Which McMaster egg counting technique is the most reliable?

Molecular detection of Cooperia oncophora and Ostertagia ostertagi in cattle: Comparison of sample processing and detection on ddPCR and qPCR platforms

Faecal samples were obtained from 77 first season grazers from 20 Norwegian dairy herds in autumn 2020 for analysis of Cooperia oncophora and Ostertagia ostertagi infection. Strongylid eggs per gram of faeces (EPG) were determined for each sample and the samples underwent larval culture. DNA was extracted from the faeces at different stages of the culture preparation: from faecal slurry (FS), direct extraction before culture (DBC), and direct extraction after culture (DAC). Extracted DNA was subject to molecular assay for both C. oncophora and O. ostertagi using both a published ddPCR assay and a modified qPCR duplex assay targeting the ITS-2 gene. For C. oncophora, DBC samples contained significantly less ITS-2 copies than DAC and FS samples (p ≤ 0.0001 for both) for qPCR, but not between DAC and FS samples (p = 0.339). Droplet digital PCR with DBC samples yielded significantly fewer ITS-2 copies than DAC and FS samples (p ≤ 0.0001). For O. ostertagi, the ITS-2 copies in DBC samples differed significantly from levels in DAC and FS samples on the qPCR platform (p=0.002 and 0.044, respectively) as was the case with ddPCR (p ≤ 0.0001 and 0.0137). Overall, across the various processing techniques, C. oncophora results obtained on both ddPCR and qPCR platforms correlated with EPG better than was found for equivalent results for O. ostertagi and results are strongly indicative of poor correlation when EPG counts are low. Results from this study suggest that DAC faecal processing was of limited practical use.

POPULATION DYNAMICS OF ENTERIC PARASITES IN THE ENDANGERED VANCOUVER ISLAND MARMOT (MARMOTA VANCOUVERENSIS)

Enteric parasites can have wide-ranging effects throughout an ecosystem, often driving coevolutionary and ecological processes. Parasites have long been overlooked in conservation efforts because of the negative impact inflicted on their hosts; however, parasites make up a significant component of Earth's biodiversity and host conservation efforts need to be parasite inclusive. The Vancouver Island marmot (VIM), Marmota vancouverensis, is an endangered alpine rodent endemic to Vancouver Island, British Columbia, Canada. Captive-bred VIMs are released to augment the wild population, but their susceptibility to parasites is unknown. The objectives of this study were to describe the diversity, prevalence, severity, and temporal variation of VIM enteric parasites. Noninvasive fecal samples were collected from wild and captive marmots and analyzed using a modified McMaster fecal egg floatation technique to indicate parasite prevalence and relative mean abundance. We identified oocysts and ova from 3 parasite taxa including a protozoan coccidium not previously described in the VIM (prevalence 68%), an ascarid nematode Baylisascaris laevis (prevalence 82%), and an anoplocephalid cestode Diandrya vancouverensis (prevalence 8%). Depending on the species, comparisons revealed variation in parasite infection by sex, by colony, and between wild and captive VIMs, but not among age classes or by female reproductive status. Finally, captive VIMs displayed significant monthly variation in parasite prevalence and mean egg abundance, suggesting a seasonal influence on parasite egg shedding. This information is critically important for future research investigating the influences of these trends on the health, ecology, and conservation of VIMs and their parasites.

An environmental evaluation of urine-diverting dry toilets in Hiloweyn Camp, Dollo Ado, Ethiopia

Safe and hygienic management of human waste is essential in humanitarian settings. Urine-diverting dry toilets (UDDTs) can enable this management in some humanitarian emergency settings. A seeded, longitudinal environmental study was conducted in Hiloweyn refugee camp, Dollo Ado, Ethiopia, to measure Escherichia coli and Ascaris suum ova inactivation within closed UDDT vaults and to document environmental conditions (temperature, moisture content, and pH) that could influence inactivation. Hiloweyn camp represented an optimal location for a desiccation-based sanitation technology such as the UDDT. E. coli and Ascaris ova inactivation was observed in UDDTs under warm, dry, alkaline conditions at 6, 9, and 12 months of storage; UDDTs with samples containing <1000 E. coli/g total solids increased from 30 % to 95 % over 12 months, and a >2.8-log10 reduction in Ascaris ova viability was observed after 6 months. Additional laboratory-based studies were conducted to provide insights into the field study findings and study the impact of hydrated lime on E. coli and Ascaris ova inactivation. Results suggest that adding hydrated lime to elevate pH > 12 may increase inactivation and decrease storage time. Overall, UDDTs could contribute to the safe and hygienic management of human waste in comparable warm and dry humanitarian settings.

Identification and characterization of the receptors of a microneme adhesive repeat domain of Eimeria maxima microneme protein 3 in chicken intestine epithelial cells

Eimeria maxima microneme protein 3 (EmMIC3) is pivotal in the initial recognition and attachment of E. maxima sporozoites to host cells. EmMIC3 comprises 5 tandem Type I microneme adhesive repeat (MAR) domains, among which MAR2 of EmMIC3 (EmMAR2) has been identified as the primary determinant of EmMIC3-mediated tissue tropism. Nonetheless, the mechanisms through which EmMAR2 guides the parasite to its invasion site through interactions with host receptors remained largely uncharted. In this study, we employed yeast two-hybrid (YTH) screening assays and shotgun LC-MS/MS analysis to identify EmMAR2 receptors in chicken intestine epithelial cells. ATPase H+ transporting V1 subunit G1 (ATP6V1G1), receptor accessory protein 5 (REEP5), transmembrane p24 trafficking protein (TMED2), and delta 4-desaturase sphingolipid 1 (DEGS1) were characterized as the 4 receptors of EmMAR2 by both assays. By blocking the interaction of EmMAR2 with each receptor using specific antibodies, we observed varying levels of inhibition on the invasion of E. maxima sporozoites, and the combined usage of all 4 antibodies resulted in the most pronounced inhibitory effect. Additionally, the spatio-temporal expression profiles of ATP6V1G1, REEP5, TMED2, and DEGS1 were assessed. The tissue-specific expression patterns of EmMAR2 receptors throughout E. maxima infection suggested that ATP6V1G1 and DEGS1 might play a role in early-stage invasion, whereas TMED2 could be involved in middle and late-stage invasion and REEP5 and DEGS1 may participate primarily in late-stage invasion. Consequently, E. maxima may employ a multitude of ligand-receptor interactions to drive invasion during different stages of infection. This study marks the first report of EmMAR2 receptors at the interface between E. maxima and the host, providing insights into the invasion mechanisms of E. maxima and the pathogenesis of coccidiosis.

