A comparison of modifications of the McMaster method for the enumeration of Ascaris suum eggs in pig faecal samples

Bayesian estimation of the sensitivity and specificity of coprological and serological diagnostic tests for the detection of Ascaris suum infection on pig farms

Coprological and serological diagnostic tests were compared to define the status of a pig farm with regard to Ascaris suum. On each of the 100 farms in France visited for the study, 10 blood samples were taken from pigs at the end of fattening (at least 22 weeks old) and 20 to 30 faecal samples were taken, depending on the category of animals present on the farm (10 sows, 10 piglets aged 10 to 12 weeks and 10 pigs at the end of fattening, aged at least 22 weeks). A SERASCA® ELISA test (Laboratory of Parasitology, Ghent University) was performed on each blood sample (cut-off 0.5) and a coprological analysis on each faecal sample. A Bayesian approach was used to estimate the sensitivity and specificity of the coprological and serological tests. A farm was considered positive if at least one A. suum egg was observed in the faecal samples. With regard to the serological test, various hypotheses were tested in order to define the number of seropositive animals required to consider a farm positive for A. suum. The coprological test has very good specificity in the search for A. suum, whether 20 or 30 samples are taken per farm. However, even with an increase in the number of samples, the sensitivity of this diagnostic approach is very low (less than 30%). On the other hand, the serological diagnostic method, which consists of taking blood samples from 10 animals at the end of fattening, has good sensitivity and seems better suited to defining the status of a farm with regard to A. suum, provided that a farm is considered seropositive only if two out of 10 samples are positive.

Rescue and rehabilitation of maned wolf (Chrysocyon brachyurus) in Paraguay: Case description

The maned wolf, Chrysocyon brachyurus, is the largest South American canid, with a natural distribution that stretches across Peru, Bolivia, Brazil, Argentina, Paraguay and Uruguay. The present study reports the case of a rescued specimen of maned wolf that underwent a rehabilitation process in Paraguay, starting in October 2020 with its rescue, and finalising in May 2021 with the reintroduction. Herein, we document findings regarding the general management, biometrics, feeding and environmental enrichment; chemical immobilisation and monitoring; haematology, blood biochemistry and specific serology-relevant pathogens; skin examination and bone marrow cytology; orthopaedic, ophthalmological and dental evaluation; abdominal and cardiac ultrasonography; radiology and copro-parasitology. Main findings include the feeding habits of the individual and enrichment opportunities. The animal weighed 7 kg on arrival, with an estimated age of 5 months, and 18 kg on reintroduction, with an estimated age of 1 year. The animal tested negative to serologic tests for Brucella canis, Dirofilaria, canine distemper, Toxoplasmosis and canine parvovirus. Leptospira testing showed antibodies against L. grippotyphosa on both samplings, L. wolffi and L. ictero on the first sampling, and L. pomona on the second sampling. Abdominal organs were examined and measured through ultrasound evaluation and kidneys showed no alterations. Echocardiography showed preserved mitral, tricuspid and aortic valve flows, but turbulent pulmonary valve flow. Copro-parasitology reported the presence of Lagochilascaris sp. and Balantidium sp. All the information gathered aided in diagnosing the health status of the individual, and the response to environmental enrichment helped assess the behaviour, which led to the suggestion of reintroducing the animal. These data constitute the first published health check of a maned wolf in Paraguay, which can contribute to the species' conservation in the country. The protocol presented in this study can serve as a basis for developing an action plan for the maned wolf in Paraguay.

Prevalence and risk factors associated with Toxocara canis in dogs and humans in Egypt: A comparative approach

BACKGROUND

Dogs are the most popular pet animals worldwide, and their frequent and close contact with humans poses an increased risk of zoonotic parasite transmission. Toxocara canis infection is a highly pervasive and economically significant zoonotic infection transmitted by dogs worldwide, commonly in tropical and subtropical regions, particularly in developing countries.

OBJECTIVES

This study evaluates the epidemiological profile and associated risk factors of T. canis exposure among humans and T. canis infection in domestic dogs in two climatically different governorates in Egypt.

METHODS

Faecal samples from 360 domiciled dogs were examined using the flotation technique to detect T. canis eggs. In addition, 276 human serum samples were evaluated by enzyme-linked immunosorbent assay over a period of 10 months from May 2021 to February 2022 in the Alexandria and Qena Governorates, Egypt.

RESULTS

Shedding of T. canis was identified in 33.33% (120/360) of dogs and the overall seroprevalence in the human population was 20.65% (57/276). Lower Egypt, represented by the Alexandria Governorate, had higher canine infection (39.47%) and human seropositivity (29.87%) rates than those of Upper Egypt, represented by Qena Governorate (26.47% and 9.02% in dogs and humans, respectively). Statistical analysis of the sociodemographic characteristics of the participants revealed that handwashing, washing of vegetables and fruits and sex were associated with human T. canis exposure.

CONCLUSION

The prevalence rates of confirmed T. canis infection in the Egyptian dogs population and the associated human seropositivity rates reflect its importance as a public health concern and support the call to increase public awareness of this issue. The risk factors identified in this study can contribute to the development of more effective control and prevention strategies.

