Suum Eggs Research Articles

OVOCIDAL ACTIVITY OF CYSTODEZ-ULTRA AGAINST ASCARIS SUUM EGGS IN AN IN VITRO LABORATORY EXPERIMENT

The ovocidal activity of various concentrations of Cystodez-ultra and the recommended concentration of Phenol was studied in an experiment on cultivation of Ascaris suum eggs in a thermostat at 26–28 oC in Petri dishes in a humid chamber for 30 days, in each of which 1000 eggs were placed. The first chamber was the control one, where the cultivation took place in saline. A solution containing 3, 4 and 5% concentration of the complex preparation Cystodez-ultra was introduced into the second, third and fourth chambers respectively. A 4% Phenol concentration was introduced into the fifth chamber. After a 24-hour exposure, Ascaris suum eggs were washed three times with distilled water, microscoped to find structural changes, and placed on cultivation. During egg cultivation, aeration was carried out once every two days, and embryogenesis was monitored. The viability of Ascaris suum eggs was determined by their appearance under light microscopy by staining and biological assay. The biological assay for experimental infection of white mice by administration of swine roundworm eggs after cultivation was carried out on 50 mice weighing 18–20 g, that were divided into five groups of 10 mice each. Mice of each group were kept isolated in cages and administered 200 Ascaris suum eggs through a plastic tube, which had previously been cultivated for 32 days and taken from groups 1–5. The complex drug Cystodez-ultra 3% in the in vitro experiment against Ascaris suum eggs showed 93.9% intense-effectiveness. The intense-effectiveness of the test drug in 4 and 5% concentration against swine roundworm eggs was 100%. The base drug Phenol 4% provided 88.8% intense-effectiveness. In the control group, 98% of A. suum eggs had the developed larvae inside. A bioassay on white mice confirmed the high efficacy of Cystodez-ultra against migrating roundworm larvae.

Host-Parasite Relationships in Porcine Ascariosis: Anticoagulant Potential of the Third Larval Stage of Ascaris suum as a Possible Survival Mechanism.

Simple SummaryAscaris suum parasitises pigs all over the world causing a disease responsible for producing reductions in weight gains and damages to several organs of the infected animals that incur huge economic losses for the swine industry. While adult worms of this parasite are located in the small intestine of the host, their larval stages migrate through the bloodstream as an evolutionary advantageous strategy within a hostile environment that confronts host responses such as blood clots formation. The aim of this work is to study the ability of A. suum larvae to inhibit blood coagulation as a possible mechanism to control blood clots formation and facilitate their migration. The results showed that these larvae inhibited host blood coagulation and possessed molecules similar to those responsible for inhibiting blood coagulation in pigs. The anticoagulant effect of A. suum larvae could constitute a potential survival mechanism for the parasite. Therefore, developing new control strategies directed at this and similar processes could avoid A. suum larval migration and the establishment of adult worms in their definitive location, which is necessary to confront the damages and economic losses produced by this parasitosis.In order to evade the response of their hosts, helminth parasites have evolved precise and highly regulated mechanisms, including migration strategies of the larval stages. In regard to porcine ascariosis caused by Ascaris suum, its infective third-stage larvae (AsL3) undergo a complex migratory route through the bloodstream of their host before establishing in the small intestine to reach maturation. Despite the benefits attributed to this migration, blood clots formation could compromise larvae survival. The aim of this work was to study the interaction between the cuticle and excretory/secretory antigens of AsL3 and the host coagulation cascade. Larvae were obtained after incubating and hatching A. suum eggs, after which the antigenic extracts were produced. Their ability to disrupt the coagulation cascade was studied using anticoagulation and chromogenic assays, and techniques based on electrophoresis. The obtained results showed that both antigenic extracts possessed anticoagulant potential, being able to inhibit the intrinsic, extrinsic and/or common pathways of the blood coagulation cascade as well as the activated factor X. Moreover, three A. suum serpin proteins were identified as candidates to inhibit this host coagulation factor. To the best of our knowledge, this study shows, for the first time, the anticoagulant potential of the infective larvae of A. suum, which could be used by the parasite as a mechanism to facilitate its invasion and survival in the host.