Periodicity of Ascaridia galli egg excretion in experimentally infected chicken in the Philippines

The periodicity of parasite egg excretion refers to variations in the number of eggs produced across time, with significant implications in optimizing diagnostic procedures and conducting the Fecal Egg Count Reduction Test (FECRT). Here, we explore whether Ascaridia galli egg excretion varies across time under Philippine conditions, thus informing the best time to collect fecal samples during flock health examination. A time-course analysis was performed in chickens (N = 12) experimentally infected with A. galli, isolated from a naturally infected Philippine native chicken. We examined the fecal egg per gram (EPG) count at 3-h intervals for 3 days, starting from 5:00-6:00 h AM to the following day at 1:00-2:00 h AM. Our results showed a consistent daily egg excretion pattern with a peak EPG count in the morning that abruptly declined in the afternoon and lowest in the evening. The EPG counts correlated with the amount of excreta produced, suggesting that A. galli fecundity corresponds to the timing of host defecation. Our results imply that the best time to collect fecal samples for A. galli diagnosis and FECRT in Philippine conditions should be from sunrise until late morning when parasite EPG count and host excreta production are at their highest.

The microneme adhesive repeat domain of MIC3 protein determined the site specificity of Eimeria acervulina, Eimeria maxima, and Eimeria mitis

Understanding the determinants of host and tissue tropisms among parasites of veterinary and medical importance has long posed a substantial challenge. Among the seven species of Eimeria known to parasitize the chicken intestine, a wide variation in tissue tropisms has been observed. Prior research suggested that microneme protein (MIC) composed of microneme adhesive repeat (MAR) domain responsible for initial host cell recognition and attachment likely dictated the tissue tropism of Eimeria parasites. This study aimed to explore the roles of MICs and their associated MARs in conferring site-specific development of E. acervuline, E. maxima, and E. mitis within the host. Immunofluorescence assays revealed that MIC3 of E. acervuline (EaMIC3), MIC3 of E. maxima (EmMIC3), MIC3 of E. mitis (EmiMIC3), MAR3 of EaMIC3 (EaMIC3-MAR3), MAR2 of EmMIC3 (EmMIC3-MAR2), and MAR4 of EmiMIC3 (EmiMIC3-MAR4), exhibited binding capabilities to the specific intestinal tract where these parasites infect. In contrast, the invasion of sporozoites into host intestinal cells could be significantly inhibited by antibodies targeting EaMIC3, EmMIC3, EmiMIC3, EaMIC3-MAR3, EmMIC3-MAR2, and EmiMIC3-MAR4. Substitution experiments involving MAR domains highlighted the crucial roles of EaMIC3-MAR3, EmMIC3-MAR2, and EmiMIC3-MAR4 in governing interactions with host ligands. Furthermore, animal experiments substantiated the significant contribution of EmiMIC3, EmiMIC3-MAR4, and their polyclonal antibodies in conferring protective immunity to Eimeria-affiliated birds. In summary, EaMIC3, EmMIC3, and EmiMIC3 are the underlying factors behind the diverse tissue tropisms exhibited by E. acervuline, E. maxima, and E. mitis, and EaMIC3-MAR3, EmMIC3-MAR2, and EmiMIC3-MAR4 are the major determinants of MIC-mediated tissue tropism of each parasite. The results illuminated the molecular basis of the modes of action of Eimeria MICs, thereby facilitating an understanding and rationalization of the marked differences in tissue tropisms among E. acervuline, E. maxima, and E. mitis.

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.

A comparison of Mini-FLOTAC and McMaster techniques, overdispersion and prevalence of parasites in naturally infected North American bison (Bison bison) in the USA

Several quantitative diagnostic techniques are available to estimate gastrointestinal parasite counts in the feces of ruminants. Comparing egg and oocyst magnitudes in naturally infected samples has been a recommended approach to rank fecal techniques. In this study, we compared the Mini-FLOTAC (sensitivity of 5 eggs per gram (EPG)/oocysts per gram (OPG)) and different averaged replicates of the modified McMaster techniques (sensitivity of 33.33 EPG/OPG) in 387 fecal samples from 10 herds of naturally infected North American bison in the Central Great Plains region of the USA. Both techniques were performed with fecal slurries homogenized in a fill-FLOTAC device. In the study population, prevalence of strongyle eggs, Eimeria spp. oocysts, Moniezia spp. eggs and Trichuris spp. eggs was 81.4%, 73.9%, 7.5%, and 3.1%, respectively. Counts of strongyle eggs and Eimeria spp. oocysts obtained from 1 to 3 averaged technical replicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC. Correlation between the two techniques increased with an increase in the number of averaged technical replicates of the modified McMaster technique used to calculate EGP/OPG. The correlation for Moniezia spp. EPG when averaged triplicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC count was high; however, the correlation for Trichuris spp. eggs was low. Additionally, we used averaged counts from both techniques to show the overdispersion of parasites in bison herds.

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Mini-FLOTAC is an acceptable alternative to the McMaster for bison parasites.

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Increasing technical replicates of McMaster increases correlation with mini-FLOTAC.

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Gastrointestinal parasites are overdispersed in bison.

Comparison of Different Copromicroscopic Techniques in the Diagnosis of Intestinal and Respiratory Parasites of Naturally Infected Dogs and Cats

Simple Summary

Appropriate fecal examinations are very important for diagnosing parasitic diseases in dogs and cats. In this study, four different conventional copromicroscopic techniques (flotation, McMaster, Mini-FLOTAC, and Baermann) were evaluated for their performance in detecting intestinal and extra-intestinal parasitic elements in canine and feline feces. Stool samples from 100 dogs and 105 cats, respectively, were tested with the above techniques. Flotation and Mini-FLOTAC gave the best results in detecting intestinal and respiratory parasitoses by Toxocara spp., Toxascaris leonina, Ancylostomatidae, Cystoisospora spp., Trichuris vulpis and Capillaria spp., whereas the Baermann test was the best method for the detection of infections caused by metastrongyloids. These data provide useful information for veterinary clinicians on the most appropriate techniques to use during diagnostic paths in clinical settings.

