Laboratory studies on the prevalence and cercarial rhythms of trematodes from Bulinus truncatus and Biomphalaria pfeifferi snails from Khartoum State, Sudan

Abdel Aziz M. Ahmed, Nidal A. Ibrahim, Mohamed A. Idris

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Objectives: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes' cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. Methods: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. Results: Out of 1,257 screened Bulinus truncatus, 187 (14.9%) shed four types of cercariae. The highest prevalence of natural infection (9.5%) was by schistosome cercariae followed by amphistome (2.5%), xiphidiocercariae (2.4%) and lastly by avian cercariae (0.5%). However, out of 200 screened B. pfeifferi, 22 (11%) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00-13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00-11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. Conclusion: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae.

Original languageEnglish
Pages (from-to)65-69
Number of pages5
JournalSultan Qaboos University Medical Journal
Volume6
Issue number2
Publication statusPublished - Dec 1 2006

Fingerprint

Bulinus
Biomphalaria
Cercaria
Sudan
Snails
Cross-Sectional Studies
Periodicity
Infection
Lettuce

Keywords

  • Amphistome
  • Avian
  • Biomphalaria
  • Bulinus
  • Cercarial rhythms
  • Prevalence
  • Schistosomes
  • Xiphidiocercariae

ASJC Scopus subject areas

  • Medicine(all)

Cite this

@article{082c94c6286f4dc999d6d97b8594760d,
title = "Laboratory studies on the prevalence and cercarial rhythms of trematodes from Bulinus truncatus and Biomphalaria pfeifferi snails from Khartoum State, Sudan",
abstract = "Objectives: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes' cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. Methods: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. Results: Out of 1,257 screened Bulinus truncatus, 187 (14.9{\%}) shed four types of cercariae. The highest prevalence of natural infection (9.5{\%}) was by schistosome cercariae followed by amphistome (2.5{\%}), xiphidiocercariae (2.4{\%}) and lastly by avian cercariae (0.5{\%}). However, out of 200 screened B. pfeifferi, 22 (11{\%}) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00-13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00-11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. Conclusion: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae.",
keywords = "Amphistome, Avian, Biomphalaria, Bulinus, Cercarial rhythms, Prevalence, Schistosomes, Xiphidiocercariae",
author = "Ahmed, {Abdel Aziz M.} and Ibrahim, {Nidal A.} and Idris, {Mohamed A.}",
year = "2006",
month = "12",
day = "1",
language = "English",
volume = "6",
pages = "65--69",
journal = "Sultan Qaboos University Medical Journal",
issn = "2075-051X",
publisher = "Sultan Qaboos University",
number = "2",

}

TY - JOUR

T1 - Laboratory studies on the prevalence and cercarial rhythms of trematodes from Bulinus truncatus and Biomphalaria pfeifferi snails from Khartoum State, Sudan

AU - Ahmed, Abdel Aziz M.

AU - Ibrahim, Nidal A.

AU - Idris, Mohamed A.

PY - 2006/12/1

Y1 - 2006/12/1

N2 - Objectives: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes' cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. Methods: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. Results: Out of 1,257 screened Bulinus truncatus, 187 (14.9%) shed four types of cercariae. The highest prevalence of natural infection (9.5%) was by schistosome cercariae followed by amphistome (2.5%), xiphidiocercariae (2.4%) and lastly by avian cercariae (0.5%). However, out of 200 screened B. pfeifferi, 22 (11%) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00-13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00-11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. Conclusion: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae.

AB - Objectives: (a) To determine the natural infection rate of Bulinus truncatus and Biomphalaria pfeifferi snails with trematodes' cercariae. (b) To determine the emergence and rhythmicity of cercariae. (c) To elucidate the high-risk time for man and other animals to acquire infection. Methods: Snails were collected from Dawar El Mahadi Agricultural Scheme, Khartoum State, identified in the laboratory, kept at room temperature and fed on lettuce. The snails were screened weekly for six weeks for natural infection and infected snails were kept in the dark. The swimming patterns and resting position of the freshly emerged cercariae were studied using a stereomicroscope. The rhythmicity of the different types of cercariae was studied by screening three sets of 5 naturally infected snails under fluorescent light from 07.00 to 19.00 and similar sets from 19.00 to 07.00. Results: Out of 1,257 screened Bulinus truncatus, 187 (14.9%) shed four types of cercariae. The highest prevalence of natural infection (9.5%) was by schistosome cercariae followed by amphistome (2.5%), xiphidiocercariae (2.4%) and lastly by avian cercariae (0.5%). However, out of 200 screened B. pfeifferi, 22 (11%) shed only xiphidiocercariae. The rhythmicity studies showed that the emergence of schistosome cercariae increased steadily from 07.00 to reach its peak at 11.00-13.00. The emergence rhythms of avian cercariae are similar to those of the schistosome, but with an early peak at 09.00-11.00. The xiphidiocercariae and amphistome cercariae started with high rate of emergence at 07.00. and decreased gradually to very low levels or complete disappearance, respectively, around sunset. Conclusion: Information on cercarial rhythmicity and chronobiological characteristics are thought to be useful in avoiding water contact during high-risk time of infection and may be helpful in the identification of closely related species and strains of cercariae.

KW - Amphistome

KW - Avian

KW - Biomphalaria

KW - Bulinus

KW - Cercarial rhythms

KW - Prevalence

KW - Schistosomes

KW - Xiphidiocercariae

UR - http://www.scopus.com/inward/record.url?scp=85016335618&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85016335618&partnerID=8YFLogxK

M3 - Article

VL - 6

SP - 65

EP - 69

JO - Sultan Qaboos University Medical Journal

JF - Sultan Qaboos University Medical Journal

SN - 2075-051X

IS - 2

ER -