11 Sep 45
- JAPAN consists of four main islands – HOKKAIDO, HONSHU, KYUSHU and SHIKOKU sub-divided into 47 administrative districts. Of these, 43 are prefectures (ken), 3 are the urban districts of TOKYO, KYOTO and OSAKA, and one, the island of HOKKAIDO. The islands carry a population of 73,140,308.
- HOUSING:
In the larger cities, particularly those subject to earthquakes, business premises and the dwellings of the wealthy are commonly of European design and construction. The great majority of dwellings however, are built in Japanese style. These consist of a heavy roof of tiles, shingle or thatch supported by columns of superimposed stones set upon the ground without foundation. The dwelling itself is a light timber framework standing below the roof with air spaces below the floor and above the ceiling. There are no cellars nor attics. Commonly dwellings are of one or two stories, rarely more than 3, the upper stories covering only part of the lower and being reached by steep steps or ladders.
In country houses there are no true walls, exterior or interior. At night, wooden sliding doors (Amado) are fitted to the outside frame. These are taken down and stowed away by day. In winter these Amado are replaced by day with sliding frames covered with semi-transparent paper (shoji).
In cities most houses have permanent side-walls of light wooden boards.
The dwelling is divided into rooms by opaque paper sliding doors running in grooves at top and bottom. Passages are few, each room opening through a sliding panel into the next.
Floors are covered with thick rush mats of standard size (6ft x 3ft) fitting accurately together. The dimensions of room are determined accurately to accommodate a certain number of floor mats and the size of the room is described in terms of that number. The commonest sizes of such rooms are eight mats (12ft x 12ft); six mats (12ft x 9ft); and 4 ½ mats (9ft x 9ft). Floors are usually scrupulously clean and shoes must be removed before entering. Tables are small and low and there is little other furniture, the family sitting on cushions on the floor.
The family sleeps on quilts laid on the floor. These quilts are removed each morning and stored in cupboards with sliding doors.
The floors of kitchen and passages are of highly polished wood and mats are not used on these.
Most houses have bathrooms, the Japanese being a naturally clean people. The bathroom may have a concrete floor or an earthern floor covered by a wooden grating. The Japanese usually indulge in a daily hot bath (110 degrees F). The bath is taken in a large tub, the whole family using the same water but all soaping and cleansing is performed before the bath is entered. Fuel latterly having been short in JAPAN this bathing routine has probably become less frequent and may have been largely abandoned.
Public baths on the same principle were provided in public bathhouses where all patrons used the same water in one large tank. It has latterly been found desirable to segregate the sexes in public bathhouses but this is not always the practice in Japanese style inns.
Privies are situated immediately adjacent to the dwelling and are usually well kept and free from offence except when being emptied. Except in sewered areas or in the houses of the well-to-do where there may be septic tanks, the privy consists of a cess pit provided with a squatting platform.
- WASTE DISPOSAL
(a) Excreta:
(i) Conservancy: Human excreta is highly valued as fertilizer and is therefore made available to farmers. In cities the cess pit at each dwelling is periodically emptied into buckets and removed for sale to farmers either by the municipality or by arrangement between the householder and a contract or nightsoil merchant.
In country and farming districts removal may be by the householder himself for his own use, by a neighbouring farmer or by a nightsoil merchant. Nightsoil is officially required to be stored three months before use as fertilizer, this period being considered adequate to effect destruction of all pathogenic parasites. The storage period however, is not consistently enforced and this method of disposal is responsible for the high incidence of bowel infection and parasitism throughout JAPAN.
The process of removal occasions considerable offence but at other times the privy is clean and free from nuisance.
(ii) Sewage is chiefly sullage water drainage. In cities and towns the owner of the property must drain his premises to the sewer which is concrete surface or underground drain. Street and storm water is normally drained to the sewer but in time of flood may be diverted by surface channels direct to canals.
Sewage may either be carried to treatment plants or discharged direct into the sea or nearby rivers. Of the 6 great cities, TOKYO, NAGOYA, KYOTO and OSAKA treat the sewage before discharge; YOKOHAMA and KOBE discharge sewage direct to the sea.
Of other cities – GIFU has an activated sludge plant and TOYOHASHI one of the most modern sewage treatment installations in all JAPAN.
(iii) Garbage: The law regulating the disposal of garbage requires that in cities, towns and villages designated by the prefecture, householders must place all refuse in garbage receptacles. These are regularly emptied by a municipal service and the garbage removed to a prescribed place for incineration, burial or disposal by other methods free from danger to health. In most areas refuse is disposed by incineration either in stablished incinerators (of which there were 152 in 1938) or in open fires. In some areas, particularly in rural districts, refuse may be used as fertilizer.
