Child healthcare: a learning programme for professionals

11
Parasites
Objectives
unusual parasites not normally seen in healthy children (e.g. Toxoplasmosis).
When you have completed this unit you should be able to: 11-2 Which are the common intestinal
parasites?
In Southern Africa the common intestinal • Diagnose and treat amoebiasis.
• Diagnose and treat bilharzia.
INTRODUCTION
11-1 What are parasites?
ROUNDWORMS
These are small creatures (animals) which invade and infect (infest) the body. They may be either: 11-3 What is a roundworm?
External parasites which live on or in the Roundworms are the most common parasites found in the gut of children. The worms are Internal parasites which live in the body. Many internal parasites live in the bowel long. They look like pale garden earth worms.
(i.e. intestinal parasites such as worms). Other parasites live in the blood (e.g. 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.
PARASITES 183
A large bunch (bolus) of worms can cause colic (cramping abdominal pain) and even Roundworms are the most common bowel
parasite in many poor countries.
of worms may be palpable on abdominal examination.
NOTE The roundworm is Ascaris lumbricoides.
Migrating worms can get stuck in the bile Infection with roundworms is called ascariasis.
duct, resulting in acute, severe pain over the liver (biliary colic).
11-4 How do children get roundworms?
NOTE Roundworms can also cause bowel
If human faeces are not disposed of in a perforation, volvulus, intussusception, colangitis hygienic way, or if sewerage sludge is used as and pancreatic duct obstruction. With heavy a garden fertiliser, children can swallow and infections, bunches of roundworms can be get infected by roundworm eggs. Roundworm seen in a plain abdominal X-ray. Do not give mebendazole or albendazole if acute abdominal eggs can survive in soil for years. Playing or pain is present as treatment increases the worms’ crawling in contaminated soil or eating raw tendency to migrate and may precipitate bowel vegetables that have not been washed may obstruction. Surgery must be considered if there result in infection. High prevalence rates are common in communities with poor sanitation. This is a major public health problem in many 11-6 How can roundworms cause chest
problems?
Roundworm eggs hatch in the child’s small The larvae (which hatch out of the eggs in the bowel, and the newly hatched larvae then pass gut) can causes respiratory symptoms and signs through the bowel wall into the bloodstream during the time that they are migrating through and are carried to the alveoli of the lungs. the lungs. Children with roundworm larvae in From here they make their way up the bronchi the lungs present with a dry cough or wheeze.
and trachea then get swallowed. In the small bowel the roundworm larvae mature into adult NOTE A high eosinophil count in the peripheral
worms where they can live for 2 years.
blood (10% or more) is typical. Chest X-ray may show a pneumonitis.
11-5 Do roundworms in the gut cause
11-7 How are roundworms treated?
clinical problems?
healthy and have no symptoms. Often the only way the parents know that their children Mebendazole orally 100 mg (i.e. 1 tablet) have roundworms, is when worms are seen in twice a day for 3 days if below 5 years and the stool. Sometimes worms can be vomited. 500 mg as a single dose if 5 years or older.
When the child is ill with a fever, roundworms may make their way up the child’s oesophagus tablets) for children below 2 years and 400 Large numbers of worms in the bowel can cause problems: 11-8 How can infection with roundworms
be prevented?
(adequate sanitation), e.g. water borne sewerage or correctly built pit latrines 184 PARASITES
By washing raw vegetables before they are 11-11 What are the clinical features of
whipworm infection?
Whipworms usually infect children over 5 years of age. If the infection is light there are usually no symptoms or signs. Heavy infection 11-9 When is deworming recommended?
Rectal prolapse may occur with very heavy for children between the ages of 2 and 5 infections. With prolapse, the worms may years in communities with poor hygiene and be seen attached to the rectal mucosa.
inadequate sanitation (poor toilet facilities). This should be done even if there is no history blood loss in the stool. This may be severe.
of roundworms in the stool. Medication is usually given at the local primary care clinic or in schools. Deworming has been found to Whipworm infection can cause iron deficiency
improve the learning capacity and growth of anaemia.
