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Neglected Diseases

Neglected Diseases

 Flytrapstsetse a tsetse fly

Tsetse flies are attracted to blue.
These traps on display, show how they attract flies in the wild.                                             

Neglected Diseases

Neglected Diseases are diseases that are considered neglected when treatments either don’t exist in that situation or when they are inadequate. Neglected diseases mainly effect people in developing countries as in many countries of Africa or Asia. The term ‘most neglected’ is used to mean diseases that occur among the world’s poor, thus for them are unattainable.  Some ND’s and NTD( neglected tropical diseases)  are Tuberculosis, HIV/AIDS, Malaria, Schistomiasis, Leprosy, Guinea Worm, Elephantiasis, Chagas Disease, Buruli Ulcer, Leishmaniasis, and Trypanosomiasis (Sleeping Sickness) which in the last ten years has seen a heightened chance of being eliminated.

Elimination of a disease is referred to as a progressive drop to a manageable percentage of people being effected due to control measures. Eradication of a disease is the extinction of the disease, something that does not happen frequently due to the constant risk of imposing conditions.

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Excerpt on the question, “Why are neglected diseases still neglected? “

From a presentation to James Madison University’s Pre-Med Class on Neglected Diseases

    By Kay Kobbe,President of KFWH

 ”Why are neglected diseases still neglected?”

 My resources come directly from our  Advisors, Dr. Jean Jannin, Coordinator of Neglected Diseases at the World Health Organization; Dr. Peter Hotez, Professor  and Department Chair of Microbiology and Tropical Diseases at George Washington University and  Director of the Sabin Vaccine Institute in Washington, DC; and Dr. Christian Burri, Director of Vector Control at the Swiss Tropical Institute in Basel.

 What are  neglected diseases? Diseases are considered neglected when treatments either don’t exist in that situation, or they are inadequate. ND’s mainly effect people in developing countries, most often in Africa and Asia. The term “most neglected” is used to mean diseases that occur  among people who are so poor that there is no hope for purchasing treatments. Millions of people die each year of preventable and treatable diseases. Communicable diseases such as AIDS, TB, and malaria killed 14 million people in 1999 and 97% of these occurred in developing countries. Besides high costs, too little money is going into health research for the needs of the world’s poorest people. Only 10% of global health research is devoted to 90% of the world’s total health burden.

 Most research-based drug companies do not invest money in programs which are not going to earn profits for their shareholders. Tropical diseases are good examples of neglected diseases. Only a small percentage ( approx. 10%) of drugs approved are specifically developed for tropical diseases.

 According to WHO, the list of neglected diseases comprises in order of decreasing prevalence: roundworm, whipworm, hookworm, snail fever (shistosomiasis), elephantiasis, trachoma, leishmaniasis, Chagas Disease, leprosy, African Sleeping Sickness (Trypanosomiasis), guinea worm, and buruli ulcer.  WHO estimates that 1 billion people- that would be 1/6th of the world’s population,  suffer from these diseases.

 So why are these diseases yet neglected?

 According to Dr. Burri, the following affects the percentages that are yet neglected:

 

  • Most patients live in rural  areas and are not of interest for political support and intervention.
  • The countries most affected have a very limited research culture and “know-how”, which hampers local approaches.
  • Each of the diseases has a low prevalence, even if they have a huge impact; so the development of medicines is not economically interesting to commercial companies.
  • A career in the field may not be as attractive for many researchers, as merits can be better gained in highly observed research fields.

Dr. Schofield states there is one problem with the “numbers game” of deaths for hugely prevalent diseases like AIDS, malaria, and TB:  these diseases become completely unimportant if you happen to have trypanosomiasis!  Chagas Disease, he says, is a disease where they see the punishment for success as numbers drop after a control programme is successful. Dr. Schofield tends to focus instead, on “what is doable today”- hence his interest in controling the trypanosome in Africa and in Latin America. He feels there is no real technical problem for these, it is just a question of ‘getting on with the job.’, “although that can be difficult a times, presenting quite a series of operational and political challenges.”

 There are now new incentives for companies to develop and invest in new drugs and vaccines against tropical diseases, which cut down the trial time restrictions, often appealing to major companies.

