Cholera

Pathogen & transmission

  • Vibrio cholerae, gram negative bacteria

  • Ingestion of contaminated food or water

  • Incubation period: few hours to 5 days

  • Infection of small intestine

  • Cholera toxin, secretory diarrhoea

Clinical features

  • None to mild/severe watery diarrhoea/vomiting

  • Rice water stool (grey, slightly cloudy fluid that resembles water in which rice has been washed)

  • Dehydration, shock

Diagnosis

  • Dark field microscopy

Treatment

  • Hydration

  • Antibiotics (e.g. doxycycline, azithromycin) in severe cases, can shorten duration

Prevention

  • WASH, logistics

  • Vaccine

from ProMed:

As stated by Lutwick et al. (Lutwick LI, Preis J, Choi P: Cholera. In: Chronic illness and disability: the pediatric gastrointestinal tract. Edited by Greydanus DE, Atay O, Merrick J. New York: Nova Bioscience; 2017, pp 113-127), oral rehydration therapy can be lifesaving in outbreaks of cholera and other forms of diarrhea:

"As reviewed by Guerrant et al. (1), it was in 1831 that cholera treatment could be accomplished by intravenous replacement, and, although this therapy could produce dramatic improvements, not until 1960 was it first recognized that there was no true destruction of the intestinal mucosa, and gastrointestinal rehydration therapy could be effective, and the therapy could dramatically reduce the intravenous needs for rehydration. Indeed, that this rehydration could be just as effective given orally as through an orogastric tube (for example, refs 2 and 3) made it possible for oral rehydration therapy (ORT) to be used in rural remote areas and truly impact the morbidity and mortality of cholera. Indeed, Guerrant et al. (1) highlight the use of oral glucose-salt packets in war-torn Bangladeshi refugees, which reduced the mortality rate from 30% to 3.6% (4) and quote sources referring to ORT as "potentially the most important medical advance" of the 20th century. A variety of formulations of ORT exist, generally, glucose or rice powder based, which contain a variety of micronutrients, especially zinc (5).

"The assessment of the degree of volume loss in those with diarrhea to approximate volume and fluid losses can be found in ref 6 below. Those with severe hypovolemia should be initially rehydrated intravenously with a fluid bolus of normal saline or Ringer's lactate solution of 20-30 mL/kg followed by 100 mL/kg in the 1st 4 hours and 100 mL/kg over the next 18 hours with regular reassessment. Those with lesser degrees of hypovolemia can be rehydrated orally with a glucose or rice-derived formula with up to 4 liters in the 1st 4 hours, and those with no hypovolemia can be given ORT after each liquid stool with frequent reevaluation."

References:

1. Guerrant RL, Carneiro-Filho BA, Dillingham RA. Cholera, diarrhea, and oral rehydration therapy: triumph and indictment. Clin Infect Dis. 2003; 37(3): 398-405; http://cid.oxfordjournals.org/content/37/3/398.long.

2. Gregorio GV, Gonzales ML, Dans LF, et al. Polymer-based oral rehydration solution for treating acute watery diarrhoea. Cochrane Database Syst Rev. 2016; 12: CD006519; https://pubmed.ncbi.nlm.nih.gov/27959472/.

3. Gore SM, Fontaine O, Pierce NF. Impact of rice-based oral rehydration solution on stool output and duration of diarrhea: meta-analysis of 13 clinical trials. BMJ. 1992; 304(6822): 287-291; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1881081/.

4. Mahalanabis D, Choudhuri AB, Bagchi NG, et al. Oral fluid therapy of cholera among Bangladesh refugees. Johns Hopkins Med. 1973; 132(4): 197-205; https://jhu.pure.elsevier.com/en/publications/oral-fluid-therapy-of-cholera-among-bangladesh-refugees-5.

5. Atia AN, Buchman AL. Oral rehydration solutions in non-cholera diarrhea: a review. Am J Gastroenterol. 2009; 104(10): 2596-604; http://www.ncbi.nlm.nih.gov/pubmed/19550407.

6. WHO. The treatment of diarrhea, a manual for physicians and other senior health workers. 4th ed. 2005; http://whqlibdoc.who.int/publications/2005/9241593180.pdf.