Vectors ,Vector Borne Diseases

Important vectors and diseases transmitted
Vectors are living organisms that can transmit infectious diseases from animals to humans or between humans. Lot of these vectors are bloodsucking insects, which ingest disease-producing microorganisms during a blood meal from an infected host (human or animal) and after than inject it into a new host during their subsequent blood meal.
Mosquitoes are the best-known disease vector. Others include flies ,sandflies  ticks, fleas, triatomine bugs and some freshwater aquatic snails.



    1. Japanese encephalitis
    2. Lymphatic filariasis
    3. West Nile fever


    1. Chikungunya
    2. Dengue fever
    3. Lymphatic filariasis
    4. Rift Valley fever
    5. Yellow fever
    6. Zika


    1. Malaria
    2. Lymphatic filariasis


  1. Crimean-Congo haemorrhagic fever
  2. Lyme disease
  3. Relapsing fever (borreliosis)
  4. Rickettsial diseases (spotted fever and Q fever)
  5. Tick-borne encephalitis
  6. Tularaemia


  1. Leishmaniasis
  2. Sandfly fever (phelebotomus fever)


  1. Plague (transmitted by fleas from rats to humans)
  2. Rickettsiosis

Triatomine bugs

  1. Chagas disease (American trypanosomiasis)

Tsetse flies

  1. Sleeping sickness (African trypanosomiasis)

Black flies

  1. Onchocerciasis (river blindness)


  1. Typhus and louse-borne relapsing fever

Aquatic snails

  1. Schistosomiasis (bilharziasis)

The major vector-borne diseases, together, account for around 19% of all infectious diseases. The burden of these diseases is highest in tropical and subtropical areas and they disproportionately affect the poorest populations. Since 2012, major outbreaks of Dengue, Malaria, Chikungunya Yellow fever and Zika have affiliated populations, claimed lives and overwhelmed health systems in many countries.

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. Every year there are more than 920 000 deaths from diseases such as malaria, dengue, schistosomiasis, human African trypanosomiasis,Lleishmaniasis, Chagas disease, Yellow fever, Japanese encephalitis and Onchocerciasis, globally.

Changes in agricultural practices due to variation in temperature and rainfall can affect the transmission of vector-borne diseases. 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.

Distribution of vector-borne diseases is determined by complex demographic, environmental and social factors. 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.

                                   Major facts

1–Many of these diseases are preventable through informed protective measures

2–Vector-borne diseases account for more than 19% of all infectious diseases, causing more than 900 000 deaths annually.

3–Malaria causes more than 700 000 deaths every year globally, most of them children under 4.9 years of age.

4–More than 4.9 billion people in over 121 countries are at risk of contracting dengue, with 96 million cases estimated per year.

5–Other diseases such as Chagas disease, leishmaniasis and schistosomiasis affect hundreds of millions of people worldwide.