Skip to main content
Printable page generated Monday, 28 Nov 2022, 00:49
Use 'Print preview' to check the number of pages and printer settings.
Print functionality varies between browsers.
Unless otherwise stated, copyright © 2022 The Open University, all rights reserved.
Printable page generated Monday, 28 Nov 2022, 00:49

Communicable Diseases Module: 39. Diseases of Poor Hygiene and Environmental Health: Trachoma, Scabies and Podoconiosis

Study Session 39  Diseases of Poor Hygiene and Environmental Health: Trachoma, Scabies and Podoconiosis


This study session focuses on three significant health problems in Ethiopia, which are common in communities where there is poor hygiene and sanitation, and where people find it difficult to keep their environment clean. You have already learned a lot in this Module about diarrhoeal diseases and other infections in which poor hygiene is a major contributory cause. In this study session, we contrast three other conditions where the local environment makes an important contribution:

  • Trachoma, a potentially blinding eye disease caused by bacteria, but flies are a strong environmental factor in its transmission;
  • Scabies, a persistent irritating rash caused by tiny crawling mites that burrow into the skin;
  • Podoconiosis, a form of elephantiasis (swollen limbs with thickened skin) that is not caused by an infection at all – but by irritating particles of red clay soil causing a damaging reaction in the skin.

A common feature of these diseases is the lack of clean water for washing, and lack of education about their causes and how to prevent them. As you will see, washing the body and clothes regularly and disposing of rubbish safely is the key to prevention and control. In this study session, you will learn about the causes, modes of transmission, treatment and prevention of trachoma, scabies and podoconiosis. A better understanding of these diseases will help you to diagnose, treat or refer patients and educate your community on prevention measures.

Learning Outcomes for Study Session 39

When you have studied this session, you should be able to:

39.1  Define and use correctly all of the key words printed in bold. (SAQs 39.1 and 39.2)

39.2  Describe the causes of scabies, trachoma and podoconiosis and the environmental factors that contribute to their prevalence. (SAQs 39.1, 39.2 and 39.3)

39.3  Describe the symptoms, diagnosis, treatment and referral criteria for scabies, trachoma and podoconiosis. (SAQs 39.1 and 39.2)

39.4  Describe the prevention and control measures at community level against scabies, trachoma and podoconiosis. (SAQs 39.1, 39.2, 39.3 and 39.4)

39.1  Trachoma – the ‘quiet blindness’

Trachoma is an infectious eye disease that can eventually cause blindness if left untreated. Infection of the eyes with the bacteria Chlamydia trachomatis usually occurs in childhood, but infected people generally do not develop severe sight problems until adulthood.

It is therefore essential that you are able to identify the early signs of the disease and treat patients appropriately in order to avoid severe complications developing later in life.

First, we will describe the infectious agents that cause trachoma, their modes of transmission and the clinical manifestations of the disease. This knowledge will enable you to identify people with symptoms, grade the signs according to a classification of severity, and decide whether you should treat patients yourself or refer them to a health centre or hospital. Then you will learn how to give health education about trachoma and its prevention in your community.

39.1.1  What causes trachoma?

Look closely at the diagram of the eye in Figure 39.1. Identify the areas labelled as the conjunctiva and the cornea. In the initial stages of trachoma, the bacteria Chlamydia trachomatis primarily infect the conjunctiva (pronounced ‘kon-junk-tie-vah’). This is a thin clear membrane that covers the inner surface of the eyelid and the white part of the eyeball. First it becomes itchy and inflamed (red, swollen and painful); later it becomes scarred and the eyelashes turn inwards.

The cornea is the thick transparent tissue over the front part of the eye, covering the white, black and coloured areas. The damage to the cornea is not due to the bacteria, but by persistent scratching from the eyelashes, which have turned inwards due to scarring in the conjunctiva.

