MALARIA : A KILLER DISEASE OF THE TROPICS

Hello steemians, Hope we are all good? Well I have been so busy with school stuffs and its been really hectic doing a lot of baby stuffs. Last week was world malaria day so I decided that I will be doing a write up on malaria and everything about malaria.

WHAT IS MALARIA?

Malaria is an infectious disease caused by the bite of an infected female anopheles mosquito.As at 2015 there were 214 million new cases of malaria resulting in 438,000 deaths.The majority of cases (65%) occur in children under 15 years old. The reason for this is that they have not developed enough immunity.

WHAT CAUSES MALARIA?

The main cause of malaria is infection from a female anopheles mosquito that is infected with plasmodium species.

source

There are several risk factors that are capable of predisposing one to malaria. They include;

• Living in areas where there is stagnant water. Stagnant water helps the larva of the mosquito to grow. Hence, stagnant water is a breeding site for mosquitoes.
• Inadequate use of Mosquito net or not using insecticide treated net.
• living in areas that are mosquito infested without adequate measures to kill them as in the use of insecticide.

THE FEMALE ANOPHELES MOSQUITO

There are different species of mosquitoes but the female anopheles mosquito is the main vector that causes malaria.
The female anopheles mosquito takes blood meal in order to produce eggs. This necessity is the link between humans and mosquitoes. The female anopheles mosquitoes is infected with plasmodium species. While taking the blood meal, humans get infected with plasmodium species in the mosquito.
To know more about the female anopheles mosquito click here

THE PLASMODIUM PARASITES

There are five species of the plasmodium parasite that cause malaria. They are
Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi
!
Plasmodium falciparum has been implicated as the cause of severe malaria. The plasmodium knowlesi has been reported to have caused severe malaria.

THE LIFECYCLE OF PLASMODIUM

The lifecycle is divided into two phases in man

1. The erythrocytic phase
2. The exo-erythr
   Life cycle includes a sexual phase (sporogony) which occurs in the mosquito and an asexual phase (schizogony) which occurs in man.

Man is the intermediate host. In humans, inoculation of sporozoites from an infected female Anopheles mosquitoe occurs during a blood meal.
These disappear into the hepatocytes within 30-60 minutes and develop into schizonts within which multiple nuclear divisions occur, each surrounded by a small piece of cytoplasm.
Development in the liver requires about 7-14 days (exo-erythrocytic schizogony).
In P. vivax and Ovale, dormant forms called hypnozoites persist in the liver.

The mature schizont then ruptures to release numerous merozoites into the blood stream (erythrocytic schizogony begins).

These invade red blood cells and then differentiate into trophozoites, then to schizonts within which multiple nuclear divisions occur, each surrounded by a small piece of cytoplasm

When the mature schizont ruptures, numerous merozoites are released.

These either re-invade other RBCs to continue the erythrocytic cycle or give rise to macro(female) and micro(male) gametocytes.

The erythrocytic phase takes about 36-48 hours for P. falciparum, 48hours for P.vivax and P. ovale, 72hours for P. malariae and 24hours in P. knowlesi
.

HOW CAN YOU KNOW YOU HAVE MALARIA?

Diagnosis of malaria can be done in two ways.

1. Laboratory diagnosis
2. Clinical diagnosis
   Laboratory diagnosis is what the world health organization advocates for the diagnosis of malaria.
   The gold standard for laboratory diagnosis of malaria is by thick and thin film using Giemsa stain
   The thick film helps to check for parasitemia(parasite load). The thin film is used for speciation. Speciation means finding out the particular specie implicated in the illness.

HOW DOES MALARIA PRESENT CLINICALLY?

The features of malaria are not specific to malaria. As a result malaria is a diagnosis of exclusion. This goes to say that skilled personnel have to exclude other causes of the symptoms before making a diagnosis of malaria. The symptoms include;

1. Fever
2. Joint pain
3. Headache
4. Malaise
5. Nausea
6. Vomiting
7. Sour taste
8. Generalized body pains
   As it is seen above, fever could occur due to a lot of illness apart from malaria. If a person has a urinary tract infection (UTI), the patient can present with fever. Also, a respiratory tract infection could also present with fever. The same goes for joint pain and other symptoms.

SEVERE MALARIA

Severe malaria is a type of malaria with life threatening symptoms.
Severe malaria appears to occur more in the following group of people;
-Children under the age of 5

• Pregnant women
• Patients with sickle cell anemia
• people return or coming to malaria stable countries.
• people who have had splenectomy
  The symptoms include;

1. Prostration meaning that the person is too tired or weak to do anything. Some babies find it difficult to sit.
2. Cerebral malaria which can be said to be unarousable coma occurring for more than 30 minutes.
3. Acute kidney failure refers to a reversible injury to the kidneys. Here the kidneys might fail to produce urine
4. Severe Jaundice
5. Hyperpyrexia which can be said to be a rectal temperature of >40°C or an axillary temperature greater than 39.5°c
6. Shock which could present with hypotension, palllor and rapid thready pulse.
7. Hyperparasitemia
8. Pulmonary edema
9. Blood clotting disorders like disseminated intravascular coagulopathy
10. Electrolyte and acid-base balance of which stones the pH might fall below 7.2
11. Severe anemia which might be less than <5.0g/dl
12. Hypoglycemia which means low blood glucose.
    These symptoms are capable of causing death in patients. Hence prompt treatment must be done once noticed.

TREATMENT

The treatment for malaria can be divided into;

1. Treatment of uncomplicated malaria
2. Treatment of complicated malaria

TREATMENT OF UNCOMPLICATED MALARIA

WHO advocates that uncomplicated malaria should be treated by the use of artemisinin combination therapy commonly known as ACTs.
The common combinations are;
-Artemether+ lumenfantrine

• Artesunate+ Amodiaquine.
  There are others that can be used. To see other combinatioms click source

TREATMENT OF COMPLICATED MALARIA

The aim of this treatment is to save life. The treatment modality involves the use of IV artesunate or IV chloroquine for the treatment of severe malaria.

PREVENTION

The prevention of malaria can be divided into three stages.

1. Host control
2. Vector control
3. Parasite control
   Host control involves control measures that aims at protecting the host from malaria like use of mosquito repellent creams, insecticide treated net and sometimes wearing of bright colored clothes.
   Vector control involves control measures aimed at reducing the amount of vectors in the environment. Vector control includes use of insecticide, functional drainage that can prevent stagnant water.
   Parasite control involves the use of drugs to kill the parasite. The use of prophylactic medications such as sulfadoxime pyrimethamine.

CONCLUSION

In conclusion, Malaria is a very deadly disease.
It should prevented in both newborns and pregnant women because of reduced immunity.

SOURCES

Wikipedia
CDC
Davidson textbook
Paediatrics and childhealth in the tropics