'IRAQ AND THE PERSIAN GULF' [‎272v] (547/862)

420 PUBLIC HEALTH AND DISEASE
four-fifths of all cases have occurred from March to June inclusive,
with half of these in May.
Plague is a disease of rats: infection is conveyed from rat to rat, and
from rat to man by the rat flea. The incidence of human cases is in
certain circumstances a very inadequate index of the amount of rat
plague. The closeness of the association of rats with man, the species
of rat, and the species of flea are all factors influencing the adequacy
of this index. There are large numbers of rats in Baghdad, as in most
oriental cities, so that energetic measures for their destruction have
been adopted. Nine out of ten of those destroyed were black house-
rats (Rattus rattus) which are more closely associated with man in
oriental conditions than any other species. The other species was the
larger shorter-tailed brown rat (Rattus decumanus) which frequents
drains, basements, and outhouses rather than the human dwelling.
Much the most prevalent rat flea is Xenopsylla cheopis, the most
efficient transmitter of plague infection.
When plague has threatened, recourse has been had to anti-plague
inoculation, sometimes on a very large scale. In 1926 more than
141,000 inoculations were performed in Baghdad city. No anti
plague inoculation was necessary in 1939.
Small-pox
This disease appears to be endemic throughout Iraq, but effective
vaccination has prevented its being a very serious cause of morbidity
or death. Vaccination was made compulsory by the Vaccination Law
in 1922 for all infants, for all pupils and students in private or state
schools, for all immigrants and refugees, for employees of factories and
workshops, and for domestic servants. The numbers of cases and deaths
attributed to small-pox during four recent years were: 1936, 198 and
45; 1937, 28 and 2; 1938, 39 and 10; 1939, in and 19. In 1939 the
provinces affected were Sulaimaniya (88), Kirkuk (12), Amara (9),
and Diwaniya (2). The number of vaccinations performed in 1939
was 275,649. The vaccine is manufactured in the Vaccine Lymph
Institute of Baghdad.
Typhus Fever
A few typhus cases are reported each year, but no large-scale
epidemics have occurred in recent years. There were 207 in 1934
(158 in Kirkuk province); 76 in 1935 (all but 1 in Sulaimaniya
province); 2 in 1936; 44 in 1937 (28 in Kirkuk province); 4 in 1938;
45 in 1939 (23 in Baghdad province). Infection has been frequently