Foodborne and Waterborne Illness: Prevention and Treatment
Prevention is the most effective way to limit the morbidity and mortality associated with food and waterborne illness. Essential to prevention efforts are clean drinking water, restaurant and meat inspection, temperature monitoring, appropriate sewage processing, monitoring of public waterways for contamination, and public education on proper hygiene. The public should be cautioned about foods presenting particular risk and given instruction in proper food handling and preparation.
Vaccines are available for hepatitis A and typhoid fever.
All patients with suspected foodborne illness should be instructed in proper hand–washing techniques to protect others with whom they are in contact. Diagnosis of foodborne illness generally requires notification of the department of public health.
Most acute diarrhea episodes are self–limited. Oral or intravenous rehydration therapy may be needed, and an antimotility drug (eg, loperamide) may be useful in viral diarrhea. Some outcomes may be improved or the disease course shortened through antibiotic treatment, but only when a specific diagnosis is suspected.
Salmonella (nontyphoidal) is usually self–limited, although antibiotic treatment should be used in very sick individuals, such as those with concurrent immunocompromised states or vascular disease or at the extremes of age.
Typhoid fever may be multidrug resistant. Fluoroquinolones or third–generation cephalosporins are generally effective, although resistance to many antibiotics has emerged.
Campylobacter may be treated with antibiotics, which may shorten the duration of illness. Typically, fluoroquinolones, erythromycin, and tetracycline are effective. However, many studies have verified growing resistance to fluoroquinolones.8
Shigella, like salmonella and campylobacter, is treated with antibiotics when patients are very sick, immunocompromised, or a risk to public health (ie, food handlers, day care attendees, hospital workers). Antibiotic choice depends on the age of the patient and resistance patterns. Typical antibiotics are trimethoprim–sulfamethoxazole, azithromycin, cephalosporins, and fluoroquinolones.
Cryptosporidiosis treatment is rarely necessary in immunocompetent persons.
E coli (O157:H7) should generally not be treated with antibiotics, as lack of efficacy is well–documented and treatment has been linked with a higher incidence of hemolytic uremic syndrome. Other E coli infections may require supportive therapy. Traveler’s diarrhea, often caused by E coli, usually responds to a fluoroquinolone given for 1 to 3 days.
Yersinia requires antibiotics in complicated illness only.
For Vibrio infections, rehydration therapy is essential due to the risk of severe diarrhea resulting in volume loss and shock. Antibiotics may shorten the course of diarrhea and vibrio excretion, and may be used as a therapy adjunct. Doxycycline, tetracycline, and fluoroquinolones are possible choices. Macrolides are commonly used for children.
Listeria should be treated promptly with intravenous antibiotics, such as penicillin G or trimethoprim–sulfamethoxazole. A 2–week treatment is generally prescribed, except in immunocompromised patients, for whom longer courses are required. Gentamicin can be added for severe infections, once its potential toxicity is considered.
Botulism may be treated with an antitoxin, and antibiotics may be used, although they have uncertain efficacy. Intense monitoring in a hospital is required. Other treatments (eg, wound debridement) may be considered if indicated.
Toxoplasma gondii infection should be treated in pregnant and immunocompromised patients, or in the presence of severe or prolonged symptoms. Pyrimethamine and sulfadiazine (folic acid antagonists) are the drugs of choice, along with folinic acid to prevent sulfadiazine–associated bone marrow suppression.
Cyclospora can be treated with trimethoprim and sulfamethoxazole.
Tapeworms can be prevented by cooking or freezing meat prior to ingestion and by avoiding cross–contamination. Praziquantel is the treatment of choice for active disease.
Amoeba and giardia may be treated with metronidazole.
Echinococcus calls for surgical excision (“marsupialization”) after cyst injection with hypertonic saline by surgeons familiar with this procedure. Oral albendazole may be provided as well.
Trichinosis can usually be prevented by freezing meat. For individuals who consume pork or other at–risk meats, thorough cooking also kills these pathogens. Treatment is not usually necessary, but mebendazole and albendazole are generally effective. Symptomatic treatment of pain and fever and systemic steroids are often helpful.
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