Abstract

Several copromicroscopic techniques, including tools belonging to the FLOTAC group, are available for the qualitative and/or quantitative diagnosis of canine and feline parasitoses. The present study was carried out to compare the diagnostic performance of different copromicroscopic methods for detecting common intestinal and extra-intestinal parasites of dogs and cats. Fecal samples of 100 dogs and 105 cats were randomly selected from different regions of Italy. All samples were subjected to conventional flotation, McMaster, Mini-FLOTAC, and Baermann. Fifty-six dogs and twenty-five cats were found positive to at least one technique, and, among them, flotation (55% and 20.9% of the dogs and cats, respectively) and Mini-FLOTAC (52% and 20.9% of the dogs and cats, respectively) detected the highest number of positive samples. Larvae of the feline metastrongyloids Aelurostrongylus abstrusus and Troglostrongylus brevior were identified only using the Baermann test in two (1.9%) and one (0.9%) cat respectively. No larvae were found with the Baermann examination of dog feces or any of the other methods. The present results show that the Mini-FLOTAC represents a possible alternative to conventional flotation in clinical settings for the detection of intestinal and respiratory parasites e.g., Toxocara spp., Toxascaris leonina, Ancylostomatidae, Cystoisospora spp., Trichuris vulpis and Capillaria spp., although Baermann’s test remains the most recommended technique for the diagnosis of infections caused by metastrongyloid lungworms.

Comparison of FECPAKG2, a modified Mini-FLOTAC technique and combined sedimentation and flotation for the coproscopic examination of helminth eggs in horses

Background

Due to high prevalence of anthelmintic resistance in equine helminths, selective treatment is increasingly promoted and in some countries a positive infection diagnosis is mandatory before treatment. Selective treatment is typically recommended when the number of worm eggs per gram faeces (epg) exceeds a particular threshold. In the present study we compared the semi-quantitative sedimentation/flotation method with the quantitative methods Mini-FLOTAC and FECPAK^G2 in terms of precision, sensitivity, inter-rater reliability and correlation of worm egg counts to improve the choice of optimal diagnostic tools.

Methods

Using sedimentation/flotation (counting raw egg numbers up to 200), we investigated 1067 horse faecal samples using a modified Mini-FLOTAC approach (multiplication factor of 5 to calculate epgs from raw egg counts) and FECPAK^G2 (multiplication factor of 45).

Results

Five independent analyses of the same faecal sample with all three methods revealed that variance was highest for the sedimentation/flotation method while there were no significant differences between methods regarding the coefficient of variance. Sedimentation/flotation detected the highest number of samples positive for strongyle and Parascaris spp. eggs, followed by Mini-FLOTAC and FECPAK^G2. Regarding Anoplocephalidae, no significant difference in frequency of positive samples was observed between Mini-FLOTAC and sedimentation/flotation. Cohen’s κ values comparing individual methods with the combined result of all three methods revealed almost perfect agreement (κ ≥ 0.94) for sedimentation/flotation and strong agreement for Mini-FLOTAC (κ ≥ 0.83) for strongyles and Parascaris spp. For FECPAK^G2, moderate and weak agreements were found for the detection of strongyle (κ = 0.62) and Parascaris (κ = 0.51) eggs, respectively. Despite higher sensitivity, the Mini-FLOTAC mean epg was significantly lower than that with FECPAK^G2 due to samples with > 200 raw egg counts by sedimentation/flotation, while in samples with lower egg shedding epgs were higher with Mini-FLOTAC than with FECPAK^G2.

Conclusions

For the simple detection of parasite eggs, for example, to treat foals infected with Parascaris spp., sedimentation/flotation is sufficient and more sensitive than the other two quantitative investigared in this study. Mini-FLOTAC is predicted to deliver more precise results in faecal egg count reduction tests due to higher raw egg counts. Finally, to identify animals with a strongyle epg above a certain threshold for treatment, FECPAK^G2 delivered results comparable to Mini-FLOTAC.

Grpahical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05266-y.

Evaluation of in vitro methods of anthelmintic efficacy testing against Ascaridia galli

To investigate methods for in vitro assessment of anthelmintic efficacy against the chicken nematode Ascaridia galli this study firstly evaluated sample preparation methods including recovery of eggs from excreta using different flotation fluids and induced larval hatching by the deshelling-centrifugation method and the glass-bead method with or without bile. It then evaluated two in vitro assays, the in-ovo larval development assay (LDA) and larval migration inhibition assay (LMIA), for anthelmintic efficacy testing against A. galli using fresh eggs and artificially hatched larvae, respectively. Four anthelmintics, thiabendazole (TBZ), fenbendazole (FBZ), levamisole (LEV) and piperazine (PIP) were employed using an A. galli isolate of known susceptibility. The results suggested that the LDA and LMIA could successfully be used to generate concentration response curves for the tested drugs. The LDA provided EC50 values for inhibition of egg embryonation of 0.084 and 0.071 μg/ml for TBZ and FBZ, respectively. In the LMIA, the values of effective concentration (EC50) of TBZ, FBZ, LEV and PIP were 105.9, 6.32, 349.9 and 6.78 × 107 nM, respectively. For such in vitro studies, a saturated sugar solution showed high egg recovery efficiency (67.8%) and yielded eggs of the highest morphological quality (98.1%) and subsequent developmental ability (93.3%). The larval hatching assays evaluated did not differ in hatching efficiency but the deshelling-centrifugation method yielded larvae that had slightly better survival rates. For final standardization of these tests and establishment of EC50 reference values, tests using isolates of A. galli of defined resistance status need to be performed.

Membrane Technology for Rapid Point-of-Care Diagnostics for Parasitic Neglected Tropical Diseases

Parasitic neglected tropical diseases (NTDs) affect over one billion people worldwide, with individuals from communities in low-socioeconomic areas being most at risk and suffering the most. Disease management programs are hindered by the lack of infrastructure and resources for clinical sample collection, storage, and transport and a dearth of sensitive diagnostic methods that are inexpensive as well as accurate. Many diagnostic tests and tools have been developed for the parasitic NTDs, but the collection and storage of clinical samples for molecular and immunological diagnosis can be expensive due to storage, transport, and reagent costs, making these procedures untenable in most areas of endemicity. The application of membrane technology, which involves the use of specific membranes for either sample collection and storage or diagnostic procedures, can streamline this process, allowing for long-term sample storage at room temperature. Membrane technology can be used in serology-based diagnostic assays and for nucleic acid purification prior to molecular analysis. This facilitates the development of relatively simple and rapid procedures, although some of these methods, mainly due to costs, lack accessibility in low-socioeconomic regions of endemicity. New immunological procedures and nucleic acid storage, purification, and diagnostics protocols that are simple, rapid, accurate, and cost-effective must be developed as countries progress control efforts toward the elimination of the parasitic NTDs.

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.

