Structure
11.1 Introduction
11.2 Diarrhoea
11.2.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.2.2 Symptoms and complications of dianhoea
11.2.3 Control. prevention and management of diarrhoea
t 11.3 Dysentery
i 11.3.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.3.2 Symptoms and complications of dysentery
11.3.3 Control. prevention and management of dysentery
I 11.4 Cholera
11.4.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.4.2 Symptoms and complications of cholera
11.4.3 Management. control and prevention of cholera
11.5 Let Us Sum Up
11.6 Glossary
11.7 Answers to Check Your Progress Exercises
Diarrhoea, dysentery and cholera are the major cause of sickness and death mostly
amongst children. in almost all the developing countries. It is estimated that in India
is attributed to &oea.Thus d&oea represent is a major public health problem.
estimate of occurrence of this disease is not available. dysentery due to various causes
has been reported throughout India In addition to this, there are frequent outbreaks of
epidemics of dysentery. For example. the 1984 epidemic of dysentery in West Bengal. /
Cholera is an acute infection of the small intestine by a microorganism known as
Vibrio-Cholera. The disease is manifested by watery diarrhoea Cholera has been known
and feared for centuries because of its occurrence in epidemics resulting in high
mortality and social disruption. In certain regions of our country like Maharashtra,
Tamil Nadu, Madhya Pradesh, West Bengal. cholera forms an endemic disease. The
organism produces a toxin into the gut due to which the manifestation of the disease
Occllrs.
In this unit we will be learning about these three main food borne diseases.
0bjectives
After studying this, unit you will be able to :
identify the types, causes and spread of diarrtroea, dysentery and cholera
enumerate the symptoms and complications of diarrhoea. dysentery and cholera, and
describe the factors in control, prevention and management of these diseases.
,Food Borne Diseases, Food
Infections and Intoxication 112 DIARRHOEA
What is Diarrhoea ?
\
Diarrhoea is a sympton characterised by the sudden onset of frequent stools of watery
consistency abdominal pain, cramping, weakness and sometimes fever and vomiting.
Diarrhoea does not always mean many motions. Even one watery motion can be
I
diarrhoea. Diarrhoea is most often caused by :
eating food that is dirty or stale
drinking dirty water
iI
eating with dirty hands or 1
using dirty vessels. I
Diarrhoea occurs so often that sometimes people don't take it seriously. ,
.1
But diarrhoea is very dangerou~speciallyin very small or weak children.
That is why you must start treating your child as soon as she passes even one watery
I
motion.
Why diarrhoea is dangerous?
Diarrhoea is very dangerous especially in very'small an weak children. You should
1
know that the danger is in the loss of fluids and l y t e s from the body. This
condition is otherwise known as dehydration (Figure 11.1). If the dehydration is very
severe it may even cause death. Hence it is very essential to identify the severity of
dehydration in a subject with diarrhoea
-- z
pg.11.1: Dehydration
When a child is without water everything in his body seems to dry up. You must take ,
the child to the doctor at once, if hdshe has any one of these danger signs:
, 1) Her eyes look sunken and dry. She has no tears. Common Food Borne ,
Diseases-I
2) Her tongue is dry. She feels thirsty.
3) The soft spot on a baby's head gets sunken.
4) The skin loses its firmness and looks wrinkled.
5) If the skin is pinched, it stays folded for a few seconds.
6) Her voice becomes hoarse.
7) She starts panting or breathing fast.
8) She faints or gets convulsions.
9) She passes little or no urine.
10) The stomach gets distended, especially in a malnourished child.
11.2.1 The Disease--What causes it? Who gets it? How and when
does it spread?
You know that diarrhoea is very common among children. What are the causative agents
and how does the infection spread are important aspects in the study of diarrhoea. We
will learn about these aspects in this sub-section. But first we begin our study by
learning about the types of diarrhoea.
Types of Diarrhoea : Diarrhoeas are of two types : (i) Acute and (ii) Chronic diarrhoea.
Acute Diarrhoea is a condition where diarrhoea occurs as an attack of sudden onset which
usually lasts for 3 to 7 days, but may last upto 10-14 days (iii) Chronic diarrhoea is a
condition where diarrhoea lasts for 3 weeks or more.
What Causes it?
In all the develophg countries diarrhoea occurs due to infection. Some 25 types of
organisms including bacteria, viruses and parasites have so far been identified as
causative factors of diarrhoeal diseases. The common and most jmpbrtant organisms in
causing diarrhoeas can be enumerated as follows :
a) Viruses : Rotavirus is the single most important cause of diarrhoea in infants
and children. However, several other groups of viruses also are known to cause
diarrhoea.
b) Bacteria : Several bacteria are known to be associated with causation of diarrhoea.
