In vitro screening of 51 birdsfoot trefoil (Lotus corniculatus L.; Fabaceae) strains for anti-parasitic effects against Haemonchus contortus.

Secondary plant compounds have shown bioactivity against multi-drug resistant Haemonchus contortus in small ruminants. This study screened 51 strains of birdsfoot trefoil (BFT, Lotus corniculatus) crude aqueous extracts (BFT-AqE) for anti-parasitic activity in vitro against egg hatching, and of those 51 strains, 13 were selected for further testing of motility of first (L1) and third stage (L3) larvae, and exsheathment of L3. Proanthocyanidin content ranged between 1.4 and 63.8 mg PAC g-1 powder across the 51 BFT strains. When tested against egg hatching, 21 of the 51 aqueous extracts had an EC50 of 1-2 mg powder mL-1, 70% of the strains were >90% efficacious at 6 mg powder mL-1 and 11 of the strains were 100% efficacious at 3 mg powder mL-1 BFT-AqE. Across the 13 strains tested against L3, efficacy ranged from 0 to 75% exsheathment inhibition, and 17 to 92% L3 motility inhibition at a concentration of 25 mg powder mL-1 BFT-AqE. There was no correlation between the PAC content of BFT powders and the anti-parasitic activity of aqueous extracts, therefore other secondary compounds may have contributed to the observed anti-parasitic effects. Further testing of BFT using bioactivity-driven fractionation and screening of BFT populations for the identified anti-parasitic compounds is needed.

Risk factors and sources of foodborne hepatitis E virus infection in the United States.

Hepatitis E virus (HEV) is an important human pathogen with pigs and other species serving as natural animal reservoirs. Ample evidence documents sporadic cases of hepatitis E acquired via consumption of undercooked meat. Chronic hepatitis E cases in immunosuppressed individuals are mostly caused by zoonotic HEV of swine origin. We report here the identification of genotype 3 HEV from non-liver commercial pork from local grocery stores in southwest Virginia, and association of HEV seropositivity to the consumption of undercooked meat in healthy young adults at a university in the United States. These results raise concerns about foodborne HEV transmission in the United States. J. Med. Virol. 88:1641-1645, 2016. © 2016 Wiley Periodicals, Inc.

Retrospective study of canine endoparasites diagnosed by fecal flotation methods analyzed across veterinary parasitology diagnostic laboratories, United States, 2018.

BACKGROUND: Companion animal endoparasites play a substantial role in both veterinary medicine and public health. Updated epidemiological studies are necessary to identify trends in occurrence and distribution of these parasites, and their associated risk factors. This study aimed to assess the occurrence of canine endoparasites  retrospectively, using fecal flotation  test data available through participating academic veterinary parasitology diagnostic laboratories across the United States of America (USA). METHODS: Canine fecal flotation records from ten veterinary diagnostic laboratories located in nine states in the USA acquired from January 1, 2018, to December 31, 2018, were included. RESULTS: A total of 4692 fecal flotation test results were obtained, with a majority comprised of client-owned dogs (3262; 69.52%), followed by research dogs (375; 8.00%), and shelter dogs (122; 2.60%). Samples from 976 (20.80%) dogs were positive for at least one parasite, and co-infections of two or more parasites were found in 3.82% (179/4692) of the samples. The five most commonly detected parasites were: Giardia sp., (8.33%; 391/4692), Ancylostomatidae (5.63%; 264/4692), Cystoisospora spp. (4.35%; 204/4692), Toxocara canis (2.49%;117/4692), and Trichuris vulpis (2.43%; 114/4692). Various other internal parasites, including gastrointestinal and respiratory nematodes, cestodes, trematodes, and protozoans were detected in less than 1% of samples. CONCLUSIONS: These data illustrate the importance of parasite prevention, routine fecal screening, and treatment of pet dogs. Additionally, pet owners should be educated about general parasite prevalence, prevention, and anthelmintic treatment regimens to reduce the risks of environmental contamination and zoonotic transmission.

Biology, Epidemiology, and Control of Gastrointestinal Nematodes of Small Ruminants.

