This document discusses common parasitic infections in humans. It covers: 1. Types of parasites including protozoa, helminths (flatworms and roundworms), and ectoparasites. 2. Key protozoan parasites like Entamoeba histolytica, Giardia lamblia, Plasmodium spp. (which cause malaria), and their related diseases. 3. Important helminthic infections caused by tapeworms, flukes, roundworms, and filarial worms and their transmission and detection.

1. Common Parasitic
Infections
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2. Parasites
Pin worms
Amoeba
Flukes
Fish Tape worms Wipe worms
Dwarf Tape worms
Hook worms DR. Ram Sharan Mehta, MSND,
Tape worm Mouth
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3. Cutaneous leishmaniasis
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4. leishmaniasis
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5. Scabies
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6. Scabies
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7. This skin disorder is due to infestation of the skin
by fly larvae . The most common fly causing dermal
myiasis is the screw worm fly.
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8. Babesia: Babesiosis is a vector-borne illness usually
transmitted deer tick or black legged tick
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9. Parasite infection in lung
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10. Lyme disease by Tick bite
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11. Loa eye parasite in Eye
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12. Eye Worm
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13. Round worm
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14. Ascaris In Mouth and Nose
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15. Worm in Head
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16. Parasites In Humans
Some facts:
• Humans may be a host to over 100
different types of parasites.
• In recent medical studies it has been
estimated that 85% of the North
American adult population has at least
one form of parasites living in their
bodies.
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17. DR. Ram Sharan Mehta, MSND,
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18. 1. Types of parasites
a. Protozoa
– Single celled, Organized cellular structure
– May ingest solid particles
– Require aquatic (watery) environment
– Reproduce by binary fission at some point in life cycle
b. Helminths (worms)
– Multicellular, Organized internal structure; includes
• Platyhelminths (flatworms)
• Nematoda (roundworms)
c. Ectoparasites
– Insects and arachnida (spider, scorpions) found on the skin.
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19. Classification, disease
and detection of parasites
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20. DR. Ram Sharan Mehta, MSND,
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21. Protozoa
– Amoebae
• Form cytoplasmic protrusions
(pseudopodia).
• Occur as trophozoites (active, growing) and
cyst (environmentally protected) forms.
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22. • Pathogens
–Entamoeba histolytica
• Disease - Ranges from: asymptomatic,
diarrhoea to dysentery and liver disease.
• Transmission - Fecal-oral - contaminated
water/food, (especially in the tropics).
– Poor living conditions.
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23. Flagellates
– Propelled by flagella.
– May occur in trophozoites and cyst forms.
– Have shape because of rigid outer wall.
• Pathogens - Giardia lamblia
• Disease - Ranges from asymptomatic to
acute or chronic diarrhoea
• Transmission - Fecal-oral,
waterborne,World wide.
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24. • Trichomonas vaginalis
– Disease - Vaginitis.
– Transmission - Sexual.
– Detection - Microscopy of discharge,
culture.
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25. • Trypanosoma spp
– Cause: Trypanosomiasis (Sleeping sickness)
– Disease - Fever, encephalitis; cardiac
complications.
– Transmission - Fly, Bug
– Detection - Parasites stained on blood
smears, serology.
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26. • Sporozoa
– Mature forms are non-motile.
– Complex life cycles.
– Pathogens - Plasmodium spp. Cause malaria.
– Disease - Episodic fevers, anaemia - life
threatening!
– Transmission - Mosquito bites.
– Detection: Parasites stained on blood film.
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CON, BPKIHS

27. • Cryptosporidium parvum
– Disease: watery diarrhea (chronic in
immunosuppressed)
– Transmission: fecal-oral, water borne,
animals (zoonosis), world wide distribution
– Detection: microscopy of stool using special
stains
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28. • Cyclospora cayetanensis
–Disease - Watery diarrhea, similar
to above.
–Transmission - Fecal - oral,
especially in tropics.
–Detection - As for Cryptosporidium.
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29. • Toxoplasma gondii
– Disease - Mostly asymptomatic infection,
but new infection in pregnancy causes
fetal malformations; also infection in
immuno-suppressed.
– Transmission - By poorly cooked meat,
from cat stool, rarely water.
– Detection - By serology.
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30. DR. Ram Sharan Mehta, MSND,
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31. DR. Ram Sharan Mehta, MSND,
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32. • Helminths
– Platyheminths (flatworms)
• Cestodes – “tapeworms”
• Ribbon like, segmented. No digestive system, adult
attached to gut wall by scolex, larval forms in
tissues.
• Life cycle Definitive Host (gut contains adult
worms )
• Environment ( Ova )
• Intermediate Host ( tissues contain larval stage)
• When the intermediate host is eaten by the
definitive host, the adult worm develops in the gut
from the larval form, and later produces ova.
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33. DR. Ram Sharan Mehta, MSND,
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34. • Principle Pathogens
– Taenia saginata,Taenia solium
• Disease: - Abdominal discomfort (man is
definitive host {i.e. has adult}).
• Transmission: - Larval forms ingested in food.
• Detection: - Identification of ova or adult
segments in stool.
– Some cestodes infect humans by the adult
form in the gut, some infect by larval forms
in tissues, and some infect in both forms.
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CON, BPKIHS

