Which of the following is correct statement?

Options

A. Mumps is a bacterial infection which causes swelling in parotid glands
B. Widal test is used for confirmation of infection by Salmonella typhi
C. Koch's disease is mainly caused by toxin tuberculin which is released by Yersinia pestis
D. Polio is caused by ds RNA virus which infect the CNS

Answer

To determine which statement is correct among the given options, we will analyze each one step by step.

### Step 1: Analyze the first option
**Statement:** Mumps is a bacterial infection which causes swelling in parotid glands.
**Analysis:** Mumps is actually caused by a virus, specifically the Paramyxovirus, not a bacterial infection. Therefore, this statement is incorrect.

### Step 2: Analyze the second option
**Statement:** Vidal test is used for confirmation of infection by Salmonella typhi.
**Analysis:** The Vidal test is indeed used to confirm typhoid fever, which is caused by the bacterium Salmonella typhi. This statement is correct.

### Step 3: Analyze the third option
**Statement:** Coase disease is mainly caused by Toxin tuberculin which is released by Yersinia pestis.
**Analysis:** Coase disease refers to tuberculosis (TB), which is caused by Mycobacterium tuberculosis, not Yersinia pestis. Yersinia pestis is responsible for plague. Therefore, this statement is incorrect.

### Step 4: Analyze the fourth option
**Statement:** Polio is caused by DSRNA virus which infected the CNS.
**Analysis:** Poliovirus is a viral disease caused by a virus with single-stranded RNA (ssRNA), not double-stranded RNA (dsRNA). Therefore, this statement is also incorrect.

### Conclusion
After analyzing all the options, the only correct statement is the second one: "Vidal test is used for confirmation of infection by Salmonella typhi."