TYPHOID

GENERAL INFORMATION

Disease

Typhoid (enteric) fever and typhoid-related diseases are bacterial infections of the digestive tract, reticuloendothelial system, and gall bladder caused by Salmonella typhi and contracted by ingestion of contaminated food and water.

• Transmission is through the fecal-oral route.
• Humans are the sole reservoir hosts.
  • The bacteria is shed in feces, typically for as long as 6 weeks to 3 months after infection.
  • Some persons remain infectious as chronic carriers.
• .

Symptoms Incubation period is 1-3 weeks

Sustained fever as high as 39° to 40° C. Can go on for many weeks if not treated.

Weakness,  stomach pains, constipation followed by diarrhea- headache, or loss of appetite. In some cases, patients have a rash of flat, rose-colored spots.

Hepato-splenomegaly

Complication: Bowel perforation – bleeding- necrotizing cholecystitis- meningitis-nephritis- myocarditis Death occurs from DIC and CNS involvement

Lab:

WBC : leucopenia, neutropenia

Blood and bone marrow examination . Stool culture.

Widal test: serum agglutinating antibodies to  H or O antigen testing.

Treatment:
Three commonly prescribed antibiotics are ciprofloxacin, azithromycin ,                    IV ceftriaxone ,.

20% may die from complications of the infection

Occurrence of typhoid is worldwide.

• In highly industrialized countries, it occurs typically as sporadic cases; some countries are virtually free of typhoid.
• It is common in most of the developing world.
  • Prevalence is high in countries with warm climates and with less developed sanitary facilities for sewage disposal and water treatment.
  • Typhoid is endemic in developing countries in Africa (north and west), Asia, and Central and South America and is especially common in India and Peru.

It is usually a disease of school-age children; it is not as severe in children younger than 2 years.

Travelers should be advised that the most effective prevention of typhoid-related diseases, as with other diarrheal diseases, is careful selection of food, water, and beverages.

• Proper preparation of formula and food from safe water and foodstuffs should protect infants who are not breast-fed.

Vaccines

The 3 vaccines available

Injectable Typhim Vi^TM (Aventis Pasteur, formerly Pasteur Mérieux Connaught)

This single-dose injectable typhoid vaccine, polysaccharide (carbohydrate) extracted from the bacterial capsule of S. typhi strain Ty2.

• This vaccine is not recommended for use in children younger than 2 years of age.
• Field trials in Nepal and South Africa revealed a 55-74% efficacy rate for Typhim Vi^TM.

Injectable Typherix ® (Salmonella typhi Vi Capsular Polysaccharide Vaccine) is indicated for active immunization against typhoid fever in persons two years of age and older. 

Dosing schedule for Typherix :One dose 0.5ml (0.25mg) administered intramuscularly ensures protection for at least 3 years. The vaccine must be given at least 2 weeks prior to travel to endemic areas. 

Oral (Vivotif Berna^TM)

. This is a live-attenuated-bacteria vaccine manufactured from the Ty21a strain of
S. typhi.

Per CDC, the efficacy rate of the oral typhoid vaccine ranges from 50-80%, partly depending on the degree of subsequent exposure.

Not recommended for use in children younger than 6 years of age.

Indications for Vaccination

Consider immunization for the following:

• Travelers going to endemic areas who will be staying for a prolonged period of time, eating adventurously, or venturing off the usual tourist routes into small cities, villages and rural areas
• Persons with intimate exposure to a documented S. typhi carrier
• Microbiology laboratory technologists who work frequently with S. typhi

ADMINISTRATION: INJECTABLE TYPHOID VACCINE TYPHIM VI^TM (Aventis Pasteur)

. Pediatric (> 2 years)

Do not use for children younger than 2 years of age.

Dose/Route and Schedule

Same as for adults (below). May inject in deltoid or vastus lateralis.

Adult

Dose/Route

0.5 mL, intramuscular (deltoid).

