Food poisoning in a boys' hostel: same-day vomiting in 42 boys
At 2 p.m. on a Sunday, the warden of a boys' hostel with 180 inmates calls the local health centre. Forty-two boys who ate lunch of rice, chicken curry and curd at 12 noon are now vomiting; 20 have watery stools; two are drowsy with sunken eyes and have passed no urine since morning. The cook had a septic finger covered with a cloth while cooking. The leftover chicken was kept in a closed steel vessel at room temperature from noon to 4 p.m. and was then served to 30 boys who had returned from a trip. The hostel has one hand-washing tap for the kitchen and the cook's wound was dressed at home with ash. There is no resident doctor, the nearest laboratory is 30 km away, and it is a public holiday.
1. Using the incubation period and the pattern of illness, which organisms would you suspect first and why? Does the second serving help you decide?
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Short incubation points to preformed toxin. Vomiting began by 2 p.m. after a noon meal - roughly 2 hours. Toxin-mediated illness, not bacterial invasion, fits that speed:
- Staphylococcus aureus - the cook's septic finger is the classic source; toxin is produced in the food and is not destroyed by reheating.
- Bacillus cereus - the emetic type is linked to cooked rice held at room temperature; also 1–6 hours.
- Salmonella or Clostridium perfringens would be 8–72 hours and typically cause fever and diarrhoea rather than explosive vomiting; cholera gives profuse rice-water stools with rapid dehydration, and can still be present in the two drowsy boys.
The second serving is useful. Those 30 boys ate the same chicken about 4 hours later. If they become ill within 1–3 hours of eating it, the toxin was already in the food - supporting preformed toxin. If their illness starts later with fever, an organism multiplying in the food is more likely. Either way, the second event tells you the food was the vehicle and the kitchen the source.
Reasoning: you cannot wait for the laboratory. The two drowsy, anuric boys are already a medical emergency, and the incubation pattern, not the culture result, drives your first decisions.
2. What specimens will you collect, when, and what will you do with them given the holiday and the distance?
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Collect before antibiotics, if possible - antibiotics reduce the yield of the pathogen and can make the outbreak uninvestigable.
Specimens
- Vomitus from an affected boy (sterile wide-mouth container).
- Stool or rectal swab from 3–5 cases, including the two severe cases.
- Leftover chicken, rice and curd, and the vessel; also any water used in the kitchen.
- Swab from the cook's finger wound, and a nasal swab if available, since staphylococcal carriers shed from the nose and skin.
Handling
- Label each with name, time and source; keep food and stool at 4 °C in a cold box (do not freeze).
- Keep the food vessel unwashed and covered - washing destroys the evidence.
- Telephone the district laboratory and the medical officer first so that someone receives the cold box; document the chain of custody.
Reasoning: a pathogen recovered from both the patient and the food is what proves the vehicle and stops the outbreak recurring. The nurse's discipline here is to preserve evidence while treating the patient - the two are not in competition.
3. List your immediate actions in order of priority, and justify the order.
Read the worked answer
1. Treat dehydration first. Two boys are drowsy, sunken-eyed and anuric - severe dehydration. Give oral rehydration solution by cup and spoon to those who can drink; arrange urgent referral with IV Ringer lactate for the two severe cases. Why first: in food poisoning, deaths come from dehydration and electrolyte loss, not from the organism; this is the only intervention that changes survival within hours.
2. Separate the sick and stop the source. Suspend kitchen use, stop serving the implicated food, keep the cook away from food handling until the wound is treated and reviewed. Why second: it prevents new cases among the remaining 138 boys.
3. Notify and document. Inform the medical officer and the health inspector; fill the outbreak register with onset times, food history and numbers affected.
4. Water, hands and hygiene. Provide soap and water at the kitchen tap, boil or chlorinate drinking water, and teach hand-washing after toilet and before food.
5. Health education and follow-up. Explain to the warden and cooks that room-temperature storage of cooked chicken and a covered septic wound are the two preventable faults; re-inspect in one week.
Reasoning: priorities run from saving the sick to stopping further cases to proving and preventing - not from laboratory curiosity to treatment.