A PERSONAL JOURNEY: FROM PARASITE IMMUNOLOGY TO DISEASE CONTROL.
MWELECELE MALECELA
My
career at NIMR is a true story of serendipity rather than design. I
joined NIMR in 1987 after graduating form the University of
Dar-es-Salaam with a B.Sc. in Zoology in 1986. After an extremely
rigorous interview process I was assigned to work at the Amani Center
and to specifically focus on a disease they called Bancroftian
Filariasis. Now I had heard of this disease in my classes at UDSM and
the great tutelage of Dr Parkin but I had know idea what I was going to
do. In my mind I wanted to work on malaria which at the time I thought
was more interesting area of research. So I must say I was quite
depressed as at the time Malaria research had the most resources in
terms of funding and equipment. I was told explicitly that I was to work
to revive the Bancroftian filariasis work at Amani.
As
one who always thrives on a challenge I set off for my long trip up the
Eastern Usambara Mountains to this place they called Amani. The trip
was up a series of undulating hills until we got to a point where I did
not see houses or people. My fear was supressed by the breathtaking
beauty of the drive, the beautiful forest, and the air getting clearer
as we drove up the hill. On arrival at Amani my fears attacked me again,
could I do it how was I expected to live here almost in the middle of
nowhere. I consoled myself by reminding myself that there were several
scientists here and that if they could live here so could I. My dad had a
favourite saying that “its up to you to manage your circumstances” and
that is exactly what I decided to do.
After
several weeks of orientation I was finally designated to work in the
helminthology laboratory where I learnt all about this parasite
Wuchereria Bancrofti, the parasite that spreads bancroftian filariasis. I
learnt to identify microfilariae of Wuchereria Bancrofti and Onchocerca
volvulus. I learnt to dissect mosquitoes for infective larvae and the
lab diagnosis of several parasites including schistosomes, hookworms,
Trichuris etc. At the time mine was a predominantly wormy world and the
people who truly initiated me into the wonderful world of worms were
some great lab technicians and lab assistants who gave me the best hands
on training I ever had. I treasure this training because it has played a
great role in making me who I am today. One lab assistant liked to
remind me that he started working on the month I was born. It didn’t
affect me that they treated me like a kid I just soaked up all the
information that was being given to me and enjoyed every moment. My
family sometimes worried about how i was doing I would phone them from
our old handle phones connected through the tiny exchange to tell them
that I was doing fine and that I actually liked it there.
My
early work included examining the relationship between eosinophilia and
helminth parasites, I also looked at the impact of the trials for
vector control for malaria on the transmission of Bancroftian
Filariasis. I also worked with the late Prof Chris Curtis to control
culicines in Muheza town using polystyrene beads.
I
then went on to do my Msc and PhD at the London School of Hygiene and
Tropical Medicine of the University of London, where I worked on
filarial infection in cats. The cats was an experimental animal model
that provided a lot of current knowledge in the understanding of the
pathogenesis of filarial infection. The work I did focused on
understanding how parasites evaded the hosts immune system and my
findings indicated that there were surface immunoglobulins of the host
that actually protected the parasite. This added to the body of
knowledge on asymptomatic microfilaraemics people who have microfilariae
but have no overt symptoms of the disease.
On
my return I was involved in developing a study to understand
immunoepidemiology of Lymphatic Filariasis Transmission, a study that
took place in sites in Kenya(Kingwende) and Tanzania (Masaika). Several
papers came out of this study which allowed us to getter a better
understanding of the spatial dynamics of LF transmission which would be
very useful in developing effective control programmes.
At
the same time I was involved with developing a strategic plan for the
Elimination of the Lymphatic Filariasis Program of Tanzania. This
followed the WHA resolution in May 1997 that called for the Elimination
of Filariasis as a public health problem. The development of the
comprehensive plan was followed by appointment to be the Director of the
LF programme in 2000. In the year 2000 the LF program was launched on
the island of Mafia and my legacy from the lab to the field to control
came full circle. There is a swahili saying that says “safari moja
huanzisha nyingine” literally translated means the end of one journey is
the beginning of another! In my case however there has been no end to
this journey just different points where I have paused but moved on in
the same direction.
The
LF programme has moved from strength to strength and is now functional
in 53 districts and has reached 13 million people. With the focus now on
neglected tropical diseases the approach has been integrated to include
treatment for schistosomiasis, Soil Transmitted Helminths and Trachoma.