11-12 What is the treatment of whipworm
infection?
for deworming is the same as for treating roundworms. Both these drugs are highly 1. Prevention through good hand hygiene, washing raw vegetables and the correct disposal of human faeces (as with prevention of roundworms) Regular deworming of young children is
2. Mebendazole or albendazole, as given for recommended in communities where roundworms
are common.
3. Treat iron deficiency anaemia with oral iron.
WHIPWORMS
PINWORMS
11-13 What are pinworms?
11-10 What are whipworms?
Pinworm infection is very common. They are small, thin worms (about 4 cm long). Pinworms of children in Southern Africa. They are are especially common where children sleep short, thin worms (about 4 cm) that attach or play together in crowded conditions. Adult themselves to the mucosa of the large bowel female worms pass out the anus at night to lay where they cause bleeding. It is rare to see the eggs on the perineum. Eggs are swallowed from contaminated fingers, clothing or bed linen. (swallowed) with soil. The eggs hatch in the and sanitation are of a high standard. They are child’s gut and the larvae attach to the bowel wall. Unlike roundworms, the larvae do not NOTE The pinworm is Enterobius vermicularis.
NOTE The whipworm is Trichuris trichura. The eggs
in the stool have a typical ‘tea tray’ appearance.
PARASITES 185
11-14 What are the clinical features of
11-18 What are the clinical features of
pinworm infection?
hookworm infection?
Perianal itching and scratching at night. This Usually, there are no symptoms unless there may cause loss of sleep. Secondary infection is heavy infection. The child may have an of the scratched skin is common. In girls the unusually large appetite and want to eat sand. worms may enter the vulva causing irritation In severe cases there may be signs of iron Pinworm infection presents with perianal itching
11-19 How is hookworm infection
diagnosed?
and scratching, especially at night.
Worms and their eggs may be found in the stools.
11-15 How is pinworm infection
diagnosed?
11-20 What is the treatment of hookworm
The clinical diagnosis can be confirmed by the infection?
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 NOTE Pyrantel (Combantrin) orally 10 mg/kg as a
immediately removed. In this way eggs can be collected and identified under a microscope.
11-16 What is the treatment of pinworms?
TAPEWORMS
Mebendazole or albendazole, as used for roundworms 11-21 What are tapeworms?
HOOKWORMS
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 11-17 What are hookworms?
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 poor sanitation, hookworm eggs in the stool by animals (pigs or cows). The eggs hatch contaminate the soil and hatch rapidly. They in the animal’s gut and are carried in the then infect the feet of barefoot children. Once bloodstream to the muscles of the animals the skin is penetrated, hookworms behave like where they become tapeworm cysts. Eating roundworms as they enter the bloodstream infected, uncooked meat of these animals and travel via the lungs to get into the small completes the life cycle of the tapeworm when bowel. The worms attach to the bowel mucosa the eggs hatch, resulting in adult worms living NOTE There are two types of hookworm,
Ancylostoma duodenale and Necator americanus.
Most tapeworms result from eating poorly cooked
pork which is infected with tapeworm cysts.
186 PARASITES
NOTE The pork tapeworm is Taenia solium and the
are a common cause of fits in children that live beef tapeworm is Taenia saginata.
in rural areas where toilets are not available. Good sanitation, safe water, hand-washing 11-22 How is tapeworm infection
and washed vegetables will reduce the risk of diagnosed?
Small segments of the worm are seen in the stool or may be found in the bed. Often there Swallowed pork tapeworm eggs from human
are no other symptoms. However, tapeworms faeces result in tapeworm cysts in the brain.
can cause abdominal discomfort, failure to thrive and loss of appetite.
NOTE The tapeworm cysts (cysticerci) are best
identified in the brain by MRI or CT scanning.
