Detection of Trichinellosis in Pigs by Artificial Digestion and Enzyme Immunoassay

The objective of this study was to demonstrate the reliability of current and proposed methods for the inspection of swine and other species for infection with the parasite Trichinella spiralis. Five groups of pigs were infected with doses of 2500, 500, 100, 50, and 20 T. spiralis larvae to establish moderate and low-level infections. Pigs were bled periodically during the study for samples to be tested by enzyme immunoassay (EIA). At the conclusion of the study, pigs were slaughtered and tissues collected for analyses of worm burdens and for comparison of digestion testing methods. Comparisons of pooled sample digestion methods were made using inspection methods prescribed by European Union Directives and the USDA, Code of Federal Regulations. Pooled sample digestion testing using 1-g samples was effective for detecting pigs with larval densities of >10 larvae per gram (LPG) of tissue but only partially effective for pigs with infections of <3 LPG. Pooled sample digestion testing using 5-g samples detected all pigs with infection levels >1 LPG. The EIA detected all T. spiralis-infected pigs, but did not detect infections in some pigs until 49 days after inoculation. These results demonstrate that the pooled sample digestion method using a 5-g sample size is the most effective inspection method for reducing the risk of human exposure to T. spiralis in pork.

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Sensitivity of Artificial Digestion and Enzyme Immunoassay Methods of Inspection for Trichinae in Pigs

Journal of Food Protection ◽

10.4315/0362-028x-61.3.339 ◽

1998 ◽

Vol 61 (3) ◽

pp. 339-343 ◽

Cited By ~ 21

Author(s):

H. R. GAMBLE

Keyword(s):

Sample Size ◽

Enzyme Immunoassay ◽

Trichinella Spiralis ◽

Serological Testing ◽

Digestion Method ◽

Artificial Digestion ◽

Eu Directives ◽

Digestion Methods ◽

Pooled Sample ◽

The Eu

Forty-seven pigs were infected with varying doses of Trichinella spiralis and tested for evidence of infection by serology, using an enzyme immunoassay (EIA), and by artificial digestion methods. Using a 1-g sample, as prescribed in accordance with European Union (EU) directives, the sensitivity of the pooled-sample artificial digestion method was between three and five larvae per gram (LPG) of tissue. Using a 5-g sample size, in accordance with methods described in the U.S. Code of Federal Regulations, and as required for the inspection of horses exported to the EU, the sensitivity of the test was increased to approximately 1 LPG. Serological testing by EIA detected pigs with as few as 0.02 LPG, but detection times varied from 4 to 8 weeks after infection. Mean postinoculation times for detection by serology were 32 to 42 days. On the basis of these results, it is clear that digestion testing using a 5-g sample size is the only method of those tested here that is completely reliable for detection of trichinae infection at a level that will protect public health. Both digestion testing using a 1-g sample and EIA have drawbacks. However, EIA remains a highly effective tool for epidemiological purposes and for monitoring trichinae infection on the farm.

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Methods for the Detection of Trichinellosis in Horses

Journal of Food Protection ◽

10.4315/0362-028x-59.4.420 ◽

1996 ◽

Vol 59 (4) ◽

pp. 420-425 ◽

Cited By ~ 24

Author(s):

H. RAY GAMBLE ◽

ALVIN A. GAJADHAR ◽

MORSE B. SOLOMON

Keyword(s):

Enzyme Immunoassay ◽

Trichinella Spiralis ◽

Larval Density ◽

Human Health Risk ◽

Dependent Manner ◽

Sample Sizes ◽

Tissue Samples ◽

Artificial Digestion ◽

Dose Dependent ◽

Digestion Methods

Twelve horses were infected with various doses of Trichinella spiralis and then tested for infection using direct (artificial digestion) and indirect (enzyme immunoassay) methods. Horses became infected in a dose-dependent manner. Larvae accumulated preferentially in the tongue, followed by the masseter, neck, supraspinatus, trapezius, and diaphragm. At lower infection levels, the tongue harbored several times more parasites than were found in other tissues. The sensitivity of artificial digestion methods for detecting infections was directly related to sample size. One-gram samples were not reliable for detecting infection levels of <3 larvae per g (LPG). In sample sizes of 5 or 10 g the technique allowed infections as low as 1 LPG to be detected. The enzyme immunoassay (EIA) detected all infected horses; the times following infection at which horses became seropositive varied in a dose-dependent manner, but 11 of 12 horses were positive in the EIA by 4 weeks postinoculation. One horse, with a larval density in the tongue of 0.39 LPG, did not become seropositive until 7 weeks postinoculation. The results suggest that artificial digestion of horse carcasses for trichinae should concentrate on tissue samples from the tongue or masseter muscles. Sample sizes should be a minimum of 5 g using pooled-sample digestion methods to assure detection of all infections which might pose a human health risk. The EIA is a potential substitute for artificial digestion methods and could also be useful for antemortem testing and for epidemiological studies.

