Gastrointestinal Infectious Diseases

GASTROINTESTINAL
MICROBIAL
DISEASES of
Group 5

CONTENTS
 Infectious
 Bacterial
 Fungal
 Viral
 Parasitic

The digestive system comprises the gastrointestinal tract and
accessory organs. The gastrointestinal tract consists of the oral cavity,
pharynx, esophagus, stomach, small intestine, and large intestine. The
accessory organs are the teeth, tongue, and glandular organs such as
salivary glands, liver, gallbladder, and pancreas.
• The digestive system functions to provide mechanical processing,
digestion, absorption of food, secretion of water, acids,
enzymes, buffer, salt, and excretion of
waste products.
GASTROINTESTINAL

INFECTIOUS
01
The GI tract consists
of a long tube with many expanded areas designed
for digestion of food, absorption of nutrients, and elimination
of undigested materials. Transient and resident microbes continuously
enter and leave the GI tract. Most of the microorganisms ingested
with food are destroyed in the stomach and duodenum by the low
pH (gastric contents have a pH of approximately 1.5) and are
inhibited from growing in the lower intestines by the resident
microflora (microbial antagonism). They are then flushed
from the colon during defecation, along with large
numbers of indigenous microbes. The
indigenous microflora of the GI tract.

Infectious Diseases
 Infectious diseases are those caused by infectious agents - viruses, bacteria,
parasite and fungi
 If the organism is invaded by protozoa and helminthsm this is called invasive
disease
 Infectious disease are determined not only by its building, chemical structures,
antigenic properties but also nature of its interaction with the microorganism.

1
2
3
4
Salmonella Enterica
Campylobacter jejuni
Shigella
Escherichia coli
Aeromonas hydrophila
Listeriosis
Mycobacterium Tuberculosis
Chlamydis trachomatis (LGV)
Candida
Histoplasma capsulatum
Pnuemocytosis
Cryptococcus neoformans
Aspergillus
Penicillium marneffei
Zygomycetes
 Human Immunodefociency Virus
Cytomegalovirus
Herpes simplex
Varicella zoster
HHV-8 & HHV-6(Human
Herpesvirus)
Adenovitus
Cryptosporidium
Giardia lambia
Microsporidium
Entamoeba histolytica
Leishmania
Strongloides
Cyclospora cayetanensis
Isospora belli
PARASITIC
VIRAL
FUNGAL
BACTERIAL
Epstein-Barr Virus
Enterovirus
Norovirus
Astrovirus
Rotavirus
Human Papiloma virus

Colitis
 Inflammation of the colon (the large
intestine).
 caused by a viral, parasitic or bacterial
infection.
 Salmonella and E. coli are common causes.
 Most people get it from eating or drinking
contaminated food or water. It's usually
temporary, but some people may need
antibiotics to treat certain infections.
The INFECTIOUS DIEASE of the GI Tract includes the following:

Diarrhea
 An abnormally frequent discharge of semi solid or fluid fecal matter. Some laboratory
workers define diarrheal specimens as “stool specimens that conform to the shape of the
container.”
 Viral gastroenteritis is a common cause of acute diarrhea.
 Bacterial infections. Several types of bacteria can enter your body through contaminated
food or water and cause diarrhea.
 Common bacteria that cause diarrhea include Campylobacter link, Escherichia coli link
(E. coli), Salmonella link, and Shigella link.
Dysentery
 Frequent watery stools, accompanied by abdominal pain, fever, and dehydration. The
stool specimens may contain blood or mucus.

Diarrhea
 Diarrhea is a symptom in a wide variety of
conditions and diseases. It can be caused
by certain foods or drugs, or it may be the
result of an infectious disease. If diarrhea
results from an infectious disease, the
pathogen may be a virus, a bacterium, a
protozoan, or a helminth. Dysentery may
also be caused by various pathogens,
including bacteria (e.g., Shigella spp.
cause bacillary dysentery) and protozoa
(e.g.,amebiasis and balantidiasis.

Enteritis
 Inflammation of the intestines, usually referring to the small intestine.
 Most often caused by eating or drinking things that are contaminated with bacteria or
viruses. The germs settle in the small intestine and cause inflammation and swelling.
 Enteritis may also be caused by: An autoimmune condition, such as Crohn disease.
Gastritis
 Inflammation of the mucosal lining of the stomach.
 The inflammation of gastritis is most often the result of infection with the same bacterium
that causes most stomach ulcers or the regular use of certain pain relievers.
Gastroenteritis
 Gastrointestinal infections are viral, bacterial or parasitic infections that cause gastroenteritis.
 Inflammation of the mucosal linings of the stomach and intestines.

