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4. Vector Control
A vector is a disease-carrying agent and vector-borne diseases are a major cause of sickness and death in many disaster situations. Mosquitoes are the vector responsible for malaria transmission, which is one of the leading causes of morbidity and mortality. Mosquitoes also transmit other diseases, such as yellow fever and dengue haemorrhagic fever. Non-biting or synanthropic flies, such as the house fly, the blow fly and the flesh fly, play an important role in the transmission of diarrhoeal disease. Biting flies, bed bugs and fleas are a painful nuisance and in some cases transmit significant diseases such as murine typhus and plague. Ticks transmit relapsing fever and human body lice transmit typhus and relapsing fever. Rats and mice can transmit diseases such as leptospirosis; and a specific species of rat is responsible for transmission of Lassa fever.These rodents can also be hosts for other vectors e.g. fleas, which may transmit plague and murine typhus.
Vector-borne diseases can be controlled through a variety of initiatives, including appropriate site selection and shelter provision, appropriate water supply, excreta disposal, solid waste management and drainage, the provision of health services (including community mobilisation and health promotion), the use of chemical controls, family and individual protection and the effective protection of food stores. Although the nature of vector-borne disease is often complex and addressing vector-related problems may demand specialist attention, there is much that can be done to help prevent the spread of such diseases with simple and effective measures, once the disease, its vector and their interaction with the population have been identified.
Vector control standard 1: individual and family protection
All disaster-affected people have the knowledge and the means to protect themselves from disease and nuisance vectors that are likely to represent a significant risk to health or well-being. |
Key indicators (to be read in conjunction with the guidance notes)
- All populations at risk from vector-borne disease understand the modes of transmission and possible methods of prevention (see guidance notes 1-5).
- All populations have access to shelters that do not harbour or encourage the growth of vector populations and are protected by appropriate vector control measures.
- People avoid exposure to mosquitoes during peak biting times by using all non-harmful means available to them. Special attention is paid to protection of high-risk groups such as pregnant and feeding mothers, babies, infants, older people and the sick (see guidance note 3).
- People with treated mosquito nets use them effectively (see guidance note 3).
- Control of human body lice is carried out where louse-borne typhus or relapsing fever is a threat (see guidance note 4).
- Bedding and clothing are aired and washed regularly (see guidance note 4).
- Food is protected at all times from contamination by vectors such as flies, insects and rodents.
Guidance notes
1. Defining vector-borne disease risk: decisions about vector control interventions should be based on an assessment of potential disease risk, as well as on clinical evidence of a vector-borne disease problem. Factors influencing this risk include:
- immunity status of the population, including previous exposure, nutritional stress and other stresses. Movement of people (e.g. refugees, IDPs) from a non-endemic to an endemic area is a common cause of epidemics;
- pathogen type and prevalence, in both vectors and humans;
- vector species, behaviours and ecology;
- vector numbers (season, breeding sites, etc.);
- increased exposure to vectors: proximity, settlement pattern, shelter type, existing individual protection and avoidance measures.
2. Indicators for vector control programmes: commonly used indicators for measuring the impact of vector control activities are vector-borne disease incidence rates (from epidemiological data, community-based data and proxy indicators, depending on the response) and parasite counts (using rapid diagnostic kits or microscopy).
3. Individual malaria protection measures: if there is a significant risk of malaria, the systematic and timely provision of protection measures, such as insecticide-treated materials, i.e. tents, curtains and bednets, is recommended. Impregnated bednets have the added advantage of giving some protection against body and head lice, fleas, ticks, cockroaches and bedbugs. Long-sleeved clothing, household fumigants, coils, aerosol sprays and repellents are other protection methods that can be used against mosquitoes. It is vital to ensure that users understand the importance of protection and how to use the tools correctly so that the protection measures are effective. Where resources are scarce, they should be directed at individuals and groups most at risk, such as children under five years old, non-immunes and pregnant women.
4. Individual protection measures for other vectors: good personal hygiene and regular washing of clothes and bedding is the most effective protection against body lice. Infestations can be controlled by personal treatment (powdering), mass laundering or delousing campaigns and by treatment protocols as newly displaced people arrive in a settlement. A clean household environment, together with good waste disposal and good food storage, will deter rats and other rodents from entering houses or shelters.
5. Water-borne diseases: people should be informed of health risks and should avoid entering water bodies where there is a known risk of contracting diseases such as schistosomiasis, Guinea worm or leptospirosis (transmitted by exposure to mammalian urine, especially that of rats: see Appendix 4). Agencies may need to work with the community to find alternative sources of water or ensure that water for all uses is appropriately treated.
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