- WATER SUPPLY:
Supply of water is sufficient in most parts of JAPAN but during the late summer (August) and some winter months may be inadequate in certain parts of central and southern JAPAN.
HOKKAIDO is under snow and ice for four months each year. Rainfall is fairly regular – 35 is to 45 ins annually. Upland surface water stored in ponds or rivers is distributed by irrigation canals to rice fields in the lowlands. There are, in addition, large numbers of fresh water lakes in the mountains. In most lowland areas the ground water is less than 20 ft below the surface and water may be obtained from wells. Near the coast such wells may become brackish if overpumped. Stream water is usually soft but is sometimes loaded with a heavy sediment and is also subject to heavy faecal contamination especially on the coastal plain.
In HONSHU, KYUSHU and SHIKOKU water supplies are usually bountiful. The long elevated mountain axis provides a watershed from which numerous streams flow to the coast, whilst a somewhat higher summer rainfall compensates the greater evaporation rate in that season and ensures uniformity of flow.
Divergent topographical conditions occasion sharp local contrasts in annual rainfall precipitation and make generalisations regarding area distribution difficult. Generally however, annual rainfall increases toward the South. Two regions of especially heavy precipitation are western HONSHU North of 35 degrees North latitude and the Pacific slops of KYUSHU and SHIKOKU where the annual rainfall is from 80 ins to 12 ins. On the other hand in the interior basis of Central HONSHU and the central shores of the Inland Sea, rainfall may be as low as 40 in. or 50 in. annually.
The largely granitic mountains are heavily wooded and sparsely inhabited. Water is usually soft and except in time of flood remarkably clear and free from sediment.
In most rural areas water is obtained from:
- shallow wells subject to contamination
- streams by gravity through pipes or open channels
- streams by buckets.
In 1938 there were 627 water works in JAPAN and a further 39 to be constructed, as against 141 cities, 1707 towns and 9568 villages. Moreover only a fraction of the population of each city is supplied by reticulation. In 1938, 27% of householders throughout JAPAN were supplied from water works but there was wide variation in the percentages served by different installations:-
The water is obtained chiefly from rivers, springs, streams or lakes but occasionally entirely from wells. Details of water supply in the six great cities are as follow:-
TOKYO – from TAMA RIVER mainly but also from EDEGAWA RIVER and from wells.
YOKOHAMA – from SUGAMI RIVER at AOYUMA.
NAGOYA – from KISO RIVER – slow sand filtered.
KYOTO – from HEWA LAKE.
OSAKA – from the New YODO RIVER – outlet of Lake HEWA 20 miles below the discharge point of the KYOTO Sewer – rapid sand filtered.
KOBE – from streams on mountains behind the city. Water in KOBE has been rationed during 7 years in the last decade, August being the worst month.
Filtration and chlorination are effective in the larger cities but in smaller cities chlorination is effected intermittently.
- DIET:
Consists mainly of rice, fish, soya beans, fresh vegetables and fruit. Meat and dairy produce are of relatively little importance – lack of pastures precludes any great development of the pastoral industry.
Slaughtered stock are subject to inspection by Government Inspectors but diseased stock may be slaughtered and consumed if considered safe.
Meat from stock suffering from Tuberculosis may be sold and eaten provided that not more than two viscera are affected and there is no evidence of acute disease. The diseased parts are excised. Tuberculosis is said to be rare in native cattle but is found chiefly in imported breeds.
Under a law for the control of Bovine Tuberculosis, Dairy cows must be submitted for regular veterinary examination and Tuberculin Testing. Heavily infected cattle are killed and burned but cattle with mild or suspected disease are isolated and their milk may be sold after pasteurisation at 80 degrees F. Milk handlers are required to hold permits and are subject to medical examination. Milk sold in a few of the major cities is pasteurised but results are regarded as uncertain. Rural sanitation has not progressed pari passu with urban.
Much of the fish eaten in JAPAN is consumed only partially cooked or raw and heavily spiced. Consumption of uncooked fresh water fish and certain crabs occasions a very heavy incidence of bowel parasitisation with a variety of worms and flukes for which the fish serve as intermediate hosts. Similarly the consumption uncooked of vegetables grown in polluted water or soil or carrying the encysted stages of certain parasites causes a heavy bowel infection and worm infestation rate.
- SOCIAL:
The moral code permits the Japanese male greater license than is accorded by the accepted social standards of western civilisation.
A wide variety of ingenious mechanical devices intended to enhance the physical or emotional enjoyment of the sexual act, to prevent disease or to circumvent conception, to overcome secretly or by mutual consent embarrassing anatomical disparities or functional deficiencies in either party or to serve both visually and palpably as a safe and conveniently portable substitute for the sexual organs of either sex, are manufactured, advertised and sold with a freedom and frankness astonishing to the Western observer.