Parasites in Fresh Produce: a Brazilian Inter-laboratory Evaluation of a Standardized Methodology for the Detection of Ascaris sp. in Leafy Vegetables

Vegetables are potential vehicles for the transmission of parasites. Helminth eggs have been detected in produce in various countries around the world, with high prevalence rates. However, there is no standard validated method or ISO to the isolation, concentration, and identification of helminth eggs in salad vegetables, which makes comparison difficult since each study utilized different analytical methods and food matrix. The purpose of the present study was to evaluate the effectiveness of a previously described methodology developed for the recovery of Ascaris sp. eggs in two different leaf greens under real conditions of use, through the simultaneous application of the same method by ten different laboratories. This is the first collaborative inter-laboratory trial by several laboratories across Brazil. Lettuce and arugula samples artificially contaminated with A. suum eggs were analyzed by various laboratories to determine the recovery efficiency of Ascaris sp. eggs. A final mean recovery efficiency of 57.10% for Ascaris sp. eggs in lettuce and 50.7% in arugula was identified. The methodology applied in this study can be used to evaluate Ascaris sp. eggs in vegetables. It is reasonably easy, fast, and efficient in comparison with other methods. The identification of helminth eggs in fresh vegetables using a reliable methodology is important if the microbiological safety of these foods is to be improved.

Flotation solution influence on the quantification of Ascaris suum eggs in pig feces using McMaster technique

Parasitic diseases are responsible for economic losses in the pig production industry. It is necessary to monitor the parasite load through stool ova and parasite analysis to avoid losses to the producer. Among analytical tests, the McMaster technique is the most widely used method; however, several variations of this method have been described, and, therefore, there is a need for standardization. The aim of this study was to evaluate the use of different saturated solutions prepared from four different salts (NaCl, MgSO4, NaNO3, ZnSO4), a sugar solution, and Polysorbate Tween 80, to perform the McMaster technique. Pig feces containing Ascaris suum eggs were homogenized in Griffin beakers and divided into 2g aliquots for the exams with different solutions. All solutions evaluated were able to float A. suum eggs. However, eggs per gram of feces (EPG) values using the sodium nitrate solution were higher (p < 0.05) than for the other solutions. Magnesium sulfate and sodium chloride solutions provided intermediate values for EPG. Lower values were obtained with zinc sulfate and sugar solutions. Polysorbate Tween 80 was added to the sodium nitrate solution at a concentration of 0.2%, and this proved to be more efficient (p < 0.05) in flotation of the eggs.

S-Methyl-(2-Methoxycarbonylamino-Benzimidazole-5) Thiosulfonate as a Potential Antiparasitic Agent-Its Action on the Development of Ascaris suum Eggs In Vitro.

Ascaris suum is a soil-transmitted parasite causing ascariasis in pigs, largely limiting livestock production globally. Searching for new drugs affecting all stages of nematode development is necessary and widely postulated. The in vitro activity of S-methyl-(2-methoxycarbonylamino-benzoimidasole-5) thiosulfonate on A. suum developing eggs was studied. Five concentrations of the drug were used—0.625, 1.25, 2.5, 5 and 10 mM during 24, 48 and 72 h of exposure. After drug treatment, the eggs were washed and cultured in 0.05 M HCl at 27 °C for 20 days. Both the concentration and duration of the drug exposure had an inhibitory impact on the percentage of L2 larvae developed. The best effect was obtained after 72 h of incubation in 5 mM drug solution, only 1.9 ± 3.3% of the larvae developed to the L2 stage. Moreover, no SNP was detected at codon 167, which is correlated with benzimidazole resistance, in the tested samples. For the first time, it has been demonstrated that S-M-(2-MKA-BZ-5)TS seems to be a potential ovicidal anti-helminthic agent. It may lead to the elimination of parasites and reduce environmental contamination from roundworm eggs. The ovicidal effects of the drug should be additionally confirmed by further infection studies using experimental animals.

