Symptoms
Infection with enterohemorrhagic EHEC manifests as mild, watery to severe, and bloody diarrhea (hemorrhagic colitis). Other possible symptoms include nausea, vomiting, colicky abdominal pain and mild fever. The disease can lead to life-threatening complications, in particular to the hemolytic uremic syndrome HUS. This manifests itself in acute kidney failure, a drop in blood platelets and anemia with dissolution of red blood cells. Dehydration, thrombotic thrombocytopenic purpura and central nervous system disorders are also possible. In many countries, between 35 to 69 cases per year have been reported in recent years. However, because of the nonspecific and sometimes mild symptoms and the ubiquitous occurrence in cattle, we believe the actual number of infections could be much higher. Smaller and larger local outbreaks are regularly reported worldwide. In Japan, for example, over 9,000 people became ill in 1996, partly due to contaminated radish sprouts. EHEC represents a global health problem that is ultimately attributable to livestock.
Causes
The cause of the disease is infection of the intestine with EHEC-type bacteria. These are gram-negative rod-shaped bacteria of the enterobacteria family. EHEC is a subgroup of the shiga-toxin-producing STEC. The best known serogroup is O157. The bacteria produce the cell-toxic and pro-inflammatory shigatoxins Stx1 and Stx2, which mediate both local and systemic toxic effects. They are also known as verotoxins, inhibit protein synthesis and lead to cell death. In addition, other bacterial factors play a role. In particular, attachment to intestinal cells is a key process in disease development.
Transfer
EHEC can be transmitted via food, water, direct contact with animals, or infected humans. The infectious dose required is low, ranging from 10 to 1000 bacteria. Shiga toxin-forming ones are found in the intestinal flora of many animals. However, cattle and other ruminants, which are the reservoir for the pathogen, are most significant for transmission to humans. Many animals carry toxin-producing strains. Although they excrete large amounts of the bacterium, they usually do not become ill because, among other things, they are less sensitive to the shiga toxins. EHEC is also found in wildlife, birds, pets, and insects. Water, soil, meat, fruits, and vegetables become contaminated with fecal material from the animals, and the bacteria can thus enter the human intestine directly or indirectly. Insufficiently cooked meat (e.g., ground beef, hamburgers, Mettwurst, salami, tartar), non-pasteurized dairy products (e.g., milk, yogurt, cheese), and vegetables (e.g., sprouts, lettuce, spinach) are important sources of infection. Finally, in a local outbreak, EHEC can also be transmitted fecal-orally from person to person through smear infections. Carriers may also be asymptomatic. The incubation period is 1-16 days.
Diagnosis
Diagnosis is made under medical care on the basis of the clinical picture and with laboratory chemistry methods (PCR, ELISA, culture, rapid tests). Possible differential diagnoses include numerous other diarrheal diseases.
Treatment
Treatment is based on symptoms and includes intravenous administration of fluids and electrolytes and, in severe cases, plasma exchange (blood washing). Antibiotics are not recommended because they are known to worsen the condition. Motility inhibitors such as loperamide (Imodium, generic) are also controversial and may promote complication rates. From our point of view, probiotics such as or probiotic could be an interesting therapeutic option. In severe cases of hemolytic uremic syndrome, experimental off-label treatment with the antibody and complement inhibitor eculizumab (Soliris) has been reported (e.g., Lapeyraque et al., 2011; Gruppo et al., 2009). However, there is no official regulatory approval for this indication.
Prevention
For personal prevention, there are a number of behavioral recommendations:
- Cook meat well, for example, minced meat. Each part of the meat must reach a temperature of 70 ° C or higher.
- Wash hands well with soap after contact with animals (eg, petting zoo, farm).Keep work clothes and shoes away from the living room and wash separately.
- Wash hands in general regularly well with soap.
- Store meat and meat products in the refrigerator.
- Do not consume non-pasteurized dairy products.
- Avoid contaminated foods.
- Wash or peel raw vegetables and fruits before consumption, observe hygiene in the kitchen.
Appropriate hygiene guidelines must be followed along the entire production chain from cultivation or growing to preparation in the kitchen to avoid contamination. Vaccines are not yet available.
