116
Two water-base insecticides, "Deskito" and "Multicide", were tested;
but using a 7 per cent solution a concentration equivalent of 20 cc. pure solu-
tion per 1,000 c.ft. is required for killing.
The Phantomyst sprayer does not appear to have any real advantage over
hand sprays.
An effort has been made to determine the maximum altitude at which
P. papatassi is found. The flies exist in large numbers at Landi Kotal, at
3,500 feet, where the disease is met with in epidemic form during the hot
weather period. At Cherat (4,500 feet) at a distance of 40 miles; and Abbotta
-bad (4,000 feet) distance 110 miles, the fever is reported as occurring in sporadic
form, suggesting that the cases are either imported from the plains, or else
incorrectly diagnosed. In each of these places, a trained collector worked for
two weeks, and the collection of flies brought down were despatched to Guindy
for identification. No P. papatassi were among the specimens found at Cherat
and at Abbottabad only two were noted in the collection examined.
Examination of earth samples for sandfly's larvae has been carried out
by means of a special apparatus, in which the soil is broken up in a concentrated
solution of magnesium sulphate and the supernatant material floated off to a
settling tank and thence to a filter paper on a Buchner funnel. Of fifteen
specimens examined, two have been positive, both of which were taken from
shady places and contained a fair amount of moisture.
Laboratory Work.
Sera have been collected, during the first three days of fever, from seventy
-eight cases of suspected sandfly fever. After dessication by a process of
freezing in vacuo, over sulphuric acid, these sera were despatched to the King
Institute for further examination. In Peshawar, seventy of these sera have
been tested for the presence of virus by chorioallantoic membrane inoculation,
with results as follows:
—
Present 40, absent 16, presence uncertain 14.
An experiment was performed to investigate the effect of the dessicat-
ing process on bacteria contaminating serum. Suspensions of four organisms,
which may be considered as possible laboratory contaminants, were kept in
a frozen state (at 18° C.) in vacuo over sulphuric acid for a period of 12 hours,
and then transferred to a dessicator, where they remained in vacuo over the
acid for a further three days. Three of the organisms, i . e . ,
s t r a i n s o f B . c o l i ,
Flexner's dysentery bacillus (A-1) and Staphylococcus albus were still viable
at the end of the process, and only one (Streptococcus viridans) failed to
survive.
Fifty-one specimens of serum have been collected from sandfly fever
convalescent patients, at intervals of 40 to 180 days from the date of the
onset of the fever, and are being despatched in an undried state to the King
Institute for the investigation of neutralising antibodies. In an attempt to
minimise the effects of external temperature on the five day journeys from
Peshawar to Guindy, these sera are being packed in vacuum flasks.
The serial passages of the virus on egg membrane and in flask culture
have been maintained. In the former the virus is at its 73rd passage and
in the latter at its 67th passage.
The sera received from Peshawar were tested for the presence of virus
in the Institute at Guindy. In the majority of sera tested at Guindy, the
presence of virus could not be demonstrated. It appears the sera were sub
-jected to abnormal temperatures during transit, which factor among others
probably accounted for this failure.