Freezing times and temperatures required to kill cysticerci of Taenia saginata in beef

Calves were given viable Taenia saginata eggs by stomach tube and slaughtered 12, 16 or 24 weeks later. The cysticerci-infected carcasses were frozen at six different temperatures for variable lenghts of time. Meat samples were then allowed to thaw at room temperature and the cysticerci were manually isolated. Criteria of viablity of the metacestodes were scolex evagination and peristaltic movements of the bladder wall. Sixteen and especially 12-week-old cysticerci were much more susceptible to the lethal effects of freezing than were 24-week-old cysticerci. The time and temperature combinations required to ensure death of all cysticerci were 360 h at ?5°C, 216 h at ?10°C, and 144 h at ?15°C or lower.     

Preferential infection sites of Cysticercus bovis in cattle experimentally infected with Taenia saginata eggs

The preferential sites of infection of Cysticercus bovis were evaluated in the skeletal muscle and entrails of 25 cattle that were experimentally infected with Taenia saginata (2 × 10⁴ eggs). Two other animals were not inoculated (control). Ninety days after inoculation, all the cattle were euthanized. The carcasses were deboned and dissected into 26 anatomical sections (masseter muscles, brain, tongue, esophagus, heart, diaphragm, lungs, liver, kidneys, spleen, top sirloin butt, bottom sirloin butt, outside round, top (inside) round, transversus abdominus, top sirloin cap, strip loin, full tenderloin, eye of round, knuckle, shoulder clod, foreshank, shank, chuck, back ribs, and tail muscles). The dissected tissues were sliced into 5 mm sections. From the 25 cattle, 9258 C. bovis (cysticerci) were recovered; 75.02% (6946) of these were recovered from skeletal muscles and 24.98% (2312) from the entrails. A high parasitism level was found in the shoulder clod (12.55%), heart (11.02%), liver (9.48%), masseter muscles (8.51%), chuck (8.25%), strip loin and full tenderloin (7.26%), knuckle (6.63%), and back ribs (5.53%), totaling 69.23% (5738) of all of the detected cysticerci. On the other hand, there was a low C. bovis parasitism level in the brain, spleen, tail muscles, kidneys, esophagus, and diaphragm, representing just 3.9% of the total number of cysticerci. Given these results, we conclude that specific skeletal musculature regions, such as the shoulder blade, chuck, strip loin and full tenderloin, knuckle, back ribs and top round, which are not officially examined in many countries, are effective sites to efficiently screen C. bovis infection. To date, these regions have not been considered as preferential sites of C. bovis infection. Based on our work, however, these regions deserve greater attention from health inspectors because they contained a greater number of Cysticercus than the other regions of carcasses that are parasitized by T. saginata larvae.     

Passive transfer of immunity to neonatal calves against the metacestodes of Taenia saginata

Passive transfer of immunity to neonatal calves against Taenia saginata was examined. Immune serum immunoglobulins were obtained from cattle inoculated orally with eggs of T. saginata, and from an animal which had been injected intramuscularly with eggs and activated oncospheres of the parasite. Immune colostral immunoglobulins were obtained by local injection of the mammary gland of a preparturient cow using activated oncospheres of T. saginata as antigen.Newborn calves fed the immune serum or colostral immunoglobulins were significantly protected against infection with T. saginata. In addition, more than 80% of the metacestodes in the protected calves showed evidence of degeneration, while only 34 and 27% of the metacestodes showed evidence of degeneration in those animals receiving “normal” control serum and “normal” control colostral immunoglobulins, respectively.     

Seroepidemiological study of Taenia saginata cysticercosis in Swaziland

A cross-sectional study of Taenia saginata cysticercosis in Swaziland using a serodiagnostic ELISA for parasite antigen is described. The seroprevalence and the levels of parasite antigen were compared in the sera of cattle from different geographical localities, and from areas of high or low population density. Cattle from the Lowveldt region, which has a hot and dry climate relative to the other areas investigated, exhibited significantly higher serum antigen levels. Seroprevalence was also higher in the Lowveldt but this difference was not found to be significant. Within the Lowveldt, antigen levels were found to be slightly elevated in cattle from more highly populated areas. It is suggested that either human behaviour and/or practices in animal husbandry, or increased susceptibility of cattle to reinfection at certain times of the year, may enhance transmission in the Lowveldt since climatic conditions in this region are not conducive to transmission.     

