Infection Caused by Heliminths

INFECTION CAUSED BY HELMINTHS

1. Nematodes 2. Trematodes 3. Cestodes

INTESTINAL HUMAN NEMATODES

ANCYLOSTOMIASIS (( HOOK WORM ))

ANCYLOSTOMIASIS (( HOOK WORM ))

It is cased by Ancylostoma duodenale or Necator americanus. The adult hookworm is 1 cm length and lives in the duodenum and upper jejunum. eggs are passed in the faeces and in the moist soil,

ANCYLOSTOMIASIS

the larvae develop into the filariform larvae which is the infective stage which penetrate the human skin and carried to the lungs where they ascend to the bronchi are swallowed and mature in the small intestine within 4 – 7 weeks.

PATHOLOGY:

The larvae may cause allergic inflammation at the site of entry in the skin. Heavy infection may cause pulmonary eosinophilia. The worms attach to the small bowel mucosa and withdraw blood (( 0.15 ml/worm/day for A. duodenale )).

The degree of anaemia is variable and it deepened on :

worm load nutritional status iron store.

CLINICAL FEATURES

dermatitis usually on the feet (( ground itch )) paroxysmal cough with blood stained sputum associated with patchy pulmonary consolidation. (( pulmonary phase )). Vomiting and epigastric pain may occur. Iron deficiency anemia, protein losing enteropathy and hypoproteinemia. Cardiac failure may result from chronic iron deficiency

INVESTIGATIONS:

eosinophilia the characteristic ovum can be recognized in the stool. faecal occult blood test will be positive.

MANAGEMANT

mebendazole 100 mg/12 hr. for 3 days or single dose albendazole 400mg. oral iron for treatment of anemia.

ASCARIS LUMBERICOIDES (( ROUND WORM ))

Pale yellow nematode 20 – 35 cm length. Human are infected by eating food contaminated with ova. Ova will hatch in the duodenum to larvae which migrate through the lungs, ascend the bronchial tree, from which they may be swallowed and mature in the small intestine.

CLINICAL FEATURES

variable symptoms from vague abdominal pain to malnutrition obstructive complications: intestinal complications mainly in the terminal ileum or bile duct obstruction.

INVESTIGATIONS;

Diagnosis by demonstration the ova in the faeces Adult warm may be expelled orally or rectally Ba. Meal may demonstrate the adult warm. Eosinophilia

Treatment;

Mebendazole 100 mg/12 hr. for 3 days OR Albendazole 400 mg single dose OR Piperazin 4 gm as single dose For obstructive complications: i.v fluid, nasogastric suction and piprazine.

PREVENTION:

Community chemotherapy regimen OR Treating school age group.

ENTEROBIUS VERMICULARIS(( Thread worm )) (( Pin worm ))

It is common world wide, mainly children, after swallowing of the ova, development take place in the small intestine but the adult worms are found chiefly in the colon.

CLINICAL FEATURES

The gravid female worm lays ova around the anus causing intense itching especially at night, the ova carried to the mouth by the fingers (( auto Re- infection )) Adult worm may be seen moving on the buttocks or in the stool.

INVESTIGATIONS:

Adhesive cellophane tap to the perianal skin in the morning to detect the ova. Perianal swab moistened with saline

TREATMENT

Single dose mebendazole 100 mg OR Albendazole 400mg OR Piperazine 4 gm Treatment may be repeated after 2 weeks. All the family members should be treated. Clothes, bed liven, nail cutting

TREMATODES (( FLUKES ))

Leaf – shaped

SCHISTOSOMIASIS

There are 3 species of the genus Schistosoma causing the disease in human: S. haematobium, S. mansoni & S. japonicum.

SCHISTOSOMIASIS

The ovum is passed in the urine or faeces of the infected individual and gains an access to fresh where the ciliated miracidium iside it will be liberated into the water where it enter the intermediate host (( fresh water snail )) in which it multiply and large number of (( fork – tailed cercaria )) are liberated to the water

SCHISTOSOMIASIS

where they can penetrate the skin or the mucous membrane of the mouth of the human.They transform into SCHISTOSOMUTAE and pass through the lungs and by the blood stream to the liver and so to the portal vein where they mature. Within 4 – 6 weeks, adult worms migrate to the venules draining the pelvic viscera where the females deposit ova.

