african sleeping sickness disease paper

Rasan Cherala

2/24/2014

Trypanosomiasis: A History, Challenges, and a Search for Cost-Effective Measures

for Eliminating Disease

Rasan CheralaAnthropology 415: Trypanosomiasis Disease Paper

The Human Element: A buzzing sound emanates slowly from a corner of the room. It

drifts towards the man sitting on the floor outside of his hut. His children are running around

outside, and he feels a slight pain from the bite from a tsetse fly. He swats at it, it flies away, and

he gives it little thought. A week later, he feels swelling of his lymph nodes on his neck.

Sickness sets in. He becomes very lethargic and starts to have bouts of fever, headaches, joint

pains, and itching. Eventually, over the course of a few months, he undergoes changes that lead

to confusion, changes in behavior, sensory disturbance, and poor coordination. He and his family

write it off as a sickness that will go away over the course of time and with rest. But

Trypanosomiasis, also known as African sleeping sickness, isn’t a disease that one can fight

alone. Left untreated, it can be fatal1.

Disease and transmission: Trypanosomiasis is caused by the species of tsetse fly known

as Trypanosoma brucei gambiense, which acts as a vector for the protozoan parasite

Trypanosome. This particular species of tsetse fly, hereafter referred to as T.b.g., accounts for the

cause of 98% of reported cases of sleeping sickness2. The T.b.g. flies are found in 24 countries in

west and central Africa. Domestic cattle and endemic animals act as reservoirs for the

trypanosome parasite. Often times, the parasites can remain dormant within the infected

individual for months or weeks after infection, and by the time symptoms of infection present

themselves, the central nervous system’s function has been disrupted.

Disease progression: The actual infection after the bite from T.b.g. takes place in several

stages3. The first stage involves the actual multiplication of the protozoan Trypanosomes in the

subcutaneous layers. In several days (2-3) there is itching and swelling of the area surrounding

the bite along with redness. After about 6 days, a boil-like formation happens at the site of the

bite and is referred to as a trypanosomal chancre4. Upon multiplication, the immune system’s

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response is to have a fever to rid the body of the parasites. Thus, the blood stage is characterized

by fever, headaches and joint pains. Typically 5-12 days after infection, Trypanosomes are found

in the blood. The enlarged lymph nodes are a sign of infection by the T.b.g. fly and is referred to

as Winterbottom’s sign. As a result of the release of toxic materials by the parasites, the body

responds by undergoing cyclic fevers every 7 to 10 days5. In the later stages of the disease, the

crossing of the Trypanosomes into the blood-brain barrier leads to personality changes,

insomnia, irritability, and inflammation as a result of compromise of the Central Nervous

System. Sometimes this process can take years, and the disease progresses with increasing

severity over the course of time. Demyelinating meningoencephalitis (swelling of the brain’s

outer covering) as a result of inflammation can lead to cerebral edema, hemorrhages, pericarditis,

and anemia. Final stages of the disease lead to apathy, coma, somnolescence and death caused by

secondary infections6. African sleeping sickness is treatable, however, and outcomes can be

greatly improved granted the right treatment is available.

Available treatments: Treatment is possible in many forms, but only after detection of

the Trypanosomes. This is possible through serological analysis, which can be a large investment

of resources due to the long incubation periods of the first phase of the disease7. Treatment

depends largely on the phase of the disease. Drugs used during the first phase are typically less

toxic and are easier to administer compared to drugs used during the second stage8. Drugs used

during the second stage need to be able to cross the blood-brain barrier, and also result in more

complications8. First stage treatment includes the use of Pentamidine and Suramin. Drugs

administered during the second stage include Melarsoprol, Eflornithine, and a combination of

Nifurtimox and Eflornithine9.

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History of disease: African Trypanosomiasis has been present for thousands of years in

Africa, and has had an effect on the selection and survival of hominids. The transmission of

Trypanosomiasis is directly related to the range of the tsetse fly, and ranges between 14 degrees

North and 20 degrees South latitudes. Animal strains of the disease cause weakening of animals

through emaciation, hair loss, eye discharge, edema, and paralysis10. Consequently use of

domesticated and farm animals can be complicated and rife with problems in these regions. The

two subspecies that give rise to human Trypanosomiasis include T. brucei gambiense and T.

brucei rhodesiense. A third species known as T. brucei brucei can only infect animals. Animals

endemic to Africa exhibit resistance to Trypanosomiasis as a result of the long coexistence with

trypanosomes transmitted by the tsetse fly over the last 35 million years. Domestic breeds not

endemic to the region do not display such resistance. Additional data suggests that early

hominids were selected for according to trypanosome resistance11. The fact that humans are

resistant to all other species of Trypanosomiasis that are carried by other types of flies shows that

African sleeping sickness developed relatively recently in human history. T.b.rhodesiense is not

as infective because of the spread of a Serum Resistance gene (SRA) throughout human

populations in the area via genetic transmission.

