6 Important health problems and their causes
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- Unit 12: Infectious disease
- Case studies
- Unit 13: Non-communicable disease
- Case studies
Unit 12: Infectious disease
When you have completed this unit you should be able to:
- Define epidemic, pandemic and endemic diseases.
- Explain where epidemics come from and how they spread.
- Explain the strategies for controlling epidemics.
- Prepare your hospital for an epidemic.
- Explain how antibiotic resistance occurs and how it can be prevented.
12-1 Why are infectious diseases becoming important again?
Rapid advances were made in the fight against infectious disease in the 20th century. People understood how microbes were spread and this led to improvements in sanitation in towns and cities, and the introduction of hand washing in healthcare providers. From about 1950 onwards, penicillin became widely available, followed by many other antibiotics, and effective treatment for tuberculosis was developed. Immunisation against most of the deadly childhood illnesses was also introduced around this time. Towards the end of the 20th century, it seemed that major epidemics of infectious disease would become a thing of the past. We now know that is not true, and infectious diseases are likely to be an increasing concern in the next few decades for 2 reasons:
- The emergence of new epidemics of infectious disease, most of which are viral.
- The emergence of bacteria that are resistant to antibiotics and commonly cause outbreaks in hospitals.
Both of these are related to human and social factors.
12-2 What is an epidemic and what is an outbreak?
An epidemic is the occurrence of disease where the number people affected is in excess of what would normally be expected. There does not have to be a particular number of cases. For example, with a very rare infectious disease like bubonic plague, only a few cases are sufficient to call it an epidemic. Most epidemics involve many cases as seen in the past with measles.
A related term is an outbreak, which has the same definition as an epidemic, but we use the term outbreak when numbers are smaller and the cases occur in a more limited area. An example would be scabies in a school.
Epidemic means that more than the expected number of people are affected by a disease.
12-3 What is a pandemic?
When an epidemic affects many countries in the world, we may call it a pandemic. The important pandemics of recent years are HIV, various strains of influenza such as Swine Flu and Avian Flu, and the Severe Acute Respiratory Distress Syndrome (SARS). All of these examples are called pandemics because they have spread over many countries. An epidemic of Ebola in West Africa in 2014 also caused great concern but because it did not spread outside 3 countries in the same region it was not called a pandemic.
12-4 What does endemic mean?
The word endemic is used to describe the occurrence of an infectious disease in a particular area only where the number of cases is stable and predictable. Tuberculosis, Herpes simplex and tick bite fever can be described as endemic diseases, as long as there is no sudden increase in the number of cases.
- When an infectious disease occurs at a stable rate that is persistently high, it may also be called hyperendemic. Tuberculosis in South Africa can be described as hyperendemic.
12-5 Where do epidemic diseases come from?
Epidemics frighten people because they seem to appear from nowhere, affect or kill a lot of people, and then disappear. The science of epidemiology tells us how this happens. Microbes, such as bacteria and viruses, reproduce very quickly and often mutate (this means that their genetic code changes a little, together with their behaviour). A mutated microbe may be better adapted to multiply and survive in a particular environment and may also be able to infect other species. Both cause the infection to spread rapidly.
Many of the microbes that cause human epidemics live in animals, where they appear not to cause any great harm. This is called the “animal reservoir” of a microbe. Most modern epidemics are started when humans come into close contact with microbes in the animal reservoir. An epidemic begins when microbes have mutations that allow them to “cross the species barrier”. The infected humans then transmit the microbe to other humans. Increased contact between humans and the animal reservoir happens when humans start living, farming, or looking for food in areas where there has not been a great human presence. For example:
- A similar virus to HIV is found in chimpanzees and it seems likely that the virus came into contact with humans when chimpanzees were hunted as bush meat and the chimpanzees virus crossed the species barrier.
- The animal reservoir for Ebola is probably fruit bats which are also used as bush meat.
- Birds are the natural reservoir of influenza, and the virus passes from the wild bird population to domestic poultry and then to humans.
