Classification Of Infectious Diseases

The task involves identifying the incorrect statement(s) among the given options related to various infectious diseases. Let's analyze each statement:

1. (A) Intestinal perforation and death may occur in severe cases of typhoid infection. This statement is correct. Typhoid fever, caused by Salmonella typhi, can indeed lead to severe complications such as intestinal perforation and death.
2. (B) Common cold is caused by Rhinoviruses. This statement is correct. Rhinoviruses are the most common viral infectious agents in humans and are the predominant cause of the common cold.
3. (C) Lips and fingernails may turn grey to bluish colour in severe cases of pneumonia. This statement is correct. Cyanosis, which is the bluish discoloration of the skin and mucous membranes, can occur due to poor oxygenation in severe cases of pneumonia.
4. (D) Pneumonia is caused by Salmonella. This statement is incorrect. Pneumonia is primarily caused by bacteria such as Streptococcus pneumoniae, viruses, or fungi, but not by Salmonella, which causes typhoid fever.
5. (E) Typhoid fever could be confirmed by Widal test. This statement is correct. The Widal test is a diagnostic tool used to confirm typhoid fever by detecting antibodies against Salmonella antigens.

Based on this analysis, the only incorrect statement is (D). Therefore, the correct answer is: (D) only.