Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil): II. Intermediate hosts

Teles, Horacio Manuel Santana; Ferreira, Cláudio Santos; Carvalho, Maria Esther de; Lima, Valquíria R. de; Zacharias, Fabiana

doi:10.1590/s0074-02762002000900009

Cited by 7 publications

(8 citation statements)

References 11 publications

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“…It was not surprising that working on tomato farms was more risky than working on rice farms even though rice fields are more frequently flooded than tomato farms. There is substantial documentation that schistosomiasis transmission in most endemic areas is seasonal [6,23] and highest at the end of the rains [24]. Consequently, working on tomato farms (which is done during the dry season) is a high risk activity.…”

Section: Discussionmentioning

confidence: 99%

Water Contact Activities and Prevalence of Schistosomiasis Infection among School-age Children in Communities along an Irrigation Scheme in Rural Northern Ghana

Anto¹

2013

J Bacteriol Parasitol

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Of the various trematodes that infect humans, schistosomes remain among the most prevalent, and the various forms of schistosomiasis still pose significant public health problems. The prevalence of schistosomiasis infection among in-school and not-in-school children resident in communities along the Tono irrigation canals in northern Ghana was determined. Stool and urine samples from random representative samples were parasitologically examined using the Kato-Katz and 10 ml urine filtration methods respectively. A total of 920 children (mean age: 11.0 yrs; range: 6-15 yrs; STD Dev: 4.6 yrs), 573 (62.3%) males and 347 (37.7%) females with 473 in-school and 447 not-in-school participated in the study. The prevalence of Schistosoma haematobium infection was 33.2% (305/920) whilst that of S. mansoni was 19.8% (95% CI: 17.3-22.5; 182/920). The overall prevalence of infection (S. haematobium plus S. mansoni) was 47.7% (439/920). Many more males (51.7%; 95% CI: 47.5-55.8) than females (41.2%; 95% CI: 36.0-46.6) were infected. Forty-six (5.0%, 46/920) children were infected with both S. haematobium and S. mansoni. There was no difference in the prevalence of infection (S. haematobium plus S. mansoni) among children in-school (48.4%; 95% CI: 43.8-53.0) and those not-in-school (46.5%; 95% CI: 41.8-51.3). There was a statistically significant difference in prevalence of infection among communities (P=0.0002); with the lowest level of infection in residents of Korania (29.9%; CI: 20.0-41.4) and the highest among those resident in Kajelo (64.9%; CI: 51.1-77.1), with significant differences in levels of water contact activities (χ 2 =6.69; P=0.04). The highest intensity of S. mansoni infection (115.6 epg) was in Bonia where the highest prevalence of blood stained stools was collected (5.5%). Overall, 2.8% (26/920; 95% CI: 1.9-4.2) of stool samples were blood stained, whilst 10% (92/920; 95% CI: 8.2-12.2) of children had haematuria. S. haematobium ova were detected in 98.9% (91/92) of blood stained urine samples. Children infected by S. mansoni were more likely to have blood stained stool (χ 2 =32.7; P<0.0001). The prevalence of schistosomiasis infection in the irrigation project site is high, adding praziquantel to albendazole and ivermectin for distribution during the annual mass drug administration for filariasis and onchocerciasis control will be an effective way of reaching all at risk groups in the Kassena-Nankana district for the control of schistosomiasis.

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Section: Discussionmentioning

confidence: 99%

Water Contact Activities and Prevalence of Schistosomiasis Infection among School-age Children in Communities along an Irrigation Scheme in Rural Northern Ghana

Anto¹

2013

J Bacteriol Parasitol

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“…A study made by Buss et al (2004) in streams of that region demonstrated that the density of macroinvertebrates were negatively influenced by spates. The influence of rainfall on (Baptista & Jurberg 1993, Ernould & Sellin 1999, Teles et al 2002. Water flow in lotic environments is the most important factor for explaining the longitudinal distribution of the snails that are the intermediate hosts of Schistosoma spp.…”

Section: Discussionmentioning

confidence: 99%

Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774)

Giovanelli

Silva

Leal

et al. 2005

Mem. Inst. Oswaldo Cruz

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“…This municipality was chosen because the area had been studied previously and because well-documented data regarding schistosomiasis transmission in this area were available. These data clearly indicated that B. tenagophila is the only species of mollusk responsible for the transmission of the disease in this area [28], [29]. Adopted control measures, such as the treatment of people infected with S. mansoni, the use of molluscicides and the performance of basic sanitation services by technicians at residences in the urban area of the municipality, have reduced the schistosomiasis prevalence to below 1%.…”

Section: Discussionmentioning

confidence: 87%

Reduced Susceptibility of a Biomphalaria tenagophila Population to Schistosoma mansoni after Introducing the Resistant Taim/RS Strain of B. tenagophila into Herivelton Martins Stream

Marques

Rosa

Maciel³

et al. 2014

PLoS ONE

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Studies performed in the last 30 years demonstrated that a strain of B. tenagophila from the Taim Biological Reserve is completely resistant to Schistosoma mansoni infection. This resistance to parasite infection is a dominant characteristic during crossbreeding with susceptible B. tenagophila strains. These experiments also identified a 350 bp molecular marker that is exclusive to the Taim strain and does not occur in other geographic strains of this snail species. The Taim strain (Taim/RS) of Biomphalaria tenagophila was bred on a large scale, physically marked and introduced into a stream in which previous malacological analyses had revealed the presence of only parasite-susceptible B. tenagophila. Samples of offspring captured 4, 11 and 14 months after the introduction of the Taim strain were examined, and the susceptibility of the snails to S. mansoni infection dropped from 38.6–26.5% to 2.1% during the 14 months after the introduction of the Taim snail strain. A significant correlation was also observed between the absence of infection and the identification of the Taim molecular marker. These results demonstrate that the genetic marker from the Taim strain was successfully introduced into the wild snail population. In addition, a significant relationship exists between the marker and resistance to infection.

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Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil): II. Intermediate hosts

Abstract: We conducted monthly snail captures in Bananal, State of São Paulo, Brazil, between March 1998 and February 2001, to

Cited by 7 publications

References 11 publications

Water Contact Activities and Prevalence of Schistosomiasis Infection among School-age Children in Communities along an Irrigation Scheme in Rural Northern Ghana

Water Contact Activities and Prevalence of Schistosomiasis Infection among School-age Children in Communities along an Irrigation Scheme in Rural Northern Ghana

Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774)

Reduced Susceptibility of a Biomphalaria tenagophila Population to Schistosoma mansoni after Introducing the Resistant Taim/RS Strain of B. tenagophila into Herivelton Martins Stream

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