With the exception of professional female entertainers, Japanese women are in contrast to the men, for the most part, retiring, gentle, dainty, chaste and homely. They occupy a subservient position in the household and the wife is subject to the authority of her Mother-in-law while the latter is alive. Families are large – the crude annual birth rate is approximately 28 per 1000 and birth control is considered a national and social crime. Family life is usually happy notwithstanding the freedom of the male but economic stress often dictates the sale of daughters into prostitution or into employment as coolies or underpaid factory hands in industrial areas.
Marriage is a social contract of convenience not necessarily determined by any emotional attitude. The bride is chosen by an accredited agent who finalises details of the contract. The divorce rate is not high although the husband may divorce his wife if she bear him no children within a reasonable period and barren marriages may be dissolved my mutual consent.
Infatuation of youths with girls other than the fiancées chosen for them is a frequent cause of double suicide. It is significant of the Japanese character that these suicides may be made the opportunity for gala excursions to an active volcano, a number of couples leaping to death in full view of the assembled spectators.
Professional female entertainers may be considered as falling into three groups:
(a) Geisha girls:
These are highly trained dancers and specialized entertainers. Whilst they have a liberal sex code they are not as a rule prostitutes nor unnecessarily without virtue. In 1938 there were estimated to be 80,000 of these girls in JAPAN.
(b) Licensed Prostitutes:
These are housed in brothels controlled by the police in prescribed brothel areas. In 1938 there were 43,000 licenses prostitutes in the main islands.
(c) Clandestine Prostitutes:
Such are waitresses in small drinking places (so called cafes) and tea houses, maids in Japanese style inns and low class Geishas in rural districts. This class of prostitution has become very prevalent I prefectures where licensed prostitution has been illegal – AOMORI, AKITA, GUNMA, SAITAMA and NAGASAKI.
- DISPOSAL OF THE DEAD:
About 53% of dead bodies are cremated throughout JAPAN, the rest are buried. The proportion cremated with which one or other method may be employed. In TOKYO for example where cremation is easy and burial difficult 85% of corpses are cremated.
- VENEREAL DISEASES:
Gonorrhoea, Syphilis and Chancroid are very common in JAPAN, Gonorrhoea being the most widespread. Reports on the incident of Granuloma Venereum are unreliable, the Japanese reporting this condition under the general classification, Ulceration.
The venereal disease infection rate of conscripts at initial examination is reported to be 12 per 1,000 and in the army as 20 per 1,000.
Deaths from Syphilis ad its sequelae during 1936, the latest year for which figures are available totalled 8,980.
The periodic examination of Prostitutes (legally required twice weekly) disclosed in 1938 –
This figure represents three cases of venereal infection for every prostitute registered in that year. The hospitalisation rate for prostitutes in the same year was 170%.
115 hospitals are provided for prostitutes – a capacity of 5,000 beds – a sharp commentary on the disease incidence amongst these women – one bed for every eight registered.
33 Venereal disease clinics for prostitutes were established in the major cities and in addition some 200 so called “substitute venereal disease clinics for the treatment of café waitresses etc.
In 1938 Substitute Venereal Disease clinics treated 3,095 in-patients and 10,936 out-patients. Amongst in-patients the relative frequency of the three commonest forms of venereal disease was:
Amongst out-patients incidence was:
Note: The excess over 100% represents individual treatment for more than one disease at one time.
It is apparent from these figures that an alarming proportion if not all of the women readily available to troops either as prostitutes or “pick-up” are infected with venereal disease in one or more of its forms.
- TUBERCULOSIS:
Tuberculosis in all its forms is the greatest cause of death in JAPAN (206 deaths per 100,000 population per annum).
Morbidity does not vary appreciably in different parts of the country but death rate is higher in the cities. It is estimated that the annual death rate is 150 in villages and 361 per 100,000 in cities. The pulmonary form has the highest mortality and intestinal tuberculosis the next highest – in both forms the death rate is higher in females. In 1938 there were 150,000 deaths from tuberculosis, 105,000 of these were due to pulmonary tuberculosis.
In 1938 there were 153 tuberculosis sanitoria with a total bed capacity of 14,138.
- BOWEL INFECTION:
(a) Dysentery –
Bacillary dysentery is more common than amoebic and owing to the prevalence of Shiga infection is clinically more serious than in other parts of the world. Flexner infections are common also.
Dysentery prevalence is concurrent with the warmer weather – commencing in May – June, reaching a maximum in August – September and declining in October – November.
