76
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Schares G, Pantchev N, Barutzki D, Heydorn AO, Bauer C, Conraths FJ. Oocysts of , , and in faeces collected from dogs in Germany. Int J Parasitol 2005; 35:1525-37. [PMID: 16197949 DOI: 10.1016/j.ijpara.2005.08.008] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Revised: 08/10/2005] [Accepted: 08/17/2005] [Indexed: 11/21/2022]
Abstract
Faecal samples of 24,089 dogs were examined coproscopically in two veterinary laboratories in Germany between March 2001 and October 2004. In 47 dogs, oocysts of 9-14 microm size were found. Their morphology was similar to those of Hammondia heydorni and Neospora caninum. Samples of 28 of these dogs were further examined by inoculation into gerbils: seven isolates induced a specific antibody response against antigens of N. caninum NC-1 tachyzoites. This response suggests that the isolates contained N. caninum. In addition to H. heydorni (12 times isolated), Toxoplasma gondii occysts (twice) and Hammondia hammondi oocysts (twice) were observed in dog faeces. The latter findings suggest that coprophagia with a subsequent intestinal passage by dogs plays a role in the dissemination of coccidian parasites for which cats are definitive hosts. Five of the seven N. caninum (NC-GER2, NC-GER3, NC-GER4, NC-GER5, NC-GER6) and the two T. gondii isolates (TG-dgGER1, TG-dgGER2) were successfully passaged into cell culture and are now available for detailed characterization. In contrast to oocysts of other parasites, N. caninum oocysts were predominantly found between January and April (Fisher exact; P=0.038). In the sera of dogs shedding N. caninum, no reactions against the immunodominant antigens with apparent molecular weights of 19, 29, 30, 33 and 37 kDa of N. caninum tachyzoites were observed 3-5 weeks after shedding. However, the animals recognized a 152-kDa N. caninum antigen. Compared with those identified as H. heydorni, T. gondii or H. hammondi, N. caninum oocyst isolates were significantly smaller in length with the 75th percentiles <or=10.7 microm when measured in concentrated sucrose solution and smaller length-width ratios with the 75th percentiles <or=1.06. It may thus be possible to develop criteria for a preliminary identification of N. caninum in dog faeces based on the oocyst morphology.
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MESH Headings
- Animals
- Antigens, Protozoan/blood
- Base Sequence
- Coccidiosis/diagnosis
- Coccidiosis/immunology
- Coccidiosis/transmission
- Consensus Sequence
- Coprophagia/complications
- Coprophagia/parasitology
- DNA, Protozoan/analysis
- Disease Reservoirs
- Dogs
- Feces/parasitology
- Gerbillinae
- Germany
- Immunoblotting
- Interferon-gamma/genetics
- Intestinal Diseases, Parasitic/diagnosis
- Intestinal Diseases, Parasitic/immunology
- Intestinal Diseases, Parasitic/transmission
- Mice
- Mice, Knockout
- Molecular Sequence Data
- Neospora
- Oocysts
- Parasite Egg Count
- Polymerase Chain Reaction/methods
- Polymorphism, Restriction Fragment Length
- Seasons
- Toxoplasma
- Toxoplasmosis, Animal/diagnosis
- Toxoplasmosis, Animal/immunology
- Toxoplasmosis, Animal/transmission
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77
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Omata Y, Umeshita Y, Murao T, Kano R, Kamiya H, Kudo A, Masukata Y, Kobayashi Y, Maeda R, Saito A, Murata K. Toxoplasma gondii Does Not Persist In Goldfish (Carassius auratus). J Parasitol 2005; 91:1496-9. [PMID: 16539041 DOI: 10.1645/ge-3503rn.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Recent reports of toxoplasmosis in marine mammals raise concern that cold-blooded marine animals are a potential source of Toxoplasma gondii infection. To examine the transmissibility of T. gondii to fish, we observed the development of T. gondii tachyzoites inoculated into oviduct epithelial cells of goldfish (Carassius auratus) microscopically in vitro. Further, the survival period of tachyzoites inoculated into goldfish muscle was bioassayed in mice and through PCR analysis. In cell cultures at 37 C, both RH and Beverley strains of T. gondii tachyzoites had penetrated into cells at 6 hr post inoculation, and were multiplying. In cell cultures at 33 C, many tachyzoites of both strains attached to the host cells, but no intracellular tachyzoites were observed at 24 hr post inoculation. In the T. gondii inoculated goldfish kept at 33 C, tachyzoite DNA was detected in the inoculated region on day 3, but not on day 7. When inoculated goldfish were kept at 37 C, live tachyzoites were seen at the inoculation site on day 3, but not on day 7. These results suggest that T. gondii does not persist in fish.
