Incidence of Toxoplasma gondii oocysts in cat feces

Within two years and a half, the faeces of 620 cats coming from Brno and the area around the city were subjected to parasitological examination with special regard to the occurrence of the oocysts of Toxoplasma gondii. Sucrose solution at the specific weight of 1,150 was used as flotation medium. Oocysts of Toxoplasma gondii were eliminated by eight cats (1.29%) at the age from 16 days to 1.5 years. Six of the eight cats were younger than seven months. The Toxoplasma gondii oocysts were eliminated by the cats for 1-16 days while exhibiting signs of short-term scours and swelling of lymph nodes. In all cases the oocysts of Toxoplasma gondii were produced in the summer and autumn seasons (June-December). During the patent period, other coccidia (Isospora felis and Isospora rivolta) were also present in the cats.     

Prevalence and genotypes of Toxoplasma gondii in feline faeces (oocysts) and meat from sheep, cattle and pigs in Switzerland

The protozoan parasite Toxoplasma gondii infects almost all warm blooded animal species including humans, and is one of the most prevalent zoonotic parasites worldwide. Post-natal infection in humans is acquired through oral uptake of sporulated T. gondii oocysts or by ingestion of parasite tissue cysts upon consumption of raw or undercooked meat. This study was undertaken to determine the prevalence of oocyst-shedding by cats and to assess the level of infection with T. gondii in meat-producing animals in Switzerland via detection of genomic DNA (gDNA) in muscle samples. In total, 252 cats (44 stray cats, 171 pet cats, 37 cats with gastrointestinal disorders) were analysed coproscopically, and subsequently species-specific identification of T. gondii oocysts was achieved by Polymerase Chain Reaction (PCR). Furthermore, diaphragm samples of 270 domestic pigs (120 adults, 50 finishing, and 100 free-range animals), 150 wild boar, 250 sheep (150 adults and 100 lambs) and 406 cattle (47 calves, 129 heifers, 100 bulls, and 130 adult cows) were investigated by T. gondii-specific real-time PCR. For the first time in Switzerland, PCR-positive samples were subsequently genotyped using nine PCR-restriction fragment length polymorphism (PCR-RFLP) loci (SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) for analysis. Only one of the cats shed T. gondii oocysts, corresponding to a T. gondii prevalence of 0.4% (95% CI: 0.0-2.2%). In meat-producing animals, gDNA prevalence was lowest in wild boar (0.7%; 95% CI: 0.0-3.7%), followed by sheep (2.0%; 95% CI: 0.1-4.6%) and pigs (2.2%; 95% CI: 0.8-4.8%). The highest prevalence was found in cattle (4.7%; 95% CI: 2.8-7.2%), mainly due to the high prevalence of 29.8% in young calves. With regard to housing conditions, conventional fattening pigs and free-range pigs surprisingly exhibited the same prevalence (2.0%; 95% CI: 0.2-7.0%). Genotyping of oocysts shed by the cat showed T. gondii with clonal Type II alleles and the Apico I allele. T. gondii with clonal Type II alleles were also predominantly observed in sheep, while T. gondii with mixed or atypical allele combinations were very rare in sheep. In pigs and cattle however, genotyping of T. gondii was often incomplete. These findings suggested that cattle in Switzerland might be infected with Toxoplasma of the clonal Types I or III, atypical T. gondii or more than one clonal Type.     

Sarcocystis capracanis and Toxoplasma gondii infections in range goats from Texas

Specimens of tongues, esophagi, diaphragms, or abdominal muscles of 115 range goats from San Angelo, Tex, were examined for Sarcocystis and Toxoplasma gondii infections. Sarcocystis spp zoites were found microscopically in pepsin digests of muscles of 60.8% goats and sarcocysts of S capracanis were found in histologic sections of 27.8% goats. Sarcocysts were more common in sections of tongue (19.1%) than in those of other muscles (9.9% to 10.7%). A dog fed Sarcocystis-infected tissues shed sporocysts in feces, whereas 2 cats fed the same tissues did not shed sporocysts. Toxoplasma gondii was neither seen in histologic sections of goat tissues nor found by bioassays in mice or cats. Mice inoculated with pepsin digests of muscles did not develop T gondii infection and 2 cats fed goat tissues did not shed oocysts. Also, antibody to T gondii was not found in serum samples from goats. The low prevalence of T gondii infection in range goats may be because of the relative absence of domestic cats on Texas ranges.     

