Immune system diseases protect against diseases

Measles: procreation while epidemic strengthens immune system

04/23/2014

Diseases such as tuberculosis, malaria and measles kill millions of people every year. Researchers now found that children who were conceived while an infectious disease was ravaging their parents provided a special protective mechanism. But with this improved immune system, there are also several disadvantages.

Parents give their child more effective defense against disease
Children conceived during epidemics may, under certain circumstances, have better chances of survival in later epidemics than their siblings, conceived of sooner or later. This report Rostock and London researchers in the journal „PLOS ONE“. Parents therefore give their child a more effective defense against diseases when a serious infectious disease is rife during conception. The study, which included scientists from the Max Planck Institute for Demographic Research (MPIDR) in Rostock, is based on historical data from the first half of the 18th century.

During measles epidemic, children conceived died less frequently from smallpox
The researchers compared life data from a total of 7,947 children from 575 families in the Canadian province of Quebec. The researchers used the information on births and deaths from copies of old church books. Kai Willführ from the MPIDR explained: „The entire population there lived relatively safely during the study period. At least there were no major wars and famines.“ The influence of epidemics on the mortality of humans can be easily understood. The scientists found that children conceived during a measles epidemic (1714-1715) survived a renewed epidemic (1729-1735) more frequently than their soon-to-be conceived siblings. According to this, their risk of dying of smallpox between 1729 and 1735 was about seven times lower. It was only the time of conception and not birth that mattered.

Stronger immune system at the expense of other developmental processes
A total of about six percent of all children died between 1729 and 1735. The scientists assume that the stronger defense against the children not only against the rampant during their conception measles, but also against other diseases. Nevertheless, it was not only beneficial for the children to have been conceived during the measles epidemic. Thus, they were much more unstable before the epidemic beginning in 1729 and died three times as often as their siblings, who had been born and conceived before the measles epidemic beginning in 1714. Her stronger immune system may have been at the expense of other developmental processes. According to the researchers, this leads to a higher mortality in phases with less pathogen and disease burden.

Temporal restriction of the alteration of the genetic material
There were hardly any differences between the siblings after 1735. „The effect is then no longer measurable. In adulthood, the time of conception seems to play no role“, so will. According to the Rostock researchers, there are many indications that the genetic material of the parents was changed for a limited time during the measles epidemic. Among other things could have been modified by the pathogen load Immungene in the sperm or the egg. If a woman became pregnant during this time, the parents gave their offspring their epidemic experience, so to speak. Willführ explained: „To put it bluntly, the child was told, Look, out here the environment is full of pathogens. Maybe it's better to invest more in your immune system than in growth.“ Then a child survives a disease rather than siblings who were conceived in disease-free times. Although the results of the study make a significant contribution to the understanding of the intergenerational development of the immune system, it remains unclear how the information on the pathogen load at the time of conception is passed on. (Sb)