Strongylid gastrointestinal nematodes are an important cause of disease and economic loss in small ruminants. These parasites are important in most of the United States, with the bloodsucking parasite Haemonchus contortus being the predominant species of concern. Sheep and goats are infected while grazing, and the biology of infective larvae on pastures is important in the design of parasite management programs. Widespread resistance to anthelmintics requires strategies designed to preserve remaining drug activity; these include combination treatments with multiple classes of anthelmintics and targeted treatments.

Effect of birdsfoot trefoil cultivars on exsheathment of Haemonchus contortus in fistulated sheep.

Proanthocyanidin (PAC, condensed tannin) containing forages have well-documented anti-parasitic effects against gastrointestinal nematodes (GIN) of small ruminants. Although extensive research has been conducted on the inhibition of exsheathment of the L3 stage of Haemonchus contortus by in vitro exposure to the extracts of PAC containing plants, only one study has previously attempted to replicate this process in vivo and it was found that consumption of fresh sainfoin slowed the exsheathment rate. No similar studies have explored the effect of feeding condensed tannin forages in the form of hay on in vivo exsheathment of GIN. Another PAC containing forage, birdsfoot trefoil (Lotus corniculatus, BFT), has a large area of adaptation globally and feeding BFT has been shown to reduce fecal egg counts and total worm burdens. However, its effect on the in vivo exsheathment of H. contortus in the rumen is unknown. Recent work from this laboratory showed that BFT populations differ in the ability of aqueous extracts of freeze-dried plants to reduce exsheathment of H. contortus in vitro, and that the reduced exsheathment caused by BFT populations did not directly correlate with PAC content. Therefore, the objective of this study was twofold: 1) to evaluate the ability of birdsfoot trefoil hay to impair ruminal exsheathment of H. contortus in vivo and 2) to measure the difference in exsheathment between three commercially available cultivars of birdsfoot trefoil representing a broad range of in vitro efficacy against H. contortus. Four rumen fistulated ewes were fed three cultivars of birdsfoot trefoil (cv. Bruce, Empire, and Pardee) hay or a control hay (alfalfa/grass hay) in a Latin 4 × 4 design. The effect of consumption of birdsfoot trefoil on the exsheathment of H. contortus larvae in vivo was evaluated. For each exsheathment test, two capsules with 2000 ensheathed third-stage larvae per capsule were placed in the rumen of each ewe for eight hours. Larval containment capsules were made by capping each end of a short piece of Tygon® tubing (ID 9.5 mm, OD 14.3 mm) with an 8 µm NuncTM Cell Culture Insert. Larval exsheathment and motility were examined pre and post rumen exposure. Three exsheathment tests were run per diet cycle. Consumption of BFT hay did not significantly alter larval exsheathment. These results highlight the importance of further in vivo testing on the role of condensed tannins and other plant secondary compounds on larval exsheathment in the rumen.

Evaluating the relationship between fecal egg count, FAMACHA score, and weight in dewormed and non-dewormed Katahdin rams during a parasite challenge.

The objective of this study was to evaluate and to estimate the relationship between fecal egg counts (FECs) and FAMACHA score and the body weight of growing Katahdin rams during a parasite challenge. One of the largest factors negatively influencing reproduction and economics in the sheep industry is gastrointestinal nematode (GIN) parasites. Due to anthelmintic resistance of these parasites, animals are selected for parasite resistance using FEC and FAMACHA scores. Data were used from the Virginia Tech Southwest Agricultural Research and Extension Center Ram Test in Glade Spring, VA, from the year 2012 to 2018 in which animals were tested in 14-d intervals for 70 d. Mixed models for repeated weight measurements were made from backward stepwise selection to evaluate the relationships between weight and GIN FEC. A total of 576 animals within 23 contemporary groups derived from test year and pasture group were analyzed. Ram, contemporary group, and consignor were considered random effects, and fixed effects were birth type, test day, age, age squared, starting weight, FEC, and FAMACHA score. Pairwise contrasts were used in the statistical analysis of parameters and their interactions. Weight and age were found to have a quadratic relationship. Increased FEC was associated with weight loss at a rate of 0.00030 kg/FEC (P < 0.0001). Animals dewormed at any point during the trial weighed less than those that were not and increased with test day to a maximum difference of 4.66 kg (P < 0.001). FAMACHA score was found to be significant (P < 0.05), but a direct relationship with weight was not conclusive. Overall, rams with severe enough parasite load to require deworming had lesser weights, which could impact the profitability of sheep production and reinforced the need to select animals that had greater innate parasite resistance.