Parasitos gastrointestinais de suínos criados em uma granja em Nova Iguaçu, Rio de Janeiro

At the national level, there are several types of pig breeding that employ diversified technologies and management, depending on the financial conditions of each producer. This difference, evidenced in the productions, ends up reflecting the presence of infectious agents in animals, including infections determined by gastrointestinal parasites such as helminths and protozoa. Due to the lack of information and the importance of this topic, this study aimed to report, through a parasitological survey, the frequency of gastrointestinal parasites detected in pig raised on a farm located in the Nova Iguaçú city, Rio de Janeiro. For this purpose, 200 fecal samples from 40 pens were collected. Fecal samples were processed in a pool using the Lutz spontaneous sedimentation technique. In 100% of the samples, forms of parasites were detected, being mainly strongyles eggs (97.5%), followed by coccidia oocysts (87.5%), Balantioides coli cysts (75%), Strongyloides ransomi eggs (42.5%), Ascaris suum (25%) eggs and Trichuris suis (7.5%), with statistically significant differences between these frequencies. From the parasitological survey carried out, it was possible to identify a high frequency of parasites in the fecal samples of the animals, confirming that the pig farm had precarious conditions for sanitary management.

Deactivation of Ascaris suum eggs using electroporation and sequential inactivation with chemical disinfection

Abstract Electroporation has been evaluated as a potential backend wastewater treatment for deactivation of Ascaris suum eggs in buffer solution. Initial results indicate that eggshell permeability is affected by the pulse train electric field strength and duration. Coupling electroporation with chemical exposure, using low concentrations of commercially available disinfectants, allows oxidizing agents to pass through the complex strata of the A. suum eggshell, specifically reaching the innermost embryonic environment, which leads to successful deactivation compared to either method used separately. The aim of this work is to identify and develop an alternative technique that efficiently inactivates helminth eggs present in wastewater.

Inactivation of Ascaris for thermal treatment and drying applications in faecal sludge

Abstract Ascaris lumbricoides is the most common helminth of human health importance, and the most resilient helminth found in faecal sludge. There are numerous types of sludge treatments; however, heating and drying are most commonly used for pathogen inactivation. Ascaris suum eggs were heated in a water bath at 40–55 °C for 10 seconds to 60 minutes in water, as well as heated in both urine diversion dry toilet and ventilated improved pit latrine sludge at 40 °C, 60 °C and 80 °C for times ranging from 5 seconds to 120 minutes. Eggs were also spiked into sludges of different moisture contents and incubated over 12 weeks at 25 °C, with samples analysed weekly. Overall, we concluded that eggs were inactivated at temperatures &amp;gt;50 °C, that the temperature–time relationship directly impacted the efficacy of heat treatment, that suspension medium had no effect, and that eggs survived better in wet rather than dry sludges.

Study of disinvasive properties of innovative aldehyde disinfectant

The pollution rate of environment by pathogens of invasive diseases and contamination of manure, soil, water, and other objects by them are constantly changing depending on the prevalence and intensity of invasion among farm animals. Prevention and control of invasive animal diseases are essential to prevent their spread, as well as to obtain high-quality sanitary products for livestock production. The preservation of pathogens in the environment depends on the intensity of exposure to natural and artificial factors and their resistance to chemicals that are used for disinfection. A large number of disinfectants, both domestic and foreign, have been proposed for disinfection, but they are not always effective under industrial conditions for conducting forced or preventive disinfestation. The introduction of disinfectants into practice is impossible without a preliminary laboratory assessment of their disinvasive properties. The aim of our work was to study the disinvasive properties of a new aldehyde disinfectant on the test models of Ascaris suum eggs. The studies were carried out in the Laboratory of Veterinary Sanitation and Parasitology of the National Scientific Center ‘Institute of Experimental and Clinical Veterinary Medicine’ in accordance with the methodological recommendations ‘Methods to Identify and Evaluate Safety Parameters and Quality of Disinfectants, Detergent-Disinfectants Used During Production, Storage, Transportation and Sale of Products of Animal Origin’ (2010). As a result of the studies, it was found that the aldehyde disinfectant exhibits disinvasive properties to the test culture of Ascaris suum eggs when applied at a concentration of 4.0% at room temperature (18–20 ± 0.5°C) and exposure of 3 h. The disinfectant can be used for preventive and forced disinvasions of animal holding facilities and other veterinary control facilities

Pathogen Reduction Potential in Anaerobic Digestion of Organic Fraction of Municipal Solid Waste and Food Waste.