11-23 What is the treatment of tapeworm
With time they become calcified and can be infection?
seen on X-ray. Cysts may also occur in muscles. Antibody tests are of little help. Treatment of Mebendazole orally 100 mg twice daily for 7 neurocysticercosis in hospital is with steroids and 11-24 How can tapeworm infection be
prevented?
HYDATID DISEASE
If possible, animals should be slaughtered in a registered abattoir where all meat is inspected 11-26 What is hydatid disease?
to ensure that it is not infected by tapeworm cysts. Cooking meat well kills the cysts. This is caused by the dog tapeworm which Therefore, avoid eating raw or partially cooked can occur in the gut of dogs. Eggs, which are meat. Meat lightly cooked on an open fire may 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 so that it cannot be eaten by pigs. This will prevent the pigs from becoming infected with tapeworm cysts. Parts of the Eastern If eggs of the dog tapeworm are swallowed by Cape of South Africa are particularly heavily 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 In villages, pigs must be prevented from eating
clinical problems (hydatid disease) and will human faeces.
11-25 Can tapeworm cysts enter the brain?
they should not be allowed to eat raw meat, Yes. Sometimes the eggs of the pork tapeworm, which have been passed in human faeces, are infected with the cysts of the dog tapeworm. swallowed by other humans (instead of by pigs) Prevent children eating soil as it may be in food or water contaminated by infected human faeces. The eggs hatch in the child’s Always wash hands before eating. Also wash 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 Hydatid disease results when children swallow
cysts (neurocysticercosis) which cause fits the eggs of the dog tapeworm.
(convulsions). Tapeworm cysts in the brain PARASITES 187
Treatment is with mebendazole or albendazole 11-29 What is the treatment of giardia
infection?
NOTE The dog tapeworm is Echinococcus
Metronidazole (Flagyl) 500 mg (under 4 years) or 800 mg (4 years or older) daily for 3 days.
The prevention, diagnosis and treatment of It is best to avoid infection with giardia by sandworm infection is discussed in Unit 12. not drinking contaminated water or eating unwashed vegetables or salad.
GIARDIASIS
AMOEBIASIS
11-27 What is giardiasis?
11-30 What is amoebiasis?
Giardiasis is an infection with a single-celled Amoebiasis is an infection caused by a single- organism (protozoa) called giardia. The cysts celled organism (protozoa) called an amoeba of giardia are swallowed in contaminated food or water. Giardia lives in the small bowel and are passed in the stool from where they can cysts are passed in the stool. The cysts in human contaminate food or water causing infection in stools contaminate the soil and nearby water.
others. Therefore, the provision of toilets and NOTE Giardia lamblia is the cause of giardiasis.
a safe water supply are important to prevent amoebiasis.
11-28 What are the clinical features of
NOTE Entamoeba histolytica is the amoeba which
giardia infection?
Giardiasis is usually asymptomatic. However, with heavy infection the child develops loose, 11-31 What are the clinical features of
amoebiasis?
Mild infection is asymptomatic. However, the infection resolves in a few days but it may heavy infection causes abdominal discomfort become chronic. Chronic giardiasis may cause and dysentery with blood and mucus in the chronic diarrhoea with malabsorption leading stools. Amoebae can also cause abscesses in to failure to thrive and malnutrition.
the liver. This presents with an enlarged tender It is difficult to confirm the diagnosis by liver. Severe bowel infection can result in finding cysts in the stool. Therefore, diagnosis is usually suspected from the clinical history and confirmed when the symptoms and signs warm stool. A blood test for antibodies against amoebae is useful in identifying patients with amoebiasis.
Giardiasis can cause chronic diarrhoea and failure
to thrive.
11-32 What is the treatment of amoebiasis?
Metronidazole (Flagyl) 200 mg 3 times daily NOTE Giardia is a common cause of ‘travellers’
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.
188 PARASITES
Clean water, washing hands before eating, avoiding unwashed vegetables and salads, and the safe disposal of human faeces prevents It is important that parents are aware of the clinical features of infection with intestinal parasites and can recognise the worms if they 11-33 How can infection with many types
of intestinal parasite be prevented?