Livestock guarding dogs have minor effects on the parasite burden of wild carnivores

Livestock guarding dogs are increasingly used to reduce carnivore-livestock conflicts, but no information is available to determine any adverse effects that these dogs may have on the health of wild carnivores. We assessed differences in prevalence, richness and severity of parasites in chilla fox (Lycalopex griseus) populations associated with livestock guarding dogs, which were routinely dewormed. We also evaluated whether the parasite assemblages of herding dogs, which were not dewormed, and chilla foxes were more similar in the presence of livestock guarding dogs. Scats of L. griseus and herding dogs were collected and screened for parasite eggs in areas with and without livestock guarding dogs to determine differences in prevalence, richness, intensity and parasite aggregation. We did not find any association between livestock guarding dogs and differences in parasite richness or prevalence of parasites. The intensity of parasites was higher among foxes positive to parasites when LGDs were present. A lower proportion of foxes with low parasite burdens occurred in areas with LGDs compared to areas without LGDs, but this difference was not significant at the population level. Our findings show the need to continue studying the effects of livestock guarding dogs on the health of wildlife with larger sample sizes and more locations.

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.

Evaluation of Hookworm Diagnosis Techniques from Patients in Debre Elias and Sanja Districts of the Amhara Region, Ethiopia

BACKGROUND

Inappropriate diagnosis could intimidate the prevention and control of hookworm infection. Thus, this study was aimed at evaluating the performance of hookworm diagnosis methods.

METHODS

An institution-based cross-sectional study was conducted from patients in Debre Elias and Sanja districts of the Amhara region, Ethiopia, from November 2019 to January 2020. The study subjects were selected conveniently. After the data was entered into Statistical Package for the Social Sciences (SPSS), sensitivity, specificity, predictive values, test accuracy, and agreement of the different hookworm diagnosis methods, namely, test tube flotation technique (TFT), McMaster (MM), formol-ether concentration (FEC), Kato-Katz (KK), and direct wet mount microscopy (DWMM), were calculated by using SPSS software. The composite reference standard (CRS) was used as the gold standard method. The kappa (κ) test was used to measure the level of agreement between diagnosis tests.

RESULT

A total of 389 stool samples were collected from patients in the study. The overall prevalence of hookworm was 63.24%. The test tube flotation technique (TFT) was found to be the highest both in terms of sensitivity and diagnostic accuracy (100%). McMaster (MM) was the second most sensitive test (68.7%), followed by FEC (44.3%) and KK (38.2%). On the other hand, DWMM had the lowest sensitivity (37.4%), and its diagnostic accuracy was also the least (60%). Only TFT had a perfect agreement (agreement = 100%, kappa = 1) with the CRS. The sensitivity of DWMM, KK, and FEC showed a kind of linear function with the intensity of infection, but TFT and MM methods were not affected by the infection intensity.

CONCLUSION

Hookworm is still a public health problem in the study area. TFT is by far more sensitive than MM, FEC, KK, and DWMM techniques.

Comparison between five coprological methods for the diagnosis of Balantidium coli cysts in fecal samples from pigs

Background and Aim:

Balantidium coli is a protozoan that can infect humans and non-human primates, being the domestic pigs the animals most affected by this parasite. This study aimed to compare the performance of five coprological methods for diagnosis of Balantidium coli cysts in fecal samples from pigs.

Materials and Methods:

From September to December 2019, 558 fecal samples were collected from the rectum of backyard pigs in the Bucaramanga metropolitan area, Colombia. The average age of the sampled animals was 3-4 months. Fecal samples collected were tested using the following coprological techniques: Direct examination with Lugol’s iodine solution, buffered saline, centrifugation/flotation and McMaster techniques, and Ziehl–Neelsen method.

Results:

The results indicate that B. coli cysts were diagnosed most frequently through direct examination with Lugol’s iodine solution (52.7% of the samples) followed by direct examination with a buffered saline solution (37.6%). Moderate concordance (k=0.41; p<0.05) was determined between direct method with Lugol’s iodine and buffered saline solution, McMaster and buffered saline (k=0.35; p<0.05), and centrifugation/flotation and buffered saline (k=0.28; p<0.05) showed a fair degree of concordance. The rest of the comparisons were classified as poor. The flotation techniques (centrifugation/flotation and McMaster) did not show good recovery of cysts.

Conclusion:

It is concluded that the most efficient method for diagnosing this parasitosis was to an association between direct examination with Lugol’s iodine solution and buffered saline.

First report of Babesia occultans in two symptomatic cows in Iran

This study reports the identification and first molecular characterization of Babesia occultans from naturally infected cows in Iran. Microscopic examination showed pyriform trophozoites, and ring-shaped merozoites (>2.5 μm) in Giemsa-stained blood smears obtained from two symptomatic cows in West-Azarbaijan province, Iran. PCR amplification of the partial 18S rRNA gene including the V4 hypervariable region were carried out on DNA extracted from blood samples. BLAST analyses of the partial 18S rRNA (approximately 400 bp) obtained from two cows revealed the presence of B. occultans and the detected sequences were identical to each other. Comparisons of the partial 18S rRNA sequence of the current isolate with other B. occultans sequences from Tunisia, South Africa, Turkey, Pakistan, and China confirmed the relation of the Iranian isolate to the species B. occultans. Sequence analysis of the obtained B. occultans showed 99.5-100% identity to the previously reported isolates. The sequences of B. occultans had 100% identity to a sequence obtained from ticks in Tunisia. This report is the beginning of a path to further research about B. occultans in vectors and reservoirs throughout Iran.

Prevalence and distribution of soil-transmitted helminth infection in free-roaming dogs in Bali Province, Indonesia

BACKGROUND AND AIM

Several free-roaming dogs can be easily found in the public areas of Bali. They go out in search of foods and friends and defecate everywhere. In general, these groups of dogs do not receive good healthcare from their owners and are generally threatened by some disease-causing organisms, especially helminths. This study was conducted to identify and measure the prevalence of soil-transmitted helminths (STHs) that cause infection in free-roaming dogs in Bali Province, Indonesia.

MATERIALS AND METHODS

A total of 1611 fresh dog fecal samples were collected from all areas of Bali Province and subjected to qualitative fecal examination using flotation techniques to obtain STH eggs.

RESULTS

The incidence of STHs in free-roaming dogs was 38.36%. However, three types of STHs were identified, including Ancylostoma spp., Ascaris spp., and Trichuris spp. Ancylostoma spp. had the highest prevalence of 37.8%, followed by Ascaris spp. and Trichuris spp. at 6.02% and 0.87%, respectively. Multiple infections of these worms were also recorded. The polyparasitism prevalence of Ancylostoma spp. and Ascaris spp. was 3.85%, followed by that of Ancylostoma spp. and Trichuris spp. at 0.5% and that of Ascaris spp. and Trichuris spp. at 0.06%. There were no altitude-wise differences in the prevalence of STH infection.

