From: Toxocariasis: a silent threat with a progressive public health impact
Approaches | Methods | Characteristics | Targets | Advantages | Disadvantages |
---|---|---|---|---|---|
Biopsy and visual detection of the parasite | Invasive, insensitive and time-consuming | Larval sections or eggs | Widely available | Requirement of skilled technicians | |
Blood biochemical analysis | Should be considered in combination with clinical manifestations and further laboratory confirmation | Eosinophilia (average counts of 10 000 cells/mm3, approximately 1500 cells/mm3in CT, normal range in OT or CT (< 500 cells/mm3) or eosinophil cationic protein (ECP) levels (designated as > 28 mg/L) | Useful for detection of active Toxocara infections | Non-specific | |
Sandwich ELISA | Complex monoclonal antibody (MoAb) production | Circulating TES Ag | Useful for confirmation of active infection | Low sensitivity and specificity | |
Antibody detection | TES-Ag-ELISA | A standard test for VLM and OT in reference laboratories | Antibodies | Good sensitivity and specificity (70–100%) [4, 13, 14, 33]. | Research laboratory use only |
TES-Western blot (24, 28, 30 and 35Â kDa fractions of TES Ag) | Â | Several commercially available kits in enzyme immunoassay, and Western-blot test formats (ELISA NOVUM, ELISA PU and Toxocara CHEK) [4]. | Unavailable for discrimination of past and recent infection | ||
Recombinant antigens | Less cross-reactivity with antibodies from other helminth infections in endemic regions where poly-parasitism is common, in contrast to TES-Ag [14]. | Recommended as the best option for diagnosis of human toxocariasis [67, 137–139]. | |||
Nucleic acid amplification [9] | RFLP | Requires a large quantity of genomic DNA, which is not readily available for parasites of small sizes, particularly larvae and eggs | ITS-1 ITS-2 | High sensitivity and specificity; useful for species identification and quantification of parasite burden | Technically demanding, requires skilled laboratory technicians |
RAPD | Low reproducibility and specificity; cannot distinguish between eggs of T. canis and T. cati. | ||||
PCR | The risk of carry over contamination; low throughput of samples analysis | ||||
qPCR | Rapid and specific identification of T. canis and T. cati eggs in faecal and soil samples without the need for additional post-PCR manipulations | ||||
qPCR | Rapid and specific identification of T. canis and T. cati eggs in fecal and soil samples without the need for additional post-PCR manipulations | ||||
LAMP | A cheap, powerful and convenient approach for monitoring the contamination of soil with Toxocara eggs |