Biology 9700 · AS & A Level · Infectious diseases

Infectious diseases — practice question

Cholera is a severe, infectious illness caused by the bacterium Vibrio cholerae. A sign of the disease is profuse diarrhoea. V. cholerae O1 and V. cholerae O139 are the two pathogen forms linked to cholera epidemics (large outbreaks). These two forms possess different antigens that can be detected.
(a(i))[2]

Outline the usual treatment that may be used for suspected cholera cases.

(a(ii))[2]

Suggest and explain why this treatment may help to stop a larger cholera outbreak.

(b(i))[2]

Explain how the structure of the monoclonal antibodies in the dipstick enables them to act specifically.

(b(ii))[3]

With reference to Fig. 2.2, state and explain the conclusions that can be drawn from the RDT dipstick results shown for each person.

(ii)[3]

With reference to Fig. 2.2, state and explain the conclusions that can be drawn from the RDT dipstick results shown for each person.

(c(i))[1]

With reference to Table 2.1, calculate the percentage chance that an RDT dipstick correctly confirms that a person with cholera has the disease.

(c(ii))[1]

Using an RDT dipstick to diagnose cholera is much cheaper than culturing the pathogen and needs less technical skill. Suggest one extra advantage of using an RDT dipstick, rather than culture techniques, to diagnose cholera.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: Oral rehydration therapy with solutions made from water, glucose and salts

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