1. HELMINTHS .

2. Objectives Epidemiology Clinical manifestations Diagnosis Treatment
Introduction/Background
Scientific classifications
Nematodes
Some species:
A.lumbricoides,N.americanus and A.duodenale
Morphological properties
Pathogenesis
Epidemiology
Clinical manifestations
Diagnosis
Treatment
Prevention

3. Introduction Definition:
Helminths are bilaterally symmetrical metazoa belonging to the Phylum Nematoda . Or
Multicellular parasitic worms which generally can be seen by naked eyes.
Parasitic worms that feed on a living host to gain nourishment and protection while causing poor nutrient absorption , weakness and disease in the host. Comprise groups of Nematodes, Round worms and Trematodes

4. Nematodes
Defition:
Round,elongated unsegmented , cylindrical worms parasitic in animals or plants or free living in soil or water

5. ASCARIS LUMBRICOIDES (Round worm).
ASCARIS LUMBRICOIDES
(Round worm)

6. Background A.lumbricoides:
Is a giant round worm of humans intestines growing up to 35cm in length. Resembles earthworm hence Lumbricus (Latin)
Most common parasitic worm
Responsible for disease known as Ascariasis
Causing infection to one sixth of the population worldwide

7. Ascaris lumbricoides Scientific classification: Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Ascaridida
Family: Ascarididae
Genus: Ascaris
Species: A.lumbricoides
Binomial naming: Ascaris lumbricoides

8. Morphology Adult worm lives in the small intestine of infected human
They are pale pink or flesh coloured when freshly passed in the in stool, but become white outside the body.
Mouth at anterior end has three finely denticulated lips one dorsal two ventro lateral
It has distinct groove(Genita girdle) surrounding the worm at level of vulvular opening which facilitates mating
It has single vagina branching to a pair genital tubules

9. Morphology cont….. Size: Male:2-4mm(diameter)x15-31mm(long)
Posterior end is curved ventrally to form a hook and has bluntly pointed end with two copulatory spicules.
Female: 3-6mm(diameter)x20-49mm(long)
Vulva is located in the interior end accounts for about 1/3 of its it is straight body length which is conical posteriorly.
Uteri may contain 27mil. Eggs at a time, 200,000 being laid per day.

10. Morphology cont…. Egg: Fertilized eggs are oval to round in shape
45-75µm long x35-50µm wide with thick outer shell
Bile stained to a golden brown colour
Has the outer coarsely mamillated albuminoid coat
Some eggs found in feces without outer mamillated coat(Decorticated eggs)
Unfertilised egg is longer up to 90µm and elliptical
The shell is thinner with outer mamillary coat scanty and irregular.
Unfertilised egg is relatively heavy does not float in saturated salt solution but fertilised does

11. Morphology cont….
Fertilized egg does not become infective immediately but undergo a period of incubation in the soil.
Eggs are resistant to adverse condition can for several years.
Development depends on nature of the soil and environmental condition.
Heavy clayey soil and moist shady area with temperature between 20⁰C and 30⁰C are optimal for development of embryo from 10 to 40days. 30

12. Morphology cont….
During development time embryo moults to become infective rhabditiform larva.
When egg contained rhabditiform larva is swallowed infection starts.
Often transmission is through consumption of fresh vegetable grown in night soil.
Can also be transmitted through contaminated drinking water.
Children playing about in mud can transmit eggs through dirty fingers

13. Morphology cont…
In heavily contaminated soil airborne transmission is possible with windswept dust and inhaled then swallowed.
The swallowed eggs reach duodenum, larvae hatch out.
Rhabditiform larvae are actively motile.
They are able to penetrate the intestinal mucosa, enter the portal vessels then carried to the liver.

14. Morphology cont…
They then pass via hepatic vein , inferior vena cava and right heart and reach lungs in four days time.
Being in the lungs they grow and molt twice
From the lungs in about 10-15/7 larvae pierce the lungs capillaries reaching the alveoli
From there got carried up the Resp. to the throat and got swallowed.
Larvae moult and develop into adults in the upper part of small intestine.
They become sexually matured in 6-12/52 and gravid female starts laying eggs then repeat the cycle.
Adult worm has a lifespan of 12-20/12

16. Morphology cont…. A.Lumbricoides egg fertilized mammilated
A.Lubricoides egg unfertilized unmammilated

17. Life cycle

18. Pathogenesis
Clinical features depend on either migrating larvae or adult worms.
The pathogenic effects of larval migration are due to allergic reaction .
The effects larvae exposure normally are asymptomatic except when the load is very heavy.
Re-infection causes intense cellular reaction to migrating larvae in the lungs with infiltration of oesinophils,macrophages and epithelioid cells.

