'IRAQ AND THE PERSIAN GULF' [‎269r] (540/862)

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PUBLIC HEALTH AND DISEASE
413
Malaria
Malaria is endemic throughout Iraq, but there are marked differ
ences in the degree of endemicity in different parts of the country.
Before the British invasion of Iraq in 1914 little or nothing was known
of the amount of malaria prevailing there. During the subsequent
years a comprehensive malaria survey was made by Christophers and
Shortt. 1 They showed that the physical divisions of the country—the
alluvial plain of the Tigris and Euphrates, the western and southern
deserts, and the Assyrian plains and foothills—each had its own set of
malarial conditions. Throughout the plains in summer there is so
continuous and intense a desiccation that conditions would be incom
patible with malaria, unless water were brought on to the land from
perennial rivers. The breeding-places of Anopheles mosquitoes are
peculiarly dependent upon irrigation. High-level canal irrigation is
not inherently dangerous, because none of the local species of
Anopheles breeds in canal distributaries. But flooding and leaks
caused by faulty construction or neglect provide mosquito breeding-
places, as does the lack of drainage and waterlogging caused by care
less cultivators. It is these which may result in high malaria endemi
city. Where there are no high-level canals and where the river is
below the level of the surrounding country, lift-irrigation (p. 440) is
practised over limited strips of land along the river-banks. Water
raised in this way is too valuable to waste and does not lead to much
mosquito breeding. This is possibly one reason why there is little
malaria in Baghdad city. Lower down the delta the level of the
river in the flood-season is above that of the surrounding country.
The channels leading water to the land are often carelessly made and
much water runs to waste. Low-lying or excavated land is turned into
swamp and much breeding of Anopheles results. The date-groves
along the Shatt al Arab have a special form of tidal irrigation (p. 440).
When the flood-levels in the river are very high the water in the
ditches may overflow and convert depressed or excavated areas into
swamps. At low river-levels portions of the channels may become
stagnant. In both of these ways mosquitoes find favourable breeding-
places.
In the Assyrian plains and the foothills, pools in river-beds and
especially in small non-perennial tributaries are responsible for
prolific breeding of Anopheles.
Serious outbreaks of malaria in Iraq are associated with abnormal
1 See Bibliography, Appendix F.