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Medical Services in New Zealand and The Pacific

VIII: Malaria Control and Incidence of Sickness

VIII: Malaria Control and Incidence of Sickness

Potentially malaria was the biggest hazard to the health of personnel posted to the Pacific zone west of the 170 degree parallel. The incidence in the United States ground forces in the initial stages of the Solomons campaign was as high as 90 per cent in three months, and the probability that our forces would suffer a high incidence was a factor in specifying a limited tour of duty in malarial zones. The low incidence which occurred in RNZAF personnel was due to good control measures, which relied on adequate education in personal protection, major draining schemes, and the keeping of natives at a safe perimeter.

Medical officers were responsible for malaria-control measures in their units. They were assisted in the detailed execution of this work by specially selected orderlies who were given a course of training in the entomological and practical aspects of control at training schools set up by the Fiji Government medical services and by the United States Forces. One orderly so trained was posted to each servicing unit and he had four field assistants.

The responsibility for adequate instruction of all personnel in the rationale of corporate and individual control measures rested largely with the unit medical officer. This task was made easier from 1944 onward when courses of instruction with more detailed courses for page 233 all officers and NCOs were given to all ranks at the Embarkation Depot.

When moving to recently-won ground, American forces sent in heavy earth-moving machinery at the earliest possible moment. Some concentrated on building an airstrip, but others were put to work at once on the drainage and filling of the proposed camp area. These major drainage schemes were a masterly attack on the control problem and were largely responsible for the ultimate clearing of the longer-established camps. But the nature of the terrain made organised and detailed spraying with oil and kerosene the line of attack when moving to new territory, even after 1944 when spraying of DDT by aircraft was introduced.

In the closely confined space about an airstrip, when many different units and organisations were grouped, each unit was very dependent on the thoroughness of the control measures of other units. In general there was little cause for complaint, but one of our medical orderlies who did some original work in species classification in the Solomons maintained that he could find all the specimens he required in other units' terrain.

Systematic control measures rapidly brought the mosquito population under control, and the standard use of atebrin lowered the incidence of overt malaria so that even in forward areas an unwarranted sense of security tended to arise. This attitude, combined with the enervating climate, made it easy to be casual in the use of mosquito netting and protective clothing, and this undoubtedly accounted for the sporadic cases of malaria which continued to occur even in long-established camps. In such circumstances a commanding officer who was convinced of the necessity for strict personal discipline could do much to reduce the incidence in his unit. Unfortunately all executive officers were not in this class, and it seemed to be chiefly in this respect that our control was behind that of the best American units.

By 1945 it was possible to abolish personal protective measures at Espiritu Santo and Guadalcanal, but in all other malarial zones they were utilised throughout the campaign.

The rapid growth of aircraft movement in the Pacific caused all countries beyond the malarial zone to take urgent measures to prevent the introduction of anopheline mosquitoes.

The spraying of aircraft in flight with pyrethrum aerosol dispensers was theoretically an ideal method, which failed in practice due to the difficulty of adequately spraying all compartments of the aircraft and lack of responsibility on the part of the crews. On all RNZAF stations spraying on arrival before unloading passengers or freight became standard practice, and was the responsibility of page 234 the medical section. In addition, possible breeding grounds in the vicinity of overseas airports were treated.

Anopheline mosquitoes did not spread to Fiji or New Caledonia, the two most vulnerable areas, despite the fact that live specimens were occasionally found in aircraft, and that male specimens thrived in captivity in these countries.

Atebrin prophylaxis was enforced in all forward areas and was undoubtedly effective in reducing morbidity rates overseas if not the ultimate incidence of infection.

This is shown by two facts:


Medical officers found that only about 10 per cent of cases presented a picture that could be recognised confidently on clinical grounds. In most cases the diagnosis was made only after repeated blood examinations in men with vague asthenia or muscular pains, or with a persistent tracheo-rhinitis or gastritis.


One-third of all primary cases did not suffer recognisable malaria overseas and were diagnosed for the first time in New Zealand, usually several months after their return. Our blood smears in many cases were examined in laboratories of allied medical units and the technicians in some cases did not inspire confidence, but this high incidence of primary attack in New Zealand was due to adequate suppression overseas and not due to inadequate diagnostic facilities.

Of all men who served in malarial zones 4.55 per cent contracted the infection: 3.4 per cent had the primary attack overseas and 1.15 per cent in New Zealand.

It was to be expected that aircrew, with a shorter tour of duty and, in many cases, with better living quarters, would have a lower incidence, even though a few of them were inevitably infected due to forced landings in hyperendemic zones. They had an incidence not quite half that of ground staff.

