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These are small creatures (animals) which invade and infect (infest) the body. They may be either:
Children with AIDS may be infected with unusual parasites not normally seen in healthy children (e.g. Toxoplasmosis).
In Southern Africa the common intestinal parasites are:
Roundworms are the most common parasites found in the gut of children. The worms are pink and smooth and measure about 25 cm long. They look like pale garden earth worms.
Roundworms produce thousands of eggs a day which are passed in the child’s stool (faeces). The eggs have a very characteristic shape and can be easily recognised if a sample of stool is examined under a microscope.
Roundworms are common in children between the ages of 1 and 5 years.
Roundworms are the most common bowel parasite in many poor countries.
If human faeces are not disposed of in a hygienic way, or if sewerage sludge is used as a garden fertiliser, children can swallow and get infected by roundworm eggs. Roundworm eggs can survive in soil for years. Playing or crawling in contaminated soil or eating raw vegetables that have not been washed may result in infection. High prevalence rates are common in communities with poor sanitation. This is a major public health problem in many parts of South Africa.
Roundworm eggs hatch in the child’s small bowel, and the newly hatched larvae then pass through the bowel wall into the bloodstream and are carried to the alveoli of the lungs. From here they make their way up the bronchi and trachea then get swallowed. In the small bowel the roundworm larvae mature into adult worms where they can live for 2 years.
Many children with roundworms appear healthy and have no symptoms. Often the only way the parents know that their children have roundworms, is when worms are seen in the stool. Sometimes worms can be vomited. When the child is ill with a fever, roundworms may make their way up the child’s oesophagus and come out of the nose.
Large numbers of worms in the bowel can cause problems:
The larvae (which hatch out of the eggs in the gut) can causes respiratory symptoms and signs during the time that they are migrating through the lungs. Children with roundworm larvae in the lungs present with a dry cough or wheeze.
Roundworm infection can be treated with either of:
Deworming every 6 months is recommended for children between the ages of 2 and 5 years in communities with poor hygiene and inadequate sanitation (poor toilet facilities). This should be done even if there is no history of roundworms in the stool. Medication is usually given at the local primary care clinic or in schools. Deworming has been found to improve the learning capacity and growth of school children.
Mebendazole is the drug of choice. Albendazole is more expensive. The dose for deworming is the same as for treating roundworms. Both these drugs are highly effective for roundworms.
Regular deworming of young children is recommended in communities where roundworms are common.
Whipworms commonly infect the bowel of children in Southern Africa. They are short, thin worms (about 4 cm) that attach themselves to the mucosa of the large bowel where they cause bleeding. It is rare to see the worms in the stool.
As with roundworms, eggs are ingested (swallowed) with soil. The eggs hatch in the child’s gut and the larvae attach to the bowel wall. Unlike roundworms, the larvae do not migrate through the lungs.
Whipworms usually infect children over 5 years of age. If the infection is light there are usually no symptoms or signs. Heavy infection can cause:
Whipworm infection can cause iron deficiency anaemia.
Pinworm infection is very common. They are small, thin worms (about 4 cm long). Pinworms are especially common where children sleep or play together in crowded conditions. Adult female worms pass out the anus at night to lay eggs on the perineum. Eggs are swallowed from contaminated fingers, clothing or bed linen. Pinworms are common even where hygiene and sanitation are of a high standard. They are also known as threadworms.
Perianal itching and scratching at night. This may cause loss of sleep. Secondary infection of the scratched skin is common. In girls the worms may enter the vulva causing irritation and vaginal discharge (vaginitis).
Pinworm infection presents with perianal itching and scratching, especially at night.
The clinical diagnosis can be confirmed by the parent finding the small worms on the skin around the anus at night. A piece of sticky tape (Sellotape) should be placed against the anus and surrounding skin during the night and then immediately removed. In this way eggs can be collected and identified under a microscope.
Mebendazole or albendazole, as used for roundworms
Hookworms commonly occur in warm, moist climates such as northern KwaZulu-Natal and the Mozambique coast. With poor sanitation, hookworm eggs in the stool contaminate the soil and hatch rapidly. They then infect the feet of barefoot children. Once the skin is penetrated, hookworms behave like roundworms as they enter the bloodstream and travel via the lungs to get into the small bowel. The worms attach to the bowel mucosa and cause bleeding.
Usually, there are no symptoms unless there is heavy infection. The child may have an unusually large appetite and want to eat sand. In severe cases there may be signs of iron deficiency anaemia.