Anatomical structure of the eye
Figure 39.1  Anatomical structure of the eye. The conjunctiva lining the inside of the eyelids is the area most visibly affected by trachoma in the early stages. (Source: WHO, 1993, Primary Healthcare Level Management of Trachoma)

39.1.2  Modes of transmission of trachoma

The bacteria that cause trachoma are transmitted mainly by contact with the discharge (pus) coming from an infected person’s eyes. Note that direct transmission from one person’s eyes to the eyes of another person is unusual, but direct mother-to-newborn transmission can occur during birth if the mother has Chlamydia bacteria in her birth canal. These bacteria can live in the genitals of males and females, causing a sexually transmitted infection, which can get into the eyes of the baby as it is born. This is why tetracycline eye ointment (1%) is applied to the eyes of all babies as part of routine newborn care.

Routine newborn care is described in the Modules on Postnatal Care and Integrated Management of Newborn and Childhood Illness (IMNCI)..

However, the most common routes by which Chlamydia bacteria get into the eyes and cause trachoma are through:

  • Flies landing on the face of an infected person and then carrying the infected discharge to another person’s face (Figure 39.2a).
  • An infected person touching his/her eyes and then touching another person on the face or directly on their eyes (Figure 39.2b).
  • Clothing used to wipe infected eyes (Figure 39.2c), and then contaminating the eyes of another person, for example if it is used as a towel.
Transmission of trachoma
Figure 39.2  Transmission of trachoma by (a) flies, (b) eye contact with contaminated hands, (c) eye contact with contaminated clothing. (Source: WHO, 1993, Primary Healthcare Level Management of Trachoma)
  • Based on your study of earlier parts of this Module, the infectious agents of which other diseases may be transmitted by house flies?

  • The infectious agents causing diarrhoeal diseases, such as dysentery and acute watery diarrhoea, can be transmitted by flies (Study Sessions 32 and 33).

39.1.3  How common is trachoma in Ethiopia?

Trachoma is a very common disease in developing countries, including Ethiopia – particularly in dry rural areas. About 80 million people in the world suffer from trachoma, of whom about eight million have become visually impaired. There are currently more than 238,000 people with blindness due to trachoma in Ethiopia. Trachoma is very common among children in certain parts of the country; for example, more than 50% of Ethiopian schoolchildren have had trachoma infections at some time. Without proper treatment, many of them will suffer severe eye problems in later life.

39.1.4  Clinical manifestations of trachoma and disease progression

Important!Wash your hands thoroughly with soap and water before and after each eye examination!

As a Health Extension Practitioner you should examine affected children and adults to identify the severity of the trachoma. Use your clean hands and a pen to turn the eyelids upwards, so you can see the conjunctiva, as illustrated in Figure 39.3.

Examination of the conjunctiva
Figure 39.3  Examination of the conjunctiva inside the upper eyelid for signs of trachoma. (Source: WHO, 1993, Primary Healthcare Level Management of Trachoma)

The clinical manifestations of trachoma have been classified by the World Health Organization (WHO) into five grades indicating how far the disease has progressed. The first grade is the earliest manifestation of the infection, and the fifth grade is permanent eye damage causing sight loss and leading eventually to blindness. It is important for you to know the signs that indicate these grades, because the actions you take when you see a person with suspected trachoma depends on correct grading. The names and code letters of the five grades are given in Box 39.1; they are each described in detail below the box.

Box 39.1  The five grades of trachoma progression

First grade = Trachomatous follicles (TF)

Second grade = Trachomatous inflammation (TI) or (TF+TI)

Third grade = Trachomatous scarring (TS)

Fourth grade = Trachomatous trichiasis (TT)

Fifth grade = Corneal opacity (CO)

Trachomatous follicles (TF)

The first and earliest trachoma grade is characterised by the presence of five or more trachomatous follicles in the conjunctiva inside the upper eyelid. They are round, slightly raised, whitish areas of at least 0.5 mm in size (Figure 39.4). Trachomatous follicles should not be confused with trachoma scars, which are flat (see Figure 39.5 below), or the normal eyelash follicles on the edge of the eyelids. Other signs that you may notice are redness and swelling of the conjunctiva as a result of inflammation caused by the bacterial infection.