In JAPAN as elsewhere flies play an important part in the initiation and maintenance of epidemics whilst Japanese practices in the cultivation and consumption of fresh vegetables and uncooked food provide the source of infection for a great proportion of cases.
The fatality rate throughout JAPAN averages 20% to 25% of cases in the general population and about 10% in adults. Group Mortality rates for diagnosed dysentery per 100,000 of population in the various prefectures are shown in Chart 8. It must however be recognized that the great bulk of deaths from bowel infection in persons over 2 years of age are recorded in JAPAN as due to “Diarrhoea”, a cause of death practically unknown in this age group in western countries and doubtless including a large proportion of fatalities from dysentery and salmonella infections.
The total annual death rate from bowel infections (including dysentery, typhoid and diarrhoea) is 204 per 100,000 of population and these infections cause more deaths than any other agent except tuberculosis (206 per 100,000).
In 1938 the death rates per 100,000 from bowel disease were:
(b) Enteric –
Typhoid and Paratyphoid fevers are extremely common throughout JAPAN. Incidence is especially high in late summer and early autumn. Before the war the annual notifications averaged 40,000 typhoid and 5,000 paratyphoid with, in 1938, 17% mortality rate.
These infections are particularly common in towns and it is estimated that infection is transmitted by:-
(c) Cholera –
All cases of cholera reported during recent years have been imported from CHINA. No cases were notified from 1939 to 1941 (incl). Records since 1941 are not available but the probability of importation must have been greatly enhanced under war conditions and by troop movements between JAPAN and the Asiatic mainland. Although not endemic Cholera must be regarded as an ever present risk in JAPAN.
- MOSQUITO BORNE DISEASES:
(a) B. Encephalitis
Japanese summer encephalitis is due to a specific neurotropic virus and is believed to be similar to if not identical with Russian autumn encephalitis. Its greatest prevalence is in the hotter regions of JAPAN, between 30 degrees and 40 degrees North latitude. It extends as far North as AKITA and AOMORI prefectures in the extreme North of HONSHU but is not recorded from HOKKAIDO.
The principal areas of endemicity are:-
- FUKUOKA and environs on KYUSHU.
- FUKUOKA and environs on KYUSHU.
Outbreaks have occurred in the central prefectures of HONSHU including TOKYO.
The disease has a seasonal incidence being epidemic four to seven weeks in the summer months (July – September) and disappearing in the cool weather. It is favoured by low rainfall and intense heat. There is no correlation between its incidence and the population density. Susceptibility is greatest in the elder age groups but all ages are affected. The overall mortality rate is 65% of cases ranging from 50% in children up to 10 years of age to 83% in the age group 81 to 90 years.
The virus is believed to be transmitted to man by several species of mosquitoes – C.pipiens pallens, C.tritaeniorryhynehus and Aedes togoi. Aedes albopictus may also play a part.
Distribution of cases in the 1924 epidemic is shown in Chart 1.
(b) Filariasis –
W. benerofti is the only filarial pathogen so far reported in JAPAN. Areas of endemicity are shown in Chart 3. Although the disease is Mosquito borne the divergences of its distribution from that of B.Encephalitis are quite striking suggesting that though certain species of mosquito may be capable of carrying both diseases the principal vector or vectors of each are mutually exclusive.
Figures for the incidence of filariasis are not available but in 1939, 120 deaths were certified as due to this disease. The principal vectors are C.quinquefasciatus (fatigans) and A.hyrcanus.
Other species in which development of the filarial parasites has been demonstrated are:-
(i) A.albolateralis, A.koreicus and A.togoi.
In A.albopictus, A.flavipictus and A.galloisi development is arrested.
Suitability of A.alboscutellatus and A.japonicus as vectors is doubtful.
(ii) Culex Group – C.tipuiformis and C.sinensis
(c) Dengue –
Dengue is normally rare in JAPAN but the vector A.albopictus is widespread and numerous so that epidemics must be regarded as potential and understood to depend upon the introduction of infection and the continuance of a sufficiently high mean temperature, for an adequate period.
Since 1942 several outbreaks have been reported in ports following the return of troops from overseas – NAGOYA, KOBE and OSAKA. In the course of an epidemic in KYUSHU and SW HONSHU, 13,000 cases were notified. Owing to the normal rarity of the disease in JAPAN it is probably that a considerable proportion, particularly of early cases, remained unrecognised or unreported.
A.aeyupti, the dengue vector of the Australian region, has been reported only occasionally in JAPAN. It is common in the RYUKUS and it is probably that the specimens identified on the home islands were in fact importations.