Most new epidemics come from an animal reservoir.
12-6 How do epidemics spread?
Most epidemics are spread either by droplets in the air from coughing or sneezing, like influenza, or from direct contact with body fluids such as blood or saliva, such as Ebola. Whether or not an infection starts spreading to many other people depends on the number of other people each case infects. Each infected person needs to cause (on average) infection in more than one other person in order for the infection to spread, otherwise it will just die out.
For an epidemic to increase and spread, each case must on average infect more than one other person.
12-7 What determines the severity of an epidemic?
The number of people who become ill in an epidemic is affected by:
- The pathogenicity of the organism. This is the ability of a microbe to cause disease in a host.
- The virulence of the micro-organism. This is the infectiveness, or how “easy it is to catch”.
- The number of susceptible people each case comes into contact with. This depends on:
- Human and social factors: how people travel about, how they come together and how they interact when they do meet (crowded homes and public spaces).
- The quality of healthcare services. If people do not trust health services, they may travel to seek care elsewhere, or infected family members may be cared for at home rather than entering an isolation unit.
- How susceptible other people are to being infected. This depends on their resistance and on the type of contact. For example spending time in a confined space such as a bus increases the risk of a droplet transmitted disease. Transmission may also happen because a person has not taken precautions such as the wearing of a mask.
The epidemic initially grows, and then starts to die out as the microbe encounters fewer susceptible people, either because those who recover from the illness become resistant, or because the population number falls as a result of so many deaths. Transmission between people may completely stop, or the disease may become endemic and continue to occur at a lower rate as has happened with HIV for example.
The number of other people infected by each person with the disease is determined by how infectious the microbe is and also how many susceptible people that infected person comes into contact with.
12-8 How can epidemics be prevented at their source?
To prevent human transmission at source, it is important to understand where these diseases come from, and this may mean trying to control the way in which humans come into contact with animals. Many of the recent influenza pandemics have originated in East Asia and large, live poultry markets in China seem to be an important reservoir. Controlling or closing poultry markets has had an impact on the spread of influenza, but unfortunately also an impact on people’s livelihoods. Controlling the bush meat trade in Africa is more difficult.
Not all epidemics start as a result of human contact with animals. Others may be waterborne, such as cholera, or insect borne such as yellow fever. Improved sanitation and the control of mosquitoes may reduce outbreaks of these diseases.
Many epidemics can be controlled at source by trying to stop humans coming into contact with microbes in the animal reservoir and protecting water supplies.
12-9 What is the difference between isolation and quarantine?
Once microbes have come into contact with humans and caused infection, it is possible to reduce their spread between humans by reducing the number of susceptible people each infected person comes into contact with. This might involve isolating individuals who are showing symptoms and signs of disease. Isolation means keeping sick people apart from others who are well. If they have care needs, special infection prevention and control techniques should be used to look after them.
If somebody has been in contact with the disease, they may have been infected without yet showing symptoms or signs of disease. When they are required to stay away from others for a period of time in case they develop and possibly spread the disease, it is called quarantine.
Isolation means stopping people with symptoms or signs of disease coming into contact with uninfected people. Quarantine involves observing symptom free people who have come into contact with infected people to see if they develop disease.
12-10 What other public health measures are used to reduce contact between infected and susceptible people?
Other methods include:
- Actively looking for people who have been in contact with an infected person and may themselves have become infected. This is called contact tracing. It is an important part of TB control.
- Reducing contact between people without knowing exactly who has been infected. This can be done, for example:
- By closing schools during major epidemics. There is some evidence that this does work, although it can be very disruptive for families. This was important in the past during polio epidemics.
- In order to limit the spread of infections between countries, advising people not to travel (travel advisories) or travel restrictions are sometimes introduced. Screening is done at airports, although there is limited evidence of how effective this is. It is also important to note that travel restrictions can stop treatment and care reaching affected areas and can make an epidemic worse.
