Malaria Chain of Infection

Host

Susceptibility

Pathogenic

Microorganism

Malaria is the causative agent (i.e. entity that causing disease), which is a biological protozoan that lives off other organisms, in some cases humans, a (microbe/ organism) too small to be seen with the naked eye. ((CDC), 2016)

Host susceptibility Depends upon:

Genetic factors

A. People who have the sickle cell trait (heterozygotes for the abnormal hemoglobin gene HbS) are relatively protected against

B. People who are negative for the Duffy blood group have red blood cells that are resistant to infection

General resistance

A. After repeated attacks of malaria some people may develop a partially protective immunity

Specific acquired immunity (natural or thru vaccinations)

• None

Behavioral Factors include:

• Malnutrition

• poor health

• Poor rural populations that cannot afford the housing and bed nets that would protect them from exposure to mosquitoes.

• Migrations (voluntary or forced) and tourism

((CDC), 2016)

Chain of Infection

Reservoir

Means of Entry

The reservoir of an infectious agent is the habitat in which the agent normally lives, grows, and multiplies. Malaria two hosts are essential (the female mosquito and human), In the female mosquito’s salivary glands, the parasite multiplies and grows and in humans, the parasites grow and multiply first in the liver cells and then in the red cells of the blood. Thus, causing the human to become ill and show exhibit signs/symptoms of illness. While the mosquito is free of developing any illness or display any signs of infection/illness at all.((CDC), 2016)

When a mosquito (vector) feeds on a human host infected with malaria this initiates the “Means of Escape” & the “Means of Entry”. Gametocytes are picked up by a female mosquito during the blood meal, which are stored in the mosquito's salivary glands starts the cycle of growth and multiplication. After 10-18 days, the parasites, now (as "sporozoites") in the mosquito's salivary glands are released when mosquito feeds on another human. The sporozoites are injected with the mosquito's saliva in the new host’s (human’s) blood stream and starting another human infection when they parasitize the liver cells.((CDC), 2016)

SIDE B

SIDE A

The chain of infection is the result from the three epidemiological models, which is interaction of agent, host, and environment.

Transmission occurs when the agent leaves its reservoir (i.e.host) through a portal of exit, next conveyed by some mode of transmission (i.e. vector), and enters through an appropriate portal of entry to infect a susceptible host. This sequence is called the Chain of Infection.

Mode of Transmission

Means of Escape

Malaria’s means of transmission is a direct transmission “Vector Borne” from the injection of saliva during the bite of a female mosquito. ((CDC), 2016)

When a mosquito (vector) feeds on a human host infected with malaria this initiates the “Means of Escape” & the “Means of Entry”. Gametocytes are picked up by a female mosquito during the blood meal, which are stored in the mosquito's salivary glands starting the cycle of growth and multiplication. After 10-18 days, the parasites, now (as "sporozoites") in the mosquito's salivary glands are released when mosquito feeds on another human. The sporozoites are injected with the mosquito's saliva in the new host’s (human’s) blood stream and starting another human infection when they parasitize the liver cells.((CDC), 2016)

Malaria Chain of Infection

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References

(CDC), C. f. (2016, March 01). Biology of Malaria. Retrieved from Centers for Disease Control and Prevention (CDC): https://www.cdc.gov/malaria/about/biology/index.html