Trachomatous follicles in the upper conjunctiva
Figure 39.4  Trachomatous follicles in the upper conjunctiva of a child with early signs of trachoma. (Photo: WHO at
Trachomatous inflammation (TF+TI)

The second grade is when profound inflammation occurs in more than half of the upper conjuctiva, which is red, thick and swollen, and has many trachomatous follicles (Figure 39.5). In severe cases, the blood vessels of the eyelids may not be visible due to the swelling of the conjunctiva.

Trachomatous inflammation with trachomatous follicles
Figure 39.5  Trachomatous inflammation with trachomatous follicles. (Photo: WHO, sources as in Figure 39.4)
Trachomatous scarring (TS)

In time, the inflammation resolves and the follicles are replaced by scars on the conjunctiva, which appear as small glistening lines or stars, and later may become flat, thick, white bands (Figure 39.6). This is the characteristic third grade of trachoma progression.

Scars in the conjunctiva
Figure 39.6  The white bands and lines are scars in the conjunctiva of the inner eyelid. (Photo: WHO, source as in Figure 39.4)
Trachomatous trichiasis (TT)

The scars gradually cause the eyelashes to turn inwards, and at least one eyelash rubs on the cornea. This sign is called trichiasis (pronounced ‘trik-eye-assis’) and is the fourth grade of trachoma severity. You can see in Figure 39.7 that many of the eyelashes are turned inwards and rub the cornea when the person blinks. This is painful and distressing for the person and it gradually damages the cornea.

Turned in eyelashes rubbing the cornea
Figure 39.7  Eyelashes rubbing the cornea. (Photo: WHO, source as in Figure 39.4)
Corneal opacity (CO)

A healthy cornea appears black where it covers the lens at the front of the eye. In the fifth and most severe grade of trachoma, the cornea becomes white and opaque (not transparent) as in Figure 39.8. This is known as corneal opacity.

Corneal opacity, damaged cornea becomes white
Figure 39.8  Corneal opacity due to chronic trachoma. (Photo: WHO, source as in Figure 39.4)
  • What effect will corneal opacity have on the person’s sight?

  • Light cannot pass easily through the opaque cornea, so the person’s sight will be severely impaired and total blindness may result.

  • How can you tell the difference between trachomatous follicles and trachomatous scars in the conjunctiva?

  • Follicles are raised and round and at least 0.5 mm in diameter. Scars are lines or bands and are flat.

39.1.5  Prevention and control of trachoma

There are four major components for the prevention and control of trachoma at community level, which are represented by the letters SAFE (see Box 39.2 and the details below the box).

Box 39.2  SAFE strategy for the prevention and control of trachoma

S = Surgical treatment for trichiasis to stop eyelashes rubbing the cornea

A = Antibiotic treatment of active cases of trachoma by tetracycline 1% ointment applied to the eyes

F = Faces and hands washed regularly to prevent infection spreading

E = Environmental sanitation and safe water supply.

Surgical treatment

A simple surgical procedure can save a patient from becoming blind. Surgery can be carried out at the health centre by trained nurses and may simply involve turning out the eyelashes that are scarring the cornea. Your role is to reassure and refer patients with Grades 3 to 5 (i.e. trachomatous scarring, trachomatous trichiasis, or corneal opacity) for immediate surgery. Explain that the operation is very simple, quick and safe, and it will greatly reduce the discomfort in their eyes and prevent further damage from occurring.

Antibiotic treatment

You are expected to treat grade 1 and grade 2 active trachoma (i.e. people with trachomatous follicles and trachomatous inflammation in at least one eye) in the community. You should show parents how to administer tetracycline 1% ointment onto the conjunctiva inside the eyelids twice every day for six weeks (Figure 39.9a and b). If you identify two or more family members with trachoma, treat the whole family.

