Overview
>3 billion people live in areas where Malaria transmission is a risk
Mostly tropical and poor conditions for living areas (Africa, South (and SE) Asia and Latin America)
Majority deaths caused by Malaria are in children
Overall infections are targeted at children and females
Malaria is a mosquito-borne infectious disease that affects both plants and animals (but humans are the primary host) caused by parasitic protozoa (unicellular microorganisms) termed “Plasmodium” which specialise further into various types (These various types infect with different levels and types of malaria).
Plasmodium Falciparum is the type which causes highest # of deaths.
The presence of malaria in an area requires a combination of high human population density, high anopheles mosquito population density and high rates of transmission from humans to mosquitoes and from mosquitoes to humans
Symptoms of Malaria can range from mild to a deadly level
Fever, headache, fatigue, anemia (reduced quantity of red blood cells), enlarged organs (liver, spleen), seizures, coma or kidney failure
Immune response is a flu-like syndrome
There is a unique symptom only faced during malaria, which is temperature paroxysm
This is where the patient shivers due to cold and then begins to sweat
Symptoms occur every 36-48 hours
Inside the red blood cells is a protein called, “bilirubin”, which when the blood cell ruptures, these proteins settle under the organism’s skin giving it a yellow shade.
This is called “hemolytic jaundice”
Symptoms usually begin 10-15 days after being bitten by the mosquito
2 classifications for malaria infection:
Uncomplicated:
This can be treated using anti-malarial drugs that kill the plasmodium-borne parasites
Often full recovery
Severe:
Organ problems
Pulmonary diseases or failure
Heart related diseases
Low BP
Severe anemia
Brain diseases
Severe weakness
Unconsciousness/Coma
One thing to note, is that reinfections are extremely common, however do not result in harsh symptoms or effects to the body, as the body has built up immunity to it already. (Elaborate)
The disease is transmitted by Anopheles (female) mosquitoes, which breed in standing water acting as vectors for disease transmission
Vectors are organisms that do not cause the disease themselves, instead spread disease-causing microorganisms from one host to another
Thus this is a non-infectious disease, that cannot spread from person to person, instead only by the mosquito
Mosquitos bite using their proboscis (the pointy mouth)
The mosquito bite introduces the parasites from the mosquito’s saliva into a person’s blood.
The parasites travel to the liver where they mature and reproduce.
Malaria is typically diagnosed by the microscopic examination of blood using blood films, or with antigen-based rapid diagnostic tests.
Methods that use the polymerase chain reaction to detect the parasite’s DNA have been developed, but are not widely used in areas where malaria is common due to their cost and complexity.
Cellular Mechanism
Mosquito gets infected by sucking blood of human infected with plasmodium parasite
Plasmodium (which are now “sporozoites” at this stage) are deposited into the skin while probing (searching) for capillaries, after which these parasites enter the bloodstream through which it travels to the liver, where it infects the liver cells.
Sporozoites reproduce asexually (meaning splitting into two daughter cells) and matures within the liver cell.
The liver cells are infected for ~10-15 days where the cells continue to reproduce and mature
When reproduction and maturation is complete, these reach the stage where they are termed, “Merozoites”.
The merozoites then rupture the liver cells, resulting in the death of the liver cells.
Merozoites then travel from the liver into the bloodstream where it invades the red blood cells.
Merozoites asexually reproduce and mature within the red blood cells, where at this stage, they are in the form of “trophozoites”. At this point the infection is active, leading to a person experiencing symptoms.
This takes two weeks to experience symptoms, as the asymptomatic period is when the sporozoites are reproducing, which also takes ~2 weeks
Similar to the liver cells, the red blood cells eventually rupture and then the merozoites repeat this process several times.
Between step and eight, in the disease cycle diagram, there should be two different arrows branching out or something to separate the two ways the disease can go!!!
However, another type of merozoite invade blood-cells and change their form through biological reactions (in simple terms shape shift), into immature gametocytes (a eukaryotic germ)
These immature gametocytes have male and female gender (which enables reproduction amongst this microorganism)
Male = Spermatocytes
Female = Oocytes
When another mosquito (irrespective of whether it is infected or not) stings a human, it sucks up the red blood cells that contain the male and female gametocytes
Within the gut of the mosquito, the male and female gametocytes reproduce through sexual reproduction (not asexual reproduction) forming a zygote
The zygote then develops into a new plasmodium parasite, stored in the mosquito’s salivary glands.
Diagnosing Malaria often takes three steps:
Conversation
to ask about any abnormalities or whether they have been bitten
Ask about region
Physical examination
Feel for liver enlargement
Laboratory blood tests
Context
Based on 2017 Malaria WHO report:
In 2016, an estimated 216 million cases of malaria occurred worldwide, compared with 237 million cases in 2010 and 211 million cases in 2015
Most malaria cases in 2016 were in the WHO African Region (90%), followed by the WHO South-East Asia Region (7%) and the WHO Eastern Mediterranean Region (2%).