- Immunisation is a very important way of reducing the number of susceptible people. Although there are effective vaccines for many diseases such as polio or measles, they have not yet been developed for some of the more recent epidemics such as HIV and Ebola.
It is possible to reduce the spread of disease from human-to-human by isolating infected cases, by observing people who might be infected, by looking for contacts, and by immunising where possible.
12-11 How can a health facility prepare for epidemics?
Many of the infectious diseases presenting to facilities in South Africa, such as TB and HIV, are well-known and most service providers are able to take the necessary precautions and deal with them. Occasionally, there are risks from less familiar infectious diseases and we must be prepared for them. These risks are likely to come from acute respiratory viruses, such as the various new types of influenza, or from viral haemorrhagic fevers such as Congo fever and Ebola. Although epidemic management will vary according to the specific threat, there are certain principles that are worth mentioning:
- Healthcare providers should be alert to the possibility of an important infectious disease, particularly when a patient with undiagnosed fever has a history of travel, or if more than one person with a fever is not responding to treatment as expected. The medical team is an important part of the surveillance system for emerging infectious diseases.
- If new cases of an important infectious disease have been identified elsewhere, it is important to find out the set of symptoms and signs that characterise the disease. This clinical description of the disease is called the case definition. Knowing what to look for means that:
- Cases will be recognised and identified early.
- Facilities will be able to act immediately and appropriately.
- There will not be unnecessary concern that each person coming through the door with a fever might be a serious infection hazard.
- With important epidemics, there needs to be a response plan beyond an individual institution. Experts in infectious disease and public health will need to make a plan about where these cases must go, and how smaller hospitals should treat suspected cases in the meantime. You should make sure that you have a copy of these plans and understand them.
When there is a concern about an infectious disease epidemic in a country or region, it is important for clinical managers to ask for a case definition and a management plan from the district or regional public health team. This must be communicated with the rest of the health team.
12-12 What is an antimicrobial?
An antimicrobial is an agent that either kills microbes (microorganisms) or stops them growing. There are several different types of antimicrobials:
- Disinfectants are chemicals that are designed to kill microbes on non-living surfaces. Bleach is an example.
- Antibiotics are substances that kill or stop the growth of bacteria in living organisms (for example, in humans).
- Antivirals are substances that kill or stop the growth of viruses in living organisms. HIV is a type of virus called a “retrovirus”. The drugs used against HIV are called antiretrovirals or ARVs.
- Antifungals are substances that kill or inhibit the growth of fungi in living organisms An example is mycostatin to treat moniliasis (thrush).
An antimicrobial kills or stops the growth of microbes.
12-13 What is antimicrobial resistance?
Antimicrobial resistance refers to changes in the characteristics of a microbe so that antibiotics, antivirals or antifungals are no longer effective in killing it or stopping its growth.
Most microbes multiply rapidly, and slight changes in their genetic code during this multiplication (“mutations”) give rise to offspring with different characteristics. This means that these microbes can adapt to new environments where they can survive and continue to multiply:
- Viral epidemics can occur when mutations help animal viruses to “jump the species barrier” and spread to humans. The same process of mutation means that viruses can become resistant to antivirals. There is also growing concern about resistance of HIV to antiretroviral drugs in people who do not regularly take their medication correctly.
- Bacteria also mutate and as a result survive antibiotic challenges and continue to reproduce. This is the explanation behind antibiotic resistance, where bacteria develop the ability to survive in spite of antibiotics.
- Fungi can also become resistant to antifungals.
12-14 What factors favour the development of antibiotic resistance?
Resistance is more likely when antibiotics are overused, because the more often bacteria encounter an antibiotic, the more likely it is that an antibiotic will meet mutated bacteria that are resistant to it. When this happens, the resistant bacteria have an advantage and continue to spread and multiply in spite of the antibiotic and becoming the dominant (common) type. There are 2 important reasons for the development of antibiotic resistance:
- The use of antibiotics in farm animals to increase food production in agriculture has contributed to this problem.
