Insect Vectors Involving in Mechanical Transmission of Human Pathogens for Serious Diseases

Despite efforts of modern medicine, spread of arthropod-borne diseases is still one of the most serious concerns facing by public health officials and medical community in general. Health medical entomologists work in the public health arena, dealing with insects and other arthropods that parasitize, bite, sting and are vectors that transmit diseases to humans. Some important insects that parasitize humans are lice, fleas, bedbugs, ticks and scabies mites, while biting insects include mosquitoes, midges, sand flies, black flies, horse flies and stable flies, all of which may be vectors of pathogens. This article discusses mechanical transmission of pathogenic microbes by insect vectors, explores the different ways humans get infected and discusses the control measures against vectors. Majority of disease-causing organisms are arthropods (85%), among which insects and arachnids are of great medical importance. Insects spread diseases primarily via stings, bites, infestation of tissues and indirect transmission of pathogens. Vectors such as house fly, eye gnats, ants and cockroaches spread diseases by literally carrying pathogens on the surface of their bodies from place to place. Medically most important vectors are the common house fly (Musca domestica) and the greater house fly (Muscina stabulans), both having a more or less worldwide distribution. House flies can be vectors of helminths, faecal bacteria, protozoans and viruses, leading to the spread of enteric diseases (dysenteries and typhoids). Cockroaches specifically Blattella germanica and Periplaneta americana carry disease-causing organisms, typically those causing gastroenteritis. They carry disease-causing organisms on the legs and bodies and deposit on food as they forage. Excrement and cast skins of roaches also contain a number of allergens. Losses caused by arthropod-borne diseases include not only the direct costs of medicine and health care, but also indirect costs resulting from stress, absenteeism and reduced productivity. Maintenance of good hygiene, vector control and vaccination are very important to prevent the spread of these infectious diseases. Vector borne diseases, most of which are transmitted in and around the homes, are best controlled by a combination of vector control practices, medicines and vaccines. The process of bringing vector control into the mainstream strategy for future eradication emphasizes that new strategies for prevention and control of vector-borne diseases should be conducted through integrated vector management plan.