TYPHOID FEVER & CONTROL MEASURES

The term enteric fever or typhoid fever is a communicable disease, found only in man and includes both typhoid fever caused by S.Typhi and paratyphoid fever caused by S.Paratyphi A, B and C . It is an acute generalized infection of the reticulo endothelial system, intestinal lymphoid tissue, and the gall bladder.

EPIDEMIOLOGY

According to the World Health Organization, globally some 16 million cases occur annually resulting in more than 600,000 deaths. More than 62% of the global cases occur in Asia, of which, 7 million occur annually in South East Asia. Other countries with a high incidence include Central and South America, Africa and Papua New Guinea.

Salmonellae are gram – ve rods, Salmonella currently comprise 2000 serotypes Two groups a) Enteric fever group b) Food poisoning group The bacilli are killed at 55ºc in one hour or at 60ºc in 15 minutes. They are killed within 5 minutes by mercuric cholride or 5% phenol Boiling or chlorination of water and pasteurization of milk destroy the bacilli The proportion of typhoid to paratyphoid A is 10:1, Paratyphoid B is rare and paratyphoid C is very rare .

Age group : Typhoid fever may occur at any age but it is considered to be a disease mainly of children and young adults. In endemic areas, the highest attack rate occurs in children aged 8-13 years.

Gender and race : Typhoid fever cases are more commonly seen in males than in females. On the contrary, females have a special predilection to become chronic carriers. Occupation : Certain categories of persons handling the infective material and live cultures of S. typhi are at increased risk of acquiring infection. Socio-economic factors : It is a disease of poverty as it is often associated with inadequate sanitation facilities and unsafe water supplies.

Social factors : pollution of drinking water supplies, open air defecation, and urination, low standards of food and personal hygiene, and health ignorance.

Nutritional status :Malnutrition may enhance the susceptibility to typhoid fever by altering the intestinal flora or other host defences. Incubation period : Usually 8-14 days but it may be as short as 3 days or as long as 60 days depending upon the dose of the inoculums. Reservoir of infection : Man is the only known reservoir of infection - cases or carriers.

About 10% of un treated typhoid fever patients discharge bacilli for 3 months after onset of symptoms . Fewer persons infected with paratyphoid organisms may become permanent gallbladder carriers 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:- All seasons, usually in summer and autumn.

Susceptibility is general , ( but it increases in people with gastric achlorhydria). - Relative resistance(immunity) follows: Clinical or sub-clinical infection, active immunization. in endemic areas , typhoid fever is most common in preschool children and children 5-19.

Mode of transmission : The disease is transmitted by faeco - oral route or urine – oral routes – either directly through hands soiled with faeces or urine of cases or carriers or indirectly by ingestion of contaminated water, milk, food, or through flies. Contaminated ice, ice-creams, and milk products are a rich source of infection.

Carriers may be temporary or chronic. Temporary (convalescent or incubatory) carriers usually excrete bacilli up to 6-8 weeks. By the end of one year, 3-4 per cent of cases continue to excrete typhoid bacilli. Persons who excrete the bacilli for more than a year after a clinical attack are called chronic carriers.

First week: The disease classically presents with step-ladder fashion rise in temperature (40 - 41°C) over 4 to 5 days, accompanied by headache, vague abdominal pain, and constipation. Second week: Between the 7 th -10 th day of illness, mild hepato-splenomegally occurs in majority of patients. Relative bradycardia may occur and rose-spots may be seen. Third week: The patient will appear in the "typhoid state" which is a state of prolonged apathy, toxaemia, delirium, disorientation and/or coma. Diarrhoea will then become apparent. If left untreated by this time, there is a high risk (5-10%) of intestinal hemorrhage and perforation.

2-5% patients may become Gall-bladder carriers. Rare complications: Typhoid hepatitis,Empyema, Osteomyelitis, and Psychosis. 2-5% patients may become Gall-bladder carriers. Unapparent or mild illnesses occur, especially in endemic areas .60-90% of patient with typhoid fever do not receive medical attention or are treated as outpatients.

Rose spots

DIAGNOSIS

Typhoid should be considered in any patient with prolonged unexplained fever in endemic areas and in those with a history of recent travel to endemic area. Prolonged fever, rose spots, relative bradycardia and leucopenia make typhoid strongly suggestive. Widal test measures titers of serum agglutinins against somatic (O) and flagellar (H) antigens which usually begin to appear during the 2nd week. In the absence of recent immunization, a high titre of antibody to O antigen > 1:640 is suggestive but not specific.

