Effects on haematological and serum biochemical parameters of Pangasianodon hypophthalmus to an experimental infection of Thaparocleidus sp. (Monogenea: dactylogyridae).

Monogenea (gill parasite) is a major problem in aquaculture that reduces the growth of cultured fish and adversely affects the economy. The present study was performed to evaluate the impact of various degrees of Thaparocleidus sp. (dactylogyrids, monogenean) infestation on haematological and serum biochemical parameters of Pangasianodon hypophthalmus. A standard cohabitation study, following complete randomized design in triplicate, was conducted to obtain low, moderate and high degrees of infestation in P. hypophthalmus along with the control (uninfested) group. Blood and serum were studied for haematological (total erythrocyte count (TEC), haemoglobin (Hb), packed cell volume (PCV), total leucocyte count (TLC) and indices viz. mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC) and erythrocyte osmolarity brittleness (EOB)) and serum biochemical parameters (serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lactate, total bilirubin and creatinine. Significant (p < 0.05) increase in TEC, Hb, TLC, EOB, SGOT, SGPT, LDH, lactate, bilirubin, and creatinine were noticed in moderate to high monogenean-infested group in comparison to the control group. However, significant (p < 0.05) reduction in MCH, and MCV and no difference (P > 0.05) in PCV were noticed in high degree parasitized group in comparison to the control group. The results of altered haematological and serum biochemical parameters in various degrees of monogenean-infested groups signify the density dependent physiological responses and changes in cells of the blood. The data of serum enzymes in the present study would be valuable for assessing the health status of the host and facilitate as a potential biomarker in relation to various degrees of monogenean infestation.

Transcriptional immune response of cage-cultured Pacific bluefin tuna during infection by two Cardicola blood fluke species.

Infections by two blood fluke species, Cardicola orientalis and Cardicola opisthorchis, currently present the greatest disease concern for the sea-cage culture of Pacific bluefin tuna (PBT) - a species of high global economic importance and ecological concern. In this study, we aimed to rapidly, quantitatively, and differentially identify infections by these two parasite species in cultured PBT as well as identify potential host immune responses. Using real-time qPCR, we were successful in quantitatively detecting parasite-specific DNA from within host blood, gill, and heart tissues; positively identifying parasitic infections 44 days earlier than microscopy methods previously employed. Both gill and heart became heavily infected by both parasite species in PBT within two months of sea-cage culture, which was only mitigated by the administration of anthelmintic praziquantel. Nevertheless, fish were observed to mount an organ specific transcriptive immune response during infection that mirrored the relative quantity of pathogenic load. In heart, significant (3-6 fold) increases in IgM, MHC2, TCRß, and IL-8 transcription was observed in infected fish relative to uninfected controls; whereas in the gills only IgM transcription was observed to be induced (11 fold) by infection. Interestingly, the relative quantity of IgM transcription was highly correlated to the relative abundance of C. orientalis but not C. opisthorchis DNA in the gill samples, even though this organ showed high prevalence of DNA from both parasite species. Taken together, these findings indicate that although ineffective at combating infection during primary exposure, a cellular immune response is mounted in PBT as a potential rejoinder to future Cardicola exposure, particularly against C. orientalis. Although future investigation into antibody effectiveness will be needed, this work provides valuable preliminary insight into host responsiveness to Cardicola infection as well as additional support for the need of anthelmintic treatment following primary parasite exposure during PBT culture.

[Morphological features of cellular responses to different rates of trematode: Quinqueserialis quinqueserialis (Trematoda: Notocotilidae) invasion in muskrat (Ondatra zibethicus)].

The results of investigation of leukocyte morphology and leukocyte contents of blood and caecum depending on the trematode Quinqueserialis quinqueserialis invasion rate in muskrats from natural population are given. At low trematode invasion rates, there was observed systemic activation of lymphopoiesis and neutrophil granulocytopoiesis with a decrease in the monocyte-miacrophage response in caecum (trematodelocalization organ). At the same time, under high invasion rates, there was detected induction of T cell suppressor activity and the absence of a granulocyte response in the tissues under study. Intensification of B lymphocyte blast transformation in caecum tissues as well as the appearance of blast cells in the blood of infected muskrats was observed.

Influence of ß-glucan on innate immunity and resistance of Lutjanus guttatus to an experimental infection of dactylogyrid monogeneans.

