Why is Lymphatic Filariasis, the most common debilitating mosquito-borne
disease, neglected while Malaria is the targeted mosquito-borne disease?
Zachary Alexander Dowd
Senior Project Advisor: Colleen
Dunning
12th Grade Humanities
Animas High School
22 April 2013
Part 1: Introduction:
Figure 1: Map of Endemic Regions
Lymphatic Filariasis (LF)
is the leading cause of disability on the planet, but most people are unaware
of its existence. Lymphatic Filariasis impacts many people in the endemic
regions (areas affected by the disease) of the world which include South-East
Asia, Africa and other tropical regions (Figure
1). People need to know about this disease so that we can stop it before it
spreads farther. As shown in Figure 1, multiple cases of Lymphatic Filariasis
have been reported in Brazil. Mosquito-borne diseases are a serious issue and Lymphatic
Filariasis is a prime example. While Malaria causes more deaths through the
infection itself, the negative psychological effects caused by Lymphatic
Filariasis lead to suicide, but people are informed about the deaths associated
with Malaria, not the psychological effects of LF.
Part 2: Historical Context
Lymphatic Filariasis is the second most common mosquito-borne
disease and the leading cause of physical disability on the planet. 1.34
billion people are at risk in the main endemic regions (65% within South-East
Asia, 30% in the African region, and the remaining in other tropical regions)
and 120 million people are currently affected by LF (Upadhyayula).
The three different types of filarial parasites that live in
mosquitoes include the Brugia malayi, Brugia timori, and the Wucheria bancrofti.
The Wucheria bancrofti parasite commonly causes Lymphatic Filariasis more than
others. The Wucheria bancrofti is
transmitted into the bloodstream of a human through a mosquito that is
currently infected with filarial larvae. While in a human’s bloodstream, an
adult parasite disperses more larvae throughout the bloodstream, and that is
the point where the infection progresses even farther as the massive amounts of
parasites affect certain parts of the body, by grouping together in an area and
blocking lymph vessels. Repeated mosquito bites during several months are
needed to develop Lymphatic Filariasis. Some people can develop lymphedema,
which is a lymph vessel blockage that causes swelling in the legs, as well as
the arms, genitalia, and breasts. Over time, the disease causes thickening and
hardening of the skin, a condition called elephantiasis which can be fatal.
Filarial infection might also cause pulmonary tropical eosinophilia which can
cause coughing, shortness of breath, and wheezing (Lymphatic Filariasis).
The life cycle of the Wucheria bancrofti is a simple, and
standard parasitic life cycle. It starts with the mosquito containing the
filarial larvae. When the mosquito feasts on a human’s blood, the larvae is
introduced onto the skin of the human host, where they penetrate into the bite
wound. Adults produce microfilariae, which are sheathed and have nocturnal
periodicity (will only appear at night). The microfilariae migrate into lymph
and blood channels through blood and lymph fluid. Then, another mosquito
ingests the microfilariae. While in the mosquito, the microfilariae lose their
sheaths and works their way to the thoracic muscles. While in the thoracic
muscles, the microfilariae develop into first-stage larvae, and eventually,
into third-stage infective larvae. Then, the infective larvae migrate to the
mosquito’s proboscis and can infect another human when the mosquito takes a
blood meal (Wucheria Bancrofti).
Part 3: Summary of Past Research
Few LF supporting organizations exist, but those few organizations
currently have specialists in the endemic regions that are treating people who are
infected with the disease and assist with the disease on a daily basis. This
disease has become classified as a neglected tropical disease because of the
low death rate associated with the disease. Even though mortality associated
with this disease is uncommon, there are so many psychological impacts that
come with the disability caused by the disease (Upadhyayula).
There are many tools that can be used for measuring
disability. One of the tool is the ICF (International Classification of
Functioning, Disability and Health) which classifies two domains, health and
health-related domains. The domains are classified by body, individual and
societal perspectives by means of two lists: a list of bodily function and
structure, and a list of domains of activity and participation. Another tool is
the WHODAS (World Health Organization Disability Assessment Schedule) which has
the same function as the ICF except for the fact that the WHODAS is created and
constantly updated by the World Health Organization (Zeldenryk). The purposes of all of these tools are similar if not
the same. They measure the disability involved with diseases around the world
and they were made for doctors and organizations around the planet to help
diagnose the severity of disability involved with certain diseases. The
resources to help treat this disease exist, but support for this disease is
minimal.
