Health > Investigations on human trypanosomiasis in Mozambique

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have become adapted to living in other blood-sucking flies, in which they pass through
their cycle of evolution, and that those flies are thus constant carriers of the infection.
The other hypothesis is that the trypanosome in the districts of Lourengo
Marques and Inhambane is a different flagellate, and that in blood preparations it
presents various forms, some resembling the T. congolense and others the T. vivax.
All this points the way to a programme of research to be carried out as a result
of the work done by this medical mission and other previous missions.
I was instructed to draw up this programme by telegram (February 24th,
1928, from the Minister to the Governor-General), which stated that I was to arrange
for the continuance of the work.
In my view, the programme should be as follows :
1. The eastern zone of the Nyasa Company’s territory should be inspected as
carefully as was done in the case of the western zone — from the post of Lucinge
to the coast and from the Rovuma to the Lurio. Efforts should be made to ascertain
the endemic foci of human trypanosomiasis and to find out whether those already
reported by foreign authorities, including the Health Organisation of the League of
Nations, still exist.
For this purpose, blood films should be obtained from patients and suspects,
both thin-film preparations made by the Jancso-Rosenberger process and also thick-
film preparations being collected. Thin preparations should be stained by some
modification of the Romanowsky process (I found the Leishman method most
successful).
Thick preparations should be haemolysed by the use of Giemsa solution diluted
in the proportion of one drop to two cubic centimetres of distilled water, accurately
rectified with reference to its acidity ; they should be carefully washed in a container,
but should not be placed under a jet of water ; they should then be stained by the
Leishman process.
The slides should never be blotted but should be allowed to dry themselves.
This was the method I found to give the best results.
A similar process should be followed with the juice obtained from gland puncture.
If possible, trypanosomes would be sought in the blood obtained by veni-puncture
and subjected to repeated centrifugalisation by Martin’s process.
In advanced cases, it is advisable to analyse the cerebro-spinal fluid obtained by
lumbar puncture.
The slides should be very carefully examined, the whole area of the preparations
being covered, because it often happens that trypanosomes are very rare in the blood
of infected persons and sometimes in the glandular secretions also.
The whole difficulty lies in stating definitely that any given suspected case is
negative.
An examination of this kind will also reveal pathogenic blood parasites, such as
malaria parasites, spirochaetse, embryo filariae, etc.
2. A study of the geographical distribution of the various strains of glossinse
in this territory should be undertaken at the same time and they should be classified
by Austen’s and Newstead’s methods.
3. Recently collected specimem^-efThese insects should be dissected to ascertain