4. • Ascaris is a genus of parasitic nematode worms known as the
"giant intestinal roundworms".
• One species, A. suum, typically infects pigs,
• while another, A. lumbricoides, affects human populations,
typically in sub-tropical and tropical areas with poor
sanitation.
12. TRANSMISSION
Ascariasis is not spread directly from one person to
another.
By the FAECAL-ORAL route, i.e., by ingestion of
infective eggs with food or drink.
Foods that are eaten raw such as salads and
vegetables readily convey the infection, and so is
polluted water.
13. • There is increasing evidence that dust may
play an important role in the dissemination of
ascaris in arid areas.
17. Symptoms Cont.
2. Symptoms associated with adult parasite in the intestine
• Usually asymptomatic
• Abdominal discomfort, nausea in mild cases
• Malnutrition
• Sometimes fatality may occur when mass of worm blocks the
intestine
22. Diagnosis
• Stool microscopy :
• Eosinophilia: eosinophilia can be found, particularly during
larval migration through the lungs
• Ultrasound: ultrasound exams can help to diagnose
hepatobiliary or pancreatic ascariasis.
• Endoscopic Retrograde Cholangiopancreatography (ERCP) :
A duodenoscope with a snare to extract the worm out of the
patient
24. Prevention
• Proper washing of the vegetables.
• Health education.
• Washing hands before meals.
• Mass treatment for the patients.
• Sanitary disposal for the feces.
• Avoid uses of feces as manures.
26. Morphology
1. Adults: They look like an odd piece
thread and are about 1cm.
2. They are white or light pinkish when
living. ♀is slightly larger than♂.
27. 2. Eggs: oval in shape, shell is thin and colorless.
Content is 2-8cells.
28. Acylostoma duodenale & Necator
americanus -- human hookworms
• Small nematodes (1-1.5 cm)
• Head is slightly bend (hook)
and the ‘mouth’ carries
characteristic teeth
(Ancylostoma) or plates
(Necator,
31. Pathogenesis and Clinical
Manifestations
• Skin penetration and
associated secondary
bacterial infection can
result in “ground itch”
• Pulmonary phase is
usually asymptomatic
• Intestinal phase: worms
attach to the mucosa and
feed on blood. Worms
continuously move to
new places exacerbating
bleeding
32. Hookworms
• The main concern with hook
worm disease is blood loss
• 0.03 ml to 0.26 ml (A.d) per
worm, up to 200 ml per day in
heavy infections
• Chronic heavy infection results
in anemia and iron deficiency
36. Prevention
1. sanitary disposal of night soil
2. individual protection
3. health education
4. cultivate hygienic habits
5. treat the patients and carriers.
41. Pathology and
Clinical Manifestation
• Pinpoint lesion on mucous membrane
• Flask-shaped ulcers
42. A. Intestinal amoebiasis
• a. dysentery: dysenteric stools (pus and blood
dysentery:
without feces). fever, dehydration, and
electrolyte abnormalities.
• b. non-dysenteric colitis
• c. appendicitis
• d. amoeboma: may become the leading point
of an intussusception or may cause intestinal
obstruction.
53. Food safety
• Thoroughly cook all raw foods.
• * Thoroughly wash raw
vegetables and fruits before
eating.
• * Reheat food until the internal
temperature of the food
reaches at least 167º
Fahrenheit.
• Wash your hands before
preparing food, before eating,
after going to the toilet or
changing diapers,
55. Epidemiology
Distribution
Worldwide distribution, endemic and epidemic.
Traveler diarrhea
Patients with variable immunodeficiency are
increasingly susceptible to infection with Giardia.
56. Epidemiology
Transmission source
Persons whose feces containing cysts
Monkeys and pigs can also be infected, the infected
pig may be a source of human infection.
Transmission
drinking contaminated water
Infected by
eating contaminated food
57.
58. Diagnosis
Pathogenic examination
(1) Fecal examination
(2) Duodenal fluid or bile examination
(3) Intestinal examination by gelatin capsule
60. Cysts have strong resistance
Cysts can keep alive 10 or more days in feces
Cysts are often waterborne, either by taking
inadequately treated municipal water supplies
of contaminated river or stream
Giardiasis is more common in travelers,
Immunodeficiency persons
61. Prevention and control
Treat the patients and cyst carriers
Metronidazole
Tinidazole
Treatment of the drinking water
Suspect water should be boiled or adequately
filtered to remove the infective cysts before
drinking.
63. fecal-oral
Animal to human
Contamination of
water supplies (result
of waste runoff)
*WATER-BORNE
MOST COMMON*
COMMON
64. SYMPTOMS
• Immunocompetent • Immunocompromised
– Mild self-limiting – 50 or more stools per
enterocolitis (watery day
bloodless diarrhea, – Dehydration (fatigue,
abdominal pain, nausea, abdominal cramping,
vomiting, and fever) and nausea)
– Common in AIDS
patients
65. LAB DIAGNOSIS
Microscopic exam
Acid
fast stain of stool
sample
Endoscopic biopsy of
small intestine
68. • Infectious agents are the OOCYSTS
• In immunocompromised patients ID50 is about 10
to 30 oocysts
69.
70. TREATMENT
• Immunocompetent • Immunocompromised
– Self-limiting – Cocktail therapy -used
to treat symptoms but
– Usually symptoms
NOT THE DISEASE
subside within 10
– Drugs include: letrazuril,
days azithromycin, paramycin,
and hyperimmune bovine
colostral
immunoglobulin
*The only immunity is previous exposure and
extent of this immunity is not known.*
71. PREVENTION
• Wash hands
• Wash fruits and
vegetables
• Avoid untreated water
• Treat contaminated
water
• MAINTAIN PROPER
HYGIENE!!
72. WATER PREVENTION
• Ozone
• UV light
• boiling
• “Chlorine not
effective against
crypto!!”
73.
74. CONTROL OF PROTOZOA IN
DRINKING WATER
Multiple barrier approach:
Filtration
Chemical inactivation- ozone, combination of
disinfectants
Medium-pressure ultraviolet light (UV)
Monitoring:
Presence of protozoa in raw water