Detection of Toxoplasma gondii-like oocysts in cat feces and estimates of the environmental oocyst burden

OBJECTIVE: To estimate the analytic sensitivity of microscopic detection of Toxoplasma gondii oocysts and the environmental loading of T gondii oocysts on the basis of prevalence of shedding by owned and unowned cats. DESIGN: Cross-sectional survey. SAMPLE POPULATION: 326 fecal samples from cats. PROCEDURES: Fecal samples were collected from cat shelters, veterinary clinics, cat-owning households, and outdoor locations and tested via ZnSO(4) fecal flotation. RESULTS: Only 3 (0.9%) samples of feces from 326 cats in the Morro Bay area of California contained T gondii-like oocysts. On the basis of the estimated tonnage of cat feces deposited outdoors in this area, the annual burden in the environment was estimated to be 94 to 4,671 oocysts/m(2) (9 to 434 oocysts/ft(2)). CONCLUSIONS AND CLINICAL RELEVANCE: Despite the low prevalence and short duration of T gondii oocyst shedding by cats detected in the present and former surveys, the sheer numbers of oocysts shed by cats during initial infection could lead to substantial environmental contamination. Veterinarians may wish to make cat owners aware of the potential threats to human and wildlife health posed by cats permitted to defecate outdoors.     

The development of a molecular approach for coprodiagnosis of Toxoplasma gondii

Copro-diagnostic methods for Toxoplasma gondii infected cats have been traditionally based on the identification of oocysts by light microscopy or by bioassays. The first method is not sensitive and also unable to differentiate between Toxoplasma oocysts from other coccidian parasites in cats, and the second is cumbersome, time consuming and expensive. We have adapted a polymerase chain reaction (PCR) method to detect T. gondii oocyst DNA in fecal samples. Oocysts were successfully disrupted by freeze thawing coupled with mechanical means, and DNA extraction was subsequently accomplished. The test, based on amplifying a 529 bp repeated sequence, proved sensitive for detecting 1-2 oocysts in 200 microg of stool sample. The test specificity was established by showing that DNA from other cat coccidia tested negative. Specificity was reconfirmed by Southern hybridization of the PCR products with a specific probe. Of 122 stool samples from Jerusalem cats surveyed for the presence of Toxoplasma oocysts, 11 were found positive by PCR while none was detected by microscopy.     

Long-term persistence of Toxoplasma gondii in tissues of pigs inoculated with T gondii oocysts and effect of freezing on viability of tissue cysts in pork

To study the distribution of tissue cysts in porcine tissues, 16 pigs were fed oocysts of 4 strains of Toxoplasma gondii (4 pigs/strain). Pigs were euthanatized between postinoculation days 103 and 875 and portions of 5 to 14 organs were bioassayed in mice and/or cats for T gondii. For bioassays, 50- to 100-g portions of tissue were incubated in acidic pepsin solution to free bradyzoites from cysts in parenchyma, and washed sediment from the digests of each specimen was inoculated SC into mice (6 mice/organ). For bioassays in cats, a 500-g portion or whole organ was fed to Toxoplasma-free cats (1 cat/organ). Toxoplasma gondii was recovered from tissues of 14 of the 16 pigs (from the brains of 12, hearts of 11, tongues of 10, and diaphragms of 6). Toxoplasma gondii was isolated from commercial cuts of meat from 5 infected pigs; from the arm picnic and ham of 3, Boston butt, spareribs, and tenderloin of 2, and bacon and tailbone of 1. Regarding the 4 pigs euthanatized between postinoculation days 759 and 865, cats shed T gondii oocysts after the ingestion of hearts of all 4; tongues of 3; bacons, hams, arm picnics, Boston butts, spareribs, and diaphragms of 2; and livers, kidneys, and tenderloins of 1. Toxoplasma gondii was found to be inconsistently distributed among the organs and muscles, but overall, tongue and heart were more heavily infected than were other tissues. Tissue cysts in pork were rendered nonviable at -12 C for 3 days.     