Comparison of ovine faecal Strongyle egg counts from an accredited laboratory and a rapid, on-site parasite diagnostic system utilising a smartphone app and machine learning

Traditional treatment for gastrointestinal helminths in grazing livestock often involves untargeted, metaphylactic blanket treatment of animals with anthelmintics. As a result, resistance to anthelmintic drugs has become a significant issue for farmers and veterinarians worldwide, impacting farm profitability and animal welfare. Faecal egg counts (FECs) are an important diagnostic test to combat further anthelmintic resistance as they enable practitioners to better distinguish between animals that require treatment and those that do not. FECs are labour-intensive, time-consuming and require trained personnel to process the samples and visually identify the parasite eggs. Consequently, the time between sample collection, transport, analysis, results, and treatment can take days. This study aimed to evaluate a rapid, on-site parasite diagnostic system utilising a smartphone app and machine learning in terms of its capability to provide reliable egg counts while decreasing the turnaround time for results associated with outsourcing the analysis. A total of 105 ovine faecal samples were collected. Each sample was homogenised and split equally between two containers. One container per sample was processed using the on-site, app-based system, the second container was sent to an accredited laboratory. Strongyle egg counts were conducted via video footage of samples by the system's machine learning (ML) and a trained technician (MT) and via microscopic examination by an independent laboratory technician (LAB). Results were statistically analysed using a generalised linear model using SAS® (Version 9.4) software. The ratio of means was used to determine non-inferiority of the ML results compared to the LAB results. Both system egg counts (ML and MT) were higher (p < 0.0001) compared to those obtained from the laboratory (LAB). There was no statistically significant difference between the ML and MT counts. The app-based system utilising machine learning has been found to be non-inferior to the accredited laboratory at quantifying Strongyle eggs in ovine faecal samples. With its quick result turnaround, low outlay cost and reusable components, this portable diagnostic system can help veterinarians to increase their testing capacity, perform on-farm testing and deliver faster and more targeted parasite treatment to combat anthelmintic resistance.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guideline for diagnosing anthelmintic resistance using the faecal egg count reduction test in ruminants, horses and swine

The faecal egg count reduction test (FECRT) remains the method of choice for establishing the efficacy of anthelmintic compounds in the field, including the diagnosis of anthelmintic resistance. We present a guideline for improving the standardization and performance of the FECRT that has four sections. In the first section, we address the major issues relevant to experimental design, choice of faecal egg count (FEC) method, statistical analysis, and interpretation of the FECRT results. In the second section, we make a series of general recommendations that are applicable across all animals addressed in this guideline. In the third section, we provide separate guidance details for cattle, small ruminants (sheep and goats), horses and pigs to address the issues that are specific to the different animal types. Finally, we provide overviews of the specific details required to conduct an FECRT for each of the different host species. To address the issues of statistical power vs. practicality, we also provide two separate options for each animal species; (i) a version designed to detect small changes in efficacy that is intended for use in scientific studies, and (ii) a less resource-intensive version intended for routine use by veterinarians and livestock owners to detect larger changes in efficacy. Compared to the previous FECRT recommendations, four important differences are noted. First, it is now generally recommended to perform the FECRT based on pre- and post-treatment FEC of the same animals (paired study design), rather than on post-treatment FEC of both treated and untreated (control) animals (unpaired study design). Second, instead of requiring a minimum mean FEC (expressed in eggs per gram (EPG)) of the group to be tested, the new requirement is for a minimum total number of eggs to be counted under the microscope (cumulative number of eggs counted before the application of a conversion factor). Third, we provide flexibility in the required size of the treatment group by presenting three separate options that depend on the (expected) number of eggs counted. Finally, these guidelines address all major livestock species, and the thresholds for defining reduced efficacy are adapted and aligned to host species, anthelmintic drug and parasite species. In conclusion, these new guidelines provide improved methodology and standardization of the FECRT for all major livestock species.

Veterinary monitoring of gastrointestinal parasites in European bison, Bison bonasus designated for translocation: Comparison of two coprological methods

It is important to monitor the level of parasitic loads in herds of European bison and to identify threats early enough to prevent their spread to other populations or species. The aim of the present study was to compare the detection sensitivity of two fecal flotation techniques, viz. the modified Willis method (WM) with centrifugation and modified McMaster flotation technique (MM), in the diagnostics of gastrointestinal parasites of European bison before the translocation of animals.

Out of 166 feces samples, Eimeria spp. oocysts (84.3% in WM and 71.1% in MM) and Trichostrongylidae eggs (82.5% in WM and 53.6% in MM) predominated. These were accompanied by eggs from Capillaria spp. (prevalence: 13.9% in WM and 3.61% in MM), Nematodirus spp. (prevalence: 18.1% in WM and 4.8% in MM) and Trichuris spp. (prevalence: 12.7% in WM and MM) were identified. The lowest prevalence was noted for cestode eggs of Moniezia spp. (5.4% in WM and 3.0% in MM).

The Willis method yielded a higher prevalence of eggs and oocysts than the modified McMaster method, and hence has a higher probability of detecting parasitic structures than the modified McMaster method, especially in cases of very low levels of invasion.

As the two methods yield consistent results, it is recommended to use the Willis method for diagnosis of internal parasite infection in European bison. This test offers more sensitive method than McMaster technique of detecting the presence of low levels of a variety of parasite eggs and oocysts in feces, while also being inexpensive and adaptable to field work.

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Methods yield similar relative prevalence.

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Higher prevalence of eggs/oocysts in Willis than McMaster.

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Very low prevalence may not be detected by the McMaster method.

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Proposed formulas are provided for converting prevalence between methods.

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The Willis method is recommended over the McMaster method.

