, 2015 to January 31, 2016. Of the 19 cases, 16 were interviewed and all reported salad consumption and nine of those 16 reported it coming from the same facility. Listeriosis is the third leading cause of death from foodborne illness in the U.S. and cause an estimated 1,500 infections, 1,400 hospitalizations, and 250 deaths each year. Listeria monocytogenes was recognized first as a foodborne pathogen after an outbreak in Canada during 1981 that was linked to cabbage in coleslaw. The outbreaks of listeriosis in the United States were related to ready to eat meats, dairy products, and fresh produce such as celery, caramel apples, and cantaloupe. The investigation in the United States consisted of interviewing all the patients using the Listeria Initiative questionnaire, which collected standard laboratory, demographic, and clinical information. The questionnaire consisted of questions on 44 foods considered to have higher risk for Listeria monocytogenes and then conducted case to case comparisons using the questionnaire data to identify common food exposures among the patients and generate different hypotheses about possible outbreaks. On December 9, 2015, they began doing open-ended interviews and asked about all the foods consumed and data was collected as part of the response to a public health emergency. In Canada, they initiated interviews by either the national Enhanced Listeriosis Surveillance Program questionnaire or listeriosis questionnaires to gather food exposures during the 4 weeks before onset illness. Once they figured out the leafy green salads were identified, a centralized interview approach was used to re-interview patients.
The results came back with 19 cases of listeriosis in 9 states: Connecticut (1), Indiana (1), Massachusetts (1), Michigan (4), Montana (2), New Jersey (1), New York (6), Ohio (1), and Pennsylvania (1). All 19 patients were hospitalized and the median age for the case-patients were 64 and 14 out of the 19 cases were females. One case featured a pregnant woman and it resulted in a preterm live birth. Five case-patients completed the supplemental interviews, 12 case-patients completed open-ended interviews, one patient refused to be re-interviewed but provided a dietary log. 13 out of 16 patients reported romaine lettuce and 10 out of 14 reported spinach. In documentation, Listeria species were persisting in food processing and manufacturing environments, and the span of clinical cases over a period of time suggested that the main source of contamination was likely the processing/manufacturing environment. Overall, the processing facility implemented corrective actions.
The diagnosis for the disease of listeriosis is usually when a bacterial culture grows Listeria monocytogenes from a body tissue or fluid, such as blood, spinal fluid, or the placenta. A bacterial culture is a test used to determine whether bacteria or fungi are infecting a wound. According to cdc.gov, bacterial cultures are typically collected from infected tissue or from bodily fluids. Antibiotics are the most common choice of treatment, usually ampicillin. The preventions for this disease are don’t drink unpasteurized milk, do not eat foods that have unpasteurized milk in them, wash your hands, knives, countertops, and cutting boards after handling and preparing uncooked food and rinse raw produce thoroughly under running tap water before eating. Dealing with certain kinds of foods such as heat hot dogs, cold cuts, and deli meats to an internal temperature of 165 degrees Fahrenheit or until steaming hot before eating and eat cut melon right away or refrigerate it. The people at higher risks for listeriosis should be aware that Hispanic-style cheese made from pasteurized milk, such as queso fresco, has caused Listeria infections, because they were contaminated during the cheese-making process. The last prevention for listeriosis is that we can receive more awareness, patient education about the disease and methods of sterilization, such as irradiation, which improves the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects.
Ultimately, listeriosis is a disease you want to be more aware of when dealing with foods. You want to make sure you keep your heads, utensils, food all clean and kept away in a nice, safe place. Listeriosis is a foodborne disease that contaminates food and fresh produce, but there has been many preventions and strategies to where we can stop this illness. Just stay clean and fresh and everything will be fine!
References
Altekruse SF, Cohen ML, Swerdlow DL. Emerging foodborne diseases. Emerg Infect Dis. 1997;3(3):285–293. doi:10.3201/eid0303.970304
“Listeria (Listeriosis) | Listeria | CDC.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, www.cdc.gov/listeria/index.html.
Self, J. L., Conrad, A., Stroika, S., Jackson, A., Whitlock, L., Jackson, K. A….Basler, C. (2019). Multistate Outbreak of Listeriosis Associated with Packaged Leafy Green Salads, United States and Canada, 2015–2016. Emerging Infectious Diseases, 25(8), 1461-1468. https://dx.doi.org/10.3201/eid2508.180761.