Typhoid is caused by the bacterium Salmonella Typhi. It is transmitted through the fecal-oral route, usually through contaminated food or water. The disease causes a sustained fever for 3-4 weeks along with gastrointestinal symptoms. Prevention focuses on control of reservoirs through treatment and isolation of cases, improved sanitation and hygiene practices, and immunization in endemic areas.

1. Typhoid
Presented by
Deepa Manandhar
Lecturer
Community Health Nursing

2. typhoid
• Typhoid is a continuous fever lasting 3-4 weeks, usually with
headache, bronchitis and gastrointestinal symptoms.

3. Agent factors
a) AGENT : Typhoid is caused by Salmonella Typhi. It is readily killed
on heating on 60 degree Celsius for 15 minutes or on boiling. It can
survive in ice for considerable time and for some days in fresh water. S.
typhi has three main antigens-O, H and Vi

4. Agent factors
(b) RESERVOIR OF INFECTION : Man is the only known reservoir of
infection, viz cases and carriers.

5. Agent factors
(c) SOURCE OF INFECTION : The primary sources of infection are
faeces and urine of cases or carriers; the secondary sources
contaminated water, food, fingers and flies. There is no evidence that
typhoid bacilli are excreted in sputum or milk.

6. Host factors
(a) Age : Typhoid fever may occur at any age. Highest incidence of this
disease occurs in the 5-19 years of age group.
(b) Sex: More cases are reported among males than females. But carrier
rate is more in females.

7. Host factors
(c) Immunity:
All ages are susceptible to infection. Antibody may be stimulated by the
infection or by immunization; however, the antibody to the somatic
antigen (0) is usually higher in the patient with the disease, and the
antibody to the flagellar antigen (H) is usually higher in immunized
individuals.

8. Environmental and Social factors
• Observed throughout the year.
• Peak incidence is reported during July-September. This period
coincides with rainy season and an increase in fly population.
• Outside the human body, the bacilli are found in water, ice, food, milk
and soil for varying period of time.

9. Incubation period
• Usually 10-14 days.

10. Mode of transmission
• Typhoid fever is transmitted via the faecal-oral route or urine-oral
routes

11. Clinical features

12. Clinical features
 the fever rise daily in a step ladder pattern during the first week,
remains continuously high during the second and third weeks and
comes down gradually by the fourth week.
 Later, splenomegaly, abdominal distension, tenderness, relative
bradycardia and occasionally meningismus appear.
 The rash (rose spots), is a pink papule 2 to 3 mm in diameter that
fades on pressure is found principally on the trunk which commonly
appears during the 2nd week of disease and disappears by 3-4 days.

13. Clinical features

14. Preventive measures
• There are generally three lines of defence against typhoid fever :
1. control of reservoir
2. control of sanitation
3. immunization.
• The weakest link in the chain of transmission is sanitation which is
amenable to control.

15. Control of reservior
• The usual methods of control of reservoir are their identification,
isolation, treatment and disinfection.

16. Control of sanitation
• Protection and purification of drinking water supplies, improvement of
basic sanitation, and promotion of food hygiene are essential measures
to interrupt transmission of typhoid fever.

17. immunization
• A complementary approach to prevention is immunization.
• It is recommended to: those living in endemic areas, household
contacts, groups at risk of infection such as school children and
hospital staff, travelers proceeding to endemic areas, and those
attending melas and yatras.

18. Worm infestation

19. Worm infestation
Soil-transmitted helminth infections refer to a group of parasitic
diseases in humans caused by intestinal roundworms (ascariasis),
hookworms (Necator americanus and Ancylostoma duodenale) and
whipworm (Trichuris trichiura). They are common infections
worldwide.

20. Mode of transmission
Soil-transmitted helminths are transmitted by eggs that are passed in the
faeces of infected people, as adult worms live in the intestine where they
produce thousands of eggs each day. In areas that lack adequate
sanitation, these eggs contaminate the soil. This can happen in several
ways :

21. Mode of transmission
(a) eggs that are attached to vegetables and salads are
ingested
(b) eggs are ingested from contaminated water sources
(c) eggs are ingested by children who play in soil and then
put their hands in their mouth without washing them.

22. Ascaris lumbricoides
An infection of the intestinal tract caused by the adult, Ascaris
lumbricoides and clinically manifested by vague symptoms of nausea,
abdominal pain and cough. Live worms are passed in the stool or
vomited. Occasionally, they may produce intestinal obstruction or may
migrate into the peritoneal cavity.

23. Agent
Ascaris lumbricoides lives in the lumen of small intestine, where it
moves freely. Sexes are separate.
The female measures 20-35 cm in length, and the male 12-30 cm.