Anaerobic digestion (AD) is a commonly used method of processing waste. Regardless of the type of the used digestate (fertilizer, feedstock in case of solid-state fermentation, raw-material in case of thermal treatment) effective pathogen risk elimination, even in the case of high pathogen concentration is essential. An investigation of the survival time and inactivation rate of the Salmonella Senftenberg W775, Enterococcus spp., and Ascaris suum eggs during thermophilic anaerobic digestion performed on laboratory scale and confirmation of hygienization in full-scale operation were performed in this study. Except for sanitization efficiency, the AD process performance and stability were also verified based on determination of pH value, dry matter content, acidity, alkalinity, and content of fatty acids. The elimination of pathogen was met within 6.06 h, 5.5 h, and about 10 h for the Salmonella Senftenberg W775, Enterococcus spp., and Ascaris suum, respectively in the laboratory trials. The obtained results were confirmed in full-scale tests, using 1500 m3 Kompogas® reactors, operating in MBT Plant located in Poland. Sanitization of the digestate was achieved. Furthermore, the process was stable. The pH value, suspended solids, and ammonium content remained stable at 8.5, 35%, and 3.8 g/kg, respectively. The acetic acid content was noted between almost 0.8 and over 1.1 g/kg, while the concentration of propionic acid was noted at maximum level of about 100 mg/kg. The AD conditions could positively affect the pathogen elimination. Based on these results it can be found that anaerobic digestion under thermophilic conditions results in high sanitation efficiency.

Peran Ovicidal Herbal Serbuk Biji Pepaya (Carica papaya L) Matang Terhadap Telur Cacing Ascaris suum

An in vitro experiment to determine the effect of ground mature papaya seeds on characteristics of Ascaris suum eggs was conducted employing a Randomized Block Design. Four doses of the ground preparation – 0 mg (as control), 285 mg, 570 mg, and 855 mg- in 40 ml of physiological saline solution – were used to soak 100 eggs. Six replications were made. Worm eggs were obtained from the uteruses of ascariasis pigs slaughtered at the local abattoir. The eggs characteristics observed after application of the treatment were the embryo formation ability and the damage of egg cell layers. Statistical analysis was applied to the data collected using Analysis of Variance followed by Least Significance Test. The results showed that the ability of treated eggs to form embryos was significantly lower than that of control. Such a decrease in embryo formation ability could be related to the formation of granule (albumen coagulation) in the egg cell layers after the treatments. All treated eggs possessed such granules.

The Ovistatic Effect of Saprotrophic Soil Fungi on Ascaris suum Eggs

The aim of the study was to evaluate the potential use of selected species of soil fungi (Fusarium oxysporum, F. sulphureum, F. verticillioides, and Penicillium expansum) for the bioregulation of the dispersive stages of a parasitic nematode – the large roundworm of pig (Ascaris suum). Experimental cultures containing A. suum eggs with soil fungi and control cultures without fungi were incubated at 26°C for 28 days. Microscopic observations of the developmental stages of the A. suum eggs (zygote, 2-8 blastomeres, morula/blastula, gastrula, and larva) were performed at 7, 14, 21, and 28 days. The API-ZYM test was used to semi-quantitatively determine the activity of 19 hydrolytic fungal enzymes. The cytotoxicity of the fungi was determined with a tetrazole salt MTT assay. Microscopic observations of A. suum eggs incubated in the presence of fungi up to day 28 did not show any signs of destruction to egg shells and/or penetration of the fungi into the eggs. The ovistatic effect of all tested fungi (F. sulphureum, P. expansum, F. verticillioides, and F. oxysporum; p&lt;0.05) was seen only on the 7th day of incubation, whereas on the 14th day, only F. verticillioides and F. oxysporum showed an inhibitory effect on the embryogenesis of A. suum, and by the 28th day, only P. expansum. The API-ZYM test showed differences in the hydrolytic activity of the tested strains, while the MTT assay showed the high cytotoxicity of F. sulphureum, the moderate cytotoxicity of F. verticillioides and P. expansum, and the low cytotoxicity of F. oxysporum. Among the fungal strains studied, F. sulphureum showed the highest ovistatic effect, which may be related to its enzymatic activity and cytotoxicity.