CONCLUSION

The prevalence of STHs was high in free-roaming dogs. This finding necessitates more serious attention as it affects both animal and public health.

Accuracy and precision of McMaster and Mini-FLOTAC egg counting techniques using egg-spiked faeces of chickens and two different flotation fluids

Faecal egg counting techniques (ECTs) are useful tools for assessing anthelmintic efficacy and selecting hosts resistant to parasite infection. McMaster (MM) is one of the most commonly used ECTs, but it suffers from low sensitivity and precision. Mini-FLOTAC (MF) has been proposed to replace MM, but so far has not been evaluated for gastro-intestinal nematode infections in chickens. This study compared sensitivity, precision, and accuracy of MM and MF with two trials using egg-spiked faecal samples ranging from 50-1250 eggs per gram of faeces (EPG). In addition, effects of two flotation fluids with different specific gravities (SG), namely salt (SG = 1.20) and sucrose solutions (SG = 1.32), on accuracy and time-spent for both ECTs were evaluated. Overall sensitivity based on the composite reads across all EPG-levels was 97.1 % for MM and 100 % for MF. MF was, however, more sensitive (P = 0.003) or tended to (P = 0.087) be more sensitive than MM at only the lowest EPG-level (i.e. 50 EPG) using one of the duplicate reads, whereas there was no significant difference at any EPG-level using composite reads. Overall average precision of MF (79.5 %) was higher (P < 0.001) than that of MM (63.4 %) across all EPG-levels. Precision of MM increased from 22 to 87 % with increasing EPG-levels from 50-1250 EPG. Corresponding precision estimates for MF ranged from 76 to 91 %. Overall recovery rate of MM (74.6 %) was significantly higher (P < 0.001) than that of MF (60.1 %). There was no significant difference in recovery rate of spiked-eggs among different EPG-levels (P = 0.833). Recovery rate of MM ranged from 64 % to 79 % across different EPG-levels, while it ranged from 54 % to 64 % with MF without an interaction between ECT and EPG-level (P = 0.701). It took more time (P < 0.001) to process (prepare and read) samples with MF than with MM using the same flotation fluid. The sugar solution tended to (P = 0.100) increase egg-recovery with both ECTs, while increasing (P < 0.001) time-spent for processing the samples. Our data collectively suggest that MM is less sensitive than MF only at around minimum detection level of MM when using unrepeated reads. We conclude that McMaster is faster, relatively more accurate but less precise than Mini-FLOTAC. The sugar solution with higher SG increases accuracy of both techniques at the expense of increased labour time.

Prevalence and risk factors associated with gastrointestinal parasites in ruminant livestock in the Coastal Savannah zone of Ghana

Gastrointestinal (GIT) parasite infections result in significant economic losses to ruminant livestock production. To determine the prevalence and risk factors associated with GIT parasite infections in livestock from Ghana, a cross-sectional survey was conducted in cattle and small ruminants kept under different management systems in the Coastal Savannah zone from October 2014 to February 2015. Faecal samples were collected from 328 cattle and 502 small ruminants (sheep and goats) and examined by formal ether concentration microscopy. The management systems and environmental conditions of the farm or household were observed, and a questionnaire administered to the livestock owners. Overall, 90.8% (754/830) of livestock were infected with at least one of ten different parasites (Eimeria, Strongylid nematodes, Toxocara, Trichuris, Schistosoma, Dicrocoelium, Paramphistomum, Fasciola, Moniezia and Thysaniezia), with Eimeria the most prevalent (78.4%). Most (64.5%) livestock had coinfections with two to five parasites with parasite intensity mostly light and at least one parasite was found in 98.6% (140/142) of the herds. Binary logistic regression models were generated to assess the risk factors associated with infection. Earthen floor was positively associated with strongylid infection, multiple ruminant species with Paramphistomum infection and flock size (>25 animal) with Thysaniezia, Dicrocoelium and Fasciola infections. Separating young animals from older animals was negatively associated with Strongylid infection, feed supplementation with Thysaniezia infection and small ruminant species with Paramphistomum and Toxocara infections. The findings from this study suggests that good sanitation, proper husbandry practices and improved nutrition can improve livestock health and production in Ghana.

Influence of intensive rearing, continuous and rotational grazing systems of management on parasitic load of lambs

AIM

A trial was conducted to assess the influence of parasitic load on the lambs reared under the intensive system, continuous grazing, and rotational grazing systems of management.

MATERIALS AND METHODS

A total of thirty numbers of the undetermined breed of ewe lambs around 4-5 months of age were randomly selected and allotted to three treatment groups: T1 (intensive system - control), T2 (rotational grazing), and T3 (continuous grazing). The T1 group lambs were raised under a stall-fed system of management, the T2 group lambs were grazed under rotational grazing strategy in four paddocks of plot-A, while the T3 group lambs were continuously grazed in plot-B.

RESULTS

At the end of the study, there was a highly significant difference (p=0.01) in the fortnightly strongyle egg count per gram (EPG) of feces among the lambs pertaining to the three treatment groups; the lambs in T3 had a higher strongyle EPG compared to T2 lambs. With regard to the overall reduction in EPG from the initial count, lambs under rotational grazing showed the maximum decrease of 54.52% compared to lambs under T3 (continuous grazing). There was a strong positive correlation noticed between the mean temperature of the day at each fortnight and the subsequent EPG at each fortnight with R2=0.87. There was a strong positive correlation noticed between mean FAMACHA© scores and the EPG with R2=0.84, R2=0.83, and R2=0.83 for T1, T2, and T3, respectively.

CONCLUSION

The grazing management with pasture rotation should be considered as a viable option for sustainable parasitic control in case of grazing-dependent livestock husbandry in India.

The recovery of added nematode eggs from horse and sheep faeces by three methods

BACKGROUND

Nematode infections in horses are widespread across the world. Increasing levels of anthelmintic resistance, reported worldwide in equine parasites, have led to the creation of programs for the control of nematodes based on faecal egg counts (FEC). To improve nematode egg counting in equine faecal samples and establish whether the matrix of equine faeces or the eggs affect the counts, the analytical sensitivity, accuracy and precision of Mini-FLOTAC (combined with Fill-FLOTAC), McMaster and Cornell-Wisconsin techniques were compared. Known numbers of eggs extracted from equine or ovine faeces were added to egg free ovine and equine faeces to give counts of 10, 50, 200 and 500 eggs per gram (EPG) of faeces.

RESULTS

The Cornell-Wisconsin significantly underestimated egg counts and McMaster showed a low analytical sensitivity, revealing 100% of sensitivity only for concentrations greater than 200 EPG. EPG values detected by Mini-FLOTAC did not differ significantly from expected counts at any level of egg density.