The present study investigated the effect of ß-1,3/1,6-glucan on growth, haematology, innate immunity and resistance against dactylogyrids on the spotted rose snapper (Lutjanus guttatus). Fish were fed during 5 weeks with commercial diet (control group) and same diet supplemented with three levels of ß-glucans (0·05%, 0·1% and 0·5%/kg feed). The results showed that at concentrations of 0·05% and 0·1%, fish growth was enhanced, and in weeks 2 and 4, an increase in cellular responses such as percentage of monocytes, neutrophils, respiratory burst activity and nitric oxide activity was observed. In diet with 0·5%ß-glucans, changes were registered at the end of the experiment. At week 2, 0·05%ß-glucans showed the best response to most of the analysed parameters. In a second trial, diet with 0·05%ß-glucans was chosen to prove its effect on the resistance of infected fish with monogeneans. The results showed that fish reduce significantly the number of dactylogyrids, and parameters such as WBC, percentage of lymphocytes, neutrophils and eosinophils were increased. In addition, WBC and percentage of thrombocytes increased in the control (+). The ß-glucans have the potential to be use in diet formulations of the spotted rose snapper and to limit the adverse effects of dactylogyrids.

Influence of Calicophoron microbothrium amphistomosis on the biochemical and blood cell counts of cattle.

Sixteen Tuli steers aged 1 year were subdivided into four equal groups (I-IV) and infected with Calicophoron microbothrium metacercariae. Group I received a low dose (LD) of 5000 metacercariae, group II a medium dose (MD) of 15,000 metacercariae, group III a high dose (HD) of 25,000 metacercariae while group IV was the non-infected control (C) group. The experimental animals were monitored daily for clinical signs while ethylene diamine tetraacetic acid (EDTA) blood and serum samples were collected every 7 days until day 28 post-infection, when sample collection was terminated. Samples were processed for full blood count, eosinophils and blood biochemical values for calcium, magnesium, phosphorus, total protein and albumin. Moderate to severe diarrhoea developed in the MD and HD groups at day 21 post-infection. The diarrhoea coincided with a significant decrease (P < 0.05) in total plasma protein, calcium and phosphorus levels, particularly in the MD group. Similarly, a significant decrease (P < 0.05) in the packed cell volume (PCV), the haemoglobin (Hb) and red blood cell (RBC) levels occurred in the MD and HD groups from day 21 post-infection, while a significant increase (P < 0.05) in the circulating eosinophils occurred between 7 and 21 days post-infection in the LD and the HD groups.

Glutathione-S-transferase: an important diagnostic antigen of liver amphistome Gigantocotyle explanatum, infecting the Indian water buffalo.

The foodborne trematodiases pose a significant health problem to the animals as well as the human population living in close proximities with the livestock and are still considered as the neglected tropical diseases by the World Health Organisation. The digenetic trematode, Gigantocotyle explanatum infecting the liver of Indian water buffalo, Bubalus bubalis, has been identified as one of the most common helminth parasite responsible for the disease, amphistomosis, in livestock. Despite huge abattoir prevalence, the epidemiological data and the actual economic losses incurred due to this parasite alone are yet to be established probably due to the limitations of routinely used diagnostic tests. The gold standard for the confirmation of such infections under field conditions is still the fecal egg count (FEC). However, the poor sensitivity and cumbersome nature of these tests necessitates the development of a more sensitive, reliable and easy to perform workflow/method. Immunological diagnosis of helminthic infections is still considered as an alternative to the FEC. Therefore, efforts have been made to utilize glutathione-S-transferase (GST), a vitally significant molecule of the adult G. explanatum, for the serodiagnosis of amphistomosis under both laboratory and field conditions. The GST antigen was first affinity purified from the somatic extract of the adult worms since its highest level was recorded in the somatic extracts followed by eggs and the excretory/secretory products. A five-fold affinity purified native GST antigen of about 25 kDa was found to be highly immunogenic as evident from high titre (1:25,600) of the polyclonal antibodies raised in the rabbits. The immunoblotting results revealed differential presence of GST in the adult worms, their eggs and excretory/secretory products. The immunolocalization studies revealed that the vitelline glands are the major source of GST in liver amphistome. Further, we were able to successfully screen animals naturally infected with G. explanatum using anti GST polyclonal antibodies in dot blot assay. High levels of both circulating GST antigen and anti GST antibodies were detected in the serum of the animals naturally infected with G. explanatum, while no cross reactivity was observed with the tropical liver fluke, F. gigantica which often infects the buffalo liver concurrently. The findings of the present study indicate that GST could be used as an important antigen for the diagnosis of G. explanatum infection in Indian water buffaloes.

