Schistosomiasis
Description
• Schistosomiasis is an acute or chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma.
• Infection larval forms of the parasite released by freshwater snails penetrate the skin during contact with infested water.
There are 2 major forms of schistosomiasis that are caused by 5 main species of blood fluke:
• Intestinal: Schistosoma mansoni, Schistosoma japonicum, Schistosoma mekongi and Schistosoma
intercalatum
• Urogenital: Schistosoma haematobium.
Signs and Symptoms
In the acute infection, mild, maculopapular skin lesions may develop within hours after exposure.
• Intestinal schistosomiasis
o Acute: Abdominal pain, diarrhoea, blood in the stool, fatigue.
o Chronic: hepatomegaly, splenomegaly ascites, portal, and pulmonary hypertension.
• Urogenital Schistosomiasis
o Acute: Haematuria, dysuria, urinary frequency.
o Chronic: Fibrosis of the bladder and ureter, kidney dysfunction, bladder cancer (later stages).
o Adolescent girls: genital lesions, vaginal bleeding, dyspaurenia nodules in the vulva.
o Adolescent boys: pathology of the seminal vesicles, prostate, and other organs
Investigations
• Stool/Urine M/C/S for blood and Schistosoma ova.
• FBC, DC-Eosinophilia.
• Urea, Electrolytes, LFTs.
• Chest x-ray
• Plain abdominal x rays
• Abdominal ultrasound
• Blood culture
• Rectal Snip
Treatment
• Praziquantel is the treatment of choice for all forms of Schistosomiasis (children >2 years and adults:
40mg/kg as a single dose). Consider steroid therapy if very severe disease.
• Adverse effects of praziquantel include dizziness, headache, nausea, vomiting, diarrhea, abdominal
discomfort, bloody stool, urticaria, and fever following initiation of treatment. These are usually mild and
last about 24 hours.
• Prevention: Praziquantel 40/mg/kg as a single dose.
Taeniasis/Cystercercosis
Description
Intestinal infection with tapeworm acquired from eating raw or not-well cooked food. Causative organisms include; 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 infection of tissues with larval parasites (Cysticercosis). The larvae (cysticerci) are most often located in subcutaneous and intramuscular tissue, followed by the eye and brain. The CNS is involved in 60-90% of patients resulting in neurocystercosis.
Signs and Symptoms
Taeniasis
• Colicky abdominal pain
• Body Weakness
• Loss of or increased appetite
• Constipation or diarrhea
• Pruritus ani or hyperexcitability
Neurocystersercosis
• Seizures
• Intracranial hypertension: Headache, nausea, vomiting, vertigo, and papilledema.
• Personality and mental status changes (Neuropsychiatric changes).
• Behavioural changes and learning disabilities.
Investigations
• Stool M/C/S- Evidence of characteristic ova, proglottides or scolex in the wet mount stool examination
tissues.
• Brain CT scan or MRI
NB: Refer the patient to high centers for further investigation and expertise
Treatment
Taeniasis A: Praziquansstel (PO) 5–10mg/kg single dose.
• Neurocystercercosis: Albendazole 15mg/kg/day for 15 days in 2 divided doses plus corticosteroids-
prednisolone 1-2mg/kg/day or dexamethasone
• Praziquantel 50mg/kg /day for 15 days
• Surgical removal of cysts depending on site of infection e.g eyes, spine, or subcutaneous tissue.
Albendazole or praziquantel should not be used to treat ocular or spine cysts as resulting inflammation may cause permanent damage.
Further treatment:
• Anti-epileptic drugs if seizure occur. Carbamazepine, phenobarbitone or sodium valproate. Treatment is
recommeded until the patient has been seizure free for 2 years.
• Osmotic diuretics for Intracranial hypertension.
• Ventricle- peritoneal shunt placement for hydrocephalus.