The same basic steps are needed to prevent most intestinal parasites: BILHARZIA
11-35 What is bilharzia?
correctly-made pit toilets (VIP toilets). Never pass urine or stool near a stream or 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. 3. Always use a clean, safe source of water for 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, 6. Prevent pigs from eating human faeces.
canals or slow flowing streams. Parasites 7. Do not leave dog faeces lying around.
released from the snail can penetrate the skin Public awareness campaigns are an important of humans. From here the parasites enter the method of reducing the number of infected bloodstream and are carried to the bladder. children. Methods of preventing infection Sometimes they may also reach other organs.
with intestinal parasites should be taught and inflammation, bleeding and eventually scarring. Damage can extend to the rest of the Safe toilets and clean water will prevent infection
urinary tract, resulting in urinary obstruction with most intestinal parasites.
NOTE Bilharzia (schistosomiasis) is caused by either
Schistosoma haemotobium (bladder parasite) or
11-34 What is the treatment of intestinal
Schistosoma mansoni (bowel parasite).
parasites?
Most intestinal parasites can be effectively Bilharzia of the bladder is common in South
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). 11-36 What are the clinical features of
bilharzia of the bladder?
treated with metronidazole (Flagyl).
At the time of infection an itchy, papular rash Regular treatment of children (e.g. deworming may occur at the site where the parasites enter for roundworms) is advised for some intestinal the skin (called ‘swimmers’ itch’). This may be followed a few weeks later by a flu-like illness.
PARASITES 189
parasites is often asymptomatic. With more severe infection, the classical sign is terminal haematuria (blood seen in the urine towards 11-40 What is malaria?
Malaria is a serious illness caused by a malaria parasite which is transmitted to humans by a Bilharzia of the bladder usually presents with
special type of mosquito. When a mosquito terminal haematuria.
bites an infected person, human blood containing malaria parasites is taken in by the NOTE Bilharzia of the bowel may cause dysentery.
mosquito. The mosquito becomes infected (but not ill) and can then bite and infect other 11-37 How is the diagnosis of bilharzia of
humans. In the human, the malaria parasite the bladder confirmed?
infects both red cells and the liver. Infection of the red cells causes haemolysis, resulting By finding the typical bilharzia eggs in the in anaemia. It also causes the red cells to stick urine under a microscope. It is best to collect together which obstructs small blood vessels. Malaria is a common cause of chronic illness released. A blood test for antibodies to the and death in many low lying regions where NOTE Eosiniphilia in the blood is usually present
with bilharzia.
Malaria is an important cause of death in many
parts of southern Africa.
11-38 What is the treatment of bilharzia?
Praziquantel 40 mg/kg orally as a single As falciparum malaria is by far the most dose. This treatment can be given at a clinic. common form of malaria in South Africa, other Unfortunately, children who live in a bilharzia rarer forms of malaria will not be considered.
region may have to be treated repeatedly for NOTE Almost all malaria in Southern Africa is
caused by Plasmodium falciparum which is transmitted by female Anopheles mosquitoes 11-39 How can bilharzia be prevented?
Every effort must be made to prevent bilharzia infection. Never pass urine into a stream or 11-41 What are the clinical signs of
pool of water. Standing or slow-moving water malaria?
such as farm dams and irrigation furrows are The patient develops an acute illness with the home of the bilharzias snail, especially fever, shivering rigors and flu-like symptoms in the eastern areas of South Africa and in 1 to 2 weeks after being bitten by an infected Zimbabwe. Fast-moving streams are usually mosquito. Headache, nausea and body pains safe. Swimming or bathing in infected water are common in uncomplicated (mild) malaria. must be avoided as this is the common way of The symptoms and signs of malaria are very getting bilharzias. Efforts are being made to non-specific, making the clinical diagnosis Do not swim in standing water where there are
drowsiness suggest the development of severe bilharzia snails.
malaria. Mild malaria may become severe and even fatal within hours.