The antigenic activity of chromatographic fractions of a saline extract of Taenia saginata (Goeze, 1782) proglottides

A saline extract of a homogenate of Taenia saginata proglottides was partially purified by gel filtration chromatography on Sephadex G200 or Sepharose 4B and by ion exchange chromatography on DEAE cellulose. Gel filtration produced two distinct fractions with different antigenic properties. The first was of molecular weight of approximately 1,000,000 and contained a high level of activity in the haemagglutination inhibition test. The second fraction of molecular weigh of approximately 100,000 contained most of the immuno-precipitin activity. Other fractions had little or no antigenic activity. Eight fractions were obtained by DEAE cellulose chromatography, of which 4 had detectable antigenic activity. Subsequent rechromatography of fractions obtained by gel filtration on DEAE cellulose produced relatively pure fractions of high antigenic activity, from which small molecular weight contaminants had been removed.     

Comparative evaluation of immunoelectrophoresis,counterimmunoelectrophoresis and enzyme linked immunosorbent assay for the diagnosis of Taenia Saginata cysticercosis

The ante-mortem diagnosis of Taenia saginata cysticercosis remaining largely unresolved, the efficiency of immunoelectrophoresis (IEP), counterimmunoelectrophoresis (CIEP) and the enzyme linked immunosorbent assay (ELISA), has been compared. Of 32 experimentally infected cattle, these procedures could detect, respectively, 28, 30 and 31 of them. IEP and ELISA gave quite specific results whereas CIEP was relatively less specific.When applied on 24 proven cases of natural cysticercosis in conventionally raised cattle, harbouring relating light infections, IEP, CIEP and ELISA could detect, respectively, only 25, 54.2 and 37.5 per cent of the animals.On 100 slaughtered cattle, which were declared free of cysticercosis by the abattoir authorities, 3, 8 and 6 per cent of the animals showed flase positive reactions by the respective procedures. Evidence is presented that at least 2 of these false positive reactions were due to T. saginata metacestodes, which escaped detection by the abattoir authorities.These data show that noe of the serological tests discussed above are sufficiently reliable to make a diagnosis on an individual basis although these can be useful for a diagnosis on a herd basis.     

A comparison of the enzyme linked immunosorbent assay and the indirect haemagglutination technique applied to sera from cattle experimentally infected with Taenia saginata (Goeze, 1782)

The serological response of 6 calves to experimental oral infection with between 60,000 and 100,000 Taenia saginata eggs at 3–12 months of age was monitored by the enzyme-linked immunosorbent assay (ELISA) and the tanned cell indirect haemagglutination technique (IDH). A serum antibody response was detected by both techniques by 2–3 weeks post infection, rising to a plateau about 4–6 weeks post infection. The serum antibody levels began to decline by about 30 weeks post infection. Two uninfected control cattle gave negative reactions.In addition, the serological response of 5 calves which had received a dose of 10,000 T. saginata eggs at 2–3 days of age and then weekly serial doses of 500 eggs for 12 months thereafter, was compared with a similar group of 5 calves, which had received the single infection of 10,000 eggs at 2–3 days of age only. Calves in both groups developed an antibody response detectable by the ELISA technique whereas those in a group of 5 control calves did not show such a response. When studied individually however there was marked variation in the serum antibody levels of these young cattle, as although some calves gave a relatively strong serological response, others hardly varied from the controls.     

Age resistance and acquired immunity to Taenia pisiformis infection in dogs

An experiment was carried out using five groups of five beagle puppies each to measure age resistance to T. pisiformis infection and acquired immunity resulting from exposure to antigens released by adult tapeworms and/or oncospheres. Resistance was gauged by the number of worms established from challenge infections, and by the degree of development of those worms established (relaxed lenght, segment number, eggs per terminal proglottis).Age of puppies had a marked effect upon worm development, excluding the number of eggs per terminal proglottis, but not upon the number of worms established. Acquired immunity could not be demonstrated by any of the methods used.     