 In a recent paper for the NTD Strategic and Technology Team and Advisory Group, Dr. Jannin and his team, including Dr Christopher Schofield, write about the concept of ‘sustainability of elimination’ for NTD’s.

 In this draft, it is stated that the success of any public health initiative depends strongly on the level of societal and political commitment. Elimination and eradication were defined as the ultimate goals of Public Health, evolving from vector and disease control. Elimination is not an ultimate goal- it is part of a process where continued intervention measures are needed to prevent re-establishment of transmission or high levels of prevalence. Elimination refers to the “status of the disease, when it is no longer considered a major health problem.” It is not looking at an end point of zero cases, as in eradication; but a “status which must be sustained thanks to the implementation of new innovative interventions.” There is, as Dr. Jannin and Dr. Schofield point out, a “punishment for success” when elimination is determined. This shows itself in the following ways:

 

  • Governments are assessing priorities in light of the immediate burden, and will ultimately withdraw resources.
  • NGO’s leave and move to other more critical areas.
  • National programmes are dismantled due to the reduction of cases.
  • No replacement is made for trained human resources.
  • No incentive is provided to encourage research and development.
  •  There is a trend for scientists and MD’s to go towards new fashioned disciplines, leading to a lack of trained professionals in NTD areas.

 

To support this theory, various diseases were considered eliminated around the 1960’s and then reappeared due to the above. They included: HAT, yaws, kala azar in India,malaria in Venezuela, to name a few.

 This innovative and much- needed vision may be a task for some of you to tackle in the near future, continuing the process toward sustaining elimination, as proves to be necessary.

 

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KFWH Targeted Diseases       

BURULI ULCER:

Buruli Ulcer is caused by a bacterium found in contaminated water.  It is not known exactly how infection occurs. The disease is prevalent in areas of Africa and Australia where there are polluted lakes and streams.

  • Symptoms: The disease often appears initially as a small, red bump on the skin. In later stages, it is characterized by large areas of missing skin, that  appear as large, open wounds. Despite its gruesome appearance, the disease is painless because it destroys the nerves in the infected areas.
  • Diagnosis and Treatment: If caught in the early, initial stage, the treatment is a simple surgical procedure that is very effective. In later stages it requires long, extensive surgeries that could run to $10,000. Antibiotics have been used with mixed results. The condition was improved, but no eradicated. The victims are often left crippled or disfigured.  Early diagnostics and more refined antibiotic  treatments  are now being developed.
  • Prevention: A vaccine, if one could be developed, might be the most effective way to prevent the disease over the long term. Education for early detection could minimize the effect of the disease.  Also the teaching of self-care techniques could minimize disability.  These would include wound care and joint flexibility exercises.

 

CHAGAS

  • Chagas is a parasitic disease transmitted by insects. It is most prevalent in Latin  America. The beetles that transmit Chagas live in cracks in the walls of mud and straw housing, which are common in rural areas and urban slums.  It affects an estimated 16-18 million people and claims 50,000 lives annually.
  • Symptoms:  There are often no apparent symptoms after infection, with the exception of a  short- lived flu-like reaction. The disease is progressive and after 10 to 20 years, thirty percent of those infected will develop permanent and often irreversible damage to the heart, esophagus, and colon.
  • Diagnosis and Treatment:  Diagnosis is difficult because of lack of symptoms and often requires several blood tests to confirm the presence of the disease.  Two drugs are available, but are expensive. Treatment for a child under 15 is around $40. The drugs are not as effective, though, when the disease reaches its chronic,often fatal, state because of cardiac and digestive complications. Research is on-going for both diagnosis and treatment.
  • Prevention:  Treating homes with insecticide will kill the beetles that carry the disease. Eliminating the insects can cut new infections to zero.  Prevention is especially important because even after being treated for one infection, reinfection can  occur if the homes are still infested. Education and field support are necessary to take these steps.

 

LEISHMANIASIS

Leishmaniasisis carried by a parasite transmitted by the bite of a sandfly. The disease occurs in three forms, one of which is Visceral Leishmaniasis (also called Kala-Azar) that can be fatal. The milder forms lead to scars and disfigurement. The disease affects 12 million people in India, Bangladesh, the Sudan, Brazil, Bolivia, and Peru.