Treating a child with tetracycline eye ointment
Figure 39.9  (a) Positioning a child to apply tetracycline eye ointment. (b) Placing the ointment inside the lower eyelid. (Diagrams: Dr Radmila Mileusnic)

If you are informed by the District Health Office that trachoma is a major concern, you may be advised to treat all the children in your community as a preventive measure. If this is the case, treat all children with tetracycline eye ointment for five consecutive days in a month, and repeat the same procedure for six consecutive months. Alternatively, a doctor may prescribe the oral antibiotic azithromycine (20 mg/kg bodyweight) as a single dose in place of tetracycline to treat the whole community.

Face washing

Educate all families, particularly mothers of children (Figure 39.10), by going house to house to teach them the importance of regular washing of face and hands, ideally using soap. Go to schools to teach children there in a large group that washing regularly prevents the transmission of trachoma from person to person. Everyone should learn the habit of washing their hands with soap and water in the early morning before they touch their eyes, before and after eating or preparing food, and after using the latrine.

Women teaching children how to wash their hands and faces
Figure 39.10  Women teaching children how to wash their hands and faces in Wonji, Ethiopia. (Photo: WHO TDR Image Library, image 9400962/Martel)
Environmental sanitation

Detailed procedures of personal hygiene and sanitation are given in the Module on Hygiene and Environmental Health.

Educate every family to dispose of their household rubbish in a pit dug away from their home (Figure 39.11). Garbage and other dirty materials can be buried using spades or other locally made tools. The waste materials should be covered with soil or burnt inside the pit. Educate adults and children to keep their surrounding environment clean and free from rubbish and animal dung, to avoid encouraging the breeding of flies. Animals should be penned away from the house at night. Encourage everyone to use latrines and a safe water supply to prevent disease transmission by flies and dirty hands. Latrines should be properly covered after use.

Waste disposal in a pit
Figure 39.11  Waste disposal in a pit away from the house. (Source: WHO, 1993, Primary Healthcare Level Management of Trachoma)

Now read Case Study 39.1 and then answer the question that follows it.

Case Study 39.1  Mrs Halima asks about her child’s eye problems

Mrs Halima lives in a remote rural village in Wollo. Her ten-year-old son has had eye discharges for the last three years, which seem to be getting worse. During the last one year, his eyes frequently weep tears and look swollen and red, and the boy complains that his eyes are sore. Mrs Halima has taken him to several traditional healers, but his eye problems have not been cured. She tells you she believes that her child’s eye problems are related to supernatural powers and no treatment can help him.

  • What do you advise Mrs Halima and what action do you take for the child?

  • Explain to the mother that her son’s eye problems are a disease called trachoma, caused by bacteria. Tell her it can be cured using medicine in the eyes or a very simple operation to stop the child’s eyelashes turning inwards and rubbing his eyes. Examine the boy’s eyes and decide what grade of trachoma the disease has reached. If the grade is TF or TF+TI, treat him with tetracycline eye ointment (1%), and show the mother how to do it twice a day for the next six weeks. Follow up his progress regularly every week. If the boy needs surgery, inform the mother and refer him to the health centre immediately.

39.2  Scabies

Scabies is not a serious condition, but it is very common in poor communities and it may severely impair the quality of life of affected children.

39.2.1  What causes scabies and how is it transmitted?

Scabies (ekek in Amharic) is a parasite infestation of the skin caused by microscopic mites, Sarcoptes scabiei (Figure 39.12). These tiny animals are spread principally by direct skin-to-skin contact (e.g. during close physical contact between children and parents, or during sexual intercourse), and to a lesser extent through contact with infested clothes and bedding.

Sarcoptes scabiei
Figure 39.12  Sarcoptes scabiei, stained and viewed through a microscope. (Photo: CDC at

Male and female mites mate on the surface of the person’s skin. The female burrows into the skin, depositing eggs in the tunnel behind her. After the eggs are hatched, larvae migrate to the skin surface and eventually change into the adult form. An adult mite can live up to about a month on a person, but they survive only two to three days once away from the human body. Individuals who become infested with scabies mites for the first time usually develop symptoms after four to six weeks, but they can still spread the mites during this time. If someone is cured of scabies, but acquires the mites again later, the symptoms appear much more quickly, within days.

