EPIDEMIOLOGY & CONTROL OF TYPHOID FEVER DR.AWATIF ALAM

IDENTIFICATION: (Enteric Fever) Systemic bacterial disease with insidious onset of sustained fever headache, malaise, anorexia relative bradycardia, Splenomegaly rose spots on trunk constipation (more commonly than diarrhoea)

involvement of lymphoid tissues. Many mild and atypical infections may occur, Ulceration of peyre’s patches in ileum can result in intestinal haemorrhage or perforation ( in about 1% of cases).

C.F.R. : “dropped from 10% to 1% with antibiotic therapy.” DIAGNOSIS: Typhoid bacilli can be isolated : - from blood, early in disease, - from urine &/ faeces after Ist week - Agglutination reaction after 2nd week.

Infectious Agent:- Salmonella Typhi – (the typhoid bacillus) distinguished types – phage typing (of value in epidemiological studies). Occurrence:- Worldwide. (multiple resistant strains in Asia and Middle East )

Reservoir:- Man ( as patients & or carriers*) Family contacts may be transient carriers. Faecal carriers are more common than urinary carriers, Long-term carriers frequently present with chronic typhoid cholecystitis. Urinary carriers are frequently seen in areas where schistosomiasis hematobium infections also occur.

Mode of Transmission: Food and water contamination: by faeces or urine of a patient or carrier. examples : - Shellfish ( taken from sewage contaminated beds ), - raw fruits, vegetables, - milk , - products contam. by hands (of carriers or missed cases), are imp. vehicle in many parts of world. Flies can infect foods: (in which organisms may multiply to achieve an infective dose).

Incubation period: 1-3 weeks (depends on size of infecting dose) Period of communicability: - as long as bacilli appear in excreta (usually from Ist wk. throughout convalescence), 2-5% of cases will become permanent carriers. Susceptibility and resistance:- - Susceptibility is general , ( but it increases in people with achlorhydria). - Relative resistance follows: Clinical or sub-clinical infection, active immunization. Attack rates in endemic areas decreases with age.

METHODS OF CONTROL : Preventive:- (as in cholera). Encourage brst. + feeding for infants. Instruct pts., conval., and carriers in personal hygiene. Educate general public and esp. food *”certificate”handlers in the need for personal cleanliness (including attendants of pts. Or children). Exclude infected persons from handling food. Imm. – not routinely recommended.

Control of pts. and contacts:- RLHA Isolation with enteric precautions. Concurrent disinfection (of faeces, urine and soiled articles). Investigation of contacts and source of infection. *- Specific Rx: chloramphenicol ( of choice for acute cases )

Food poisoning& FOOD INTOXICATION

I.d:- “Not an infection”, (Occur through consumptn Of contaminated food or water). I.d:- “Not an infection”, - it’s rather an intoxicatn., -of abrupt onset with severe nausea,cramps and vomiting. - prostration, (often accomp. by diarrhea*), - subnormal temperature, hypotension death – rare. duration of illness (commonly not > 1-2 days)

2. Toxic Agent: - Several enterotoxins of: staphylococcus aureus, “ stable at boiling temperature”. (staph. multiply in food and produce their toxins). It is the most common among all types of food poisoning.

3. I. P. :30 mins. – 7 hrs. , usually 2-4 hrs. bet 3.I.P.:30 mins. – 7 hrs., usually 2-4 hrs. bet. eating food and onset of symptoms Note:-Organisms can exit: - in nasal secretions, - on the skin, - under the nails of a cook. 4.Susceptibility: General, depending on exposure.

METHODS OF CONTROL Notification: – R L H A. Send remains of food (and vomit) for laboratory investigation. Health education, especially among food handlers. Proper refrigeration of food.

“Other types of Food Poisoning” A. Salmonellae food infection : -through ingestion of contaminated food with animal excreta e.g. rodents. Signs & Symptoms: - Fever, - Abdominal Pain - vomiting and diarrhea. I.P.:6-48 hrs. Prevention: - Sanitatn. - Health education.

B. Botulism: I.d.: Severe intoxicatn. resulting from ingestn. of toxin performed in contamin. food and not from toxin produced in the gut. Toxic Agent:- Clostridium botulinum toxins. Note: The illness is charact. by manifestatns. Related to the nervous syst. (esp. cranial ns.) e.g. ptosis, visual difficulty, dry mouth. Then such symptoms may be followed by flaccid paralysis. Vomiting and diarrh. may be present initially. Fever absent unless a complicating infectn. occur.

Note: The illness is charact. by manifestations related to: - the nervous system (esp. cranial ns.) e.g. - ptosis, - visual difficulty, - dry mouth. - may be followed by flaccid paralysis. - Vomiting and diarrhea ( may be present initially). * Fever absent (unless a complicating infection occur).

Methods of Control:- Occurrence: World wide Reservoir: Soil, intestinal tract of animals. I.P.:12-36 hrs. (after eating contam. food). Suspect.: General. Methods of Control:- - Ensure effective control of processing and preparation of commercially canned and preserved foods. - Educate housewives regarding proper canning procedures (e.g. proper time, pressure, temp. req. to destroy spores and the need for adequate refrig. of food). R L H A Investigate contacts and source of toxin.

The golden rules for prevention of food poisoning 1- Choose foods processed for safety. 2- Cook food thoroughly. 3- Eat cooked food immediately. 4- Store cooked food carefully. 5- Reheat cooked food thoroughly. Do any of you eat poisonous plants? (ask for show of hands). No one would intentionally eat a poisonous plant. Now, raise your hand if you eat apples, peaches, or apricots (show of hands). Believe it or not, all of these are poisonous plants. What part of them do you avoid eating? The pits or seeds. And does anyone know what poison is the seeds? Cyanide. If you grind up a lot of them, enough cyanide could be produced to cause illness. People have been poisoned by mistaking hemlock roots for turnips or carrots, mistaking lily bulbs for onions, by eating fruits like ackee before they’re ripe, or by not preparing food properly (pokeweed has to be boiled well before eating).

6- Avoid contact between cooked and raw food. 7- Wash hands repeatedly. using lots of friction W—warm A—and S—soapy 8- Keep all kitchen surfaces meticulously clean. Wash dishes and utensils after contact with raw meat or eggs.

9- protect foods from insects, rodents and other animals. 10- use safe water. Keep hot food hot and cold food cold.

The End