Prevalence and Risk Factors of Bovine and Ovine Lungworm Infection at Durame District, Southern Ethiopia

Background

Lungworms are parasitic nematodes of the order Strongylidae that infect the lungs of cattle and sheep and cause bronchitis or pneumonia.

Methods

An abattoir-based cross-sectional study was conducted from November 2018 to April 2019 to determine the comparative prevalence and the possible risk factors of lungworm infection in sheep and cattle of Durame district of Kembata Tembaro zone. For this purpose, a total of 410 animals (209 sheep and 201 cattle) were randomly selected and examined for the presence of different lungworm species using the modified Baermann technique and postmortem examination. The sensitivity and specificity of fecal sample test considering necropsy as reference/gold standard was conducted.

Results

Accordingly, the overall prevalence of lungworm infection in sheep and cattle was 24.39%. Dictyocaulus filaria and D. viviparous were the only species of lungworm identified in sheep and cattle with a respective prevalence of 44.02% and 3.98%. Putative risk factors such as species and poor body condition have a significant association (p < 0.05) with the occurrence of lungworms in sheep and cattle. The lungworm infection was higher in the young age group (25.30%) and poor body conditioned (32.14%) animals. Season-wise prevalence revealed that a higher lungworm infection was recorded during autumn (32.14%) as compared to winter (22.81%) and spring (16.2%). Most of the sheep and cattle in the current study were heavily (45.0%) and moderately (39.0%) infected with lungworms whereas the rest 16.0% were infected with a low degree of lungworm infection. The specificity, sensitivity, PPV, and NPV of the modified Baermann technique against the gold standard test were 89.4%, 42%, 56.0%, and 82.7%, respectively.

Conclusion

The study revealed that lungworm infection is prevalent in sheep and cattle of the study area and that was commonly occurs during autumn and affects poorly conditioned sheep and cattle. Thus, routine and strategic deworming for the control and prevention of lungworms in domestic animals should be recommended to overwhelm the prevalence of lungworm infection.

Comparison between methods for measuring fecal egg count and estimating genetic parameters for gastrointestinal parasite resistance traits in sheep

Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to evaluate the difference in means and variances between two fecal egg counting methods used in sheep-the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); to estimate variance components for the two FEC methods, treating them as two different traits; and to integrate FEC data from the two different methods and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. Fecal samples were collected from a commercial Rideau-Arcott sheep farm in Ontario. Fecal egg counting was performed using both LMMR and the LTCM methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA), body condition score (BCS), and body weight (WT). The two FEC methods were highly genetically (0.94) and phenotypically (0.88) correlated. However, the mean and variance between the two FEC methods were significantly different (P < 0.0001). Therefore, re-scaling is required prior to integrating data from the different methods. For the multiple trait analysis, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with re-standardized LTCM records converted to the same mean and variance of LMMR. Heritability estimates were 0.12 ± 0.04, 0.07 ± 0.05, 0.17 ± 0.06, and 0.24 ± 0.07 for LFEC egg count, FAMACHA, BCS, and WT, respectively. The estimated genetic correlations between FEC and the other parasite resistance traits were low and not significant (P > 0.05) for FAMACHA (r = 0.24 ± 0.32) and WT (r = 0.22 ± 0.19), and essentially zero for BCS (r = -0.03 ± 0.25), suggesting little to no benefit of using such traits as indicators for LFEC.

Comparison of the Modified McMaster and Mini-FLOTAC methods for the enumeration of nematode eggs in egg spiked and naturally infected chicken excreta

Excreta egg counting techniques are used for indirectly estimating the magnitude of gastrointestinal nematode infection in live animals. The aim of this study was to optimise laboratory and field sampling methods for routine monitoring of nematode infections in chickens by evaluating the sensitivity, accuracy, and precision of the Modified McMaster (MM) and Mini-FLOTAC (MF) methods using laying chicken excreta samples spiked with estimated true numbers of eggs (Experiment 1 = 5-1500 EPG (eggs/g); Experiment 2 = 5-500 EPG) without and with operator effects, respectively or using individual fresh excreta (n = 230) and fresh floor excreta (n = 42) from naturally infected free-range layer farms. The Coefficient of Variation (CV) was assessed within and between operators and the time spent on sample preparation and counting was also evaluated. MF was more sensitive than MM at ≤ 50 EPG level but not above this while MM had a significantly higher egg recovery rate than MF for ≥ 50 EPG levels (MM = 89.7 %, MF = 68.2 %; P < 0.0001). Operator factors did not have a significant effect (P = 0.358-0.998) on egg counts across methods and EPG levels. The CV between replicates of the MM and MF methods for ≥ 50 EPG was 43.4 and 36.5 %, respectively. The inter-observer CV of the MM and MF methods for ≥ 50 EPG levels was 63.8 and 44.3 % respectively. When the naturally infected free-range layers which were individual caged for excreta sampling, the proportion of samples positive for MM and MF were 91.7 and 96.5 %, respectively (P = 0.023). MM resulted in significantly (P = 0.029) higher excreta egg counts (604) than MF (460) with the difference between methods greatest at higher EPG levels. Fresh floor excreta (pooled or individual) and individual caged chicken excreta did not have significant effect on egg counts (P = 0.274). The total time taken for sample preparation and egg counting was significantly lower using the MM method (4.3-5.7 min) than the MF method (16.9-23.8 min) (P < 0.0001). In conclusion, MM was more accurate than MF, particularly at higher EPG levels, but slightly less precise and sensitive, particularly at low EPG levels, while taking less than 25 % of the laboratory time per sample. Our observations indicate that the MM method is more appropriate for rapid diagnosis of chicken nematodes in the field. Pooled fresh floor excreta samples would be sufficient to indicate infection level in free range farms.