19. Pathogenesis cont…
This type of pneumonia is characterised by low grade fever,dry cough, asthmatic wheezing,urticaria,eosinophilia, and mottled lung infiltration in CXR
Charcot-Leyden crytals,larvae may occassionaly obtained in sputum(Loeffler’s syndrome).
Allergic inflammation to immgrant larvae may involve other organs ie: Kidney or liver rarely in the heart and brain

20. Pathogenesis cont… Manifestations due to adult worms:
Vary from asymptomatic, severe to fatal
Pathological effects present in three pictures (Spoliative action,Toxic action and mechanical)
Spoliative (Nutritional) effects:
These are obvious when worm burden is heavy
In children worms occupy a large part of intestinal tract.
Interfere with absorption and digestion
May lead to Protein-energy malnutrion and Vit A
Patient becomes anorexic also villi become broardened and shortened.

21. Pathogenesis cont…
There is abnormalities of jejunal mucosa ie: elongation of crypts and round cell infiltration of lamina propria these changes are reversible when worms are eliminated.
Toxic effects:
These are due to hypersensitivity to worm antigen and can be presented as: Fever,urticaria,angioneurotic oedema,wheezing and conjuctivitis these symptoms common to patients who get infected by the virtue of their occupations.

22. Pathogenesis cont… Mechanical effects:
These are very important in infection and can be due to:
Masses of worms causing luminal occlusion or single worm infiltrating in vital organ or area.
The adult worms live in upper part of small intestine and can be spanning lumen.
They may stimulate reflex peristalsis causing recurrent and often severe colicky abdomen pains.
When clumped into mass filling lumen leading to volvulus,intussusception or intestinal obstruction.
The worms are very active causing the host silk and male worms are more causative of illness than females.

23. Pathogenesis cont…
The worms do move and may move up to pacreatic duct causing biliary obstruction or pacreatitis
When entering in the liver can cause liver abscess
Can go to oesophagus and come through the mouth and nose.
Can enter trachea leading to respiratory obstruction or lung abscess
Can enter appendix causing obstruction
Can cause peritonitis when perforates the intestines

24. Pathogenesis cont…
Worms go through the Oesophagus and come out through the mouth and nose
Worms clumped to occlude intestinal lumen

25. Clinical features summary.

26. Diagnosis
In early stages during Loeffler’s syndrome larvae can be demonstrated in Sputum or in gastric washing.
Presence of Charcot-Leyden crystals in sputum and Oesinophilia confirm the diagnosis.
Demonstration of an egg in the stool also confirms the diagnosis.
A single female may be responsible for production of 3 eggs in gram of feces
The fertilised egg may seen sometimes decorticated

27. Diagnosis cont….
In light infection eggs are demonstrated by concentration methods
Unfertilised eggs are not demonstrated by salt floatation
Eggs may not seen if there is no male worm
Some occassions worms can be detected by passing worms through mouth ,nose or anus.
Barium contrast radiography of abdomen is also useful in diagnosis.
Serology method is not useful as not reliable

28. Treatment

29. Prevention
Key prevention measure is by prevention of soil contamination.
Proper composting of night manure will ensure killing of resistant eggs produced by worms.
Treatment of vegetables and garden crops with water containing Iodine 200ppm for 15 minutes kills eggs and larvae hence control contamination
Mass deworming campaigns
Proper sanitation infrastructure and utilization

30. (A.duodenale&N.americanus)
Hookworms
(A.duodenale&N.americanus)

31. Hookworms Background: They have been known for many years since 1600BC
Disease caused by the worms is widely distributed in the World(Tropics and Subtropics).
synonyms are:( acanthocheilonemiasis, ancylostomiasis, necatoriasis, and uncinariasis).
900million people worldwide are affected by the disease
Two species known to be human parasites:
(Ancylostoma duodenale and Necator americanus)

32. Background cont… Anklos-hook, stoma-mouth (Greek) Dubin (1843)- Italy
Life cycle was described by Looss in (1898)
-Egypt
Necator americanus was discovered by Stiles (1902)-Texas the name means American murderer
Nacator-Murderer(Latin) this is known as new world while the former as old world hookworm

33. Background cont…
Formerly A.duodenale was predominant in Mediterranean coast of Europe,Africa,Northern India, China and Japan. WHILE
N.Americanus was prevalent in Central and Southern America,Central and Southern Africa,Southern India and Southern Pacific.
But due to movement dynamics there is no difference in distributions any more.