[Increased accumulation of some trace elements in peripheral blood and bile of patients infested with Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1890)].

The invasion with Opisthorchis felineus (Rivolta, 1884) is known to be common in the Ob River region, West Siberia. These trematodes parasitize biliary tract of devinitive host (man or some species of animals). Other opisthorchiid species occurring in West Siberia, Metorchis bilis (Braun, 1890), has also been recorded recently as human parasite. Life cycles of both these trematodes include fish-eating mammal hosts. Eggs of O. felineus and M. bilis are very similar morphologically and can hardly be indentified. Chronic invasion with the helminthes is found to be a cause of disbolism of trace elements or high accumulation of some essential and toxic elements in the organism of definitive host. The aim of the present study was to determine concentrations of some essential and toxic elements in samples of peripheral blood and bile obtained from patients infested with Opisthorchis and/or Metorchis using instrumental neuron-activation technique. At first, all patients with microscopically confirmed opisthorchiasis (by microscopic examination of faeces and bile for the helminth eggs) were examined with serological method (ELISA) for specific anti-Opisthorchis and anti-Metorchis antibodies. Among 139 examined patients, 56.1% had specific antibodies against both Opisthorchis and Metorchis, 41.7% showed anti-Opisthorchis antibodies only, and 2.1% turn out to be seropositive for anti-Metorchis antibodies only. Of 31 elements detected in the samples of peripheral blood and bile, the concentration of nine essential and toxic elements (mercury, chromium, cesium, rubidium, lanthanum, bromine, selenium, zinc, and cobalt) in the patients with the mixt-infection of Opisthorchis and Metorchis (78 individuals) and with the Opisthorchis mono-infection (58 individuals) were significantly higher than those in healthy uninfested individuals. Among these elements, mercury and chromium showed the highest concentrations in infested patients. We suggest that the significant increase in concentrations of some toxic elements in blood and bile of patients may be associated with increased bioaccumulation of these elements in environment, especially in the local river water and fish. Moreover, concentrations of such elements as chromium, mercury, cesium, lanthanum, selenium, and zinc in blood and/or bile of the patients with mixt-infection of Opisthorchis and Metorchis were significantly higher than those in the patients with mono-infection of Opisthorchis. Accumulation of these elements in the organisms of patients was positively correlated with the number of parasites and the duration of helminth infection.

A novel Kunitz protein with proposed dual function from Eudiplozoon nipponicum (Monogenea) impairs haemostasis and action of complement in vitro.

Serine peptidases are involved in many physiological processes including digestion, haemostasis and complement cascade. Parasites regulate activities of host serine peptidases to their own benefit, employing various inhibitors, many of which belong to the Kunitz-type protein family. In this study, we confirmed the presence of potential anticoagulants in protein extracts of the haematophagous monogenean Eudiplozoon nipponicum which parasitizes the common carp. We then focused on a Kunitz protein (EnKT1) discovered in the E. nipponicum transcriptome, which structurally resembles textilinin-1, an antihemorrhagic snake venom factor from Pseudonaja textilis. The protein was recombinantly expressed, purified and biochemically characterised. The recombinant EnKT1 did inhibit in vitro activity of Factor Xa of the coagulation cascade, but exhibited a higher activity against plasmin and plasma kallikrein, which participate in fibrinolysis, production of kinins, and complement activation. Anti-coagulation properties of EnKT1 based on the inhibition of Factor Xa were confirmed by thromboelastography, but no effect on fibrinolysis was observed. Moreover, we discovered that EnKT1 significantly impairs the function of fish complement, possibly by inhibiting plasmin or Factor Xa which can act as a C3 and C5 convertase. We localised Enkt1 transcripts and protein within haematin digestive cells of the parasite by RNA in situ hybridisation and immunohistochemistry, respectively. Based on these results, we suggest that the secretory Kunitz protein of E. nipponicum has a dual function. In particular, it impairs both haemostasis and complement activation in vitro, and thus might facilitate digestion of a host's blood and protect a parasite's gastrodermis from damage by the complement. This study presents, to our knowledge, the first characterisation of a Kunitz protein from monogeneans and the first example of a parasite Kunitz inhibitor that impairs the function of the complement.

[Study of protein metabolism of herring gulls (Larus argentatus Pontop.) infected by trematode Himasthla larina (Trematoda: Echinostomatidae)].

