Typhoid Fever: Causes, Risks, and Prevention

• Food and waterborne diseases are transmitted by consuming contaminated food and water, usually by bacteria or viruses.

Typhoid Fever

• An acute illness associated with fever can be caused by Salmonella typhi bacteria.
• Salmonella paratyphi A, B, and C, are related bacteria that can also cause typhoid fever, though usually less severe.
• The bacteria multiply in the intestinal tract and can spread to the bloodstream.
• It is caused by Salmonella typhi, which thrives in poor sanitation and crowded conditions.
• Bacteria are deposited in water or food by a human carrier and then spread to others.
• Transmission may occur through direct contact with an infected person.
• Typhoid fever bacteria can be killed by heat at 60 degrees Celsius.
• The genus Salmonella belongs to Enterobacteriaceae.
• Salmonella is a facultative anaerobe.
• Salmonella are gram-negative bacilli.
• Salmonella is distinguished from other bacteria by biochemical and antigen structure.

Risk Factors for Typhoid Fever

• Children worldwide are at the greatest risk.
• Working or traveling in endemic areas.
• Close contact with someone infected or recently infected with typhoid fever.
• Having a weak immune system, such as from the use of corticosteroids or diseases like HIV/AIDS.
• Drinking water contaminated by sewage that contains S. typhi.

Mode of Transmission for Typhoid Fever

• Primarily through the fecal-oral route, with humans being the only reservoir.
• Via food handled by an individual who chronically sheds the bacteria in stool or, less commonly, urine.
• Hand-to-mouth transmission after using a contaminated toilet and not practicing proper hand hygiene.
• Oral transmission via sewage-contaminated water shellfish.
• Close contact with patients and carriers.
• Flies and cockroaches can also transmit the disease.

Pathophysiology of Typhoid Fever

• Ulceration in the Peyer's patches in the ileum can produce intestinal hemorrhage.
• Perforation can also occur in small number of cases.

Investigations for Typhoid fever

• Widal Test is an agglutination test that detects serum agglutinins (H - Flagellar and O – Somatic) in patient serum with typhoid and paratyphoid fever.

Typhoid Carriers

• Even after antibiotic treatment, some recoverees continue to harbor that bacteria in their intestinal tracts or gallbladders.
• Chronic carriers may shed the bacteria in their feces for years.
• Chronic carriers are still capable of infecting others, even without signs or symptoms.

Signs and Symptoms of Typhoid Fever

• Onset typically occurs one to three weeks after exposure.

Early Illness Symptoms

• Fever starts low and increases daily, potentially reaching 104.9°F (40.5°C).
• Headache.
• Weakness and fatigue.
• Muscle aches.
• Sweating.
• Dry cough.
• Loss of appetite and weight loss.
• Abdominal pain.
• Diarrhea with pea soup stool, or constipation.
• Rash of rose spots.
• Extremely swollen abdomen.
• After about 7-10 days, the patient looks toxic and exhausted.

Later Illness Symptoms

• Can become delirious if untreated.
• The patient may lie motionless and exhausted with eyes half-closed, a state known as the typhoid state.

Commonly Prescribed Antibiotics for Typhoid Fever

• Ciprofloxacin (Cipro) for nonpregnant adults.
• Ceftriaxone (Rocephin) is an injectable alternative for those who may not be candidates for ciprofloxacin, such as children.

Complications of Typhoid Fever

• Intestinal bleeding.
• Intestinal perforation.
• Septicemia.
• Myocarditis.
• Toxic hepatitis.
• Acute cholecystitis.
• Meningitis and toxic encephalopathy.
• Hemolytic uremic syndrome.

Prevention and Control of Typhoid Fever

• Notification to health authorities.
• Health education to the public and individuals.
• Sanitary disposal of human feces.
• Chlorination of public water supply.
• Controlling flies by spraying insecticides.
• Investigation of food and drink handlers.
• Personal hygiene of food handlers and food sanitation.
• Typhoid vaccination is recommended and/or mandated for food handlers.
• Vaccination is also recommended for travelers to areas where typhoid is common.
• It is also recommended for people in close contact with a typhoid carrier.
• It is recommended for laboratory workers who work with Salmonella Typhi bacteria.
• Vaccination is not 100% effective and is not a substitute for being careful about what you eat or drink.
• Inactivated (killed) injectable vaccine (lasts 2-3 years).
• Live attenuated (weakened) oral vaccine (lasts 5-7 years).
• Personal hygiene of individuals, e.g., hand washing after toilet use and before eating.
• Pasteurize milk before drinking.
• Investigate and treatment for positive cases and carriers.