Treatment was carried out in station sick quarters on a standard atebrin, quinine, plasmoquine regime, and it was effective to the degree that, although there was a relapse rate of 30 per cent (mostly after return to New Zealand), only seven men out of 10,000 had to be repatriated to New Zealand on account of malaria.

At first all personnel returning from the malarial zone were given a course of treatment on arrival in New Zealand, whether or not they had clinical haematological evidence of infection. It is difficult to assess the value of this scheme, which was abandoned in August 1943 because of its increasing impracticability and the relatively low incidence overseas. It was replaced by the taking of a blood smear from all returned personnel on disembarkation, and the few cases so discovered were retained for immediate treatment.

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Malaria, Jan 1943–Jul 1945
Aircrew Ground Staff Total
Men returned 2036 9144 11,180
Number attacked overseas 41 283 324
Primary attacks in New Zealand 11 107 118
Relapses in New Zealand 10 85 95
Health of the Force

Deaths in the Pacific theatre totalled 345 and occurred almost exclusively in aircrew personnel. They were due to:

Enemy action (and lost and missing on operations) 256
Accidents (flying and non-flying) 82
Sickness 7
Wounds and serious injuries due to enemy action 58

Sickness: While overseas each man reported sick, on an average, twenty-three times a year – much more often than in New Zealand – but the non-effective rate due to sickness and injury was consistently and often markedly lower than on New Zealand stations. From August 1943 to March 1945 it was just under 2 per cent for the Solomons-New Hebrides area and about 3 per cent for Fiji.

There were several factors responsible for this low incidence of sickness. They were:


The men serving overseas had successfully passed at least three examinations by service medical officers before leaving New Zealand and therefore could be said to measure up fully to our standards of fitness for tropical service.


The great majority of the ground forces at no stage experienced enemy opposition. In the early stages at Espiritu Santo, Guadalcanal and Bougainville there were restrictions and interruptions due to air raids or artillery fire, but this enemy action was never severe and did not disrupt essential medical, sanitation or anti-malaria services. Under different circumstances the incidence of such conditions as malaria and dysentery could be entirely different.


Despite the low non-effective rate the high sick-parade rate must be accepted as an index of morbidity, even though it was of minor nature. It could have been due to low morale or to a high incidence of organic trivia. Certainly the first factor operated and sick-parade rates varied in relation to the morale of the unit, but it was largely due to the accepted policy that all conditions should be reported, especially skin rashes and minor traumatic injuries, that the attendance rate was high. The rapidity with which certain of these conditions deteriorated due to neglect in the tropics warranted page 236 this policy, and under circumstances where it could not be carried out it would be reasonable to expect a higher incidence of morbidity from these causes.


In general the facilities for personal hygiene were good. In some cases good surfing was possible and was a great asset, but water was plentiful enough in almost all areas for showers to be freely available. This again was an advantage made possible by the relatively static state of the campaign.

To summarise, a fit man, given good medical, hygiene and anti-malaria services and not seriously molested by an enemy, can do hard work in this theatre with no more illness than he would experience in New Zealand.

Incidence of Disease

The principal groups of diseases causing personnel to become non-effective in the Pacific area are set out below.

Solomons-New Hebrides Area Fiji Area
Disabilities Approx Rate per 1000 per Year (Av.) Percentage of Total Disabilities (Av.) Approx. Rate per 1000 per Year (Av.) Percentage of Total Disabilities
Diseases caused by infection or infestation 215 24 321 39
Diseases of the nervous system and mental diseases 30 3 20
Diseases of the ear and nose 40 5 16 2
Diseases of the respiratory system 18 2 22 3
Diseases of the digestive system 162 18 147 18
Diseases of the bones, joints, muscles, fasciae and bursae 36 4 22 3
Diseases of the skin and areolar tissue 173 20 139 17
Injuries 137 16 82 10

Although the non-effective rate was lower in the Pacific area than in New Zealand, it will be noted that the proportion of personnel actually reporting sick was greater. The principal groups of diseases of which the incidence in the Pacific was considerably higher than in New Zealand were those caused by infection or infestation, diseases of the digestive system, diseases of the skin and areolar tissue, and injuries. The higher rate of diseases caused by infection or infestation was caused in a great measure by outbreaks of dengue fever and dysentery, and during the year ended 31 March 1945, when there were no outbreaks of these diseases, the actual incidence of diseases caused by infection or infestation was only 97.5 per thousand in the Solomons-New Hebrides area and 144.4 in the Fiji area. page 237 Diseases of the skin and areolar tissue were naturally higher in incidence in the Pacific area.