CONCLUSIONS

Mini-FLOTAC combined to Fill-FLOTAC which provides an accurate method of weighing without need for a balance and filtering out debris, could be used for FEC on the farm as well as in the laboratory.

Microbial community and ovine host response varies with early and late stages of Haemonchus contortus infection

The interactions between gastric microbiota, ovine host, and Haemonchus contortus portray the ovine gastric environment as a complex ecosystem, where all factors play a pertinent role in fine-tuning each other and in haemeostasis. We delineated the impact of early and late Haemonchus infection on abomasal and ruminal microbial community, as well as the ovine host. Twelve, parasite-naive lambs were divided into four groups, 7 days post-infection (dpi) and time-matched uninfected-control groups; 50 dpi and time-matched uninfected control groups were used for the experiment. Six sheep were inoculated with 5000 H. contortus infective larvae and followed for 7 or 50 days with their corresponding uninfected-control ones. Ovine abomasal tissues were collected for histological analysis and gastric fluids were collected for PH value measurements, microbial community isolation and Illumina MiSeq platform and bioinformatic analysis. Our results showed that Haemonchus infection increased the abomasal gastric pH (P = 0.05) and resulted in necrotizing and inflammatory changes that were more severe during acute infection. Furthermore, infection increased the abomasal bacterial load and decreased the ruminal microbiome. A 7-day infection of sheep with H. contortus significantly altered approximately 98% and 94% of genera in the abomasal and ruminal bacterial profile, respectively (P = 0.04-0.05). However, the approximate altered genera 50 days after infection in the ovine abomasal and ruminal microbiome were about 62% and 69%, correspondingly (P = 0.04-0.05) with increase in some bacteria and decrease in others. Overall, these results indicate that Haemonchus infection plays a crucial role in shaping stomach microbial community composition, and diversity.

Multi-drug resistant Haemonchus contortus in a sheep flock in Antioquia, Colombia

A sheep farm experiencing high lamb mortality and poor body conditions of ewes due to haemonchosis was tested for the presence of anthelmintic-resistant nematodes in August 2014. A fecal egg count reduction test was performed in Colombia on this farm and a DrenchRite® Larval development Assay (LDA) was shipped to the University of Georgia in the United States for resistance testing. The fecal egg count reduction test (FECRT) was conducted on 70 out of 500 animals allocated into five groups of 14 animals each: untreated control, albendazole (ABZ; 3.5mg/kg sc), ivermectin (IVM; 0.2mg/kg sc), moxidectin (MOX; 0.2mg/kg sc) and levamisole (LEV; 5mg/kg sc) plus triclabendazol/ivermectin (TBZ; 10mg/kg and IVM; 0.2mg/kg po). Individual fecal egg counts (FEC) using the modified McMaster technique and pooled larval cultures were performed 10days after anthelmintic treatment. Following 10days the initial results from the ABZ and IVM groups, 24 animals were treated twice with trichlorfon (TCF; 50mg/kg po) on days 0 and 6, and then checked for FEC on day 10. Mean differences in FEC before and after treatment were negligible (3 to 8% change) for the control, ABZ, LEV-TBZ and IVM groups. The MOX treatment resulted a mean FEC reduction of 76.7%, which was not-significant by t-test (p=0.08). The TCF treatment showed a mean FEC reduction of 42.3%, which was also not-significant (p=0.1). The DrenchRite® LDA was used to evaluate the resistance status to benzimidazole, levamisole, ivermectin and moxidectin on this farm. Coprocultures indicated that the predominant worm species was Haemonchus contortus (Colombia 94-100%) (UGA 77% H. contortus and 23% Trichostrongylus colubriformis). Resistance was evaluated for both H. contortus and T. colubriformis. The LDA results indicated high resistance to all 4 anthelmintics for both parasite species. The current study, together with similar surveys in 4 other Antioquian goat and sheep farms, confirms the presence of multi-drug resistant H. contortus to all three classes of anthelmintics in this region of Colombia.

Searching for ivermectin resistance in a Strongylidae population of horses stabled in Poland

BACKGROUND

There are no available studies describing the possible resistance of strongyles to ivermectin in horses in Poland. One hundred seventy three horses from nine stud farms from South-Western Poland were studied. The effectiveness of ivermectin was studied on the 14th day after ivermectin administration using the fecal egg count reduction test, and a long-term observation of the egg reappearance period was carried out. The fecal study was carried out using a modified McMaster method, which typically detects 20 eggs per gram of stool. The results were subjected to statistical analysis that enabled quantification of the eggs in the stool samples.

RESULTS

The study revealed high efficacy of ivermectin on the 14th day after administration without a shortening of the egg reappearance period.

CONCLUSION

The results indicate that strongyles resistance to ivermectin in Poland is not a serious problem.

Early and late gene expression profiles of the ovine mucosa in response to Haemonchus contortus infection employing Illumina RNA-seq technology

We conducted herein transcriptome sequencing of the ovine abomasal tissues using the Illumina HiSeq 4000 platform to segregate early and late H. contortus-infected sheep (7 and 50days post-infected groups, respectively) from the control naive ones. A total of 548, 357 and 7 were substantially induced genes in 7days post-infection versus uninfected-control group, 50days post-infection versus 7days post-infection (7dpi), and 50days post-infection (50dpi) versus uninfected-control group, respectively. However, a total of 301, 355 and 11 were significantly repressed genes between 7dpi versus uninfected-control group, 50dpi versus 7dpi, and 50dpi versus uninfected-control group, correspondingly. This indicates that H. contortus infection induced a more potent activation of abomasal gene expression in the early stage of infection as compared to the late stage. Seven pathways were annotated by Kyoto Encyclopedia of Genes, and Genomes pathway analysis accounted for the significant percentage in early H. contortus infection. This study shows for the first time that both galectin-11 and matricellular protein osteopontin are up-regulated in abomasal tissue after chronic H. contortus infection, while galectin-4 is specifically down-regulated in the early infection. Additionally, our results showed that the induction or repression of these molecules is likely to determine the infection progression.

