Question

Read the following.
a. Malaria is transmitted by a virus.
b. Cholera is caused by Mycobacterium.
c. Salmonella typhi spreads through the soil and water.
d. Varicella causes chicken pox.

Which of the following is true?
A ) a and c
B ) band d
C ) c and d
D ) a and b

Answer 1

Hint:Malaria is a fatal disease caused by a parasite whereas cholera is an infectious disease caused by a bacterium. Salmonella typhi is a bacterium which causes typhoid fever and Varicella is a virus which causes a very contagious disease.

Complete answer:
Statement a is false because malaria is a mosquito borne infectious disease caused by plasmodium, a tiny protozoan. Malarial parasite plasmodium requires two hosts to complete its life cycle; Human and mosquito female anopheles which is the vector/ transmitting agent too. Plasmodium enters the human body as sporozoites infectious form through the bite of infected female anopheles.

Statement b is false because cholera is an acute infectious disease caused by Vibrio cholerae. These may get into a healthy person with contaminated food and water the patients start passing stools frequently which are white like rice-water and get repeated vomiting.

Statement c is true because typhoid is caused by Salmonella typhi ( gram negative bacterium). These pathogens generally enter the small intestine through contaminated food and water.

Statement d is true because the disease is caused by a virus of chicken pox named varicella zoster ( double stranded DNA virus) which is passed out in the discharges of the respiratory tract of an infected person directly as droplets or through contaminated articles used by the patient. It is a mild but highly infectious disease causing slight fever and rash which undergoes changes into vesicles, pustules and finally a dark brown scab which falls off leaving no scars unlike smallpox.

Therefore, statement c and d is true.

Thus, the correct answer is option (C) c and d.

Note:
>Plasmodium was discovered by Charles Laveran. It is an endoparasite ,blood parasite, intracellular parasite ,pathogenic parasite and digenetic parasite.
>Typhoid (Enteric fever) is caused by Salmonella typhi which is a gram negative bacterium.
>The symptoms of typhoid are sustained high fever , weakness, stomach pain, constipation and loss of appetite. Intestinal perforation and death may occur in severe cases.