SANDFLY FEVER. "Sandfly" or "phlebotomous fever" is an acute specific fever, common in tropical and sub-tropical countries. It is caused by a virus, possibly a leptospira, conveyed to man by the bite of a small midge of the dipterous family, Psychodidae. The incubation period is about five days.
Symptoms and Treatment.—The fever is sudden in onset, and of short duration, accompanied by severe headache and pains in the limbs. The attack starts with a general feeling of de pression and loss of appetite, soon followed by weakness of the legs, and pains and tenderness in the muscles, especially those of calves and back of neck. The temperature rises rapidly to 102 to 104° Fahrenheit. There is flushing and fulness of face and eyes as though some constriction were being applied around the neck.
The bloodshot eye is typical and in some countries has led to the disease being called "dog disease" (Hundfieber). Frontal headache and pains in the eyes and leg muscles are usually severe.
The pulse is relatively slow throughout. There may be vomiting and diarrhoea. Rashes are uncommon and are not to be confused with insect bites. A blood examination shows a marked decrease in the number of white blood corpuscles. The temperature usually falls to the normal level within four days, although one- to seven day types of fever are to be seen. Recovery is slow, depression and other nervous symptoms may persist for weeks or months.
As regards treatment, the sooner the patient takes to bed the less severe are the pains likely to be. The bowels should be moved by means of calomel, followed by salts. Then the aches and pains may be relieved by the administration of 1 o grains of aspirin every four hours, or by half a teaspoonful of liquid extract of opium.
Quinine is useless. Hot tea is very soothing for the pains, especially during the night. It is advisable to surround fever cases with a saridfly net to lessen the chance of the infection spreading. Tonics and a change of climate may be necessary dur ing convalescence.
Sandfly fever is liable to occur wherever the P. papatasii can
breed, i.e., where for eight consecutive weeks the mean daily temperature lies between 65° and 9o° Fahrenheit.
Epidemics of the fever depend on the number of infected Phlebotomus, and the number of susceptible people. Other con ditions, such as temperature, humidity, winds and reaction of soil, may modify the prime factors.
Doerr in 1909 and Birt in 1910 showed that, in sandfly fever, the blood of man is infective by direct transmission to other men only in the first day of disease. Kilroy in 1909 infected himself by Phlebotomus bites, and, by inoculation of his blood trans mitted the disease to a non-immune subject. Birt in 1910 showed that the virus could pass through a very fine filter. In 1921 Couvy reported that spirochaetes had been seen in cases of dengue in Beirut. In the same year the Royal Air Force Sandfly Commission isolated a leptospira in six cases of so-called sandfly fever in Malta, while in 1922, Vervoort and Van de Velde, work ing in the Dutch East Indies, found leptospira in cases of fever resembling phlebotomous fever. However, the correct diagnosis of some of these cases was doubtful, and until further transmis sion experiments have been carried out this organism cannot be accepted as the causal virus.
During the years 1907 to 1922, parts of the bionomics of the sandfly had been worked out, but its life history was not fully elucidated.
The R.A.F. Sandfly Commission, working in Malta and Lon don during 1921, 1922 and 1923, bred the sandfly in captivity and extensively studied the bionomics of this insect. The fever was transmitted to man by the bites of Phlebotomus bred in captivity in London, showing that these flies were the true car riers of the disease. Further experiments showed that the in fection was handed on from generation to generation of sandflies in its breeding grounds, by the grub feeding on the excreta and dead remains of the parent flies.