The objective is to identify the erroneous statement(s) among the provided options concerning infectious diseases. Examination of each statement:
- (A) Severe typhoid infection can result in intestinal perforation and fatality. This statement is accurate. Typhoid fever, attributed to Salmonella typhi, can indeed lead to serious complications, including intestinal perforation and death.
- (B) Rhinoviruses are responsible for the common cold. This statement is accurate. Rhinoviruses are the most prevalent viral infectious agents in humans and are the primary cause of the common cold.
- (C) In severe pneumonia cases, lips and fingernails may exhibit a grey to bluish hue. This statement is accurate. Cyanosis, characterized by the bluish discoloration of skin and mucous membranes, can manifest due to inadequate oxygenation in severe pneumonia cases.
- (D) Salmonella causes pneumonia. This statement is incorrect. Pneumonia is predominantly caused by bacteria like Streptococcus pneumoniae, viruses, or fungi, not by Salmonella, which is the causative agent of typhoid fever.
- (E) The Widal test can confirm typhoid fever. This statement is accurate. The Widal test is a diagnostic method employed to confirm typhoid fever by detecting antibodies against Salmonella antigens.
Following this analysis, statement (D) is the sole incorrect assertion. Consequently, the correct answer is: (D) only.