Of the 91 countries reporting indigenous malaria cases in 2016, 15 countries – all in sub-Saharan Africa, except India – carried 80% of the global malaria burden.
The incidence rate of malaria is estimated to have decreased by 18% globally, from 76 to 63 cases per 1000 population at risk, between 2010 and 2016. The WHO South-East Asia Region recorded the largest decline (48%) followed by the WHO Region of the Americas (22%) and the WHO African Region (20%).
Despite these reductions, between 2014 and 2016, substantial increases in case incidence occurred in the WHO Region of the Americas, and marginally in the WHO South-East Asia, Western Pacific and African regions.
Plasmodium falciparum is the most prevalent malaria parasite in sub-Saharan Africa, accounting for 99% of estimated malaria cases in 2016. Outside of Africa, P. vivax is the predominant parasite in the WHO Region of the Americas, representing 64% of malaria cases, and is above 30% in the WHO South- East Asia and 40% in the E
astern Mediterranean regions.
New data from improved surveillance systems in several countries in the WHO African Region indicate that the number of malaria cases presented in this year’s report are conservative estimates. WHO will review its malaria burden estimation methods for sub-Saharan Africa in 2018.
In 2016, there were an estimated 445000 deaths from malaria globally, compared to 446 000 estimated deaths in 2015.
The WHO African Region accounted for 91% of all malaria deaths in 2016, followed by the WHO South- East Asia Region (6%).
Fifteen countries accounted for 80% of global malaria deaths in 2016; all of these countries are in sub-Saharan Africa, except for India.
All regions recorded reductions in mortality in 2016 when compared with 2010, with the exception of the WHO Eastern Mediterranean Region, where mortality rates remained virtually unchanged in the period. The largest decline occurred in the WHO regions of South-East Asia (44%), Africa (37%) and the Americas (27%).
However, between 2015 and 2016, mortality rates stalled in the WHO region of South-East Asia, the Western Pacific and Africa, and increased in the Eastern Mediterranean and the Americas.
~ ½ of World Population is at risk of malaria
>⅔ (70%) of deaths caused by Malaria were in children <5 years old
In 2015, ~303 000 African children died before 5th birthdays
Malaria mortality rates have fallen by 29% since 2010
India
About 95% of the Indian population resides in malaria endemic areas
80% of malaria reported in the country is confined to areas where 20% of population resides – in tribal, hilly, hard-to-reach or inaccessible areas
4th highest number of deaths caused by Malaria are from India (7%).
India is the poorest performer in the South East Asian region (SEAR). The number of cases in it highest endemic state, Odisha, shot up in 2016, doubling the number from 2013. Meanwhile, neighbouring Sri Lanka was declared malaria free in 2016 by the WHO, as was Kyrgyzstan.
India also had the lowest funding average per person at risk, from 2014 to 2016 in the region. While it’s on track to reduce malaria cases by 20 to 40 percent by 2020, most other SEAR countries will hit over 40 percent reduction.
Prevention and Treatment
Treatment
Antimalarial Drugs
To prescribe these drugs, it is imperative to know the type of plasmodium that is causing malaria in the organism
Need to know whether it is uncomplicated malaria or severe malaria
What symptoms is the patient facing
Parasite resistance
E.g. Patient A and Patient B
Patient A = Uncomplicated Malaria (At home)
Antimalarial drugs can be taken in pill form at home
Just to briefly remind the disease cycle, liver cells → red blood cells→ reproduction of trophozoites and merozoites
The antimalarial drugs can be implemented in any of these phases
Treated with combinational therapy (~2-3)
A variety of drugs must be used, to avoid drug resistance from building up
This has become a big issue in some parts of the world
Need to address this, otherwise one day there will be no effective antimalarial drugs left for usage
The recommended combination of drugs to be used is termed as “Artemisinin Combination Treatment/ Therapy (ACT)”.