Diseases take a long time to treat (or to create treatments),
but finding a treatment for a barely known disease created even more
complications. Eventually, diagnosis and treatment of this disease became
possible and known. Diagnosis usually involves taking a blood sample and
analyzing it microscopically. The sample has to be taken during the night to
ensure the parasites are in the bloodstream (Lymphatic
Filariasis). The first documentation of this disease was in the 16th
century, when Jan Huyghen van Linschoten wrote about the disease during the
exploration of Goa, but the first successful attempt to treat the disease was
diethylcarbamazine, a worm killing medical composition. Treatment was usually
done using diethylcarbamazine (DEC), but due to the severity of the side
effects ,which include: Conjuctivitis (inflammation of the outermost layer of
the human eye), visual field loss, Encephalitis (acute inflammation of the
brain), retinal hemorrhage, Mazotti Reaction (fever, swollen and tender lymph
nodes, hypotension, abdominal pain), uveitis (inflammation of the middle,
pigmented vascular structures of the eye), nausea, vomiting, and drowsiness;
the medication was discontinued from mass administration (Diethylcarbamazine). Another treatment
for LF is a drug called Ivermectin (Mectizan®) which is commonly used to treat
threadworms, but when combined with a medication called Albendazole, it makes
the perfect combination to treat Lymphatic Filariasis. Albendazole is usually
used as a primary treatment source, but in the case of Lymphatic Filariasis, it
is used as a secondary treatment because while it is used to restrict the
amount of glucose that the worms get, the three different nematodes that cause
LF have adapted to the point where they do not require glucose to live (Micromedex). The most recent treatment
is an antibiotic called doxycycline which is used to treat bacterial
infections, one of which happens to be Malaria. This treatment was not
suggested for LF until 2003, even though the drug had been used for Malaria
before that (Doxycycline).
Part 4: Findings
When looking at both diseases and the supporting
organizations, I found that Malaria gained more international support than
Lymphatic Filariasis. My research began with the supporting organizations
associated with both diseases. Malaria Awareness Day was the first site that
appeared. Malaria Awareness Day was created in 2007 by George W. Bush and is
designated for April 25. On Malaria Awareness Day, many different
organizations, companies, and small businesses have sent nets and shown their
support through donations mostly. One example of these small businesses and
organizations is Choi Kwang Do Martial Art International. On Malaria Awareness
Day, 2007, Choi Kwang Do launched a malaria awareness, fundraising and
education campaign worldwide in partnership with the Malaria Foundation
International (Malaria Foundation
International). Other businesses had rallies to increase the amount of
community support. The largest support group that I found while researching was
the Carter Center Lymphatic Filariasis Elimination Program. The program sends
specialized doctors into Nigeria to help treat the disease and they get drug
donations from companies such as Merck & Co. and GlaxoSmithKline (Lymphatic Filariasis Disease).
During my research phase, I conducted an experiment which
involved a simple survey. Two questions were asked: What can you tell me about
Malaria, and what can you tell me about Lymphatic Filariasis/Elephantiasis
(depending on which name they were familiar with)? The people responding to the
Malaria question answered in a sullen tone, as if they knew about the dying
people in Africa and other affected areas. This meant that they were informed
about Malaria. When the Lymphatic Filariasis/Elephantiasis question was asked,
some people were confused because they never knew this disease existed. Other
people only knew about the symptom that is elephantiasis, not the disease
itself or how it is transmitted. This
data provided an unfortunate, but expected outcome. People know about Malaria
because it is advertised on a daily basis while Lymphatic Filariasis is
promoted through an image search or through opening a supporting organization’s
website by accident.
Malaria is a severe and dangerous disease which causes many
deaths in Third-World countries. The symptoms of Malaria include high fevers,
shaking chills, flu-like symptoms, coma, jaundice, and anemia (Board). Most of these symptoms of
Malaria relate to the symptoms of the common cold, so disability with this
disease is not as severe as what happens if it is left untreated. Morbidity is
very common among patients who are infected with Malaria. There are 300 to 500
million cases of Malaria reported each year, and more than 1 million of those
patients die each year (Board). It is
a very common disease and death associated with it is not uncommon.
Lymphatic Filariasis is more uncommon than Malaria, but it is
not a disease to be taken lightly. Disability involved with LF is the main
reason why it is more commonly known as elephantiasis. Elephantiasis is,
technically, the symptom of LF which causes the thickening of limbs and the
hardening of the skin around the limbs. There are so many psychological
afflictions associated with elephantiasis. Many people are humiliated,
depressed, socially aggressive, feel inadequate, or suicidal because of the
status of their disability. In many cases, the humiliation, depression, and
constant pain cause patients to cut open the swelling limbs in hopes of
relieving the swelling. The afflicted usually end up bleeding to death or
getting an infection from the open wound, so there are more deaths associated
with the psychological effects of the disease than the actual infection itself (Zeldenryk). Morbidity is normally
determined by the severity and deaths due to the infection itself, but there
are more deaths due to how people react to the disability, so morbidity is
quite low because most organizations/research groups do not look at the
psychological side effects. Unfortunately, treating LF and Malaria is becoming
more difficult because the parasites are adapting to the treatments. For example,
the original treatment for Malaria was a drug called Chloroquine and it was the
most common and successful treatment out there, but there are certain areas in
the world where the parasites are becoming resistant and other treatments are
being worked on for the disease, but it is a slow process (Board).