Gut microbial signatures associated with moxidectin treatment efficacy of Haemonchus contortus in infected goats.

Parasitic infections are associated with profound changes in the structure and function of the gut microbiome in various host-parasite systems. Here we examined the microbial composition and function in the abomasum, proximal colon and feces of Haemonchus contortus-infected goats after a partial anthelmintic drug clearance. A single-dose treatment of H. contortus-infected goats with Cydectin (moxidectin) resulted in an 83.9 % and 61.8 % reduction in fecal egg counts (EPG) and worm burden, respectively (P < 0.01), and restored abomasal pH to a normal baseline level. The treatment significantly increased the abundance of Proteobacteria, particularly that of Campylobacter, in the proximal colon. It also significantly affected several basic pathways, including bacterial secretion, butyrate metabolism, and LPS biosynthesis, and seemingly reduced the cellulolytic capacity in the colon. Several network modules displayed a strong correlation with EPG and worm burden. The Mantel test indicated a strong correlation between treatment related network topologies of the operational taxonomic units (OTU) belonging to Actinobacteria and Rikenellaceae and EPG and worm burden levels, respectively. Furthermore, microbial signatures that may better predict anthelmintic efficacy were identified. A signature or balance represented by the log ratio of the abundance of Verrucomicrobiaceae and Camplyobacteraceae had a strong correlation with EPG (r = 0.80). These novel insights into the interactions between H. contortus and gut microbiome in the caprine host and the consequence of a partial anthelmintic clearance on animal health and well-being may facilitate the design of more effective next-generation anthelmintics.

Giardia duodenalis assemblages in cats from Virginia, USA.

Giardia duodenalis is considered a species complex that is divided into 8 genetically distinct but morphologically identical assemblages (A-H). Assemblages C-H are generally host adapted, while A and B infect both people and animals and are considered potentially zoonotic. Furthermore, within assemblage A there are four subtypes (AI, AII, AIII, and AIV) of varying zoonotic potential; human isolates belong to AI and AII, while animal isolates belong to AI, AIII and AIV. Assemblages A, B, C, D, and F have all been reported from cats. The objective of this study was to determine the assemblage(s) of G. duodenalis present in cats from Virginia using multilocus genotyping and to assess if there were any differences among the assemblage(s) found in the populations of cats surveyed (free-roaming, shelter, owned) or their geographic location within Virginia. Samples that were positive for G. duodenalis cysts by microscopy using centrifugal flotation with ZnSO4 solution and/or direct immunofluorescence assay were genotyped using PCR and sequencing targeting fragments of the SSU rRNA, gdh, bg, and tpi genes. In total, 54 cyst-positive samples were analyzed by PCR and sequencing: 43 produced amplicons, and 37 samples had interpretable sequence data at one or more loci. Assemblage F was detected in 21/37 samples, AI was detected in 12/37 samples, and in 4/37 samples both assemblages F and AI were detected. The potentially zoonotic assemblage AI was detected in cats from two widely separated animal shelters and from one free-roaming cat. These genotyping data demonstrate that potentially zoonotic G. duodenalis assemblages are present in cats in Virginia.

Comparison of diagnostic techniques for detection of Giardia duodenalis in dogs and cats.

BACKGROUND: An evaluation of currently available in-clinic diagnostic tests for Giardia duodenalis infection of dogs and cats has not been performed. In addition, there is discordance among published diagnostic comparisons. The absence of a true gold standard for detecting Giardia duodenalis also complicates diagnostic evaluations. OBJECTIVES: To evaluate diagnostic tests commercially available in the United States for detecting Giardia duodenalis in dogs and cats, in comparison to a widely used reference test, the direct immunofluorescent assay (IFA), and also to compare the results of 2 methods of analysis: comparison of diagnostic tests to a reference test (IFA) and Bayesian analysis. ANIMALS: Fecal samples from a convenience sample of 388 cats and dogs located in Colorado, Oklahoma, and Virginia. METHODS: Fecal samples were tested for Giardia duodenalis by zinc sulfate centrifugal fecal flotation and 4 different commercial diagnostic immunoassays. Results were analyzed via Bayesian analysis and by comparison to the IFA as the reference test. RESULTS: Sensitivity and specificity by comparison to IFA was ≥82% and ≥90%, respectively, for all diagnostic tests in dogs and cats. When analyzed via Bayesian analysis, sensitivity and specificity were ≥83% and ≥95%, respectively. When ZnSO4 centrifugal fecal flotation results were combined with immunoassay results, there was no longer a significant difference between the sensitivities of the commercial in-clinic immunoassays. CONCLUSION AND CLINICAL RELEVANCE: The Bayesian analysis validates using IFA as the reference test. Differences in commercial in-clinic immunoassay sensitivities can be mitigated when the results are combined with ZnSO4 centrifugal fecal flotation results.