The values and dynamics of some indices of protein metabolism were studied in herring gulls Larus argentatus infected with trematode Himasthla larina in natural populations and in experiment. These indices were compared in infected and uninfected birds. Trematode infection considerably affected host protein metabolism irrespective of the age; however, the changes were more pronounced in nestlings. Increased concentration of gamma-globulins, modified albumin, and circulating immune complexes was observed in plasma of infected herring gulls. The experiments demonstrated the most significant changes in protein metabolism of herring gulls 8-11 days after infection with trematode H. larina.

Clinical, hematological, biochemical, and ultrasonographic aspects of Platynosomum sp. (Trematoda: Dicrocoeliidae) infection of captive Callithrix penicillata.

Trematodes from the genus Platynosomum have been found to infect Neotropical primates in captivity, but little is known about their pathogeny in such hosts. This study evaluated the physiological effects of natural infection by the liver-dwelling trematode Platynosomum sp. in ten males and ten females of Callithrix penicillata kept in captivity at the Primate Center of the University of Brasília. The marmosets were examined twice, 6 months apart. The following parameters were analyzed: complete blood count, bleeding time, serum total protein, albumin, and the liver enzymes AST and ALT, and both a stool analysis and a liver ultrasonic evaluation were performed. We were able to characterize a group of abnormalities associated with this trematode infection which were mainly derived from the hepatitis caused by it: coagulation disorders, abnormal red blood cells, hypoalbuminemia, and abnormal levels of liver-linked serum enzymes. Eosinophilia and thrombocytopenia were also commonly seen. All of the aforementioned abnormalities were in good accord with typical effects of trematodes on liver parenchyma. We suggest that this set of abnormalities is characteristic of the infection of C. penicillata with Platynosomum sp., and should be among the most prominent aspects that the veterinary surgeon considers when suspecting such an infection. We also suggest that these clinical signs and abnormalities will be similar in other liver-dwelling trematode-infected primate species.

Partial characterization and isolation of 130 kDa antigenic protein of Dicrocoelium dendriticum adults.

The study focused on characterizing and isolating Dicrocoelium dendriticum antigens or their fractions that could be used for the immunological diagnosis of dicrocoeliosis. Somatic (SoAg) and excretory-secretory antigens (ESAg) were analyzed by SDS-PAGE and their specificity was evaluated by Western blot with homologous and heterologous sera. The antigens were partially purified by chromatographic techniques of gel-filtration (Sephacryl S-300) and ion exchange (Hitrap-DEAE-Sepharose). Western blot analysis using sera of ovine infected with D. dendriticum revealed eight main antigenic polypeptides ranging from 24 to 205 kDa for SoAg and seven for ESAg with apparent molecular mass in the range of 26-205 kDa. We detected a specific parasite protein with an approximate molecular weight of 130 kDa in SDS-PAGE gels, arranged as a 450 kDa tetramer in native conditions. It also showed strong immunoreactivity by Western blot against ovine sera experimentally infected with D. dendriticum. Gel filtration chromatography (Sephacryl S-300) also showed other specific proteins, one of about 24 kDa in SoAg and another of about 42 kDa in ESAg. The elution conditions of 450 kDa protein (130 kDa monomer) by DEAE chromatography were similar to those from the somatic antigen (pH 7.2, 0.1M NaCl, in 29-34 ml fractions) and from the excretion-secretion antigen (pH 8.0, 0.1M NaCl, in 29-35 ml fractions). The suitability of 130 kDa polypeptide for D. dendriticum infection diagnosis was confirmed by Western blot using a pool of sera as well as individual serum samples from experimentally infected sheep. The sequence of amino termini of 130 kDa polypeptide from both fractions was the same and identical to that reported for a peptide from D. dendriticum described as a globin. This sequence also revealed an appreciable similarity with the amino end of globins from some phylogenetically related worms.

[To the detection of the trematode mesocercariae Alaria alata in the blood of domestic dogs and cats].

Blood samples taken from 2128 domestic dogs and 543 cats in Moscow and the Moscow Region were studied by the concentration method using distilled water. The studies revealed the infestation with the mesocercariae Alaria alata in 1.9% of the dogs and in 1.I1% of the cats. A method was first developed for the life-time diagnosis of alariasis in definitive and reserve hosts.

Experimental Infections of Bluegill with the Trematode Ribeiroia ondatrae (Digenea: Cathaemasiidae): Histopathology and Hematological Response.

