Parasitology is the scientific study of parasites. Some parasitology studies evaluate the relationship between parasitic organisms and their hosts. Other studies look for and describe different types of parasites. Parasitology has applications in human and veterinary medicine. The study of parasites draws on other scientific disciplines, such as microbiology, organic chemistry, and cytology.
Although the name parasite has negative connotations, not all parasites negatively affect their hosts. In some cases, parasitology demonstrates how a parasite's relationship with its host is mutually beneficial, called mutualism . The parasite and the host can protect themselves from each other's presence or provide food. When the parasite and the host cannot exist separately, their relationship is called symbiotic . The two organisms depend equally and mutually on each other.
Parasitology, when used in human and veterinary drug applications, tends to examine the relationship between parasites that invade and cause damage to the animal or human body. For example, insects that are disease vectors are studied to see to what extent they transmit those diseases to humans or animals. The mosquito is a parasite that affects not only human populations, but also birds and horses. Some mosquitoes carry West Nile virus, which in severe cases can cause encephalitis and sometimes death. To improve the medical understanding of West Nile Virus, parasitologists must understand the mosquito.
From previous studies, parasitologists determined that not all mosquitoes are equally dangerous and not all carry West Nile virus. Only female mosquitoes bite, while male mosquitoes drink nectar. More recent parasitology studies have identified that mosquitoes carrying West Nile Virus have a tendency to survive and be present through the winter in moderate climates. So from this, we know that the presence of a mosquito in December in the US means an increased risk for us of contracting West Nile virus.
In veterinary medicine, parasitologists work specifically to eliminate flea infestation in cats and dogs. Recent technology has evolved to allow dogs or cats to take one pill a month or have a spot treatment on their back that delays the maturation of fleas, thus preventing bites or directly killing biting fleas. Some fleas can be disease vectors. Fleas on rats caused the Black Death of the Middle Ages. Enhanced flea protection can minimize health risks and reduce flea infestation, providing relief for both pets and their owners.
Parasitology also studies the unicellular organisms that can make us sick, which can be bacteria or fungi. Such studies depend on the ability to identify and describe cells, cytology either microbiology at the microscopic level. The description of these cells and their presence has led to better detection of certain bacterial and parasitic infections.
Parasitology must concentrate not only on identifying and describing harmful cells, but also on the evolution of methods to destroy them. From this information, drugs are developed to treat specific infections. The understanding of parasites led to an understanding of the role of antibiotics in treating bacterial infections, possibly one of the most important medical developments in history.