Evaluation of the mood-stabilizing agent valproic acid as a preventative for toxoplasmosis in mice and activity against tissue cysts in mice.

Toxoplasma gondii is a common intracellular protozoan infection of humans worldwide. Severe disease can occur in immunocompromised individuals and the in the fetuses of nonimmune pregnant women. Chronic infection is associated with vision and hearing problems, and functional mental alterations, including schizophrenia. The mood-stabilizing agent valproic acid has been shown to inhibit the development of T. gondii in vitro at dosages that are normally achieved in the serum and cerebral spinal fluid of human patients and to have positive effects on the behavior of rats chronically infected with T. gondii. The present study was done to examine the in vivo activity of valproic acid against acute toxoplasmosis in mice. Two studies were done with valproic acid given in the drinking water at concentrations of 1.5 mg/ml (Experiment 1) or 3.0 mg/ml (Experiment 2). In a third experiment (Experiment 3), valproic acid was injected intraperitoneally (i.p.) at doses of 200 or 300 mg/kg every 12 hr. Valproic acid was not effective in preventing acute toxoplasmosis. All mice treated with valproic acid died or were killed and did not (P > 0.05) live significantly longer than the controls. Tachyzoites were demonstrated in the tissues of infected valproic-acid-treated mice. A fourth study was done to determine if valproic acid has activity against T. gondii tissue cysts in chronically infected mice. Mice were chronically infected with the ME-49 strain of T. gondii for 8 wk and then treated orally with valproic acid at approximately 6.6 mg/ml (800 mg/kg/day) in the drinking water for 10 wk (amount was varied due to increasing mouse weights). No significant differences (P > 0.05) were present in tissue cyst numbers in valproic-acid-treated T. gondii chronically infected mice and in mice chronically infected with T. gondii but not given valproic acid. Our results indicate that valproic acid, although effective in vitro against T. gondii tachyzoites, is not effective as a preventative in mice inoculated with T. gondii tachyzoites. Additionally, no activity against tissue cysts was observed in chronically T. gondii-infected valproic-acid-treated mice.

Prevalence of anthelmintic resistance on sheep and goat farms in the southeastern United States.

OBJECTIVE: To determine prevalence of anthelmintic resistance on sheep and goat farms in the southeastern United States. DESIGN: Cross-sectional study. ANIMALS: Sheep and goats from 46 farms in 8 southern states, Puerto Rico, and St Croix in the US Virgin Islands. PROCEDURES: Parasite eggs were isolated from fecal samples, and susceptibility to benzimidazole, imidathiazole, and avermectin-milbemycin anthelmintics was evaluated with a commercial larval development assay. RESULTS: Haemonchus contortus was the most common parasite on 44 of 46 farms; Trichostrongylus colubriformis was the second most commonly identified parasite. Haemonchus contortus from 45 (98%), 25 (54%), 35 (76%), and 11 (24%) farms were resistant to benzimidazole, levamisole, ivermectin, and moxidectin, respectively. Resistance to all 3 classes of anthelmintics was detected on 22 (48%) farms, and resistance to all 3 classes plus moxidectin was detected on 8 farms (17%). CONCLUSIONS AND CLINICAL RELEVANCE: Findings provided strong evidence that anthelmintic resistance is a serious problem on small ruminant farms throughout the southeastern United States. Owing to the frequent movement of animals among regions, the prevalence of resistance in other regions of the United States is likely to also be high. Consequently, testing of parasite eggs for anthelmintic resistance should be a routine part of parasite management on small ruminant farms.

Prevalence of zoonotic parasites in feral cats of Central Virginia, USA.

