Top 10 Most Infectious Diseases
Take the common cold for example. Scientists have tried for centuries to find a cure for it but they have not find a cure. There are more diseases without cure, like the ones that we use to call the “childhood diseases” that have no cure. These diseases are so infectious that there is a high percentage chance that you will die from the complications. Some of them have vaccines that are supposed to protect people from them, some of them have other preventive measures, but the infections from the following list have been major causes of death in history and have been chosen based on fatality rates and impact worldwide. The definition of an infectious disease is given by the fact that the illness is resulted from the presence of pathogenic microbial agents like pathogenic viruses, pathogenic bacteria, fungi, protozoa or multicellular parasites. The transmission of the infectious diseases is made to many different pathways including physical contact with infected individuals, through liquids, food, body fluids, contaminated objects or plain inhalation. Here is a list of the 10 most infectious diseases:
Smallpox is a very contagious disease caused by the variola virus and is believed to have originated 3,000 years ago in India or Egypt, causing a lot of deaths for centuries (30 percent of the ones infected died). In some ancient cultures the death rate because of the smallpox virus was so high that their culture did not allow parents to name their children until they caught the virus and survived it. Among personalities that were killed by smallpox are Queen Mary II of England, Emperor Joseph I of Austria, King Luis I of Spain, Tsar Peter II of Russia, Queen Ulrika Elenora of Sweden, and King Louis XV of France. The disease killed about 30 percent of the people infected, and the ones that survived had marks on their face caused by scratching. No effective treatment has been developed for this disease, and it has some serious side effects, like blindness. Smallpox has two forms: variola major and variola minor, the minor form being more mild than the first one.
Apart from these two, there are also two rare forms of smallpox, haemorrhagic and malignant. The haemorrhagic smallpox, which was also fatal, caused rash accompanied by haemorrhage into the mucous membranes and the skin. The second one was fatal too and caused lesions that did not develop to the pustular stage but remained soft and flat. People that carry the virus during its incubation period cannot infect others, but any contact with a patient after he or she started having fever and in the first week with rash is contagious. Smallpox is not transmitted by insect bites, only by face-to-face contact with an infected person. Vaccines taken up to 4 days after being in contact with an infected person or and before the rash appears proved to be helpful at ameliorating the severity of the disease.
Typhoid fever is a bacterial disease caused by the bacteria named Salmonella typhi. The bacteria can be found in water or food and then spread around to other people. The incidence of the disease has decreased since the 1900s, and now only about 400 cases are reported each year in the United States, most of them in people that have travelled to endemic areas. This means a huge decrease compared to the 1920s, when over 35,000 cases were reported on the American territory. The high risk areas when it comes to contacting typhoid fever are Mexico, South America, India, Pakistan, and Egypt. Each year, more than 13 million people are infected with the bacteria, and 500,000 of them die. Typhoid fever is caught by eating or drinking contaminated food or water, and they can contaminate back the water with their stool, which has a high concentration of the bacteria. Some of the patients are very lucky and suffer a minor illness that goes unrecognized, but they can become carriers of the disease. They have no symptoms to show that they are ill but can be the source of new outbreaks for many years on.
The incubation period of the typhoid fever is about two weeks, and the patient experiences poor appetite, headaches, pain all over the body, fever, lethargy and diarrhea. It can be treated with antibiotics. Before the antibiotics were discovered, the fatality rate was 20% and people died because of the infection, pneumonia, intestinal bleeding or intestinal perforation. With the help of antibiotics, the death rate was reduced to only 2 percent.