In underdeveloped nations with high rates of malnutrition and poor healthcare, fatality rates have been as high as 28%. In immunocompromised persons (e.g., people with AIDS) the fatality rate is approximately 30%.Even in previously healthy children, measles can cause serious illness requiring hospitalization. One out of every 1,000 measles cases progresses to acute encephalitis, which often results in permanent brain damage. One to three out of every 1,000 children who become infected with measles will die from respiratory and neurological complications. Cause
Measles is caused by the measles virus, a single-stranded, negative-sense, enveloped RNA virus of the genus Morbillivirus within the family Paramyxoviridae.The virus is highly contagious and is spread by coughing and sneezing via close personal contact or direct contact with secretions. Measles is the most contagious transmissible virus known. It remains infective for up to two hours in that airspace or nearby surfaces. Measles is so contagious that if one person has it, 90% of non-immune people who have close contact with them (e.g., household members) will also become infected. Humans are the only natural hosts of the virus, and no other animal reservoirs are known to exist, although mountain gorillas are believed to be susceptible to the disease.
Cases were first reported in Washington state in January, with an outbreak of at least 58 confirmed cases most within Clark County, which has a higher rate of vaccination exemptions compared to the rest of the state; nearly one in four kindergartners in Clark did not receive vaccinations, according to state data. This led Washington state governor Jay Inslee to declare a state of emergency, and the states congress to introduce legislation to disallow vaccination exemption for personal or philosophical reasons. In April 2019, New York Mayor Bill de Blasio declared a public health emergency because of "a huge spike" in cases of measles where there were 285 cases centred on the Orthodox Jewish areas of Brooklyn in 2018, while there were only two cases in 2017. There were 168 more in neighboring Rockland County. Other outbreaks have included Santa Cruz County and Butte County in California, and the states of New Jersey and Michigan. As of April 2019, there have been 695 cases of measles reported in 22 states. This is the highest number of measles cases since it was declared eradicated in 2000. From 1 January, to 31 December 2019, 1,282 individual cases of measles were confirmed in 31 states. This is the greatest number of cases reported in the U.S. since 1992. Of the 1,282 cases, 128 of the people who got measles were hospitalized, and 61 reported having complications, including pneumonia and encephalitis. Brazil
The spread of measles had been interrupted in Brazil in 2016, with the last known case twelve months earlier.