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78
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Trees AJ, Williams DJL. Endogenous and exogenous transplacental infection in Neospora caninum and Toxoplasma gondii. Trends Parasitol 2005; 21:558-61. [PMID: 16223599 DOI: 10.1016/j.pt.2005.09.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 08/05/2005] [Accepted: 09/27/2005] [Indexed: 11/15/2022]
Abstract
It is clear from researching the vertical transmission of Neospora caninum in cattle that the terms 'vertical', 'congenital' and, indeed, 'transplacental' are inadequate for describing two extremely different situations that have fundamentally different immunological, epidemiological and control implications. A similar situation pertains to Toxoplasma gondii in different hosts. We advocate the use of the terms 'endogenous transplacental infection (TPI)' to define foetal infection from a recrudescent maternal infection acquired before pregnancy (and probably prenatally) and 'exogenous TPI' to define foetal infection that occurs as a result of an infection of the dam during pregnancy.
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79
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Locatelli-Dittrich R, Dittrich JR, Richartz RRTB, Gasino Joineau ME, Antunes J, Pinckney RD, Deconto I, Hoffmann DCS, Thomaz-Soccol V. Investigation of Neospora sp. and Toxoplasma gondii antibodies in mares and in precolostral foals from Parana State, Southern Brazil. Vet Parasitol 2005; 135:215-21. [PMID: 16289863 DOI: 10.1016/j.vetpar.2005.10.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 09/22/2005] [Accepted: 10/04/2005] [Indexed: 11/26/2022]
Abstract
Antibodies to Neospora sp. and Toxoplasma gondii were measured in mares and precolostral foals from a farm in Parana State, Brazil. An indirect fluorescent antibody test (IFAT) was used to determine specific antibodies. Three sampling points, 2003, 2004 and at parturition were included in the study, but not all horses are represented at a parturition time point. In 2003, antibodies to Neospora were detected in 17 mares (47%) at 1:50 dilution and in 5 mares (13.8%) at 1:100 dilution. In 2004, antibodies to Neospora were found in 11/36 (30%) horses with titers of 1:50 and in 6 mares (16.6%) at 1:100 dilution. The prevalence of antibodies against T. gondii was 2.7% in mares, either in 2003 and 2004. Evidence for the role of Neospora sp. in equine reproduction failure was not observed in the farm. Immunoglobulin G antibodies to Neospora were found in two of the nine precolostrum foals. Four seronegative foals were born from seronegative mothers, and three seronegative foals were born from seropositive mothers (1:50). Two seropositive precolostrum foals were born from seropositive mothers (1:50). The foals were born clinically normal, and T. gondii antibodies were not detected in their serum samples. The total immunoglobulins values detected on seronegative precolostrum foals were lower than the levels observed in the seropositive foals. This data warrants additional studies to differentiate N. hughesi and N. caninum serologically and determination if these parasites were associated with equine neurological disease and reproductive failure.
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80
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Brown M, Lappin MR, Brown JL, Munkhtsog B, Swanson WF. EXPLORING THE ECOLOGIC BASIS FOR EXTREME SUSCEPTIBILITY OF PALLAS' CATS (OTOCOLOBUS MANUL) TO FATAL TOXOPLASMOSIS. J Wildl Dis 2005; 41:691-700. [PMID: 16456157 DOI: 10.7589/0090-3558-41.4.691] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent efforts by North American zoos to establish a genetically viable captive population of Pallas' cats (Otocolobus manul) have been compromised by high newborn mortality (approximately 60%), primarily because of toxoplasmosis. The basis for this extreme susceptibility to toxoplasmosis is unknown. In the present study, the general health status of wild Pallas' cats in Mongolia was evaluated, including assessment of basal hematologic parameters and fecal corticoid metabolite concentrations. The prevalence of exposure to Toxoplasma gondii in Mongolian Pallas' cats, local domestic cats, and prey species also was determined based on serology and/or polymerase chain reaction analysis. Biologic samples (blood, feces, and/or brain tissue) were obtained from 15 wild Pallas' cats, 15 domestic cats, and 45 prey animals (rodents and pikas) captured in Mongolia during the summers of 2000 and 2001. Comparative data were obtained from nine captive Pallas' cats maintained in North American zoos. Based on physical examinations, complete blood counts, and blood chemistry analyses, only minor differences were observed in the general health status of wild and captive Pallas' cats. Fecal cortisol metabolite concentrations did not differ (P > 0.05) between populations, indicating that Pallas' cats in captivity and in the wild have similar basal adrenocortical activity. A pronounced difference (P < 0.01) in seroprevalence to T. gondii was observed between populations. Whereas all captive Pallas' cats exhibited elevated immunoglobulin titers (IgG > 2,048) to T. gondii, only two of 15 (13%) wild Pallas' cats were seropositive, with both cats having lower IgG titers (< 1,024). Furthermore, no evidence of exposure to this parasite was found in any of the Mongolian domestic cats or prey species. These findings suggest that wild Pallas' cats have minimal opportunity for exposure to T. gondii in their natural habitat and, typically, do not become infected with this parasite until being brought into captivity. Accordingly, maintenance of a viable captive population may require implementing effective strategies to prevent exposure of immunologically naive Pallas' cats to T. gondii and to reduce parasite transmission between seropositive females and their highly susceptible offspring.