39.2.2  How common is scabies in Ethiopia?

Scabies mites are found worldwide, in all communities and climates. There are thought to be about 300 million cases of scabies in the world each year. In Ethiopia, as elsewhere, scabies is common where there is poverty, poor water supply, poor sanitation and overcrowding.

39.2.3  Clinical manifestations of scabies

The first clinical manifestation of scabies is severe itching of the skin, particularly at night. The characteristic raised red pimples on the skin that develop later are due to an allergic response to the mites. You may also be able to see the threadlike burrows in the skin made by egg-laying female mites. In infants, the palms, soles, face and scalp are most often affected (Figure 39.13a). In older children and adults the rash is most often found in the spaces between fingers and toes, wrist (Figure 39.13b), armpits, ankles, navel, ‘belt line’, groin, buttocks, genitals in men and breasts in women.

Scabies sores on feet and wrist
Figure 39.13  Scabies sores on (a) the soles of a baby’s feet, (b) an adult’s wrist. (Photos: DermNet, Dartmouth Medical School, USA, at

39.2.4  Treatment and prevention of scabies

A chemical called benzyl benzoate lotion (BBL, 25% solution) is used for the treatment of scabies. In adults, the lotion should be applied to the whole body, including the neck, face and ears – but taking care not to get it into the eyes, nose or mouth. Use a cotton swab to squeeze the lotion under the ends of the fingernails and toenails, where mites can hide. Tell the person not to wash! Repeat the treatment the following day and advise the patient not to wash for another 24 hours.

Children should also be treated with BBL, but the advice is to apply the lotion every day for three days; on each day leave the lotion on the child’s body for 13 hours, then wash it off.

Other people who have been in close contact with a child or adult with scabies should also be treated with BBL to avoid re-infection, and all clothes and bedding should be thoroughly washed with hot water and dried in sunlight (Figure 39.14).

Sunlight helps to kill infectious agents in washed clothes
Figure 39.14  Sunlight helps to kill infectious agents in washed clothes and bedding dried in fresh air. (Photo: Basiro Davey)

Education on prevention of scabies should focus on explaining the transmission of the itchy mites and good personal hygiene, such as bathing and washing clothes frequently. The main control measures are early diagnosis and treatment of patients and contacts.

  • How do you tell the difference between the skin manifestations of scabies and onchocerciasis? (Think back to Study Session 37.)

  • Severe itching of the skin is the common characteristic of both scabies and onchocerciasis. However, onchocerciasis has additional symptoms such as loss of skin colour and nodule formation, whereas scabies rashes are raised red pimples and flaky skin. Scabies occurs mainly in conditions of poverty and overcrowding where the mites can easily breed; whereas onchocerciasis is common in south-west Ethiopia in communities living near the fast-flowing water required by the insect vector (blackflies).

39.3  Podoconiosis

Podoconiosis (podoconiosis is pronounced ‘poh-doh-koh-nee-oh-sis’) is a type of elephantiasis (swelling of the limbs) that is common in highland Ethiopia (woina dega or dega) in areas of red clay soil, usually at high altitudes. There is a great deal of misunderstanding about the disease in affected communities. Some people think it is caused by treading on a snake or frog, others that it is a curse or form of punishment. In reality, podoconiosis (Figure 39.15) is a reaction in the body to very small soil particles that have passed through the skin of the feet. The swelling begins in the feet and progresses up the legs, and both feet are usually affected.

Podoconiosis is swelling and deformity of the feet and ankles
Figure 39.15  Podoconiosis is swelling and deformity of the feet and ankles caused by reactions in the body to particles of red clay soil getting into the skin. (Photos: Gail Davey)

Unlike other types of elephantiasis, podoconiosis is not caused by any bacteria, viruses or parasites. It cannot be transmitted between people, so close contact with someone who has podoconiosis is totally safe. You may wonder why you are learning about it in a Module on Communicable Diseases; there are two reasons. First, severe podoconiosis looks a lot like lymphatic filariasis, which you learned about in Study Session 37. It is important to know the difference between these diseases because there are differences in their treatment. Second, how you teach patients to reduce the disability due to podoconiosis is exactly the same as the methods you have already learned about for lymphatic filariasis.

