MALARIA – A
MASTER OF DISGUISE
Maryknoll priests working in northern Uganda witness repeated
outbreaks of malaria annually every June and July. Why is this disease so difficult to control,
let alone eradicate?
Worldwide, 88% of malaria infections and 90% of deaths occur
in Sub-Saharan Africa. Uganda can
illustrate the challenges to controlling this disease. With 42 million people,
100% of the population is at risk for malaria, the leading cause of death is
malaria and 50% of these deaths are in children less than age five.
In Uganda, treatment of a single episode of malaria can cost
US$9. Additionally, a worker may miss 5-20 days of
work and cognitive function in children can be impaired by as much as 60%. Often, people are infected multiple times
annually, further decreasing productivity.
A poor family may spend 25% of their household income on prevention and
treatment.
Uganda began a targeted malaria control program in 2018 with
the goal of reducing malarial deaths by 40% in 2020 and 75% in 2025. Total deaths in 2017 numbered 5,100 and
decreased to 3200 in 2018. However, from June 2018 to June 2019 the number of
cases increased from 1 million to 1.4 million, an upsurge of 40%, mainly in
West Nile, North and Central regions.
The prevalence in Kampala was about the same, but severe cases increased
by 60%. The National Malaria Control
Plan (NMCP) identifies the reasons for these increases to be:
1. Climate change
2. Failure to use Long-Lasting
Insecticide Treated Nets (LLIN)
3. Failure to use
prevention in highland areas where people have less immunity
4. The rainy season
is April to June when the mosquito vectors increase
The NMCP provides mass distribution campaigns of LLIN to the
entire population every three years via programs for pregnant women, childhood
immunization programs and schools. Unfortunately,
only 64% of pregnant women and 62% of children less than age five have nets,
the nets are not used properly and they may be of poor quality and tear easily.
Movement of people who are uninfected, or partially infected,
leads to outbreaks when they enter an endemic zone, since they have decreased
immunity and poor access to treatment.
This could be a significant factor in northern Uganda where refugees
have migrated from South Sudan. This
marginalized sector of Uganda has been greatly impacted by the re-occurring,
multifactorial stresses of war and insecurity in South Sudan.
The NMCP attempts to provide malaria prevention to pregnant
women by giving two doses of Intermittent Preventative Therapy (ITP) with
sulfadoxine/pyrimethamine (SP). However,
only 45% of pregnant women attended two clinics before delivery and received
both doses. The NMCP also supports prevention,
diagnosis and treatment through Integrated Community Case Management
(ICCM).
Not surprisingly, drug resistant strains have developed. One study in Gulu, northern Uganda in 2018 reported
that the resistance may have originated in Africa. In south east Asia, resistance is well
documented to first line drugs, occurring in 50-90% of treatment regimens in
some regions. There is great fear this
will spread quickly to Africa where treatment options are limited.
China has a project to eradicate malaria in Kenya since
2017. It uses an artemisinin drug
enhanced with piperaquine to give mass treatment of the population and attempts to eradicate the human reservoir of the parasite. The drug costs $17 per dose and resistance to
piperaquine has already developed in East Asia.
Evidence for the success of this approach is questionable. There is concern that it could also lead to
development of more resistance.
Development of a vaccine began in the early 1980s and progress
is slow. Malaria is a parasite and most
vaccines have been made against bacteria and viruses. Vaccines for parasites require a different
process. The malarial parasite has four
different species with constantly changing antigens, the markers used to make a
vaccine. The parasite changes its
appearance as it moves from the blood, to the liver, and then again to the
blood. It is a master of disguise.
A Malaria Vaccine Technology Roadmap has been developed by
more than 230 experts in 100 organizations from 35 countries. Their goal is to develop a malaria vaccine by
2025 that would protect against 80% of clinical disease for more than four
years. The RTS,S/A S01 vaccine is the
most advanced candidate for use and was 47% effective in reducing mortality in
Phase III trials in seven sub-Saharan countries. The Pilot Project Phase IV trials began in
2018 in Kenya, Ghana and Malawi, with hopes that it will bring a new vaccine
into production when completed.
If the malaria parasite develops resistance to treatment
regimens and the mosquito develops resistance to vector control mechanisms,
eradication is impossible. Control of
the disease can be successful, but it requires long-term strategies that target
various points of infection and transmission.
The challenges are significant and will require uncompromising
commitment for the long road ahead.
Today begins the SEASON OF CREATION which continues to October 4th, the Feast of St. Francis. I accept that even mosquitoes have their place in creation but we must all learn to live in harmony!!!
PEACE OF THE CHANGING SEASONS TO YOU!!!
https://www.pmi.gov/docs/default-source/default-document-library/malaria-operational-plans/fy19/fy-2019-uganda-malaria-operational-plan.pdf?sfvrsn=3
https://wwwnc.cdc.gov/eid/article/24/4/17-0141_article
https://www.npr.org/sections/goatsandsoda/2019/07/22/742674941/study-malaria-drugs-are-failing-at-an-alarming-rate-in-southeast-asia
https://www.who.int/immunization/research/development/malaria/en/
https://www.ndm.ox.ac.uk/simon-draper-progress-in-malaria-vaccine-research
https://www.malariasite.com/malaria-vaccines/
https://www.kbc.co.ke/china-adopts-strategy-to-eradicate-malaria/
https://allafrica.com/stories/201908190111.html
https://www.theeastafrican.co.ke/scienceandhealth/Uganda-war-on-malaria/3073694-5238934-hkj8l1z/index.html
