The American Journal of Tropical Medicine and Hygiene - Volume s1-27, Issue 3_Suppl, 1947

Malaria was the most serious health hazard experienced by American troops in the South Pacific area during World War II. In spite of the fact that for many years we have known much about the etiology, treatment and prevention of malaria and the Army and Navy have long been aware of its military importance, this disease attacked approximately 100,000 men of the armed forces in the South Pacific, and for a short time jeopardized the success of the military campaign in that area. This situation, including difficulties in the transport of malaria control supplies and inadequate local provision for malaria control organization and malaria discipline among troops, was more serious in the Pacific during the early period of the war than in any other theatre or at any other time.

Fortunately, this undesirable situation was soon corrected and commanders, previously unimpressed with the military importance of malaria, took active steps to wage a campaign against the disease.

We are grateful to Brigadier General Earl Maxwell, United States Army, Surgeon, United States Army Forces in South Pacific Area; to Captain Arthur H. Dearing, United States Navy, Force Medical Officer, South Pacific Area; to his successor, Captain Frederick R. Hook, United States Navy, and to Brigadier J. W. Twhigg, Director Medical Services, New Zealand Expeditionary Forces, Pacific, for their constant support of the South Pacific Malaria Control Organization and its work as described in the following pages.

We wish it were possible to give recognition to all those who aided in this work. Unfortunately this cannot be done. Special acknowledgement is made of the noteworthy contributions of Commander James J. Sapero, Medical Corps, United States Navy, Malaria and Epidemic Control Officer, South Pacific Area and of his successor, Commander F. A. Butler, United States Navy.

A. Introduction. The epidemics of malaria and other tropical diseases which afflicted our troops in the South Pacific as they moved against the advancing Japanese called forth an organization and methods of prevention which proved that such diseases need not jeopardize the success of military operations in the tropics. The South Pacific Malaria and Insect Control Organization 1 was a joint Army-Navy-Allied group, and while these papers are concerned primarily with the organization of Army personnel, it is to be emphasized that the cooperative spirit within this joint service organization contributed immeasurably to its success. The broad outline of the problem has been described by Sapero and Butler, (1) 2 and the control program, by Butler (2). This and subsequent sections in this series of papers make free use of material from a confidential report, since unclassified. 3

Malaria rates of all forces on the major bases in the South Pacific Campaign are presented with brief histories of each base. Similar data are presented for selected army units which proceeded from base to base. A brief account of the dengue epidemics on New Caledonia and Espiritu Santo is given.

The island bases constituting the South Pacific area have been enumerated and discussed elsewhere. 1 The entomological report here presented applies to the 11 malarious bases only unless other islands are specifically indicated, and most of the information given is drawn from observations made on Efate, Espiritu Santo, Guadalcanal, and Bougainville. Whenever possible reference is made to published data used in connection with the preparation of this paper, but we have also drawn freely from unpublished reports prepared by the numerous entomologists who at various times contributed to our knowledge of problems of medical entomology arising from our military occupation of these tropical bases.

Little detailed information regarding the insect fauna of these islands is available, and it is not within the scope of this paper to attempt generalizations as to the origin or affinities of the fauna.

• 1.  Malaria parasitemia rates among natives of the Solomon Islands, New Hebrides and Bismarck Archipelago as determined by malaria survey units in the South Pacific between 1942 and 1944 are presented. They show that malaria is hyperendemic in this area.
• 2.  Plasmodium vivax was the most common species encountered in these surveys. P. falciparum was second in incidence, and P. malariae third. Relative incidences of the three species varied on the different islands.
• 3.  The incidence of splenomegaly among natives varied from 34% to 85% on the different islands, but on most was between 50% and 75%.
• 4.  The incidence of microfilariae of Wuchereria bancrofti among the natives varied from 4% on New Caledonia to 39% on Emirau. The rate was 22% on Guadalcanal and Espiritu Santo, 24% in the Samoan area, and 30% in Fiji.
• 5.  Nocturnal periodicity of microfilariae was noted on Guadalcanal, Espiritu Santo and Emirau. There was no periodicity in Samoa or Fiji.
• 6.  Wuchereria malayi was found in 9% of imported Indo-Chinese laborers on Espiritu Santo, but not among the natives on any of the islands surveyed.
• 7.  In the early part of the South Pacific campaign, the predominant type of malaria among troops was caused by P. falciparum. The falciparum-vivax ratio decreased progressively, so that in the latter part of the occupation vivax malaria was far more common than falciparum. This shift was associated with a marked decrease in the general incidence of malaria.
• 8.  Upon removal of troops of troops from a malarious area, P. vivax rapidly became the predominant cause of malaria.