Question

Epidemiologists study the occurrence and transmieeion of human diseases on a global scale. this is no easy task since pathogens, or disease-causing organisms are everywhere. it is virtually impossible to avoid coming into contact with a potentially pathogenic microorganism in the modern world.
INFLAMMATION: PLEASE provide background about a disease-causing microbe. is it a virus, bacterium, etc.? what are the symptoms of the disease.
Describe the impact of this microbe on human health. why would this disease be of concern to epidemiologists? what is the prevalence of the disease in the human population?
describe any treatments available for the disease. include vaccinations and chemotherapeutic treatment options.
in your option, would the innate immune system or the adaptive immune system be more effective at fighting off this infection?
this must be written 800 to a 1000 words.

thank you

Answer 1

Infectious diseases are caused by microbes. Most microbes are useful for us but some of them cause diseases in humans, animals, and even plants. We call such microbes pathogens or germs.

Germs cause various types of diseases and these diseases are classified on the basis of the pathogens that cause it.

So, infectious diseases can be classified as --

* Bacterial diseases eg typhoid, pneumonia, dysentery etc

* Protozoan diseases eg malaria, dengue

* Fungal diseases eg ringworm

* Viral diseases eg polio, influenza, common cold etc.

Let us discuss the cause, symptom and treatment of the disease, malaria.

Malaria is a protozoan disease and is quite common in tropical regions. Despite all the efforts, it has not been eradicated and is a cause of death for a large population of people in different parts of the world.

It is caused by a protozoan Plasmodium, the common species being P.vivax, P.malariae, and P. falciparum.

The vector of these germs is the female Anopheles mosquito which transfers the infectious stage, called sporozoite, from infected to healthy people.

When a carrier female Anopheles mosquito bites a healthy person, it transfers the sporozoites through its saliva.

The sporozoites reach the liver cells through the blood and begin to multiply asexually.

As they increase in number, they attack the red blood cells. In the RBC too, they multiply asexually and cause them to rupture.

The ruptured RBCs release a toxin called hemozoin, which causes high fever accompanied by severe chills and shivering.

Some of the germs develop into gametocytes in the RBC. When a female Anopheles mosquito bites such a person, it sucks the gametocytes along with the blood.

Once inside the mosquitoes body, the gametocytes reach its stomach walls, where they fertilize and multiply sexually.

The sporozoite stage of the germ is produced and stored in the salivary glands of the mosquito. When it bites a healthy person, the sporozoites are transferred and the whole cycle is repeated again.

Malaria is a cause of concern for epidemiologists all over the world. All measures to eradicate it have failed.

Treatment of an infected person is done by administering drugs like quinine and chloroquine.

Malaria can be prevented by killing mosquitoes by spraying chemicals and by using insect repellants, mosquito nets etc. Sanitation is also one way to stop the mosquitoes from breeding. Since the female mosquitoes lay eggs in stagnant water, care should be taken that there are no uncovered drains or puddles in the area.

Many protozoa cause infections that often follow chronic courses, owing to coevolution between parasite and host immune system. The survival and transmission of pathogenic protozoa depend on their ability to evade or subvert host's innate and adaptive immune responses. It is a great challenge to researchers in immunology and parasitology to develop strategies that could favor immunity against protozoan parasites and prevent their evasion, chronic or recurrent infections, and associated pathologies.

A lot of research is still being done and researchers have proposed a mathematical model to predict malaria transmission in endemic areas under drug pressure, taking into account induction of relapse by P.VIVAX infection, which confers the ability to boost adaptive immunity and prevent clinical malaria.

There is no vaccination yet developed to prevent malaria and the only way is to stop the Anopheles mosquitoes from breeding so that the vector-host of the germ is not available.

It is interesting to note that people suffering from sickle cell anemia do not get infected by thy malaria parasite. This is because the altered shape of the RBCs in such people does not enable the protozoa to complete its sporozoite stage.