39.3.1  Distinguishing podoconiosis from lymphatic filariasis

The outward appearance of legs and feet affected by podoconiosis and lymphatic filariasis is very similar – you can’t tell the difference just by looking. But there are some questions you can ask the patient that can help you to decide which diagnosis is most likely to be correct.

Where does the patient live?

If the patient lives more than about 1,200 metres above sea level, then the leg swelling is likely to be due to podoconiosis. This is because the mosquitoes that transmit lymphatic filariasis cannot survive above this altitude – it is too cold at night. If the patient has always lived in dega or woina dega areas, or does not live in zones where lymphatic filariasis is known to be prevalent, then you should diagnose the leg swelling as podoconiosis.

Where did the disease start and what body parts are affected?

If it started in the feet and both feet/legs are affected, then the diagnosis is likely to be podoconiosis. If the swelling began in the groin and spread downwards, if only one leg is affected (look back at Figure 37.21a), and/or the lymph nodes in the groin are enlarged – then the disease is likely to be lymphatic filariasis.

  • Can you suggest why it is important to distinguish between podoconiosis and lymphatic filariasis? (Think back to Study Session 37.)

  • Podoconiosis is not infectious (it is caused by soil particles), so patients don’t need drug treatment because there is no infectious agent to kill; there is no vector so their houses don’t need to be sprayed to kill mosquitoes (unless, of course, malaria is endemic in the area). Treating podoconiosis with the drugs used to treat lymphatic filariasis would be a waste of precious resources and would not cure the disease.

    Malaria can be transmitted by mosquitoes in communities up to 2,000 metres above sea level. See Study Session 5 in Part 1 of this Module.

39.3.2  How does podoconiosis affect people?

There is a major similarity in the experiences of people with podoconiosis and lymphatic filariasis, as we already mentioned in Study Session 37. They often face severe stigma and rejection by their communities. They may be forced out of school, or even rejected by their church, mosque or idir. Other people may be reluctant to eat with them or associate with them in other ways. Marriage for people in affected families may be restricted to people from other affected families. Many of these social problems arise because people mistakenly fear that podoconiosis is infectious, and that they may catch it from patients.

People with swollen legs due to lymphatic filariasis face the same problems as people with podoconiosis.

In addition to this social stigma, people with podoconiosis often find it difficult to do physical work because their legs are heavy and uncomfortable. They often become very poor as a consequence of being unable to farm or take produce to market. Whole communities are also poorer because people with podoconiosis cannot work on their farms. As a country, the WHO estimates that Ethiopia loses US$200 million each year because of the work that people with podoconiosis are unable to do.

39.3.3  Treatment of podoconiosis.

Most people do not know that leg swelling from podoconiosis can be treated – but it can! Using simple foot hygiene, ointment, elastic bandages, socks and shoes, brings improvement to more than nine out of ten patients. They can manage their own foot care if you show them what to do. The basic steps of treatment will be familiar from Study Session 37, but are summarised again briefly here:

  1. Foot hygiene. First soak the feet for 20 minutes in a basin of cold water into which half a capful (about 10 drops) of berekina (bleach) have been added.
  2. Then wash the feet carefully using soap and clean cold water (Figure 39.16a). Dry between the toes with a clean cotton cloth.
  3. Rub a small amount of ointment or oil into the skin after drying.
  4. For patients with softer swelling of the legs, elastic bandages are useful. Show the patient how to apply the bandage from the toe to the knee, with the leg raised (Figure 39.16b).
    Washing feet and elevating the legs
    Figure 39.16  (a) Foot hygiene and (b) elastic bandages and raising the legs can greatly improve the symptoms of podoconiosis. (Photos: Gail Davey)
  5. Encourage the patient to perform exercises to improve their circulation, such as toe points, ankle circles and calf raises, two or three times per day.
    Houses with earth floors should be covered with mats
    Figure 39.17  Houses with earth floors should be covered with mats to prevent soil particles penetrating bare feet. (Photo: Janet Haresnape)
  6. Raise the affected legs whenever possible by raising the foot end of the bed, or resting the foot on a stool when sitting.
  7. Clean socks and closed shoes are vital in preventing further exposure to the soil. If local houses have floors made of earth (Figure 39.17), the floor should be covered with mats.
  • What do you now know about podoconiosis that may also help to break down the stigma that many patients face?