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81
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Schulzig HS, Fehlhaber K. [Longitudinal study on the seroprevalence of Toxoplasma gondii infection in four German pig breeding and raising farms]. BERLINER UND MUNCHENER TIERARZTLICHE WOCHENSCHRIFT 2005; 118:399-403. [PMID: 16206928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
There are very few current data on the prevalence of Toxoplasma (T.) gondii in German pig farms. Consequently a reliable risk assessment of human Toxoplasmosis caused by ingesting raw or improperly cooked pork and pork products is not available. The aim of this study was to show current data on T. gondii prevalence in German pig farms. In four pig farms with different management systems (three conventional, one organic) 100 animals each were selected and tested for T. gondii antibodies. The test was done four times during the period from birth to slaughtering. In one farm 20 mother sows were tested additionally. The slaughtered pigs from conventional farms showed seroprevalences between 0 and 15.2% (mean value 5.6%). At the organic system T. gondii antibodies were not detected. All slaughtered seropositive pigs (6 months old) were tested negatively at the age of 9 weeks, but shortly after birth high titres of T. gondii antibodies had been detected in the same animals. Comparing the results gained in different seasons significantly more pigs were found to be infected during the autumn/winter than in the spring/summer period. In order to assess the current risk of Toxoplasmosis more pig farms should be tested. From the point of view of consumer protection the detection of highly infected pig herds is necessary.
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82
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Abstract
Atoxoplasma spp. (extraintestinal Isospora spp.) are coccidian parasites that infect a variety of passerine species. Atoxoplasmosis has been difficult to diagnose using buffy coat and organ impression smear examinations or histopathologic examination of tissues at necropsy. The prevalence of this parasite was studied in the tanager collection of a zoological park after the death of several tanagers from confirmed and suspected infections. A polymerase chain reaction assay was used to test blood, feces, or tissue samples (or all) from 88 individuals representing 18 species. Twenty-three of 60 (38.3%) blood samples from clinically healthy birds tested positive for Atoxoplasma, and one of six fecal samples was positive. Nineteen of 32 (59.4%) tissue samples from deceased tanagers tested positive. A total of 57 other institutions were also queried regarding the presence of Atoxoplasma. The high number of Atoxoplasma-positive clinically healthy birds suggests that the parasite is prevalent subclinically within tanager collections, with young birds and stressed adults being the most likely to develop clinical disease. Thorough disinfection of enclosures, consideration of enclosure designs, and preventing fecal contamination of food and water are important methods of decreasing transmission. Selective breeding programs and regular screening of breeding pairs may be recommended to decrease transmission to susceptible offspring. Care should also be taken when housing tanagers in mixed species or in outdoor enclosures because the transmission risks between species have not been well established.
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83
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Araujo FG, Remington JS. Effect of clindamycin on acute and chronic toxoplasmosis in mice. Antimicrob Agents Chemother 2005; 5:647-51. [PMID: 15825419 PMCID: PMC429028 DOI: 10.1128/aac.5.6.647] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effect of clindamycin on survival of mice during acute infection with the RH and C56 strains of Toxoplasma and the ability of this drug to prevent congenital transmission during the acute stage of the infection in the mother and to eradicate the parasite from tissues of mice chronically infected with the C56 strain were evaluated. The drug effectively prevented death due to the acute infection and, in the experimental model employed, eradicated the organism at least from the liver, spleen, and brain of approximately 30 to 50% of the acutely infected animals which survived. Clindamycin also effectively prevented congenital transmission during the acute infection in the mother. During short-term treatment (7 days), persistent parasitemia in the chronic infection was effectively diminished or eradicated. More prolonged treatment resulted in a significant clearing of the organisms from the spleens and livers, but not from the brains, of chronically infected mice.