Polymerase chain reaction (PCR) can be performed on peripheral mononuclear cells. The test is more sensitive than blood culture alone (92% compared with 50-70%) but requires significant technical expertise Blood cultures are positive in 70-80% of cases during the 1st week. Stool and urine cultures are usually positive (45-75%) during the 2nd-3rd week. Bone marrow aspirate cultures give the best confirmation (85-95%)

Management of typhoid fever: General: Supportive care includes Maintenance of adequate hydration. Antipyretics. Appropriate nutrition. Specific: Antimicrobial therapy is the mainstay treatment. Selection of antibiotic should be based on its efficacy, availability and cost. Chloramphenicol , Ampicillin ,Amoxicillin , Trimethoprim &Sulphamethoxazole ,Fluroquinolones In case of quinolone resistance – Azithromycin, 3rd generation cephalosporins (ceftriaxone)

Specific protection MEASURES FOR SUSCEPTIBLES a) immunoprophylaxis b)health education VACCINES Injectable Typhoid vaccine 2. The live oral vaccine

Control of Typhoid fever MEASURES DIRECTED TO RESERVOIR a) Case detection and treatment b) Isolation c)Disinfection of stools and urine d)Detection & treatment of carriers MEASURES AT ROUTES OF TRANSMISSION a) Water sanitation b) Food sanitation c) Excreta disposal d) Fly control

Control of pts. and contacts:- RLHA (report to local health authority) 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 )

Chloramphenicol is the most effective drug treatment for S Chloramphenicol is the most effective drug treatment for S. typhi, and symptoms begin to improve slightly after only 24-48 hours of receiving the medication. Another drug, ceftriaxone, has been used recently, and is also extremely effective, lowering fever fairly quickly. Carriers of S. typhi must be treated even when asymptomatic, as they are responsible for the majority of new cases of typhoid fever.

Eliminating the carrier state is actually a fairly difficult task, and requires treatment with one or even two different medications for four to six weeks. In the case of a carrier with gall stones, surgery may need to be performed to remove the gall bladder, because the S. typhi bacteria are often housed in the gall bladder, where they may survive despite antibiotic treatment.

Within the hospital setting, infected people are cared for in isolation. Proper hand hygiene is the most important way of preventing further spread in hospital. Stool samples are also taken from members of the patient's family to identify any 'healthy' carriers.

Epidemic measures : 1) search intensively for the case/ carrier who is the source of infection and for the vehicle( water and food)through which infection was transmitted. 2) selectively eliminate suspected contaminated food .Pasteurize or boil milk. 3) chlorinate suspected water supplies adequately under competent supervision. 4) use vaccine should be considered before or during an outbreak.

Disaster implications: With disruption of usual water supply and sewage disposal and of control of food and water transmission and large scale outbreaks of t.f may occur if there are active cases or carriers in a displaced population. Selective immunization of stabilized groups such as school children, prisoners or hospital personnel may be helpful.

Injectable Typhim -Vi This single-dose injectable typhoid vaccine, from the bacterial capsule of S. typhi strain of Ty21a. This vaccine is recommended for use in children over 2 years of age. Sub-cutaneous or intramuscular injection Efficacy : 64% -72%

Typhoral This is a live-attenuated-bacteria vaccine. The efficacy rate of the oral typhoid vaccine ranges from 50-80% Not recommended for use in children younger than 6 years of age. The course consists of one capsule orally, taken an hour before food with a glass of water or milk (1stday,3rd day &5th day) No antibiotic should be taken during this period Immunity starts 2-3 weeks after administration and lasts for 3 years A booster dose after 3 years

Indications for Vaccination Travelers going to endemic areas who will be staying for a prolonged period of time, Persons with intimate exposure to a documented S. typhi carrier 3. Microbiology laboratory technologists who work frequently with S. typhi 4.Immigrants 5. Military personnel

Paratyphoid fever A,B,C Caused by Salmonella paratyphoid A,B,C Paratyphoid fever A,B,C Caused by Salmonella paratyphoid A,B,C.respectively. in no way different from typhoid fever in epidemiology, pathogenesis, pathology,clinical manifestations, diagnosis, treatment and Prophylaxis

Paratyphoid A,B: incubation period 2~15days, in general, 8~10 days Paratyphoid A,B: incubation period 2~15days, in general, 8~10 days. milder in severity fewer in complications. Better in prognosis, relapse more common in Paratyphoid A. Treatment same as in typhoid fever.

Paratyphoid C: Always sudden onset. Rapid rise of temperature Paratyphoid C: Always sudden onset. Rapid rise of temperature. Presented in different forms-- Septicemia, Gastroenteritis and Enteric fever Complications--arthritis, abscess formation, cholecystitis, pulmonary complications are commonly seen. Intestinal hemorrhage and perforation not as common as in typhoid fever.

Shigellosis

Definition Acute infectious disease of intestine lead to Serious gastrointestinal illness caused by the Shigella bacteria (dysentery bacilli). Place of lesion: sigmoid & rectum Pathological feature: diffuse fibrious exudative inflammation Clinical manifestation: fever, abdominal pain, diarrhea, tenesmus , stool mixed with blood, mucus & pus. Even companied with marked toxicity and shock,toxic-encepholopthy.

