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War Surgery and Medicine

CHAPTER 7 — Sandfly (Phlebotomus) Fever

page 554

Sandfly (Phlebotomus) Fever

SANDFLY fever is a disease of considerable military importance because, although it is never fatal and has no serious sequelae, it may nevertheless suddenly incapacitate large numbers of men who may be urgently required for important operations.

It has long been endemic in the Mediterranean area and persists chiefly in the lowlands of those tropical and subtropical countries which have long periods of hot dry weather. The native population seems to be immune, probably because of infection in childhood. Newcomers, however, usually succumb to the disease during the first epidemic.

It is not surprising therefore that when British and Dominion troops entered the Middle East area large-scale epidemics occurred, and it is reported that about 25,000 cases were admitted to hospital.

Among the New Zealand troops about 2000 cases occurred, largely in the summer months. No reliable figures are available before July 1941, but it is known that many cases occurred before this. In addition many cases diagnosed as PUO were considered to be mild cases of sandfly fever.

Figures of incidence from July 1941 to October 1945 for 2 NZEF in the Middle East are as follows:

Sandfly Fever
1941 1942 1943 1944 1945
Mar 1 2 2
Apr 4 15
May 88 24 2 3
Jun ? 213 55 3 8
Jul 134 79 78 4 4
Aug 205 133 62 39 6
Sep 205 95 42 72 5
Oct 73 45 63 18 1
Nov 30 14 17 4
Dec 3 6

Sandfly fever is due to a small virus which is present in the blood of a patient from twenty-four hours before till twenty-four hours after the onset of the disease. The virus can be readily page 555 transferred to volunteers by intravenous or intracutaneous injection. It has not so far been transmitted to lower animals.

In nature the disease is transmitted by the bite of the female of a small midge Phlebotomus papataci. There was no evidence in the Middle East that any other insect was concerned in transmission. These small insects bite during the night and early morning hours and are found near ground level. They avoid higher levels and strong breezes, and have a very short range of flight. It is thought that they seldom move more than fifty yards from their breeding places. They breed in rubble, cracks in walls, dugouts, and similar areas.

Sandfly fever first became a major problem among New Zealand troops in Egypt in June 1941. At this time a particularly severe epidemic occurred in 3 NZ General Hospital at Helmieh and Captain Sayers was sent to investigate the outbreak.

This hospital was a tented hospital situated on the edge of the desert. To guard against bombing the sites of the tents had been excavated several feet and then native workmen had built round each tent walls constructed of mud bricks. It was hoped that these walls would act as protection against bomb blast.

The epidemic started during the third week in June and appeared at first to affect mainly officers and NCOs. It soon spread not only to practically the whole staff, but also involved the patients. So bad did the situation become that it became necessary to close down the hospital completely for a short period.

Captain Sayers was able to establish that Phlebotomus papataci was breeding in large numbers in cracks in the brick walls which had been built a few months earlier round both the hospital tents and those used by personnel. Conditions in these walls were apparently ideal for breeding, and during the night and early morning hours the insects came out of their hiding places and infected the inmates of the tents.

Apart from this outbreak, there were no serious outbreaks among units of 2 NZEF, and at no time were divisional operations upset by sandfly fever, although each summer in the Middle East there were a number of cases from both field and base units, the incidence being fairly high in 1942. Sandfly fever was endemic in Syria, and admissions to the CCS rose in May 1942 and were rapidly increasing in June when the Division left Syria to return to the Western Desert.

Clinical Aspects

Few soldiers who suffered from sandfly fever will forget the three days of misery they suffered, and many will remember the page 556 days or weeks of debility and depression which followed the illness. The main clinical features were as follows:

Following an incubation period of three to six days the disease commenced with explosive suddenness. The temperature rose abruptly to between 102 and 104 degrees F. and remained there for between two and four days. Occasional cases were febrile for somewhat longer periods, and occasionally there was a slight recrudescence of fever after the temperature had become normal.

Headache was usually severe and distressing and was retro-orbital and frontal. This was associated with malaise and prostration and general aching of the limbs and back. Many patients complained of a feeling of stiffness in the neck and occipital pain.

The eyes were sore and movement of the eyes was very painful. On inspection there was usually marked conjunctival infection.

During the course of the disease, and indeed frequently for some days or even weeks afterwards, there was almost complete anorexia, and some patients complained of nausea. A minority vomited.

In some cases there was a slight congestion of the throat, but, generally speaking, this was not a marked feature. Although there was often a distinct flushing of the head and neck there was no rash such as one sees in dengue. Unlike dengue, too, lymphatic glands were not generally enlarged. After the temperature had returned to normal many patients still felt weak, mentally depressed, and had little appetite. Many lost a considerable amount of weight. There were no deaths from the disease and no known sequelae.

Blood examination usually showed a leucopenia with a shift to the left of the neutrophils.

After the epidemic at the Helmieh hospital in June 1941 real progress was made in the control of sandfly fever. Great care was taken in making camps not to create suitable breeding places for the mites, and whenever possible the area round sleeping quarters was freed of walls, banks, rubble, and other likely breeding sites.

It was proved that dimethyl-phthalate was an effective repellent against phlebotomi and that DDT spraying would apparently almost eliminate the infecting insect.

Sandfly nets were provided at times in 2 NZEF, and DDT-impregnated mosquito nets were used later. Nursing patients with sandfly fever under nets diminished the risk of spreading the infection. In Italy few cases were recorded and in the Pacific none.