Genital herpes is one of the most common STDs in the Netherlands. Who was the first patient to pass this sexually transmitted disease to our ancestors? British scientists think they have found the answer. They assign the humanoid Paranthropus boisei as guilty.
When and how the first human ancestor contracted genital herpes? The research of Charlotte Houldcroft and colleagues from Cambridge and Oxford Brookes University show this. They base their conclusions in the journal Virus Evolution on fossil finds that show when and where which hominins lived in Africa, the habitat of the ancestors of chimpanzees and genetic calculations that map the evolutionary history of the virus.
Vesicles on mucous membranes
There are two types of herpes simplex viruses that can infect humans:HSV1 and 2. Both viruses can cause genital herpes, but HSV2 does so in eighty percent of cases. HSV1 is more often the cause of blisters on another part of the body:the cold sore.
Our ancestors probably carried HSV1 since they split from the chimpanzee ancestors about seven million years ago. For millions of years, they escaped infection with HSV2. Infection with HSV1 probably protected against infection with HSV2, which was still present in the mouth at the time. Only when HSV2 ended up on other mucous membranes – those of the genitals – did it have a chance of survival.
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The culprit
By the time modern humans left Africa 100,000 years ago, they were probably infected with HSV2, otherwise the global spread is difficult to explain. Previous genetic analyzes showed that HSV2 was much more similar to the variant of the virus that chimpanzees carry:ChHV1. That same study showed that the human line became infected sometime between 3 and 1.4 million years ago. The researchers now believe that a hominin, which was infected by a chimp ancestor, had contact with a human ancestor.
And they point out the humanoid P. forest egg as guilty. Houdlcroft and colleagues believe that a copy of P. forest egg ate infected chimpanzee meat while he himself had open wounds. That's how he got infected. At the time, the populations were small and one infected specimen could easily spread to the rest of the group.
Gorilla pubic louse
P. forest egg shared its habitat with our ancestor Homo erectus, which arose two million years ago. Lake Turkana there is such an area in Kenya. Gay erectus hunted several animals, and according to the researchers it is not inconceivable that he caught an infected P. forest egg has eaten. After that first infection, HSV2 moved from the mouth to the genitals through touch.
And because of that confluence of circumstances, we are still stuck with that miserable pathogen today. Once infected, there is no cure, you continue to carry the virus. And it also spreads easily through bodily fluids. However, the blisters can be treated well with medication.
With their method, the researchers also hope to be able to find out how we got pubic lice from the gorilla ancestors 3.3 million years ago and how the human papilloma virus from the Neanderthals ended up here.