Worms and their eggs may be found in the stools.
Mebendazole or albendazole, as for roundworm infection.
The common tapeworms that infect the human gut are the pork and, to a lesser degree, the beef tapeworm. They are very long (up to 5 metres) segmented worms that grow in the small bowel of humans after eating uncooked or partially cooked meat, which is contaminated with tapeworm cysts. Tapeworm segments filled with eggs are excreted in human stools and later may be swallowed by animals (pigs or cows). The eggs hatch in the animal’s gut and are carried in the bloodstream to the muscles of the animals where they become tapeworm cysts. Eating infected, uncooked meat of these animals completes the life cycle of the tapeworm when the eggs hatch, resulting in adult worms living in the human gut.
Most tapeworms result from eating poorly cooked pork which is infected with tapeworm cysts.
Small segments of the worm are seen in the stool or may be found in the bed. Often there are no other symptoms. However, tapeworms can cause abdominal discomfort, failure to thrive and loss of appetite.
Mebendazole orally 100 mg twice daily for 7 days.
If possible, animals should be slaughtered in a registered abattoir where all meat is inspected to ensure that it is not infected by tapeworm cysts. Cooking meat well kills the cysts. Therefore, avoid eating raw or partially cooked meat. Meat lightly cooked on an open fire may still contain live tapeworm cysts.
Human stools must be disposed of safely so that it cannot be eaten by pigs. This will prevent the pigs from becoming infected with tapeworm cysts. Parts of the Eastern Cape of South Africa are particularly heavily contaminated with tapeworm eggs.
In villages, pigs must be prevented from eating human faeces.
Yes. Sometimes the eggs of the pork tapeworm, which have been passed in human faeces, are swallowed by other humans (instead of by pigs) in food or water contaminated by infected human faeces. The eggs hatch in the child’s gut and are then carried by the bloodstream into all parts of the body including the brain. In the brain they form many small tape worm cysts (neurocysticercosis) which cause fits (convulsions). Tapeworm cysts in the brain are a common cause of fits in children that live in rural areas where toilets are not available. Good sanitation, safe water, hand-washing and washed vegetables will reduce the risk of neurocysticercosis.
Swallowed pork tapeworm eggs from human faeces result in tapeworm cysts in the brain.
This is caused by the dog tapeworm which can occur in the gut of dogs. Eggs, which are passed in the dog’s stool, may be swallowed by sheep and goats, resulting in tapeworm cysts in their muscles. Other dogs can then be infected with tapeworms by eating the raw meat of these sheep or goats.
If eggs of the dog tapeworm are swallowed by humans instead, the eggs hatch in the human gut and are carried by the bloodstream to the liver or lung where they form large cysts (hydatid cysts). These large cysts may cause clinical problems (hydatid disease) and will have to be removed surgically.
Dogs should be dewormed regularly and they should not be allowed to eat raw meat, especially mutton or goat meat which is infected with the cysts of the dog tapeworm. Prevent children eating soil as it may be contaminated with dog tapeworm eggs. Always wash hands before eating. Also wash vegetables well.
Hydatid disease results when children swallow the eggs of the dog tapeworm.
Treatment is with mebendazole or albendazole daily for 6 weeks.
The prevention, diagnosis and treatment of sandworm infection is discussed in chapter 12.
Giardiasis is an infection with a single-celled organism (protozoa) called giardia. The cysts of giardia are swallowed in contaminated food or water. Giardia lives in the small bowel and cysts are passed in the stool. The cysts in human stools contaminate the soil and nearby water.
Giardiasis is usually asymptomatic. However, with heavy infection the child develops loose, foul-smelling, watery stools. Abdominal cramps and vomiting are common. Usually the infection resolves in a few days but it may become chronic. Chronic giardiasis may cause chronic diarrhoea with malabsorption leading to failure to thrive and malnutrition.
It is difficult to confirm the diagnosis by finding cysts in the stool. Therefore, diagnosis is usually suspected from the clinical history and confirmed when the symptoms and signs disappear after treatment.
Giardiasis can cause chronic diarrhoea and failure to thrive.
Metronidazole (Flagyl) 500 mg (under 4 years) or 800 mg (4 years or older) daily for 3 days.
It is best to avoid infection with giardia by not drinking contaminated water or eating unwashed vegetables or salad.
Amoebiasis is an infection caused by a single-celled organism (protozoa) called an amoeba which infects the large bowel. Amoebae are passed in the stool from where they can contaminate food or water causing infection in others. Therefore, the provision of toilets and a safe water supply are important to prevent amoebiasis.
