Plague and the Human Flea, Tanzania

Pulex irritans fleas were more common in villages with high plague incidence

Epidemiological Observation of Cholera in Rural Kenya in 1983

Homa Bay地区病院のコレラ検査室で調べられた約17,000検体のうち再検例を除く,1,301検体が陽性者で,うち入院者788名,健康保菌者513名であった.コレラ感染率は13～19歳の男性に最も少なく,15～39歳の女性に最も高かった.流行は3月と7月にみられ,いずれも乾期の終わりで雨期に入る直前であった.月別・年齢別にみると,3月は20～39歳,7月は13～19歳に最も多くみられた.地区別にみると,KarachuonyoとKanyadaに患者は集中していた.致命率は9%と高く,発展途上国のもつ,共通の背景があるように思われた.家族内感染は161例に認められ,他は散発例であった.薬剤感受性については,1982年に多剤耐性株が若干認められたが,1983年のほとんどが耐性株であり,O/129にも耐性を示した.耐生パターンはタンザニア分離株のそれとも異なっており,コレラ菌の土着性を思わせた.この疫学調査で最も重要なことはコレラは再感染がほとんど認められないということであった。即ち,有効なワクチン開発の可能性が大であることを示唆している.More than 17,000 rectal swab specimens were examined for Vibrio cholerae Ol at Cholera Laboratory in Homa Bay District Hospital. Out of these specimens, 1,301 cases were bacteriologically cholera-positive excluding repeated specimens. The number of admitted cases and healthy carriers were 788 and 513 respectively. Infection rate of cholera was lowest in the age-group, 13-19 of male. It was highest in female of childbearing age-group (15-39). Monthly variation of cholera-positive cases showed two peaks in March and July, closely correlated with the dry season. Monthly variation of cholera by age-group also showed two peaks in March and July. The former peak was formed by the age-group of 20-39 and the latter was by 13-19. High infection rate was found in Karachuonyo and Kanyada. The mortality of the admitted cases was 9%. One hundred and sixty-one cases were thought to be caused by family contacts, however most of the others were sporadic cases. Tetracycline resistant strains were isolated in 1982 even in Kenya, though the number was small. Most of the strains isolated in 1983 were resistant to multiple antimicrobial agents as well as O/129 which is a vibriostatic agent

Chronic hepatosplenomegaly in African school children: a common but neglected morbidity associated with schistosomiasis and malaria.

Chronic hepatosplenomegaly, which is known to have a complex aetiology, is common amongst children who reside in rural areas of sub-Saharan Africa. Two of the more common infectious agents of hepatosplenomegaly amongst these children are malarial infections and schistosomiasis. The historical view of hepatosplenomegaly associated with schistosomiasis is that it is caused by gross periportal fibrosis and resulting portal hypertension. The introduction of ultrasound examinations into epidemiology studies, used in tandem with clinical examination, showed a dissociation within endemic communities between presentation with hepatosplenomegaly and ultrasound periportal fibrosis, while immuno-epidemiological studies indicate that rather than the pro-fibrotic Th2 response that is associated with periportal fibrosis, childhood hepatosplenomegaly without ultrasound-detectable fibrosis is associated with a pro-inflammatory response. Correlative analysis has shown that the pro-inflammatory response is also associated with chronic exposure to malarial infections and there is evidence of exacerbation of hepatosplenomegaly when co-exposure to malaria and schistosomiasis occurs. The common presentation with childhood hepatosplenomegaly in rural communities means that it is an important example of a multi-factorial disease and its association with severe and subtle morbidities underlies the need for well-designed public health strategies for tackling common infectious diseases in tandem rather than in isolation

O efeito da infecção por Schistosoma mansoni na morbidade infantil no Estado da Bahia, Brasil: I — Análise do nível ecológico

