Monday, June 22, 2015



Most people exposed to the cholera bacterium (Vibrio cholerae) don't become ill and never know they've been infected. Yet because they shed cholera bacteria in their stool for seven to 14 days, they can still infect others through contaminated water. Most symptomatic cases of cholera cause mild or moderate diarrhea that's often hard to distinguish from diarrhea caused by other problems.
Only about 1 in 10 infected people develops the typical signs and symptoms of cholera, usually within a few days of infection.
Symptoms of cholera infection may include:
  • Diarrhea. Cholera-related diarrhea comes on suddenly and may quickly cause dangerous fluid loss — as much as a quart (about 1 liter) an hour. Diarrhea due to cholera often has a pale, milky appearance that resembles water in which rice has been rinsed (rice-water stool).
  • Nausea and vomiting. Occurring especially in the early stages of cholera, vomiting may persist for hours at a time.
  • Dehydration. Dehydration can develop within hours after the onset of cholera symptoms. Depending on how many body fluids have been lost, dehydration can range from mild to severe. A loss of 10 percent or more of total body weight indicates severe dehydration.
    Signs and symptoms of cholera dehydration include irritability, lethargy, sunken eyes, a dry mouth, extreme thirst, dry and shriveled skin that's slow to bounce back when pinched into a fold, little or no urine output, low blood pressure, and an irregular heartbeat (arrhythmia).
Dehydration may lead to a rapid loss of minerals in your blood (electrolytes) that maintain the balance of fluids in your body. This is called an electrolyte imbalance.

Electrolyte imbalance

An electrolyte imbalance can lead to serious signs and symptoms such as:
  • Muscle cramps. These result from the rapid loss of salts such as sodium, chloride and potassium.
  • Shock. This is one of the most serious complications of dehydration. It occurs when low blood volume causes a drop in blood pressure and a drop in the amount of oxygen in your body. If untreated, severe hypovolemic shock can cause death in a matter of minutes.

Signs and symptoms of cholera in children

In general, children with cholera have the same signs and symptoms adults do, but they are particularly susceptible to low blood sugar (hypoglycemia) due to fluid loss, which may cause:
  • An altered state of consciousness
  • Seizures
  • Coma

When to see a doctor

The risk of cholera is slight in industrialized nations, and even in endemic areas you're not likely to become infected if you follow food safety recommendations. Still, sporadic cases of cholera occur throughout the world. If you develop severe diarrhea after visiting an area with active cholera, see your doctor.
If you have diarrhea, especially severe diarrhea, and think you may have been exposed to cholera, seek treatment right away. Severe dehydration is a medical emergency that requires immediate care regardless of the cause.

Antibiotic Treatment

Recommendations for the Use of Antibiotics for the Treatment of Cholera

Summary Recommendations

  1. Oral or intravenous hydration is the mainstay of cholera treatment.
  2. In conjunction with hydration, treatment with antibiotics is recommended for severely ill patients. It is particularly recommended for patients who are severely or moderately dehydrated and continue to pass a large volume of stool during rehydration treatment. Antibiotic treatment is also recommended for all patients who are hospitalized.
  3. Antibiotic choices should be informed by local antibiotic susceptibility patterns. In most countries, Doxycycline is recommended as first-line treatment for adults, while azithromycin is recommended as first-line treatment for children and pregnant women. During an epidemic or outbreak, antibiotic susceptibility should be monitored through regular testing of sample isolates from various geographic areas.
  4. None of the guidelines recommend antibiotics as prophylaxis for cholera prevention, and all emphasize that antibiotics should be used in conjunction with aggressive hydration.
  5. Education of health care workers, assurance of adequate supplies, and monitoring of practices are all important for appropriate dispensation of antibiotics.


