Helminth infestation

Signs and Symptoms

Adult worms are found in the lymphatics and lymph nodes. Larvae grow and mature in the regional lymph nodes for up to 18 months. The patient then presents with:

• Fever ranging from 39°C - 41°C
• Lymphangitis, both of which subside in 3 - 5 days.
• Red streaks on the skin, are tender and cord-like.
• Involvement of the lymphatics of the epididymis, testes and spermatic cord causing obstruction which presents with oedema of the lower limbs and scrota.
• Long-standing oedema produces thick, rough skin which may ulcerate

Treatment

• Diethylcarbamazine 2 – 6mg/kg daily in divided doses for 2 – 3 weeks. The course is repeated after 6 weeks.
• Supportive care is antihistamines or steroids for allergic reactions that can occur.
• Also associated bacterial infections should be treated and reconstructive surgery can be done on unsightly tissue.

Complications

Tropical eosinophilia is characterized by:

• Lymphadenopathy
• Splenomegaly
• Cough
• Bronchospasm and asthma-like picture

Signs and Symptoms

Caused by adult worms which prefer the sub conjunctival and periorbital tissues. The main features are:

• Calabar swellings – painless, localised, transient, hot soft tissue swellings often near joints lasting from a few hours to several weeks
• Urticaria
• Pruritis
• Lymphoedema, ahritis and chorioretinitis may occur
• A meningoencephalitis like picture may occur during treatment

Treatment

• Diethylcarbamazine, 2 - 6mg/kg daily for 2 - 3 weeks

Signs and Symptoms

The incubation period averages 1 year

• Initially, a papular, reddish, itchy rash occur
• After repeated infection subcutaneous nodules develop associated with genital elephantiasis, hydrocele and ocular lesions. Ocular lesions are serious and may cause blindness
• Initially, there is excessive tear production, photophobia and the sensation of a foreign body in the eye
• Then conjunctivitis, iridocyclitis, chorioretinitis, secondary glaucoma and optic atrophy may occur.

Treatment

• Ivermectin 150mcg/kg orally as a single dose. Annual retreatment must be given until adult worms die.
• In endemic areas not all patients need treatment. Indications for treatment are the threat of eye damage and severe pruritis.

Prevention

• Primary prevention is aimed at vector control and protection of humans from vectors.
• Mass chemotherapy with Diethylcarbamazine is effective in bancroftian filariasis and loasis.

Description

It is a small intestinal infestation caused by Ascaris lumbricoides which leads to malnutrition, iron deficiency anaemia, impaired growth and cognition in susceptible hosts. It is most common infestation in children and it is acquired through ingestion of contaminated food and water. Infection is acquired by ingesting contaminated food

Signs and Symptoms

• Chronic Diarrhea
  • Nausea
  • Vomiting
  • Abdominal discomfort
  • Anorexia
• Steatorrhea
• Malnutrition
• Chronic Cough (loffers’s syndrome)
• Intestinal obstruction
• Obstructive jaundice

Investigations

Wet mount stool examination (Evidence of ova or worms)

Treatment

• Mebendazole (PO) 500mg as a single dose or 100mg 12 hourly for 3 days.
OR
• Albendazole (PO) 400mg as a single dose.

Description

Infestation occurs by penetration of the skin by larvae. This can lead to life-threatening infestation and disseminated strongyloidiasis in an immune-compromised host

Signs and Symptoms

• Pruritic papulo–vesicular rash at the site of penetration or uticarial rash involving the perennial region extending to the buttocks, thighs and abdomen
• Chronic cough
• Colicky abdominal pains
• Chronic diarrhea and passage of mucus
• Weight loss
• Hyper-infection syndrome

Investigations

• Wet mount stool examination (Evidence of rhabiditform larva)
• ELISA for anti-strongyloides antibody

Treatment

• Mebendazole (PO) 500mg as a single dose or 100mg 12 hourly for 3 days.
OR
• Albendazole (PO) 400mg as a single dose.
OR
• Ivermectin (PO) 200 μg /kg daily for 2 days
OR
• Thiabendazole (PO) 25mg/kg body weight (max.1.5g) 12 hourly for 3 days

Note: Give treatment for 10 days in case of disseminated/super infestation

Description

It is a hookworm disease caused by infestation of the small intestine with Ancylostoma duodenale or Necator americanus leading to anaemia and malnutrition

Signs and Symptoms

• Abdominal pains
• Chronic diarrhoea
• Melena stool
• Weight loss
• Chronic cough (loafers’ syndrome)
• Anaemia

Investigations

• Wet mount stool examination (Evidence of ova or worms)
• FBC

Treatment

• Mebendazole (PO) 500mg as a single dose or 100mg 12 hourly for 3 days.
OR
• Albendazole (PO) 400mg as a single dose.

Note:

• If it persists, give second course after 4 weeks.
• Iron replacement and nutritional supplementation (protein and vitamins) should be part of the management strategy.

NB: Albendazole is contraindicated in the first trimester of pregnancy

Most infestations are asymptomatic.

