Malaria vaccine is used to prevent malaria. The only approved vaccine as of 2015 is RTS, S(Mosquirix). It requires four injections and has relatively low efficacy (26-50%). Due to this low efficacy, WHO does not recommend the use of RTS, S vaccine in babies between 6 and 12 weeks of age 

Kala-azar or visceral leishmaniasis is caused by Leishmania donovani, which is transmitted by the vector Phlebotomus (sand fly). Infection may occur in the endothelial cells, bone marrow, liver, lymph glands and blood vessels of the spleen. Symptoms of Kala-azar are weight loss, anaemia, fever, enlargement of spleen and liver

Causative agent - Alpha virus
Infection site - Nervous system
Mode of transmission - Aedes aegypti (Mosquito)
Symptoms - Fever; headache, joint pain, and swelling.

The intake of certain drugs for a purpose other than their normal clinical use in an amount and frequency that impair one's physical, physiological and psychological functions is called drug abuse.

Several people complain of stomach discomfort or pain and trouble with bowel movements, causing diarrhoea. This is called irritable bowel syndrome and caused by stress or other illnesses

(i) Alcohol interferes with the ability of the liver to break down fat. Over time fat accumulation and high levels of alcohol destroy the liver cells and a scar tissue grows in the place of dead cells. This scarring of the liver is called "Liver cirrhosis ".
(ii) Alcohol irritates the stomach lining due to the production of excess acid leading to ulcers.
(iii) Excessive alcohol use weakens the heart muscle, causing scar tissue to build up in the cardiac muscle fibers. As a result, heavy drinkers have an increased risk of high blood pressure, stroke, coronary artery disease and heart attack.

Tobacco is smoked, chewed and used as snuff. It increases the carbon monoxide content of blood and reduces the concentration of haem bound oxygen, thus causing oxygen deficiency in the body.

Morphine is extracted from flowers of the poppy plant. It is one of the strongest pain killer and is used during surgery. It is the most widely abused narcotic drug which acts as a depressant and slows down body functions.

According to the World Health Organization (WHO), hygiene refers to "conditions and practices that help to maintain health and prevent the spread of diseases."

(i) Commonly called filarial worm. It is found in the Iymph vessels and lymphnodes of man.
(ii) Wuchereria bancrofti is sexually dimorphic viviparous and digenic. The life cycle is completed in two hosts, man and the female Culex mosquito.
(iii) The accumulation of the worms block the lymphatic system resulting in inflammation of the lymph nodes.
In some cases, the obstruction of lymph vessels causes elephantiasis or filariasis of the both scrotum and mammary glands.

Dermatomycosis is a cutaneous infection caused by fungi belonging to the genera Trichophyton, Microsporum and Epidermophyton.

(i) Ponds, drainage ditches and other permanent bodies of water can be stocked with fishes such as Gambusia which feed on mosquito larvae.
(ii)  Preparations containing Bacillus thuringiensis can be sprayed to kill the mosquito larvae since it is not toxic co other forms of life.

Viral diseases are generally classified into four types on the basis of the symptoms produced in the body organs.
(i) Pneumotropic diseases (Eg: respiratory tract infected by influenza)
(ii) Dermotropic diseases (Eg.skin and subcutaneous tissues affected by chicken pox and measles)
(iii) Viscerotropic diseases (Eg: blood and visceral organs affected by yellow fever and dengue fever)
(iv) Neurotropic diseases (Eg: central nervous system affected by rabies and polio)

Inside the human RBC, the merozoite of plasmodium begins to develop as unicellular trophozoites. The trophozoite grows in size and a central vacuole develops pushing them to one side of cytoplasm and becomes the signet ring stage.