NOTE Infection of other organs such as the liver
(jaundice), gut (diarrhoea), lungs (respiratory
190 PARASITES
distress) and kidneys (oliguria with renal failure) may occur. Massive haemolysis (blackwater fever) Is not vomiting repeatedly, and is able to area, or within 2 weeks of leaving a malaria NOTE In uncomplicated malaria the parasite count
area, must be suspected of having malaria. on a thin blood smear is less than 5%, i.e. less Thinking of malaria is the most important than 5% of red cells containing malaria parasites.
step in the clinical diagnosis. As the clinical In severe malaria the patient may have any of symptoms and signs of malaria are very varied, it is always important to confirm the clinical suspicion. There are often no clinical signs at Hypoglycaemia, jaundice or severe anaemia (Hb less than 5 g/dl) Suspect malaria in anyone with a flu-like illness
who lives in or has recently visited a malaria
NOTE In severe malaria the parasite count is well
11-42 How is the diagnosis of malaria
over 5% (hyperparasitaemia). The higher the confirmed?
count, the more severe the malaria. Metabolic acidosis may occur.
1. Seeing the malaria parasites within red 11-44 What is cerebral malaria?
the traditional ways of confirming the diagnosis. Repeated smears may be needed This is the most dangerous complication of severe malaria as the brain is affected and can may be negative early in the infection.
lead to rapid death. Young children, pregnant 2. A blood test to detect malaria proteins women and people who are HIV infected are (rapid antigen test) is also useful in making particularly susceptible to cerebral malaria. a rapid diagnosis. It is very reliable and Signs of cerebral malaria must always be diagnosis of malaria as soon as possible.
Depressed level of consciousness, i.e. drowsy, unable to stand, confused or Most deaths due to malaria are caused by delayed
diagnosis or late treatment.
Remember that many other serious conditions Confusion is an important sign of potentially fatal
may present with the same symptoms and signs as malaria, e.g. bacterial meningitis. Children cerebral malaria.
may also have malaria plus another infection.
NOTE In cerebral malaria the large numbers of
parasites obstruct the normal blood flow to the
11-43 How can you tell whether malaria is
uncomplicated or severe?
Is fully alert and able to stand and walk PARASITES 191
11-45 How is uncomplicated malaria
In future intravenous artesunate will probably treated?
replace quinine as it is safer. Rectal artesunate is also an effective emergency treatment.
Early and accurate diagnosis with urgent treatment using the correct drugs is the key NOTE A loading dose of quinine 20 mg/kg diluted
to successful management. It is important in 5% dextrose water (10 ml/kg) must always be to differentiate uncomplicated from severe given as a slow infusion over 4 hours and never as a bolus. This is followed by 10 mg/kg 8 hourly malaria. If possible all patients with malaria are intravenously. Change to oral quinine as soon as 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 uncomplicated and severe malaria is more treated with coartemether (Coartem). Coartem effective and less likely to result in resistance in is a combination of two potent, rapidly acting the community than monotherapy (one drug anti-malarial drugs which are well tolerated.
only). The patient should improve clinically within 48 hours and the fever should settle Coartem should be taken immediately, then again after 8 hours, followed by a twice daily 11-47 How is malaria prevented?
dose for the next 2 days. Each dose is 1 tablet if 10–14 kg, 2 tablets if 15–24 kg, 3 tablets if 1. Pregnant women and young children should 25–34 kg and 4 tablets if 35 kg or more. Best not enter a malaria areas if at all possible.
evening and early morning. Therefore, stay malarial treatment. Most strains of malaria doors or wear light coloured clothes, long are now resistant to chloroquine alone or in sleeves and trousers with shoes and socks combination with other drugs. Paracetamol is best for reducing the fever. Make sure the 3. Use a bed net impregnated with insecticide Uncomplicated malaria can also be treated with 4. Use insect repellent on the skin and clothes oral quinine. However, there are some serious or burn repellent coils or pads or sprays at side effects of quinine, e.g. myocardial toxicity. NOTE The dose of oral quinine is 10 mg/kg 8 hourly
for 7 days PLUS clindamycin 5 mg/kg 8 hourly for 7
recommended for short visits to a malaria days or doxycycline (if over 8 years of age) 4 mg/kg immediately then 2 mg/kg daily for 7 days.