- Doctors overprescribe antibiotics. If a patient attends a doctor with a cough it can be quite difficult to resist the pressure by the patient to prescribe an antibiotic even when it is not necessary for a viral infection. The patient feels he has not paid a consultation fee in order to be reassured. Unfortunately this inappropriate use of antibiotics does cause problems in the long-term.
- Antibiotics are extensively used for sick pets and farm animals in veterinary practice. As with treating people, the indication for an antibiotic is often questionable.
Resistance is also favoured when antibiotics are taken in a way that only partially treats an infection. This is because bacteria that are partially resistant would have been killed by a full course of treatment but survive and become the dominant type. This often occurs because:
- People tend to stop taking antibiotics as soon as they feel better.
- In some countries people buy only the amount of antibiotic they can afford from a market or pharmacist even if it is insufficient for a full course.
The incorrect use of antibiotics is the main reason why antibiotic resistance develops.
12-15 Why is resistance a problem when new antibiotics can be developed?
Although the pharmaceutical industry continues to produce a stream of new drugs to replace current antibiotics that no longer work, resistance remains a very big concern because:
- The new drugs are expensive.
- Microbes may also become resistant to them.
- There may come a point when scientists are not able to produce new drugs fast enough.
12-16 Why is a hospital-acquired infection often serious?
The most resistant infections are “hospital-acquired infections” because these bacteria live in an environment where they are exposed to many antibiotics and have the opportunity to acquire resistance to many of them. Infections acquired in intensive care units can be resistant to just about every antibiotic available. Furthermore resistance to antibiotics can spread between different types of bacteria.
12-17 What is the doctor’s responsibility to reduce antibiotic resistance?
Because the problem of antibiotic resistance is potentially so serious, all health workers should be interested in the use of infection prevention and control, using well tested hygiene methods. “Antibiotic stewardship programmes” are hospital based programmes that promote the safe and appropriate use of antibiotics. In this way the use of antibiotics is controlled.
These approaches are described in detail in Infection Prevention and Control of the Bettercare series that is available for free online.
Bacteria develop antibiotic resistance when antibiotics are incorrectly used. Antibiotic stewardship and infection prevention and control procedures can reduce this risk.
12-18 Why is antibiotic resistant tuberculosis becoming common?
Tuberculosis is a bacterial disease that has been with humans since ancient times. Treatment first became available in the 1950s, following the development of streptomycin in 1943. Other TB drugs, including rifampicin were developed in the 1950s and early 1960s.
However, soon after a new drug entered practice, resistance to it was identified. This led to the development of multidrug treatments, so that if a patient was infected with a strain of TB that was resistant to one of the drugs, it would still be killed by at least one of the others. Using a number of antibiotics together therefore reduced the risk of developing resistance. The modern, 4 drug, 6-month treatment regimen was introduced in the 1970s. This was a highly effective treatment for TB and in the 1980s, people started to think that TB could be eradicated as smallpox had been.
What has happened instead is the re-emergence of TB as a major cause of death, particularly in low- and middle-income countries. This is partly caused by social factors and overcrowding, and by HIV, but incompletely treated TB is a serious concern. Many patients stop taking their medication once they feel better and do not complete the full course of treatment. As a result, TB that is resistant to standard drug regimens has emerged. These infections are called:
- Multiple drug resistant TB (MDR-TB); this is TB resistant to both isoniazid and rifampicin
- Extensively drug resistant TB (XDR-TB); this is TB resistant to most anti-TB drugs
There have also been reports of “resistance beyond XDR”, which some are calling “totally drug resistant TB”. Public health systems need to be organised so that people are quickly diagnosed, started on an appropriate course of treatment, and complete their treatment. In large parts of South Africa this is not happening.