Artesunate is the drug used, derived from a plant named, Artemisinin
This drug creates a highly toxic environment for the plasmodium and interferes with the proteins on its surface interfering with its movement and absorption of nutrients
Artesunate is effective against all types of drugs, and has low resistance globally
However, another drug must be used to increase the effectiveness of medication
The most common partner to Artesunate is Mefloquine
Disrupts the acid-base balance of the parasite
Another used combination is Sulfadoxine + Pyrimethamine
Disables the parasites from replicating DNA and reproducing
This is mainly for falciparum
For Plasmodium vivax, which is also quite infectious
The drugs artesunate can be used again, or there are different types of drugs
I was mentioning earlier the drug resistance
There is a drug called “chloroquine” which faces critical drug resistance in the S.E.A. region
Patient B = Severe Malaria (Hospitalised)
Requires more care than Patient B, because is facing more issues such as seizures or has slipped into coma
For this, antimalarial drugs cannot just be taken in pill form, instead must be injecting into the bloodstream for more
Just to briefly remind the disease cycle, liver cells → red blood cells→ reproduction of trophozoites and merozoites
The antimalarial drugs can be implemented in any of these phases
In severe cases, all the medication that is taken in uncomplicated cases will be taken, however straight from an I.V. (explain what is an I.V.) into the bloodstream
Apart from this, additional care will be required, as in severe cases the patient may be suffering from seizures or heart issue
Require respiratory support along with fluid and electrolytes supply
Normally, with proper treatment there is full recovery even in majority of severe cases
No vaccine for malaria as of now
Prevention
Firstly, the factors which allow the spread of malaria endemic are the following:
Human population density
Mosquito population density
High rates of transmission between the two groups
Methods used to prevent malaria include medications, mosquito elimination and the prevention of bites
If any of these variables are decreased sufficiently, then malaria can be eradicated
It is not possible to reduce the human population density
However, the mosquito population can be lowered through vector control
Vector control is a possible form of preventing malaria.
For individual protection the following are used:
Insect Repellent (Repel do not kill)
To apply on clothes and sometimes skin
These include picaridin and DEET
Coils
Can reduce the breeding sites of the malarial insects
Breed in standing water
So this water can be drained out, or chemicals can be added to it
Insecticide Treated Mosquito Nets (ITNs)
~70% chance of protection
Used over beds in rural areas (Explain)
Indoor Residual Spraying (Used in enclosed areas such as homes and buildings)
Fumigation outdoors
All insecticides help to paralyze mosquitoes
In places like Singapore, there is a program, termed “Mozzie Wipe Out”
This outlines 4-6 steps that individuals should take to keep their surroundings clear of danger
To reduce the transmission rates of the disease (Change individual behaviour)
Wear full sleeved clothes and pants
Community participation and health education strategies promoting awareness of malaria and the importance of control measures have been successfully used to reduce the incidence of malaria in some areas of the developing world
Get regular check ups, as if someone is infected with malaria, then mosquitoes that bite that person will have the parasites and pass it on to an
other individual
Case Study
3 main case studies have analysed:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3294179/
Published in 2011, this case study provides a overview of Malaria all over India which is my region of focus in this project.
Malaria cases and changing species pattern in India during the years 1995–2010. The total number of reported malaria cases has decreased since 1995, primarily through a reduction in the number of reported P. vivax cases. As of 2010, there is a 1:1 ratio of P. falciparum to P. vivax cases.
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https://www.gov.uk/government/case-studies/battling-malaria-in-india
Published in April 2011, this case study focuses on the rural population of India, where Malaria is most prevalent. This article is based upon an interview by the British Government Officials (ensuring credibility) on a women living in Labangi village in India. This article elaborates upon the poor infrastructure and attempts to curb the endemic in India. This articles also explains how people in rural India are uneducated about the disease, thus definitely not knowing how to prevent or treat it. This article speaks about Department for International Development India (DFID India), who are educated the masses and increases preventive measures for the endemic.
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https://pdfs.semanticscholar.org/4b52/13ac797148e92ee1183c4cad99ba8defb66a.pdf
Published in 2014, this article refers to Malria in India with special reference to tribal areas (particularly in the East of India).
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Sustainability
Economic Factors
When analysing the Malarial endemic, scientists often refer to the socio-economic stature of people, as an indicator
This can be used as an effective indicator especially when researching about India, due to the mammoth wealth gap
Poverty increases the probability of malarial cases and death as a result of malaria
This is as foremost their financial position disables them from adopting preventive measures and later treatments for the disease
In India, ~70% of the population lives in rural areas, and a lot in poverty facing the same problem
It was theorized that the economic slowdown of Southern U.S.A. Occurred partly due to malaria
In this case, poverty is not due to malaria, instead malaria is due to poverty
Environmental factors
Environment plays a big role in Malaria
As stated above mosquitoes breed in standing water thus in conditions where there is poor maintenance, this disease is prevalent
Also, malaria has an effect on the surroundings, as when people are infected, the plasmodium can be sucked by a mosquito and transmitted to another individual. In such cases, endemic can spread rapidly
The parasites which are also considered part of the environment, are causing problems for modern day scientists, due to drug resistance building up globally
This is an effect and a potential cause possibly for calamity
Global warming is expected to increase the prevalence and global distribution of malaria, as elevated temperatures provide optimal conditions for parasite reproduction.
There is prevalent, especially in some parts of India which are already optimal sites for parasite reproduction, resulting in the nearby population to be at risk
Social Factors
People also must be taking preventive and treatment measures
However, for this people must be educated about the vitality of taking these measures