34. Scientific Classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Strongiloidae
Family: Ancylostomatidae
Genus: Necator/Ancylostoma
Species: Necator americanus and Ancylostoma duodenale

35. ANCYLOSTOMA DUODENALE (Ancylostomiasis)
Hookworms
ANCYLOSTOMA DUODENALE (Ancylostomiasis)

36. ANCYLOSTOMA DUODENALE
Morphology:
Adult worm lives in small intestine mostly in Jejunum not common in duodenum.
They are stout cylindrical worms
They are pale pink in colour or greyish white though many look reddish brown due to ingested blood.
Have curved body dorsal aspect concave, ventral convex
Anterior part is constricted and bent dorsally
Cervical curvature derives the name hookworm

37. Morphology cont….. The mouth is located dorsally not at the tip
Has two pairs of hook like teeth ventrally and a dental plate with medium cleft on dorsal aspect.
Male worm :Is about 8-11mm long x0.4mm thick
Posterior end expands into copulatory bursa
It has two long retractile bristle-like copulatory spicules.
Female worm: Is larger10-13mm long x 0.6mm thick.
The hind part is conoid with subterminal anus ventrally

38. Female worm cont… On mating copulatory pair appear Y shaped
The vulva opens ventrally at junction btn middle and posterior 3rd.
On mating copulatory pair appear Y shaped
Eggs:
Are oval or elliptical measuring 60µmx40µm
Colourless with thin transparent hyaline shell membrane.
When released contains unsegmented ovum
When passed in the stool the egg contains segmented ovum
The egg floats on saturated salt solution.
A single female lays 25,000-30,000 a day and million in its life time

39. Morphology
Ancylostoma duodenale

40. A.duodenale egg

41. A.duodenale mouth parts

42. Scientific Classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Strongylida
Family: Ancylostomatidae
Genus: Ancylostoma
Species:A. duodenale
Binomial name: Ancylostoma duodenale

43. Life cycle Humans are the only natural host.
Eggs freshly passed in faeces are not infective
When passed in the soil the embryo develops inside the eggs.
Sand loamy soil with decaying vegetables under moist warm, shade environment is optimum environment for development.

44. Life cycle cont… In 2days a rhabditiform larva hatches out of egg.
Feeds on bacteria and organic materials in the soil.
Grows in size and molt in 3rd to 5th days to become infective Filariform larva.
This is non feeding can live in soil for 5 weeks its head waving in the air waiting for a host can ascend on the blade of grass or vegetation.
(Direct sunlight , drying or salt water can kill the larvae).

45. Life cycle cont…
On barefooted stepping or tourching on soil with filariform they penetrate the skin enter the subcutaneous tissue.
In the subcutaneous tissue larvae enter venules then carried in circulation to right heart then to the lungs.
In the lungs they break out the capillaries to reach the alveoli.
From there they migrate up to respiratory tract to the epiglottis

46. Life cycle cont… From epiglottis they go to pharynx then swallowed.
On reaching the jejunum the develop a temporary buccal capsule by which they get attached to the gut mucosa.
They feed and grow in size and mature into adult.
There is no multiplication in the host takes place each larva develops into single adult (Male or Female).

47. Life cycle cont…
Normally takes 6wks from time of infection to adult worms by which they start laying eggs.
Though in some occasions there may be an arrest in development and process takes longer to 6/12 or more.
Rarely infection may take place through oral route by filariform larvae carried on contaminated vegetables in this case no tissue phase takes place.
Also transplacenta have been reported though not common

48. Life cycle cont… .

49. Epidemiology
It is estimated that million individuals are infected with Hookworm today
Hookworm infection is most concentrated among the world’s poorest who live on less than $2 a day
A. duodenale is found in more scattered focal environments, namely Europe & Mediterranean
Most infected individuals are found in sub-Saharan Africa and East Asia/the Pacific Islands

50. Epidemiology
Other regions are: South Asia, Latin America and the Caribbean, Middle East/North Africa
A majority of infected individuals live in poverty- stricken areas with poor sanitation.
Young school children are mostly infected due to their habits of playing barefooted and eating unproperly washed vegetables

51. Epidemiology map

52. Clinical Presentation
Hookworm infection is generally asymptomatic its damage is “silent and insidious”.
General symptoms include: Ground-itch at the site of parasitic penetration and entry.
Cough and pneumonitis result as the larvae begin to break into the alveoli and travel up the trachea.
Diarrhoea and other gastrointestinal discomfort once the larvae reach the small intestine.

