Fever – BioQuakes

Although fever was originally thought to be a reaction to infection, recent studies indicate that it has also played a role in immune defense since the earliest vertebrates. Recent research on Nile tilapia shows that fever-like behavior enhances adaptive immunity, challenging preconceived notions that this connection evolved later in warm-blooded animals. This finding deepens our understanding of immune system evolution and raises questions about how we deal with fevers today.

A study published in the Proceedings of the National Sciences examines how Nile tilapia (Oreochromis niloticus) use behavioral fever to fight off infections. In contrast to mammals, who generate fever internally, cold-blooded fish seek out warmer environments when sick. Scientists found that tilapia who were infected with Edwardsiella piscicda actively swam to water that was roughly 5°C warmer than normal. You may ask the outcome? Compared to fish kept at normal temperatures, these fish showed higher survival rates and had fewer bacteria in their livers.

The survival and effectiveness of T cells, which are essential elements of adaptive immunity, were improved by fever. Unlike in mammals, fever in the fish did not trigger an explosion of T cells, but rather increased their resistance to programmed cell death (apoptosis). After eight days, this effect went away, indicating that the immune system is carefully balanced to avoid over activation. The research offers strong evidence that the connection between fever and adaptive immunity first appeared in ancient vertebrates, long before they transitioned from water to land.

In AP Biology, innate and adaptive immunity are two primary parts of the immune system that we study. Fever plays a crucial role in both. The innate immune system reacts first with physical barriers and rapid inflammatory reactions, such as fever, which increases body temperature in order to make the body resistant to pathogens. In the adaptive immune system, T and B cells produce targeted reactions. Particularly, this study connects to our understanding if how fevers enhance T cell efficiency. According to this study, fever improves the survival and functionality of T cells, which require activation to effectively target and destroy pathogens. This also connects to what we have learned about cytokines, which are signaling molecules that help regulate fever and inflammation. Instead of only seeing fever as a symptom that should be repressed, understanding the physiological benefits of it can help us appreciate its role in immune regulation.

Many people instinctively take fever-reducing medications like Tylenol when they are sick, but this research suggests that fever plays an active protective role in helping overcome sickness. If fever helps T cells survive and fight infections more effectively, should we always try to suppress it and get rid of it? Share down below!

Recently an article was released summarizing the discovery of a new disease in Africa. In 2009 a fifteen year old boy in a small village in the Democratic Republic of the Congo fell ill. The initial symptoms were malaise and a bloody nose, but quickly the boy developed an acute hemorrhagic fever. Within two days of the showing symptoms the boy died. Approximately eleven days later a thirteen year old girl who went to the same school as Patient One developed similar symptoms, and died three days later. At the local health center which both Patients One and Two visited, a thirty-two year old male nurse began to experience identical symptoms. He was moved to the hospital in Boma, Democratic Republic of the Congo, where the doctors drew blood and began to test for known viruses; they found nothing. However, very recently a research team used deep sequencing to determine the pathogen,which they dubbed “Bas-Congo Virus”, and posted their results in the Public Library of Science Journal. It was discovered that the virus belonged to the Rhabdoviridae family, best known for the Rabies virus. Interestingly enough, though, the Bas-Congo virus only shares 34% of the amino acids found in other Rhabdoviruses, meaning that it is very different. The discovery of this virus may end up being of great importance due to the possibility that the virus may return. In any case, we will have one less pathogen on this planet to identity lest there be another, more deadly, outbreak.

BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Fever

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