Influence of Refrigeration and Formalin on the Floatability of Giardia duodenalis Cysts

Moitinho, Maria da Luz Ribeiro; Bértoli, Marta; Guedes, Terezinha Aparecida; Ferreira, Cláudio Santos

doi:10.1590/s0074-02761999000400025

Cited by 5 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, fresh fecal samples could not be used nor could they be refrigerated due to the logistical challenges. The 10% formaldehyde solution used to preserve specimens before examination may have diminished ovae and cysts floatability (40).…”

Section: Discussionmentioning

confidence: 99%

Intervention to prevent intestinal parasitic reinfections among Tarahumara indigenous schoolchildren in northern Mexico

Monárrez‐Espino

Pérez-Espejo

Vázquez-Mendoza³

et al. 2011

Rev Panam Salud Publica

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

Intervention to prevent intestinal parasitic reinfections among Tarahumara indigenous schoolchildren in northern Mexico

Monárrez‐Espino

Pérez-Espejo

Vázquez-Mendoza³

et al. 2011

Rev Panam Salud Publica

View full text Add to dashboard Cite

show abstract

“…Finally, when data collection is carried out in field sites or under extreme weather conditions, storage of samples in fixative solutions is used until analysis can be completed. However certain sample storage methods have been found to significantly distort the FEC for some internal parasites ( Moitinho et al., 1999 ). In summary, accurate quantification of FEC may depend upon (1) the distribution of eggs within faecal matter; (2) time of sample collection; and (3) storage method of faecal samples.…”

Section: Introductionmentioning

confidence: 99%

A standardised faecal collection protocol for intestinal helminth egg counts in Asian elephants, Elephas maximus

Lynsdale

Santos

Hayward

et al. 2015

International Journal for Parasitology: Parasites and Wildlife

View full text Add to dashboard Cite

The quantitative assessment of parasite infection is necessary to measure, manage and reduce infection risk in both wild and captive animal populations. Traditional faecal flotation methods which aim to quantify parasite burden, such as the McMaster egg counting technique, are widely used in veterinary medicine, agricultural management and wildlife parasitology. Although many modifications to the McMaster method exist, few account for systematic variation in parasite egg output which may lead to inaccurate estimations of infection intensity through faecal egg counts (FEC). To adapt the McMaster method for use in sampling Asian elephants (Elephas maximus), we tested a number of possible sources of error regarding faecal sampling, focussing on helminth eggs and using a population of over 120 semi-captive elephants distributed across northern Myanmar. These included time of day of defecation, effects of storage in 10% formalin and 10% formol saline and variation in egg distribution between and within faecal boluses. We found no significant difference in the distribution of helminth eggs within faecal matter or for different defecation times, however, storage in formol saline and formalin significantly decreased egg recovery. This is the first study to analyse several collection and storage aspects of a widely-used traditional parasitology method for helminth parasites of E. maximus using known host individuals. We suggest that for the modified McMaster technique, a minimum of one fresh sample per elephant collected from any freshly produced bolus in the total faecal matter and at any point within a 7.5 h time period (7.30am–2.55 pm) will consistently represent parasite load. This study defines a protocol which may be used to test pre-analytic factors and effectively determine infection load in species which produce large quantities of vegetative faeces, such as non-ruminant megaherbivores.

show abstract

Interaction Forces Drive the Environmental Transmission of Pathogenic Protozoa

Dumètre

Aubert

Puech

et al. 2012

Appl Environ Microbiol

View full text Add to dashboard Cite

The protozoan parasites Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii are pathogens that are resistant to a number of environmental factors and pose significant risks to public health worldwide. Their environmental transmission is closely governed by the physicochemical properties of their cysts (Giardia) and oocysts (Cryptosporidium and Toxoplasma), allowing their transport, retention, and survival for months in water, soil, vegetables, and mollusks, which are the main reservoirs for human infection. Importantly, the cyst/oocyst wall plays a key role in that regard by exhibiting a complex polymeric coverage that determines the charge and hydrophobic characteristics of parasites' surfaces. Interaction forces between parasites and other environmental particles may be, in a first approximation, evaluated following the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. However, due to the molecular topography and nano-to microstructure of the cyst/oocyst surface, non-DVLO hydrophobic forces together with additional steric attractive and/or repulsive forces may play a pivotal role in controlling the parasite behavior when the organism is subjected to various external conditions. Here, we review several parameters that enhance or hinder the adhesion of parasites to other particles and surfaces and address the role of fast-emerging techniques for mapping the cyst/oocyst surface, e.g., by measuring its topology and the generated interaction forces at the nano-to microscale. We discuss why characterizing these interactions could be a crucial step for managing the environmental matrices at risk of microbial pollution.

show abstract

Influence of Refrigeration and Formalin on the Floatability of Giardia duodenalis Cysts

Cited by 5 publications

References 5 publications

Intervention to prevent intestinal parasitic reinfections among Tarahumara indigenous schoolchildren in northern Mexico

Intervention to prevent intestinal parasitic reinfections among Tarahumara indigenous schoolchildren in northern Mexico

A standardised faecal collection protocol for intestinal helminth egg counts in Asian elephants, Elephas maximus

Interaction Forces Drive the Environmental Transmission of Pathogenic Protozoa

Contact Info

Product

Resources

About