Felis catus, the domestic cat, is the definitive host for parasites that may result in adverse health outcomes in humans. Prevalence data of zoonotic parasites in feral cats, which are free-roaming domestic cats that are born and live in the wild, are limited. The objective of this study was to assess seroprevalence of Toxoplasma gondii antibodies and copro-prevalence of potentially zoonotic parasites in feral cats and to evaluate risk factors for seropositivity and faecal excretion of parasites. In this cross-sectional survey, 275 feral cats at Trap-Neuter-Release clinics in Central Virginia were tested for parasites via faecal flotation, direct immunofluorescence assay (faeces) and modified agglutination testing (serum). Toxoplasma gondii seroprevalence was 22.35% (95% CI: 17.47-27.86). Faecal prevalence of T. gondii-like oocysts was 1.04% (95% CI: 0.13-3.71), Toxocara cati 58.85% (95% CI: 51.54-65.89), Ancylostoma spp. 18.75% (95% CI: 13.49-25.00), Giardia duodenalis 5.73% (95% CI: 2.89-10.02) and Cryptosporidium spp. 3.33% (95% CI: 1.37-7.24). Female cats were more likely than males to excrete faecal Ancylostoma spp. eggs (OR 2.88; 95% CI 1.34-6.17). Adults were more likely than immature cats to be seropositive (OR 2.10; 95% CI: 1.11-3.97) and to excrete faecal Ancylostoma spp. eggs (OR 2.57; 95% CI: 1.10-5.99). However, immature cats were more likely than adults to excrete T. cati eggs (OR 6.79; 95% CI: 3.31-13.90) and to excrete one or more potentially zoonotic species (OR 4.67; 95% CI: 2.28-9.55) in faeces. Results of this study have implications for human and animal health and highlight the importance of collaboration between public health, medical and veterinary communities in preventive efforts.

Anthelmintic efficacy of cranberry vine extracts on ovine Haemonchus contortus.

The discovery that plant secondary compounds, including proanthocyanidins (PAC), suppress gastrointestinal nematode (GIN) infection has provided promise for alternative methods of GIN control in small ruminants. This investigation is the first to examine the anthelmintic potential of cranberry vine (CV) against the GIN Haemonchus contortus. The purpose of this study was to explore the anti-parasitic activity of CV in the form of a specific organic proanthocyanidin extract (CV-PAC) and an aqueous extract (CV-AqE) containing PAC and other compounds. In vitro egg hatching, first (L1) and third (L3) stage larval and adult worm motility and L3 exsheathment were evaluated after a 24-h incubation with CV products. In addition, CV treated worms were observed via scanning electron microscopy, and a preliminary investigation of the efficacy of CV powder against an experimental infection of H. contortus was conducted. The in vivo effect on an experimental infection was determined by administering 21.1 g CV powder to lambs (n = 9 per group) for three consecutive days, and collecting fecal egg count data for four weeks post-treatment. The effect of CV-PAC on egg hatching, L3 motility and exsheathment was limited. However, a substantial effect was observed on motility of post-hatch L1 (EC50 0.3 mg PAC/mL) and adults (EC50 0.2 mg PAC/mL). The CV-AqE showed more effect on egg hatching (EC50 5.3 mg/mL containing 0.6 mg PAC/mL) as well as impacting motility of L1 (EC50 1.5 mg/mL with 0.2 mg PAC/mL) and adults (EC50 3.4 mg/mL with 0.4 mg PAC/mL), but like CV-PAC, did not substantially effect L3 motility or exsheathment. Scanning electron microscopy revealed an accumulation of aggregate on the cuticle around the buccal area of adult worms incubated in CV-AqE and CV-PAC. In the preliminary in vivo study, there was a significant effect of treatment over time (p = .04), although differences in individual weeks were not significant. In summary, both extracts inhibited motility of L1 and adult worms. The higher efficacy of CV-AqE than CV-PAC at levels that contained the same concentrations of PAC tested alone, suggest that other secondary compounds in the CV-AqE contributed to the observed effects on the parasites. This first study of the in vitro and in vivo effects of CV suggest that this readily available plant product may have utility in integrated control of H. contortus and support the need for additional testing to provide further information.

The effect of weaning method on coccidial infections in beef calves.

