<P> Measles is a highly contagious airborne virus spread by contact with infected oral and nasal fluids . When a person with measles coughs or sneezes, he releases microscopic particles into the air . During the 4 - to 12 - day incubation period, an infected individual shows no symptoms, but as the disease progresses, the following symptoms appear: runny nose, cough, red eyes, extremely high fever and a rash . </P> <P> Measles is an endemic disease, meaning that it has been continually present in a community, and many people developed resistance . In populations that have not been exposed to measles, exposure to the new disease can be devastating . In 1529, a measles outbreak in Cuba killed two - thirds of the natives who had previously survived smallpox . Two years later measles was responsible for the deaths of half the indigenous population of Honduras, and ravaged Mexico, Central America, and the Inca civilization . </P> <P> Historically, measles was very prevalent throughout the world, as it is highly contagious . According to the National Immunization Program, 90% of people were infected with measles by age 15, acquiring immunity to further outbreaks . Until a vaccine was developed in 1963, measles was considered to be deadlier than smallpox . Vaccination reduced the number of reported occurrences by 98% . Major epidemics have predominantly occurred in unvaccinated populations, particularly among nonwhite Hispanic and African American children under 5 years old . In 2000 a group of experts determined that measles was no longer endemic in the United States . The majority of cases that occur are among immigrants from other countries . </P> <P> Typhus is caused by rickettsia, which is transmitted to humans through lice . The main vector for typhus is the rat flea . Flea bites and infected flea feaces in the respiratory tract are the two most common methods of transmission . In areas where rats are not common, typhus may also be transmitted through cat and opossum fleas . The incubation period of typhus is 7--14 days . The symptoms start with a fever, then headache, rash, and eventually stupor . Spontaneous recovery occurs in 80--90% of victims . </P>

How does globalization increase the changes for pandemic