In more recent history, there have been very severe epidemics throughout the 1900’s. The

first one lasted in Uganda from 1896 to 1906 and approximately 300,000 and 500,000 people

were estimated to have died in the Congo Basin and Kenya and Uganda respectively. After this

epidemic, the focus turned to finding cures for the disease. In 1926, French military surgeon

Eugene Jamot set up a mobile team which helped reduce the prevalence of sleeping sickness in

Cameroon from 60% to .2-4.1% within 11 years. Mobile teams systematically detected and

treated disease and eliminated parasite reservoirs.12 Additionally, African Trypanosomiasis was

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controlled using vector control, host reservoir control, and game destruction. By the beginning of

the 1960s, advances in second stage drugs led to significant reductions in Trypanosomiasis rates.

Post-1960 however, independence combined with large debts and armed conflict led to political

instability. Economic ruin led to the compromise of basic health facilities and famine and poor

living conditions primed countries such as Angola, Congo, Southern Sudan and Uganda for

resurgence of Trypanosomiasis. The current epidemic has lasted from 1970s and has steadily

gotten more severe over the course of time.

Specific Programs-Lambwe Valley: In the Lambwe valley in Kenya, an initiative was

taken up by the International Center of Insect Physiology and Ecology to implement a low-cost

method of reducing tsetse fly, and consequently Trypanosomiasis rates 13. The Kibwer and

Samba communities of that region used their own resources to follow the methodologies outlined

by the ICIPE. In the program, farmers were trained by ICIPE experts and then disseminated to

other communities to teach them about the use of a trap known as a NGU trap. The communities

were taught the basic science of Trypanosomiasis transmission and this knowledge enabled them

to understand the underlying causes for sleeping sickness. Communities, upon learning this

information collectively raised $3000, and deployed 270 traps in 2530 working days14. NGUs are

efficient odor-baited tsetse traps that result in 90.99% reductions of tsetse populations. Upon

learning about these traps, initially community members were skeptical but after eight months,

the reduced number of tsetse flies in the traps proved that they were indeed effective and

communities actually approached ICIPE about organizing their own meetings and raising more

funds for further work.

In this program, self-reliance and community based organization were considered a key

part of the success. Previous efforts to eradicate tsetse flies had been on geographically large

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scales and often used expensive methods. Most of those methods are beyond the capabilities of

poor countries that have tsetse fly problems. Additionally, methods such as spraying pesticides

either aerially or on the ground have caused major environmental damages. Finally, efforts are

often headed by outside agencies and community members were not seen as the target users,

which impacted the sustainability of such projects. The ICIPE program however used a cheap,

proven method, that when used was successful. In the beginning of the 1990s in the Lambwe

valley, Trypanosomiasis had the potential of affecting 50000 people in an area of 450 square

kilometers15.

By making community members stakeholders in the process, the ICIPE program created

a sense of personal responsibility to help out in the efforts. Additionally, by having farmers teach

other community members, the information was taken and actually used because of the personal

connection that people had. The original group of 42 farmers conducted meetings and a five-tier

decentralized organizational system. The total scope was two sub locations known as Kibwer and

Samba, and these regions contained 44 villages and 1800 homesteads. The system of

organization was a democratic one where leaders were elected from within communities. In

order for the tsetse fly to be successfully trapped, five key events and skills were necessary.

Those included management, funds, materials, labor and premises for storing materials and

holding meetings. Each consecutive year of the program led to an increase in the number of traps

being deployed in the region. Most of the working hours were spent servicing traps. Thus, this

program helped identify whether or not NGUs were a good model, and how a community driven

sustainable model could be applied to other regions. The study looked to analyze the impact of

the traps environmentally as well as socially. The cultivation of land increased from 4% of the

total land cover in 1977 to 37% or more in 1993, although only 20% is due to tsetse control.

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Additionally, the mindset of farmers towards native species that acted as hosts changed after this

program16. Initial ideas included killing off the wildlife to prevent human infection. However,

knowledge that the traps actually afforded the wildlife protection from Trypanosomiasis as well

actually encouraged conservation efforts. In spite of the fact that this program was only four

years long (1992-1996), it provided a model for future work in Kenya17.

The 1992 ICIPE model was used as the basis for many programs in Kenya. More recent

programs that have focused on Trypanosomiasis have used similar low cost approaches. Since

1992, there has apparently been no record of people dying in this region because of efforts such

as this. This approach used in the ICIPE program takes some aspects of how the work was

conducted from previous work done in public health. The use of community organized programs

that targeted rural areas with little access to resources shows this. Great gains were achieved

because the people from these communities were present in the process. Although no structural

changes were made through building of clinics in these areas to meet the needs for access to

medical care, the use of NGU traps reduced prevalence of Trypanosomiasis, thereby reducing the

burden of disease.

One of the complications in dealing with the tsetse fly is that they exist in great numbers

over a vast area. Though Kenya may be declared “sleeping sickness free”, the fact that

neighboring countries have large populations of flies means there is possibility of resurgence of

the disease unless constant monitoring is taking place. Strategies to address this should include

continued servicing and implementation of low-cost, effective measures such as NGUs in areas

close to regions known to have ideal breeding grounds for the flies.

