Schistosomiasis

The Virtual Doctors work

This month we are back in Chongwe at the Rural Health clinic. Chongwe RHC is in Chongwe district in Lusaka province. Approximately 6% of the population of Lusaka province live in this district.

At this time of year Chongwe has pleasant sunny weather, generally in the mid 20s with night times around 11 ⁰C.

Chongwe Market

There are some amazing festivals in Zambia, all colourful, noisy and full of merriment but deeply rooted in a serious belief. In Chongwe the Soli people, who are said to be the original inhabitants of Lusaka province, celebrate Chakwela Mukumbi. This takes place in October. Literally translated Chakwela Mukumbi means “pulling down the clouds”. The ancestors and God are prayed to for good rains by her royal highness Chieftainess Nkomeshya II. This marks the start of the farming season and symbolically a small area of the royal field is burnt and her highness plants a few seeds. There are dances during the ceremony performed by different cultural groups that make up the Soli kingdom.

Blessing the seeds and praying for good rain

Virtual Doctors Support 10 clinics and the district general hospital in Chongwe district

Chongwe rural health clinic is always busy and the last few months have been no exception. A 9 year old boy was brought to the clinic by his mother. He had abdominal pain (tummy ache) and was passing blood at the end of urination. He had previously been treated with praziquantal 1200mg as a one off dose (an anthelmintic or anti-worm drug) a month earlier for Schistosomiasis. There had been no improvement. The Clinical officer checked his urine again and on urinalysis found 2+ blood, Schistosoma hematobium ova (eggs) present. On examination he had lower abdominal tenderness. There were no reports of local waterways being infested with schistosomiasis.

Our volunteer doctor advised that although the boy had been given the correct treatment this only cures just over half the patients. Success is greatly improved by repeating the dose after 4 to 6 weeks. He recommended the boy was given another dose of praziquantel.

What is Schistosomiasis (Also known as Bilharzia)?

Schistosomiasis is a parasitic infection caused by flukes (parasitic worms) that live in freshwater. It is found most commonly in Africa. It is the 3rd most devastating tropical disease in the world after malaria and intestinal helminthiasis(worms) and so causes major morbidity and mortality to the populations of Africa, south America, the Caribbean, middle East and Asia. More than 207 million people (85% who live in Africa) are infected with Schistosomiasis. Globally 200,000 deaths are attributed to schistosomiasis a year. The parasite can remain in the body for many years and cause damage to organs such as the bladder, kidneys and liver. In women it contributes both to miscarriage and infertility.

Also known as Bilharzia or snail fever, schistosomiasis was discovered by a German surgeon working in Cairo called Theodore Bilharz. He first identified the Schistosoma hematobium (parasitic worm), the cause of the infection, in 1851.

These worms live in fresh water. They have snail hosts, different snails for different types of Schistosoma. There are many different worms each having a preference on snail host and on area of the body they like to infect. The main human worms, for those who like to know the names, are: S. haematobium (using the Bulinus snail host), S. mansoni (using Biomphalaria snail host) and S. jaconicum (using the Oncomelania snail host).

As these worms live in fresh water. People are exposed to infection by exposure to infected water, for example through agricultural work, domestic chores such as washing clothes, bathing or swimming. Showers taken from unfiltered water directly from lakes or rivers may spread infection but the worms are not found in the sea, chlorinated swimming pools or properly treated water supplies.

Signs and Symptoms

Whilst in contaminated water, the tiny worms burrow into your skin. The worms then move through your blood to areas such as the liver and bowel. After a few weeks the worms lay eggs. Some eggs remain inside the body and others are passed out in the person’s urine or faeces.

Schistosomiasis is due to the body’s immune system reacting to these Schistosoma eggs trapped in the body tissues. This is called an immunologic reaction. The antigens from the eggs stimulate something called a granulomatous reaction involving many parts of the immune system and it is this which results in the clinical disease.

Without treatment the worms can go on laying eggs for several years.

The eggs that pass out of the body into water release tiny larvae. These need to grow inside the freshwater snail host for a few weeks before they are able to infect anyone else.

On initial infection there may be no symptoms and symptoms may not appear for months or years. Occasionally people get small, itchy red bumps on their skin for a few days where the worms burrow in. This is sometimes known as ‘swimmers itch.’

After a few weeks some people may get the some of the following symptoms: a high fever, cough, diarrhoea (with or without blood), muscle and joint pains, abdominal pain, haematuria (blood in the urine typically at the end of urination) and feeling generally unwell. These symptoms are known as acute schistosomiasis or Katayama syndrome, and often get better on their own within a few weeks. It is really important, however, that this is treated as the parasite remains in the body and can cause serious long term problems if left unchecked.

Chronic Schistosomiasis

Diagnosis is made by taking the history, examination and blood, urine and faecal samples. The blood samples may show anaemia and a rise in certain white blood cells common in parasitic infections, kidney and liver function. Urine and faecal microscopy is used to identify the Schistosoma. This can also be used to work out the intensity of the infection in endemic areas, as many of the complications are related to parasitic load (amount of parasite).

Treatment

Treatment is with an anti-worm medication called Praziquantal 60mg/kg in 3 doses over one day remains the treatment of choice. It has cure rates of between 60-95%. It also helps reduce egg excretion in those not cured. A repeat dose can be given 4-6weeks later.

Steroids are sometimes used to help relieve symptoms of acute schistosomiasis or those caused by damage to the brain or nervous system.

Thank you for taking time to read this blog. I hope you enjoy reading about the varied cases sent to the Virtual Doctor volunteers from the hard working clinical officers and nurses in Zambia. And thank you for your continuing support.

Disclaimer: This article is for information only and shouldn’t be used for diagnosis or treatment of medical conditions. If you have any concerns about your health consult a doctor or other health professional.