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84
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Morley EK, Williams RH, Hughes JM, Terry RS, Duncanson P, Smith JE, Hide G. Significant familial differences in the frequency of abortion and Toxoplasma gondii infection within a flock of Charollais sheep. Parasitology 2005; 131:181-5. [PMID: 16145934 DOI: 10.1017/s0031182005007614] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27 families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since 1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. A total of 155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging between 0% and 48% (P<0·01). Significantly different infection frequencies with T. gondii were also observed for different families and ranged between 0% and 100% (P<0·01). Although the actual cause of each abortion was not verified, a highly significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection in the same families (P<0·01). The data presented here raise further questions regarding the significance of congenital transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods in the future.
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85
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Deyab AK, Hassanein R. Zoonotic toxoplasmosis in chicken. JOURNAL OF THE EGYPTIAN SOCIETY OF PARASITOLOGY 2005; 35:341-50. [PMID: 15881017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Modified agglutination test (MAT) was applied to 150 chicken sera (90 were farm-bred and 60 house-bred chickens). The prevalence of Toxoplasma antibodies was 18.7%. In house-bred chickens positive cases were 18 out of 60 (30.0%), while in farm-bred chickens positive cases were 10 out of 90 (11.1%). Histopathological sections of the seropositive chickens showed tissue lesions which were most likely to be induced by T. gondii. Tissue cysts of T. gondii were demonstrated in the liver, brain, heart and skeletal muscles of 22 (78.6%) out of 28 positive chickens. These tissue cysts were found mostly in the brain of seropositive chickens. Epidemiological implications of these data for public health significance were discussed.
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86
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Basso W, Edelhofer R, Zenker W, Möstl K, Kübber-Heiss A, Prosl H. Toxoplasmosis in Pallas' cats (Otocolobus manul) raised in captivity. Parasitology 2005; 130:293-9. [PMID: 15796012 DOI: 10.1017/s0031182004006584] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Manuls or Pallas' cats (Felis manul, syn. Otocolobus manul) are endangered wild cats from Central Asia kept and bred in many zoos. Despite good breeding success young cats frequently die from acute toxoplasmosis. From 1998 to 2002, a breeding pair in the Schönbrunn Zoo in Vienna, Austria, gave birth to 24 kittens; 58 % of kittens died between the 2nd and the 14th week of life, mostly due to acute toxoplasmosis. The epidemiology of toxoplasmosis in Pallas' cats was examined and a control strategy to protect the kittens from fatal toxoplasmosis was developed. One 12-week-old kitten from a litter of 6 born in 2001 died of generalized toxoplasmosis. This kitten had shed T. gondii oocysts that were bioassayed in mice. Toxoplasma gondii was isolated in tissue culture inoculated with tissues of these mice. The surviving animals were immediately treated with clindamycin for 16 weeks; they acquired a natural infection and seroconverted by the end of this time without clinical signs.
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87
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Measures LN, Dubey JP, Labelle P, Martineau D. Seroprevalence of Toxoplasma gondii in Canadian pinnipeds. J Wildl Dis 2005; 40:294-300. [PMID: 15362830 DOI: 10.7589/0090-3558-40.2.294] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sera (n = 328) collected from phocids (1995-97) from the east coast of Canada, including harp seals (Phoca groenlandica), hooded seals (Cystophora cristata), grey seals (Halichoerus grypus), and harbor seals (Phoca vitulina), were diluted 1:25, 1:50, and 1:500 and tested by a modified agglutination test for antibodies to Toxoplasma gondii. Titers equal to or greater than 1:25 were considered evidence of exposure. Grey seal (11/122, 9%), harbor seal (3/34, 9%), and hooded seal (1/60, 2%) had titers of 1:25 and 1:50. Harp seals (n = 112) were seronegative. Probable maternal antibody transfer was observed in one harbor and one grey seal pup at 10 and 14 day of age, respectively. Transmission of T gondii in the marine environment is not understood. The discovery of T. gondii in marine mammals might indicate natural infections unknown because of lack of study or might indicate recent contamination of the marine environment from the terrestrial environment by natural or anthropogenic activities.