As for S. haematobium

Pneumonitis, myositis, hepatitis, fever, eosinophilia & seroconversion
weeks
Larval migration & maturation
As for S. haematobium
Papular dermatitis at site of penetration
days
Cercarial penetration
S. mansoni S. japanicum
S. haematobium
time
stage

PATHOGENESIS

Colitis Hepatitis Portal hypertension Ectopic granuloma GN
Cystitis, haematuria ectopic granuloma in the skin, CNS,…Immune complex GN months
Early egg deposition
S. mansoni S. japanicum
S. haematobium
time
stage

PATHOGENESIS

Colonic polyposis & stricture Periportal fibrosis Portal hypertension Pulmonary granuloma & pulmonary hypertension
Fibrosis & calcification of ureters and bladder Bacterial infection Calculi Hydronephrosis Carcinoma Pulmonary granuloma & pulmonary hypertension
years
Late egg deposition
S. mansoni S. japanicum
S. haematobium
time
stage

PATHOGENESIS

CLINICAL FEATURES

Itching lasting 1 – 2 days at the site of cercarial penetration.After symptom free – period of 3 – 5 weeks, acute Schistosomiasis (( Katayama syndrome )) such as urticaria, fever, muscle aches,

CLINICAL FEATURES

abdominal pain, headache, cough, sweating, hepatosplenomegaly, lymphadenopathy and pneumonia may be present and there is eosinophelia Katayama syndrome seen in severe S.mansoni and S. japanicum but rare in S. haematobium.

CLINICAL FEATURES

Acute Schistosomiasis subside after 1 – 2 weeks.Chronic Schistosomiasis due to egg deposition depend upon the intensity of the infection and the species

S. haematobium

Painless terminal haematuria Frequency due to bladder calcification Frequent UTI Bladder or ureteric stone formation Hydronephrosis Renal impairment & renal failure with contracted calcified bladder

S. haematobium

Loin pain radiated to the groin Haemospermia Intestinal symptoms may follow bowel wall involemant Strong association with squamous cell carcinoma of the bladder.

S. mansoni

Variable symptoms from malaise, abdominal pain, frequent blood – stained diarrhea & rectal polypsPortal hypertension may cause massive splenomegaly

S. mansoni

Fatal haematemesis from esophageal varices or progressive ascites. Liver function is initially preserved because the pathology is fibrotic rather than cirrhotic. S. mansoni infection predispose to the carriage of salmonella.

S. japanicum

The adult worm infect human, dogs, rats, cats, pigs & sheeps. The pathology is similar to that of S. mansoni but but it produces more eggs and extensive & wide spread lesions The clinical features resemble severe infection with S. mansoni with added neurological features. Small as well as the large bowel may be affected.

INVESTIGATIONS:

Demonistration of eggs or serological evidence of the infection.S. haematobium → terminal spined egg.S. mansoni → lateral spined egg.S. japanicum → lateral rudimentary spined egg.

INVESTIGATIONS

Ultrasonagraphy may shows bladder wall thickening and calicification with or without hydronephrosis. Cystoscopy may shows sandy patches, bleeding mucosa & later distortion.

INVESTIGATIONS

Sigmoidoscopy may shows inflammation and bleeding with biopsy for ova in S. mansoni and S. japanicum. Eosinophelia. Serology via ELISA as a screening test.

TREATMANT:

Praziquantel 40 mg/kg once is the drug of choice for all forms of Schistosomiasis produce 80% cure & 90% reduction in egg counts in the remaining. S/E nausea and abdominal pain Oxamniquine is useful and safe in chronic hepatic forms of S. mansoni

TREATMANT

Surgery may be required for residual lesions. Plastic surgery for uretric stricture and fibrotic lesions Removal of rectal papilloma by diathermy.

