Human and animal diseases transmitted by arthropods cause almost immeasurable social and economic losses. Many studies have been done on the socioeconomic costs of one or another of this group of diseases in the tropics but similar information for the USA and Canada is scattered, incomplete and not easily found. Most of the studies which have been carried out in the USA or Canada, have concentrated on the costs of health-care and cost of work loss for the patients. However, the cost of vector and reservoir host control activities to deal with outbreaks of vector-borne diseases is also very substantial and must also be taken into account. Though poorly documented, the economic costs associated with vector- and rodent-borne diseases are growing in the USA and Canada. Some examples are given here.

Eastern equine encephalitis

A study was undertaken to ascertain the economic burden imposed on some residents of Massachusetts who had survived eastern equine encephalitis (EEE) infections in the late 1980s. Transiently affected persons mainly required assistance of direct medical services; the average total cost per case was US $21000. Those who suffered persistent sequelae remained at home and seemed likely to live a normal life span, but without gainful employment, and they represented costs that ranged as high as US $0.4 million but levelled off at US $0.1 million after 3 years. Hospital costs approached about US $0.3 million a patient.