(d) Malaria –
Under normal conditions Malaria is not a serious problem and is not notifiable. The prevailing form is BT, cases occurring in the spring and summer with a recurrent peak, probably due to relapses, in the winter months. Only isolated quartan infections have been reported and the few MT notifications have been chiefly among Koreans. It is of interest to note that many Koreans are drug addicts ad that cases amongst them are alleged to have occurred following the use of infected hypodermic needles.
The incidence is highest in Southern prefectures – low lying damp districts favouring the breeding of A.hyrcanus sineansis. The disease not being notifiable, no satisfactory surveys have been made and morbidity statistics are not available. Before 1937 from 50 to 75 deaths were reported annually. Of these 50% were reported from OKINAWA whilst those on the home islands were principally amongst Koreans and repatriated troops.
It must be realized that the Malaria position may change under wartime conditions. Un-confirmed reports for 1934 suggest that there has been considerable Malaria brought to the home islands by troops from the Pacific.
- TYPHUS:
(a) Tsutsugamashi (Mite or Scrub Typhus) is endemic along certain rivers in the mountain districts and plains of NIIGATA, AKITA and YAMAGATA prefectures in NW HONSHU. Too great reliance should not be placed upon the alleged absence of the disease from other districts.
In NIIGATA prefecture foci of especially heavy infection lie along the banks of the SHINANOGAWA, AKAWA, HAYGEGAWA and UONUMAGAWA river.
In AKITA prefecture the principal endemic areas lie along the MONIGAWA, MINASEGAWA, NISHIMATONAIGAWA and MASUDAGAWA rivers.
In YAMAGATA prefecture along the banks of the UOGAMIGAWA river.
The river banks are subject to flooding and become heavily mite infested when planted with cereals and hemp at the time of the greatest warmth and humidity. Cases commence to appear toward the end of June and cease in October in NIIGATA prefecture. In AKITA cases are confined to August and September.
The case mortality ranges from 10% to 50% with an overall average of from 25% to 30%. Severity seems to vary and the form of the disease in AKITA is believed by the Japanese to be relatively mild compared to that in NIIGATA.
Reservoirs include field values – microtus montebelli rabbits and ground squirrels. Sparrows, red thrushes, pigeons, ducks and domestic fowls have also been found to carry the vector mite Tr.akamushi.
The Japanese endeavour to reduce the endemicity by burning all grass and shrubs, sprinkling lime on the suspected area and spraying working clothes with kerosene.
(b) Epidemic Typhus –
Lice (Pediculus corporis) are widespread in their distribution throughout JAPAN. Serious outbreaks of epidemic typhus associated with famines were experienced in the last century. There was an outbreak of considerable severity in 1914 when the disease was most prevalent from March to June and spread southward from NW HONSHU to TOKYO. Since that time cases have only been sporadic. It is reported that there were 864 typhus notifications during the first six months of 1941. Under war conditions the risk of typhus outbreaks must be regarded as considerably enhanced.
(c) Endemic typhus is commonest in sea ports. Human cases are reported only occasionally but infected rates are often found around docks, warehouses and stores. This source of infection probably accounts for the sporadic cases of Typhus reported since 1923.
- SPIROCHAETAL DISEASES:
(a) Leptospirosis –
Various well known and some obscure forms of leptospirosis are reported; WEILS DISEASE due to L.icterohaemorrhagiae, HASAMI DISEASE due to L.atumnalis, SEVEN DAY FEVER (NANUKAYAMI) due to L.hebdomadis.
Infection is transmitted by contamination of food or water by the urine of infected rates and the leptospirae may gain entry to the body either by oral ingestion or by percutaneous transit during bathing and wading.
WEILS DISEASE has a seasonal prevalence in summer and autumn occurring chiefly from July to November but rarely during the winter.
The particular areas of endemicity are shown in Chart 5.
(i) In HONSHU, the prefectures of CHIBA, SHIZUOKA, GIFU and TOYAMA.
(ii) In SHIKOKU, the prefectures washed by the Inland Sea.
(iii) In KYUSHU the prefectures of FUKUOKA, SAGA, NAGASAKI and KUMAMOTO.
HASAMI DISEASE resembles WEILS DISEASE but occurs chiefly in SHIZUUOKA prefecture.
SEVEN DAY FEVER occurs in summer chiefly in KYUSHU but also occasionally in central JAPAN. It may assume the proportions and characters of an epidemic.
(b) Rat Bite Fever (Sodoku) –
There are two aetiological forms of this disease:-
- Infection by Borrelia muris (Spirillum minus). This is the commoner form.
- Infection by Str.moniliformis.
Cases are not uncommon but no statistics are available. The condition which of course is transmitted by the bite of an infected rate is said to be especially common in the prefectures of KOCHI and TOKUSHIMA on the Pacific shores of SHIKOKU.