Skin conditions accounted for 20 per cent of the non-effective rate, and in some degree or other all personnel were affected at some stage of their service. Wing Commander Forrest1 described the following conditions:


The weeping dermatoses were the most common and would usually respond to early treatment. Where the response to complete bed rest and local treatment was delayed it could almost always be found that the man had an eczematous background, often so remote or so mild that it had been regarded as insignificant by him or his medical officer in New Zealand. Such cases were difficult to cure completely and many had ultimately to be repatriated.


Fungus infections were usually acute and short-lived and were almost never due to an extension of a pre-existent lesion. In fact, men who had been troubled with recurrent mild tinea of the feet in New Zealand found that the condition remained healed overseas, where much more attention was paid to foot hygiene.


Indolent tropical ulcers due to a low-grade mixed infection in an abraded wound, usually of the shin, were a potential source of prolonged incapacity. The basis of treatment lay in early recognition, prevention of vascular stress by elevation or elastic support, and the use of an adequate bacteriostatic agent in a non-adherent and bland base. Once fibrosis of the ulcer edge occurred, healing became a slow and tedious process. The RNZAF introduced propamidine cream in the treatment of these cases, with good results.

Infections and infestations were twice as common as in New Zealand and accounted for 25 per cent of all non-effective states. This is not a high figure for tropical service and reflects the general adequacy of the hygiene services. More important, at no stage was there any particularly high local incidence. Of the three chief infections, malaria, enteritis and dengue fever, it was the last which caused the highest incidence on any single station. The outbreak occurred in Fiji in January-March 1944 and it demonstrated the difficulties of adequate mosquito control when situated near a large civil population, and the difficulties in dealing with a day-biting vector. Many of the cases were severe, with a degree of prostration and long convalescence that was not equalled by the usual malaria cases.

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Functional diseases of the nervous system, chiefly mild neurosis, accounted for 3 per cent of the cases of unfitness in the Pacific, and this type of disability was the main cause of medical repatriation.

Conditions in this theatre presented some problems which were particularly conducive to the lowering of morale and the manifestation of these functional disorders.

For the great majority of ground staff an overseas posting meant twelve to eighteen months in a zone with an enervating climate, entirely male company and no 'leave' prospects. In the early stages of the campaign physical conditions were hard, but there was considerable evidence of enemy activity and morale was high. As the campaign advanced enemy activity lessened and so did the urgency of the task. Various 'contests' and organised distractions were provided but could not compensate for the lost stimulus of enemy interference. Certainly, under conditions of considerable and prolonged activity, functional disorders would have become more apparent, but it was the experience of all medical officers that the cases which occurred were based on inactivity rather than on apprehension, and that an occasional 'nuisance' air raid was the best boost to morale which a unit could experience.

All men who returned from a tour of duty were examined immediately on arrival in New Zealand and their fitness for further tropical service assessed.

After the first tour by 9068 personnel (1710 aircrew and 7358 ground staff), 80 per cent were fit for immediate return and only 5.6 per cent were regarded as permanently unfit to return to the theatre. The main cause of unfitness was nervous disease.

Causes of Medical Repatriation, May 1943-September 1945
Type of Disease Number of Cases Percentageof Total Repatriations
Nervous and Mental Diseases 241 24.9
Injuries 164 17.0
Skin Diseases 125 13.0
Bones, Joints and Muscles 78 8.1
Digestive Disease 73 7.6
Infections 53 5.5
Respiratory Diseases 49 5.1
Ear Diseases 36 3.7
Nose Diseases 29 3.0
Urinary Diseases 24 2.5
Eye Diseases 22 2.3
Circulatory Diseases 16 1.6page 239
Tumours and Cysts 15 1.5
General Debility 14 1.4
Infected Wounds and Tropical Ulcers 13 1.5
Generative Diseases 11 1.1
Metabolic Disorders 2 0.2
Endocrine Glands 1 0.1
Teeth and Gums 1 0.1
Totals 967 100.0

The strength of the force varied from 1600 in May 1943 to 7600 in May 1945. The average strength was approximately 4750.

1 Wg Cdr G. H. Forrest, OBE; New Plymouth; born Palmerston North, 16 Oct 1915; medical practitioner; SMO Fiji, Dec 1942-Sep 1943; Solomons, Sep 1943-Apr 1944; ADMS (Air) Jul 1944-Sep 1945; DMS Sep-Dec 1945.