Table 1.
World Health Organization case definition for DHF and DSS*
| Case definition for DHF |
| The following must be present: |
| Fever or history of acute fever lasting 2–7 days, occasionally biphasic |
| Haemorrhagic tendencies, evidenced by at least one of the following: |
| A positive tourniquet test |
| Petechiae, ecchymoses or purpura |
| Bleeding from the mucosa, gastrointestinal tract, injection sites or other locations |
| Haematemesis or melaena |
| Thrombocytopenia (100 000 cells mm−3 or less) |
| Evidence of plasma leakage because of increased vascular permeability, manifested by at least one of the following: |
| A rise in the haematocrit equal to or greater than 20% above average for age, sex and population |
| A drop in the haematocrit following volume replacement treatment equal to or greater than 20% of baseline |
| Signs of plasma leakage such as pleural effusion, ascites and hypoproteinaemia |
| Case definition for DSS |
| All the above four criteria for DHF must be present plus evidence of circulatory failure manifested by: |
| Rapid and weak pulse |
| Narrow pulse pressure [<20 mmHg (2·7 kPa)] |
| Or manifested by: |
| Hypotension for age |
| Cold, clammy skin and restlessness |