Comparative infectivity of oocysts and bradyzoites of Toxoplasma gondii for intermediate (mice) and definitive (cats) hosts

Tachyzoites, bradyzoites (in tissue cysts), and sporozoites (in oocysts) are the three infectious stages of Toxoplasma gondii. The prepatent period (time to shedding of oocysts after primary infection) varies with the stage of T. gondii ingested by the cat. The prepatent period (pp) after ingesting bradyzoites is short (3-10 days) while it is long (18 days or longer) after ingesting oocysts or tachyzoites. The conversion of bradyzoites to tachyzoites and tachyzoites to bradyzoites is biologically important in the life cycle of T. gondii and it has been proposed that the pp can be used to study stage conversion. In the present study, infectivity of oocysts and bradyzoites released from tissue cysts of a recent isolate of T. gondii, TgCkAr23, to cats and mice was compared. Ten-fold dilutions of oocysts or bradyzoites were administered orally to cats, and orally and subcutaneously to mice. Of the 29 cats each fed 1-10 million oocysts only one cat shed oocysts and the pp was 23 days; all cats remained asymptomatic. In contrast, all mice administered the same 10-fold dilutions of oocysts either orally or subcutaneously died of toxoplasmosis. The results confirm that infectivity of the oocysts to cats is lower than for mice and that oocysts are non-pathogenic for cats. Of the 41 cats each fed 1-1,000 free bradyzoites, 15 shed oocysts with a short pp of 4-9 days, and all remained asymptomatic. The infectivity of bradyzoites to mice by the oral route was approximately 100 times lower than that by the subcutaneous route. The results confirm the hypothesis that the pp in cats is stage and not dose dependent, and that transmission of T. gondii is most efficient when cats consume tissue cysts (carnivory) or when intermediate hosts consume oocysts (fecal-oral transmission).     

Genetic and biologic characteristics of Toxoplasma gondii infections in free-range chickens from Austria

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in free-range chickens (Gallus domesticus) from 11 Bio-farms in Austria was determined. Antibodies to T. gondii assayed by the modified agglutination test (MAT) were found in 302 of 830 (36.3%) chickens with titers of 1:10 in 50, 1:20 in 69, 1:40 in 53, 1:80 in 40, 1:160 or higher in 90. Hearts of 218 chickens with MAT titers of 10 or higher were bioassayed individually in mice. Tissues from 1183 chickens were pooled and fed to 15, T. gondii-free cats. Feces of the cats were examined for oocysts; 11 cats shed T. gondii oocysts. T. gondii was isolated from 56 chickens by bioassay in mice. Thus, there were 67 isolates of T. gondii from these chickens. Genotyping of these 67 isolates using the SAG2 locus indicated that all 33 were Type II. Phenotypically and genetically these isolates were different from T. gondii isolates from Brazil. None of the isolates was virulent for mice. This is the first report of isolation of T. gondii from chickens from Austria.     

A survey for Toxoplasma gondii antibodies in deer and other wildlife on a sheep range.

Blood samples were obtained from native mammals and birds on a sheep range (Hopland Field Station) in northern California. Serums were tested for antibodies to Toxoplasma gondii by the indirect hemagglutination test. Of 382 deer that were tested from 1964 to 1973, 77 (20%) were seropositive for T gondii. Among 36 serums representing 6 species of wild carnivores (badgers, bobcats, coyotes, foxes, raccoons, and skunks), 18 (50%) were seropositive. All of the 5 bobcats tested were seropositive, with antibody titers ranging from 1:65,536. The testing of 175 serums from small wild mammals indicated antibody prevalence of 8% among jackrabbits, 6% among brush rabbits, and 2% among squirrels. None of the native mice tested was seropositive for T gondii. Of 120 native birds tested, 6 (5%) were seropositive. Of the resident domestic species of animals tested, antibodies were found in 1 of 7 domestic cats, 1 of 5 feral cats, 1 of 2 dogs, and 54 (13%) of 405 sheep.     