Case study 1
There had been many outbreaks of Ebola virus before, but these had tended to be confined to small villages in Central Africa. In 2014 there was an epidemic that rapidly spread to several countries in West Africa and many people died. It caused some panic in Europe and North America as there was fear that Ebola might spread worldwide.
1. Why do you think that this epidemic was so much more extensive that previous epidemics?
We have no reason to believe that this virus was more virulent than those causing previous epidemics. It is likely that the rapid spread was because of human and social factors:
- Each infected case came into contact with more susceptible people. Populations are larger and more people are able to travel widely. The epidemic probably started in a remote village, but rapid spread was likely caused by infected people travelling to the cities to look for help when they became ill, or to when they tried to escape the disease.
- In West Africa during the Ebola epidemic, the health systems were in a bad state and treatment was limited. Health workers tried to place infected people in isolation, but it was known that treatment was not available and a person would die alone and be buried by strangers. For this reason, many people ran away from health facilities, and in some cases attacked health teams. Families often hid ill relatives. The lack of trust in the health system made the epidemic much more difficult to control.
Case study 2
In the United Kingdom there was an immunisation scare in the 1990s because the measles-mumps-rubella (MMR) vaccine was said to cause autism in young children. As a result many mothers decided not to have their infants immunised with MMR. In some parts of Wales, only two thirds of children were immunised. For most of the 1990s and early 2000s, there were between 0 and 3 cases of measles confirmed per year for the entire country. However in April 2013, 529 cases were reported.
1. What is the likely cause in the increase of reported cases?
As the rates of measles immunisation in infants dropped, the population of susceptible individuals grew. Eventually, there were enough susceptible individuals for each infected person to spread measles to more than one person and there was an epidemic. Further research showed no link between MMR immunisation and autism.
Case study 3
In July 2014, a Liberian patient collapsed after arriving at an airport in Nigeria and was taken to a hospital with fever and vomiting. The patient said he had malaria. Dr Stella Ameyo Adadevoh recognised the signs of Ebola. She insisted he was hospitalised and that infection control precautions taken while looking after him. He was very angry and needed to be physically restrained. Liberian officials insisted that the patient should be allowed to travel on to a coastal city but Dr Adadevoh refused them permission. The man later died of Ebola and, sadly, so did Dr Adadevoh who became infected. However, by insisting that he was isolated she stopped him carrying the disease into Lagos, a city of 18 million people and probably saved many lives.
1. Dr Adedovah insisted the patient be stopped from coming into contact with other people. Was she ordering him into quarantine or isolation?
Isolation. This person was already showing signs of disease.
Case study 4
In 1981, a cluster of 20 men in New York with Kaposi’s sarcoma was reported.
In 1982, the US Centers for Disease Control (CDC) used the term AIDS to describe the new disease. They reported nearly 600 cases in several cities and said that the incidence was doubling roughly every 6 months.
By the mid-1980s it was clear that the virus had become established in many countries across the globe. In several countries in sub-Saharan Africa, there was an explosive increase in the number of cases.
Although the number of new cases in South Africa is slowly decreasing, HIV infection continues at a predictable rate.
1. What is the best description of the state of HIV infections in South Africa currently? An outbreak, epidemic, pandemic or endemic?
HIV infections now occur at a fairly predictable rate, HIV is best described as endemic in South Africa. The other events described above are epidemics that spread to many countries to become a pandemic.
Unit 13: Non-communicable disease
When you have completed this unit you should be able to:
- List the important non-communicable diseases in South Africa.
- Explain what is meant by chronic diseases of lifestyle.
- Suggest public health measures for reducing the burden of non-communicable disease.
13-1 What is a non-communicable disease?
A non-communicable disease is a disorder which is usually chronic and cannot be passed from person to person (non-infectious).
13-2 What are the important non-communicable diseases in South Africa?
In common with many other low and middle-income countries, South Africa is experiencing a rising burden of non-communicable diseases. The important contributors are:
- Cardiometabolic diseases
- Some of the common cancers
- Chronic respiratory disease - usually as a result of smoking, TB and work related exposure to dust
- Trauma – mainly accidents on the road and violence
- Psychiatric disease – much of which goes unrecognised
- Congenital disorders
13-3 What are the “cardiometabolic” diseases?