These include:
i) Escherichia coli : These are gram-negative bacilli. These bacilli are usually found
in the intestinal flora of normal persons and animals. Some of the E. Coli organisms
produce a toxin which causes diarrhoea. The other forms of E.Coli organisms do
not produce any toxin but can still cause diarrhoea.
ii) Shigellae : This bacillus is a major cause of diarrhoea in some countries. It affects
particularly children under 9 years of age. This organism produces inflammatory
reaction in the bowel by which diarrhoea occurs. Though the most common
I symptom is frequent passage of stools (10-70 in number per day) this may
sometimes be associated with passage of blood and mucus i.e., dysentery.
iii) Campylobacters : These are highly motile gram negative organisms. These do not
produce any toxin.
iv) Vibrio-Cholerae : 5-10 per cent of cases of diarrhoeas in endemic areas are found
to be caused by the organism vibrio-cholerae. Cholera is separately discussed in
Unit 11.1.3 in detail.
v) Salmonella : These organisms are of various types. Only a few of them are
known to cause diarrhoea. Infection by these organisms is known as Salmonellosis.
c) Other infections :
i) Giardia : These organisms are identified to be present in the duodenum and
jejunum of gastrointestinal tract. The organisms can be present in large numbers.
Diarrhoea produced due to these organisms is known as giardiasis.
, ~ o o dBorne Dlseanes,~ o o d ii) Amoebiasis : Described elsewhere. See parasitic infestations (Unit 13).
Infections and Intoxlcrtlon
The mechanisms by which various organisms produce d i i o e a are varied. Some cause
little or no change in the lining of the intestine, while others cause considerable damage
to some areas of the wall of intestines. Some organisms act directly on the walls of
intestine while others act by way of the toxins they produce.
Diarrhoea may also occur due to some non-infectious forms of diseases, e.g., in diseases
like kwashiorkor-a form of malnutrition, sprue, coeliac disease and pellagra. Diarrhoea
in a new born is unusual. But if it occurs it may be mostly due to some congenital
defects like enzyme deficiencies. It may also be due to systemic infections like
septicaemia etc.
Diarrhoea may also occur in a child due to inability to digest milk, difficulty in
digesting a new food, allergy to certain foods and food poisoning. Over eating of unripe
fruit, spicy, heavy, greasy foods can also cause diarrhoea. Side effects of certain drugs
and use of laxatives, purges and certain poisons are also known to cause diarrhoea.
What is the reservoir of infection
For some organisms causing diarrhoea, man is the main reservoir, e.g., E. coli, Shigella,
V. cholerae, giardia etc. Animals also form an important reservoir for spread of diarrhoea
due to organisms like Campylobacter and Salmonella.
Who gets diarrhoea?
Age : Diarrhoea can occur at any age but it is more common in children. Certain studies
have shown that children in crawling age are more prone for diarrhoeas.
Sex : Both sexes are equally vulnerable to diarrhoea.
Malnutrition : A malnourished child gets more frequent and more severe forms of
diihoea, when compared to a normal healthy child.
Social factors : Occurrence of diarrhoeas is known to be more in low socio-economic
conditions. Poverty, overcrowding, ignorance and faulty feeding habits form one
spectrum of these conditions. Lack of proper sanitary facilities and inadequate and
unhygienic water supply, lack of personal hygiene are some of the other important
factors which reinforce the causation and perpetuation of diarrhoeas in such
communities.
Seasons : Diarrhoeas are more prevalent in rainy seasons when chances of contamination
of drinking water are more. Generally the subsoil water level in the ground rises and
there will be increase in the fly breeding during rainy season. As the rivers, streams
and tanks get filled with fresh water, possibility of enby of pollutants into water can
occur.
How does Diarrhoea Spread?
The diarrhoeas are spread mostly by oro-faecal route. The disease gets transmitted by
water, food or direct transmission.
Incubation period and period 4 communicability : As there are numerous organisms and
causes involved in the causation of diarrhoea, the incubation period and period of
communicability vary according to the causative factor.
11.2.2 Symptoms and complications of diarrhoea
Table 11.1 gives the manifestations of various grades of dehydration. If the subject
suffers from two or more such manifestations from a particular grade, he can be
categorised as suffering from respective grade of dehydration.
For example if an individual has more than 10 loose motions a day along with frequent
vomiting and his condition is bad. He is unconscious and his pulse is very weak.
Looking at these symptoms/manifestations we can say he is suffering from severe
dehydration.