Hepatitis
 Inflammation of the liver; usually the result of viral infection, but can be caused by
toxic agents.
 The pain that Hepatitis patients experience is usually in the gastrointestinal tract,
specifically the stomach.
 The discomfort can be very severe and may be accompanied by nausea and
vomiting.
 In addition to these these problems, Hepatitis C may cause varices or swollen
blood vessels in the esophagus and stomach.

Bacterial
02
Bacterial gastroenteritis is a digestive problem
caused by bacteria. Symptoms include nausea,
vomiting, fever, diarrhea, abdominal cramping,
and pain. In severe cases, you may become
dehydrated and have an
electrolyte imbalance.
What is bacterial gastrointestinal?

What causes gastrointestinal bacterial infection?
 Bacterial gastroenteritis
commonly results from
consuming food or water that
has become contaminated
with bacteria or their toxins. It
can cause a range of
symptoms, including diarrhea,
abdominal cramping, nausea,
and vomiting.

Here are six of the most common gastrointestinal problems
Gastroesophageal Reflux Disease (GERD)
 It makes a case that small intestine bacterial overgrowth
(SIBO) may be the real cause of GERD.
 GERD most often presents as heartburn, but uncontrolled
GERD can erode the lining of the esophagus and lead to
bleeding. The condition can also cause pain in the chest so
extreme that it is sometimes mistaken for a heart attack.
 Controlling GERD usually begins with simple lifestyle changes, including
avoiding food for at least two hours before bedtime.
 Over-the-counter remedies can also provide some short-term relief for
occasional heartburn, but for chronic or serious GERD, a prescription
medication or even surgery may be necessary.

CHRONIC DIARRHEA
 Diarrhea is tricky to treat because it can
have so many possible causes. It could
be a result of the body’s inability to absorb
foods as with celiac disease and foods
containing gluten or a disease or disorder,
like irritable bowel syndrome (IBS),
Crohn’s disease or ulcerative colitis.
 Infections often viral and even parasites
can also be to blame.

 Chronic constipation is typically defined as having
fewer than three bowel movements a week for
three weeks or longer. It may also be the case that
stools are hard and difficult to pass.
 Treating the condition can begin with over-the-
counter remedies, such as stool softeners and
fiber supplements. Adding more fluids to your
diet — namely, water — may help.
 If those fail to bring relief, a physician may
recommend some exercise to strengthen the
muscles that move the stool through the bowels.
CHRONIC CONSTIPATION

GASTROENTERITIS
 Gastroenteritis is caused by an infection either viral or bacterial in the gut. Bacterial
infections can be caused by E. coli or salmonella, while viral infections can include
rotavirus or that infamous scourge of cruise ships, norovirus. Parasites, too, can cause
gastroenteritis.
 The best advice is to drink plenty of fluid to avoid dehydration and try to make the best of
it.
 Use good hand hygiene to prevent spreading the infection and, if at all possible, ask
others not to use the same bathroom facilities until your symptoms stop and you have a
chance to sanitize the facilities.

GASTROENTERITIS
 Symptoms lasting more than a few
days require further observation,
which may include testing for
antibodies that could indicate an
allergy or signs of infection in the stool
that can help a physician prescribe the
most effective treatment.

ULCERS
 The bacteria or NSAIDs can damage the mucus that lines the inside of the
stomach, exposing the interior of the stomach to acid which irritates the tissue
and causes the peptic ulcer. Essentially a sore on the inside of the stomach,
these can be very difficult to resolve because of the constant exposure to
stomach acid.
 A physician can run tests to determine if the peptic ulcer is caused by an
infection (usually H. pylori) and prescribe antibiotics for treatment.
 A proton pump inhibitor to reduce the acid in the stomach is also often
prescribed. Untreated, ulcers can not only cause pain, but may bleed,
leading to anemia.