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88
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Rah H, Chomel BB, Follmann EH, Kasten RW, Hew CH, Farver TB, Garner GW, Amstrup SC. Serosurvey of selected zoonotic agents in polar bears (
Ursus maritimus
). Vet Rec 2005; 156:7-13. [PMID: 15658561 DOI: 10.1136/vr.156.1.7] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Between 1982 and 1999 blood samples were collected from 500 polar bears (Ursus maritimus) captured in the Beaufort and Chukchi seas, to determine the seroprevalence of Brucella species, Toxoplasma gondii, and Trichinella species infections. The bears were classified into four age groups, cubs, yearlings, subadults and adults. Brucella and Toxoplasma antibodies were detected by agglutination (a buffered acidified card antigen and rapid automated presumptive test for brucellosis and a commercial latex agglutination test for toxoplasmosis); an ELISA was used to detect Trichinella antibodies. The overall seroprevalence of Brucella species was 5 per cent, and subadults and yearlings were 2-62 times (95 per cent confidence interval 1.02 to 6.82) more likely to be seropositive for Brucella species than adults and their cubs. The antibody prevalence for Toxoplasma gondii was 6 per cent, and for Trichinella species 55.6 per cent. The prevalence of antibodies to Trichinella species increased with age (P<0.001).
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89
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Hill DE, Sreekumar C, Gamble HR, Dubey JP. Effect of commonly used enhancement solutions on the viability of Toxoplasma gondii tissue cysts in pork loin. J Food Prot 2004; 67:2230-3. [PMID: 15508634 DOI: 10.4315/0362-028x-67.10.2230] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Retail meat cuts of pork are frequently enhanced with salt solutions to improve flavor and texture and to extend shelf life through reductions in microbial contamination. A study of the effect of commonly used meat enhancement solutions on the viability of Toxoplasma gondii tissue cysts was performed using tissues from experimentally infected mice and pigs. Brains of T. gondii-infected mice were injected to 110% of the original weight of the brain with solutions containing sodium chloride (1 and 2%), sodium diacetate (0.1 and 0.2%), sodium tripolyphosphate (0.25 and 0.5%), potassium lactate (1.4 and 1.96%), or sodium lactate (1.4, 1.5, and 2.0%) alone or in combination and stored at 4 degrees C for 7 days before feeding to T. gondii-seronegative cats. Loins were collected from pigs experimentally infected with T. gondii and injected as above and stored for 7, 28, or 45 days at 4 degrees C before feeding to T. gondii-seronegative cats. Cat feces were examined for 14 days to assess oocyst shedding. The present study demonstrated that injection of mouse brains or pork loins with solutions containing 2% sodium chloride or > or =1.4% potassium or sodium lactate, alone or in combination with other components, prevented transmission of T. gondii to cats.
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90
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Meireles LR, Galisteo AJ, Pompeu E, Andrade HF. Toxoplasma gondii spreading in an urban area evaluated by seroprevalence in free-living cats and dogs. Trop Med Int Health 2004; 9:876-81. [PMID: 15303992 DOI: 10.1111/j.1365-3156.2004.01280.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Infection by the protozoan parasite, Toxoplasma gondii is widely prevalent in humans and animals throughout the world. Transmission takes place mainly by ingestion of raw or undercooked meat that contains parasite cysts or by ingestion of oocysts excreted in cat faeces, which can contaminate water and raw vegetables. The incidence of toxoplasmosis in urban areas can thus be also related to environmental contamination with oocysts. A direct measure of this environmental contamination by oocyst counting is unfeasible for technical reasons. An interesting alternative for measuring T. gondii urban spreading is the seroprevalence in free-living urban animals, used as sentinels, once they are exposed to similar risks of Toxoplasma infection-like humans. With this aim, we tested serum samples from stray cats and dogs for antibodies to T. gondii by indirect haemagglutination assay (IHA) and enzyme-linked immunosorbent assay (ELISA). Antibodies to T. gondii were found in 40% (40 of 100) of the cats, less than the 50.5% (101 of 200) found in dogs by ELISA (P < 0.05). Haemagglutination showed low resolution and concordance, precluding their use for diagnosis of T. gondii infection compared with ELISA. The prevalence of T. gondii was lower among stray cats probably due to their selective alimentary habits and lower water and food intake. Toxoplasma gondii seroprevalence in stray dogs and cats could be an indirect indicator of the parasite spreading in urban areas.
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91
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Ekanayake DK, Rajapakse RPVJ, Dubey JP, Dittus WPJ. Seroprevalence of Toxoplasma gondii in Wild Toque Macaques (Macaca sinica) at Polonnaruwa, Sri Lanka. J Parasitol 2004; 90:870-1. [PMID: 15357087 DOI: 10.1645/ge-291r] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
From a natural population that inhabits the dry evergreen forest at Polonnaruwa, serum samples of 170 toque macaques were examined for antibodies to Toxoplasma gondii by the modified agglutination test. Of these, 21 (12%) were found with titers of 1:16 in 9, 1:32 in 9, 1:256 in 1, 1:1,024 in 1, and 1:4,096 in 1. There was no evidence of maternal transmission of antibodies or congenital toxoplasmosis. None of the infected macaques died within 1 yr after sampling. Toxoplasma gondii infection was closely linked to human environments where domestic cats were common. Macaques having frequent contact with human settlements showed a significantly greater (P < 0.0001) prevalence (19% infected) than macaques restricted to forest habitat, none of which was infected. Although infection with T. gondii has been noted in several species of Asian primates, this is the first report of T. gondii antibodies in toque macaques (Macaca sinica) that are endemic to the island of Sri Lanka.