Esta investigação foi levada a efeito em 10 pequenas cidades do Estado da Bahia (Nordeste do Brasil), escolhidas através de um processo amostrai. O objetivo foi estudar as correlações entre as prevalências de hepatomegalia e esplenomegalia, em diferentes áreas, com a prevalência e a intensidade da infecção pelo S. mansoni nas mesmas áreas. Nossas conclusões são: a) a morbidade esquistossomótica (prevalências de hepatomegalia e esplenomegalia) foi diretamente correlacionada com a prevalência e a intensidade da infecção; b) a intensidade da infecção (medida pelo número de ovos nas fezes) mostrou ser um bom indicador do grau de morbidade, explicando a variação da morbidade entre as áreas melhor que a prevalência da infecção; c) a prevalência de esplenomegalia e o tamanho médio do fígado abaixo do rebordo costal na linha me dio-esternal são bom indicadores da prevalência e da intensidade da infecção pelo S. mansoni na comunidade. Nossas conclusões trazem a possibilidade da construção de equações de regressão definitivas entre indicadores de morbidade e indicadores de infecção, de tal forma que o valor de um possa ser usado para predizer o valor do outro

The effect of Schistosoma mansoni infection on child morbidity in the State in Bahia, Brazil: II — Analysis at the individual level

The present investigation was carried out on a sample of 840 children (5 to 16 years old) from ten small towns of the State of Bahia in northeastern Brazil. The objetive was to study, by using a cross sectional methodology, the evolution of schistosomiasis morbidity (hepatic and splenic enlargement) in children, and the role of the intensity of S. mansoni infection in this process. The children were analised in three age groups (5 to 8, to 12 and 13 to 16 years old) and classified as uninfected, mildly infected, moderately infected and heavily infected according to the number of eggs in the stool. In children aged 5 to 8 years, increasing egg counts were not associated with increasing frequencies of hepatic or splenic enlargement. In the 9 to 12 years old group and association was observed with the prevalence of hepatic enlargement, but not with the prevalence of spleen enlargement. In the oldest group, 13 to 16 years old, an association was observed with the prevalence of enlargement of both organs. It was evident that in this population schistosomiasis morbidity develops in the early period of life as a gradual process starting with liver enlargement and followed by spleen enlargement some years later. It was found that the intensity of infection has a fundamental role in this process, although there is a latent period of some years before clinical splenomegaly appears in moderate-heavily infected children. The Authors suggest that the prevalence of splenomegaly in the 13 to 16 years old group is a good measure of the community level of schistosomiasis morbidity and could be used to measure the impact of control programs

ケニア諸地域住民の腸管寄生原虫感染状況

1980年5月から11月の間にケニアのNaivasha，Kitui，M achakos，Taveta及びNandi Hillsの住民2,114人から採取した糞便についてホルマリン・エーテル法により腸管寄生原虫のシストの検査を行い感染状況を調査した。その結果，赤痢アメーパは31.8%， 大腸アメーパは52.3%と極めて高率を示し，その他は小形アメーパ4.8%，ヨードアメーパ8.7%，ランブル鞭毛虫8.3%，メニール鞭毛虫10.4%であった。腸トリコモナス及びEntamoeba hartmanniも少数例検出されたが，大腸パランチジウムやイソスポーラなどは検出されなかった。総陽性率(陽性総数/検査総数)は75.1%にも及び，飲料水，食物など生活環境が糞便によって高度に汚染されていることが示唆された。陽性率に男女聞の有意差は認められなかった。年齢別にみると，4歳以下の乳幼児でもすでにかなり高率に感染がみられるが，ランプノレ鞭毛虫を除き，特に30歳代から40歳代で最高値を示した。ランプル鞭毛虫は若年齢層ほど高い陽性率を示し4歳以下が最高であった。本調査は日本国際協力事業団(JICA)の医療協力「ケニア伝染病研究対策プロジェクト」の一環として行われたものであり，その撲滅対策を，戦後日本で実施され成果をあげた寄生虫予防対策事業との関連において考察した。During the period from May to November in 1980, a total of 2,114 stool specimens were collected from individuals living in Naivasha, Kitui, Machakos, Taveta and Nandi Hills areas in Kenya, and they were examined for intestinal protozoa by formol-ether concentration method followed by idoine-staining. Out of 2,114 specimens 673 (31.8%) were positive for Entamoeba histolytica, 1,105 (52.3%) for Entamoeba coli, 102 (4.8%) for Endolimax nana, 184 (8.7%) for Iodamoeba butschlii, 176 (8.3%) for Giardia lamblia, and 220 (10.4%) for Chilomastix mesnili. The total positive rate, which means the percentage of positive persons for any kinds of intestinal protozoa, was 75.1 per cent