Schedule

Primary: Single intramuscular injection at least 1 week prior to exposure.

Booster: Single intramuscular injection every 3 years under conditions of continued or repeated exposure.

Per ACIP, it is acceptable to use either oral Ty21a or injectable Typhim Vi^TM as a booster dose in persons previously immunized with injectable Typhoid USP.

ADMINISTRATION: ORAL TYPHOID VACCINE TY21A (Vivotif Berna^TM)

Pediatric (> 6 years)

Do not use for children younger than 6 years of age.

Dose/Route and Schedule

Same as for adults (below).

Adult

Oral dose should be completed at least 1 week prior to exposure.

Dose/Route

Capsules or oral solution, taken orally.

Schedule

Primary: Capsules = 4 doses . Oral solution = 3 doses

1 capsule taken 1 hour before a meal with cool/lukewarm liquid every other day on days 0, 2, 4, and 6.

1 oral sachet  taken 1 hour before a meal dissolved with cool/lukewarm liquid every other day on days 0, 2, 4

Do not take with milk or alcohol.

• Capsules and oral solution must be kept refrigerated.

Remain viable at temperatures of < 80ºF for up to 48 hours, but this is not encouraged.

• Must not be exposed to direct sunlight.

Booster: Repeat 4 or 3 dose series every 5 years under conditions of continued or repeated exposure.

SIDE EFFECTS .

Injectable Typhim Vi^TM

The most common adverse reactions are injection site pain, erythema, and induration, which almost always resolve within 48 hours of vaccination.

Occasional fever, flu-like episodes, headache, tremor, abdominal pains, vomiting, diarrhea, and cervical pains have been reported.

Oral

Nausea, abdominal pain and cramps, vomiting, fever, headache, and rash or urticaria may occur in some instances but are rare.

PRECAUTIONS AND CONTRAINDICATIONS

Anaphylactic reaction to a previous dose contraindicates further immunization with that particular vaccine.

Anaphylactic reaction to a vaccine constituent contraindicates the use of vaccines containing that substance.

Injectable Typhim Vi^TM

This vaccine should not be given to children younger than 2 years of age.

A history of severe local or systemic reactions following a previous dose is a contraindication.

Per manufacturer, before administration this product should be checked visually for particulate matter and/or discoloration. If either of these conditions exists, the vaccine should not be used.

Phenol (0.25%) is added as a preservative.

Oral

This vaccine should not be administered to children younger than 6 years of age.

This vaccine should not be given to patients with acute vomiting or diarrhea.

Oral vaccine may be given to persons with prior reaction to the injectable vaccine.

Sulfonamides or antibiotics should not be taken with oral vaccine; vaccination should be delayed at least 24 hours after last dose of medication

Mefloquine hydrochloride may inhibit effectiveness of oral vaccine; administration of prophylactic mefloquine should be separated from oral typhoid vaccine by 24 hours.

• Per package insert, chloroquine and mefloquine can be administered simultaneously with Ty21a vaccine.
• Per WHO, oral typhoid vaccine should be completed at least 3 days before the first dose of mefloquine.

Bleeding Disorders

Because Typhim Vi^TM is an IM injection it may pose a risk for persons with bleeding disorders (e.g., thrombocytopenia, hemophilia, or other coagulation disorders).

Compromised Immunity

Like other live-attenuated vaccines, oral typhoid vaccine should not be given to immunocompromised persons.

Per the manufacturer of Typhim Vi^TM (Aventis Pasteur), the vaccine's expected immune response could be hindered if administered to persons who are immunosuppressed or receiving immunosuppressive therapy.

Pregnancy and Lactation

Per CDC, consider injectable vaccine only if actual risks of disease and probable benefits of vaccine outweigh theoretical risks to fetus.

Oral vaccine

• NO . There is a theoretical concern about the effect of live bacteria on the fetus.

Dr Assad