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92
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Lhafi KS, Mitzscherling TA, Kühne M. [Parasites in meat: a challenge for veterinarians in meat hygiene]. DTW. DEUTSCHE TIERARZTLICHE WOCHENSCHRIFT 2004; 111:277-81. [PMID: 15366287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Meat hygiene is an important instrument of preventive public health since the end of the nineteenth century. The methods used during ante-mortem and post-mortem inspection are partly quite traditional. This is in particular true for the identification of parasites in meat. The aim of this review was to present facts on aetiology, prevalence and importance of meat-borne parasitic hazards. The capacity and the limits of the ante-mortem and post-mortem inspection for the identification of parasitic hazards are considered. Further, suggestions for the improvement of the meat hygiene are given. Cysticercosis, Toxoplasmosis and Sarcocystosis are exposed in detail. With regard to Cysticercosis, the integration of serological methods in the inspection procedure could result in a tenfold improvement of diagnostical sensitivity. With regard to Toxoplasmosis, it is obvious that meat containing Toxoplasma-cysts may reach the consumer, as animals infected with Toxoplasma gondii can neither be recognised in the ante-mortem inspection nor in the meat inspection. Systematical serological investigations on farm level would allow an appropriate judgement during meat inspection and minimize the consumer exposure to this parasite. Further, reliable methods for the detection of Toxoplasma-cysts have to be developed. With regard to Sarcocystosis, the compulsory inspection of the muscle surfaces to recognise a "massive infection with Sarcocystis" is very doubtful in its interpretation. There is a need for suitable microscopic, serological and molecular biological methods for the detection of Sarcocystis-species and reliable informations on the seroprevalence of the parasite in slaughtering animals.
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93
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The Cat Group policy statement 6. Cats and toxoplasmosis: what are the risks? J Feline Med Surg 2004; 6:iii-vi. [PMID: 15171223 PMCID: PMC10822440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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94
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Abou-Bacar A, Pfaff AW, Georges S, Letscher-Bru V, Filisetti D, Villard O, Antoni E, Klein JP, Candolfi E. Role of NK cells and gamma interferon in transplacental passage of Toxoplasma gondii in a mouse model of primary infection. Infect Immun 2004; 72:1397-401. [PMID: 14977944 PMCID: PMC356035 DOI: 10.1128/iai.72.3.1397-1401.2004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protective immunity in mice infected with Toxoplasma gondii is mainly mediated by NK cells, CD4 and CD8 T cells, and type 1 cytokines, such as gamma interferon (IFN-gamma). To clarify the roles of NK cells and IFN-gamma in protection against primary congenital toxoplasmosis, we used recombination activating gene 2 knockout (RAG-2(-/-)) mice, which lack T and B lymphocytes, in comparison with the wild-type BALB/c model. RAG-2(-/-) mice had a significantly lower risk of fetal toxoplasmosis than BALB/c mice (25 versus 63.9%; P = 0.003). This protection was associated with an increased number of maternal NK cells, IFN-gamma secretion by spleen cells, and decreased parasitemia. In the RAG-2(-/-) mice, NK cell depletion increased both the rate of fetal infection, to 56.5% (P = 0.02), and the blood parasite burden. Conversely, in the BALB/c mice, this treatment did not modify maternofetal transmission or the blood parasite burden. Neutralization of IFN-gamma in both infected RAG-2(-/-) and BALB/c mice decreased congenital Toxoplasma transmission, contrasting with an exacerbation of maternal infection. These data suggest that a partially protective immunity against congenital toxoplasmosis is achieved due to the increased number of NK cells in RAG-2(-/-) mice. However, it seems that IFN-gamma enhances, directly or indirectly, the transplacental transmission.