One death was reported amongst 49 cases described in the literature from 1897 to 1909.
(c) Relapsing Fever –
Outbreaks of Relapsing Fever due to infection with Borrelia recurrentis occur. Transmission is by body louse P.cerporis.
- HEMINTHIASIS:
Worm parasitism in man is extremely common in JAPAN. In 1938 of 582,000 persons examined for belminths, 48% were found infected and in the following year 44% of 800,000 examined were shown to be carriers.
(a) Nomatodes –
Round worm infestation is very frequent throughout JAPAN –
(i) Ascaris – Of proved worm carriers, 83% in 1937 and 85% in 1938 were infested with ascaris lumbricoides.
(ii) Hookworm – The incidence of hookworm infestation varies with different areas. Of proved helminth carriers, 22% in 1937 and 22% in 1938 were infested with hookworm. The prevailing form is Ankylostona duodenale and no details are available of Necator infestation.
Hookworm was formerly particularly common in SAITANA prefecture, a rural district North of TOKYO. Here, prior to 1922, 54% of the population were affected. An intensive hookworm campaign had reduced the incidence to 24$ by 1938.
(iii) Trichinella spiralis – transmitted in JAPAN by undercooked pork – is said to be rare but is known to occur.
(b) Cestodes –
Tape worms are said to be common but are not officially recorded –
(i) Diphyllobothrium latum is the commonest form – but productive of more severe symptoms is Dipologenonorus granulis.
The parasites are transmitted to man by swallowing the spargana in the under-cooked flesh of fresh water fish.
In addition to parasitism by the adult worm man may become infected by spargana (sparganosis) by drinking polluted water.
(ii) Taenia saginata and T.solum are reported only occasionally
(iii) The dwarf tapeworms, Hymenolopis nana, H.dimunuta and H.fraterna are widespread.
H.nana has no intermediate host, the others gain entry to man by the swallowing of infected fleas in under-cooked cereals.
(c) Trematodes –
Infection by trematodes is common and widespread in JAPAN owing to the prevalent practice of eating fish, crustaceans and vegetables, raw or under-cooked and using untreated water for drinking and ablution. In 1938 of 1,000,000 persons examined throughout JAPAN, 11,000 harboured flukes. In AOMORI prefecture the infestation rate was 12%.
(i) Sehistosomiasis – Infestation with S.japenieum is fairly common in certain prefectures especially in SAGA and FUKUOKA on KYUSHU and HIROSHIMA, OKAYMA, YAMANASHI, SHIZUOKA, IBARAKI and the environs of TOKYO on HONSHU.
Chart 4 displays the localities of heavy endemicity in these prefectures and also indicates the less heavily involved prefectures from which parasitism was reported in 1937 – 38.
Distinct foci are situated:-
In the paddy fields, rivers and lakes near KIFU, in the prefecture of YAMANASHI. This is one of the most important endemic areas in JAPAN producing over ¾ of the total annual cases.
On the CHICUGO River on the border between SAGA and FUKUOKA near KURUME.
Along the ASHIRA River in the KATAYAMA district of HIROSHIMA and the neighbouring district of OKAYAMA prefecture.
About UKISHIMA in SHIZUOKA prefecture near the sea coast.
Along the lower reaches of the TOMI River in the IBARAKI prefecture NE of TOKYO.
The intermediate hosts are snails of the Genus Melania & the most important Katayama nosophera. The cercariae enter man, the definitive host whilst bathing in infected water.
(ii) Clornorchiasis – Clonorchis sinensis is one of the most widespread and important pathogenic flukes in JAPAN. The geographical distribution in the home islands is shown in Chart 6. The most important endemic areas are the prefectures of SAGA on KYUSHU and of OKAYA, HYOGO and SAITAMA on HONSHU.
The first intermediate hosts are snails of the Genus Bithynia and man is infected by the consumption of raw and imperfectly cooked fresh water fish.
(iii) Fascieia hepatica, the liver fluke is occasionally reported. Man, the definitive host is infected by eating under-cooked green vegetables, the first intermediate hosts being snails of the Genus Limnaea.
(iv) Opistherchis felineus, the cat liver fish is occasionally reported in man in JAPAN. Infection is by the ingestion of raw or undercooked fresh water fish.
(v) The intestinal flukes are of less importance pathologically then are the Liver flukes.
Metagonimus yokogawa, Heterophyes heterophyes, and Fasciolopisis buski are common.
The whole of JAPAN is involved but IBARAKI, YAMANASHI, SHIZUOKA, OKAYAMA, HIROSHIMA and SAGA are particularly affected.
Metagonimus and Heterophes gain access to the body of man following consumption of improperly cooked or salted, fresh water or brackish water fish. Snails of the Genus Melania serve as the first intermediate hosts.