Mild infection is asymptomatic. However, heavy infection causes abdominal discomfort and dysentery with blood and mucus in the stools. Amoebae can also cause abscesses in the liver. This presents with an enlarged tender liver. Severe bowel infection can result in perforation and peritonitis.
Amoebae can be seen microscopically in warm stool. A blood test for antibodies against amoebae is useful in identifying patients with amoebiasis.
Metronidazole (Flagyl) 200 mg 3 times daily for 5 days. All children with severe dysentery or suspected liver abscess must be referred urgently. A large liver abscess may need to be aspirated.
Clean water, washing hands before eating, avoiding unwashed vegetables and salads, and the safe disposal of human faeces prevents amoebiasis.
The same basic steps are needed to prevent most intestinal parasites:
Public awareness campaigns are an important method of reducing the number of infected children. Methods of preventing infection with intestinal parasites should be taught and practised at schools.
Safe toilets and clean water will prevent infection with most intestinal parasites.
Most intestinal parasites can be effectively treated with oral mebendazole or albendazole. Some require a single dose (roundworms, whipworms and pinworms) but others need a daily dose for a number of days (tapeworms). Giardia and Amoeba infections should be treated with metronidazole (Flagyl).
Regular treatment of children (e.g. deworming for roundworms) is advised for some intestinal parasites in communities where they are common.
It is important that parents are aware of the clinical features of infection with intestinal parasites and can recognise the worms if they are seen.
Bilharzia (schistosomiasis) is a disease caused by the bilharzia parasite. About 2 million people are infected with bilharzia in South Africa. There are 2 forms of bilharzia. One affects the bowel while the other affects the bladder. Bilharzia of the bladder is the most common form of bilharzia in children in South Africa.
Eggs of the bladder parasite are passed in the urine. If the urine reaches a source of water, the parasite can infect and multiply in a special snail often found in pools, dams, reservoirs, canals or slow flowing streams. Parasites released from the snail can penetrate the skin of humans. From here the parasites enter the bloodstream and are carried to the bladder. Sometimes they may also reach other organs.
In the bladder wall the parasites cause inflammation, bleeding and eventually scarring. Damage can extend to the rest of the urinary tract, resulting in urinary obstruction with chronic renal failure.
Bilharzia of the bladder is common in South Africa.
At the time of infection an itchy, papular rash may occur at the site where the parasites enter the skin (called ‘swimmers’ itch’). This may be followed a few weeks later by a flu-like illness.
Mild bladder infection with bilharzia parasites is often asymptomatic. With more severe infection, the classical sign is terminal haematuria (blood seen in the urine towards the end of micturition).
Bilharzia of the bladder usually presents with terminal haematuria.
By finding the typical bilharzia eggs in the urine under a microscope. It is best to collect urine around midday when most eggs are released. A blood test for antibodies to the parasite is also available.
Praziquantel 40 mg/kg orally as a single dose. This treatment can be given at a clinic. Unfortunately, children who live in a bilharzia region may have to be treated repeatedly for bilharzia.
Every effort must be made to prevent bilharzia infection. Never pass urine into a stream or pool of water. Standing or slow-moving water such as farm dams and irrigation furrows are the home of the bilharzias snail, especially in the eastern areas of South Africa and in Zimbabwe. Fast-moving streams are usually safe. Swimming or bathing in infected water must be avoided as this is the common way of getting bilharzias. Efforts are being made to kill the snails in high risk areas.
Do not swim in standing water where there are bilharzia snails.
Malaria is a serious illness caused by a malaria parasite which is transmitted to humans by a special type of mosquito. When a mosquito bites an infected person, human blood containing malaria parasites is taken in by the mosquito. The mosquito becomes infected (but not ill) and can then bite and infect other humans. In the human, the malaria parasite infects both red cells and the liver. Infection of the red cells causes haemolysis, resulting in anaemia. It also causes the red cells to stick together which obstructs small blood vessels. Malaria is a common cause of chronic illness and death in many low lying regions where malaria mosquitoes occur.
Malaria is an important cause of death in many parts of southern Africa.
As falciparum malaria is by far the most common form of malaria in South Africa, other rarer forms of malaria will not be considered.
The patient develops an acute illness with fever, shivering rigors and flu-like symptoms 1 to 2 weeks after being bitten by an infected mosquito. Headache, nausea and body pains are common in uncomplicated (mild) malaria. The symptoms and signs of malaria are very non-specific, making the clinical diagnosis difficult to confirm or exclude.