Infections by the digenetic trematode, Ribeiroia ondatrae, cause severe limb malformations in many North American amphibians. Ribeiroia ondatrae also infects fishes as second intermediate hosts, but less is known about the pathology and immune responses initiated in infected fish, even though reports of infected fish date back to early 1900s. To this end, we experimentally exposed juvenile Bluegills Lepomis macrochirus to three doses of R. ondatrae cercariae and monitored the pathology, parasite infection success, and humoral responses over 648 h. All exposed fish became infected with metacercariae, and the average infection load increased with exposure dose. Histologically, infection was associated with acute hemorrhages in the lateral line and local dermis at 36 h, followed by progressive granulomatous inflammation that led to the destruction of encysted metacercariae. Correspondingly, over the course of 648 h we observed an 85% decline in average infection load among hosts, reflecting the host's clearance of the parasite. Infection was not associated with changes in fish growth or survival, but did correlate with leukocytosis and neutrophilia in circulating host blood. Understanding the physiological responses of R. ondatrae in Bluegill will help to clarify the ecological effects of this parasite and provide a foundation for subsequent comparisons into its effects on behavior, individual health, and population dynamics of Bluegill.

Antibody response of definitive hosts against antigens of two life stages of the neuropathogenic schistosome Trichobilharzia regenti.

BACKGROUND: The nasal avian schistosome Trichobilharzia regenti spends part of its intravertebrate period of life within the central nervous system. Migration of the parasites can be accompanied by neuromotor disorders or paralysis in natural definitive hosts (ducks) and even in laboratory mammals. Cercariae are also able to penetrate human skin and induce cercarial dermatitis. While the cellular and antibody responses against cercariae and migrating schistosomula have been investigated in mice, little is known about immune reactions in birds. This study first describes the dynamics of antibody response in infected ducks and identifies frequently recognized antigens that may serve as diagnostic markers of infection by T. regenti. METHODS: Groups of 35 domestic ducks and 10 mallards were exposed to different doses of T. regenti cercariae. Sera were collected at predefined time intervals and tested by ELISA for the presence of specific anti-cercarial IgY and IgM. Antigens recognized by the antibodies were identified on Western blots of cercariae and schistosomula. The applicability in immunodiagnostics was statistically evaluated by expression of specificity and sensitivity values for individual antigens. RESULTS: In ELISA, the levels of anti-cercarial IgM peaked on day 15 pi. Increased production of IgY associated with the later phases of infection was observed in most individuals around 20 dpi and culminated 30 dpi. The time course of antibody response did not differ among experimental groups, variations were only observed in the levels of specific IgY which depended rather on the age of ducks at the time of infection than on the infectious dose. On Western blots, 40 cercarial and 7 schistosomular antigens were recognized by IgY from infected ducks. Among them, 4 cercarial antigens of 50, 47, 32 and 19 kDa provided the most sensitive and specific reactions. CONCLUSIONS: Antigens of cercariae and schistosomula elicited distinct antibody response in ducks, which correlated positively with the age of animals at the time of infection. Several antigens originating in cercariae and fewer in schistosomula were recognized by IgY with diverse sensitivity and specificity; only a few seemed to be common to both stages. Four of them were considered as the most promising candidates for immunodiagnostics.

Evaluation of an enzyme immunoassay for total IgE on a semi-automated analyser. A multicentre study.

Total serum IgE was measured by a semi-automated enzyme immunoassay on sera from normal and disease groups. Data from this investigation was analyzed in respect of precision, linearity, sensitivity and correlation with other test methods. Using human serum pools having values between 7 and 480 IU/ml, the intra-assay coefficient of variation ranged from 3.3 to 14.6% with an arithmetic mean of 6%. The inter-assay coefficient of variation on commercially supplied control sera ranged from 4.4 to 14.2%. In addition, tests were carried out on serially diluted samples to assess the linearity of the method, and on sera with IgE levels of less than 5 IU/ml in order to assess its sensitivity. It was shown that the technique being assessed was unaffected by the presence of lipid or haemoglobin or by the addition of bilirubin or any one of 46 commonly prescribed drugs each at double its toxic dose. There was good correlation between the semi-automated enzyme immunoassay technique and four other methods used during this study. This technique exhibits excellent specificity, reproducibility and a sensitivity well within clinical demands.

Navigation within host tissues: Schistosoma mansoni and Trichobilharzia ocellata schistosomula respond to chemical gradients.