Zoonotic Parasitological Findings in a Puppy: The Course and Therapeutical Efficacy

Considering the close contact of companion animals and humans, gastrointestinal parasitic zoonoses are very widespread and represent a high risk of transmission with the potential of severe consequences affecting the digestive tract of both humans and other animals. In this study we focused on enteric zoonoses caused by Toxocara canis nematode, Dipylidium caninum tapeworm and Giardia duodenalis protozoa. Our primary aim was to observe Toxocara canis egg excretion within the 27 consecutive days before and after orally treatment (2 Caniverm® tablets) on Day 13 in a naturally infected puppy. An average egg per gram (EPG) of T. canis detected by coprological quantitative McMaster method was 4558.33 and 666.66, before and after treatment, respectively. The percentage of faecal egg count reduction (%FECR) in in vivo Faecal Egg Count Reduction Test (FECRT) has confirmed an 85.37 % efficacy against T. canis. Secondly, the efficacy of Caniverm® against the tapeworm Dipylidium caninum was also determined. No D. caninum proglottides were detected on Day 14. The data showed 100 % effectiveness of the anthelmintic treatment. Metrobactin® 250 mg has been tested as experimental therapy against Giardia duodenalis on Day 3. On day 10, no cysts were observed in the faeces after per os ¼ tablet administration twice a day for 7 days.

A low-cost, automated parasite diagnostic system via a portable, robotic microscope and deep learning

Manual hand counting of parasites in fecal samples requires costly components and substantial expertise, limiting its use in resource-constrained settings and encouraging overuse of prophylactic medication. To address this issue, a cost-effective, automated parasite diagnostic system that does not require special sample preparation or a trained user was developed. It is composed of an inexpensive (~US$350), portable, robotic microscope that can scan over the size of an entire McMaster chamber (100 mm² ) and capture high-resolution (~1 μm lateral resolution) bright field images without need for user intervention. Fecal samples prepared using the McMaster flotation method were imaged, with the imaging region comprising the entire McMaster chamber. These images are then automatically segmented and analyzed using a trained convolution neural network (CNN) to robustly separate eggs from background debris. Simple postprocessing of the CNN output yields both egg species and egg counts. The system was validated by comparing accuracy with hand-counts by a trained operator, with excellent performance. As a further demonstration of utility, the system was used to conveniently quantify drug response over time in a single animal, showing residual disease due to Anthelmintic resistance after 2 weeks.

Prevalence and associated risk factors of Toxocara infection in dogs in northern and southern Egypt

Toxocariasis is a zoonotic disease with a worldwide distribution caused by the parasitic roundworms, Toxocara canis, commonly found in the intestine of dogs. Identification of frequent shedders for Toxocara canis eggs and the associated risk factors overwhelmingly remain an important cornerstone of conducting evidence-based deworming regimens to reduce the environmental contamination with the parasite eggs. The present study was undertaken to prevalence rate of shedding of Toxocara canis eggs in dogs in Egypt combined with the possible risk factors naturally associated with the infection A total number of 296 fecal samples of dogs were collected in the period from July 2016 to June 2017 and properly screened for the presence of possible infection with an. Importantly, The overall prevalence of Toxocara canis eggs was 53.04% whereas, seasonal dynamics, dog breeds, the irregular anthelmintic use, defecation sites, and unconfined management of dogs were among the risk factors with a significant association with Toxocara canis infection. Taken together, our present data reveal the high overall prevalence of Toxocara canis eggs shedding in in several Egyptian provinces and provide novel information that should pay our attention of the local authorities combined with the public engagement towards implementation of effective control strategies against this disease of zoonotic importance.

Diagnosis and drug resistance of human soil-transmitted helminth infections: A public health perspective

Soil-transmitted helminth (STH) infections represent a major public health problem globally, particularly among socio-economically disadvantaged populations. Detection of STH infections is often challenging, requiring a combination of diagnostic techniques to achieve acceptable sensitivity and specificity, particularly in low infection-intensity situations. The microscopy-based Kato-Katz remains the most widely used method but has low sensitivity in the detection of, for instance, Strongyloides spp. infections, among others. Antigen/antibody assays can be more sensitive but are parasite species-specific. Highly sensitive PCR methods have been developed to be multiplexed to allow multi-species detection. Novel diagnostic tests for all STH species are needed for effective monitoring, evaluation of chemotherapy programmes, and to assess the potential emergence of parasite resistance. This review discusses available diagnostic methods for the different stages of STH control programmes, which vary in sensitivity and spectrum of detection requirements, and tools to evaluate drug efficacy and resistance.

A comparison of two different anthelmintic treatment regimens against natural gastrointestinal nematode infections on two Lithuanian sheep farms

Background

According to targeted treatment (TT), the whole flock is dewormed based on knowledge of the risk, or parameters that quantify the mean level of infection, whereas according to targeted selective treatment (TST), only individual animals within the grazing group are treated, based on parasitological, production and/or morbidity parameters. The aim of this study was to compare two different treatment protocols on sheep farms in Lithuania. The study was conducted from 15 April to 31 October 2014 on three sheep farms. On the TT (the whole flock) and T(S)T (with FECs ≥ 300, respectively) farms all adult animals were treated orally with fenbendazole irrespective of EPG counts before the grazing season. The second treatment was applied with injectable ivermectin on both farms. However, on the TT farm all sheep were also treated on 2nd August regardless of their EPG counts, while on the T(S)T farm only those animals with an EPG ≥ 300 were treated on 1 July using a threshold of ≥ 300 EPG. No treatments were administered on the control farm (n = 1) during the study.

