History of Vaccines Blog
Measles Circulates in Venezuela Again
Ongoing economic and civic unrest led to a return of measles to Venezuela in 2018. The World Health Organization had declared the entire Region of the Americas free from circulating measles in 2016, only to have the highly infectious disease return at a time of crisis.
Thomas Francis Jr MD
Thomas Francis, Jr, MD (1900-1969), was an American physician and researcher. In 1940, he isolated influenza virus type B for the first time while working at Rockefeller University in New York City. Later, he organized the 1954 Salk poliovirus vaccine clinical trial while working at the University of Michigan.
Influenza: New Type of Influenza Isolated
Researchers had observed that the blood of some influenza patients did not react with antibodies to the influenza virus that an English team had isolated in 1933. Many therefore suspected that different types of influenza viruses existed.
Influenza: Influenza Virus Isolated
British scientists Wilson Smith, MD, C.H. Andrewes, MD, and P.P. Laidlaw isolated influenza virus.
Widespread influenza in early 1933 gave these scientists the chance to demonstrate the cause of the disease. They took throat washings from patients with influenza symptoms and filtered them through a material that bacteria could not pass through. They tested the washings for the presence of bacteria by trying to culture them on a variety of media. The washings proved not to contain any detectable bacteria. Then they tried to infect a variety of animals with the throat washings.
Borrelia burgdorferi bacteria
This digitally-colorized scanning electron micrograph shows Borrelia burgdorferi bacteria derived from a pure culture. Borrelia burgdorferi, the cause of Lyme disease, is transmitted to humans via the bite of an infected tick.
Measles Rash in Child
This illustration from a 19th century French medical text depicts the characteristic measles rash.
Original image in Rayer, Pierre François Olive, 1793-1867. Traité théorique et pratique des maladies de la peau(Paris : Chez J. B. Bailliere, 1835). ZJa 8a (Historical Medical Library of the College of Physicians of Philadelphia)
Microcephaly in Infant
Zika virus infection during pregnancy can lead to a variety of harmful outcomes for the pregnancy and baby. Microcephaly is a birth defect of the brain that may result. Children with microcephaly have small head sizes and brains and may have intellectual disability, sight and hearing problems, and problems with motor skills.
Zika Virus Emergency Ends
The WHO declared an end to the Zika virus public health emergency of international concern. Effective mosquito control measures and an increasing population of humans previously infected with Zika virus led to a slowing of new cases. However, by the end of the epidemic, more nearly 600,000 cases of Zika virus infection were suspected to have occurred in the Americas, and nearly 4,000 babies were confirmed to have congenital syndrome associated with Zika virus infection.
WHO Declares Zika Virus Emergency
The World Health Organization announced that the spread of Zika virus was a public health emergency of international concern. At the time, the WHO's Emergency Committee had sufficient information to announce that a strong association existed between Zika virus infection in pregnant women and microcephaly and other birth defects in their infants. Over the next months, this evidence, and evidence that Zika virus infection could lead to Guillain Barre Syndrome, would grow more convincing.
Map of Yemen
A cholera epidemic began in Yemen in April 2017, raging through a country whose water, sanitation, and health infrastructures had been damaged by conflict. As of mid-August, about 500,000 cases and nearly 2,000 deaths had occurred.