35. –Cysticercosis (T. solium larvae)
• Disease -Cysts throughout the body
tissues.
• Transmission - Ova are ingested;
• Detection - Serology, also x-ray,
ultrasound, and other methods to
detect mass lesions.
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CON, BPKIHS

36. • Pathogens - Schistosoma spp.
(schistosomiasis).
• Disease - Effects of inflammation,
hematuria.
• Transmission - Penetration of skin .
• Detection - Ova in stool/urine depending
on species of schistosome.
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37. –Nematodes (roundworms)
• Disease - Abdominal pain/discomfort
(most found in the gut).
• Transmission - Fecal-oral via ova in
stool.
• Detection
–Recognition of ova using stool
microscopy.
–Identification of adult worms.
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CON, BPKIHS

38. –Hookworms
• Disease - Chronic blood loss.
• Transmission - Larvae penetrate
skin.
• Detection - Identification of ova
or larvae in stool.
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CON, BPKIHS

39. –Filaria - filariasis
• Disease - Fevers, elephantiasis,
swelling and deformity of limbs,
genitalia.
• Transmission - Mosquito borne/Sand
fly.
• Detection - Marasites (microfilaria)
stained on blood film.
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CON, BPKIHS

40. Filarisis
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41. Elephantitis
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42. Ectoparasites
– Colonize the body vs. Micropredators
that bite only.
• Insects - ( 6 legs) - fleas, head-, body-
and pubic lice (singular – Louse)
• Arachnida - ( 8 legs, but can have 6 in
immature form) - ticks, mites
– Their importance is as vectors of
disease and to a lesser extent
cosmetic.
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43. DR. Ram Sharan Mehta, MSND,
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44. DR. Ram Sharan Mehta, MSND,
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45. DR. Ram Sharan Mehta, MSND,
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46. Adaptations to a parasitic existence
• Loss of structures or enzymes, e.g. GI tract.
• Development of pathogenic adaptations, e.g.
mechanisms of attachment (hookworms).
• Defense mechanisms, e.g. resistance to
digestion (nematodes).
• Increased reproductive capacity, eg. Ascaris.
Some parasites require infection of a host to
complete their lifecycles.
Other parasites may be free living in the environment
and do not need to cause infection to persist.
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CON, BPKIHS

47. Detection of GI protozoa –
amoebae / flagellates
• Microscopic identification of organisms
from a concentrated extract of stool.
• Microscopic identification of organisms
using a stained slide made from a filtered
stool suspension.
Note: Parasite preservative kills all organisms;
therefore, a preserved specimen cannot be used
for culture.
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CON, BPKIHS

48. Thank You
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49. ARTHROPOD INFECTIONS/INFESTATIONS OF THE SKIN:
Insect infections/infestations
1. Louse (Anoplura) infestations: Pediculus
2. Blood-feeding bugs (Hemiptera)
3. Fleas (Siphonaptera)
4. Blood-feeding flies and myiasis (Diptera)
• Cutaneous myiasis – calliphorid blowflies; putsi flies,
human botflies
• Gastrointestinal myiasis – calliphorid blowflies
• Ophthalmomyiasis – sheep nasal bot fly, Oestrus ovis41;
screw worms
• Genitourinary myiasis – calliphorid blowflies.
• Sanguinivorous myiasis – the Congo Floor Maggot
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50. Arachnid infections/infestations
1. Mites
2. Ticks
3. Argasid ticks
4. Ixodid ticks
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51. Common Symptoms of Parasites
• Constipation: Some worms, because of
their shape and large size. can physically
obstruct certain organs. Heavy worm
infections can block the common bile duct
and the intestinal tract, making elimination
infrequent and difficult.
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CON, BPKIHS

52. Diarrhoea: Certain parasites, primarily protozoa, produce a
prostaglandin (hormonelike substances found in various
human tissues) which creates a sodium and chloride loss
that leads to frequent watery stools. The diarrhoea process
in parasite infection is, therefore, a function of the parasite,
not the body's attempt to rid itself of an infectious organism.
Gas and Bloating: Some parasites live in the upper small
intestine where the inflammation they produce causes both
gas and bloating. The situation can be magnified when
hard-to-digest foods such as beans and raw fruits and
vegetables are eaten. Persistent abdominal distention is a
frequent sign of hidden invaders. These gastrointestinal
symptoms can persist intermittently for many months or
years if the parasites are not eliminated from the body.
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CON, BPKIHS

53. Irritable bowel syndrome: Parasites can irritate inflame,
coal, the intestinal cell wall, leading to a variety of
gastrointestinal symptoms and malabsorption of vital
nutriens, particularly fatty substances. This malabsorption
leads to bulky stools and steatorrhea (excess far in
feces).
Joint and muscle aches and pains: Parasites are
known to migrate to encyst (become enclosed in a sac) in
joint fluids, and worms can encyst in muscles. Once Ads
happens, pain becomes evident and is often assumed to
be caused by arthritis Joint and muscle pains and
inflammation are also the result of tissue damage caused
by some parasites of the body's ongoing immune
response to then- presence.
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CON, BPKIHS