The cardiometabolic diseases are a group of conditions associated with a particular high risk lifestyle. They consist of:
- A high blood glucose (glucose intolerance or diabetes)
- Coronary artery disease
- Peripheral vascular disease
- Hyperlipidaemia (high triglyceride and cholesterol)
- Abdominal obesity (increased intra-abdominal fat)
These conditions are grouped together because they have the same causes and often occur in the same patient. They are sometimes called “chronic diseases of lifestyle”.
Important cardiometabolic diseases include diabetes, hypertension, coronary artery disease and stroke.
- Abnormalities in metabolism such as insulin resistance with impaired glucose intolerance and hyperlipidaemia cause atherosclerotic vascular disease.
13-4 Why are cardiometabolic diseases sometimes called “chronic diseases of lifestyle”?
The “cardiometabolic diseases” are sometimes called “chronic diseases of lifestyle” because they result from a combination of:
- An unhealthy diet (high fat, sugar and salt).
- Lack of exercise.
- A patient who is often overweight or obese.
An unhealthy diet, too little exercise and obesity are the main causes of “chronic diseases of lifestyle.”
The use of the term “chronic diseases of lifestyle” suggests that the problem is one of self-control and that all that the patient has to do to become healthier is to make better lifestyle choices, but that is not quite true because:
- Dietary choices are affected by food availability, cooking facilities and family choices that may be shaped by marketing and social desirability. Preparing vegetables can be time consuming and making a balanced meal can be difficult using just one gas or paraffin burner. High fat, high sugar, high salt “fast foods” are often readily available, tasty, affordable and convenient as they do not require preparation.
- Opportunities to exercise depend on the availability of suitable open spaces, personal safety and social norms.
- The risk of becoming an obese adult and having cardiometabolic disease starts before birth.
13-5 How do factors during pregnancy affect risk of later cardiometabolic disease?
Low birth weight due to poor intrauterine growth is common in South Africa. It is often a result of poor maternal nutrition, smoking, stress and alcohol or drug use in pregnancy. The growth restricted fetus undergoes changes in the way their genes and cells function that means that they are “programmed” to save energy and survive on a low calorie diet. For thousands of years, this was a useful adaptation because the low-birth weight infant was often born into an environment of scarcity and was more efficient at storing the available energy. However, in the modern world, the low birth weight infant is exposed to high fat, high sugar, modern diets, and is more likely to become an obese adult.
It is also true that obese mothers tend to have obese infants that grow to be obese adults. Therefore both undernutrition and overnutrition during pregnancy can result in children at greater risk of cardiometabolic disease later in life.
- Low birth weight babies are “programmed” epigenetically to survive on a low energy diet and therefore are more likely to become obese adults if they have a high calorie diet.
13-6 How important are cancers in low- and middle-income countries?
Reliable cancer statistics can be hard to find from many low- and middle-income countries. Information about cancer in South Africa is collected and published by the National Cancer Registry, but this registry is out of date and not very useful. However worldwide, cancer is said to kill more people than AIDS, malaria and TB combined, with the most common cancers being lung, breast, cervical, bowel, stomach and liver cancer.
13-7 How can cancer be prevented?
Many cancers are preventable:
- Lung cancer, which is usually caused by cigarette smoking, is overall the commonest cause of cancer death in South Africa. It is the most common cancer in men, and the incidence in women is rising. In addition to lung cancer, smoking is thought to contribute to several other cancers.
- About 20% of cancer deaths in low- and middle-income countries are due to viral infections that can be prevented by immunisation. These include hepatocellular (liver) cancer from hepatitis B virus, and cervical cancer caused by the human papilloma virus.
- Many cancers can be cured if they are diagnosed at an early stage when they are still treatable. This is another form of prevention, but it requires well-organised, effective health services.