Results

Spring treatment of ewes significantly reduced nematode faecal egg counts (FEC) both on the TT and T(S)T farms, with the benefit of lowering pasture contamination with infective L₃ stage larvae at the start of grazing season, while it remained significantly higher on the control farm. The positive effect of the spring treatment of ewes was reflected by increased body weight gains (BWG) in lambs in the first half of the grazing season. Following the second treatment, the weight gains in lambs on the T(S)T farm were higher compared to lambs on the TT farm, while BWG in the control lambs started to decrease. The difference was also substantiated by the body condition scores (BCS) and dag scores (DS) of lambs, which were highest on the T(S)T farm compared with those on the control and TT farms.

Conclusions

The results of this study show that both treatment strategies were useful in reducing clinical effects (BCS and DS) of gastrointestinal nematode parasitism and increasing the performance in lambs. Furthermore, on the T(S)T farm some of animals were left in refugia, helping to slow down the development of anthelmintic resistance (AR) in future.

Gastrointestinal parasitic infection in diverse species of domestic birds of Manipur, India

Domesticated birds (515) consisting of 185 broiler (Gallusgallusdomesticus), 130 layers (Gallus Sp), 75 free range local chicken (Gallusdomesticus), 40 house pigeon (Columbalivia), 70 ducks (Anasplatyrhynchos) and 15 turkeys (Melleagrisgallopavo) reared in valley districts of Manipur were investigated for intestinal protozoan and helminthic infections. Fresh faecal samples of these birds were examined microscopically by direct wet smear with 2.5 % potassium dichromate (K₂Cr₂O₇). Of these 412 (80 %) were found to be infected with different species of gastrointestinal parasites. The highest (90.8 %) prevalence of these parasitic infections was found in broiler followed by layer (78.5 %), duck (75.7 %), house pigeon (75 %), Turkey (66.7 %) and free range local chicken (65.3 %), etc. A total of 10 species of intestinal parasites were encountered. Among these, the protozoans Eimeria and Isospora were the most common (68.3 %) followed by mixed infection of protozoan and Helminths.

Field study analysis of the influences of deworming regimens and housing conditions on parasites and sperm output in 21 European boar studs

The current study reports the parasitological results of a quality control audit in 21 European boar studs. Field investigations were performed over a 2-year period (2012-2013) during the winter and spring. From each stud, an average of 30 (range, 25-33) individual faecal samples and ejaculates from 615 randomly selected Pietrain boars were analysed. Statistical analysis revealed a significant effect (P < 0.0001) of deworming regimen (DR) × age class of boar (A) and housing condition (H) × A on the presence of parasites. A second model indicated a significant effect (P = 0.0262) of DR × H × A on the presence of parasites. Sperm output was significantly affected (P < 0.0001) by the DR. Based on this study, recommendations for deworming AI boars are proposed.

Methods of preservation and flotation for the detection of nematode eggs and coccidian oocysts in faeces of the forest musk deer

Parasitic infections influence the health of captive forest musk deer (Moschus berezovskii) and affect population increases. Nevertheless, there are few quantitative studies regarding forest musk deer parasites, and there is no common preservation method or flotation solution used for detection of faecal parasites because of the biology of the worms and the host physiological state. The objective of this study was to evaluate preservation and flotation methods for the detection of nematode eggs and coccidian oocysts in faeces of the forest musk deer. The McMaster technique was used to count nematode eggs and coccidian oocysts in 33 samples of faeces. For the nematode eggs, the differences among flotation solutions were significant (P< 0.01), with sodium nitrate being the best flotation solution, and the combination of freezing and sodium nitrate resulted in the greatest number of eggs per gram (EPG = 209.4 ± 67.8). For the coccidian oocysts, the interaction between preservation method and flotation solution was significant (P< 0.01), and the combination of formalin and sodium chloride yielded the greatest number of oocysts per gram (OPG = 1010.7 ± 162.3). The forest musk deer had a high prevalence of parasitic infections, with the parasite load of coccidia (96.4%) significantly greater than that of nematodes (71.9%, P< 0.01). These results confirm that captive forest musk deer suffer from serious parasitic invasions and demonstrate that the novel method described here could be utilized for parasitological diagnosis, detection and prevention in species of Moschidae and Cervidae.

Uses and limitations of faecal egg count for assessing worm burden in wild boars

The most widely used technique to assess helminth infection in both domestic and wild mammals is the faecal egg count (FEC). Most efforts to test the reliability of FEC as a proxy for parasite load are in small ruminant studies and limited work has evaluated the use of FEC in pigs. The aim of this study was to explore whether FEC is a reliable indicator of helminth load, and to evaluate the effects of sample storage on FEC accuracy in 59 wild boars. Though FEC was useful for assessing most helminth infections (e.g., Metastrongylus spp., Ascaris suum, Trichuris suis), stomach nematodes were often missed. The accuracy of FEC decreased over time, and thus it is recommended that samples be processed within 5 days of collection.