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Control Indicators for the Examination of Pork for Trichinella spiralis by the Acid-Pepsin Digestion Method

Journal of Food Protection ◽

10.4315/0362-028x-57.2.173 ◽

1994 ◽

Vol 57 (2) ◽

pp. 173-175

Author(s):

CONNIE D. ANDREWS ◽

DONALD W. WEBERT

Keyword(s):

Trichinella Spiralis ◽

Digestion Method ◽

Pepsin Digestion ◽

Artificial Digestion ◽

Collagen Membranes ◽

Negative Controls

Artificial digestion using an acidified pepsin solution is one of several methods of examination of meat for the presence of Trichinella spiralis larvae. Indicator devices, which serve as visible ‘positive’ and ‘negative’ Controls, have been developed for use in this digestion method. The indicators are color-coded, red and blue, modified-collagen membranes. One each of the red and blue colored membranes are added to the solution along with the sample. The digestion of the blue indicator and the retention of the red indicator are established as criteria that the process is within acceptable limits.

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Factors affecting the efficiency of pooled sample digestion for the recovery of Trichinella spiralis from muscle tissue

International Journal of Food Microbiology ◽

10.1016/s0168-1605(99)00017-3 ◽

1999 ◽

Vol 48 (1) ◽

pp. 73-78 ◽

Cited By ~ 9

Author(s):

H.R Gamble

Keyword(s):

Muscle Tissue ◽

Trichinella Spiralis ◽

Factors Affecting ◽

Sample Digestion ◽

Pooled Sample

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Trichinella detection: Identification and statistical evaluation of sources of error in the magnetic stirrer method for pooled sample digestion

Veterinary Parasitology ◽

10.1016/j.vetpar.2013.01.031 ◽

2013 ◽

Vol 194 (2-4) ◽

pp. 106-109 ◽

Cited By ~ 8

Author(s):

Katharina Riehn ◽

Dirk Hasenclever ◽

David Petroff ◽

Karsten Nöckler ◽

Anne Mayer-Scholl ◽

...

Keyword(s):

Statistical Evaluation ◽

Sample Digestion ◽

Sources Of Error ◽

Magnetic Stirrer ◽

Pooled Sample

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Larval Gnathostomes and Spargana in Chinese Edible Frogs, Hoplobatrachus rugulosus, from Myanmar: Potential Risk of Human Infection

The Korean Journal of Parasitology ◽

10.3347/kjp.2020.58.4.467 ◽

2020 ◽

Vol 58 (4) ◽

pp. 467-473

Author(s):

Jong-Yil Chai ◽

Bong-Kwang Jung ◽

Jin-Youp Ryu ◽

Hyun-Seung Kim ◽

Sung-Jong Hong ◽

...

Keyword(s):

Potential Risk ◽

Human Infection ◽

Local Market ◽

Digestion Method ◽

Artificial Digestion ◽

Potential Risks ◽

The Mean

Chinese edible frogs, Hoplobatrachus rugulosus, were examined to estimate the potential risks of human gnathostomiasis and sparganosis in Myanmar. A total of 20 frogs were purchased in a local market of Yangon and examined with naked eyes and the artificial digestion method after skin peeling in June 2018 and June 2019. Larvae of gnathostomes and Spirometra (=spargana) were detected in 15 (75.0%) and 15 (75.0%) frogs with average intensities of 10.5 and 6.3 larvae per infected frog, respectively. Gnathostome larvae were 2.75-3.80 (av. 3.30) mm long and 0.29-0.36 (0.33) mm wide. They had a characteristic head bulb with 4 rows of hooklets, a muscular long esophagus, and 2 pairs of cervical sac. The mean number of hooklets were 41, 44, 47, and 50 on the 1st, 2nd, 3rd, and 4th row, respectively. Collected spargana were actively moving, particularly with the scolex part, and have ivory-white color and variable in size. Conclusively, it has been first confirmed that Chinese edible frogs, H. rugulosus, are highly infected with larval gnathostomes and spargana in this study. Consuming these frogs is considered a potential risk of human gnathostomiasis and sparganosis in Myanmar.

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Efficiency of acid digestion procedures for geochemical analysis of tungsten mining wastes

Geochemistry Exploration Environment Analysis ◽

10.1144/geochem2021-034 ◽

2021 ◽

pp. geochem2021-034

Author(s):

Z. Han ◽

M. Edraki ◽

A. Nguyen ◽

M. Mostert

Keyword(s):

Trace Element Analysis ◽

Major Elements ◽

Critical Element ◽

Digestion Method ◽

Element Analysis ◽

Geochemical Composition ◽

Alkali Fusion ◽

Global Demand ◽

Complete Digestion ◽

Digestion Methods

Tungsten is a critical element used in the industry with increasing global demand. There are millions of tons of current and legacy mineral processing tungsten tailings worldwide that can potentially contaminate the environment and pose human health risks. These tailings could also potentially turn into valuable resources if we thoroughly characterise their geochemical composition. In this study, an innovative method was developed to achieve the complete digestion of tungsten tailings. We tested three different digestion methods (hotplate digestion, bomb digestion, and ColdBlockTM digestion) and compared the results. Additionally, an alkali fusion for major element analysis was also applied and tested. The results showed that alkali fusion is the best method for major elements analysis, while bomb digestion is the best method for tungsten and trace element analysis, but volatile chlorite loss was also observed. The hot plate digestion method for tungsten mine tailings was not recommended, because of poor recoveries of trace elements compared to the bomb digestion method. The quick and safer ColdBlockTM digestion method could be used for Bismuth (Bi), Molybdenum (Mo), and several rare earth element analyses indicated by their recoveries being close to the bomb digestion method.

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