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Question 1

Giardiasis

Answer 1

> Flagella parasite that lives in the duodenum and upper jejunum and sometimes in the bile ducts and gallbladder
High-carbohydrate foods, reduced stomach acid and achloridria, and low immunoglobulin levels increase parasite proliferation.
In humid environments, cysts may survive outside the human body for months.
Humans are the natural hosts of Giardiamblia, and very similar species of Giardia have been seen in different animals.
The parasite is transmitted through food and water contamination by sewage, flies or people working in the food sector and manually-orally.
Infection is more common in children, especially in the age group of 6-10 years, than adults.
A large number of cysts are excreted intermittently in the feces, but except in diarrheal feces, a relatively small number of trophozoites are excreted in the feces.
The cyst opens in the duodenum after being eaten by a new host without being affected by gastric juice.
In volunteers, regular feeding of 100 cysts or more experimentally leads to infection.
The incubation period of the disease varies from 6 to 15 days and infections usually last up to 41 days

Question 2

Giardia infection

Answer 2

> Giardia infection can last for years and the person becomes an asymptomatic carrier
A large number of trophozoites have been seen in aspirated material from the small intestine, in biopsies of symptomatic patients, and in the duodenum and proximal part of the jejunum attached to the intestinal mucosa.
Patients with giardiasis diarrhea may have fatty diarrhea, impaired carotene, folic acid, and vitamin B12 absorption.
Disaccharides and other mucosal enzymes may also be severely reduced, and Consumption of bile salts by Giardia may interfere with normal pancreatic lipase activity.

Question 3

difference between Giardia stools and bacterial diarrhea

Answer 3

> An important difference between Giardia stools and bacterial diarrhea is the absence of blood and the increase in polymorphonuclear white blood cells in the stool.
In most infected people, the symptoms eventually go away without treatment.
Even if the excretion of the cyst continues, the presence of the lgM and the lgG antibodies against the raw parasite antigens in the serum of infected people can be shown, but the presence of these antibodies does not necessarily affect the excretion of the cyst.
Secretory lgA antibodies are thought to play an important role in mucosal immunity

Question 4

Diagnosis

Answer 4

> Diagnosis is usually made by finding a cyst in the solid stool and trophozoite and a cyst in the diarrhea stool.
The well-defined appearance of Giardia lamblia in physiological serum and iodinated growths, as well as in stained growths, distinguishes it from other intestinal protozoa.
Testing the contents of the duodenum to see a troozoite shows a higher percentage of positive cases than a stool test.

Question 5

Treatment

Answer 5

> Quinacrine hydrochloride for 5-7 days
Metronidazole is as effective as quinacrine

Question 6

Salmonella
Epidemiology of Salmonella typhi

Answer 6

> It survives in muddy waters for up to a month and in ice for up to 3 months.
It is destroyed by heat of 60 to 100 degrees.
Sunlight quickly kills bacteria
Resistant to drought (up to two months).
The number of microorganisms required to cause disease is 10,000 bacilli.
It is more prevalent in autumn and summer, This epidemic is especially seen in communities such as barracks and schools

Question 7

Ways of transmitting typhoid fever

Answer 7

> It enters the gastrointestinal tract through the mouth and from there to other parts of the body, and passes out through the feces.
Stools and bile are infected during the onset of the disease. Occasionally there are bacilli in the urine and vomit of patients, Most people with typhoid during the recovery period are also considered to be the source of Microbes.
Direct transmission: Nurses and caregivers of patients become infected through their hands

Question 8

Indirect transmission:

Answer 8

> Water: the best source of pollution
Unhealthy ice used to be a disease transmission agent in Iran.
Contamination of milk, fresh cheese with contaminated water or contaminated hands
Vegetables irrigated with human fertilizer
Marine mollusks and oysters and shrimp
Housefly
Meat powder, eggs and other foodstuffs
Laboratory personnel involved in the cultivation of these microbes, infectious disease physicians

Question 9

Pathogenicity of typhoid fever

Answer 9

> Enter the body by eating and drinking
Connection and proliferation in intestinal epithelial cells
Transmission into the bloodstream through the lymphatic system
Reproduction in the reticuloendothelial system (liver, spleen, gallbladder, .. and intestine)
Excretion by feces

Question 10

Clinical signs of typhoid fever

Answer 10

> The disease begins slowly after the incubation period of 10-14 days.
Mild fever (this is a gradual fever and then persists), fatigue, dizziness, bruising, disturbed sleep, bitter mouth and constipation.
Gradually, these symptoms worsen.
Severe headache, forehead pain, back and neck pain and lethargy
Flatulence
Splenomegaly
The fever is low in the morning and rises at night until the fever reaches 41 degrees in 4 to 5 days, The pulse is slower than fever.