54. Anaemia: Some varieties of intestinal worms attach
themselves to the mucosal lining of the intestines and
then leach nutrients from the human host. If they are
present in large enough numbers, they can create
enough blood loss to cause a type of iron deficiency or
pernicious
Allergy: Parasites can irritate and sometimes perforate
the intestinal lining, increasing bowel permeability to
large undigested molecules. This can activate the body's
immune response to produce increased levels of
eosinophils, one type of the body's fighter cells. The
eosinophils can inflame body tissue, resulting in an
allergic reaction. Like allergy, parasites also trigger an
increase in the production of immunoglobulin E (IgE).
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CON, BPKIHS

55. • Skin conditions: Intestinal worms can cause
hives, rashes, weeping eczema, and other
allergic-type skin reactions. Cutaneous ulcers,
swellings and sores, popular lesions, and itchy
dermatitis can afl result from protozoan invasion.
Granuiomas: Granulomas are tumour-like
masses that encase destroyed large or parasitic
eggs. They develop most often in the colon or
rectal walls but can also be found in the lungs
liver, peritoneum, and uterus.
DR. Ram Sharan Mehta, MSND,
CON, BPKIHS

56. Nervousness: Parasitic metabolic wastes and toxic substances can
serve as irritants to the central nervous system. Restlessness and
anxiety are often the result of the systemic parasite infestation. (After
completing a herbal cleanse, many people swear that their
persistently grouchy mates or relatives have become a lot more
pleasant and patient. "The most famous tapeworm of recent years
belonged to the late opera singer Maria Callas. She had a serious
weight and skin problem. When the tapeworm was detected and
removed, ha" weight dropped, her skin improved and her
temperament mellowed," says Gittleman.)
Sleep disturbances: Multiple awakening during the night particularly
between 2 and 3 AM, are possibly caused by the body's attempts to
eliminate toxic wastes via the liver. According to Chinese medicine,
these hours are governed by the liver. Sleep disturbances are also
caused by nocturnal exits of certain parasites through the anus,
creating the intense discomfort and itching.
DR. Ram Sharan Mehta, MSND,
CON, BPKIHS

57. Teeth grinding: Bruxism - abnormal grinding, clenching,
and gnashing of the teeth - has been observed in cases
of parasitic infection. These symptoms are most
noticeable among sleeping for children. Bruxism may be
a nervous response to the internal foreign irritant.
Chronic fatigue: Chronic fatigue symptoms include
tiredness, flu-like complaints, apathy, depression,
impaired concentration, and faulty memory. Parasites
cause these physical, mental, and emotional symptoms
through malnutrition resulting from malabsorption of
proteins, carbohydrates, fats, and especially vitamins A
and B-12.
DR. Ram Sharan Mehta, MSND,
CON, BPKIHS

58. • Immunie Dysfunction: Parasites depress
immune system functioning by decreasing the
secretion of immunoglobulin A (I&A). Their
presence continuously stimulates the system
response and over time can exhaust this vital
defense system, leaving the body open to bacterial
and viral infections.
The following conditions might also be tell-tale
signs of a parasitic invasion: weight gain,
excessive hunger, weight loss, bad taste in the
mouth and bad breath, asthma, diabetes, epilepsy,
acne, migraines, and even the biggest killers: heart
disease and cancer. CON, BPKIHS MSND,
DR. Ram Sharan Mehta,

59. Nematoda -
Roundworms
· Anisakis
· Ascaris Lumbricoides - Giant
Roundworm
· Enterobius Vermicularis - Pinworm
· Hookworms
· Loa Loa - Eye Worm - Subcutaneous
Filariasis
· Strongyloides Stercoralis
· Trichuris Trichiura - Whipworm
· Wuchereria Bancrofti - Lymphatic
Filariasis - Elephantiasis
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CON, BPKIHS

60. Trematoda -
Flukes
· Fasciola Hepatica - Liver Fluke
· Fasciolopsis Buski - Intestinal
Fluke
· Paragonimus Westermani - Lung
Fluke
· Schistosoma - Blood Flukes
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CON, BPKIHS

61. Cestoda -
Tapeworms
· Diphyllobothrium Latum - Fish
Tapeworm
· Hymenolepis Nana - Dwarf
Tapeworm
· Taenia Saginata - Beef Tapeworm
· Taenia Solium - Pork Tapeworm
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CON, BPKIHS

62. Protozoa
· Balantidium Coli
· Entamoeba Histolytica - Amoebiasis
· Giardia Intestinalis
· Leishmania
· Plasmodium Falciparum - Malaria
· Toxoplasma Gondii
· Trypanosoma Brucei - Sleeping Sickness
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CON, BPKIHS

63. Skin Parasites
· Cimex Lectularius - Bedbug
· Dermatobia hominis - Human Botfly
· Sarcoptes Scabiei - Scabies
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64. Thank You
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