6. By reducing the number of mosquitoes.
The quinine tablets are very bitter but can be Preventing mosquito bites is more effective crushed and taken with jam, or mashed banana.
than prophylaxis. Usually both are needed.
11-46 How is severe malaria treated?
Preventing mosquito bites is the most effective
way of avoiding malaria.
intravenous quinine PLUS oral doxycycline (if over 8 years) or clindamycin (oral, 11-48 What malaria prophylaxis is
recommended?
children). Intravenous drugs must be started immediately and the patient urgently Malaria prophylaxis is needed by all who enter referred to hospital. Look for and manage a malaria area (a region where malaria occurs), hypoglycaemia, shock or convulsions.
even if it is only a one day visit. The risk of 192 PARASITES
becoming infected by malaria is particularly CASE STUDY 1
high in the rainy season when mosquitoes are common. Full compliance is very important. A mother brings her 5-year-old son to the However, prophylaxis is never 100% effective.
clinic because he has passed 2 roundworms with his stool. He is generally well but the proguanil) for children of 10 kg or more. It mother complains that he scratches his anus at 2. Mefloquine (Larium) for children of 5 kg 1. How do children get roundworms?
3. Doxycycline for older children (over 8 They ingest the roundworm eggs after playing in sand or soil. If human faeces are not It is best for all children under 5 years, disposed of correctly they can contaminate especially children under 5 kg, not to enter a soil in the village, garden or playground. Eggs malaria area as they are at high risk for severe can survive for years in soil and may also infection. Chloroquine alone, chloroquine contaminate pools of water or raw vegetables. with proguanil, and Coartem should not be This is a common public health problem.
NOTE Malanil daily ¼ tablet if 5–20 kg, ½ tablet
2. Can roundworms cause clinical
if 21–30 kg, ¾ tablet if 31–45 kg and 1 tablet if problems?
over 45 kg starting one day before entering and stopping one week after leaving a malaria area. Usually not. However, with heavy infections Mefloquine weekly ¼ tablet if 5–20 kg, ½ tablet if 21–30 kg, ¾ tablet if 31–45 kg and 1 tablet if pain or discomfort and lose their appetite. over 45 kg starting one week before entering and Roundworms can cause bowel obstruction or stopping 4 weeks after leaving a malaria area. block a bile duct. The larvae of roundworms Doxycycline 100 mg daily starting 1 day before entering and stopping 4 weeks after leaving a Seasonal Intermittent Treatment of children 3. How should this child be treated?
in malaria regions decreases the incidence of clinical malaria.
With a single oral dose of mebendazole or albendazole. The mother should be told how to avoid reinfection.
11-49 How can the number of mosquitoes
be reduced?
4. Is routine deworming recommended for
all children?
with the use of controlled spraying around homes with insecticides. This is done by regions where roundworms are common.
5. What is a common cause of perianal itch
at night in children?
NOTE Malarial mosquitoes have become resistant
to many insecticides. The controlled use of DDT
Pinworms. These are short worms that infect is very effective but remains controversial due to the gut and leave the anus at night, causing the risk of environmental pollution and dangers irritation to the skin around the anus. They to other animals and possibly the newborn infant.
can also cause a vaginal discharge in girls.
