(i) It starts like a cold, with congestion and upper respiratory symptoms, and then progresses to a cough. You have fits of coughing that are so severe that you can't stop or catch your breath.

It's that severe, prolonged cough, and especially the characteristic paroxysms [uncontrolled fits] of cough that trigger physicians to be worried about pertussis and try to confirm the diagnosis.

The symptoms are pretty nonspecific, and so doctors don't always suspect it. Pertussis is high on the list if that whoop is present. The “whoop” sounds like a sharp gasping intake of breath after all the air has been coughed out of your lungs. If it's not, it's likely to go unrecognized because there aren't really other signs and symptoms that are as characteristic.

It spreads through close contact with oral secretions or respiratory droplets. So it's easily spread through the cough, especially when people are in close contact, like living in the same house with a person who has whooping cough. It can also be spread through sneezes - anything that spreads respiratory secretions.

The highest incidence is in infants, and they're also at greatest risk for complications if they develop the disease. In fact, the great majority of fatal cases in the country each year are in infants less than 6 months of age, especially if they're too young to have received their first vaccination.

Whooping cough is a bacterial infection that's highly contagious, and it's also vaccine preventable. Especially in young kids and unvaccinated people, it causes a severe cough, which is the reason for the name, "whooping cough."

It's a bacterial infection, so it can be treated with antibiotics, usually erythromycin or a family of antibiotics like erythromycin. Erythromycin is taken for 2 weeks.

(ii) Tuberculosis

All forms of TB are curable if they are diagnosed and treated in time. Treatment involves taking a combination of drugs for six to nine months because some tuberculosis bacteria are naturally resistant to one or more