  • Symptoms: The milder forms of the disease produce skin ulcers or sores that can lead to destruction of the mucous membranes of the nose, mouth, and throat. Visceral Leishmaniasis (Kala-Azar) is characterized by  fever, weight loss , swelling of the liver and spleen and is usually fatal if untreated.
  • Diagnosis and Treatment: All forms of Leishmaniasis can be treated when drugs are given in the early stages. The current cost is about $300 for one patient.  Prevention is effective through use of simple procedures, but even these are often not possible in poor, rural areas.  A new, affordable cure for Visceral Leishmaniasis  has been recently developed by One World Health and a delivery method for the treatment is being organized.
  • Prevention:  The best way to prevent Leishmaniasis is for people to take steps to minimize their risk of being bitten by the sandfly.  This would include wearing long pants and long sleeve shirts, using insect repellent and sleeping under a bed net.  However, because the disease is most common in hot climates, these measures tend to be uncomfortable .

 

SLEEPING SICKNESS OR TRYPANOSOMIASIS- our number 1 target since 2001

Sleeping Sickness became KFWH’s first targeted disease in 2001 when one of our founders witnessed a CBS 60 Minutes film on the plight of its victims in Africa. Dr. Micheleen Richer was shown to be working in the Sudan to fight against this fatal situation and  making a huge difference when funds simply ran out.  Dr. Richer is currently working in Sudan, and is now on our Advisory Board.

Definition of the disease:

Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a vector-borne parasitic disease. The parasites concerned are protozoa belonging to the Trypanosoma Genus. They are transmitted to humans by  tsetse fly (Glossina Genus) bites which have acquired their infection from human beings or animals harboring the human pathogenic parasites.

Tsetse flies are found only in Africa. Only certain species are incriminated in the transmission of the disease. Different species have different habitats. They are mainly found in vegetation by rivers and lakes, gallery-forests and vast stretches of wooded savannah.

Another form of trypanosomiasis occurs in South America. It is known as American Trypanosomiasis or Chagas disease. The causal organism however is a different species from those causing HAT.

  • Sleeping sickness occurs only in sub-Saharan Africa, in regions where there are tsetse flies that can transmit the disease. For unexplained reasons as yet, there are many regions where tsetse flies are found, but sleeping sickness is not.
  • The rural populations living in regions where transmission occurs and which depend on agriculture, fishing, animal husbandry or hunting are the most exposed to the bite of the tsetse fly and therefore to the disease.
  • Sleeping sickness generally occurs in remote rural areas where health systems are least effective, or non-existent. The disease has a tendency to spread with socio-economic problems. Displacement of populations, war and poverty are important factors leading to increased transmission.
  • The disease develops in foci whose size can range from a village to an entire region. Within a given focus, the intensity of the disease can vary from one village to the next.

Human African Trypanosomiasis takes two forms, depending on the parasite involved:

  • Trypanosoma brucei gambiense (T.b.g.) is found in west and central Africa. This form represents more than 90% of HAT reported cases and causes a chronic infection and a person can be infected for months or even years without major signs or symptoms of the disease. When symptoms do emerge, the patient is often already in an advanced stage when the central nervous system is involved.
  • Trypanosoma brucei rhodesiense (T.b.r.) is found in eastern and southern Africa. This form represents less than 10% of HAT reported cases and causes an acute infection. First signs and symptoms can generally be observed after only a few months or weeks. Although the disease develops more rapidly it also ends in a central nervous system involvement.

Animal trypanosomiasis

Other parasite species and sub-species of the Trypanosoma Genus are pathogenic to animals and cause animal Trypanosomiasis in many wild and domestic animal species (in cattle the disease is called Nagana, a Zulu word meaning “to be depressed”). Animals can be hosts to human pathogen parasites, especially T.b. rhodesiense; thus domestic and wild animals are an important parasite reservoir. Animals can also be infected with T.b. gambiense, however the precise epidemiological role of this reservoir is not well known. The disease in domestic animals and particularly cattle is a major obstacle to the economic development of the rural areas affected. Past major epidemics of sleeping sickness have caused many human losses and the abandonment of fertile land.

