Development of a New LAMP Assay for the Detection of Ancylostoma caninum DNA (Copro-LAMPAc) in Dog Fecal Samples

Identification of Ancylostoma caninum in Domestic Dogs from Ecuador via Various Techniques

BACKGROUND Ancylostoma caninum is a soil-borne, soil-transmitted helminth with infective larvae and produces cutaneous larva migrans in humans. The objective of this study was to confirm the presence of A. caninum in domestic dogs from the urban-marginal and rural sectors of the Ecuadorian coast through morphometry, culture, and molecular techniques. MATERIAL AND METHODS A total of 498 domestic dogs were analyzed via 5 coproparasitic screening methods: direct, modified flotation, sedimentation with centrifugation using saline solution (identification of eggs), and modified Baermann and Harada-Mori methods (identification of larvae). For confirmation, culture (agar in plates, Müller-Hinton agar plates, MacConkey agar plates, and artisanal media with sand and/or ravine soil, both sterile, and all prepared in Petri dishes), polymerase chain reaction (PCR), and DNA sequencing analyses were subsequently conducted via morphometric methods. RESULTS A total of 250 domestic dogs were diagnosed with A. caninum (50.20%) via coproparasitic methods. The parasite was subsequently confirmed via morphometry, cultured in 5 culture media, and detected by PCR, and phylogenetic characterization was performed. CONCLUSIONS The coproparasitic methods used for screening increased the sensitivity of the results. Morphometry is an easily accessible and low-cost confirmatory method. The culture method was used to test the good adaptability of and infection by the parasite. The presence of A. caninum was detected for the first time via PCR, and its phylogenetic profile was analyzed using the molecular marker cox1.

Comparison of three LAMP protocols for the simultaneous detection of DNA from species that produce cystic echinococcosis

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by species of the Echinococcus granulosus sensu lato complex. Different types of canids may act as definitive hosts by eating raw viscera infected with fertile hydatid cysts. The intermediate host (mainly ungulates) and humans acquire the infection through the fecal oral route (i.e. egg ingestion). Globally, more than 1 million people are affected by CE, causing a loss of 1-3 million disability-adjusted life years (DALYs) and a financial burden of US$ 3 billion annually. Loop mediated isothermal amplification (LAMP) protocols promise to be a useful tool to detect DNA, providing a low cost and thermocycle-free methodology. Given that surveillance for CE can be performed in feces from canids or other environmental matrixes contaminated with eggs, the characteristics of a LAMP protocol would favor implementation in endemic areas with basic resources. Herein, we compared three LAMP protocols for the simultaneous detection of E. granulosus s.l. species that cause CE. This comparation was carried with DNA obtained from different stages of E. granulosus s.l. Two of these are newly developed protocols that showed good analytical sensitivity and specificity. In both cases, the use of malachite green dye to directly visualize the test result was possible. From these two new LAMP protocols, one had better values for the detection of DNA from different types of E. granulosus s.l. DNA samples. Therefore, through this study, we provide a low-cost new tool for DNA detection of E. granulosus s.l. in poorly equipped laboratories from endemic areas.

Advances in diagnosis of gastrointestinal nematodes in livestock and companion animals

Diagnosis of gastrointestinal nematodes in livestock and companion animals has been neglected for years and there has been an historical underinvestment in the development and improvement of diagnostic tools, undermining the undoubted utility of surveillance and control programmes. However, a new impetus by the scientific community and the quickening pace of technological innovations, are promoting a renaissance of interest in developing diagnostic capacity for nematode infections in veterinary parasitology. A cross-cutting priority for diagnostic tools is the development of pen-side tests and associated decision support tools that rapidly inform on the levels of infection and morbidity. This includes development of scalable, parasite detection using artificial intelligence for automated counting of parasitic elements and research towards establishing biomarkers using innovative molecular and proteomic methods. The aim of this review is to assess the state-of-the-art in the diagnosis of helminth infections in livestock and companion animals and presents the current advances of diagnostic methods for intestinal parasites harnessing (i) automated methods for copromicroscopy based on artificial intelligence, (ii) immunodiagnosis, and (iii) molecular- and proteome-based approaches. Regardless of the method used, multiple factors need to be considered before diagnostics test results can be interpreted in terms of control decisions. Guidelines on how to apply diagnostics and how to interpret test results in different animal species are increasingly requested and some were recently made available in veterinary parasitology for the different domestic species.

A Comparison of Copromicroscopic and Molecular Methods for the Diagnosis of Cat Aelurostrongylosis

Simple Summary

Feline aelurostrongylosis is a worldwide distributed parasitic disease of domestic cats caused by the nematode Aelurostrongylus abstrusus. Cats may have a subclinical infection with this parasite or may show signs that overlap with those of many other respiratory conditions of cats, either parasitic or not. The diagnosis of feline aelurostrongylosis currently relies on fecal examinations, though this approach has some limits that can be overcome by innovative molecular techniques. Therefore, the present study has investigated the diagnostic reliability of a PCR assay performed on different samples collected from cats from Italy and Greece. The results of the study confirmed that PCR is highly sensitive and specific for the diagnosis of A. abstrusus infections in domestic cats.

Abstract

The gold standard method for the diagnosis of cat aelurostrongylosis is the detection of Aelurostrongylus abstrusus first stage larvae with the Baermann’s examination. Nevertheless, molecular assays have shown higher diagnostic performances compared to copromicroscopy. This study evaluated the usefulness of an A. abstrusus species-specific PCR on different biological samples collected in clinical settings from 100 privately-owned cats in Italy (n. 60) and Greece (n. 40). A fecal sample was collected from each animal and a pharyngeal swab was also obtained for cats from Italy. All stool samples were subjected to flotation and Baermann’s test. The cats were categorized in three groups based on the results of copromicroscopy, i.e., Group A (n. 50 cats with A. abstrusus infection regardless of positivity for other helminths), Group B (n. 25 cats negative for A. abstrusus but positive for at least one of any other helminth), Group C (n. 25 cats negative for any helminth). DNA was extracted from individual aliquots of feces, flotation supernatant, Baermann’s sediment and the pharyngeal swab and then subjected to a PCR specific for A. abstrusus. At least one fecal aliquot or the pharyngeal swab scored positive by the A. abstrusus-specific PCR for 48/50 (96%) cats enrolled in Group A; in particular, 38/50 (76%), 35/50 (70%), 41/50 (82%) and 21/25 (84%) DNA extracts from feces, flotation supernatant, Baermann’s sediment and pharyngeal swabs were positive by PCR. These results confirm that molecular tools are highly sensitive and specific and indicate that pharyngeal swabs are the most suitable sample for molecular analysis in clinical settings.