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on the numbers of microfilaria in the peripheral blood have been studied, and also the effects of prolonged fever with high temperature, not filarial.
Clinical. The clinical manifestations in the islands visited have been noted and compared with those existing in other previously investigated areas.
Owing to the accidental infection of my assistant, Mr. C. E. Berry, during feeding experiments with infected mosquitoes, I have been able to observe several early clinical signs of filariasis so far not described. I have since been able to con- firm these findings by observing a number of newly arrived Europeans, joining the new Government in Samoa.
As the result of studying a large number of cases of filarial and elephantoid fever, my views as to the exciting cause of these attacks has undergone modification from previously accepted beliefs and theories, Observations have been made on the periodicity of recurrence of these attacks, as well as upon the greater frequency of attacks under certain physiological conditions.
The Transmission of Filariasis.-The arthropod host of the microfilaria bancrofti was not previously known in these three groups of islands. By several series of experiments with mosquitoes specially bred out for the purpose and fed on patients harbouring microfilariæ in the blood, the insect host of the parasite has been scientifically demonstrated.
By the dissection of a large number of captured mosquitoes of different species it has been possible to confirm the above experiments, and what actually pertains in nature has become manifest; as these mosquitoes were captured in different classes of localities some interesting information has been gained as to the conditions under which they are liable to become infected.
Experiments have been conducted with a view to ascertaining if the larvæ filaria, after completing its mosquito phase, can penetrate the skin of man, direct from water.
Treatment-Cases of filariasis have been treated by intravenous or intra- muscular injections, or by mouth with the following drugs:-Novarsenobillon, kharsivan, galyl, antimony ammonium tartrate, stibenyl, quinine, emetine, and quassia, and with the collosols of copper, selenium, and manganese: these have been controlled microscopically and clinically, and some cases are still being controlled for me by my late assistant. As far as possible, the cases chosen for treatment, in addition to having microfilaria in the blood, were suffering from frequently recurring attacks of filariasis or elephantoid fever. The effects of some of the treat- ments on clinical filariasis are worth recording.
All the drugs mentioned above were further tested, in varying dilutions, on living microfilaria in freshly drawn blood, the latter being kept in moist chambers. Mosquito Work The mosquitoes collected in the various islands are being classified. Two additional species, not so far included, are to be added to the Culicidæ of the Samoan group. The reasons for the absence of some species in one island or group, while present in a neighbouring island or group of similar geological formation, has been made clear.
The life histories, not previously described, of two species of mosquito, of which one is of much medical importance, and the other possibly so, have been worked out; as a result it may be stated that as regards the former, its eradication in some islands, and a considerable reduction in its numbers in all, is well within the scope of practical sanitation. In consequence, if efficient measures are adopted, there should be a prompt and marked amelioration of one of the most prevalent scourges in these parts of the Pacific.
Owing to the number of islands visited, it has been possible to study the relation of the transmitting mosquito to the filarial incidence amongst the inhabitants, and the reasons for the marked variation (1) in the filarial incidence and (2) in the severity of the clinical manifestations in different islands of the same geological composition and group have been apparent.
Ankylostomiasis: Samoa.-On my arrival, though the existence of this disease was known to the medical faculty, yet the great prevalence and far reaching results of the infection were not understood. I was able by examination of a large number of people to give reliable figures as to the incidence and to point out to the authori- ties the probable bearing of this infection on a recent grave disaster in the group, as well as upon unfortunate results in hospital practice that were occurring far too frequently. The Samoan Government has now started an anti-ankylostomiasis campaign.
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Ellice Islands and Tokelau Islands.-The late Medical Officer of these groups informed me that he did not believe in the existence of the infection in these atolls. From a supply of thymol in the hospital at Funafuti, not a single dose had been administered. I found that the incidence of infection was well over ninety per cent. The effects of this disease as regards the great susceptibility to other infections are very marked in the Ellice group.
Ascariasis. While "Ascario lumbricoides" is very common in one group of islands, I failed to find a single infected case in another group. The reasons for this phenomenon have been studied, and some light may be thrown on the subject. In connexion with this infection a comparative study of the mental and working capacity of the natives in these two groups of islands has proved very interesting.
Other Intestinal Parasites: Helminthic and Protozoal.-A large number of stools have been examined in the various island groups, and some knowledge has been gained about these parasites. Some of the protozoa of comparative rarity in northern tropical countries are far from uncommon in these islands.
Blood Examinations.-In connexion with the afore-mentioned investigations some hundreds of blood examinations have been made according to the following routine: Microscopical for morphology, total red counts, total white counts, differential white counts, hæmaglobin percentage and colour index. There are many points of interest in the blood picture in these islands.
Fish Poisoning. This condition, which sometimes incapacitates whole families, is very common in the Southern Ellice, less so in the Tokelau and Samoan Islands, and absent in the Northern Ellice. It is not caused by specific fish, and one species very poisonous in one locality may be perfectly harmless a few hundred yards away in another locality. This condition has been carefully studied, and experiments with susceptible animals has resulted in some interesting information.
Yaws has been studied in all the islands, and especial notice has been taken of its great prevalence in the Northern Ellice and slight distribution in the southern islands of the group.
Leprosy, which appears from time to time in Samoa, where I diagnosed about six cases, has not been seen in Ellice Islands, though it is comparatively common in the neighbouring Gilberts.
Tuberculosis. The widespread ravages of this disease in the Northern Ellice and to a slightly lesser extent in the Southern Ellice, Tokelau, and Samoan islands has occupied much attention in this work, and information has been gained concern- ing the rapid dissemination, of the disease, which seriously threatens the very existence of the Ellice islanders.
Animal Examinations. A considerable number of animals, pigs, horses, cattle, sheep, cats, dogs, and rats (Mus exulaus), as well as various species of birds, have been examined for blood worms and other parasites. In the intestines of pigs in some of the islands parasites, helminthic and protozoal, have been found bearing a close resemblance to some common parasites in man.
Other Studies. Amongst the subjects of interest which have been studied are: The epidemic ophthalmia of Samoa. Poisoning by native drugs and beverages. The deleterious effects of some native treatments and the possible efficacy of some native herbs if properly extracted and prepared. The very low incidence of venereal disease with the probable absence of genital gonorrhoea and the possible explanation. Native methods of procuring abortion. The sting of certain arthropods and the prevalence of septic coral sores.
Many of my observations are still being controlled, and new lines of investiga- tion suggested by me are being carried out by my late assistant, Mr. C. E. Berry, from whom I will receive further reports, as well as much more material, in the near future.
F. W. O'CONNOR.
Co
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