Smallpox was a systemic disease, officially eradicated since 1979 (WHO), caused by infection with the Variola major virus, whose only reservoir was infected humans.
Chikungunya is a viral disease transmitted by Aedes mosquitoes to humans. The word ‘chikungunya’ means 'that which bends up', an allusion to the posture of the suffering patients. The most common symptom is joint pain.
Campylobacteriosis is a diarrhoeal disease caused by Campylobacter bacteria, found in animals such as poultry, cattle, pigs, wild birds and wild mammals
Diphtheria is spread through droplets from coughing or sneezing. Most often the disease causes a sore throat and low grade fever in the first few days of the illness.