Medical Entomology a branch of entomology deals with arthropods that affect the health and well-being of man and vertebrate animals.Medical entomology is concerned with the impact of insects and related arthropods on the mental and physical health of humans, domestic animals, and wildlife. It is often subdivided into public health entomology and veterinary entomology. These divisions are tenuous since many of the same arthropods cause similar injuries and diseases in both humans and other animals.
Arthropods influence animal health in multiple ways. There are many arthropodal insects that affect human health.These arthropods include Diptera (Flies), Hemiptera (Bugs), Thysanoptera (Thrips), Phthiraptera (Louse), and Siphonaptera (Fleas).
They can parasitize, bite, sting, cause allergic reactions, and/or vector disease to humans. The most significant impact involves their role as primary vectors and alternate hosts of many devastating infectious disease agents. Parasitic agents transmitted by hematophagous arthropods include filariae, protozoa, bacteria, rickettsiae, and viruses. The listed arthropods may cause asthma or trigger allergies, contaminate food, irritate skin, cause direct injury, or carry agents causing diseases such as Lyme disease, epidemic typhus, trench fever, epidemic relapsing fever, malaria, encephalitis, yellow fever, dengue fever and many others.Arthropods also affect the health of vertebrates directly by triggering altered mental states (delusional parasitosis and entomophobia/arachnophobia), contact allergies, feeding annoyance and blood loss, envenomization, and myiasis.
Dengue viruses are a significant health risk globally. Severe cases of dengue often require hospitalization and can be life-threatening shortly after infection. Symptoms include a high fever, aches and pains, vomiting, and rashes. Warning signs of severe dengue infection include vomiting blood, bleeding from the gums or nose, and stomach tenderness/pain.
Zika, recently notorious, though rarely deadly, causes fever, joint pain, rashes and conjunctivitis. The most serious consequence appears when the infected person is a pregnant woman, since during pregnancy this virus can originate a birth defect called microcephaly.
St. Louis Encephalitis, a mosquito-borne disease that is characterized by fever and headaches upon initial onset of infection, arises from mosquitoes who feed on birds who are infected with the illness, and can result in death. The most common vector of this disease is Culex pipiens, also known as the common house mosquito.
Heartworm disease, a parasitic roundworm infection that affects dogs and other canids. Mosquitoes transmit larvae to the definitive host through bites. Adult heart worms infest the right heart and pulmonary artery, where they can cause serious complications including congestive heart failure.
Bacterial diseases
Bartonella bacilliformis, the causal agent of Carrion's disease, is transmitted by different members of the genus Lutzomyia. This disease is restricted to Andean areas of Peru and Ecuador, with historical reports in Southern Colombia.
Cockroaches carry disease-causing organisms (typically gastroenteritis) as they forage. Cockroach excrement and cast skins also contain a number of allergens causing responses such as, watery eyes, rashes, congestion of nasal passages and asthma.
Insect or Vector-borne diseases (VBDs) described above exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. As 40-60% people's residents in the world are not up to the standard that lead the best habitats of the arthropods. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished pathway. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of VBDs.
Without proper studying of morphology, physiology, ecology, biology and behavior of mentioned vectors, it is not possible to make correct and fruitful strategic plan to control vectors. Only the Medical Entomologists have the transparent ideas of the above criteria and mode of action of microorganisms transmitted by biting and blood sucking insects. So medical entomologists along with medical professionals are burning need to develop control measures of biting insects that can prevent humans from contracting some of those diseases. They have also developed ways to prevent the biting arthropods scientifically from biting humans.
The writer is a Professor and Head, Department of Entomology, National Institute of Preventive and Social Medicine, NIPSOM