Major Epidemics:

There have been several severe epidemics in Africa over the last century: one between 1896 and 1906, mostly in Uganda and the Congo Basin, one in 1920 in several African countries, and the last one began in 1970. The 1920 epidemic was arrested due to mobile teams systematically screening millions of people at risk, by the mid 1960s the disease had practically disappeared. After that success, effective surveillance was relaxed, and the disease has reappeared in several foci over the last thirty years. Recent WHO efforts and those of national control programmes have inverted the upward trend of new cases.

Sleeping sickness threatens millions of people in 36 countries of sub-Saharan Africa, while a mere fraction of them are under surveillance with regular examination, have access to a health centres that can provide diagnostic facilities or are protected by vector control operations.

Exhaustive screening of the population exposed to the bite of infected flies calls for important human and material resources. Because in Africa such resources are often lacking, particularly in remote areas where the disease is mostly found, many infected individuals may die before they can ever be diagnosed and treated.

  • In 1986, a panel of experts convened by WHO estimated that some 70 million people lived in areas where disease transmission could take place.
  • In 1998, almost 40 000 cases were reported, but it was considered that this number did not reflect the true situation and it was estimated that between 300 000 and 500 000 more cases remained undiagnosed and treated.
  • During epidemic periods certain villages of the Democratic Republic of Congo, Angola and Southern Sudan, the prevalence has reached over 50%. Sleeping sickness was then the first or second greatest cause of mortality, ahead of HIV/AIDS, in those communities.
  • In 2000, the World Health Organization established a public-private partnership with Aventis which has allowed establishing a surveillance team, providing support to endemic countries in their control operations and supplying drugs free of charge for the treatment of patients.
  • By 2005 surveillance has been reinforced and the number of new cases diagnosed throughout the continent was substantially reduced; between 2001 and 2004 the figures for both form of the disease together were respectively 27240, 24230, 20387 and 17420.
  • In 2006, the registered successes in curbing the evolution of sleeping sickness has motivated a number of private parties to sustain the initial effort to eliminate the disease as public health problem.

Countries are placed in various categories in terms of prevalence however the spatial distribution of the disease in each country is very diverse; it is found in foci of variable sizes. In 2005 major flare-ups have been observed in Angola, the Democratic Republic of Congo and Sudan. Some countries like Senegal, The Gambia, Guinea Bissau, Ethiopia, Namibia, Swaziland and Botswana transmission seems to have been interrupted and no new cases have been reported in several decades. It is difficult to assess the situation today in a number of past endemic countries by lack of surveillance and diagnostic expertise.

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Infection and Symptoms:

The disease is transmitted through the bite of an infected tsetse fly. At first the trypanosomes multiply in subcutaneous tissues, blood and lymph, in time it will cross the blood-brain barrier to invest the central nervous system. The process can last for years with T.b. gambiense.

  • Mother-to-child infection: the trypanosome can cross the placenta and infect the fetus.
  • Mechanical transmission is possible. However, it is difficult to assess the epidemiological impact of transmission through other blood sucking insects.
  • Accidental infections have occurred in laboratories by pricks with contaminated needles.

The early stage of the disease entails bouts of fever, headaches, joint pains and itching (pruritus). The second stage, known as the neurological phase, begins when the parasite crosses the blood-brain barrier and invades the central nervous system. In general this is when the signs and symptoms of the disease appear: confusion, sensory disturbances and poor coordination. Disturbance of the sleep cycle, which gives the disease its name, is an important feature of the second stage of the disease. Without treatment, sleeping sickness is fatal.

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Disease Management:

Disease management is performed in three steps:

  • Screening is the initial sorting of people who might be infected. This involves the use of serological tests and /or the checking for clinical signs generally swollen cervical glands.
  • Diagnosis shows whether the parasite is present.
  • Phase diagnosis shows the state of progression of the disease. It entails examination of cerebro-spinal fluid obtained by lumbar puncture and is used to determine the course of treatment.

Diagnosis must be made as early as possible prior to central nervous system involvement in order to avoid the complicated, difficult and risky treatment procedure of the second stage.

The long, asymptomatic first stage of T.b. gambiense sleeping sickness is one of the factors that imposes exhaustive active screening of the population at risk to identify patients at an early stage and prevent transmission.

