10.1.1 Amoebiasis
Amoebiasis is an infection caused by the protozoa organism Entamoeba histolytica, which can cause colitis and other extra-intestinal manifestations. The infection is primarily acquired through ingestion of contaminated food and water and occasionally can be acquired through oral-anal sexual practices.
Diagnostic Criteria
- Bloody diarrhea
- Crampy abdominal pain
- Fever
- Weight loss
- Peritonitis in severe forms
- Evidence of motile trophozoites or cysts on saline wet mount from a stool specimen
Pharmacological Treatment
A: Metronidazole (PO) 400–800mg 8 hourly for 5 days
OR
B: Tinidazole (PO) 2g once daily for 3 days
OR
C: Secnidazole (PO) 2g single dose
10.1.2 Amoebic Liver Abscess
It is the most frequent extra-intestinal manifestation of Entamoeba histolytica infection which results from the invasion of the portal venous system from the colon leading to inflammation and subsequently abscess formation particularly involving the right lobe of the liver.
Diagnostic Criteria
- High grade fever
- Right upper quadrant pain,
- Tender and enlarged liver
- Positive imaging evidence of liver abscess
AND - Serological evidence of histolytica antibodies or antigens.
Pharmacological Treatment
C: Metronidazole IV 800 mg, 8 hourly for 10 days.
OR
B: Tinidazole (PO). Adults: 2g once daily for 3 days
Note: | |
| Metronidazole, Tinidazole, and Secnidazole should not be given in the first trimester of pregnancy due to potential teratogenic effects. |
| Should not be taken with alcohol due to disulfiram like effects |
Surgery:
Abscess cavity (size >5 cm in diameter) not regressing despite 7 days treatment should be aspirated.
10.1.3. Giardiasis
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 diarrhea. It is more common in immune compromised individuals and is acquired through ingestion of contaminated water
Diagnostic Criteria
- Crampy abdominal pain
- Chronic diarrhoea
- Steatorrhea
- Weight loss PLUS
Evidence of Giardia intestinalis trophozoites or cysts on serial 3 samples of stool examination
OR
Serological evidence of G. Intestinalis trophozites antigen or antibody
OR
Evidence of G.Intestinalis in duodenal aspirates or biopsy specimen.
Pharmacological Treatment
A: Metronidazole (PO) 400–800mg 8 hourly for 5 days
OR
B: Tinidazole (PO) 2g once daily for 3 days
OR
C: Secnidazole (PO) 2g single dose
10.1.4 Ascariasis
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.
Diagnostic Criteria
- Chronic Diarrhea
- Steatorrhea
- Malnutrition
- Chronic Cough (loffers’s syndrome)
- Intestinal obstruction
- Obstructive jaundice PLUS
- Evidence of ova or worms on wet mount stool examination
Pharmacological Treatment
A: Mebendazole (PO) 500mg as a single dose or 100mg 12 hourly for 3 days.
OR
A: Albendazole (PO) 400mg as a single dose.
10.1.5 Ancylostomiasis
It is a hookworm disease caused by infestation of the small intestine with Ancylostoma duodenale or Necator americanus leading to anaemia and malnutrition.
Diagnostic Criteria
- Abdominal pains
- Chronic diarrhea
- Melena stool
- Weight loss
- Chronic cough ( loafers’ syndrome) PLUS
- Evidence of ova or worms on wet mount stool examination
- Anaemia
Pharmacological Treatment
A: Mebendazole (PO) 500mg as a single dose or 100mg 12 hourly for 3 days.
OR
A: Albendazole (PO) 400mg as a single dose.
Note: | |
| If persist, give second course after 4 weeks. |
| Iron replacement and nutritional supplementation (protein and vitamins) should be part of the management strategy. |
| Albendazole is contraindicated in the first trimester of pregnancy |
10.1.6 Strongyloidiasis
Small intestinal infestation caused by Strongyloides stercoralis usually asymptomatic in immune competent adult but can lead to life-threatening infestation and disseminated strongyloidiasis in an immune-compromised host associated with high mortality rates
Diagnostic Criteria
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 PLUS
- Evidence of rhabiditform larva in wet mount stool examination with Serological evidence (ELISA) for anti-strongyloides antibody
Pharmacological Treatment
A: Albendazole (PO) 400mg 12 hourly for 3 days (Repeat after 4 weeks if still positive stool findings)
OR
A: Ivermectin (PO) 200 µg /kg daily for 2 days
OR
A: 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
10.1.7 Taeniasis
Is a tapeworm disease acquired from eating raw or not-well cooked food. 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)
Diagnostic Criteria
Taeniasis
- Colicky abdominal pain
- Body Weakness
- Loss of or increased appetite
- Constipation or diarrhea
- Pruritus ani
- Hyperexcitability PLUS
- Evidence of characteristic ova, proglottides or scolex in the wet mount stool examination
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 which may manifest as
- 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. PLUS
- CT scan
NB: Refer the patient to high centres for further investigation and expertise.
