Chicken pox is caused by a virus and spreads very easily from person to person. If it attacks one person in a class or household, several others persons in the class or household are likely to have it. It has a characteristic rash that is more on the trunk (body) than on the face, feet and hands. It starts with fever, and general feeling of unwell. The rash is the give-away sign. The soles and palms are spared of the rash which dries up after sometime.
Ebola fever is highly contagious and has a high deathrate,about nine out of ten persons affected die if untreated.
It comes into the human population through contact with the blood, secretions, meat and other body fluids of infected animals. It can also happen when animals with the disease (dead or alive) are handled by human beings. These animals include chimpanzee, gorillas, monkeys, fruit bats and antelopes.
Once it enters the human population, it then spreads from person to person through contact with the blood, secretions, and other body fluids including semen of the infected persons. Even poor handling of bodies of persons who died from the disease also help in the spread.
Health workers (doctors, nurses, laboratory scientists etc) can contract the disease if special care is not taken during treatment of the infected person. Infected persons can infect others up to two months after the onset of the disease.
Common cold also called catarrh is very contagious but self-limiting and not life threatening. It is caused by viruses and spreads through sneezing and direct or indirect contact with affected persons. Indirect contact means contact with items contaminated by nasal discharges of affected persons.
Cholera is a disease of the intestines characterised by very frequent and very watery stools and vomiting. It has been responsible for several epidemics (affecting many people simultaneously in an area) and pandemics (affecting a whole country/ whole continent/the world. The period between infection and symptoms varies from 2 to 5 days.
Up to date, Cholera has caused seven pandemics with six occurring before 1923. Most of the six pandemics originated in India and Bangladesh. The seventh epidemic which is apparently still on started in 1961 in Indonesia spreading to South-East Asia in 1962 and the rest of Asia in the following years. In 1970, it reached Europe and some parts of Africa involving about 28 countries in the 1970s before regressing to India and Bangladesh. In 1991, the pandemic spread to South and Central America. In 1993, 80 countries reported cholera epidemics, 2003, – 45 countries with 894 deaths. The disease has drastically declined in developed countries, now mainly in developing/underdeveloped countries of Africa, south – east Asia, South and Central America. Only imported cases are reported in developed countries.
Polio (A.K.A. Poliomyelitis) is an extremely contagious and debilitating disease caused by the polio virus. It occasionally causes death but the infection leads to paralysis, death results if the respiratory muscles are paralyzed. Polio is only found in human and spreads from person to person through food, water and hands contaminated by faeces (stool) containing the virus. Uncovered food can also be contaminated by flies carrying faces containing the virus. The virus attacks the brain and the spinal cord.
Measles is a highly infectious (spreads easily) disease characterized by fever, catarrh, cough and rash all over the body. It is all over the world but more severe in poor countries. Death can occur due its several possible complications ranging from chest infections to infections of the brain. The diseases tends to affect many people at the same time
Syphilis is a very old disease caused by a bacterium. Transmission is mainly during vaginal, anal or oral sexual contact. Also an infected pregnant woman can pass the disease to the unborn child- the bacteria pass through the placenta to the child in the womb. Such infection of the baby could lead to still birth, premature delivery or low birth weight. Sometimes the infected baby maybe born without any problem but if untreated may later develop serious problems like deafness, blindness due to cataract, epileptic attacks etc.
Syphilis has three stages:-primary, secondary and tertiary. The primary stage can be a little sore on the penis or lip or cervix; this may heal spontaneously after a few weeks. The illness then resurfaces under a year as the secondary stage with rash all over the body, sores in the mouth and other features. All these features can disappear spontaneously forever or the disease may reappear in about ten years as the tertiary stage with devastating effects.
Finally the disease can be contracted by accidental contact by care-giver or other close contact of an infected person touching infected materials or sore.