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Role of anthropologists in treating Sleeping Sickness: Anthropologists have been

present throughout the course of sleeping sickness campaigns. They have been important in

identifying local beliefs, and how those beliefs affect patterns of resort. A study conducted by the

Institute of Anthropology of the University of Nairobi in 2011 investigated access barriers to

health care in Teso district in Western Kenya. The focus in this case was on sleeping sickness,

and over 400 people were interviewed. The study found that the largest issue was stigma against

the National Sleeping Sickness Referral Hospital (NSSRH) based at Alupe. The study found that,

“barriers include social stigma associated with the NSSRH, the disease and the treatment

process; lack of knowledge about the epidemiology of sleeping sickness, the location and

functions of NSSRH among community members; ethnicity; and the existence of a multiplicity

of healthcare options, both formal and informal, within the research site.18” Additional issues in

access to care included access issues to actual care because of long queues, waiting times, and

harassment by health care workers of healthcare seekers due to perceived differences. This study

suggested that clinics be built with locally trained health workers in each village or district to

deal with the volume of patients and to cut down on wait times. Additionally, it suggested

sensitization and training of healthcare workers at the NSSRH to improve relations with

healthcare seekers.

Other roles of anthropologists: Anthropologists can continue to provide insight into

how local practices, beliefs, and customs affect access to care. In the ICIPE program, 40% of

workers were women and the gender makeup of the workforce may have affected success rates19.

Perhaps an anthropological strategy investigating the gender relations of certain areas could give

insight into how programs can be organized differently to increase women’s roles in such

programs. Additionally, anthropologists can provide information about how effective treatment

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really is by conducting interviews of healthcare seekers. Identifying pitfalls in the system can

help increase access to care and also reduce mortality rates due to Trypanosomiasis.

Other Recommendations for Control: Past strategies in dealing with Trypanosomiasis

have included removing human populations from areas susceptible to disease, using

chemoprophylaxis on human populations, and eliminating T.b.g. from animal reservoirs.

Insecticide treatments, though effective in reducing tsetse fly populations also has adverse

environmental impacts and in the long term could adversely affect human populations in addition

to wildlife. As cattle are such a large part of livelihoods and agriculture in the tsetse belt,

targeting cattle as a point of intervention is important. By using prophylactic treatments such as

deltamethrin, disease burdens can be reduced by as much as 70-100%20. This insecticide, when

applied to the bellies and legs of cattle, can contribute to decreases in bovine Trypanosomiasis of

up to 40-98%21.

Challenges: One large challenge faced in controlling Trypanosomiasis is the fact that it

is a zoonotic disease. The form of the parasite that infects humans can survive in domestic

animals such as cattle and also in wild animals. Thus, families or individuals living with

livestock are at a greater chance of being infected because their animals can act as reservoirs for

the parasites. This is one of the reasons why the disease has persisted even after historical

attempts to cut down on transmission rates. Consequently, rural populations are more likely to be

affected by Trypanosomiasis because of the scarcity of human and monetary resources that

prevent separation from animals and screening for the parasites. Additionally, many patients lack

access to basic health facilities and often have to travel great distances to receive treatment. The

ideal warm and humid environment provided for tsetse flies in many of these African countries

also makes it difficult to contain the tsetse fly population. In addition to the conventional form

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of infection via a T.b.g. bite, transmission of Trypanosomiasis can happen in a few other ways.

Mother to child transmission can occur when the parasites cross the placenta and infect the fetus.

Other blood-sucking insects can also transmit the Trypanosomes, however it is unknown to what

extent this is the case. Other forms of transmission can occur via use of contaminated needles for

vaccinations and immunizations22.

Final thoughts: Trypanosomiasis is a deadly disease that continues to affect many

people throughout the world. The management of the disease is complicated by societal

conditions and economic conditions caused by war and famine. Agricultural and rural regions

continue to be areas most likely to be affected by the disease due to hospitable environments and

prime breeding grounds for the tsetse fly T.b.g.. Low-cost, community based programs can

improve the health of residents through vector control. Although access to basic medical care

facilities remains an issue, perhaps by mitigating life threatening diseases such as

Trypanosomiasis, it is possible to alleviate some of the pain and suffering of people in these

areas.

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Notes:

1. Brun, 2014.2. WHO, 2013.3. Ibid., 2013.4. UCLA, 2010.5. Ibid., 2010.6. Ibid., 20107. WHO, 2013. 8. Kotlyar, 2014.9. Steverding, 2014.10. Ibid., 2014. 11. Ibid., 2014.12. Ibid., 2014. 13. Ssenyonga, 1994.14. Ibid., 1994.15. ICIPE, 1994.16. Ibid., 1994.17. ICIPE, Kenya.18. Wanjala, 2014.19. ICIPE, 1994.20. Kotlyar, 2014.21. Ibid., 2014.22. CDC, 2012.

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http://www.cdc.gov/parasites/sleepingsickness/


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african sleeping sickness disease paper

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