'IRAQ AND THE PERSIAN GULF' [‎269v] (541/862)

PUBLIC HEALTH AND DISEASE
4 H
floods of the rivers in the plains and abnormal rains in the hills. The
flood season caused by melting snow in the hills is from March to
May or June (figs. 3, 4). The rainy season is from November to
March (p. 175); if excessive, numerous stagnant pools are left in the
beds of rivers and of streams in the hills.
Of the anopheline mos<^mX.ozs, Anophelespulcherrimus is the charac
teristic and dominant species in the Shatt al Arab region, in the lower
Tigris and Euphrates deltas, and in the central plain of Iraq. It is an
Asiatic species and has not been reported west of the Syrian desert.
Its power of flight and resistance to desiccation explain its dominance
over other species in the alluvial desert. It breeds in a variety of
situations, but the most favourable conditions are found in swamps.
Fortunately it is not a very effective vector of malaria, and where no
other carrier is present, as in the central plain of Iraq, malaria
is generally of low endemicity. This species becomes less common
northwards, as swamps diminish in number and extent.
Anopheles stephensii is also found in the Shatt al Arab region and in
the lower Tigris and Euphrates deltas. It has been reported as far
north-west as Karbala; on the Tigris it is rarely found north of Amara.
Nowhere in Iraq is it found in such large numbers as is A. pulcher-
rimus, but it is a much more effective vector of malaria, and is respon
sible for most of the malaria of southern Iraq. It breeds in excavated
ground and also in partly blocked irrigation channels and in casual
water. This species is an active carrier of malaria in Bombay, where
it breeds in wells.
Anopheles superpictus is the most important vector of malaria in
northern Iraq; it has not been reported south of Baghdad. Its natural
breeding-places are the pools in the beds of streams and rivers, but
larvae are sometimes found in flowing water and in irrigation channels.
The species has been found breeding at altitudes of 5,000 feet. It has
a wide distribution and is an important transmitter of malaria in
Macedonia and other Mediterranean countries; it also occurs in the
extreme north of India.
Anopheles maculipennis, the predominant anopheline of Europe,
occurs also in northern Iraq where its distribution is similar to that of
A. superpictus, though it does not appear to be an important vector of
malaria.
Other species of Anopheles have been found in Iraq, but none seems
to be important in the transmission of malaria.
In 1939 there were 490,319 cases of malaria treated in the medical
institutions of Iraq—14 per cent, of all patients treated. The percent