ULCERS

 Hemorrhoids tend to cause pain or itching around the anus. You
may notice a hard knot near the anus or even bright red blood in
the toilet bowl.
 You can try treating hemorrhoids at home. Over-the-counter
ointments and cold packs can shrink the inflamed tissue.
Soaking in plain, warm water can help make the tissue softer,
enabling it to heal.
HEMORRHOIDS

 If these don’t work, consult a
physician. He or she can
recommend additional treatment,
including rubber band ligation,
which uses rubber bands to
prohibit blood flow to the
hemorrhoid, and sclerotherapy, in
which a small needle is used to
inject medication into the vessels
and cause them to shrink.
HEMORRHOIDS

03 VIRAL
Viruses are pathogens that commonly infect
immunocompromised patients.Viral infections are illness
you get from tiny organism that use your cells to make
more copies of themselves (viruses). Viral infections
commonly cause respiratory and digestive illnesses,
but viruses can also infect most other parts
of our body.

Mumps
 Mumps is an acute viral infection of the
salivary glands; parotid glands (Parotitis)
 T h e m u m p s v i r u s b e l o n g s t o t h e
paramyxovirus family
• RNA virus
 Humans are the only source of the virus
 Symptoms include fever, headache, sore
throat, face pain and swelling of the
parotid glands
 Transmission is by direct contact or by
inhaled respiratory droplets
Cold sores
(fever blisters)
 Caused by herpes simplex virus Type
I (HSV-1)
• DNA virus
 HSV-1 exhibits a latent infection cycle
that is extremely widespread
because it is easily transmitted by
close physical contact with saliva or
the lesions
COMMON MICROBIAL DISEASES OF GASTROINTESTINAL TRACT
Viral Disease of the Upper GI Tract

Viral Disease of the Upper GI Tract
COLD SORE MUMPS

VIRAL GASTROENTERITIS
 Is an inflammation, swelling, and irritation of
the inside lining of your gastrointestinal tract.
 A virus causes this illness. “Stomach Flu”
 It can infect yout stomach, small intestine, and
large intestine.
 Viruses can be found in the vomit and the
diarrhea of infected people. It can live for a
long time outside the body. People who are
infected can spread the virus to objects they
touch, especially if they don’t wash their
hands.

Kinds of
VIRUSES that
cause
Gastrointestinal
Infections

ROTAVIRUS
 Rotavirus is a very contagious virus that causes
diarrhea. Before the development of a vaccine, most
children had been infected with the virus at least once
by age 5.
 Although rotavirus infections are unpleasant, you can
usually treat this infection at home with extra fluids to
prevent dehydration. Occasionally, severe dehydration requires
receiving fluids through a vein (intravenously) in the hospital.
 Good hygiene, such as washing your hands regularly, is
important. But vaccination is the best way to prevent
rotavirus infection.
KINDS OF VIRUSES OF GASTROINTESTINAL TRACT

 Noroviruses are very contagious.
 They are found in the stool (feces) or vomit of infected
people.
 From there, noroviruses are transferred to food, water, or
surfaces by the hands of infected people who have not
washed adequately after using the bathroom.
 Noroviruses are a group of
viruses (previously known as
Norwalk-like viruses) that
can cause gastroenteritis, an
inflammation of the stomach
and intestines.
 Norovirus is the leading
cause of foodborne illness
outbreaks in Minnesota.
NOROVIRUS

 These people might not have any symptoms, but
are still be able to spread the virus to others.
 Adenovirus serotypes 40 and 41 are the most
common cause (5–20%) of acute gastroenteritis in
young children [5–8].
 Adenovirus infections are
most contagious during the
first few days of symptoms.
Some people, especially
t h o s e w i t h w e a k e n e d
immune systems, can carry
the virus in their tonsils,
adenoids, or intestines for
weeks or longer.
ADENOVIRUS

Signs of dehydration:
 Decreased urine output
 Dark-colored urine
 Dry skin
 Thirst
 Dizziness
Common symptoms include:
 Nausea
 Vomiting
 Watery diarrhea
Other possible symptoms are:
 Headache
 Fever
 Chills
 Stomachache
What are the symptoms of viral gastroenteritis?
Symptoms of viral gastroenteritis usually begin about 1 to 2 days after the virus gets
into the body.
Signs of dehydration in young children:
 Dry diapers (from a lack of urination)
 Lack of tears
 Dry mouth
 Drowsiness
 Sunken fontanel (the soft spot on the top of
an infant’s head)

• Your healthcare provider will most likely
diagnose your condition based on your
history and symptoms. You will rarely
need testing. If your symptoms persist,
your healthcare provider may ask for a
stool sample to look for viruses, bacteria,
and parasites.
How is viral gastroenteritis diagnosed?