Severe headache, repeated vomiting and drowsiness suggest the development of severe malaria. Mild malaria may become severe and even fatal within hours.
Anyone who develops fever in a malaria area, or within 2 weeks of leaving a malaria area, must be suspected of having malaria. Thinking of malaria is the most important step in the clinical diagnosis. As the clinical symptoms and signs of malaria are very varied, it is always important to confirm the clinical suspicion. There are often no clinical signs at presentation.
Suspect malaria in anyone with a flu-like illness who lives in or has recently visited a malaria region.
Most deaths due to malaria are caused by delayed diagnosis or late treatment.
Remember that many other serious conditions may present with the same symptoms and signs as malaria, e.g. bacterial meningitis. Children may also have malaria plus another infection.
In uncomplicated malaria the patient:
In severe malaria the patient may have any of the following:
This is the most dangerous complication of severe malaria as the brain is affected and can lead to rapid death. Young children, pregnant women and people who are HIV infected are particularly susceptible to cerebral malaria. Each year many children die of cerebral malaria in Africa.
Signs of cerebral malaria must always be viewed with great concern:
Confusion is an important sign of potentially fatal cerebral malaria.
Early and accurate diagnosis with urgent treatment using the correct drugs is the key to successful management. It is important to differentiate uncomplicated from severe malaria. If possible all patients with malaria are referred to a hospital or clinic where the staff are experience in treating malaria. They must be closely followed up for the first few days. Patients with confirmed malaria are usually treated with coartemether (Coartem). Coartem is a combination of two potent, rapidly acting anti-malarial drugs which are well tolerated.
For uncomplicated malaria, one dose of Coartem should be taken immediately, then again after 8 hours, followed by a twice daily dose for the next 2 days. Each dose is 1 tablet if 10–14 kg, 2 tablets if 15–24 kg, 3 tablets if 25–34 kg and 4 tablets if 35 kg or more. Best taken with food.
Drug resistance is a major problem with malarial treatment. Most strains of malaria are now resistant to chloroquine alone or in combination with other drugs. Paracetamol is best for reducing the fever. Make sure the patient is taking enough fluids.
Uncomplicated malaria can also be treated with oral quinine. However, there are some serious side effects of quinine, e.g. myocardial toxicity.
The quinine tablets are very bitter but can be crushed and taken with jam, or mashed banana.
Severe malaria is usually treated with intravenous quinine PLUS oral doxycycline (if over 8 years) or clindamycin (oral, intramuscular or intravenous in younger children). Intravenous drugs must be started immediately and the patient urgently referred to hospital. Look for and manage hypoglycaemia, shock or convulsions.
In future intravenous artesunate will probably replace quinine as it is safer. Rectal artesunate is also an effective emergency treatment.
Using a combination of drugs for both uncomplicated and severe malaria is more effective and less likely to result in resistance in the community than monotherapy (one drug only). The patient should improve clinically within 48 hours and the fever should settle within 5 days.
Preventing mosquito bites is more effective than prophylaxis. Usually both are needed.
Preventing mosquito bites is the most effective way of avoiding malaria.
Malaria prophylaxis is needed by all who enter a malaria area (a region where malaria occurs), even if it is only a one day visit. The risk of becoming infected by malaria is particularly high in the rainy season when mosquitoes are common. Full compliance is very important. However, prophylaxis is never 100% effective.
It is best for all children under 5 years, especially children under 5 kg, not to enter a malaria area as they are at high risk for severe infection. Chloroquine alone, chloroquine with proguanil, and Coartem should not be used for prophylaxis.
Seasonal Intermittent Treatment of children in malaria regions decreases the incidence of clinical malaria.
A mother brings her 5-year-old son to the clinic because he has passed 2 roundworms with his stool. He is generally well but the mother complains that he scratches his anus at night which keeps him awake.
They ingest the roundworm eggs after playing in sand or soil. If human faeces are not disposed of correctly they can contaminate soil in the village, garden or playground. Eggs can survive for years in soil and may also contaminate pools of water or raw vegetables. This is a common public health problem.
Usually not. However, with heavy infections children may complain of abdominal pain or discomfort and lose their appetite. Roundworms can cause bowel obstruction or block a bile duct. The larvae of roundworms pass through the lungs and can cause coughing and wheezing.
With a single oral dose of mebendazole or albendazole. The mother should be told how to avoid reinfection.
A deworming programme is recommended in regions where roundworms are common.