Current time-temperature relationships for thermal inactivation of Ascaris eggs at mesophilic temperatures are too conservative and may hamper development of simple, but effective sanitation

Ascaris eggs are commonly used as indicators for pathogen inactivation during the treatment of fecal sludge and wastewater due to their highly resistant lipid membrane and ability to survive in the environment for long periods of time. Current guidelines suggest that thermal treatment alone cannot inactivate Ascaris eggs at temperatures below 45 °C, although some evidence in the literature suggests this to be incorrect. Here, we performed a controlled experiment to test the effect of mesophilic temperatures on Ascaris inactivation. We exposed Ascaris suum eggs to a temperature gradient between 34°C and 45 °C under anaerobic and aerobic conditions to observe the required exposure times for a 3-log reduction. Indeed, we found that temperatures lower than 45 °C did inactivate these eggs, and the required exposure times were up to two orders of magnitude shorter than suggested by current guidelines. Results from the anaerobic exposures were used to develop a time-temperature relationship that is appropriate for Ascaris inactivation at mesophilic temperatures. Data from the literature demonstrated that our relationship is conservative, with faster inactivation occurring under environmental conditions when Ascaris eggs were suspended in fecal sludge or manure. A specific aerobic relationship was not developed, but we demonstrated that aerobic conditions cause faster inactivation than anaerobic conditions. Therefore, the anaerobic relationship provides a conservative guideline for both conditions. We demonstrate that relatively low temperatures can considerably impact Ascaris viability and suggest that mesophilic temperatures can be used in waste treatment processes to inactivate pathogens. The development of safe, low-input, mesophilic treatment processes is particularly valuable for ensuring universal access to safe sanitation and excreta management.

The inactivation of Ascaris suum eggs by short exposure to high temperatures.

Ascaris sp. is the most prominent and resilient helminth of human health importance found in faecal sludge, making Ascaris sp. an ideal index organism for inactivation testing. Heat treatment destroys helminths,allowingfor safe handling and possible reuse of sludge. Technology developmentfocuses on rapid heating to minimize equipment size and cost. This study evaluates Ascaris suum eggs' viability with short heating time. Ascaris eggs were placed in a water bath at temperatures from 60 to 80 °C for various exposure times (5 seconds to 4 minutes) and were immediately processed and analysed via light microscopy. For all samples within these temperature and time ranges, less than 10% viable eggs were recovered. For 70, 75 and 80 °C, complete inactivation was observed for exposure time of 5 seconds and above.

IgG Induced by Vaccination With Ascaris suum Extracts Is Protective Against Infection.

Human ascariasis has a global and cosmopolitan distribution, and has been characterized as the most prevalent neglected tropical disease worldwide. The development of a preventive vaccine is highly desirable to complement current measures required for this parasitic infection control and to reduce chronic childhood morbidities. In the present study, we describe the mechanism of protection elicited by a preventive vaccine against ascariasis. Vaccine efficacy was evaluated after immunization with three different Ascaris suum antigen extracts formulated with monophosphoryl lipid A (MPLA) as an adjuvant: crude extract of adult worm (ExAD); crude extract of adult worm cuticle (CUT); and crude extract of infective larvae (L3) (ExL3). Immunogenicity elicited by immunization was assessed by measuring antibody responses, cytokine production, and influx of tissue inflammatory cells. Vaccine efficacy was evaluated by measuring the reductions in the numbers of larvae in the lungs of immunized BALB/c mice that were challenged with A. suum eggs. Moreover, lung physiology and functionality were tested by spirometry to determine clinical efficacy. Finally, the role of host antibody mediated protection was determined by passive transfer of serum from immunized mice. Significant reductions in the total number of migrating larvae were observed in mice immunized with ExL3 61% (p < 0.001), CUT 59% (p < 0.001), and ExAD 51% (p < 0.01) antigens in comparison with non-immunized mice. For the Ascaris antigen-specific IgG antibody levels, a significant and progressive increase was observed with each round of immunization, in association with a marked increase of IgG1 and IgG3 subclasses. Moreover, a significant increase in concentration of IL-5 and IL-10 (pre-challenge) in the blood and IL-10 in the lung tissue (post-challenge) was induced by CUT immunization. Finally, ExL3 and CUT-immunized mice showed a marked improvement in lung pathology and tissue fibrosis as well as reduced pulmonary dysfunction induced by Ascaris challenge, when compared to non-immunized mice. Moreover, the passive transfer of specific IgG antibodies from ExL3, CUT, and ExAD elicited a protective response in naïve mice, with significant reductions in parasite burdens in lungs of 65, 64, and 64%, respectively. Taken together, these studies indicated that IgG antibodies contribute to protective immunity.