A survey of gastro-intestinal parasitic infection in domestic and wild birds in Chittagong and Greater Sylhet, Bangladesh

A survey of gastrointestinal parasitic infection as determined by faecal examination was conducted among domestic and wild birds in Bangladesh. Birds were sampled from households, wet markets and wetlands in Chittagong and Greater Sylhet districts during April 2012 to February 2013. Mist nets were used to catch resident wild and migratory birds. The overall prevalence of parasitic infection ranged among locations from 25 to 55% in indigenous domestic ducks (live bird samples=304), 20% in resident wild birds (environmental faecal samples=40) and 40% in migratory birds (live bird samples=35). The prevalence of parasitic infection was significantly higher in indigenous domestic ducks collected during summer (39%) than winter (22%) (p=0.04). In domestic indigenous ducks and Muscovy ducks, both single and multiple types of parasitic infections were found. However, other domestic birds and wild birds often had a single type of parasitic infection. Ascaridia spp. with an average egg load of 50-900, was commonly detected in faecal samples of domestic and wild birds in this study. Other identified parasites were Capillaria spp. and Heterakis spp. both in domestic and wild birds. Improvement of biosecurity measures for household duck farms through educating and motivating household farmers could help mitigate the effects of parasitic infection on production.

American Association of Veterinary Parasitologists' review of veterinary fecal flotation methods and factors influencing their accuracy and use--is there really one best technique?

The principle of fecal flotation is based on the ability of a solution to allow less dense material (including parasite elements) to rise to the top. However, there are numerous factors that will influence the accuracy and use of such a theoretically simple technique. Whether or not centrifugation is used appears to have an impact on the ability to detect some parasites, but not others. Using a flotation solution with a relatively high specific gravity favors the simultaneous flotation of the diagnostic stages of many different parasites while, at the same time, making recognition of some more difficult because of distortion as well as the amount of debris in the preparation. Dilution methods tend to be less accurate because they require extrapolation; however, they are quicker to perform, in part, because of the cleaner preparation. Timing is a critical factor in the success of all flotation methods, as is technical ability of the personnel involved. Thus, simplicity, low costs and time savings have generally favored gravitational flotation techniques (including the McMaster technique and its modifications). How accurate the method needs to be is dependent upon the purpose of its use and choice of method requires an understanding of analytical sensitivity and expected levels of egg excretion. In some instances where the difference between, for example, 0 and 50 eggs per gram is insignificant with regards to management decisions, less accurate methods will suffice. In others, where the presence of a parasite means treatment of the animal regardless of the numbers of eggs present, methods with higher analytical sensitivities will be required, particularly for those parasites that pass few eggs. For other uses, such as the Fecal Egg Count Reduction Test, accuracy may become critical. Therefore, even though recommendations for standardized fecal flotation procedures have been promoted in the past, it is clear that the factors are too numerous to allow for the recommendation of one, or even a few, procedures for all purposes.

A simple method to count total faecal Capillaria worm eggs in racing pigeons (Columba livia)

Capillaria columbae and C. longicollis are fine threadworms found in racing pigeons' small intestines that produce a characteristic lemon shaped bipolar egg. Clinically, capillariasis in racing pigeons can present as severe illness and it has been suggested that worms may affect race performance. A major aim of this study was to validate a cheap, simple to perform flotation technique for counting Capillaria worm eggs in racing pigeon droppings. Trials using reference samples of pigeon droppings laced with 348, 275 and 129 Capillaria eggs per gram, found a typical flotation method based on the modified Wisconsin technique to be inaccurate at counting worm eggs. The main sources of error were due to the loss of eggs in the faecal discard and insufficient flotation time. A new technique, using 0.15 g sample size and 8h flotation time resulted in significantly improved test accuracy. On average the new technique recovered 93% of eggs from reference samples with 129-348 epg concentration, recovering 197 times more eggs than the modified Wisconsin technique. Typical percentage error, as a measure of absolute reliablility, was 10% for the new technique and 50% for the modified Wisconsin technique. The regression line on a test-retest series of samples over a range of egg counts from 0 to 573 epg had a gradient of 0.96 (y=0.96x+6.28; r(2)=0.8408) for the new technique and 0.54 (y=0.54x+0.06; r(2)=0.4249) for the modified Wisconsin technique. The Pearson product moment correlations of the new technique and the modified Wisconsin technique were 0.92 and 0.65 respectively. As measures of relative reliability both the gradient of the regression line and the Pearson product moment correlation further suggested better repeatability of the new technique. It was concluded that the new technique would be an appropriate quantitative method of assessing worm egg burdens in racing pigeons.

Analysis of the accuracy and precision of the McMaster method in detection of the eggs of Toxocara and Trichuris species (Nematoda) in dog faeces

The aim of this study was to determine the accuracy and precision of McMaster method with Raynaud's modification in the detection of the eggs of the nematodes Toxocara canis (Werner, 1782) and Trichuris ovis (Abildgaard, 1795) in faeces of dogs. Four variants of McMaster method were used for counting: in one grid, two grids, the whole McMaster chamber and flotation in the tube. One hundred sixty samples were prepared from dog faeces (20 repetitions for each egg quantity) containing 15, 25, 50, 100, 150, 200, 250 and 300 eggs of T. canis and T. ovis in 1 g of faeces. To compare the influence of kind of faeces on the results, samples of dog faeces were enriched at the same levels with the eggs of another nematode, Ascaris suum Goeze, 1782. In addition, 160 samples of pig faeces were prepared and enriched only with A. suum eggs in the same way. The highest limit of detection (the lowest level of eggs that were detected in at least 50% of repetitions) in all McMaster chamber variants were obtained for T. canis eggs (25-250 eggs/g faeces). In the variant with flotation in the tube, the highest limit of detection was obtained for T. ovis eggs (100 eggs/g). The best results of the limit of detection, sensitivity and the lowest coefficients of variation were obtained with the use of the whole McMaster chamber variant. There was no significant impact of properties of faeces on the obtained results. Multiplication factors for the whole chamber were calculated on the basis of the transformed equation of the regression line, illustrating the relationship between the number of detected eggs and that of the eggs added to the'sample. Multiplication factors calculated for T. canis and T. ovis eggs were higher than those expected using McMaster method with Raynaud modification.

