What are Vector-borne diseases? Here're symptoms, history in numbers

While Kerala is witnessing a third outbreak of the Nipah virus, Uttar Pradesh is in the grip of a mysterious dengue-like fever that has killed at least 100 people, mostly children, in the past few weeks.

Mumbai too is seeing a rise in dengue cases from last year: 129 in 2020 to 138 in the past eight months of 2021. When it comes to malaria, 3,338 cases were reported in the financial capital till August 29 this year. As fresh cases of dengue and malaria rise amidst the Covid-19 pandemic, here is a look at major mosquito-borne diseases in numbers.

What are Vector-borne diseases? Human illnesses caused by parasites, viruses and bacteria that are trans­mi­tted by vectors, according to the World Health Organization. These diseases account for more than 17 per cent of all infectious diseases, causing over seven lakh deaths across the world annually.

Many of these vectors are bloodsucking insects, which take in disease-producing microorganisms during a blood meal from an infected host (human or animal) and later transmit it into a new host. When a vector becomes infectious, they are capable of transmitting the pathogen for the rest of their life during each subsequent bite/blood meal.

Mosquitos are only one type of vectors, who cause diseases such as Malaria, Dengue Chikungunya, etc. Other vector borne diseases are caused by vectors such as aquatic snails (Schistosomiasis), blackflies (river blindness), fleas (plague), lice (typhus), sandflies (Sandfly fever), ticks (Crimean-Congo haemorrhagic fever), Triatomine bugs (Chagas disease), and Tsetse flies (sleeping sickness).