Weaning is often cited as a stressful event that can precipitate clinical coccidiosis in cattle. Recently, two-stage weaning methods have been investigated as a means to reduce stress in calves. The objective of this study was to investigate the effect of weaning method on fecal oocyst count (FOC) and Eimeria spp. composition. A group of 108 beef calves (190-240 days of age) were allocated to three treatments on day -7: a fenceline weaned group where calves could see and hear their dams, but were physically separated from them by a fence (FL), a noseclipped group where suckling was prevented (NC), and a group left with their dams to be traditionally weaned (TW) by abrupt separation on day 0. On day 0, noseclips were removed from the NC calves and all groups were completely separated from their dams. The steers (n=50) were transported 172 km to another farm, and heifers (n=58) were taken to distant fields on the same farm. Rectal fecal samples were collected from all calves on days -7, 0, and 14. Steers were also sampled on days 7, 28, and 42. A group of steers (n=24) from each of the treatments previously described were fitted with pedometers and intensively observed on days 1-4. The Modified McMaster's test and Wisconsin sugar flotation test were used for quantification and identification of Eimeria spp. oocysts. Clinical coccidiosis was not observed during the study. Fecal oocyst counts did not differ between treatment groups on any sampling day. Differences between steer and heifer FOC were not detected. Treatment had no effect on species composition, but time effects were detected in the steers. The mean percentage of E. bovis was lower (P<0.05) on days 28 and 42 than all other sampling days. The decrease in the percentage of E. bovis was accompanied by an increase (P<0.05) in the percentage of E. canadensis on days 28 and 42. Behavioral observation showed that TW steers exhibited higher levels of stress related behavior (P<0.05) following complete separation, although this was not reflected in FOC.

Cystoisospora canis Nemeséri, 1959 (syn. Isospora canis), infections in dogs: clinical signs, pathogenesis, and reproducible clinical disease in beagle dogs fed oocysts.

Canine intestinal coccidiosis is a cause of diarrhea in young dogs and dogs that are immunocompromised. Reports in the literature indicate that experimental reproduction of clinical coccidiosis with Cystoisospora canis (syn. Isospora canis) is difficult, and few studies have been done with C. canis. Experimental oral infections were attempted in 22, 6- to 8-wk-old female beagles with 5 x 10(4) (n = 2) or 1 x 10(5) (n = 20) sporulated C. canis oocysts. Diarrhea was observed in all inoculated dogs. Diarrhea began 2-3 days before oocyst excretion. Five of the 22 dogs were given an anticoccidial (sulfadimethoxine) because of their clinical signs. The mean prepatent period was 9.8 days (range, 9-11 days, n = 22 dogs), and the patent period was 8.9 days (range, 7-18 days, n = 20 dogs). Two dogs exhibiting clinical coccidiosis were examined at necropsy 10 days after infection. Developmental stages of C. canis were present in cells in the lamina propria throughout the entire small intestine in both dogs. Microscopic lesions observed in both of these dogs were villous atrophy, dilation of lacteals, and hyperplasia of lymph nodes in Peyer's patches. Results of bacterial and viral examinations of these 2 dogs were negative, indicating that intestinal coccidiosis was the cause of the diarrhea. Our study indicates that C. canis can be a primary cause of diarrhea in young dogs.

Flotation of Toxocara canis Eggs in Commercial Bleach and Effects of Bleach Treatment Times on Larval Development in These Eggs.

Toxocara canis is a common intestinal nematode of young dogs. Puppies contaminate the environment with large numbers of eggs that can embryonate and become infective in less than a month. Embryonated eggs are infectious for humans and other paratenic hosts. Most T. canis infections in humans are asymptomatic; however, migration of T. canis larvae in the eye and in the central nervous system can result in vision loss, blindness, and even death. The eggs of T. canis are highly resistant to harsh environmental conditions and routinely used chemical disinfectants. The objective of this study was to evaluate the effects of full-strength commercial bleach (5.25% sodium hypochlorite solution) treatment on development of T. canis eggs and to report our serendipitous finding that T. canis eggs in dog feces can float in passive fecal flotation tests using bleach. We also demonstrated that T. canis eggs could be identified using the McMaster's fecal eggs counting test using 100% bleach. Toxocara canis eggs collected from the feces of naturally infected 4-8 wk old puppies were treated with full-strength bleach (5.25% sodium hypochlorite solution) for 15 min, 30 min, 60 min, and 120 min; washed free of bleach smell by centrifugation; and resuspended in 0.1 N sulfuric acid solution to undergo larval development at room temperature for 18 days after exposure to bleach. Motile larvae were observed in T. canis eggs in all groups treated for 15-120 min and eggs continuously exposed to bleach for 18 days. Our results indicate that bleach may not be an appropriate disinfectant for dog kennels, cages, or laboratory utensils and work surfaces. Toxocara canis eggs are resistant to bleach treatment and continue to pose a risk for canine and human infections. Further study is needed to find the most appropriate methods for disinfection and removal of eggs to reduce the risk of transmission of this parasite.

