Vectors
Vectors are living organisms that can transmit infectious pathogens 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 transmit it into a new host, after the pathogen has replicated. Often, once a vector becomes infectious, they are capable of transmitting the pathogen for the rest of their life during each subsequent bite/blood meal.
Vector-borne diseases
Vector-borne diseases are human illnesses caused by parasites, viruses and bacteria that are transmitted by vectors. 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.
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 in many countries. Other diseases such as Chikungunya, leishmaniasis and lymphatic filariasis cause chronic suffering, life-long morbidity, disability and occasional stigmatisation.
Distribution of vector-borne diseases is determined by a complex set of demographic, environmental and social factors. Global travel and trade, unplanned urbanization, and en
List of vector-borne diseases, according to their vector
The following table is a non-exhaustive list of vector-borne disease, ordered according to the vector by which it is transmitted. The list also illustrates the type of pathogen that causes the disease in humans.
Vector | Disease
caused | Type
of pathogen | |
Mosquito | Aedes
| Chikungunya Dengue Lymphatic filariasis Rift Valley fever Yellow Fever Zika | Virus Virus Parasite Virus Virus Virus |
Anopheles | Lymphatic filariasis Malaria | Parasite Parasite | |
Culex | Japanese encephalitis Lymphatic filariasis West Nile fever | Virus Parasite Virus | |
Aquatic snails | Schistosomiasis (bilharziasis)
| Parasite | |
Blackflies | Onchocerciasis
(river blindness)
| Parasite | |
Fleas | Plague (transmitted from rats to humans) Tungiasis
| Bacteria Ectoparasite
| |
Lice | Typhus Louse-borne relapsing fever | Bacteria Bacteria | |
Sandflies | Leishmaniasis Sandfly
fever (phlebotomus fever)
| Parasite Virus | |
Ticks | Crimean-Congo haemorrhagic fever
Lyme disease Relapsing fever (borreliosis) Rickettsial
diseases (eg: spotted fever and Q fever)
Tick-borne encephalitis Tularaemia
| Virus Bacteria Bacteria Bacteria Virus Bacteria | |
Triatome bugs | Chagas disease (American trypanosomiasis) | Parasite | |
Tsetse flies | Sleeping sickness (African trypanosomiasis) | Parasite | |
WHO response
The "Global Vector Control Response (GVCR) 2017–2030" was approved by the World Health Assembly in 2017. It provides strategic guidance to countries and development partners for urgent strengthening of vector control as a fundamental approach to preventing disease and responding to outbreaks. To achieve this a re-alignment of vector control programmes is required, supported by increased technical capacity, improved infrastructure, strengthened monitoring and surveillance systems, and greater community mobilization. Ultimately, this will support implementation of a comprehensive approach to vector control that will enable the achievement of disease-specific national and global goals and contribute to achievement of the Sustainable Development Goals and Universal Health Coverage.
WHO Secretariat provides strategic, normative and technical guidance to countries and development partners for strengthening vector control as a fundamental approach based on GVCR to preventing disease and responding to outbreaks. Specifically WHO responds to vector-borne diseases by:
- providing evidence-based guidance for controlling vectors and protecting people against infection;
- providing technical support to countries so that they can effectively manage cases and outbreaks;
- supporting countries to improve their reporting systems and capture the true burden of the disease;
- providing training (capacity building) on clinical management, diagnosis and vector control with support from some of its collaborating centres; and
- supporting the development and evaluation of new tools, technologies and approaches for vector-borne diseases, including vector control and disease management technologies.
A crucial element in reducing the burden of vector-borne diseases is behavioural change. WHO works with partners to provide education and improve public awareness, so that people know how to protect themselves and their communities from mosquitoes, ticks, bugs, flies and other vectors.
Access to water and sanitation is a very important factor in disease control and elimination. WHO works together with many different government sectors to improve water storage, sanitation, thereby helping to control these diseases at the community level.