PREVENTION:

the life cycle is terminated if the ova in urine or faeces are not allowed to contaminate fresh water containing the snail host. mass treatment of the population. attack on the intermediate host (( the snail ))

CESTODES (( TAPEWORMS ))

they inhibit intestinal tract they have no alimentary system and absorb nutrient through there surface. The anterior surface (( scolex )) has suckers for attachment to the host. From the scolex, a series of progressively developing segments are arises.

CESTODES (( TAPEWORMS ))

Larvae are librated from ingested ova.Human acquired the infection by eating undercooked beef infected with cysticercus bovis (( the larval stage of Taenia Saginata – beef tapeworm-)).

CESTODES (( TAPEWORMS ))

Undercooked pork containing larval stage of T. Solium (( pork tapeworm)) Undercooked fresh water fish containg larva of Diphillobothrium latum (( fish tapeworm )) Usually only one adult tapeworm is present in the gut but up to ten have been detected.

TAENIA SAGINATA

Adult worm may be several meters length and produce little or no intestinal upset in human being. Ova may be found in the stool which is indistinguishable fro T. solium ova.

TAENIA SAGINATA

Praziquantel is the drug of choice Niclosamide is an alternative. Prevention depend on efficient meat inspection and through good cooking of beef

TAENIA SOLIUM

It is not as large as T. saginata. The adult worm is found only in human following the eating of undercooked pork containing cysticerci

CYSTICERCOSIS:

It is acquired by ingestion of tapeworm ova from contaminated fingers or by eating contaminated food. The larvae are librated from eggs in the stomach and then penetrate the intestinal mucosa and carried to many parts of the body

CYSTICERCOSIS:

where they developed and form CYSTISERCI ( 0.5 – 1 cm cysts that contain the head of a young worm ). They do not grow or migrate & located in subcutaneous tissues, skeletal muscles and brain.

CLINICAL FEATURES:

Cysts can be palpated under the skin or mucosa, they may cause few or no symptoms and will die & become calcified. Heavy brain infection may cause features of encephalitis

CLINICAL FEATURES:

Cerebral signs do not occur until the larvae die, 5 – 20 years later in form of epilepsy or personality disorders.Abnormal gait or signs of internal hydrocephalus.

INVESTIGATIONS

calcified cyst can be recognized radiologicaly brain CT or MRI are more sensitive epileptic fit starting in adult life in endemic area suggest the diagnosis antibody detection by IFAT

TREATMANT

intestinal infection ; Niclosamide followed by mild laxative for cerebral cystisercosis, praziquantel improve prognosis albendazole for parenchymal neurocystisercosis

TREATMANT

prednisolone given 1 day before praziquantel or allbendazole antiepileptic drugs should be given surgery for hydrocephalus

ECHINOCOCCUS GRANULOSUSTAENIA ECHINOCOCCUS

HYDATID DISEASE



dogs are the definitive host the larval stage ( hydatid cyst ) normally occurs in sheep, cattle, camels and other animals. By handling the dog or drinking contaminated water, human may ingest the eggs &

HYDATID DISEASE

the embryo will liberated in the small intestine and then to the blood stream and then to the liver. The resultant cyst will grow very slowly & it may be calcified or rupture giving rise to multiple cysts.

CLINICAL FEATURES

It typically acquired during childhood Usually symptomless. It may cause pressure symptoms

CLINICAL FEATURES

In 75% of patients with hydatid disease, the right lobe of the liver is involved and contain a single cyst. In the others single or multiple cysts may be found in the lungs, liver, bone, brain or elsewhere.

INVESTIGATIONS:

Clinical Radiological Ultrasound finding Complement fixation ELISA

TREATMANT:

hydatid cyst should be excised wherever possible. albendazole 400mg/12hr for 3 months used for inoperable or multiple cysts and to reduce the infectivity of the cyst preoperatively. praziquantel 20 mg/ kg/12hr. for 14 days kill protoscolices perioperativly.

GOOD LUCK

GOOD BYE