Bifidobacterium animalis subspecies lactis modulates the local immune response and glucose uptake in the small intestine of juvenile pigs infected with the parasitic nematode Ascaris suum

ABSTRACTAn evaluation of a localized intestinal allergic type-2 response concomitant with consumption of probiotic bacteria is not well documented. This study investigated the effect of feeding probiotic Bifidobacterium animalis subspecies lactis (Bb12) or a placebo in weaned pigs that were also inoculated with Ascaris suum (A. suum) eggs to induce a strong Th2-dependent allergic type 2 immune response. Sections of jejunal mucosa were mounted in Ussing chambers to determine changes in permeability and glucose absorption, intestine and liver samples were collected for analysis of type-2 related gene expression, jejunum examined histologically, and sera and intestinal fluid were assayed for parasite antigen specific antibody. The prototypical parasite-induced secretory response to histamine and reduced absorption of glucose in the jejunum were attenuated by feeding Bb12 without a change in mucosal resistance. Parasite antigen-specific IgA response in the serum and IgG1 and IgG2 response in the ileal fluid were significantly increased in A. suum-infected pigs treated with Bb12 compared to infected pigs given the placebo. Ascaris suum-induced eosinophilia in the small intestinal mucosa was inhibited by Bb12 treatment without affecting the normal expulsion of A. suum 4th stage larvae (L4) or the morphometry of the intestine. Expression of genes associated with Th1/Th2 cells, Treg cells, mast cells, and physiological function in the intestine were modulated in A. suum infected-pigs treated with Bb12. These results suggested that Bb12 can alter local immune responses and improve intestinal function during a nematode infection by reducing components of a strong allergenic type-2 response in the pig without compromising normal parasite expulsion.

Devitalisation of pathogens in stored pig slurry and potential risk related to its application to agricultural soil

The study investigated the risks arising from application of pig slurry to soil in relation to viability of Salmonella typhimurium, Escherichia coli, total coliforms, faecal enterococci and eggs of Ascaris suum at different temperatures. Potential effect of changes in physico-chemical parameters, particularly dry matter (DM), pH and ammonia, were also investigated. Examination showed that S. typhimurium was devitalised after storage in the slurry for 115 days at 4 °C and after 90 days at 20 and 42 °C. Devitalization of E. coli and faecal entrerococci required more than 115 at temperature of 4 °C and faecal enterococci were recovered from slurry after 115 days of storage even at temperature of 20 °C. Total coliforms survived for 115 days at all investigated temperatures. Complete devitalization of A. suum eggs was not achieved even after 115 days at 42 °C. Our investigations indicated potential microbial and parasitic risk related to application of pig slurry to soil even after 115 days of storage.

Flavanol-Rich Cocoa Powder Interacts with Lactobacillus rhamnossus LGG to Alter the Antibody Response to Infection with the Parasitic Nematode Ascaris suum.