  1. Mainstay of cholera treatment is hydration 
    Intravenous 1 and oral 2 hydration are both associated with greatly decreased mortality and remain the mainstay of treatment for cholera.
  2. Antibiotic effectiveness for the treatment of cholera
    • Antibiotics have been used as an adjunct to hydration treatment for cholera since 1964. Findings from randomized controlled trials evaluated the effectiveness of selected antibiotics on three main outcomes: stool output, duration of diarrhea, and bacterial shedding.These studies compared outcomes for cholera patients who were given both intravenous (IV) fluids and antibiotic treatment with those given IV fluids only. Findings indicate that antibiotics reduced volume of stool output by 8-92%, duration of diarrhea by 50-56%, and duration of positive bacterial culture by 26-83%3–7.
    • Antibiotic use for moderately and severely ill patients is also likely to reduce resource requirements. By decreasing duration of diarrhea and stool volume, antibiotics result in more rapid recovery and shorter lengths of inpatient stay, both of which contribute to optimizing resource utilization in an outbreak setting.
    • The majority of published studies exploring effectiveness of antibiotics for cholera patients have been done in patients who were adequately rehydrated. In these studies, there was no mortality and therefore the impact of antibiotics on mortality cannot be assessed. In the absence of adequate rehydration, antibiotics alone are not sufficient to prevent cholera mortality.
  3. Antibiotic regimens for the treatment of cholera 
    Tetracycline has been shown to be effective treatment for cholera 23 and is superior to furazolidone 8, cholamphenicol 9 and sulfaguanidine 9 in reducing cholera morbidity. Treatment with a single 300mg dose of doxycycline has shown to be equivalent to tetracycline treatment 10. Erythromycin is effective for cholera treatment, and appropriate for children and pregnant women 11. Orfloxacin 12, trimethoprim-sulfamethoxazole (TMP-SMX) 13, and ciprofloxacin 14 are effective, but doxycycline offers advantages related to ease of administration and comparable or superior effectiveness. Recently, azithromycin has been shown to be more effective than erythromycin and ciprofloxacin 1516 and is an appropriate first line regimen for children and pregnant women.
  4. Antibiotic resistance 
    Resistance to tetracycline and other antimicrobial agents among V. cholerae has been demonstrated in both endemic and epidemic cholera settings. Resistance can be acquired through the accumulation of selected mutations over time, or the acquisition of genetic elements such as plasmids, introns, or conjugative elements, which confer rapid spread of resistance. A likely risk factor for antimicrobial resistance is widespread use of antibiotics, including mass distribution for prophylaxis in asymptomatic individuals. Antibiotic resistance emerged in previous epidemics in the context of antibiotic prophylaxis for household contacts of cholera patients 1718.
  5. Unanswered questions 
    Inadequate information still exists with respect to antibiotics in the following areas:
    1. Effect of antibiotics on secondary transmission:
      • There are insufficient data examining the effect of antibiotics on secondary transmission of cholera. However, in published studies to date antibiotics have not been shown to decrease secondary transmission of cholera within households 1920.
    2. Utility of antibiotics when aggressive rehydration is not possible:
      • Because studies on antibiotic treatment for cholera were conducted in patients who received adequate rehydration, the effect of antibiotics in settings where this is not possible remains unclear.
  6. Summary of Antibiotic Treatment Guidelines
    Various organizations that participate in cholera responses recommend the use of antibiotics in cholera-infected patients with moderate or severe illness and who have begun IV hydration. None of the guidelines recommend antibiotics as prophylaxis for cholera prevention, and all emphasize that antibiotics should be used in conjunction with aggressive hydration. In addition, the guidelines recommend that antimicrobial susceptibility testing should inform local drug choices. Available guidelines are summarized below.
Guidelines for Cholera Treatment with Antibiotics
First-line drug choice
Alternate drug choices
Drug choices for special populations
World Health Organization 21Antibiotic treatment for cholera patients with severe dehydration onlyDoxycyclineTetracyclineErythromycin is recommended drug for children
Pan American Health Organization 22Antibiotic treatment for cholera patients with moderate or severe dehydrationDoxycyclineCiprofloxacin AzithromycinErythromycin or azithromycin recommended as first-line drugs for pregnant women and children Ciprofloxacin and doxycycline recommended as second-line drugs for children
International Centre for Diarrhoeal Disease Research, Bangladesh 23Antibiotic treatment for cholera patients with some or severe dehydration
Ciprofloxacin Azithromycin Cotrimoxazole
Erythromycin recommended as first-line drug for children and pregnant women
Medicins Sans Frontieres 24Antibiotic treatment for severely dehydrated patients onlyDoxycyclineErythromycin Cotrimoxazole Chloramphenicol Furazolidone
* Please note, due to space constraints, dosage information is not included in this table. Dosage guidance can be found by following the website links to the treatment guidance documents provided in the references section below 21-24.
  1. Considerations
    • Over-emphasizing antibiotics for treatment of cholera could divert resources from oral and intravenous rehydration.
    • Doxycycline costs approximately $0.02 per 100mg tablet. Azithromycin costs approximately $0.16 per 250mg tablet.
    • Antibiotics can cause nausea and vomiting. Gastrointestinal side effects should be carefully monitored, especially in dehydrated patients.
    • Antibiotics are not needed and should not be given to patients with cholera who have only mild or no diarrhea and dehydration.
    • Prospective surveillance for antibiotic resistance among bacterial isolates from any outbreak is essential for understanding and minimizing the spread of resistance.

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