10
11.1 Introduction
11.2 Diarrhoea
11.2.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.2.2 Symptoms and complications of dianhoea
11.2.3 Control. prevention and management of diarrhoea
t 11.3 Dysentery
i 11.3.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.3.2 Symptoms and complications of dysentery
11.3.3 Control. prevention and management of dysentery
I 11.4 Cholera
11.4.1 The Diseases -What causes it? Who gets it? How and when does it spread?
11.4.2 Symptoms and complications of cholera
11.4.3 Management. control and prevention of cholera
11.5 Let Us Sum Up
11.6 Glossary
11.7 Answers to Check Your Progress Exercises
Diarrhoea, dysentery and cholera are the major cause of sickness and death mostly
amongst children. in almost all the developing countries. It is estimated that in India
is attributed to &oea.Thus d&oea represent is a major public health problem.
estimate of occurrence of this disease is not available. dysentery due to various causes
has been reported throughout India In addition to this, there are frequent outbreaks of
epidemics of dysentery. For example. the 1984 epidemic of dysentery in West Bengal. /
Cholera is an acute infection of the small intestine by a microorganism known as
Vibrio-Cholera. The disease is manifested by watery diarrhoea Cholera has been known
and feared for centuries because of its occurrence in epidemics resulting in high
mortality and social disruption. In certain regions of our country like Maharashtra,
Tamil Nadu, Madhya Pradesh, West Bengal. cholera forms an endemic disease. The
organism produces a toxin into the gut due to which the manifestation of the disease
Occllrs.
In this unit we will be learning about these three main food borne diseases.
0bjectives
After studying this, unit you will be able to :
identify the types, causes and spread of diarrtroea, dysentery and cholera
enumerate the symptoms and complications of diarrhoea. dysentery and cholera, and
describe the factors in control, prevention and management of these diseases.
,Food Borne Diseases, Food
Infections and Intoxication 112 DIARRHOEA
What is Diarrhoea ?
\
Diarrhoea is a sympton characterised by the sudden onset of frequent stools of watery
consistency abdominal pain, cramping, weakness and sometimes fever and vomiting.
Diarrhoea does not always mean many motions. Even one watery motion can be
I
diarrhoea. Diarrhoea is most often caused by :
eating food that is dirty or stale
drinking dirty water
iI
eating with dirty hands or 1
using dirty vessels. I
Diarrhoea occurs so often that sometimes people don't take it seriously. ,
.1
But diarrhoea is very dangerou~speciallyin very small or weak children.
That is why you must start treating your child as soon as she passes even one watery
I
motion.
Why diarrhoea is dangerous?
Diarrhoea is very dangerous especially in very'small an weak children. You should
1
know that the danger is in the loss of fluids and l y t e s from the body. This
condition is otherwise known as dehydration (Figure 11.1). If the dehydration is very
severe it may even cause death. Hence it is very essential to identify the severity of
dehydration in a subject with diarrhoea
-- z
pg.11.1: Dehydration
When a child is without water everything in his body seems to dry up. You must take ,
the child to the doctor at once, if hdshe has any one of these danger signs:
, 1) Her eyes look sunken and dry. She has no tears. Common Food Borne ,
Diseases-I
2) Her tongue is dry. She feels thirsty.
3) The soft spot on a baby's head gets sunken.
4) The skin loses its firmness and looks wrinkled.
5) If the skin is pinched, it stays folded for a few seconds.
6) Her voice becomes hoarse.
7) She starts panting or breathing fast.
8) She faints or gets convulsions.
9) She passes little or no urine.
10) The stomach gets distended, especially in a malnourished child.
11.2.1 The Disease--What causes it? Who gets it? How and when
does it spread?
You know that diarrhoea is very common among children. What are the causative agents
and how does the infection spread are important aspects in the study of diarrhoea. We
will learn about these aspects in this sub-section. But first we begin our study by
learning about the types of diarrhoea.
Types of Diarrhoea : Diarrhoeas are of two types : (i) Acute and (ii) Chronic diarrhoea.
Acute Diarrhoea is a condition where diarrhoea occurs as an attack of sudden onset which
usually lasts for 3 to 7 days, but may last upto 10-14 days (iii) Chronic diarrhoea is a
condition where diarrhoea lasts for 3 weeks or more.
What Causes it?
In all the develophg countries diarrhoea occurs due to infection. Some 25 types of
organisms including bacteria, viruses and parasites have so far been identified as
causative factors of diarrhoeal diseases. The common and most jmpbrtant organisms in
causing diarrhoeas can be enumerated as follows :
a) Viruses : Rotavirus is the single most important cause of diarrhoea in infants
and children. However, several other groups of viruses also are known to cause
diarrhoea.
b) Bacteria : Several bacteria are known to be associated with causation of diarrhoea.