  • It is not infectious. Podoconiosis can be treated using simple hygiene measures. It can be prevented through regular use of shoes.

Experience in Southern Ethiopia has shown that more than 90% of patients with podoconiosis can be successfully treated without need of referral for care within the government health system. Communities can handle most of the problems that podoconiosis patients have without need for formal healthcare. Seeing young men and women fully treated (Figure 39.18) has a positive impact on the communities that knew them previously as patients.

These young women have been successfully treated for podoconiosis
Figure 39.18  These young women have been successfully treated for podoconiosis. Now they have found work as hairdressers. (Photo: Gail Davey)

39.3.4  Podoconiosis-plus: problems that need urgent referral

Some podoconiosis patients will develop symptoms that need urgent referral for further care at a health centre or hospital. Here are some of the warning signs:

  • Red hot leg. Sometimes, people with podoconiosis develop bacterial superinfection (‘added infection’ by bacteria that usually live on the skin) in the swollen leg. They report aching pain and increased heat and swelling in the leg, fevers or chills, and sometimes headaches. They need antibiotics to control the infection, and painkillers.
  • Open wounds. After an injury, a person with podoconiosis is more likely to develop an open wound that may not heal easily. Careful wound care using clean techniques and local dressing materials will be needed, most likely at a health centre.
  • Deep fungal infection (a fungus has taken root deep in the swollen tissues). The patient may notice black dots on the surface of the skin. They need hospital treatment.
  • Skin cancer. Looking carefully, you will see an ulcer with a rolled edge (like rolled injera). This needs hospital treatment.

39.3.5  Prevention of podoconiosis

Here is the good news – because the disease is a reaction to soil particles, wearing shoes every day to protect the feet from the soil will prevent it completely! So if children wear shoes all the time, the next generation will not suffer from podoconiosis.

Summary of Study Session 39

In Study Session 39, you have learned that:

  1. Trachoma is one of the leading causes of blindness in Ethiopia; it is due to infection with Chlamydia trachomatis bacteria, transmitted from person to person by flies, on hands and clothing, and sometimes also from mother to newborn if the bacteria are in the birth canal.
  2. Patients with active trachoma (grade TF or TF+TI) should be treated at community level with tetracycline eye ointment. More severe grades of trachoma should be referred for specialist treatment, often involving simple surgery to stop the eyelashes from rubbing the cornea.
  3. Scabies is a severe skin inflammation caused by reactions to a microscopic parasitic mite that burrows into the skin. The irritation can seriously impair the quality of life of affected children.
  4. Good personal hygiene, particularly washing the face, body and clothes with soap and clean water, and environmental hygiene, including disposal of rubbish and other waste, and using latrines, are important ways to prevent trachoma and scabies.
  5. Podoconiosis is a non-infectious type of elephantiasis (swollen leg) caused by reactions to particles of red clay soil entering the skin. It can be prevented if children grow up wearing shoes all the time.
  6. People with podoconiosis can be successfully treated in the community using simple foot hygiene, ointment, elastic bandages, socks and shoes. Sometimes, patients with podoconiosis need urgent referral for treatment of ‘superinfection’ with bacteria or fungi, open wounds, or skin cancer.
  7. If you educate people that podoconiosis is not infectious and can be treated and prevented, the stigma and rejection that patients often experience can be resolved.

Self-Assessment Questions (SAQs) for Study Session 39

Now you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering the following questions. Some of the questions test your knowledge of earlier study sessions in this Module. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.

SAQ 39.1 (testing Learning Outcomes 39.1, 39.2, 39.3 and 39.4)

Which of the following statements is false? In each case, explain what is incorrect.