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Treatment:

The type of treatment depends on the stage of the disease. The drugs used in the first stage of the disease are less toxic, easier to administer and provide a better chance of cure, this is why the infection must be diagnosed as early as possible. Treatment success in the second stage depends on having a drug that can cross the blood-brain barrier to reach the parasite. Such drugs are more complicated to administer. Four drugs are registered for the treatment of sleeping sickness and provided free of charge to endemic countries through a WHO private partnership with sanofi-aventis (pentamidine, melarsoprol and eflornithine) and Bayer AG (suramine).

First stage treatments:

  • Pentamidine: discovered in 1941, it is used in treatment of the first stage of T.b. gambiense sleeping sickness. In spite of a few undesirable effects, it is well tolerated by patients.
  • Suramine: discovered in 1921, it is used in treatment of the first stage of T.b. rhodesiense. There are certain undesirable effects, especially on the urinary tract and allergic reactions.

Second stage treatments:

        Melarsoprol: discovered in 1949, the drug is used in both form of infection. It is an arsenical derivative and has many undesired side effects. The most dramatic being a reactive encephalopathy (encephalopathic syndrome) which can be fatal (3% to 10%). In the last few years resistance to the drug has been observed in several foci particularly in central Africa.

        Eflornithine: this molecule was registered in 1990. It is only effective against T.b. gambiense. It is an alternative to melarsoprol treatment. The regimen is strict and difficult to apply.

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The Role of the World Health Organization:

Faced with the resurgence of sleeping sickness since the 70s, WHO has over time reinforced its Human African Trypanosomiasis programme to coordinates activities in endemic countries and mobilize a wide range of partners for this purpose.

The WHO Programme provides support and technical assistance to national control programmes. A network has been established comprising donor countries, private foundations, nongovernmental organizations (NGOs), regional institutions, research centres and universities to participate in surveillance and control, and execute research projects for the development of new drugs and diagnostic tools.

The specific objectives of the WHO HAT Programme are:

  • Enhance and animate the networking process
  • Coordinate the sleeping sickness control measures and ensure that field activities are sustainable;
  • Strengthen existing surveillance systems;
  • Support monitoring of treatment and drug resistance through the network;
  • Promote inter-agency collaboration with the FAO and the IAEA;
  • Develop an information system and implement training activities.

 Our founding mentor, Dr. Jean Jannin and his department of Tropical Neglected Diseases at the World Health Organization, Geneva, including Dr. Pere Simarro, Department Chair of Sleeping Sickness have made giant steps toward elimination of the disease giving Hope for the people of Africa. Dr. Jannin andDr. Simarro serve on the KFWH Advisory Team and Advisory Board.

The Staff at WHO is willing to help further our education by answering questions from students related to any of our targeted diseases. Please submit questions via our Message Board Forum.

 

 More information and recent development concerning HAT surveillance and control are available on the WHO HAT website at http://www.who.int/trypanosomiasis_african  under Human African Trypanosomiasis Surveillance and Control Programme.

 Information compiled from publications and personnel of the World Health Organization and Doctors Without Borders. Specific sources available upon request.

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 KFWH Targeted Diseases/Other Descriptions

Sleeping Sickness

Trypanosomiaisis or Sleeping Sickness was our first target disease. Treatment has come along way since pharmaceutical companies are now donating drugs for the Human Trypanosomiasis form. Sleeping Sickness is a parasitic disease carried by the tsetse fly, mostly in sub-Saharan Africa. People infected become carriers themselves of the disease infecting other fly bite victims.

Chagas

Chagas Disease is a parasitic disease transmitted by a beetle that lives in cracks in the walls of mud and straw housing. It affects approximately 16-18 million people a year , and claims 50,000 lives annually, mostly in Latin America. Nine cases of Chagas were surprisingly found in the United States last year, causing the Center for Disease Control in Atlanta to focus a department on the disease.

Buruli Ulcer

After much discussion and research, we decided to target diseases that are not being funded and fully recognized in our western world.  Buruli Ulcer is one such disease. This disease is caused by a bacterium found in contaminated water. It is found in Africa and Australia where there are polluted lakes and streams.

Leishmaniasis

Leishmaniasis is carried by a parasite transmitted by the bite of a sandfly. There are 3 forms of the disease. Kala Azar is the most severe and can be fatal. It affects 12 million people in India, Bangladesh, the Sudan, Brazil, Bolivia, and Peru.

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