53. Clinical Presentation cont…
Major morbidity caused by hookworm is intestinal blood loss, iron deficiency anemia, and protein malnutrition
Long-term blood loss can manifest itself physically through facial and peripheral edema eosinophilia and pica.
Growth retardation as well as intellectual and cognitive impairments in children.

54. Diagnosis
Diagnostics relies mainly on the recovery of the eggs from the stools.
The egg is unsegmented or in an early segmentation stage when passed.
Because hookworm eggs are often indistinguishable from other parasitic eggs, PCR assays serve as a molecular approach for accurate diagnosis in the feces

55. Management and Therapy
The most common treatment for hookworm are Benzimidazoles ie:Albendazole and Mebendazole

56. Prevention Strategies
Mass deworming campaigns-for school children who are at risk of infection.
Preventative techniques such as: Always wearing shoes, washing your hands before eating, and staying away from water/area contaminated by human feces usage of toilets
Health education, addressing preventive measures that are both feasible and sustainable.

57. NECATOR AMERICANUS (Necatoriasis).
NECATOR AMERICANUS (Necatoriasis)

58. NECATOR AMERICANUS Morphology:
The adult worms are slightly smaller than A.duodenale.
Male measures 7-9mmx 0.3mm while female measuring 9-11mm x 0.4mm.
Anterior end is bent in opposite to general curvature.
Has smaller buccal capsule with two pairs of semilunar cutting plates.
Copulatory bursa of male is wide and long.
Copulatory specules are fused at end to barbed tip

59. Morphology cont…
In female the vulva is located in the mid of the body.
Eggs are identical with A.duodenale
Life cycle is similar to A.duodenale but life span is longer about 4-20yrs in comparison to A.duodenale which is 2-7yrs

60. Morphology cont…

61. Scientific classification
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Strongiloidae
Family: Ancylostomatidae
Genus: Necator/Ancylostoma
Species: Necator americanus

62. Epidemiology
The major etiology of Hookworm infection in Americas, sub-Saharan Africa, and Asia
A majority of infected individuals live in poverty- stricken areas with poor sanitation.
60% infection rate of predominantly N. Americanus
Women have higher prevalence rates than men

63. Pathogenesis and Clin. Features
Clinical features depend on larvae or adult worms
Severe local itching on Filariform larvae entering the skin.
Erythematous papular rashes which turn vesicular leading to scratching the bacterial secondary infection(Ground itch). –This self limited lasting for 2-4wks.
Cutaneous larva migrans may occur
The important manifestations of h/worm infection are caused by adult worms in the intestine

64. Pathogenesis and Clin. Features cont..
The worms attack themselves to the gut mucosa they utilise gut epithelial cells and plasma for their food.
They suck undigested blood and undigested through their intestines
An adult worm can suck 0.2ml blood a day they possess anticoagulant secretions which can lead bleeding to continue from bitten site, hence leading to blood loss.
This can causes microcytic hypochromic type of iron deficiency anaemia

65. Pathogenesis and Clin. Features cont..
The degree and onset of anaemia depend on the intensity of infection , body iron reserve and availability of dietary iron.
H/worm may cause symptoms like those of PU presenting with: Epigastric pain,dyspepsia and vomiting. Also diarrhoea darkish or redish stool.
Severe lassitude and dullness affecting working and learning capacity
Hypoproteinaemia, severe anaemia, generalized puffy oedema can lead to cardiac failure

66. Diagnosis
Demonstration of eggs in stool by direct microscopy or by concentration methods.
Stool sample examined 24hrs or more after collection eggs may have hatches rhabditiform larvae.
Egg count count quantifies the intensity of infection

67. Treatment
Treatment aims at relief of anaemia and getting rid of worm infestation.
So oral iron supplementation is recommended or in severe anaemia(PCV) BT can be transfused.
Getting rid of worms treat as in A.duodenale.

68. Prevention and Control
Prevention of soil pollution with feces
Proper disposal of night soil
Usage of footwear
Usage of gloves during farm works
Proper treatment of patients and carriers at the same time to limit source of infection

69. THANKS FOR LISTENING AND UNDERSTANDING
THE END
THANKS FOR LISTENING AND UNDERSTANDING