Question 11

symptoms

Answer 11

> Symptoms worsen in 5 to 8 days
Skin rash ( Rose spots ) on the skin of the abdomen and chest
Deep numbness and bruising, delirium and insomnia
Excessive thirst, dry lips and tongue, poor appetite
In severe typhoid, there is watery diarrhea
The fever is constantly at 40 degrees Celsius, morning and night are slightly different, less in the morning and more at night.
White blood cell count is normal or below normal

Question 12

Complications of typhoid

Answer 12

> Intestinal bleeding
Perforation of the intestines
Appendicitis
Inflammation of the gallbladder
Jaundice
Parotiditis
Other complications: heart failure, bone, respiratory, urinary, cutaneous, meningitis, pyelonephritis and joint swelling
Mortality 10-15% before using antibiotics and 1% after using antibiotics
3% Of recovered people retain bacteria in the gallbladder, bile ducts, and rarely the intestines and gastrointestinal tract (healthy carriers).
Re-infection may occur but is milder.
With antibodies, relapse may occur 2-3 weeks after recovery

Question 13

Laboratory diagnosis of typhoid fever

Answer 13

. Culture and isolation of bacilli from blood (positive in the first week), bone marrow, feces (positive in the second and third weeks), urine, duodenal secretions (diagnosis of carriers)
. Find specific antigen in serum or urine. Slide agglutination, Vidal test (second and third weeks) and antibody against Vi antigen (carrier diagnosis), EIA
. PCR is very sensitive but not specific

Question 14

Sources of Salmonellosis Infection

Answer 14

> Water: Stool contamination causes an epidemic
Milk and other dairy products (ice cream, cheese, etc.): fecal contamination, inadequate pasteurization, improper preparation
Shrimp, fish and oysters: through polluted water
Dried and frozen eggs: from contaminated chicken to contaminated during preparation
Poultry meat and meat products: Contamination with rodent and human feces
Pets: Turtles, dogs, cats
Animal products as animal feed: unsanitary preparation
Incomplete cooling, incomplete cooking, contaminated raw food
Contamination of food suppliers and utensils is the cause of transfer from raw food to cooked materials (lack of hand washing, knives, cutting boards, table surface)
Storage of food at inappropriate temperature: low cold
Salmonella survives in peanut butter and chocolate (at low humidity) for many years

Question 15

Vibrio cholerae and cholera

Answer 15

> Curved gram-negative bacilli in the form of “ , “
Has a fast motion, polar cilium
No spores
They do not tolerate acidic pH, but tolerate alkaline pH (8.5-9.5)
Deactivation at 55 ° C within 15 minutes
Sensitive to drought
Growth at temperatures between 42-16 degrees
Vibrio cholera (classical biotypes O1 and O139) is the cause of cholera in humans

Question 16

Cholera epidemiology

Answer 16

> Cholera is endemic in India and Southeast Asia.
The natural source of Vibrio cholera is aquatic environments that attach to algae and crustaceans. It multiplies in water and turns off in inappropriate conditions.
Ways of transmitting the disease:
* Water, (survives in water for more than 3 weeks)
* Food
*Insects
& Infection occurs in 1-5% of susceptible individuals exposed to the bacterium
& Transportation lasts more than 3-4 weeks
& In the warmer months, the number of bacteria in contaminated water and food increases.

Question 17

Common sources of cholera

Answer 17

> Drinking water:
& It can be contaminated at the source (by feces through a penetrating well) or while accumulating (by a hand contaminated with feces).
& Leafy vegetables that have been irrigated or washed with contaminated water and used without proper disinfection.
Contaminated food:
& Aquatic foods such as fish and oysters (Taken from contaminated water, raw or undercooked)
& The causative agent of cholera survives in water, humid environments, fruits, vegetables, oysters and meat
& It does not tolerate much drought and sunlight and is destroyed by boiling water
& Contaminated ice that may have been prepared from contaminated water or contaminated during distribution

Question 18

Clinical signs of cholera

Answer 18

> The incubation period of the disease is 1-4 days
About 75% of people who get Vibrio cholera infection have no symptoms at all.
Another 20% suffer from diarrhea that is indistinguishable from diarrhea of ​​other organisms.
In a small number (2 to 5%) of people with the infection, watery diarrhea, vomiting and dehydration occur.
Symptomatic cholera begins with massive watery diarrhea, without fever or abdominal cramps
Stools of patients and stools, the appearance of a clear liquid stained with white mucus, which is called “rice water” stools, and usually is odorless or slightly fishy odor.
Vomiting that can be severe
Painful cramps in the legs.
Cramp in the stomach or in the arms and legs
Decreased urine volume
In untreated patients, rapid dehydration, acidosis, vascular collapse, hypoglycemia in children, cardiac arrhythmia and renal failure
There is a risk of death in 25-60% of untreated people.