Signs and Symptoms

Heavy infestation is associated with:

• Bloody diarrhoea and mucus
• Abdominal discomfort
• Anorexia and weight loss.
• Appendicitis
• Rectal prolapse (mostly in children)

Treatment

Mebendazole 100mg twice daily for 3 days.

Description

Intense anal pruritis which is usually nocturnal. Scratching results in dissemination of eggs

Treatment

A single dose of Mebendazole 500mg followed by a second dose 2 weeks later. Family members should also be treated.

Prevention

• Personal hygiene
• Proper sanitation

Description

Taeniasis
Can be due to Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), Diphyllobothrium latum (fish tapeworm) and Hymenolepsis nana (faecal oral contamination from human and dogs) leading to chronic malnutrition (Taeniasis) or multi-organ dissemination and dysfunction (Cysticercosis)

Cysticercosis
The cysticerci are most often located in subcutaneous and intermuscular tissues, followed by the eye and then the brain. The CNS is involved in 60-90% of patients i.e. Neurocystercosis

Signs and Symptoms

Taeniasis

• Colicky abdominal pain
• Body Weakness
• Loss of or increased appetite
• Constipation or diarrhea
• Pruritus ani
• Hyperexcitability

Cysticercosis

• Convulsions and/or seizures
• Intracranial hypertension: headache, nausea, vomiting, vertigo, and papilledema.
• Personality and mental status changes (Neuropsychiatric changes)
• Behavioural changes and learning disabilities more marked in children and immunocompromised adults.

Investigations

• Taeniasis
  • Wet mount stool (Evidence of characteristic ova, proglottides or scolex)
• Cysticercosis
  • CT scan

NB: Refer the patient to high centres for further investigation and expertise

Treatment

Taeniasis

• Praziquantel (PO) 5–10mg/kg single dose

        OR

• Niclosamide (PO) 2g as a single dose after a light breakfast followed

        AND

• Magnesium sulphate 5–10 g in a glass of water after 2 hours

Cysticercosis

• Praziquantel 50mg/kg/day for 21 days

        OR

• Albendazole 15mg/kg/day for

        AND

• Dexamethasone IV 4mg hourly can be given up to

        AND

• Carbamazepine initially 200 mg 1–2 times daily, increased slowly to 8–1.2g daily in divided doses

Note:

• Hydrocephalus should be treated with surgical
• Ocular manifestation cysticercosis, should be referred to eye specialist

Prevention

• Careful inspection of beef or pork for cysticerci (encysted larval forms)
• Refrigeration of beef at -10°C for 5 days or cooking at 57°C for at least 30 minutes.

Schistosomiasis (Bilharziasis)

Description

Parasitic disease caused by blood flukes (trematodes) of the genus Schistosoma. Most common species in Zambia are Schistosoma haematobium in urine and Schistosoma mansoni in stool responsible for intestinal schistosomiasis as a result of immune mediated reaction which leads to progressive inflammation and fibrosis of the urinary bladder or portal venous system respectively

Signs and Symptoms

Schistosoma mansoni:

• Swimmer’s itch or katayama fevers in acute infection phase.
• Colicky abdominal pains
• Diarrhoea and dysentery
• Anemia
• Hepatomegally
• Portal hypertension with bleeding esophageal varices or
• Decompensated liver disease

Schistosoma hematobium:

• Dysuria and terminal hematuria
• Hematospermia
• Obstructive uropathy (hydronephrosis, hydroureters)
• Glomerulonephritis and amyloidosis
• Bladder carcinoma
• Chronic kidney failure

Investigations

Laboratory evidence characteristic eggs:

• In urine, (S. Hematobium)
• In stool (S.manson, S.japonicum) examined by kato katz thick smear procedure
• PCR assays of both urine and stool samples

Treatment

Praziquantel (PO) 40mg/kg as a single dose or in 2 divided doses

Prevention

• Use of latrines, preventing children from playing in infected water
• Using water from a protected well or boiling for at least 10 minutes

Description

It is the infestation of the upper small intestine caused by the flagellate protozoan Giardia Lamblia (or G. intestinalis), cytopathic effects of which leads to malabsorption and diarrhoea. Spread is faecal-oral and person to person. The infective form is the cyst.

Signs and Symptoms

• Crampy abdominal pain
• Chronic diarrhoea
• Steatorrhea
• Weight loss

Investigations

• Serial 3 samples of stool examination (Evidence of Giardia intestinalis trophozoites or cysts)

        OR

• Serological evidence of Intestinalis trophozites antigen or antibody

       OR

• Evidence of G. Intestinalis in duodenal aspirates or biopsy specimen.

Treatment

• Metronidazole (PO) 400–800mg 8 hourly for 5 days OR 2g Stat

        OR

• Tinidazole (PO) 2g once daily for 3 days

        OR

• Secnidazole (PO) 2g single dose

Prevention

• Personal hygiene
• Improvement of water safety by either boiling it for at least 10 minutes or correctly chlorinating

Complications

Growth retardation in children.

References

• Cunha, BA, Pneumonia 3rd Edition. Royal Oak Michigan. Physicians Press; 2010