Pinworms. These are short worms that infect the gut and leave the anus at night, causing irritation to the skin around the anus. They can also cause a vaginal discharge in girls.
A strip of Sellotape should be stuck onto the child’s skin over and next to the anus and then immediately removed. Pinworm eggs will stick to the Sellotape. These can then be seen under a microscope. The treatment is the same as for roundworms.
A malnourished child from a rural village presents at the local clinic after passing a piece of tapeworm in her stool. Pigs run free and eat human faeces. There are also a number of dogs in the village.
The pork or beef tapeworms. Pig tapeworms are more common.
Infected children are often asymptomatic. However, tapeworms can cause poor appetite, abdominal discomfort and weight loss. This child’s malnutrition may be partly explained by the tapeworm.
Probably by eating uncooked or partially cooked pork. Tapeworm eggs get passed in the stool and then may be eaten by pigs if toilets are not available. The eggs hatch in the pig’s gut and then travel in the bloodstream to the muscles where they form cysts. If these cysts in the meat are eaten by humans, they hatch out in the gut to form a tapeworm.
Oral mebendazole twice daily for 7 days.
Yes. If eggs of the pork tapeworm are passed in human faeces and then later get swallowed by another human rather than a pig, they can hatch in the gut of that person and then travel in the bloodstream to the brain where they form many small cysts. This is called neurocysticercosis and usually presents with convulsions. Neurocysticercosis is common in communities where there are pigs and human faeces are not disposed of safely.
If eggs of the dog tapeworm are ingested by humans they hatch in the gut, enter the bloodstream and are carried to organs such as the liver and lungs where they grow into large (hydatid) cysts. Therefore it is important that children do not play in areas where dog faeces are left to mix with the soil or pools of water.
Hydatid disease can be treated with oral daily mebendazole or albendazole for 6 weeks. Large cysts may have to be removed surgically.
A month after returning from holiday on a farm in the Eastern Cape, a 14-year-old child presents with a 3-week story of loose stools, and terminal haematuria for 2 days. While on holiday he swam in a farm dam.
Blood in the urine towards the end of micturition is typical of bilharzia. The bilharzia parasite settles in the wall of the bladder where it causes inflammation and bleeding.
When he swam in the farm dam. The special bilharzia snail is common in the eastern parts of South Africa where it lives in standing or slow-moving water such as farm dams or irrigation furrows. If someone with bilharzia passes urine into the water the snails can become infected. The parasites released from the snails can then penetrate the skin of anyone walking or playing in the water.
Yes. It can be treated very effectively with praziquantel. It is best to first confirm the diagnosis by seeing bilharzia parasites in a urine sample collected around midday. Chronic bilharzia infection can lead to damage of the urinary system causing renal failure.
The child may have a bowel infection with giardia, which causes diarrhoea. Although it is often acute it may last for weeks or months. Giardia is common where a safe water supply and adequate toilets are not present.
Two weeks after returning from a malaria area, a 10-year-old child presents with headache, shivering and vomiting. The mother gave her some paracetamol for the fever. A few hours later the child becomes confused and cannot stand up. The family did not take malarial prophylaxis because they planned to be in the area for 2 days only.
Yes. Malaria has an incubation period of 1 to 2 weeks and presents with fever and a flu-like illness.
At presentation it was uncomplicated, with fever and vomiting. However, within hours she was confused and could not stand. This indicates severe, probably cerebral malaria. Malaria can progress from uncomplicated to severe within hours if not treated.
By examining a blood smear or performing a malaria rapid antigen test.
She must be admitted to hospital urgently as cerebral malaria can be fatal. She needs to be treated with intravenous quinine plus either doxycycline or clindamycin. Uncomplicated malaria can be adequately treated with oral Coartem provided the clinical diagnosis has been confirmed.
The only way to confidently avoid malaria is not to enter a malaria area. However, malaria can usually be avoided by making efforts not to be bitten by mosquitoes and by taking malaria prophylaxis. Insecticide impregnated bed nets are very effective. Also keeping indoors after sunset with mosquito screens on the door and windows. Wear long trousers and sleeves, and shoes and socks if going out in the evening or early morning, when mosquitoes are most active.
The choice is atovaquone and proguanil (Malanil) for children of 10kg or more, or mefloquine (Larium) for children of 5 kg or more. Children over 8 years can also use doxycycline. The medication must be taken correctly, including for the correct period after leaving the malaria area. Prophylaxis must be taken even for a one day visit.