Question 19

Ways to prevent cholera

Answer 19

> Drug prevention:
& Prescribing the drug as a prophylaxis can cause drug resistance to Vibrio cholera.
& The risk of transmitting cholera varies from patient to family
& Optional administration to family members in close contact with the patient is recommended in cases where epidemiological studies show that the rate of attack by family members is more than 20%

> Vaccination:
Vaccine use: To control cholera epidemic is ineffective and not recommended
Available vaccines have only 50% protective effect for 3 to 6 months.
These vaccines do not prevent asymptomatic infections, Therefore, vaccination of travelers will not prevent from entering of cholera to the country
Vaccination of patients’s family has no role in prevention

Question 20

Cholera prevention measures

Answer 20

> Establish a care system, including stool sampling for all cases of severe diarrhea
Establish a rapid reporting system
Regular monitoring of safe drinking water, including consuming water and swimming pools
Careful monitoring of the health of the food consumed
Close monitoring of proper disposal of human waste and waste and control of insects
Public health education about personal health
Educate all health professionals at all levels about the ways of transmission and methods of prevention and how to treat patients with diarrhea, including cholera.
Provide all necessary tools and equipment to diagnose the disease
Providing the necessary drugs and equipment to diagnose the disease in accordance with national guidelines
Evaluate the patient in terms of determining the degree of dehydration
Compensate for patient dehydration

Question 21

Shigella and Shigellosis(Bacterial dysentery or bloody diarrhea)

Answer 21

> Cylindrical gram-negative bacilli, they are also seen as Coco Bacilli
There are four species (Shigella dysenteriae, Shigella flexneri, Shigella Boydii, and Shigella Sonnei)
Immobile
Contains O antigen (more than 40 serotypes)
Humans are the only important reservoir of disease.
Its natural reservoir is in the human intestine and primates

Question 22

Epidemiology of Shigellosis

Answer 22

> The most common and serious infection is caused by Shigella dysenteriae.
This bacteria is a major cause of epidemic or endemic dysentery with high mortality.
Shigella causes about 600,000 deaths worldwide each year.
Two-thirds of cases and most deaths from the disease occur in children under 10 years of age. The disease is uncommon in infants under 6 months.
There have been epidemics in kindergartens.
It is transmitted from human to human through fecal-oral.
The infectious dose of Shigella is very high )100 )

Question 23

Shigella relationship with food

Answer 23

> Sensitive to heat
It does not survive at pH less than 4.5
Shigella flexneri and Shigella Sonnei are able to survive in pasteurized milk at 25 ° C for more than 170 days
It survives more than 50 days in eggs, oysters and shrimp
It survives longer at a temperature of 0.5-20 degrees
Shigellosis is most often caused by contamination of raw or cooked foods during preparation and operation at home and in public places.) Carriers who prepare food are responsible for the disease )

Question 24

Clinical signs of shigellosis

Answer 24

> Incubation period: 1-2 days
Sudden abdominal pain
Fever
Watery diarrhea (due to Shiga toxin)
After a few days, the frequency of defecation increases
Stools with a watery consistency and often with mucus and blood (bloody diarrhea)
Intestinal movements with a feeling of pressure and force
Rectal spasms with lower abdominal pain
50% of cases recover spontaneously after 2-5 days

Question 25

Clinical signs of shigellosis
> In children and the elderly:

Answer 25

& Dehydration, acidosis and death (often by Shigella dysenteriae), seizures (in children) and HUS hemolytic uremic syndrome (in children)
& Mortality in hospitalized patients is over 20%
& During acute infection and when there is an infectious agent in the stool (usually within 4 weeks of illness) there is a possibility of transmission.
& Chronic carriers are rare, recurrence of the disease is seen in them
& Anti-Shigella antibodies do not prevent re-infection

Question 26

Treatment of shigellosis

Answer 26

> Correction of mild to moderate dehydration with oral solutions and severe dehydration with appropriate intravenous serums
Treatment with appropriate antibiotics will reduce the duration and severity of the disease and the duration of pathogen excretion
Cotrimoxazole, ciprofloxacin or ofloxacin ( in adults) and cotrimoxazole, ampicillin, nalidixic acid or ceftriaxone in the treatment of children
The use of drugs that reduce intestinal motility, such as loperamide, is contraindicated in children and is not recommended in adults. This drug increases the duration of the disease.

Question 27

Prevention of shigellosis

Answer 27

> Actions for the patient:
& In case of an epidemic, immediate reporting of the disease is required
& Isolation of patients
& People who deal with food and infected children in kindergarten, patients who are caring for children, are allowed to return to work or kindergarten after two negative samples of negative stool culture or rectal swap. These samples must be collected at intervals of more than 24 hours. The sample is prepared 48 hours after discontinuation of antibiotics.
& If the care and feeding of children by these patients is unavoidable, hand washing should be done carefully after defecation and before meals.
The patient’s family actions:
& Encourage mothers to breastfeed their babies
& Educate people to observe personal hygiene and environmental health
& Investigate contact cases and search for the primary source of the disease

Question 28

Environmental measures

Answer 28

> Research on the state of drinking water in terms of pollution and the amount of residual chlorine
Preparation and distribution of safe water and disinfection and storage of water in a hygienic way
Observe the necessary precautions in preparing and storing food
Sanitary disposal of human waste
Adequate supply of soap and water in places visible and accessible to clients of health centers
Research on food and milk consumed
Due to the possibility of transmission of Shigella dysentery through beetles and house insects, combating them is also effective in prevention.