The endemic regions of both of these diseases are very
similar. Because the diseases are mosquito-borne, the endemic regions range
from most of the African continent to South-East Asia because mosquitoes are
the most abundant in those areas. Recently, cases of Malaria and LF have been
reported in Brazil, being the farthest endemic region from the region with the
first cases of Malaria and LF (Africa). Malaria is extremely prevalent in areas
like DRC, Kenya, India, Laos, Cambodia, etc. Lymphatic Filariasis is not as
common as Malaria in those areas, but it is more common than the rest of the
mosquito-borne diseases (Upadhyayula).
Part 5: Conclusions
There are a few factors to look at when comparing these two
diseases. The first factor to look at is the overall danger involved with the
diseases. Malaria definitely outweighs Lymphatic Filariasis when it comes to
danger because the morbidity of Malaria exceeds Lymphatic Filariasis by a
million or so. Lymphatic Filariasis is not a disease commonly associated with
death while Malaria is purposely associated with death so supporting
organizations have a large amount public support.
Lymphatic Filariasis is a purely debilitating disease. The
symptoms and effects of this disease affect the physical quality and
psychological quality of a person. The symptoms of Malaria are more of a burden
on the immune system than the person’s body. Many people with Malaria suffer
through severe flu-like symptoms which can cause massive amounts of pain. In
the best case scenario, one of Malaria’s symptoms is going into a coma and
while a coma is not an optimal outcome, it is better than suffering and then
dying. The symptoms of LF cause immense amounts of pain while, at the same
time, crippling the infected person. Many people believe that they would be
able to survive the pain physically and mentally (at least until they are
treated), but what they do not realize is that this disability inhibits
movement as well as other physical actions. For example, Lymphatic Filariasis
has been known to lower testosterone levels when genitalia have been affected
by the disease. This affliction of the genitalia is what can cause humiliation
and depression which can lead to suicide or the attempted relief turned into an
infection.
In most cases, when high school students are taught about
mosquitoes and the diseases affiliated with them, Lymphatic Filariasis, or even
the common name of Elephantiasis, does not appear in the curriculum. An example
is the Boulder Valley School District high school biology curriculum.
Mosquitoes and the mosquito-borne diseases are part of the curriculum, but
nowhere is there evidence of Lymphatic Filariasis, even Elephantiasis (Jones).
Lymphatic Filariasis is a serious disease that should be
eliminated and is currently in the process of doing so, but US citizens have to
be informed about this disease, not just the symptom of elephantiasis. While
there are supporting organizations, these organizations are not getting the
information out to the public in an efficient way. It should be part of high
school or college biology curriculum because students need to know about this
disease and how it is adapting and migrating. The WHO (World Health
Organization) has passed a resolution stating that Lymphatic Filariasis will be
eliminated by 2020, but in reality, eliminating this disease would entail
causing the extinction of mosquitoes and even then, the parasites will adapt
and find other carriers. For example, a company in the UK called Oxitec has
developed a solution to the mosquito-borne disease known as Dengue fever. The
idea is to genetically modify male mosquitoes with a gene where the offspring
of these mosquitoes require a special dietary supplement provided by Oxitec
alone. The genetically modified males are released into the environment to
reproduce which will cause the eradication of whole populations of mosquitoes.
This solution has not been approved by the US government, as this disease is
the most prevalent in the Florida Keys, because environmentalists will not
allow this company to cause the death of millions of mosquitoes, even though
they’re carriers. This is an example of how similar solutions will kill the
mosquito population just to kill of the disease (Brumfiel). Genetic modification could be the answer to a
self-immunizing mosquito and to preventing parasitic infections through
mosquitoes, but killing off a species just to perpetuate our own is not the
solution.
The people should know about this disease so that they can
prepare for the adaptation of these parasites or so they can help prevent this
disease by, either, donating towards prevention or assisting in researching a
treatment. Malaria will kill a person; Lymphatic Filariasis will make a person
suffer without the possibility of death until it pushes them to commit suicide.
This disease is not something to be taken lightly and information is key to
preparation and assistance in treatment. Finding a way to contain this disease
would be the best solution. This idea applies to Malaria as well. Causing the
extinction of a species (even as dangerous as carriers) just to ensure our
safety is not the right thing to do.
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