Immunologic detection of Giardia duodenalis in a specific pathogen-free captive olive baboon ( Papio cynocephalus anubis) colony.

Several commercial Giardia immunoassays were evaluated in baboons for sensitivity and specificity as well as ease of use in a large specific pathogen-free (SPF) colony. An additional objective was to identify the assemblage(s) of Giardia duodenalis present in this baboon colony. A direct immunofluorescent antibody test (IFAT) was used as the reference test. Tests evaluated were a patient-side rapid test for dogs and cats, a human rapid test, and a well-plate ELISA designed for use with humans. Test sensitivities and specificities were compared using the McNemar paired t-test and were further evaluated for agreement using an unweighted Cohen kappa statistic. When compared to the IFAT reference, both human tests were more sensitive than the veterinary test. Based on PCR and sequencing of the G. duodenalis small-subunit ribosomal RNA and glutamate dehydrogenase loci, assemblage AI was present in this baboon colony. We found that 10 of the 110 (9%) baboons in this SPF colony were infected with a zoonotic strain of G. duodenalis.

Direct agglutination test for Encephalitozoon cuniculi.

Encephalitozoon cuniculi is a small protozoan parasite in the phylum Microspora. It has been shown to naturally infect several host species, including humans. Infection with microsporidia is usually asymptomatic, except in young or immunocompromised hosts. Currently, serological diagnosis of infection is made using the indirect immunofluorescent antibody assay (IFA) or enzyme-linked immunosorbent assay (ELISA). Although these methods are sensitive and reliable, there are several drawbacks to the IFA and ELISA tests. Cross-reactivity between other Encephalitozoon species is common, and specialized equipment is required to conduct these tests. This paper reports the development of a direct agglutination test for detecting IgG antibodies to E. cuniculi. The utility of the agglutination test was examined in CD-1 and C3H/He mice infected with E. cuniculi or one of 2 other Encephalitozoon species. Test sera were incubated overnight with eosin-stained microsporidia spores in round-bottom microtiter plates. In positive samples, agglutination of spores with antibodies in test sera resulted in an opaque mat spread across the well. The results indicate that the agglutination test is 86% sensitive and 98% specific for E. cuniculi, with limited cross-reactivity to Encephalitozoon intestinalis. No cross-reactivity to Encephalitozoon hellem was observed. The test is fast and easy to conduct, and species-specific antibodies are not required.

Prevalence of antibodies to Encephalitozoon cuniculi in horses from Brazil.

Encephalitozoon cuniculi has been associated with natural cases of abortion and stillbirth in horses. However, little is known about the prevalence of this parasite in horses. We examined sera from 559 horses from Brazil for antibodies to E. cuniculi using the indirect immunofluorescent antibody (IFA) test and the direct agglutination test (DAT). We found that 79 (14.1%) were positive in the IFA test and 70 (12.5%) were positive in the DAT. Compared to the IFA as the "gold standard" the sensitivity of the DAG was 94.0% and the specificity was 96.1%. Our study indicates that horses in Brazil are frequently exposed to E. cuniculi.

Gastrointestinal nematodes of small ruminants: life cycle, anthelmintics, and diagnosis.

Strongylid gastrointestinal nematodes are an important cause of disease and economic loss in small ruminants. These parasites are particularly important in the eastern United States where the bloodsucking parasite Haemonchus contortus is the predominant species. Sheep and goats are infected with gastrointestinal nematodes while grazing and the biology of the infective larvae on the pastures is important in planning effective control programs. Fecal egg counts can be used to monitor control programs and drug efficacy and evaluate levels of pasture contamination.