In most humanitarian crises since early 90s the top 5 killers are: • Diarrhoeal diseases (water & VBD borne) • Malaria (VBD) • Measles • Pneumonia • Malnutrition But other parasitic and viral disease may predominate in certain regions
The nature of vectors Group discussion activity: • In small groups, brainstorm types of vectors, and areas of overlap with other sectors (5 minutes) • Discuss in plenary (5 minutes)
Disease vectors and their control in emergencies A disease vector: a carrier/transmitter of disease from person to person A pest or ‘nuisance’ vector: similar, but do not transmit disease
Transmission Cycles of Parasitic, Viral & Bacterial VBDs • Many parasites have a single host • Vectors • Arthropods (i.e.) • Mechanical vector (flies) = bacterial dysentery • Biological vector (mosquito) = malaria & dengue • Molluscs (i.e.) - Host vectors (snails) = schistosomiasis • Hosts • Definite host (in which sexual reproduction occurs) • Intermediate host (larval or asexual stages occur) • Note: many protozoa are asexual (Leishmania)
Vectors – their importance The control of vectors is particularly important in emergencies because: • Regular control measures may break down • New breeding grounds may be created (eg floods) • Parasites can invade new/vulnerable communities • Lack of immunity if affected population moving into new areas • Poor sanitation & hygiene in new overcrowded settlements rapid spread of vectors
Sphere Handbook Guidelines on vectors • 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. • Vector control standard 2: physical, environmental and chemical protection measures. The numbers of disease vectors that pose a risk to people's health and nuisance vectors that pose a risk to people's well-being are kept to an acceptable level.
Common Vectors and their control Must identify vector and understand life cycle for effective control. • Regular assessment needed for immediate control • Distinguish – and prioritise - between disease risk and nuisance • Use environmental controls where possible • Only use chemical spraying as last resort, as • Frequent use causes resistance • Can be poisonous • Environmentally polluting