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MESH Headings
- Animals
- Cell Count
- DNA-Binding Proteins/deficiency
- DNA-Binding Proteins/genetics
- Female
- Infectious Disease Transmission, Vertical
- Interferon-gamma/biosynthesis
- Killer Cells, Natural/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Neutralization Tests
- Pregnancy
- Pregnancy Complications, Parasitic/immunology
- Toxoplasmosis, Animal/complications
- Toxoplasmosis, Animal/immunology
- Toxoplasmosis, Animal/transmission
- Toxoplasmosis, Congenital/etiology
- Toxoplasmosis, Congenital/immunology
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95
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Dubey JP, Ross AD, Fritz D. Clinical Toxoplasma gondii, Hammondia heydorni, and Sarcocystis spp. infections in dogs. PARASSITOLOGIA 2003; 45:141-6. [PMID: 15267102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Concurrent infections with coccidians Toxoplasma gondii, Sarcocystis spp., and a Hammondia heydorni-like parasite were identified in tissues of three littermate pups on a Kelpie dog breeding farm in Australia. In total, 20 pups in four litters had died following vaccination with an attenuated distemper virus vaccine. Toxoplasma gondii tachyzoites were identified immunohistochemically in tissues of two dogs. Sarcocystis sp. sporocysts were seen in the intestinal lamina propria of two dogs. Asexual and sexual stages of H. heydorni-like parasite were found in enterocytes of the small intestine of two dogs. Ultrastructural development of schizonts and gamonts of this parasite is described. None of the protozoa in these dogs reacted with antibodies to Neospora caninum. Feeding of uncooked tissue of sheep was considered to be the likely source of infection for these coccidians in dogs.
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96
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Sukthana Y, Kaewkungwal J, Jantanavivat C, Lekkla A, Chiabchalard R, Aumarm W. Toxoplasma gondii antibody in Thai cats and their owners. THE SOUTHEAST ASIAN JOURNAL OF TROPICAL MEDICINE AND PUBLIC HEALTH 2003; 34:733-8. [PMID: 15115080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Humans are thought to acquire Toxoplasma infection by three major routes: ingesting food and water contaminated with oocysts from cat excreta, consumption of under-cooked infected meat, and transplacental transfer. Congenital clinical toxoplasmosis in the newborn indicating definite transplacental transmission had been reported in Thailand, whilst studies concerning infection due to the other two routes were inconclusive. Since the way domestic cats live and eat and also the eating behavior of Thai people differ from those in the West, we conducted a sero-epidemiological study of T. gondii in cats and their owners in Bangkok metropolitan area. Among 327 humans, the prevalence of Toxoplasma antibody was 6.4% and in 315 cats it was 7.3%. These relatively low prevalence rates may result from the predominantly well-cooked fish and rice diet of stray cats, which congregate in temples where they are fed. Toxoplasma antibody seropositive was associated with living in close proximity to seropositivity cats [OR (95% CI) = 5.43 (1.28-23.04); p=0.01]. Risks were increased in and around temples, particularly if courtyards were of earth or grass, suggesting ground temperature was an important determinant of oocyst survival.
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97
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Arkush KD, Miller MA, Leutenegger CM, Gardner IA, Packham AE, Heckeroth AR, Tenter AM, Barr BC, Conrad PA. Molecular and bioassay-based detection of Toxoplasma gondii oocyst uptake by mussels (Mytilus galloprovincialis). Int J Parasitol 2003; 33:1087-97. [PMID: 13129531 DOI: 10.1016/s0020-7519(03)00181-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Toxoplasma gondii is associated with morbidity and mortality in a variety of marine mammals, including fatal meningoencephalitis in the southern sea otter (Enhydra lutris nereis). The source(s) of T. gondii infection and routes of transmission in the marine environment are unknown. We hypothesise that filter-feeding marine bivalve shellfish serve as paratenic hosts by assimilation and concentration of infective T. gondii oocysts and their subsequent predation by southern sea otters is a source of infection for these animals. We developed a TaqMan PCR assay for detection of T. gondii ssrRNA and evaluated its usefulness for the detection of T. gondii in experimentally exposed mussels (Mytilus galloprovincialis) under laboratory conditions. Toxoplasma gondii-specific ssrRNA was detected in mussels as long as 21 days post-exposure to T. gondii oocysts. Parasite ssrRNA was most often detected in digestive gland homogenate (31 of 35, i.e. 89%) compared with haemolymph or gill homogenates. Parasite infectivity was confirmed using a mouse bioassay. Infections were detected in mice inoculated with any one of the mussel sample preparations (haemolymph, gill, or digestive gland), but only digestive gland samples remained bioassay-positive for at least 3 days post-exposure. For each time point, the total proportion of mice inoculated with each of the different tissues from T. gondii-exposed mussels was similar to the proportion of exposed mussels from the same treatment groups that were positive via TaqMan PCR. The TaqMan PCR assay described here is now being tested in field sampling of free-living invertebrate prey species from high-risk coastal locations where T. gondii infections are prevalent in southern sea otters.