After penetration of human or duck host's skin schistosomula of Schistosoma mansoni and Trichobilharzia ocellata migrate parallel to the surface in the epidermis, then they enter the dermis and venules prior to further migration. This study focuses on potential behavioural mechanisms and host cues which may enable this navigation within host tissues. We stimulated cercariae to penetrate into agar substrates and to transform to schistosomula, and analysed their orientation behaviour within chemical concentration gradients. Both species were chemotactically attracted by low molecular weight fractions of their host's serum (human, duck) and D-glucose and L-arginine were identified as attractive components in serum. They responded to gradients, which established after addition of very low concentrations of D-glucose (1 microM in T. ocellata and 2 microM in S. mansoni) and L-arginine (0.025 microM in T. ocellata and 1.0 microM in S. mansoni). The response to D-glucose was specific as other saccharides had no stimulatory activity. L-Arginine stimulated chemotactic orientation both when free and bound in peptides. However, the two species responded differently to the position of L-arginine within the peptide (terminal or subterminal), and only S. mansoni, not T. ocellata, responded to peptides occurring in serum and endothelial cells: fibronectin (1 microM), bradykinin (25 pM) and its fragment 1-5 (2.5 microM). Both species adjusted their body axis with the ventral side towards the higher concentrations of D-glucose and of L-arginine. We argue that the chemotactic orientation and the alignment of the body axis enable the parasites (i) to orientate towards deeper skin layers and avoid accidental perforation of the covering skin surface layers, (ii) to determine their position during their surface-parallel migration within the epidermis, (iii) to locate blood vessels.

Enzyme-linked immunoelectrotransfer blot analysis of excretory-secretory proteins of Fascioloides magna and Fasciola hepatica.

Fasciola hepatica is a parasite of cattle (Bos taurus), but not of white-tailed deer (Odocoileus virginianus), while Fascioloides magna is a parasite of white-tailed deer which also infects cattle as dead-end host. Adult parasites were collected from naturally infected white-tailed deer or cattle. Excretory-secretory proteins (ESP) were obtained from each parasite. Protein banding patterns were analysed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and probed using sera from experimentally infected deer of cattle using enzyme-linked immunoelectrotransfer blot (EITB, also known as Western blot) analysis. Protein banding patterns of the two species were different. EITB analysis of Fascioloides magna ESP using sera from Fascioloides magna infected deer or cattle identified three bands of approximately 17, 22 and 27 kDa of which the 27 kDa antigen cross-reacted with sera from Fasciola hepatica infected cattle. EITB analysis of Fasciola hepatica ESP probed with sera from Fasciola hepatica infected cattle identified three bands of approximately 15, 26 and 46 kDa. The 46 and 26 kDa ESP cross-reacted with sera from Fascioloides magna infected cattle, but not with sera from Fascioloides magna infected deer. The band at 15 kDa which reacted specifically for Fasciola hepatica infected cattle sera consisted of two protein bands close to each other as seen on the SDS-PAGE gel. The EITB reaction at approximately 17 kDa and 22 kDa of Fascioloides magna ESP, and at approximately 15 kDa of Fasciola hepatica ESP can be used for species specific diagnosis.

Response of leukocytes in chickens infected with the avian schistosome Austrobilharzia variglandis (Trematoda).

Leukocyte levels were monitored weekly in chickens infected with the avian schistosome Austrobilharzia variglandis. Changes in relative and absolute numbers of leukocytes were recorded over a 7-week period beginning 1 week before exposure. There was a significant increase (P less than 0.001) in total leukocytes, peaking at 5.8 X 10(4) cells/mm3 on day 21 postexposure; controls had 2.4 X 10(4) cells/mm3 on that day. The leukocyte count declined over the next 3 weeks, returning to nearly normal levels by day 42 postexposure. With the exception of eosinophils, which peaked 35 days postexposure, all leukocyte subpopulations peaked in number on day 21. Increases in heterophils and monocytes were related to the schistosome egg burden.

Hemolytic and coagulation properties of Sphaeridiotrema globulus (Trematoda).

Metacercariae of Sphaeridiotrema globulus (Trematoda) were obtained from naturally infected Goniobasis virginica (Pleuroceridae). Excysted metacercariae were placed individually on blood-agar plates. After 8 hr of incubation at 42 C the plates exhibited beta-hemolysis. The reaction zone was approximately 1.5 mm in diameter. Laboratory-reared mallard ducks (Anas platyrhynchos) were infected with S. globulus. Mallards developed fatal sphaeridiotremiasis and demonstrated increased prothrombin time on days 3 and 6 postinfection.