A quality enhancement green strategy for broiler meat by application of turmeric (Curcuma longa) powder as litter amendment to affect microbes, ammonia emission, pH and moisture

 In multi-cultural Sri Lankan conditions, poultry meat is paramount importance in ensuring food security and improving nutrition. Issues as contact dermatitis and ammonia emission in broiler industry which caused by diminished litter parameters cause reduction of meat quality, profits and environmental conditions. Therefore use of Turmeric (Curcuma longa) (TM) powder as an antiseptic litter amendment at several application levels to enhance litter parameters with microbial demolition was attempted. Three months old broiler litter (2 kg) sample was taken and initial pH and moisture was determined. Turmeric was used to mix at levels of 0%, 1%, 3%, 5% and 8% (w/w). After mixing, 150 g of mixed litter was placed in container for each level of the 4 replicates, incubated for 5h and analyzed for Total Plate Count (TPC), Yeast and Mold Count (YMC), total Nematode Count (NC), ammonia emission, pH and moisture. Significant reduction (p <0.05) of total bacteria was seen (20%, 46%, 95% and 96%) when 1%, 3%, 5% and 8% applications of TM. The YMC reduction was also significant (p <0.05) (34%, 41%, 55% and 65%). Total nematode reduction (p <0.05) was 22%, 45%, 62.5% and 70%. A significant (p <0.05) pH reduction with increment of TM also seen (0.1, 2, 3 and 3%). Moisture (%) was increased (p <0.05) (6, 0.78, 19 and 1%). Ammonia emission was significantly decreased (p <0.05) by increased TM (64, 68, 73 and 84%) against control. It was concluded that the bacterial, fungal, nematode counts, pH and Ammonia emission of broiler litter can be significantly reduced with the application of 8% (w/w) of turmeric powder.

Repeatability of strongyle egg counts in naturally infected horses

The selective treatment of horses is used to decrease the number of anthelmintic treatments by only treating a proportion of animals in the population. One way to select animals for treatment is to identify low and high egg-shedders using faecal egg counts (FEC); then to treat only the high egg-shedders. The value of this method is enhanced if differences among individuals in the level of egg-shedding remain consistent over time. One way to assess the stability of the rankings of animals over time is to measure the repeatability which is defined as the variance between horses divided by the total variance. The repeatability varies between 0 (no consistency in the values) to 1 (perfect consistency). To determine the repeatability of egg-shedding in naturally infected horses over time, 2637 FEC and raw egg counts (REC; i.e. originally counted eggs without multiplication factor) from 303 horses were analysed. The distribution of FEC was more overdispersed than a Poisson distribution. Therefore, a negative-binomial model was used. The within-horse-repeatability of RECs was 0.52. In a second analysis, we excluded horses that were treated with anthelmintic drugs during the study by eliminating all REC within the egg-reappearance-period. Here, the within-horse-repeatability was very similar at 0.53. The results show that egg-shedding of individual horses stays fairly consistent over time. They also show that animals which shed relatively high numbers of nematode eggs can be identified and targeted for treatment.

Survey of gastrointestinal parasites, liver flukes and lungworm in feces from dairy cattle in the high tropics of Antioquia, Colombia

A cross sectional study was undertaken to determine the prevalence and intensity of parasitic infections in dairy cattle in the high tropics of Colombia. A total of 1003 rectal samples were collected from dairy cows at 29 farms between May and June 2014 to represent the number of farms, age groups, and size of the 65,000-cow population in the municipality of San Pedro de los Milagros. Coprological techniques were used to detect gastrointestinal nematodes, liver flukes, coccidian oocysts, and first larval stage counts of Dictyocaulus viviparus. In order of decreasing prevalence, the following parasites were detected: coccidial oocyst (36.7%; 95% CIs, 31.6–42.7), strongyle nematodes (31.6%, 27.8–35.4), liver flukes (30.9%, 21.5–37.5), cestodes (8.4%, 7.1–9.7), and D. viviparus (5.4%, 3.4–7.5). Co-infections by all possible combinations of the three most predominant groups occurred in 11 to 15% of the animals. There were significant differences in infection rates between age groups, with higher risk of liver fluke infection in animals older than 1 year of age (odds ratio (OR) = 3.2), but lower presence for coccidia and strongyles (OR = 0.19 and 0.51, respectively). For Fasciola hepatica, within-herd prevalences of > 25% in 16 farms and 94 of 281 (33.5%) animals with > 5 eggs per gram (epg) indicate that significant production losses are likely occurring. The variation in the prevalence of gastrointestinal parasites and liver flukes, together with the level of infection among age groups, could be used in integrated management programs to establish selective anthelmintic treatments and select for heritable traits of host resistance. These results serve as a baseline for future studies to determine the success of control measures and should increase awareness that subclinical parasitism is widespread in the livestock sector.

Diagnosis, Treatment and Management of Haemonchus contortus in Small Ruminants

Haemonchus contortus is a highly pathogenic, blood-feeding nematode of small ruminants, and a significant cause of mortalities worldwide. Haemonchosis is a particularly significant threat in tropical, subtropical and warm temperate regions, where warm and moist conditions favour the free-living stages, but periodic outbreaks occur more widely during periods of transient environmental favourability. The clinical diagnosis of haemonchosis is based mostly on the detection of anaemia in association with a characteristic epidemiological picture, and confirmed at postmortem by the finding of large numbers of H. contortus in the abomasum. The detection of impending haemonchosis relies chiefly on periodic monitoring for anaemia, including through the 'FAMACHA' conjunctival-colour index, or through faecal worm egg counts and other laboratory procedures. A range of anthelmintics for use against H. contortus is available, but in most endemic situations anthelmintic resistance significantly limits the available treatment options. Effective preventative programmes vary depending on environments and enterprise types, and according to the scale of the haemonchosis risk and the local epidemiology of infections, but should aim to prevent disease outbreaks while maintaining anthelmintic efficacy. Appropriate strategies include animal management programmes to avoid excessive H. contortus challenge, genetic and nutritional approaches to enhance resistance and resilience to infection, and the monitoring of H. contortus infection on an individual animal or flock basis. Specific strategies to manage anthelmintic resistance centre on the appropriate use of effective anthelmintics, and refugia-based treatment schedules. Alternative approaches, such as biological control, may also prove useful, and vaccination against H. contortus appears to have significant potential in control programmes.

Automated parasite faecal egg counting using fluorescence labelling, smartphone image capture and computational image analysis

Intestinal parasites are a concern in veterinary medicine worldwide and for human health in the developing world. Infections are identified by microscopic visualisation of parasite eggs in faeces, which is time-consuming, requires technical expertise and is impractical for use on-site. For these reasons, recommendations for parasite surveillance are not widely adopted and parasite control is based on administration of rote prophylactic treatments with anthelmintic drugs. This approach is known to promote anthelmintic resistance, so there is a pronounced need for a convenient egg counting assay to promote good clinical practice. Using a fluorescent chitin-binding protein, we show that this structural carbohydrate is present and accessible in shells of ova of strongyle, ascarid, trichurid and coccidian parasites. Furthermore, we show that a cellular smartphone can be used as an inexpensive device to image fluorescent eggs and, by harnessing the computational power of the phone, to perform image analysis to count the eggs. Strongyle egg counts generated by the smartphone system had a significant linear correlation with manual McMaster counts (R(2)=0.98), but with a significantly lower coefficient of variation (P=0.0177). Furthermore, the system was capable of differentiating equine strongyle and ascarid eggs similar to the McMaster method, but with significantly lower coefficients of variation (P<0.0001). This demonstrates the feasibility of a simple, automated on-site test to detect and/or enumerate parasite eggs in mammalian faeces without the need for a laboratory microscope, and highlights the potential of smartphones as relatively sophisticated, inexpensive and portable medical diagnostic devices.