PARASITES 193
6. How can the diagnosis be confirmed?
5. Can tapeworms affect the brain?
A strip of Sellotape should be stuck onto the Yes. If eggs of the pork tapeworm are passed child’s skin over and next to the anus and then in human faeces and then later get swallowed immediately removed. Pinworm eggs will stick by another human rather than a pig, they to the Sellotape. These can then be seen under can hatch in the gut of that person and then a microscope. The treatment is the same as for 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 CASE STUDY 2
communities where there are pigs and human faeces are not disposed of safely.
A malnourished child from a rural village presents at the local clinic after passing a piece 6. What problems can be caused by the dog
of tapeworm in her stool. Pigs run free and eat tapeworm?
human faeces. There are also a number of dogs 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 1. What are the common types of
the liver and lungs where they grow into large tapeworms in children?
(hydatid) cysts. Therefore it is important that The pork or beef tapeworms. Pig tapeworms 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 2. What is the clinical presentation of
tapeworms?
Large cysts may have to be removed surgically.
Infected children are often asymptomatic. However, tapeworms can cause poor appetite, CASE STUDY 3
abdominal discomfort and weight loss. This child’s malnutrition may be partly explained by the tapeworm.
A month after returning from holiday on a farm in the Eastern Cape, a 14-year-old child 3. How did this child get infected with a
presents with a 3-week story of loose stools, tapeworm?
and terminal haematuria for 2 days. While on holiday he swam in a farm dam.
Probably by eating uncooked or partially cooked pork. Tapeworm eggs get passed in the 1. What is the common cause of terminal
stool and then may be eaten by pigs if toilets haematuria?
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 micturition is typical of bilharzia. The bilharzia the meat are eaten by humans, they hatch out parasite settles in the wall of the bladder where it causes inflammation and bleeding.
4. What is used to treat intestinal
2. When did the infection probably occur?
tapeworms?
When he swam in the farm dam. The special Oral mebendazole twice daily for 7 days.
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 194 PARASITES
irrigation furrows. If someone with bilharzia indicates severe, probably cerebral malaria. passes urine into the water the snails can Malaria can progress from uncomplicated to become infected. The parasites released from the snails can then penetrate the skin of anyone walking or playing in the water.
3. How can the diagnosis be confirmed?
By examining a blood smear or performing a 3. Can bilharzia be treated?
Yes. It can be treated very effectively with praziquantel. It is best to first confirm the 4. What is the correct treatment?
diagnosis by seeing bilharzia parasites in a urine sample collected around midday. She must be admitted to hospital urgently as Chronic bilharzia infection can lead to damage cerebral malaria can be fatal. She needs to be of the urinary system causing renal failure.
treated with intravenous quinine plus either doxycycline or clindamycin. Uncomplicated malaria can be adequately treated with oral 4. What is the probable cause of the
Coartem provided the clinical diagnosis has diarrhoea for the past 3 weeks?
The child may have a bowel infection with giardia, which causes diarrhoea. Although it 5. How can malaria be prevented while on
is often acute it may last for weeks or months. holiday?
Giardia is common where a safe water supply and adequate toilets are not present.
The only way to confidently avoid malaria is not to enter a malaria area. However, malaria can usually be avoided by making efforts not 5. Which drug is used to treat giardiasis?
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 CASE STUDY 4
the door and windows. Wear long trousers and sleeves, and shoes and socks if going out in the Two weeks after returning from a malaria area, evening or early morning, when mosquitoes a 10-year-old child presents with headache, shivering and vomiting. The mother gave her some paracetamol for the fever. A few hours 6. What malaria prophylaxis should be
later the child becomes confused and cannot stand up. The family did not take malarial prophylaxis because they planned to be in the (Malanil) for children of 10kg or more, or mefloquine (Larium) for children of 5 kg or more. Children over 8 years can also use 1. Do you think this child has malaria?
doxycycline. The medication must be taken Yes. Malaria has an incubation period of 1 to correctly, including for the correct period after 2 weeks and presents with fever and a flu-like leaving the malaria area. Prophylaxis must be 2. How severe is the infection?
At presentation it was uncomplicated, with fever and vomiting. However, within hours she was confused and could not stand. This

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