Rinderpest, Measles and Medieval Emerging Infectious Diseases

Some diseases seem like they should have always been with us. It has long been thought that measles was one of those with a pedigree stretching back into the depths of Antiquity, as soon as people were living in a high enough concentration to maintain a virus that needs a constant supply of human hosts.   A recent study by Yuki Furuse, Akira Suzuki, and Hitoshi Oshitani shows us that this is not the case.

All circulating strains of measles (MeV) have a common ancestor from the early 20th century. This says a lot about the global spread and need for constant naive human hosts of measles. Furuse, Suzuki and Oshitani went in search of measles previous last common ancestor with its most closely related virus Rinderpest (RPV), a cattle virus. Rinderpest was once a catastrophic disease wiping out cattle herds and causing human famines. The economic and human costs were so great that countries around the world successfully united to drive it into extinction. In 2010, the United Nations officially declared Rinderpest extinct in global livestock herds. What does it say about our priorities that Rinderpest is extinct and measles outbreaks are still occurring in the US?  While measles cases are dropping globally it is far from gone. In 2009, about 400 children were dying per day from measles, according to the World Health Organization.

Furuse, Suzuki and Oshitani (2010) collected DNA sequences for the hemagglutinin (H) and nucleocapsid (N) genes of the measles virus (MeV), and rinderpest (RPV) with the sequence for peste des pestitis rumninants virus being used to define the divergence point. I’m not an expert in the molecular clock models used so I can’t critique that aspect. Their molecular clock setting predicted 1916 (H gene)/1921 (N gene) as the last common ancestor point for MeV, close to previous estimates, and 1171 (N gene) / 1074 (H gene) for the divergence point with Rinderpest (RPV). Furuse, Suzuki and Oshitani (2010) therefore place the emergence of the Measles virus to between the 11th and 12th century.

Bayesian estimates of divergence time for the N gene. ©2010 Furuse et al; licensee BioMed Central Ltd.

Measles evolved in a context where humans and cattle were closely associated. Models predict that the  measles virus requires a naive (non-immune) human population of 250,000-500,000. These conditions were possible since prehistory in the Middle East. According to Furuse, Suzuki and Oshitani, the earliest “measles-like syndrome” was described in the 9th century by Abu Becr, also called Rhazes, and identifiable measles epidemics began to be recorded in the 11th to 12th century. They note that the ancestral virus before the divergence probably could infect both humans and cattle, though its symptoms may have been significantly different. The modifications that finally made measles a human-only virus should have given it significant boost in virulence.  Measles is highly contagious with a Ro of 15 (meaning each  person with measles infects on average 15 others). Malnourished children are known to have fatality rates around 40% (Crawford, 2007)  If an early medieval emergence holds up, then measles would have been a primary emerging infectious disease between the two major plague pandemics (5th-8th century and 14th century onwards).

Furuse Y, Suzuki A, & Oshitani H (2010). Origin of measles virus: divergence from rinderpest virus between the 11th and 12th centuries. Virology journal, 7 PMID: 20202190

Crawford, DH. (2007) Deadly Companions: How Microbes Shaped Our History. Oxford University Press.

WHO factsheet on Measles

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2 thoughts on “Rinderpest, Measles and Medieval Emerging Infectious Diseases

  1. According to Furuse, Suzuki and Oshitani, the earliest “measles-like syndrome” was described in the 9th century by Abu Becr, also called Rhazes

    The Andalusi also known as “el moro Rasis”? If so it would be worth checking the transmission, we don’t have very much of his original writing at all, though a lot of later writers claimed to quote him.

    More scientifically, do you know of anywhere simple but authoritative where I might find an explanation of the divergence maths that’s used for calculating the age of DNA, as here? Occasionally this come up…

    1. I’m don’t know of a good site to explain the formulas used to calculate divergence. I suspect they may be using computer programs. Its not really the age of the DNA but how far back to the common ancestor. Setting the molecular clock is the big variable. You also need the raw data of how many changes there are between the samples being compared. Calculating time of divergence is different than looking at ethnicity (as in your link to Guy’s post).

      I believe the blue bar on the diagram is the error bar, ie how far that divergence point could slip. You have to look at these dates like radiocarbon dates. You get a number but the error bars for a 95% confidence level are quite wide. The 95% confidence margin for divergence of MeV and RPV is: N gene 1171 (range 678-1612) and H gene 1074 (range 437 -1576).

      I think the take home message is still a medieval origin rather than in pre-history. Also keep in mind that the common ancestor may have been able to infect both cattle and humans, but rinderpest is probably the original virus so it could have caused cattle epizootics before the split.

      Thanks for the questions Jon, this is stuff I should have added in the original post.

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