24. Agent
 Egg production is very heavy - an estimated 2,40,000 eggs per day by
each female.
 The eggs are excreted in the faeces.
 They become embryonated in the external environment and become
infective in 2-3 weeks.

25. Reservoir of infection
 Man is the only reservoir.

26. host
HOST : Infection rates are high in children; they are the most important
disseminators of infection. Adults seem to acquire some resistance.

27. environment
• Of the various ecological factors regulating the population of Ascaris
eggs, the most important ones are the temperature, moisture, oxygen
pressure and ultra-violet radiation from the sunlight.
• A low temperature inhibits the development of eggs.
• Clay soils are most favourable for the development of ascariasis eggs

28. Human habits

29. Period of communicability
Until all fertile females are destroyed and stools are negative.

30. Incubation period
18 days to several weeks.

31. Clinical features
The symptoms are related to the number of the worms harboured.
People with light infection usually have no symptoms.
Heavier infections can cause a range of symptoms including intestinal
manifestations like diarrhoea, abdominal pain; general malaise,
weakness, impaired cognitive and physical development.

32. Clinical features
 The WHO definition of heavy infection of roundworm is ~ 50,000
eggs per gram of faeces. The larvae migration may cause fever, cough,
sputum formation, asthma, skin rash, oesinophilia.
 The adult roundworm aggregate masses can cause volvulus, intestinal
obstruction or intessusception; and wandering worm can cause bowel
perforation in the ileococcal region, blocking of common bile duct or
may come out with vomit.

33. hookworm

34. hookworm
• Hookworm infection is defined as "any infection caused by
Ancylostoma duodenale or Necator americanus". They may occur as
single or mixed infections in the same person.

35. agent
• AGENT : Adult worms live in the small intestine, mainly jejunum
where they attach themselves to the villi. Males measure 8 to 11 mm,
and females 10 to 13 mm in length with dorsally curved anterior end.
• Eggs are passed in the faeces in thousands; one female A duodenale
produces about 10,000-30,000 eggs and one female N. americanus
about 5,000-10,000 eggs per day.

36. agent
• When deposited on warm, moist soil, a larva rapidly develops in the
egg and hatches after 1 to 2 days.
• The newly hatched larva (rhabditiform larva) moults twice in the soil
and becomes a skin-penetrating third stage infective larva within 5 to
10 days.

37. reservoir
Man is the only important reservoir of human hookworm infection.

38. Infective material
Faeces containing the ova of hookworms. However, the immediate
source of infection is the soil contaminated with infective larvae.

39. infectivity
As long as the person harbours the parasite.

40. Host factors
(a) AGE AND SEX: All ages and both sexes are susceptible to infection.
In endemic areas, the highest incidence is found in the age group, 15 to
25 years.
(b) NUTRITION : Studies indicate that malnutrition is a predisposing
factor; the chronic disabling disease does not occur in the otherwise
healthy individual who is well-nourished and whose iron intake is
adequate.

41. Host factors
HOST-PARASITE BALANCE : In endemic areas, the inhabitants
develop a host-parasite balance in which the worm load is limited. They
harbour the parasite without manifesting clinical signs and symptoms.
In some areas, the infection rate may be 100 per cent, but most
infections are light and only a small proportion of the people are heavily
infected.

42. Host factors
(d) OCCUPATION :higher prevalence in agricultural than in town
workers, and in many tropical countries, it is an occupational disease of
the farming community.

43. environment
(a) SOIL : the type of soil that favours the survival of hookworm larvae
is a damp, sandy or friable soil with decaying vegetation.
(b) TEMPERATURE : A temperature of 24 to 32 deg. C is considered
favourable for the survival of the larvae.
(c) OXYGEN : This is required for the growth and development of the
larvae.
(d) MOISTURE : Moisture is necessary for survival.

44. environment
e) RAINFALL: A rainfall of 40 inches (100 cm) and above is considered
a favourable environmental factor
(f) SHADE : Direct sunlight kills the larvae whereas shade protects
them.
(g) HUMAN HABITS : These include indiscriminate defecation, using
the same places for defecation, going barefoot, farming practices using
untreated sewage, children wading in the infected mud with bare-feet
and hands.

45. Mode of transmission
Hookworms (infective larvae) enter the body, usually feet,
penetrating the skin.
Ancylostoma may also be acquired by oral route by direct
ingestion of infective larva via contaminated fruits and
vegetables.

46. Incubation period
Following infection, the prepatent period for N. americanus is 7 weeks
while that for A duodenale is unpredictable, ranging from 5 weeks to 9
months.

47. Prevention and control
Discussion