Cloning and characterization of a cathepsin L-like cysteine protease from Taenia pisiformis

Rabbit cysticercosis, caused by the larval stage of Taenia pisiformis, is a serious parasitic disease of rabbits. It was reported that some cysteine peptidases have potential roles in the pathogenesis of various parasitic infections. To investigate the biochemical characteristics and roles in the pathogenesis/host-invasion of cysteine peptidases, a cDNA sequence encoding for a cathepsin L-like cysteine protease (TpCP) was cloned and identified from the T. pisiformis metacestodes. This sequence was 1220 bp in its length, which included a 1017 bp open reading frame encoding a 339 amino acid peptide. Multiple sequence alignments revealed a 28.9–88.5% similarity with cathepsin L-like cysteine proteases from other helminth parasites and mammals. The recombinant TpCP expressed in Escherichia coli did not show the proteolytic activity by zymography gel assay. However, the TpCP expressed in Pichia pastoris had typical biochemical activities that could hydrolyze rabbit immunoglobulin G, bovine serum albumin and fibronectin. Substrate studies indicated pronounced cleavage of Z-Phe-Arg-AMC. This activity was sensitive to cysteine protease inhibitor E-64 and immunohistochemistry results also indicated that TpCP was distributed as an intense positive reaction in the bladder wall. Our results gave us insights into future studies of TpCP's roles in the infection.     

Micro ELISA and indirect haemagglutination tests in the diagnosis of Taenia hydatigena metacestode infections in lambs

Of 48 lambs slaughtered at a local abattoir, 60.4% were either found to be infected with Taenia hydatigena cycts, or showed evidence of abortive infections (white spots on the liver) with that parasite. The micro ELISA test and the IHA test did not distinguish between animals showing evidence of infection at slaughter and those which did not. Both tests gave results which correlated significantly with each other. The antigens used in the tests cross-reacted with each other, which may be the reason for the large number of false negative results.     

Resistance to Taenia pisiformis larvea in rabbits: Immunisation using live organism followed by chemotherapy therapy

Viable eggs or activated oncospheres of Taenia pisiformis were inoculated subcutaneously into rabbits. At various intervals the developing larvae were killed by treatment with Mebendazole. Most rabbits receiving oncospheres were protected against challenge infection if they were treated with Mebendazole 1 day after injection and absolute immunity was established in all rabbits if larvae were allowed to develop for 14 days before being killed. In rabbits receiving eggs, 21 days from injection to Mebendazole treatment was required before absolute immunity developed. Eggs appear to require a period of 1–2 weeks for hatching and oncosphere activation in a subcutaneous site. The data also indicate that production of functionally protective antigens occurs early during larval developement.     

Immunizing potential of various stages of Taenia ovis eggs injected subcutaneously into neonatal or sixteen-week-old lambs

When viable eggs of Taenia ovis were given orally to 1-week-old lambs, infection occurred only in those lambs that had been deprived of colostrum. When viable eggs were injected subcutaneously into 1-week-old lambs, no larvae developed at the injection site, and no resistance was stimulated against an oral challenge of T. ovis eggs given 11 weeks later. However, when eggs, oncospheres or developing cysticerci were subcutaneously injected into 16-week-old lambs, all grew at the injection site and stimulated a high degree of immunity to oral infection. Colostrum-derived antibodies against T. ovis apparently suppressed the immunizing potential of T. ovis eggs injected subcutaneously into neonatal lambs.     

Immunization of neonatal lambs against the larvae of Taenia hydatigena, using viable eggs followed by chemotherapy

The subcutaneous injection of viable eggs of Taenia hydatigena into neonatal lambs induced 100% protection against the development of viable T. hydatigena larvae from an oral challenge. However, contrary to some published results, no protection was induced against a simultaneous infection with eggs of T. ovis and Echinococcus granulosus.The short-acting partial resistance to oral infection with T. hydatigena eggs, transferred from infected ewes to their lambs, was not enhanced by hyperimmunization of the ewe. In the lamb, this resistance did not interfere with the development of subcutaneously injected T. hydatigena eggs into immature larvae, or with the consequent induction of resistance to an oral challenge with T. hydatigena eggs. The immunizing lesion regressed rapidly after treatment of lambs with Mebendazole, and after 6 months the lesions were negligible in both treated and untreated lambs.     

