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A certain amount of variation occurs in the seasonal distribution
of the different species. On the lower gardens in the rains infection
with the malignant tertian parasite becomes prominent; but as the dry
weather advances this parasite tends to become less conspicuous and to-
wards the end of the dry and cold season quartan infections predominate.
Very often we have been struck with the existence of groups of
infections by one or other variety, a condition particularly noticeable in
the case of quartan forms.
Mixed infections are exceedingly common if not the rule; though
generally at the time of examination parasites of one or other species are
in the majority.
How MALARIA SHOWS ITSELF.
Malaria in a native population does not confine itself to causing
attacks of " fever ", and a due appreciation of its effects under such
circumstances is very necessary.
Child malaria.-Very young children are usually fat and healthy,
with normal blood free from parasites. They soon, however, begin
to get serious attacks of fever, and, at an age of from six months to two
years, it is very doubtful if one child in many hundreds will be found
whose blood is not more or less thin and watery and whose whole phy-
sique is not modified by malaria. Whatever intercurrent disease or
symptoms such children may eventually exhibit, it is certain that
malaria is the primary cause at work in bringing about their death. In
some instances seen by us malaria seems responsible for the almost
complete absence of children among certain communities, nearly
every child dying within a year or two of its birth.
Coolie anĉmia.-Though adult coolies shortly after they first enter
the district may be found exhibiting the typical clinical symptoms of
acute malaria, they soon present an entirely different picture in which
"fever" is subordinated to intense anĉmia. Such anĉmia is apt to
suggest anchylostomiasis, but in the Duars it is nearly always malarial
in origin.