About 20% of cancer deaths in low- and middle-income countries could be prevented by immunisation.
13-8 What is the burden of chronic lung disease in low- and middle-income countries?
In low- and middle-income countries chronic lung disease is the third most common cause of death after non-communicable disease and cancer.
Three main causes of chronic lung disease in South Africa are:
- Occupational dust disease (particularly in miners)
All are preventable. We also know that chronic lung disease can be improved by good nutrition and lung exercises. Unfortunately access to both may be limited in low income countries.
- Chronic lung disease is responsible for about 10% of all DALYs in middle and low income countries.
Smoking is an important cause of chronic lung disease.
13-9 What is the burden of disease from trauma in South Africa?
The main causes of trauma death and injury in South Africa are:
- Road accidents
- Interpersonal violence
Road accident deaths are nearly twice the global average. For South African males, murder rates are 8 times the global average, and for women are 5 times the global average.
- The most recent burden of disease data are from 2000 and show that trauma was responsible for 11.5% of DALYs in South Africa.
13-10 What are the risk factors for trauma deaths?
Trauma deaths and injuries are almost always preventable. The main risk factors are:
- Road users ignoring the rules of road safety and a lack of law enforcement are major contributors to road trauma
- Gangsterism is a major reason for murder in areas such as the Western Cape, with drugs and alcohol also playing a major role nationally
- Untreated mental illness and social stressors are risk factors for suicide.
13-11 What is the burden of mental health disorders in South Africa?
The simple answer to this is that we do not know. Mental health disorders often go unrecognised and untreated because:
- There are not enough psychiatrists, psychologists and mental health facilities in the public sector.
- There is stigma attached to mental health disorders so people may not seek help.
- Mental health disorders can be “somatised” and present with physical symptoms.
- Mental health disorders, such as anxiety or depression, that present with psychological distress rather than with disordered thoughts, may be seen as “just part of life”.
However, it is estimated that 1 in 3 South Africans will have a mental or substance abuse disorder during their lifetime. Over 2% of the population will have post-traumatic stress disorder at some point in their lives. In one study, about two thirds of children had experienced a major traumatic event such as interpersonal violence directed against themselves or a loved one, and 8% met the diagnostic criteria for post-traumatic stress disorder.
A particular problem with mental health disorders is that they can last a long time, there is often delay in diagnosis and treatment and they can recur during the lifetime.
13-12 What are the risk factors for mental health disorders?
The term “mental disorder” covers a broad spectrum of conditions, and much less is known about the causes of mental disorder than is known about disease in other organs. The following are recognised risk factors:
- Social inequality, poverty, discrimination and social isolation all increase the risk of many common mental health disorders such as depression, anxiety and “somatisation” (mental stress presenting with physical symptoms).
- Not having somebody to talk to about stresses and life problems increases the risk of these common mental disorders, particularly for women.
- Violence and traumatic events may give rise to post traumatic stress disorder or trigger other common mental health disorders.
- Children who do not have secure attachment to a primary caregiver in early childhood are less able to cope with stressors later in life.
- Drug-induced psychosis (e.g. dagga), alcohol induced encephalopathy and alcohol withdrawal are common in many communities.
13-13 Apart from mental distress, are there other problems caused by mental health disorders?
Yes. There are other very important consequences of mental health disorders for the individual and for others in the family:
- Mental health disorders can contribute to poverty and social isolation when:
- There is social stigma.
- Bread-winners are unable to work to their full ability.
- People with mental health disorders are less likely to be adherent to treatment for other health problems, such as TB treatment.
- Mental health disorders in new mothers are very common and can have lasting effects. The children of mothers with untreated mental health disorders are:
- More likely to be underweight or stunted.
- More likely to be hospitalised with problems such as diarrhoea.
- Less likely to finish their course of immunisation.
Mental health disorders are common, often undertreated and contribute to the cycle of poverty and ill health.