F.buski reaches man by the consumption of raw pods, roots, stems and bulbs f fresh water plants used in the Japan dietary. Snails of the Genus Planorbis serve as the first intermediate host.
(vi) Paragonimus westermanni, the oriental lung fluke is an important pathogen, causing a pulmonary infection resembling tuberculosis, with infiltration abscess formation, cough, haemophysis, emaciation and possibly death.
Incidence figures are not available but foci of infection occur wherever snails of Genus Melania – the first intermediate host – are found in conjunction with certain crabs and crayfish – the second intermediate hosts – which are pickled with rice and eaten raw.
Endemicity is maintained by reservoirs – cats, dogs and rodents.
- ANIMAL DISEASES TRANSMITTED TO MAN
(a) Anthrax
A few sporadic cases are reported each year.
(b) Actinomycosis –
Occurs but is rare.
(c) Brucellosis –
10% to 20% of Japanese cattle carry B.abortus. The incidence of Undulant Fever in the population is however uncertain – it is likely to be found in most parts of JAPAN.
(d) Foot and Mouth disease-
Epidemic stomatitis, epizootic aphthae due to filtrable virus is known to occur.
(e) Glanders –
Human cases occur occasionally. There are no reliable reports and the disease is not of great importance in human pathology.
(f) Tularaemia –
Rabbit fever occurs occasionally in all parts of JAPAN where it is known as CHARA’s disease. The disease is due to infection with P.tularense conveyed to man by ticks or mechanically by Tabanid flies. No reliable reports on the incidence of Tularaemia in man are available but Tabanid flies are for the most part confined to the Northern end of HONSHU and to the island of HOKKAIDO. Ticks, the particular vectors of Tularaemis occur throughout JAPAN.
(g) Rabies –
The incidence of rabies is remarkably low as a result of energetic control. In 1935, 6 Rabid dogs were reported, 4 in TOKYO and 2 in HYOGO.
(h) Tetanus –
Tetanus occurs sporadically throughout JAPAN.
- KALA AZAR:
Leishmaniasis is very rare. Such cases as do occur are believed to be imported from CHINA.
- LEPROSY:
Leprosy is widely distributed. Cases are estimated to total some 35,000 to 50,000.
- LETHARGIC ENCEPHALITIS:
A number of cases of A.encephalitis are reported each year. There were 955 cases with 614 deaths in 1938 (TOKYO 160 cases, with 126 deaths). There is possibly confusion of diagnosis between A.encephalitis and B.encephalitis in some areas.
- SMALL POX:
Compulsory vaccination is the law in JAPAN. Vaccination must be effected within 6 months of birth and re-vaccination during the tenth year. Occasionally cases still occur in 1938, six, in 1939, twenty six, and in 1940, seventy four deaths were recorded. Occurrence of cases is attributed to failure of the population in certain areas to comply with vaccination law. Nomads living on boats and barges are in particularly likely to be overlooked by the public vaccinators.
- TRACHOMA:
Trachoma is very common throughout JAPAN. In 1938, 8% of 6,500,000 persons examined were found affected. Incidence in conscripts at initial is stated to be 15%.
Distribution is not uniform. It is high in AOMORI, MIYAGI, GUNMA, NARA, KAGAWA and KUMAMOTO. It is law in NAGANO and TOYOMA.ENVIRONMENTAL DISEASES:
21. ENVIRONMENTAL DISEASES
(a) Skin –
Impetigo, Scabies and Mycotic infections are very common throughout JAPAN. Miliaria is not a problem. A contact dermatitis due to the toxin of the heath Paedarus idea occurs in rural districts.
(b) Trench foot and Frost Bite –
Are likely to occur especially in HOKKAIDO and in the mountains of HONSHU which are characterized by a long and severe winter.
- PEST AND INSECT VECTORS OF DISEASE:
MOSQUITOES –
(a) Anopheline are present through the whole year in Southern JAPAN but are far less numerous in winter than in the warmer weather so that mosquito borne disease are mainly aestival.
An.hyrcanus sniensis is by far the most important vector of BT malaria, and also carries filariasis. This species breeds in open country in clear water swamps and rice fields.
An.lindesayi japenicus is a possible but probably weak vector of malaria. It breeds in the clear pools of rocky stream beds. It is an outdoor feeder and bites during the evening hours.
An.indesayi japenicus is a possible but probably weak vector of malaria. It breeds in the clear pools of rocky stream beds. It is an outdoor feeder and bites during the evening hours.
An.sineroiedes, An.koreicus, An.edwardsi, are common around TOKYO and occasionally reported elsewhere in the three southern islands. They do not appear to be of any significance.