成都市区犬猫狂犬病病毒和弓形虫感染的调查

为了解四川省成都市区家养犬、猫狂犬病病毒及弓形虫的感染情况,采用商品化狂犬病病毒和弓形虫抗原快速检测试纸卡,对2010年8～10月间来自成都市区的103份家养犬以及75份家猫的唾液和血液样品进行检测;同时采用文献报道的PCR方法对家养犬血液样品中的弓形虫核酸进行检测。结果显示,103份家养犬唾液样品狂犬病病毒抗原均为阴性,而75份家猫唾液样品中,检出阳性样品5份(阳性率6.7%),可疑样品7份;103份家养犬血液样品弓形虫抗原阳性样品33份(32.0%),可疑样品22份,75份家猫血液样品中,检出阳性样品2份(阳性率2.7%),可疑样品3份。弓形虫核酸PCR检测结果显示,96份家养犬血液样品弓形虫核酸阳性样品57份(阳性率59.4%),与弓形虫抗原阳性和可疑样品总和所占比例基本一致(53.4%)。提示应重视源于家猫的狂犬病病毒和家养犬弓形虫对人的威胁。     

Acute primary toxoplasmic hepatitis in an adult cat shedding Toxoplasma gondii oocysts

A 3-year-old 4-kg neutered male domestic shorthair cat died within 5 days after onset of fever and respiratory distress. At necropsy, all tissues were icteric, and the liver had a diffuse reticular pattern. Histologically, hepatitis and encephalitis were associated with Toxoplasma gondii tachyzoites. Toxoplasma gondii female gamonts and oocysts were found in epithelial cells of intact villi and in epithelial cells desquamated into the lumen. Finding of acute hepatitis and T gondii oocysts in an adult cat without detectable immunodeficiency is unusual, because adult cats rarely have clinical signs of toxoplasmosis during the oocyst-shedding phase.     

Toxoplasma gondii infection in cats from São Paulo state, Brazil: seroprevalence, oocyst shedding, isolation in mice, and biologic and molecular characterization

Cats are the most important hosts in the epidemiology of Toxoplasma gondii infections in humans and animals. Serologic and parasitological prevalence of T. gondii were determined in 237 cats from 15 counties in S?o Paulo state, Brazil. Antibodies to T. gondii were found in a 1:25 dilution of serum of 84 (35.4%) out of 237 cats by the modified agglutination test (MAT). Samples of brain, heart, tongue, and limb muscles (total 50 g) of 71 of the seropositive cats were pooled for each cat, digested in pepsin and bioassayed in mice. Faeces (1 g) from the rectum of each cat were examined microscopically for T. gondii-like oocysts and verified by bioassay in mice; T. gondii oocysts were found in the faeces of three (1.3%) of 237 cats. T. gondii was isolated from tissue homogenates of 47 cats. The DNA obtained from these 47 tissue isolates was characterized using the SAG2 locus: 34 (72.4%) isolates were type I, 12 (25.5%) were type III and one (2.1%) was mixed with types I and III. No type II isolates were detected. Most (23/34) of the type I isolates killed all infected mice and 7 of 12 type III isolates did not kill infected mice. Characterization of the SAG2 locus directly from tissue homogenates from 37 of 46 cats was successful. Genotypes obtained from these primary samples were the same as those from the corresponding isolates obtained in mice. Genotyping of the three oocyst isolates revealed that two were type I and one was type III. Molecular and biologic characteristics of T. gondii isolates from animals from Brazil are different from those from other parts of the world.     

Effect of irradiation on the viability of Toxoplasma gondii cysts in tissues of mice and pigs

Muscles from tongue, heart, and limbs of 14 pigs inoculated orally with Toxoplasma gondii oocysts were irradiated with 10, 20, 25, and 30 krad of gamma (cesium-137 and cobalt-60) irradiation. Viability of T gondii cysts was assayed by feeding porcine muscles to T gondii-free cats and/or by inoculation of sediment from acid-pepsin digested porcine muscle into mice. Cats fed 500-g samples of muscles irradiated with up to 20 krad shed T gondii oocysts. Cats fed muscles irradiated with 25 or 30 krad did not shed oocysts. Mice were inoculated with 8 isolates of T gondii, and tissue cysts in their brains irradiated with up to 40 krad were infective to mice; however, there was a 10,000-fold reduction in the viability of organisms in tissue cysts irradiated with 40 krad, compared with that in nonirradiated cysts. At 50 krad of gamma irradiation, there were no detectable infective organisms in infected mouse brains.     