The bias, accuracy and precision of faecal egg count reduction test results in cattle using McMaster, Cornell-Wisconsin and FLOTAC egg counting methods

The faecal egg count reduction test (FECRT) is the recommended method to monitor anthelmintic drug efficacy in cattle. There is a large variation in faecal egg count (FEC) methods applied to determine FECRT. However, it remains unclear whether FEC methods with an equal analytic sensitivity, but with different methodologies, result in equal FECRT results. We therefore, compared the bias, accuracy and precision of FECRT results for Cornell-Wisconsin (analytic sensitivity = 1 egg per gram faeces (EPG)), FLOTAC (analytic sensitivity = 1 EPG) and McMaster method (analytic sensitivity = 10 EPG) across four levels of egg excretion (1-49 EPG; 50-149 EPG; 150-299 EPG; 300-600 EPG). Finally, we assessed the sensitivity of the FEC methods to detect a truly reduced efficacy. To this end, two different criteria were used to define reduced efficacy based on FECR, including those described in the WAAVP guidelines (FECRT <95% and lower limit of 95%CI <90%) (Coles et al., 1992) and those proposed by El-Abdellati et al. (2010) (upper limit of 95%CI <95%). There was no significant difference in bias and accuracy of FECRT results across the three methods. FLOTAC provided the most precise FECRT results. Cornell-Wisconsin and McMaster gave similar imprecise results. FECRT were significantly underestimated when baseline FEC were low and drugs were more efficacious. For all FEC methods, precision and accuracy of the FECRT improved as egg excretion increased, this effect was greatest for McMaster and least for Cornell-Wisconsin. The sensitivity of the three methods to detect a truly reduced efficacy was high (>90%). Yet, the sensitivity of McMaster and Cornell-Wisconsin may drop when drugs only show sub-optimal efficacy. Overall, the study indicates that the precision of FECRT is affected by the methodology of FEC, and that the level of egg excretion should be considered in the final interpretation of the FECRT. However, more comprehensive studies are required to provide more insights into the complex interplay of factors inherent to study design (sample size and FEC method) and host-parasite interactions (level of egg excretion and aggregation across the host population).

Novel insights in the fecal egg count reduction test for monitoring drug efficacy against soil-transmitted helminths in large-scale treatment programs

BACKGROUND

The fecal egg count reduction test (FECRT) is recommended to monitor drug efficacy against soil-transmitted helminths (STHs) in public health. However, the impact of factors inherent to study design (sample size and detection limit of the fecal egg count (FEC) method) and host-parasite interactions (mean baseline FEC and aggregation of FEC across host population) on the reliability of FECRT is poorly understood.

METHODOLOGY/PRINCIPAL FINDINGS

A simulation study was performed in which FECRT was assessed under varying conditions of the aforementioned factors. Classification trees were built to explore critical values for these factors required to obtain conclusive FECRT results. The outcome of this analysis was subsequently validated on five efficacy trials across Africa, Asia, and Latin America. Unsatisfactory (<85.0%) sensitivity and specificity results to detect reduced efficacy were found if sample sizes were small (<10) or if sample sizes were moderate (10-49) combined with highly aggregated FEC (k<0.25). FECRT remained inconclusive under any evaluated condition for drug efficacies ranging from 87.5% to 92.5% for a reduced-efficacy-threshold of 90% and from 92.5% to 97.5% for a threshold of 95%. The most discriminatory study design required 200 subjects independent of STH status (including subjects who are not excreting eggs). For this sample size, the detection limit of the FEC method and the level of aggregation of the FEC did not affect the interpretation of the FECRT. Only for a threshold of 90%, mean baseline FEC <150 eggs per gram of stool led to a reduced discriminatory power.

CONCLUSIONS/SIGNIFICANCE

This study confirms that the interpretation of FECRT is affected by a complex interplay of factors inherent to both study design and host-parasite interactions. The results also highlight that revision of the current World Health Organization guidelines to monitor drug efficacy is indicated. We, therefore, propose novel guidelines to support future monitoring programs.

A comparison of the sensitivity and fecal egg counts of the McMaster egg counting and Kato-Katz thick smear methods for soil-transmitted helminths

Background

The Kato-Katz thick smear (Kato-Katz) is the diagnostic method recommended for monitoring large-scale treatment programs implemented for the control of soil-transmitted helminths (STH) in public health, yet it is difficult to standardize. A promising alternative is the McMaster egg counting method (McMaster), commonly used in veterinary parasitology, but rarely so for the detection of STH in human stool.