13-14 What are congenital disorders?
These are abnormalities of structure or function present at birth which result in a wide range of chronic problems.
Structural problems include:
- Cleft lip and palate
- Club foot
- Dislocated hip
- Heart, kidney or bowel abnormalities
- Neural tube defects and microcephaly
Functional (metabolic) problems include:
- Cystic fibrosis
As mortality due to infection decreases more childhood deaths are due to congenital disorders.
13-15 What does the “epidemiological transition” mean?
Epidemiology is the study of the distribution of disease and the relationship between risk factors and disease. Poorer countries tend to have a high burden of disease from infections and childhood mortality. As countries become richer, this burden of disease tends to be replaced by chronic non-communicable diseases. This change is called the “epidemiological transition”.
In low and middle-income countries today, there is a rising burden of chronic non-communicable disease while there is still “unfinished business” from the burden of infections and childhood mortality. Therefore the epidemiological transition in low- and middle-income countries has resulted in a “double burden of disease”. South Africans sometimes add maternal and perinatal mortality as well as TB and HIV and describe a “quadruple burden of disease”.
Epidemiological transition means that infections and childhood deaths are replaced by non-communicable diseases as the main causes of death in countries with an increasing standard of living.
13-16 Why are many non-communicable diseases not being prevented?
Great advances have been made in the prevention of infectious diseases over the past 100 years. Health departments are very active in reaching immunisation targets, and epidemics receive national attention. Water quality, sanitation and food safety have improved.
In contrast, little progress has been made in the prevention of chronic non-communicable disease. One of the reasons for this is that many chronic diseases are related to behaviour choices and it is often felt that the chronic disease problems could be solved if only people had the right information and behaved more responsibly. This means that preventative measures for chronic disease tend to be left in the hands of the individual.
Of course, people are ultimately responsible for their own health, but it is important to understand that unhealthy lifestyles are often a result of the environment in which people live. For example, the availability, quality and affordability of foods, family and social norms, advertising, gangsterism and few educational opportunities.
13-17 Can governments do anything about chronic lifestyle diseases?
Yes. Government departments are responsible for the provision and regulation of health services. They can also control people’s exposure to risk factors, including their behaviour choices, using the 3 tools of taxation, legislation and regulation. These are discussed in Part 3: What are the solutions?.
Case study 1
An overweight patient with diabetes has been extensively counselled about the required dietary changes. However, a nurse later sees him in the local supermarket buying chicken wings, a 2 litre cool drink and a large packet of chips for lunch. The following day, the same nurse is on duty in casualty when the patient is admitted with high blood sugar and chest pain.
1. What is the nutritional value of his lunch choice?
The patients needs to lose weight to improve the management of his diabetes but his choice of cool drink, chicken wings and salty chips is not a well-balanced lunch. Chicken wings are high in fat, cool drinks are loaded with sugar, and chips have added salt. These are all foods he should avoid.
2. What other cardiometabolic diseases is this patient at risk of?
The important cardiometabolic diseases are diabetes, hypertension, coronary heart disease and stroke. These are also called chronic diseases of lifestyle. They are usually associated with abdominal obesity, unhealthy diet and too little exercise.
Case study 2
In 2011, the Australian government introduced new legislation that banned cigarette manufacturers from using attractive packaging. Instead, cigarettes could only be sold in plain packets that had graphic photographs of smoking related diseases and warnings about health risks on them. The tobacco giant Philip Morris sued the Australian government. Their argument was that the measure affected their investment and this was a breach of a free trade deal between Pacific Countries. So far, the case has been through the Australian courts and an international court in Hong Kong. The courts have all found in favour of the Australian government. This is a case of a government taking quite radical measures to control the exposure of a population to a risk.
1. Can you think of other risk factors for non-communicable diseases where plain packaging might help?
Plain packaging might reduce the attractiveness of:
- “Junk food” from fast food outlets
- Canned and bottled cool drinks
- Alcoholic drinks