World Mosquito Day: Know about different vectors and diseases they spread

World Mosquito Day commemorates Sir Ronald Ross’ 1897 discovery of the link between mosquitoes and malaria transmission. The event raises awareness about the threat of malaria and other diseases transmitted by the world’s deadliest animal

Image source: Google
Image source: Google

Mosquitoes are one of the deadliest animals in the world. Their ability to carry and spread diseases to humans causes millions of deaths every year.

There are several different mosquitoes that can carry many different diseases. Aedes, Anopheles, Culex mosquitoes act as vectors (living organisms that can transmit infectious diseases between humans or from animals to humans) for several diseases.

Vector-borne diseases are human illnesses caused by parasites, viruses and bacteria that are transmitted by mosquitoes, sandflies, triatomine bugs, blackflies, ticks, tsetse flies, mites, snails and lice.

Main vectors and diseases they transmit

Vectors are living organisms that can transmit infectious diseases between humans or from animals to humans. Many of these vectors are bloodsucking insects, which ingest disease-producing microorganisms during a blood meal from an infected host (human or animal) and later inject it into a new host during their subsequent blood meal.

Mosquitoes are the best-known disease vector. Others include ticks, flies, sandflies, fleas, triatomine bugs and some freshwater aquatic snails.

Aedes

Anopheles

Culex

Sandflies

Ticks

  • Crimean-Congo haemorrhagic fever
  • Lyme disease
  • Relapsing fever (borreliosis)
  • Rickettsial diseases (spotted fever and Q fever)
  • Tick-borne encephalitis
  • Tularaemia

According to WHO, the major vector-borne diseases, together, account for around 17% of all infectious diseases. The burden of these diseases is highest in tropical and subtropical areas and they disproportionately affect the poorest populations.

Since 2014, major outbreaks of dengue, malaria, chikungunya yellow fever and Zika have afflicted populations, claimed lives and overwhelmed health systems.

Dr Abhijit Lodha, a physician from Pune stated, “Distribution of vector-borne diseases is determined by complex demographic, environmental and social factors.”

He added, “Global travel and trade, unplanned urbanization and environmental challenges such as climate change can impact on pathogen transmission, making transmission season longer or more intense or causing diseases to emerge in countries where they were previously unknown.”

Mosquito-borne diseases remain a real health threat worldwide and are in fact, the Grim Reaper incarnate. Every year there are more than 700,000 deaths from diseases such as malaria, dengue, schistosomiasis, human African trypanosomiasis, leishmaniasis, Chagas disease, yellow fever, Japanese encephalitis and onchocerciasis, globally.

Dr Anjali Sabane, a health official from PMC, said, “Changes in agricultural practices due to variation in temperature and rainfall can affect the transmission of vector-borne diseases.”

Dr Sabane informed, “The growth of urban slums, lacking reliable piped water or adequate solid waste management, can render large populations in towns and cities at risk of viral diseases spread by mosquitoes. Together, such factors influence the reach of vector populations and the transmission patterns of disease-causing pathogens.”