Antigenic and immunogenic studies on cell culture-derived Babesia canis

Babesia canis antigens derived from cell culture reacted specifically with immune serum from dogs convalescing from babesiosis. The antigens were heterogenous as compared to antigens elaborated in vivo. The major antigenic moiety from cell culture eluted in the first peak of Sephadex G-200 is indicative of a molecular weight around 900 000. In contrast, in vivo-derived antigen coeluted with albumin and hemoglobin suggesting a molecular weight of 67 000. The major antigenic mass is proteinacious and contains disulfide bonds as indicated by thermolability and sensitivity to 2-mercaptoethanol. Both particulate and soluble B. canis antigens were immunogenic, particularly when emulsified in Saponin as an adjuvant. Such antigens conferred a considerable degree of protection in susceptible dogs and it suggested that immunoprophylaxis to B. canis may be feasible.     

The influence of experimental Yersinia enterocolitica infection on the pregnancy course in sows--preliminary studies. III. Histopathological lesions

The aim of the study was to evaluate the anatomo- and histopathological lesions in internal organs of sows and their stillborn piglets after experimental Y. enterocolitica infection in different phases of pregnancy. Twelve pregnant sows were divided into 4 groups, infected per os on 33 (n = 3), 54 (n = 3) and 89 (n = 3) day of pregnancy with the pathogenic Y. enterocolitica strain isolated from the aborted swine fetus, and uninfected control group. Histopathological examinations of internal organs and intestine samples of stillborn piglets, slaughtered sows and samples of placentas were performed. Anatomo- and histopathological lesions were the most intense in the group of sows infected in the final phase of pregnancy, where the highest number of stillborn piglets was also found. Lesions of internal organs in stillborn piglets suggested a severe generalized bacterial infection. Although the analysis of experimental Y. enterocolitica infection of pregnant sows revealed that the most intense clinical, anatomopathological and histopathological abnormalities were recorded in the group of animals infected in the final phase of pregnancy. Infection in the first phase of pregnancy could have had an influence on the formation of the granulomatous inflammation. Differences in anatomopathological lesions between infected and control animals suggest that the period of pregnancy in which the infection appears could have had an influence on the course of yersiniosis in pigs.     

Potential diagnostic test for experimental and natural ovine Taenia hydatigena cysticercosis

An ion-exchange chromatographic fraction of Taenia hydatigena metacestode was evaluated for use in the immunodiagnosis of ovine cysticercosis. Analysis of the fraction by sodium dodecyl sulphate--polyacrylamide gel electrophoresis revealed the presence of a 68 KDa protein. Antibodies against the isolated protein were detected in 7 out of 10 experimentally infected lambs. The diagnostic potential of the 68 KDa protein was further confirmed by testing sera from naturally infected post-mortem positive (PM+) and from apparently healthy groups of animals. Eighty % and 8% of animals were found positive by enzyme-linked immunosorbent assay (ELISA) in the groups of PM+ and apparently non-infected lambs, respectively.     

Histopathological and immunohistochemical studies of apocrine sweat gland adenocarcinomas in cats

Seven adenocarcinomas of apocrine sweat glands among the 67cutaneous tumours of cats were evaluated between 1980 and 2005. Histopathologically, three tumours were solid, tubular, tubular‐ductal, tubular‐cystic and papillar‐cystic types were also diagnosed each one. Cuboidal and squamous epithelial cells surrounding the cystic lumina and their papillar extensions into the cyst lumens were evident in almost all tumour types. Besides, fibrovascular stroma which surrounding neoplastic foci showed proliferation and stromal invasion. Immunohistochemical features of these tumours were examined with pan‐cytokeratin, vimentin and carcinoembryonic antigen.