A  Zinash is a 16-year-old girl who has had eye problems for the last four years. There are white bands inside her swollen red eyelids. You should immediately refer her to hospital.

B  A newborn with red and swelling conjunctiva should be treated by putting tetracycline ointment into the eyes.

C  Corneal opacity is reversible through treatment with tetracycline ointment.

D  Scabies can be treated successfully with tetracycline ointment.

E  The SAFE strategy for preventing trachoma stands for surgical treatment, antibiotics, face washing and environmental sanitation.

F  Disability resulting from podoconiosis and lymphatic filariasis can be reduced by foot and leg hygiene, exercising the affected part and raising the legs when sitting or sleeping.

G  Trachoma, scabies and podoconiosis are all communicable diseases found in conditions of poverty, overcrowding and poor access to clean water and sanitation.


A is true. Zinash has scarring of the conjunctiva (white bands inside the eyelids), i.e. trachoma grade TS. Therefore, she should be referred to hospital for surgical treatment.

B is true. A newborn with red and swollen conjunctiva could have got the infection from its mother during birth and should be treated with tetracycline eye ointment (1%).

C is false. Corneal opacity is a permanent type of damage and cannot be improved by treating with tetracycline ointment.

D is false. Scabies is caused by a parasite and can’t be treated by tetracycline ointment, which is used to treat grade TF and TI trachoma. A child with scabies should be treated using BBL lotion.

E is true. The SAFE strategy for preventing trachoma stands for surgical treatment, antibiotics, face washing and environmental sanitation.

F is true. Disability resulting from podoconiosis and lymphatic filariasis can be reduced by foot and leg hygiene, exercising the affected part, and raising the legs when sitting or sleeping.

G is false. Podoconiosis is not a communicable disease – it is caused by contact with red clay soils, not an infectious agent. However, trachoma and scabies are communicable diseases found in conditions of poverty, overcrowding and poor access to clean water and sanitation.

SAQ 39.2 (testing Learning Outcomes 39.3 and 39.4)

If you see a girl with discharge coming from her eyes and flies landing on her face (Figure 39.19), what should you advise her family?

A girl with eye discharges and flies on her face
Figure 39.19  A girl with eye discharges and flies on her face.

The family of the girl should be educated about face washing with soap and clean water every day to remove the eye discharges. Tell them that the presence of eye discharge and poor personal hygiene will transmit trachoma bacteria to other people through flies landing on the face, and dirty hands and clothing touching the eyes.

SAQ 39.3 (testing Learning Outcomes 39.1, 39.2 and 39.3)

Name at least three communicable diseases that can result in blindness. In each case, briefly state the cause of the eye problems.


Measles, onchocerciasis and trachoma are the three major communicable diseases that can cause blindness. In Study Session 3 of this Module, you learned that measles can cause blindness, particularly among malnourished children who are lacking vitamin A. In Study Session 37 you learned that onchocerciasis can affect the eyes and cause so-called ‘river blindness’ because the insect vector (blackflies) needs fast-flowing water to breed. Trachoma causes blindness due to corneal damage resulting from bacterial infection of the conjunctiva.

SAQ 39.4 (testing Learning Outcomes 39.2, 39.3 and 39.4)

How many diseases can you remember learning about in this Module where the symptoms are at least partly caused by allergic reactions by the patient’s immune system to foreign material getting into the body?

In each case, briefly describe the foreign material.


Several of the communicable diseases you have learned about in this Module have clinical manifestations that are due to allergic reactions by the patient’s immune system to foreign material introduced into their bodies. The foreign material may be the infectious agent itself: for example, in tuberculosis, leprosy, schistosomiasis, leishmaniasis, onchocerciasis, lymphatic filariasis and trachoma – or the allergic reaction may be to scabies mites. You may also have noted that the allergic reaction to body lice bites causes itching and scratching, which enables the infectious agents of relapsing fever and typhus to enter the body through breaks in the skin. Podoconiosis is due to an allergic reaction to red clay soils penetrating the skin of bare feet.