These include:
i) Escherichia coli : These are gram-negative bacilli. These bacilli are usually found
in the intestinal flora of normal persons and animals. Some of the E. Coli organisms
produce a toxin which causes diarrhoea. The other forms of E.Coli organisms do
not produce any toxin but can still cause diarrhoea.
ii) Shigellae : This bacillus is a major cause of diarrhoea in some countries. It affects
particularly children under 9 years of age. This organism produces inflammatory
reaction in the bowel by which diarrhoea occurs. Though the most common
I symptom is frequent passage of stools (10-70 in number per day) this may
sometimes be associated with passage of blood and mucus i.e., dysentery.
iii) Campylobacters : These are highly motile gram negative organisms. These do not
produce any toxin.
iv) Vibrio-Cholerae : 5-10 per cent of cases of diarrhoeas in endemic areas are found
to be caused by the organism vibrio-cholerae. Cholera is separately discussed in
Unit 11.1.3 in detail.
v) Salmonella : These organisms are of various types. Only a few of them are
known to cause diarrhoea. Infection by these organisms is known as Salmonellosis.
c) Other infections :
i) Giardia : These organisms are identified to be present in the duodenum and
jejunum of gastrointestinal tract. The organisms can be present in large numbers.
Diarrhoea produced due to these organisms is known as giardiasis.
, ~ o o dBorne Dlseanes,~ o o d ii) Amoebiasis : Described elsewhere. See parasitic infestations (Unit 13).
Infections and Intoxlcrtlon
The mechanisms by which various organisms produce d i i o e a are varied. Some cause
little or no change in the lining of the intestine, while others cause considerable damage
to some areas of the wall of intestines. Some organisms act directly on the walls of
intestine while others act by way of the toxins they produce.
Diarrhoea may also occur due to some non-infectious forms of diseases, e.g., in diseases
like kwashiorkor-a form of malnutrition, sprue, coeliac disease and pellagra. Diarrhoea
in a new born is unusual. But if it occurs it may be mostly due to some congenital
defects like enzyme deficiencies. It may also be due to systemic infections like
septicaemia etc.
Diarrhoea may also occur in a child due to inability to digest milk, difficulty in
digesting a new food, allergy to certain foods and food poisoning. Over eating of unripe
fruit, spicy, heavy, greasy foods can also cause diarrhoea. Side effects of certain drugs
and use of laxatives, purges and certain poisons are also known to cause diarrhoea.
What is the reservoir of infection
For some organisms causing diarrhoea, man is the main reservoir, e.g., E. coli, Shigella,
V. cholerae, giardia etc. Animals also form an important reservoir for spread of diarrhoea
due to organisms like Campylobacter and Salmonella.
Who gets diarrhoea?
Age : Diarrhoea can occur at any age but it is more common in children. Certain studies
have shown that children in crawling age are more prone for diarrhoeas.
Sex : Both sexes are equally vulnerable to diarrhoea.
Malnutrition : A malnourished child gets more frequent and more severe forms of
diihoea, when compared to a normal healthy child.
Social factors : Occurrence of diarrhoeas is known to be more in low socio-economic
conditions. Poverty, overcrowding, ignorance and faulty feeding habits form one
spectrum of these conditions. Lack of proper sanitary facilities and inadequate and
unhygienic water supply, lack of personal hygiene are some of the other important
factors which reinforce the causation and perpetuation of diarrhoeas in such
communities.
Seasons : Diarrhoeas are more prevalent in rainy seasons when chances of contamination
of drinking water are more. Generally the subsoil water level in the ground rises and
there will be increase in the fly breeding during rainy season. As the rivers, streams
and tanks get filled with fresh water, possibility of enby of pollutants into water can
occur.
How does Diarrhoea Spread?
The diarrhoeas are spread mostly by oro-faecal route. The disease gets transmitted by
water, food or direct transmission.
Incubation period and period 4 communicability : As there are numerous organisms and
causes involved in the causation of diarrhoea, the incubation period and period of
communicability vary according to the causative factor.
11.2.2 Symptoms and complications of diarrhoea
Table 11.1 gives the manifestations of various grades of dehydration. If the subject
suffers from two or more such manifestations from a particular grade, he can be
categorised as suffering from respective grade of dehydration.
For example if an individual has more than 10 loose motions a day along with frequent
vomiting and his condition is bad. He is unconscious and his pulse is very weak.
Looking at these symptoms/manifestations we can say he is suffering from severe
dehydration.
10
