Disease vector

In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen such as a parasite or microbe, to another living organism. Many familiar vectors, such as mosquitos, ticks, and certain flies rely on blood-feeding and can acquire or pass on pathogens during that process. Disease vectors remain a major global health challenge. The World Health Organization reports that these illnesses make up over 17% of all infectious diseases worldwide, and are responsible for hundreds of thousands of deaths every year.

Agents regarded as vectors are mostly blood-sucking (hematophagous) arthropods such as mosquitoes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected the stomach tissue of a mosquito. The process of proving that a vector is responsible for transmitting pathogens is called vector incrimination. Transmission depends on interactions among a host, a pathogen, and a vector species that is capable of carrying the infection. Some pathogens may multiply or undergo part of their life cycle inside of the vector, while others are transferred from one surface to another without developing inside the carrier.

Shifts in climate, expanding cities, and land-use changes are reshaping where vectors can survive. Warmer temperatures and altered rainfall patterns can boost mosquito and tick populations, which can extend their breeding seasons and geographic reach. Urban green spaces and infrastructure can create new breeding grounds for vectors such as mosquitos, thus bringing them closer to dense human populations. Additionally, international trade and human movement can rapidly transport vectors and pathogens across continents, which may introduce them to naive populations. Naive populations refer to a set of participants who have not previously encountered or been exposed to a particular substance, treatment, or condition, and therefore have no built-up immunity or prior experience with it.

Due to these shifting conditions, public health agencies are encouraging broad and coordinated approaches to reducing vector-borne diseases. Strategies implemented include monitoring vector populations, improving environmental management, increasing community participation, and adopting newer tools and technologies where appropriate.