Transmission
A mosquito's period of feeding is often undetected; the bite only becomes apparent because of the immune reaction it provokes. When a mosquito bites a human, she injects saliva and anti-coagulants. For any given individual, with the initial bite there is no reaction but with subsequent bites the body's immune system develops antibodies and a bite becomes inflamed and itchy within 24 hours. This is the usual reaction in young children. With more bites, the sensitivity of the human immune system increases, and an itchy red hive appears in minutes where the immune response has broken capillary blood vessels and fluid has collected under the skin. This type of reaction is common in older children and adults. Some adults can become desensitized to mosquitoes and have little or no reaction to their bites, while others can become hyper-sensitive with bites causing blistering, bruising, and large inflammatory reactions, a response known as Skeeter Syndrome.
Read more about this topic: Mosquito-borne Disease