4. Avoid any food or
water with warnings
of contamination.
1. Wash hands for 20 seconds with soap and water after going to the bathroom, after
changing a diaper, and before touching any food.
2. Use alcohol-based sanitizers.
3. If someone in the house has gastroenteritis, wash all surfaces that might be
contaminated with a
bleach-based cleaner.
PREVENTION
Vaccines are available to protect children
from rotavirus. Healthcare providers give
shots to babies before age 6 months. You
and your children can help prevent viral
gastroenteritis by taking these steps:

Helpful home care tips include:
 Drink plenty of light fluids like water, ice chips, fruit juice, and broth. Keep in mind that
sports drinks are high in sugar and are not appropriate if you are extremely
dehydrated. In this case, you will need an oral rehydration solution.
 Avoid drinks that contain milk, caffeine, and alcohol.
 Once you feel hungry
again, start with mild,
easy to digest foods.
 Rehydrate children
with oral rehydration
solutions.
TREATMENT
Specific treatment is usually not needed. In
most cases, you simply need to drink plenty
of fluids and rest at home until the virus
leaves your system. In rare cases, you may
need treatment for severe dehydration, with
IV (intravenous) fluids.

04FUNGAL
Fungi are pathogens that commonly infect
immunocompromised patients. At present, the incidence of
these pathogens in disease causation is gradually increasing
as a result of increased use of immunosuppressive drugs,
chemotherapy, and transplantation as well as infections
with the human immunodeficiency virus. Fungal
infections can affect any organ, including
those of gastrointestinal tract.

Oral Thrush (Oral candidiasis)
 is a condition in which the fungus
Candida albicans accumulates on the
lining of your mouth. Candida is a
normal organism in your mouth, but
sometimes it can overgrow and cause
symptoms.

Intestinal candidiasis
 Intestinal Candidiasis (IC) refers to an
overgrowth of the Candida yeast genus
in the small and large intestines. Its
presence in the gut is normal, but it can
be overabundant in certain populations
like premature infants and the
immunocompromised. Probiotics and
antifungal drugs may prevent IC

SIFO
 Small intestinal fungal overgrowth (SIFO) is
characterized by the presence of excessive
number of fungal organisms in the small
intestine associated with gastrointestinal (GI)
symptoms.
 Candidiasis is known to cause GI symptoms
particularly in immunocompromised patients
or those receiving steroids or antibiotics

Gastric Mucormycosis
 is an opportunistic, life-threatening fungal infection
caused by fungi of the class Zygomycetes.
 The disease has traditionally been reported in
immunocompromised patients, premature infants,
diabetics, transplant recipients, prolonged use of
corticosteroids or in condition associated with
increased availability of serum iron such as
acidosis or deferoxamine administration.
 The infection is progressive and associated with a
high mortality unless treatment is initiated promptly.

Gastrointestinal aspergillosis
 Aspergillosis is an opportunistic infection
commonly seen in immunocompromised
patients.Patients with hematological malignancies,
postorgan transplantation, or those with comorbid
conditions are susceptible to the development of
invasive aspergillosis. Aspergillosis can involve
the gut, causing vascular thrombosis leading to
ischemia and necrosis of the gut wall, resulting in
perforation.

FUNGAL
Signs and symptoms
of gastrointestinal
fungal infections
diarrhea
vomiting
melena
hemorrhage
abdominal pain
and fever
and are often similar
regardless of the type
of fungus involved.

05 PARASITIC
According to the Nicklaus Children’s Hospital,
When the gastrointestinal tract, most often the
intestine, is infected by a parasite, this is often
referred to as gastrointestinal parasites. If not
treated some parasites may linger for many
years and cause long term problems.
What is Gastrointestinal Parasites?