Shigellosis Very easy to spread from one person to another. It is very serious in babies, older adults, and people who are not well

Etiology Causative organism: dysentery bacilli, genus shigella, gram-stain negative, short rod,non-motile.Discovered over 100 years ago by a Japanese scientist named Shiga Groups: 4 groups & 50 serotypes - S. Dysenteriae (type 1) -the most sever and most deadly epidemics in developing world - S. sonnei- (Group D) –the most mild, 2/3 of shigellosis in the United States. -S.Flexnerii- almost all the rest of epidemic group and easily turn to chronic - S. Boydii-tropical -

occurrence World wide, 600.000 death /year word wide ,two third of cases . Most of deaths are in children below 10 year. out break occur in *over crowding conditions and *poor hygiene such as institutes ,*mental hospital ,and its endemic in tropical countries. Endemic in tropical and temperate climates

Reservoir Human only

How is shigellosis spread? Shigella is shed in the stool of infected people and is most often spread: on hands that have not been washed after using the bathroom from touching others or by touching food or drinks that others will eat by practices that involve fecal-oral contact In countries with inadequate sewage disposal, flies can carry Shigella from feces to food The infective dose can be as low as10-100organism.

Incubation Period Incubation Period - 1-3 days( 7 d. in S. dysenteriae).

Period of communicability During acute infection, until the infectious organism no longer in the stool ,usually 4 week after illness , chronic carrier is rare, s.t persist for months or longer, appropriate antibiotic reduced it for days.

Number of bacteria toxicity immunity Invasiveness - attachment Pathogenesis Number of bacteria toxicity immunity Invasiveness - attachment - penetration - multiplication

Pathogenesis-common Bacteria intestine Penetrate mucus Normal bacteria flora Multiply in epithelia cell & proper lamina Prevent attaching endotoxin Inflammation vessel contraction Endogenous pyrogen fever Superficial mucosal invasion ,necrosis and ulcer Diarrhea mixed with blood & pus

Symptoms sudden stomach pain stomach cramps diarrhea fever vomiting The symptoms of Shigella infection are: sudden stomach pain stomach cramps diarrhea hospitalization Young children – high fever & seizures fever vomiting blood, pus, and mucus in the stool. Symptoms begin about one day to one week after a person becomes infected and can last up to one week. Some people may have no symptoms but can still spread the infection to others.

Are there long term consequences to a Shigella infection? Persons with diarrhea usually recover completely, although it may be several months before their bowel habits are entirely normal. About 2% of persons who are infected with one type of Shigella, Shigella flexneri, later develop pains in their joints, irritation of the eyes, and painful urination. This is called post-infectious arthritis. It can last for months or years, and can lead to chronic arthritis. Post-infectious arthritis is caused by a reaction to Shigella infection that happens only in people who are genetically predisposed to it. Once someone has had shigellosis, they are not likely to get infected with that specific type again for at least several years. However, they can still get infected with other types of Shigella.

diagnosis Stool culture

Laboratory Findings Blood picture: total WBC count increase, neutrophils increase Stool examination: direct microscopic exam.: WBC, RBC, pus cells stool culture: Sigmoidoscope: shallow ulcer,scar, polyps

Treatment Persons with mild infections usually recover quickly without antibiotic treatment. However, appropriate antibiotic treatment kills Shigella bacteria, and may shorten the illness by a few days. The antibiotics commonly used for treatment are ampicillin, trimethoprim/sulfamethoxazole, ceftriaxone (Rocephin*), or, among adults, ciprofloxacin.

Some Shigella bacteria have become resistant to antibiotics Some Shigella bacteria have become resistant to antibiotics. This means some antibiotics might not be effective for treatment. Using antibiotics to treat shigellosis can sometimes make the germs more resistant. Therefore, when many persons in a community are affected by shigellosis, antibiotics are sometimes used to treat only the most severe cases.

Antidiarrheal agents such as loperamide or diphenoxylate with atropine (Lomotil*) can make the illness worse and should be avoided.

Prevention after using the bathroom after changing diapers Washing hands with soap and running water is the most important way to prevent the spread of Shigella after using the bathroom after changing diapers after cleaning the toilet after handling soiled towels or linens before eating before preparing food People with diarrhea should not fix or serve food that will be eaten by others

Prevention in Day Care Setting Never send a child with Shigellosis to a day care center, especially if the child has diarrhea Use day care centers that do the following: staff wash their hands after changing each diaper staff clean the changing area after each child children must wash their hands often children must wash their hands after using the toilet ill children are cared for at home or in a separate room facility is clean and sanitary

Prevention Not swimming ill with diarrhea Not swallowing recreational water Practicing good hygiene when using the pool

Public Health Interventions All Health departments excluded children with diarrhea from day care Not allowed to return until diarrhea ceased All but one health department did not allow children to return until two stool cultures testing negative for Shigella had been

Some tips for preventing the spread of shigellosis: Wash hands with soap carefully and frequently, especially after going to the bathroom, after changing diapers, and before preparing foods or beverages. Dispose of soiled diapers properly Disinfect diaper changing areas after using them. Keep children with diarrhea out of child care settings. Supervise hand washing of toddlers and small children after they use the toilet. Do not prepare food for others while ill with diarrhea Avoid swallowing water from ponds, lakes, or untreated pools.