Evolutionary Medicine


Humans and other species share many diseases. In fact, some diseases begin with animals. Zoonosis is the scientific name for when animals pass on diseases to humans. One of the first things people need to know is the difference between a vector and reservoir species. A vector species is any animal or microorganism that carries and transmits an infectious pathogen into another species. An example of a vector species is loa loa, which is a worm that can be found in the human eye. A reservoir species is the long-term host of a pathogen of an infectious disease. An example of a reservoir species is a raccoon that is carrying a parasite with a disease. Multiple cases have shown that humans are capable of contracting diseases from other animals. In order to develop cures for diseases, scientists need to understand their evolution. In my opinion, by studying the evolution of diseases in animals, scientists come up with more cures for them. Scientists have proven that humans are infected with malaria by mosquitos. Secondly, humans may also contract Lyme disease from ticks. Lastly, humans are capable of receiving HIV from chimps.

One disease humans have gotten from animals is malaria. Malaria is a serious and sometimes fatal disease caused by plasmodium, a parasite that carries the disease, that commonly infects a certain type of mosquito which feeds on humans (CDC, 2016).


The mosquito would be considered the vector and plasmodium would be a reservoir species. For example, when an Anopheles mosquito that has the malaria parasite bites a human the disease is transmitted into his or her blood. Malaria can neither be spread through casual contact or nor is sexually transmitted. It can only be transmitted via mosquito bites. Research has been done on a vaccine which targets a toxin the parasite releases. Scientists gave some mice the toxin GPI, and the mice who received the toxin were protected against many symptoms of malaria and did not die (AnimalResearch.info, not stated). By doing this experiment on mice, scientists can test the efficacy of a cure without harming any humans. In order for scientists to come up with a cure for malaria, scientists have to know how the disease has evolved over time. To do this a scientist would need to take a closer look at a mosquito who has had the parasite plasmodium for a long period of time then compare it to a mosquito that just received plasmodium. By looking at the two the scientist can determine whether or not a new cure needs to be made to destroy the disease.


A second disease that humans can get from animals is Lyme disease. Lyme disease is an inflammatory disease that causes a rash, headache, fever, and chills. Lyme disease was first found in Connecticut in 1975.  Most cases of Lyme disease are found in northeastern and upper mid-western states (CDC, 2016). Ticks pick up the disease by feeding on infected mice then the tick may pass on the disease to humans when biting them (CDC, 2016).


In 2008, scientists conducted an experiment on mice to see how the antibiotic ceftriaxone would affect the disease. After completing the antibiotic treatment, which took one month, the results showed that the disease could not be grown in the cells. However, bacteria were detected in the mice tissues. The implications of these findings from this experiment in humans are yet to be understood (NIH, 2014). By doing more research and furthering this experiment, the result could possibly lead to a cure for the disease in humans. One cure for Lyme disease exists today, but if the disease was to evolve, scientists would need to study one tick who recently received the disease and one who has been carrying the disease for a long period time. By doing this a scientist can look at the similarities or differences between the disease in the ticks to determine if a new cure will need to be made to cure the disease.

Lastly, a third disease that humans can get from animals is HIVs. HIV is a virus that can lead to immunodeficiency syndrome or AIDs if not treated (Lovgren, 2003). The origin of HIVs is still under investigation. Scientists believe humans got HIV from chimpanzees who have gotten the disease from either spot-nosed monkeys or red-capped mangabey. HIV was first


found in Central Africa in a chimp (for chimp’s HIV is called SIV). Scientists believe humans received HIV from chimpanzees by hunting them for meat, a couple hundred years ago, and came into contact with the infected blood (CDC, 2016). The HIV virus has been in the U.S. since at least the mid to late 1970s (CDC, 2016). Bone Marrow-Liver-Thymus mice is an example of an animal scientists use to make new treatments and vaccines for HIVs. Scientists transfer bone marrow, liver, and thymus tissue from humans, giving the mice a functionally human immune system. This allows them to be infected by HIV, so scientists can run tests on a cure for the disease. (AnimalResearch.info, not stated). As of now, HIV has no cure. Over the years, HIV has evolved to infect both humans and animals. Scientists must know how HIV is evolving over time to make a vaccine that will cure the disease for humans.

These cases show that humans are capable of receiving different types of diseases from animals. The cases also prove that human bodies are vulnerable to many different types of diseases. Animals can spread diseases to humans by humans coming into contact with the blood and by being bitten by animals that carry the disease. I believe this information is very important because knowing the evolution of diseases in humans and animals can help scientists make cures that are up to date with their adaptations.

Work Cited:

Centers for Disease Control and Prevention. 2016. Malaria. http://www.cdc.gov/Malaria/about/faqs.html

Centers for Disease Control and Prevention, 2016. Lyme Disease.


Centers for Disease Control and Prevention. 2016. HIV/AIDS.


National Geographic. 2003. HIV Originated With Monkeys, Not Chimps, Study Finds.


Washington State Department of Health. 2016. Lyme Disease.


AnimalResearch.info, not stated. Malaria.


AnimalResearch.info, not stated. AIDS & HIV.


National Institute of Allergy and Infectious Diseases, 2014. Lyme Disease Antibiotic Treatment Research.


Wikipedia, 2016. HIV.


Wikipedia, 2016. Lyme Disease.


Wikipedia, 2016. Malaria.


Marques, A.R. Curr Allergy Asthma Rep (2010)


Oxford, England., Malden, Mass., and Blackwell Science. 1996. Tropical Medicine & International Health