Cholera information

WHO case definition for suspected cholera: A case of cholera should be suspected when
  • in an area where the disease is not known to be present, a patient aged five years or more develops severe dehydration or dies from acute watery diarrhoea
  • in an area where there is an outbreak of cholera, a patient aged five years or more develops acute watery diarrhoea, with or without vomiting. MSF case definition for presumed cholera: Any patient developing a rapid onset of severe watery diarrhoea (usually with vomiting), resulting in severe dehydration. CASE MANAGEMENT Patients must be quickly rehydrated with oral rehydration salts (ORS) or Ringer's lactate, depending on the level of dehydration and conscious level. Recommendations on the proportion of patients that need intravenous treatment vary with the guidelines: the WHO states 80?0% of cholera can usually be adequately treated with ORS solution alone, and that 20% of the patients can be rehydrated by intravenous treatment. However experience has shown that this proportion is too low for refugee settings and that it can reach 75%, probably because the proportion of severe dehydration is higher. CHOLERA TREATMENT UNIT The decision to open such a unit should be taken early (eg when five new cases are being admitted daily). CHOLERA TREATMENT UNIT REQUIREMENTS The estimated number of daily patient admissions should be calculated on the basis of the expected attack rate (around 5% in camp situations), the size of the population, the expected duration of the outbreak (which should be estimated at one month to ensure optimal bed capacity), the average length of hospitalisation (three days) and the stage reached in the outbreak (there will be more patients at the beginning). For instance, in a camp population of 50,000 people:
  • 2,500 cases can be expected during the course of the outbreak (attack rate of 5%) In refugee camps, overcrowding, poor sanitation and inadequate water supplies combined with the disorganisation of services have considerably increased the risk of cholera epidemics. Although cholera is a major killer, it should be remembered that acute diarrhoea - due to other causes than cholera - kills far more than cholera in refugee settings. According to the WHO, a cholera outbreak should be suspected when
  • a patient older than five years develops severs dehydration or dies from acute watery diarrhoea, or
  • there is a sudden increase in the daily number of patients with acute watery diarrhoea, especially patients who pass 'rice water' stools typical of cholera. In refugee or displaced settlements, any adult death by dehydration is thus highly suspect. An outbreak is declared as soon as there is a single bacteriologically-confirmed case. In open situations, the attack rate mostly varies from 1-2%, while in refugee camps, around 5% of the population may be expected to develop clinical cholera. The rate has been even higher in some epidemics. Cholera is a disease that can rapidly kill if left untreated: up to 50% of patients may die in the absence of treatment. OUTBREAK PREPAREDNESS In most refugee or displaced populations, cholera is a significant health risk, and particularly high when populations come from, or pass through or settle in a cholera-infected area.