TAPEWORMS
 A tapeworm is a parasite that can live and feed in human intestines. This is called a
tapeworm infection. A young and inactive form of the tapeworm is called a larval cyst.
It can stay alive in other parts of the body. This is called a larval cyst infection.
 The sizes are about 1 mm (0.04 inch) to more than 15 m (50 feet)
 Their lifespan, the left untreated, adult tapeworms can live in a host body for up to 30
years. Their length varies, but they can grow to be anywhere from 6 to 22 feet
 Morphology. This is the longest tapeworm in humans – 3-10 m in length. It has
>3,000 proglottids which are more broad than long. The scolex is shaped as two
almond leaves.
The common types of gastrointestinal parasites includes:

ROUNDWORMS
 Roundworms are a group of parasites that includes pinworms and ascariasis.
 Roundworms can live inside the small intestine for up to 2 years. The worms
are about as thick as a pencil. They can grow to be about 13 inches long.
 External morphology: A live roundworm is generally dull white in
colour. Itlooks tubular like the earthworm. In the body of roundworm,
we can see four longitudinal lines, one dorsal, one ventral and two
laterals in position. In length, the female roundworm can be up to
20-25 cm while the male is up to 15-20 cm.

TAPEWORMS
ROUNDWORMS

 Most parasitic protozoa in humans are less than 50 μm in
size. The smallest (mainly intracellular forms) are 1 to 10
μm long, but Balantidium coli may measure 150 μm.
Protozoa are unicellular eukaryotes. As in all eukaryotes,
the nucleus is enclosed in a membrane.
 Protozoans are single-celled eukaryotes.
 Protozoa are microscopic,
one-celled organisms that can
be free-living or parasitic in
nature. They are able to
multiply in humans, which
contributes to their survival
and also permits serious
infections to develop from just
a single organism.
PROTOZOA

Risk factors for gastrointestinal
parasites include:
 International travel
 Poor sanitation
 Living or visiting an area known to
have parasites
 Poor hygiene and Age
 Weakened immune system
 Exposure to
child and
institutional
care centers

The symptoms of
gastrointestinal parasites
Many gastrointestinal parasites can live in the
intestines for many years without causing any
symptoms. Some of the symptoms they may cause
include: diarrhea, nausea, vomiting, abdominal pain,
bloating, fatigue, weight loss and other symptoms.
People can get infected with intestinal parasites by
eating contaminated food or water or by coming in
contact with contaminated soil.

Gastrointestinal parasites care options?
Medications are typically
effective at eliminating
gastrointestinal parasites and
returning the patient to health.
PARASITIC DISEASE

REFERENCES
Lamps, L. W., Lai, K., & Milner, D. A. (2014). Fungal Infections of the Gastrointestinal Tract in the Immunocompromised Host.
Advances in Anatomic Pathology, 21(4), 217–227.
https://doi.org/10.1097/pap.0000000000000016
Oral thrush in adults. (n.d.). NHS Inform.
https://www.nhsinform.scot/illnesses-and-conditions/infections-and-poisoning/oral-thrush-in-
adults#:~:text=Oral%20thrush%20is%20a%20fungal,group%20of%20yeasts%20called%20Candida.
De Bernardis, F., Arancia, S., & Sandini, S. (2010). Animal Models of Mucosal Candida Infections. In Elsevier eBooks (pp. 329–352).
https://doi.org/10.1016/s0580-9517(10)37014-0
Seladi-Schulman, J., PhD. (2019, December 4). What Is SIFO and How Can It Affect Your Gut Health? Healthline.
https://www.healthline.com/health/sifo
Naqvi, H., Yousaf, M. H., Chaudhary, F. S., & Mills, L. (2020). Gastric Mucormycosis: An Infection of Fungal Invasion into the Gastric
Mucosa in Immunocompromised Patients. Case Reports in Gastrointestinal Medicine, 2020, 1–7.
https://doi.org/10.1155/2020/8876125
Yelika, S. B., Tumati, A., & Denoya, P. (2020). Intestinal Aspergillosis: Systematic Review on Patterns of Clinical Presentation and
Management. Surgical Infections, 22(3), 326–333.
https://doi.org/10.1089/sur.2020.157
Liao TH, Hamosh P, Hamosh M. Fat digestion by lingual lipase: mechanism of lipolysis in the stomach and upper small intestine.
Pediatr Res. 1984 May;18(5):402-9.
Vegas, Carolina-Sanchez, MD (2021). Nicklaus Children Hospital.
https://www.nicklauschildrens.org/conditions/gastrointestinal-parasites#:~:text=The%20common%20types%20of%20gastrointestinal,international%20travel

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