In many ways my interview at the NIMR Headquarters prepared me for a
career in Lymphatic Filariasis Research and Control but like all things
in life I did not know it then. It gave me great pride when President
Kikwete announced that he was going to start an LF Fund to support the
people with the debilitating manifestations of the disease. H.E the
President announced this at the Global Alliance Meeting in Arusha and
this has raised the profile of the patients both in Tanzania and other
countries in Africa. Results from our sentinel site in Tandahima show
that the programme may have succeeded in interrupting transmission in
the district charting it our to be the first district to have attained
interruption of transmission of LF on Tanzania mainland
So
is this a success story? Its a story about a young girl who dreamed
about being a researcher, about a young woman who climbed the hills of
Amani in search of that dream, and the woman who is living that dream
doing research and contributing to the control of a disease she has
worked on all her life! I would say that’s success wouldn’t you!
I
am indebted to so many people who made this journey possible but most
of all my parents Dr John Malecela and the late Mrs. Ezerina Malecela
who told me in no uncertain terms that “yes I could”.
Relevant publications
Malecela
M.N. Baldwin C.I and Denham D.A (1994) Hosts antigen on the surface of
microfilariae of Wuchereria bancrofti and Brugia pahangi.
Transactions
Awarded prize for best presentation
Baldwin
C.I., Medieros F, Malecela M.N. and Denham D.A (1994) Humoral responses
in cats repeatedly infected with Brugia pahangi. Parasite 1,1S
Malecela
(1995): Microfilariae and the immune response in cats repeatedly
infected with Brugia pahangi. Ph.D. thesis, University of London.
P.E.Simonsen,
D.W Meyrowitsch, W.G.Jaoko,M.N.Malecela, D.Mukoko, E.M.Pedersen, J.H.
Ouma, R.T.Rwegoshora, N.Masese, P.Magnussen, B.B.A Estambale and
E.Michael (2001) Bancroftian Filariasis infection,Diseaese and Specific
Antibody Response Patterns in a high and a low endemicity community in
East Africa. Parasite Immunology 23: 373-388
Michael
E., Simonsen P.E., Malecela M., Mukoko D., Pedersen E.M., Rwegoshora
R.T., Meyrowitsch D.W, Jaoko W.G., (2001)Transmission intensity and
immunoepidemiology of bancroftian filariasis in East Africa. Parasite
Immunology No 23. Pp 373-388
Paul
Simonsen,Peter Bernhard, Walter Jaoko, Dan Meyerowitsch, Mwele
N.Malecela-Lazaro, Pascal Magnussen and Edwin Michael (2002) Filaria
Dance sign and subclinical hydrocele in two East African communities
with Bancroftian filariasis. Transactions of the Royal Society of
Tropical Medicine and Hygiene
Simonsen,P.E,
Meyerowitsch, D.W, Jaoko W.G., Malecela, M.N., Mukoko, D., Pedersen,
E.M., Ouma,J.H., Rwegoshora, R.T., Masese.N Magnussen, P., Estambale,
B.B.A & Michael E. (2002) Bancroftian filariasis infection disease
and specific antibody responses patterns in a high and low endemicity
community in East Africa. American Journal of Tropical Medicine and
Hygiene Vol 66(5) pp550-559
Simonsen
P.E Meyrowitsch D.W., Mukoko D, Pedersen E.M., Malecela-Lazaro M.N.,
Rwegoshora R.T., Ouma J.H., Masese, N. , Jaoko W.G., Michael E., (2004)
The effect of repeated half-yearly mass treatment on Wuchereria
bancrofti infection and transmission in two East African communities
with different levels of endemicity. American Journal of Tropical
Medicine and Hygiene No 70 pp. 63-71
Paul
E. Simonsen, Stephen M. Magesa, Samuel K. Dunyo, Mwele N.
Malecela-Lazaro, Edwin Michael (2004) The effect of single dose
ivermectin alone or in combination with albendazole on Wuchereria
bancrofti infection in primary school children in Tanzania. Transactions
of the Royal Society of Tropical Medicine and Hygiene 98,462-472
Simonsen,P.E.,
Meyerowistch D.W., Mukoko,D., Rwegoshora,R.T., Pedersen,E.M., Malecela
Lazaro M.N., Jaoko W.G., and Michael E.(2005) The effect of eight
half-yearly single-doses treatments with DEC on Wuchereria bancrofti
circulating antigenaemia.
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