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98
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Cañon-Franco WA, Yai LEO, Joppert AM, Souza CE, D'Auria SRN, Dubey JP, Gennari SM. Seroprevalence of Toxoplasma gondii Antibodies in the Rodent Capybara (Hidrochoeris hidrochoeris) From Brazil. J Parasitol 2003; 89:850. [PMID: 14533702 DOI: 10.1645/ge-80r] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Capybaras (Hidrochoeris hidrochoeris) are 1 of the largest rodents used for meat in South and Central America. Prevalence of anti-Toxoplasma gondii antibodies in 149 feral H. hidrochoeris from the state of São Paulo, Brazil, was evaluated using the indirect immunofluorescent antibody test (IFAT) and the modified agglutination test (MAT). Using IFAT, antibodies (>1:16) were found in 104 (69.8%) and with the MAT, antibodies (>1:25) were found in 63 (42.3%) capybaras. This is the first report of prevalence of T. gondii antibodies in this host.
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99
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Lehmann T, Graham DH, Dahl E, Sreekumar C, Launer F, Corn JL, Gamble HR, Dubey JP. Transmission dynamics of Toxoplasma gondii on a pig farm. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2003; 3:135-41. [PMID: 12809808 DOI: 10.1016/s1567-1348(03)00067-4] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Transmission of Toxoplasma gondii infection on a pig farm in New England was investigated using genetic and ecological methods to (i) determine if infection of pigs was a result of a single source, such as in an epizootic situation (e.g. outbreak) or of multiple sources, such as in an enzootic situation, (ii) identify the main source species of infection to pigs and (iii) evaluate the role of the environment surrounding the farm as the source of infection on the farm. Genetic characterization of 25 T. gondii isolates from market pigs revealed three distinct genotypes with no evidence of recombinants. These data imply that at least three distinct exposure events occurred during the 7-month lifespan of these pigs. This genotype diversity is consistent with enzootic transmission of T. gondii on the farm. Cats were suspected as the main source of pig infection based on the high seroprevalence (>95%) in pigs. The presence of the two most common T. gondii genotypes in eight isolates from free ranging chickens on this farm corroborated the role of cats because chickens were probably infected through ingestion of oocysts in the soil. The seroprevalence of toxoplasmosis in 163 wild mammals and birds captured around the pig sties (overall 13.1%) increased with proximity to the pig sties. Thus, transmission of T. gondii was higher near the pig sties than in the surrounding environment probably because of increased density of oocysts there. We propose that the farm does not simply reflect its surroundings in terms of strain composition and risk of infection, but that it acts as a reservoir of strains from which the outflow of new infections into its surrounding environment is higher than the inflow.
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100
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Couper KN, Nielsen HV, Petersen E, Roberts F, Roberts CW, Alexander J. DNA vaccination with the immunodominant tachyzoite surface antigen (SAG-1) protects against adult acquired Toxoplasma gondii infection but does not prevent maternofoetal transmission. Vaccine 2003; 21:2813-20. [PMID: 12798622 DOI: 10.1016/s0264-410x(03)00163-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We examined the ability of a DNA vaccine comprising the Toxoplasma gondii tachyzoite immunodominant surface antigen, SAG-1, to both protect adult BALB/c mice against infection with the avirulent Beverly type-2 strain of T. gondii and also to inhibit the incidence of congenital disease. Vaccination induced an enhanced type-1 immune response as measured by IgG2a antibody production and increased splenocyte IFN-gamma production. Vaccination also limited disease following infection via either the oral or peritoneal routes as measured by mortality, pathology or brain cyst burden. While vaccination with plasmid alone also increased splenocyte IFN-gamma production, this afforded no protection and following infection mortality rates and cyst burden counts were similar in this group to that of non-vaccinated animals. Although, vaccination with SAG-1 DNA did protect against adult acquired T. gondii infection, it did not prevent maternofoetal transmission in previously vaccinated dams infected during pregnancy. The results indicate differences in the protective mechanisms operating between adult acquired disease and congenital transmission and have significant implications for future vaccine development.
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MESH Headings
- Animals
- Animals, Newborn
- Antigens, Protozoan/immunology
- Antigens, Surface/immunology
- Female
- Infectious Disease Transmission, Vertical
- Injections, Intraperitoneal
- Maternal-Fetal Exchange
- Mice
- Mice, Inbred BALB C
- Pregnancy
- Protozoan Proteins/immunology
- Time Factors
- Toxoplasmosis, Animal/congenital
- Toxoplasmosis, Animal/prevention & control
- Toxoplasmosis, Animal/transmission
- Vaccination
- Vaccines, DNA/immunology
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