Consumption of the probiotic bacteria Lactobacillus rhamnosus LGG and flavanol-rich cocoa have purported immune modulating effects. This study compared the host response to infection with Ascaris suum in three-month-old pigs fed a standard growth diet supplemented with a vehicle control: LGG, cocoa powder (CP) or LGG + CP. Pigs were inoculated with infective A. suum eggs during Week 5 of dietary treatment and euthanized 17 days later. Lactobacillus abundance was increased in pigs fed LGG or LGG + CP. Specific anti-A. suum IgG2 antibodies were decreased (p < 0.05) in LGG + CP-fed pigs compared to pigs fed CP alone. Pigs fed LGG had significantly reduced expression (p < 0.05) of Eosinophil peroxidase (EPX), Interleukin 13 (IL-13), Eotaxin 3 (CCL26), Toll-like receptor 2 (TLR2), TLR4, and TLR9 and Interleukin-1Beta (IL1B) in the tracheal-bronchial lymph node (TBLN) independent of CP treatment. These results suggested that feeding LGG significantly reduced the localized prototypical Th2-related markers of infection with A. suum in the TBLN. Although feeding CP does not appear to affect the A. suum-induced Th2-associated cytokine response, feeding LGG + CP reduced anti-A. suum antibodies and delayed intestinal expulsion of parasitic larvae from the intestine.

Experimental &lt;i&gt;Ascaris suum&lt;/i&gt; infection in Yankasa lambs: Parasitological and pathological observations

The effects of experimental Ascaris suum infection in Yankasa lambs were investigated. Twenty four (24) Yankasa lambs aged 6-8 months were purchased and randomly divided into two groups (1 and 2). The lambs in group 1, consisting of 16 animals, were orally infected with 1500 infective A. suum eggs daily for seven consecutive days while those in group 2, consisting of 8 animals were maintained as non-infected/control group. All the experimental animals were closely monitored for 10 weeks, during which faecal samples were collected and analysed; and biochemical parameters of the blood samples were also evaluated. A total of seven animals (six from the infected and one from the control group) were humanely sacrificed on days 7, 14, 28 and 56 post-infection (p.i.) for larval/worm recovery, gross and histopathological examinations of organs. The values of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) from animals in the infected group increased significantly (P<0.05) on day 14 p.i. The animals from the infected group were observed to have a significant increase in the mean values of creatinine and urea on day 28 p.i. All liver samples from the sacrificed infected animals showed varying degrees of diffuse whitish areas of necrosis. Similarly, histopathology revealed different levels of mononuclear cellular infiltration in the liver of the sacrificed infected animals. In two of the infected animals, the kidneys were congested. By comparison, the corresponding organs from animals in the control group were normal. Eight (8) A. suum larvae were recovered from the lungs of one infected animal sacrificed on day 28 post-infection. However, no egg was detected in the faeces of the lambs. It is concluded, based on the findings of this study that A. suum is infective to Yankasa lambs but is only slightly pathogenic to the lambs and did not develop to patency. Keywords: Ascaris suum , Histopathology, Lambs, Larvae, Pathology

Evaluation of serology to measure exposure of piglets to Ascaris suum during the nursery phase

The aim of this study was to evaluate whether serology can be used to measure exposure of piglets to Ascaris suum during the nursery phase. Experimental infection studies were performed in which 7 groups of 10 piglets of 4 weeks of age were orally infected with either 10, 20, 40, 60, 80, 100 and 500 A. suum eggs/day during 7 consecutive weeks, mimicking a nursery phase in an A. suum contaminated environment. Serum was collected on a weekly basis to monitor seroconversion on 2 ELISA tests based on the antibody recognition of either a haemoglobin protein purified from the pseudocoelomic fluid of adult A. suum or a water-soluble complete homogenate of the 3rd stage larvae isolated from the lungs (L3-lung). A dose-dependent seroconversion was measurable with the L3-lung ELISA starting from 4 weeks post-infection onwards, whereas this was not measurable with the haemoglobin-based test. After 7 weeks, equivalent to the end of the nursery phase, the L3-lung ELISA showed a 99% specificity and a 90% sensitivity to detect exposure of piglets to A. suum, with a minimum infection level of 20 A. suum eggs per day. To further evaluate the test under field conditions, a seroprevalence study was performed by sampling 10 piglets on 68 different nursery farms in Belgium. The results showed that for 38% of the farms analysed all piglets tested seronegative, whereas for the remaining 62% of the farms the percentage seropositive piglets ranged from 10 to 100%. This indicates contamination of the nursery facilities with A. suum eggs. In conclusion, the outcome of this study shows that serology can be used to measure exposure of nursery piglets to A. suum, thereby providing an additional tool in the control of this widespread parasite.