Isolation and characterization of Toxoplasma gondii strains from stray cats revealed a single genotype in Beijing, China

Cats are essential in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete the environmentally resistant oocysts in nature. This study was aimed to determine the seropositivity, distribution of genotypes and mouse virulence of T. gondii from stray cats in Beijing, China. A total of 64 serum samples, 23 feces and tissue samples were collected from stray cats in Beijing. Antibodies to T. gondii were assayed by the modified agglutination test (MAT). 57.8% (37/64) of these stray cats had titers of 1:20 or higher and were considered positive with infection. T. gondii oocysts were not found in feces of the 23 cats. Tissues of 23 cats were bioassayed in mice and 11 T. gondii isolates were obtained. The genotype of these isolates were identified by 11 PCR-RFLP markers, including SAG1, (3'+5')SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast marker, Apico. Only one genotype was identified. This genotype, designated as ToxoDB genotype #9, was previously reported in cats, pigs and human from Guangdong and Gansu provinces in China and animals from a few other countries. To determine mouse virulence of this lineage of parasites, one isolate was randomly selected and inoculated into BABL/c mice, the result showed that it is intermediately virulent to mice. These results indicated that an atypical, intermediately virulent T. gondii lineage is widespread in China. The high seropositivity of T. gondii in stray cats posts potential risk of transmission of the parasite to human population in the region.     

Incidence of Neospora caninum and other intestinal protozoan parasites in populations of Swiss dogs

The protozoan parasite Neospora caninum is one of the most important abortifacient organisms in cattle worldwide. The dog is known to act as definitive host although its potential role as infection source for bovines still remains unelucidated. The aim of the present study was to compile initial epidemiological data on the prevalence and incidence of N. caninum in Swiss dogs acting as definitive hosts. Thus, 249 Swiss dogs were investigated coproscopically in monthly intervals over a period of 1 year. A total of 3289 fecal samples was tested by the flotation technique. Among these, 202 were shown to contain Sarcocystis sp. (6.1%), 149 Cystoisospora sp. (=Isospora sp.; 4.5%) and 25 Hammondia/Neospora-like oocysts (HNlO) (0.7%). All but one sample containing HNlO were from different dogs; one dog shed HNlO at two subsequent time points. Calculation of the yearly incidence for HNlO resulted in the surprisingly high value of 9.2%. Farm dogs exhibited a higher incidence for HNlO than urban family dogs. Thirteen out of the 25 HNlO-samples showed sporulation after 5 days incubation at room temperature. HNlO were further differentiated by species-specific PCR. However, all HNlO-samples were negative for N. caninum, Hammondia heydorni and Toxoplasma gondii. One reason may be the low oocyst density found in most fecal samples, which did not permit us to carry out PCR under optimal conditions. Three out of the 25 HNlO-cases contained enough oocysts to allow further enrichment and purification by the flotation technique. Subsequently, twenty to fifty sporulated HNlO-oocysts were orally administered to Meriones unguiculatus. All gerbils were seronegative for N. caninum at 5 weeks p.i. A N. caninum-seroprevalence of 7.8% was determined by ELISA upon 1132 serum samples collected from dogs randomly selected by veterinarians among their clinical patients.     

弓形虫不同发育时期棒状体颈部蛋白5基因的表达研究

为探究不同发育时期弓形虫棒状体颈部蛋白5（Toxoplasma gondii rhoptry neck protein 5,TgRON5）基因的表达情况与其毒力的相关性,本试验以Ⅱ型弓形虫PRU虫株作为研究对象,以弓形虫管家基因ACT1作为内参基因,分别对目的基因和内参基因设计特异性引物,通过对各基因建立标准曲线,确定二者扩增效率的一致性后,采用实时荧光定量PCR相对定量法对弓形虫4个不同发育时期（速殖子、缓殖子、未孢子化卵囊及孢子化卵囊）中TgRON5基因的表达情况进行检测与分析。结果显示,TgRON5基因在弓形虫各发育时期均有表达,其中,孢子化卵囊表达水平最高,未孢子化卵囊次之,速殖子较低,缓殖子最低,表明RON5蛋白的合成与分泌与虫体入侵宿主细胞的侵袭力有着密切的关系。本研究结果为阐明TgRON5蛋白参与弓形虫入侵的机理奠定了基础。     

Study on Expression of Toxoplasma gondii Rhoptry Neck Protein 5 Gene in Different Developmental Stages

