Corrigendum: Comparing copromicroscopy to intestinal scraping to monitor red fox intestinal helminths with zoonotic and veterinary importance

[This corrects the article DOI: 10.3389/fvets.2022.1085996.].

Comparing copromicroscopy to intestinal scraping to monitor red fox intestinal helminths with zoonotic and veterinary importance

The red fox acts as reservoir for several helminthic infections which are of interest for both public and animal health. Huge efforts have been made for the assessment of the sensitivity of coprological tests for the detection of Echinococcus multilocularis, while less attention has been paid to other helminthic species. This study aimed at assessing the performance of two copromicroscopic techniques in the detection and prevalence estimation of gastrointestinal helminths in the red fox. Helminths were isolated from the small intestines of 150 red foxes from Bolzano province, Italy, with a scraping, filtration and counting technique (SFCT) and morphologically identified. Rectal contents were collected and submitted to simple flotation (FT) and, only for Taenids, a method based on the concentration of eggs and identification with multiplex PCR (CMPCR). Using SFCT as a reference standard, we estimated the sensitivity of the copromicroscopic tests. Three species of nematodes (namely, Toxocara canis, Uncinaria stenocephala and Pterygodermatites sp.) and five species of cestodes (E. multilocularis, Taenia crassiceps, T. polycantha, Hydatigera taeniaeformis, Mesocestoides sp.) were identified with SFCT, whereas eggs referable to the same taxa were detected with fecal diagnostics, except for Pterygodermatites sp. and Mesocestoides sp. The sensitivity of FT was low for all taxa, ranging from 9.8 to 36.3%, with lower values for Taeniidae. CMPCR was confirmed to perform better for the detection of Taeniidae eggs (23.5%) and the multiplex PCR on retrieved eggs was effective in the identification of the species. A meta-analysis of literature also suggested that our results are consistent with existing data, indicating that copromicroscopy tends to underestimate the prevalence of helminthic infections. The extent of such underestimation varies with taxon, being higher at high prevalence levels, in particular for cestodes. Irregular dynamics of egg shedding, and routine deep freezing of red fox feces may explain the frequency of false negatives with copromicroscopy. Low sensitivity of copromicroscopic tests should be accounted for when estimating prevalence and when defining the correct sample size for the detection of the parasites.

Copromicroscopic study of gastrointestinal parasites in captive mammals at Central Zoo, Lalitpur, Nepal

BACKGROUND

Zoological gardens (Zoo) provide abode to various threatened animals or trafficked animals seized by the authorities, and injured and orphaned animals. Captive animals are more susceptible to infection as they are under significant stress due to diet and space which further dwindle their resistance to parasitic infections.

OBJECTIVES

This study was conducted to determine the prevalence and burden of gastrointestinal parasites in captive mammals housed at Central Zoo.

METHODS

Fresh faecal samples from three orders of mammals including carnivora (n = 24), rodentia (n = 28) and artiodactyla (n = 35) were examined by direct smear, faecal floatation and sedimentation techniques, and the McMaster technique was applied to quantify parasite eggs per gram (EPG)/oocysts per gram (OPG) of a faecal sample.

RESULTS

One or more parasite taxa were detected in 19.54% of the examined samples and five types of GIPs including one protozoon (Eimeria spp.) and four helminths (Strongyloides spp., Haemonchus spp. and Trichostrongylus spp. and hookworm) were recorded. The protozoan prevalence (6.89 %) was lower than helminths (12.64%). The Eimeria spp. was the most prevalent parasite (6.89%) with the highest OPG (427.77 ± 25.45SD) in spotted deer (Axis axis), and the highest prevalence was noticed among artiodactyla (34.28%) followed by carnivora (12.5%) and rodentia (7.14%). Artiodactyla had both single infection (25.71%) and double (8.57%) infection. The percentage of single infection (16.09%) was found to be higher than double infection (3.44%) among the captive mammals. The wild boar (Sus scrofa) had the highest EPG of 383.33 ± 76.37SD (Strongyloides spp.), while the spotted deer had the lowest EPG of 216.66 ± 76.37SD (hookworm).

CONCLUSIONS

Despite careful management practices, the parasitic infection may be attributed to the narrow enclosure, group housing and environmental contamination. The present finding provides baseline information on the parasitic infection in captive mammals, and can be used by zoo managers for the better life of captive animals.

Comparison of coprological, immunological and molecular methods for the detection of dogs infected with Angiostrongylus vasorum before and after anthelmintic treatment

Timely diagnosis of the nematode Angiostrongylus vasorum in dogs is important in view of severe and permanent lung and cardiovascular lesions that may occur. The performance of the classical Baermann coprological method was compared with ELISAs for the serological detection of circulating antigen and specific antibodies and with Polymerase chain reaction (PCR) performed on EDTA blood, feces and tracheal swabs of serial samples from experimentally inoculated dogs over 13 weeks post inoculation (wpi) (n = 16) and following anthelmintic treatment (n = 6). Patency was observed from 6.7 to 7.6 wpi in all dogs, Baermann results were then mostly positive (116/119, 97%) during the patent period, with wide variations in the numbers of first stage larvae numbers. Blood PCR was tested positive on 1-2 occasions in 11/16 dogs in the pre-patent period, while all tested positive by antibody-detection ELISA by 6 wpi. The proportion of dogs testing positive by fecal PCR and antigen-detection ELISA rose early in the patent period. Tracheal swabs were occasionally DNA-positive in 3/16 dogs starting from 10 wpi. Following treatment, larval excretion stopped within 3 weeks and blood PCR results became negative within 1 week (5/6 dogs), while 4/6 dogs were positive for parasite DNA in tracheal swabs. Parasite antigen and specific antibodies both persisted in the blood for 3-9 weeks after treatment, with average optical densities and the proportion of positive dogs falling gradually, while results using other tests were much more variable. Results indicate that the earliest and most consistent results are obtained by the ELISAs, which can also be used for monitoring dogs after anthelmintic treatment.