Cholera

• It is an infection of the small intestine caused by the bacterium Vibrio cholerae.
• Cholera is usually found in food or water contaminated by feces from infected persons.
• The infectious agent is Vibrio cholerae.
• Vibrio cholerae is a Gram-negative, comma-shaped bacterium.

Mode of Transmission of Cholera

• Inadequate sewage treatment resulting in unsafe drinking water.
• Preparation of food/beverages with contaminated water.
• Unsafe domestic storage of freshwater.
• Washing fruits/vegetables with untreated water.
• Consumption of undercooked shellfish.
• Drinking contaminated water from a natural disaster such as flooding.
• Exposure to stool and vomit from cases and carriers.

Investigations for Cholera

• Gram stain from stool
• Stool culture and sensitivity
• Rectal swab

Signs and Symptoms of Cholera

• Sudden onset of vomiting and diarrhea.
• Stools that look like rice water.
• Severe thirst and muscle cramps.
• Rapid and feeble pulse.
• Low blood pressure.
• Reduced or stopped urine output due to dehydration resulting from diarrhea and vomiting.
• Can lead to severe shock and sudden death.

Treatment of Cholera

• Oral Rehydration Salt (ORS) or intravenous hydration is the mainstay.
• Antibiotic treatment is recommended for severely ill patients in conjunction to hydration.
• Doxycycline (Vibramycin) is recommended as first-line treatment for adults.
• Azithromycin is recommended as first-line treatment for children and pregnant women.

Prevention and Control of Cholera: Epidemic Measures

• Notification to health authorities is required when diagnosis is confirmed.
• Surveillance of all cases and carriers.
• Health education to the public regarding modes of transmission and prevention.
• Consume boiled water and cooked food.
• Investigations and treatment for food and drink handlers.
• Personal hygiene of food handlers and food sanitation.
• Vaccination as a cholera vaccine is a killed vaccine, but its protection is only 50-60%.
• Vaccination may not be the 1st choice during an outbreak because if false protection.
• Investigations of contacts and administer treatment if necessary.
• Proper excreta disposal.
• Food should be cooked, and water should be boiled before consumption.
• Wash hands before and after using the toilet.

Prevention and Control of Cholera: Hospital Management

• Specific antibiotic treatment with Vibramycin (Doxycycline).
• Fluid management.
• Use barrier nursing/isolation to prevent patients with an infectious disease from infecting others.
• Follow contact precaution procedures

Hepatitis A

• Transmitted through the fecal-oral route.
• Incubation: 2-6 weeks (average is 28-30 days).
• Nearly all fully recover and it does not lead to chronic disease.
• Period of communicability: latter half of the incubation period to a few days following onset of jaundice.
• The virus is spread when an uninfected person ingests food or water contaminated with feces of an infected person.
• Is closely associated with unsafe water, inadequate sanitation and poor personal hygiene.
• The Hepatitis A virus (HAV) is an RNA virus.
• HAV virion is a 27nm naked spherical particle.
• HAV can be found in blood and feces of infected humans and primates during the acute stage of infection.

Signs and Symptoms of Hepatitis A

• Range from mild to severe.
• Not everyone has all symptoms:
• Fever
• Malaise
• Loss of appetite
• Diarrhea
• Nausea
• Abdominal discomfort
• Dark-colored urine
• Jaundice

Investigations for Hepatitis A.

• Diagnosis can be made detecting specific IgM and IgG antibodies.

Treatment of Hepatitis A

• There is no specific treatment.
• Recovery from symptoms may be slow and take several weeks or months.
• Therapy aims at maintaining comfort and adequate nutritional balance, including replacement of fluids lost from vomiting and diarrhea.

Prevention of Hepatitis A

• Notification to health authorities.
• Proper sewage disposal within communities using closed systems.
• Ensuring adequate supplies of safe drinking water.
• Personal hygiene practices like regular handwashing with safe water.
• Immunization of contacts using IgG (Hepatitis A vaccine) for passive immunization.
• Investigations of contacts and treatment if necessary.
• Food hygiene and education for food handlers.