Pharmacological Treatment
Taeniasis
A: Praziquantel (PO) 5–10mg/kg single dose
OR
C: Niclosamide (PO) 2g as a single dose after a light breakfast followed
AND
D: Magnesium sulphate 5–10 g in a glass of water after 2 hours
Cysticercosis (NCC)
A: Praziquantel 50mg/kg/day for 21 days
OR
A: Albendazole 15mg/kg/day for 30days.
AND
B: Dexamethasone IV 4mg hourly can be given up to 7days.
AND
A: Carbamazepine initially 200 mg 1–2 times daily, increased slowly to 0.8–1.2 g daily in divided doses
Note:
- Hydrocephalus should be treated with surgical shutting.
- Ocular manifestation cysticercosis, should be referred to eye specialist
10.1.8 Echinococcosis
It is a canine tape worm Echinococcus Granulosus which is transmitted by dogs, sheeps and horses. Human infestation is through contamination of food or water causing visceral cysts (Hydatid Cyst Disease) particularly in the liver and lungs and is usually asymptomatic in susceptible host.
Diagnostic Criteria
- Upper abdominal discomfort and pain, poor appetite, Upper abdominal mass swelling with enlarged liver.
- Cough with features of acute hypersensitivity reaction. ( for ruptured cysts)
- Portal hypertension, Biliary obstruction or Budd-Chiari syndrome (for complicated cases)
Pharmacological Treatment
A: Albendazole (PO) 400mg 12 hourly for 3 months OR
A: Mebendazole 500mg for 3 months
Surgery:
For symptomatic/ complicated cases refer to higher centres with management and expertise.
10.1.9 Schistosomiasis
Parasitic disease caused by blood flukes (trematodes) of the genus Schistosoma. Common species found in Tanzania are S. haematobium responsible for urogenital schistosomisis and S. mansoni 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.
Diagnostic Criteria
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 amylodosis
- Bladder carcinoma
- Chronic kidney failure PLUS
- Laboratory evidence characteristic eggs in urine, ( Hematobium) or in stool (S .manson, S.japonicum) examined by kato katz thick smear procedure or PCR assays of both urine and stool samples.5
Pharmacological Treatment
A: Praziquantel (PO) 40mg/kg as a single dose or in 2 divided doses
10.1.10 Typhoid and Paratyphoid
It is an acute systemic disease resulting from infection by Salmonella typhi and S.paratyphi, serovar group A and B respectively. Infection is acquired through ingestion of contaminated food and water.
Diagnostic Criteria
- Fever, severe headache, abdominal and muscle pains (myalgia)
- Delirium, obtundation, intestinal hemorrhage, bowel perforation,
- Sequela neuropsychiatric complications Plus
- Laboratory evidence of positive cultures from bone marrow aspirates; blood or stool done within 1 week of acute infection OR
- Serological evidence of rising high titers above 1:160 (Widal test), OR
- Indirect fluorescent Vi antibody, ELISA for immunoglobulin M (IgM) and IgG antibodies to Typhi polysaccharide.
Pharmacological Treatment
A: Ciprofloxacin (PO) 500mg 12 hourly for 10 days
OR
B: Azithromycin (PO) Adult 500mg for 7 days
10.1.11 Shigellosis
Shigella organisms are a group of gram-negative, facultative intracellular bacteria pathogens. They are grouped into 4 species: Shigella dysenteriae, Shigella flexneri, Shigella boydii, and Shigella sonnei, also known as groups A, B, C, and D respectively. Shigellosis is spread by means of fecal-oral, by igestion by ingestion of contaminated food or water and leads to bacillary dysentery.
Diagnostic Criteria
- Acute abdominal cramping, high-grade fever, emesis and large-volume watery diarrhea
- Tenesmus, urgency, fecal incontinence, mucoid bloody diarrhea
- Severe headache, lethargy, meningismus, delirium, and convulsions
- Hemolytic uremic syndrome (HUS), microangiopathic hemolytic anemia, thrombocytopenia, and renal failure
- Profound dehydration and hypoglycemia PLUS
- Laboratory evidence of microscopic isolation of the bacteria from stool or rectal swabs specimens
OR - Stool culture for suspected cases in early course of infection
OR - An enzyme immunoassay (ELISA) for shiga toxin detection in stool for dysenteriae type-1.
Pharmacological Treatment
A: Ciprofloxacin (PO) 500mg 12 hourly for 5 days
OR
C: Nalidixic acid (PO) 1000mg 6 hourly for 7 days
OR
A: Erythromycin (PO) 250mg 6 hourly for 5 days.
10.1.12 Cholera
For diagnostic criteria, investigations, preventation and treatment refer to section 4.1 under notifiable diseases.