Methodology/Principal Findings

The Kato-Katz and McMaster methods were compared for the detection of STH in 1,543 subjects resident in five countries across Africa, Asia and South America. The consistency of the performance of both methods in different trials, the validity of the fixed multiplication factor employed in the Kato-Katz method and the accuracy of these methods for estimating ‘true’ drug efficacies were assessed. The Kato-Katz method detected significantly more Ascaris lumbricoides infections (88.1% vs. 75.6%, p<0.001), whereas the difference in sensitivity between the two methods was non-significant for hookworm (78.3% vs. 72.4%) and Trichuris trichiura (82.6% vs. 80.3%). The sensitivity of the methods varied significantly across trials and magnitude of fecal egg counts (FEC). Quantitative comparison revealed a significant correlation (Rs >0.32) in FEC between both methods, and indicated no significant difference in FEC, except for A. lumbricoides, where the Kato-Katz resulted in significantly higher FEC (14,197 eggs per gram of stool (EPG) vs. 5,982 EPG). For the Kato-Katz, the fixed multiplication factor resulted in significantly higher FEC than the multiplication factor adjusted for mass of feces examined for A. lumbricoides (16,538 EPG vs. 15,396 EPG) and T. trichiura (1,490 EPG vs. 1,363 EPG), but not for hookworm. The McMaster provided more accurate efficacy results (absolute difference to ‘true’ drug efficacy: 1.7% vs. 4.5%).

Conclusions/Significance

The McMaster is an alternative method for monitoring large-scale treatment programs. It is a robust (accurate multiplication factor) and accurate (reliable efficacy results) method, which can be easily standardized.

Currently, in public health, the reduction in the number of eggs excreted in stools after drug administration is used to monitor the efficacy of drugs against parasitic worms. Yet, studies comparing diagnostic methods for the enumeration of eggs in stool are few. We compared the Kato-Katz thick smear (Kato-Katz) and McMaster egg counting (McMaster) methods, which are commonly used diagnostic methods in public and animal health, respectively, for the diagnosis and enumeration of eggs of roundworms, whipworms and hookworms in 1,536 stool samples from children in five trials across Africa, Asia and South America. The Kato-Katz method was the most sensitive for the detection of roundworms, but there was no significant difference in sensitivity between the methods for hookworms and whipworms. The sensitivity of the methods differed across the trials and magnitude of egg counts. The Kato-Katz method resulted in significantly higher egg counts, but these were subject to lack of accuracy caused by intrinsic properties of this method. McMaster provided more reliable estimates of drug efficacies. We conclude that the McMaster is an alternative method for monitoring large-scale treatment programs. It allows accurate monitoring of drug efficacy and can be easily performed under field conditions.

Field validity and feasibility of four techniques for the detection of Trichuris in simians: a model for monitoring drug efficacy in public health?

Background

Soil-transmitted helminths, such as Trichuris trichiura, are of major concern in public health. Current efforts to control these helminth infections involve periodic mass treatment in endemic areas. Since these large-scale interventions are likely to intensify, monitoring the drug efficacy will become indispensible. However, studies comparing detection techniques based on sensitivity, fecal egg counts (FEC), feasibility for mass diagnosis and drug efficacy estimates are scarce.

Methodology/Principal Findings

In the present study, the ether-based concentration, the Parasep Solvent Free (SF), the McMaster and the FLOTAC techniques were compared based on both validity and feasibility for the detection of Trichuris eggs in 100 fecal samples of nonhuman primates. In addition, the drug efficacy estimates of quantitative techniques was examined using a statistical simulation. Trichuris eggs were found in 47% of the samples. FLOTAC was the most sensitive technique (100%), followed by the Parasep SF (83.0% [95% confidence interval (CI): 82.4–83.6%]) and the ether-based concentration technique (76.6% [95% CI: 75.8–77.3%]). McMaster was the least sensitive (61.7% [95% CI: 60.7–62.6%]) and failed to detect low FEC. The quantitative comparison revealed a positive correlation between the four techniques (Rs = 0.85–0.93; p<0.0001). However, the ether-based concentration technique and the Parasep SF detected significantly fewer eggs than both the McMaster and the FLOTAC (p<0.0083). Overall, the McMaster was the most feasible technique (3.9 min/sample for preparing, reading and cleaning of the apparatus), followed by the ether-based concentration technique (7.7 min/sample) and the FLOTAC (9.8 min/sample). Parasep SF was the least feasible (17.7 min/sample). The simulation revealed that the sensitivity is less important for monitoring drug efficacy and that both FLOTAC and McMaster were reliable estimators.

Conclusions/Significance

The results of this study demonstrated that McMaster is a promising technique when making use of FEC to monitor drug efficacy in Trichuris.

Worldwide, millions of people are infected with soil-transmitted helminths, particularly in developing countries. Efforts to control these infections involve periodic mass drug treatment in endemic areas. Since these large-scale interventions are likely to intensify, monitoring of drug efficacy has become a key issue in order to detect the emergence of resistance. At present, the drop in infection intensity is under examination for monitoring the drug efficacy. However, studies comparing detection techniques based on infection intensities are scarce. Moreover, little attention has been addressed to their feasibility and their ability to estimate drug efficacies. We have compared different techniques for the detection of whipworm (Trichuris) in simian stool samples based on prevalence, infection intensities, feasibility and ability to estimate the ‘true’ drug efficacy. We have found that techniques often fail to detect low infection intensities and that not all techniques are appropriate for estimating infection intensities. The time needed to obtain a test result varied from 3.9 to 17.7 min/sample. Finally, accurate estimates of drug efficacy were only obtained in high pre-drug administration infection intensities. To conclude, along with accurate estimates of infection intensities, feasibility is a considerable criterion for the detection techniques used in drug efficacy monitoring programs.