A standardised faecal collection protocol for intestinal helminth egg counts in Asian elephants, Elephas maximus

The quantitative assessment of parasite infection is necessary to measure, manage and reduce infection risk in both wild and captive animal populations. Traditional faecal flotation methods which aim to quantify parasite burden, such as the McMaster egg counting technique, are widely used in veterinary medicine, agricultural management and wildlife parasitology. Although many modifications to the McMaster method exist, few account for systematic variation in parasite egg output which may lead to inaccurate estimations of infection intensity through faecal egg counts (FEC). To adapt the McMaster method for use in sampling Asian elephants (Elephas maximus), we tested a number of possible sources of error regarding faecal sampling, focussing on helminth eggs and using a population of over 120 semi-captive elephants distributed across northern Myanmar. These included time of day of defecation, effects of storage in 10% formalin and 10% formol saline and variation in egg distribution between and within faecal boluses. We found no significant difference in the distribution of helminth eggs within faecal matter or for different defecation times, however, storage in formol saline and formalin significantly decreased egg recovery. This is the first study to analyse several collection and storage aspects of a widely-used traditional parasitology method for helminth parasites of E. maximus using known host individuals. We suggest that for the modified McMaster technique, a minimum of one fresh sample per elephant collected from any freshly produced bolus in the total faecal matter and at any point within a 7.5 h time period (7.30am-2.55 pm) will consistently represent parasite load. This study defines a protocol which may be used to test pre-analytic factors and effectively determine infection load in species which produce large quantities of vegetative faeces, such as non-ruminant megaherbivores.

Diagnosis of human fascioliasis by stool and blood techniques: update for the present global scenario

Before the 1990s, human fascioliasis diagnosis focused on individual patients in hospitals or health centres. Case reports were mainly from developed countries and usually concerned isolated human infection in animal endemic areas. From the mid-1990s onwards, due to the progressive description of human endemic areas and human infection reports in developing countries, but also new knowledge on clinical manifestations and pathology, new situations, hitherto neglected, entered in the global scenario. Human fascioliasis has proved to be pronouncedly more heterogeneous than previously thought, including different transmission patterns and epidemiological situations. Stool and blood techniques, the main tools for diagnosis in humans, have been improved for both patient and survey diagnosis. Present availabilities for human diagnosis are reviewed focusing on advantages and weaknesses, sample management, egg differentiation, qualitative and quantitative diagnosis, antibody and antigen detection, post-treatment monitoring and post-control surveillance. Main conclusions refer to the pronounced difficulties of diagnosing fascioliasis in humans given the different infection phases and parasite migration capacities, clinical heterogeneity, immunological complexity, different epidemiological situations and transmission patterns, the lack of a diagnostic technique covering all needs and situations, and the advisability for a combined use of different techniques, at least including a stool technique and a blood technique.

Experimental estimation of the efficacy of the FLOTAC basic technique

The FLOTAC technique is a quantitative coproscopic method for the diagnosis of parasitic infection that is based on the centrifugation of a fecal sample to levitate helminth eggs with a flotation solution in a proprietary apparatus. Determination of the efficacy of the FLOTAC method and multiplication factors for calculation of the number of Toxocara, Trichuris, and Ascaris eggs in 1 g of feces on the basis of the number of detected eggs is presented. An investigation was conducted using feces samples enriched with a known number of parasite eggs: 3, 15, 50, or 100 parasite eggs of 3 nematode genera (Toxocara, Trichuris, and Ascaris) per 1 g (EPG) of feces. In addition, 80 samples of dog feces were prepared consisting of 20 repetitions for each level of contamination. The samples were analyzed using the FLOTAC basic technique. The limit of detection was calculated as the lowest level of egg content at which at least 50% of repetitions were positive. Multiplication factors for estimating the true number of parasite eggs in the samples were derived from regression coefficients that illustrated the linear relationship between the number of detected eggs and the number of eggs added to the sample. The percentages of recovered eggs for 1 chamber and for the whole apparatus ranged from 11.67 to 21.90% and from 21.33 to 40.10%, respectively, depending on dose enrichment and genus of parasite. The limit of detection calculated for the whole FLOTAC device was 3 EPG and was 15 EPG for 1 chamber for each of the 3 parasite genera. The limit of quantification calculated for whole FLOTAC was 15 EPG for each of 3 kinds of eggs. For 1 chamber, the limit of quantification was 15 EPG for Ascaris and Toxocara eggs and 50 EPG for Trichuris eggs. Multiplication factors for calculation of the number of eggs in 1 g of feces calculated for whole FLOTAC were 3 (for Toxocara and Ascaris eggs) and 4 (for Trichuris eggs). Experimentally calculated parameters of the method differ significantly from the theoretical assumptions of the authors of the FLOTAC technique and can significantly affect the reliability of the results. This does not alter the fact that the FLOTAC technique is the most effective parasitological quantitative method, which can be used to detect parasitic forms in feces. However, the results of our study emphasized the need for validation of the method before using it in the laboratory.

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.

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 contribution of simple random sampling to observed variations in faecal egg counts

It has been over 100 years since the classical paper published by Gosset in 1907, under the pseudonym "Student", demonstrated that yeast cells suspended in a fluid and measured by a haemocytometer conformed to a Poisson process. Similarly parasite eggs in a faecal suspension also conform to a Poisson process. Despite this there are common misconceptions how to analyse or interpret observations from the McMaster or similar quantitative parasitic diagnostic techniques, widely used for evaluating parasite eggs in faeces. The McMaster technique can easily be shown from a theoretical perspective to give variable results that inevitably arise from the random distribution of parasite eggs in a well mixed faecal sample. The Poisson processes that lead to this variability are described and illustrative examples of the potentially large confidence intervals that can arise from observed faecal eggs counts that are calculated from the observations on a McMaster slide. Attempts to modify the McMaster technique, or indeed other quantitative techniques, to ensure uniform egg counts are doomed to failure and belie ignorance of Poisson processes. A simple method to immediately identify excess variation/poor sampling from replicate counts is provided.

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).