Common diseases

Ascaris eggs are passed with the faeces of infected persons and contaminate soil, water and plants. A healthy person gets infected through contaminated water, vegetables and fruits.

Pneumonia is caused by bacteria such as Streptococcus pneumoniae and Haemophilus influenzae, which infect the alveoli of the lungs; the alveoli fill with fluid.
Common cold is caused by rhinoviruses, which infect the nose and respiratory passage but not the lungs.
Both are communicable diseases, so the other statements are wrong.

Typhoid fever, caused by Salmonella typhi, is confirmed by the Widal test.
HIV infection is detected by ELISA.