To investigate the relationship between the expression level of Toxoplasma gondii rhoptry neck protein 5 (TgRON5) gene in different developmental stages and the virulence of Toxoplasma gondii, the objective of this study was to examine the different expression of TgRON5 gene in different developmental stages of type Ⅱ Toxoplasma gondii PRU strain. Specific primers were designed according to the sequence of TgRON5 gene, and ACT1 gene of Toxoplasma gondii was used as a reference gene. Following the establishment of standard curve for the target and reference genes, in order to confirm the consistency of their amplification efficiency, Real-time PCR method was applied to determine and compare the expression level of TgRON5 gene in development stage which including tachyzoite, bradyzoite, non-sporulated oocyst and sporulated oocyst. The results demonstrated that TgRON5 was expressed in all developmental stages but the sporulated oocysts had the highest expression, followed by the non-sporulated oocysts, the third was tachyzoite, and the lowest was bradyzoite. It suggests that the synthesis and secretion of TgRON5 protein was closely associated with the invasiveness of the parasite. All these findings had important implications for elucidating the functions of TgRON5 involved in the invasion of Toxoplasma gondii.     

Genetic and biologic characterization of Toxoplasma gondii isolates of cats from China

Cats are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete the environmentally resistant oocysts. In the present study, prevalence of T. gondii was determined in serum, feces, and tissues of 34 cats from People's Republic of China. Antibodies to T. gondii were assayed by the modified agglutination test and found in 27 of 34 (79.4%) cats with titers of 1:40 in one, 1:80 in one, 1:160 in three, 1:320 in three, 1:640 in eight, and 1:1280 or higher in 11 cats. T. gondii oocysts were not found in feces of any cat as ascertained by bioassay in mice. Tissues (brain, heart, and tongue) of 27 seropositive cats were pooled and bioassayed in mice (8 cats) or cats (19 cats). T. gondii was isolated from tissues of 17 of 27 seropositive cats. Genotyping of these 17 T. gondii isolates using polymorphisms at 10 nuclear markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and a new SAG2, and an apicoplast marker Apico revealed two genotypes. This is the first report of genetic typing of T. gondii isolates from cats from China.     

Survival of nonsporulated Toxoplasma gondii oocysts under refrigerator conditions.

Toxoplasma gondii oocysts are excreted nonsporulated in the feces of the cats into the environment. These oocysts must undergo sporulation to become infectious. Little is known about the factors that influence sporulation of T. gondii oocysts. The present study examined the survival of nonsporulated oocysts under refrigerated conditions over 11-week observation period. Microscopic examination of oocysts indicated that no visible development occurred under refrigerator conditions. The nonsporulated oocysts retained their ability to sporulate when placed at room temperature. The numbers of visually viable appearing oocysts decreased over time. Some oocysts in all samples were infectious for mice despite being refrigerated for up to an 11 weeks before undergoing sporulation. Results indicate that nonsporulated oocysts can survive in the environment for at least 3 months and retain their ability to become infectious when placed under appropriate conditions.     

In vitro isolation and seroprevalence of Toxoplasma gondii in stray cats and pigeons in Lisbon, Portugal

Oral contamination with Toxoplasma gondii oocysts shed by cats into the environment has been linked to severe outbreaks of human toxoplasmosis. Pigeons (Columba livia) are highly susceptible to oral infection with oocysts and indirectly indicate soil contamination, since they feed from the ground. A seroprevalence study was performed on cats and pigeons captured in the city of Lisbon. Serum samples collected from 1507 pigeons captured at 64 feeding sites and 423 stray cats were screened for antibodies anti-T. gondii using a commercial direct agglutination test. Seroprevalence in pigeons was 2.6% (39/1507) (95% CI: 1.9-3.5%) and 37.5% (24/64) of pigeon flocks sampled showed to be infected with T. gondii. The proportion of infected pigeons within seropositive flocks ranged between 4.8% and 21.1%. Among cats, seroprevalence was 44.2% (187/423) (95% CI: 39.5-49.1%). Isolation of T. gondii from animal tissues was attempted by in vitro assay. Inoculation of brain homogenates from 20 pigeons and 56 cats into Vero cell cultures allowed isolation of T. gondii from 13 pigeons (65%) and 15 cats (26.8%). Inoculation of muscle homogenates (heart and limbs) prepared by acid-peptic digestion from a subset of 15 cats resulted in the recovery of T. gondii from 10 cats (66.7%).