(b) Aedes are essentially day biting species but not invariably so. A.togoi certainly bites also at night. All Aedes species especially togoi are considered vectors of B.encephalitis.
Aedes aeypti is rare in JAPAN but is common in RYUKUS and when occasionally found in the home islands may have been introduced.
A.alblateralis, A.kereicus and A.togoi are common and are vectors of filariasis.
A.albopicturs, A.flavopictus and A.galloisi are prevalent in the summer months. W.bancrofti has been shown to be capable of only partial development in these species.
A.albosoetellatus and A.japonicus are also found but their significance as vectors of disease is doubtful.
A.albopicturs would probably play a part in maintaining epidemic dengue, under suitable climatic conditions, if infection were introduced.
(c) Culicines are a night biting species breeding usually in dirty-or polluted water.
C.tipuliformis, C.fatigans, C.pipions pallens, C.snensis and C.tritaeniorrhynchus are found on HONSHU, KYUSHU and SHIKOKU. There are potential vectors of W.bancrofti.
C.pipiens pallens and C.tritaeniorrhypnohus are proved vectors of B.encephalitis. The others are suspected.
(d) Flies –
Flies are common but are kept under controlled by organised garbage disposal and popular fly destruction campaigns much more effectively than elsewhere in Asia.
(e) Sand flies –
Sand flies are occasionally found in JAPAN proper more particularly in Southern HONSHU, SHIKOKU and KYUSHU. They are not known as vectors od disease.
Simulium is prevalent in HOKKAIDO and has also been reported from HONSHU and KYUSHU. It is not shown to be a vector of any disease but it is irritating bites are not infrequently followed by infection and ulceration.
(f) Tabanidae –
These large biting flies are found particularly at the Northern end of HONSHU and on HOKKAIDO. Bites are painful but apart from the local lesion they are not considered important as pathogenic agents. They may however serve as mechanical vectors of tularaemia.
(g) Lice –
P.cerporis is widespread and may be a vector of epidemic typhus and relapsing fever (Borrelia recurrentis).
P. capitis (phthyrius pubis) is found only in parts of JAPAN.
(h) Ticks –
Ticks are found in all parts of the home islands. Ixedes ricunus is known and H.leporis and a Dermacentor (sp?) must be assumed to carry Tularaemia. Ticks are apparently of no significance in the transmission of other diseases.
(i) Mites-
Tr.akamushi is a vector of R.crientalis the causal agent of scrub typhus. It is a natural parasite of field mice, rates and voles. It is reported to be prevalent only along certain rivers in NIIGATA, YAMAGATA and AKITA prefectures.
Sacroeptes scabei is widely reported.
(j) Spiders and Scorpions –
No venomous species are reported.
(k) Molluscs –
Several molluscs are important as the intermediate hosts of certain parasites and flukes.
Katayama nosophera carries S.japoniem.
Snails of the Genus Malania serve as intermediate hosts for Metagonimus yokogawi and P.westermanni.
Planerbis caenosus and Segmentina schmackeri serve as intermediate hosts for F.buski.
Bithynia fushsiana, C.sinensis and Tymphonatomus microptera, brackish water snails serve as intermediate hosts for the intestinal fluke H.heterophyes.
(l) Reptiles –
The only important snake is the mamushi adder (Trigonocephalus biomheffill. This reptile has a maximum length of 2 feet, most are much smaller. It has a triangular head and its body is dark drown or earthy in colour with blackish spots on both sides of the back. It is usually found in damp places under cover by day. The bite may be fatal but as a rule the poison is not very potent.
(m) Fish –
Poisonous fish are found in wide variety, the best known being the toad fish Tetraoden maculatus known in JAPAN as Fugu. The flesh and internal organs especially the liver contain an alkaloid, which is tasteless and odourless, is not destroyed by cooking and is rapidly fatal to man even in small quantities.
(n) Rats –
Rats are important as the hosts of insects carrying plagues, endemic typhus, tsutsutamushi fever and tularaemia. By infection of food or water their excreta, they convey salmonella infections and leptospirosis. The bite of the rate may be followed by rat bite fever (sodoku) caused by Borrelia muris or streptobacillus moniliformis. Rats harbour the dwarf tape worm hymenolepis diminuta (transmissible to man in the body of rat flea) and the worm trichinella spiralis.
Rats are ubiquitous and their prevalence in the haunts of man is favoured by the method of house construction in JAPAN, which permits them to nest between the floor and the ground or between the ceiling and the roof of wooden houses.
(o) Bears –
Two species of bears are found in JAPAN – a small species in the sparsely inhabited mountain regions of HONSHU and a large species in the deserted parts of HOKKAIDO. Either might be dangerous to man.