Toxoplasmosis in Pallas' cats (Otocolobus felis manul) at the Denver Zoological Gardens.

In May 1996 the Denver Zoological Gardens obtained two male and two female Pallas' cats (Otocolobus felis manul) that were wild-caught in the Ukraine. These animals were part of a group of 16 wild-caught adults (eight male and eight female) imported to the United States and Canada between 1995 and 1996. The Denver Zoological Gardens cats were quarantined at the zoo hospital for approximately I mo. During the quarantine period they were immobilized for physical examination, and sera were obtained from them to evaluate for exposure to Toxoplasma gondii. All cats were positive for T. gondii antibodies by latex agglutination (titers from 1:512 to 1:1,024). After being paired for breeding, one pair produced two litters, and another pair produced four litters, a total of 17 kittens between 1997 and 2001. Four kittens and two young adults died from a disseminated granulomatous and necrotizing inflammation consistent with toxoplasmosis. Toxoplasma gondii infection was confirmed in all six deceased cats by polymerase chain reaction performed on formalin-fixed tissues. An additional five kittens disappeared and were not available for necropsy. The fatality rate from toxoplasmosis was 35.3% (6/17) for cats that were available for necropsy and could have been as high as 64.7% (11/17) if it were assumed that the disappeared kittens were also affected. The Pallas' kitten survival rate at the Denver Zoological Gardens was 35.3%. This article describes the clinical and pathologic features of toxoplasmosis in a group of Pallas' cats at the Denver Zoological Gardens.     

Attempted transmission of Toxoplasma gondii infection from pregnant cats to their kittens

Sixteen 1- to 7-week-old pregnant specific-pathogen free cats were inoculated orally with Toxoplasma gondii cysts. Fetuses and neonatal kittens were examined for toxoplasma infection by inoculating suspensions of their tissues into mice. Toxoplasma gondii was not isolated from 23 fetuses and 16 newborn kittens from 13 queens. Six (3 litters) of the 15 kittens from the 3 remaining queens were killed on the day of or a day after birth, and the remaining 9 kittens were housed with their mothers for 7 to 33 days. None of the 9 kittens from the 2 litters examined between 0 and 33 days of age was infected with T gondii. In the other litter, T gondii was isolated from 3 kittens killed at 9, 16, and 22 days of age but not from 3 littermates killed on days 1, 1, and 22. Internal organs from the 3 kittens with proved toxoplasma infectivity in mice were examined histologically. Multifocal granulomatous encephalitis, hepatitis, nephritis, myocarditis, myositis, and interstitial pneumonia were found in all 3 kittens. Toxoplasma forms were demonstrated histologically in the tissues of 2 of these kittens. The mode of toxoplasma infection in newborn kittens was not determined but did not appear to be either transplacental or via fecal contamination from oocysts excreted by the mother cat. Evidence obtained in these experiments suggests that transplacental toxoplasma infection in the cat is not an important epidemiologic factor in perpetuation of the disease in the feline population.     

Prevention of shedding and re-shedding of Toxoplasma gondii oocysts in experimentally infected cats treated with oral Clindamycin: a preliminary study

This work aimed to evaluate the effects of preventive oral Clindamycin in cats infected with Toxoplasma gondii. Twelve short hair cats were divided into two groups (group 1 and group 2). No titres of T. gondii antibodies were detected in these cats before the experiment. The animals from group 1 were infected with tissue cysts of T. gondii and group 2 were infected and treated with Clindamycin (20 mg/kg/day). The infection was done with almost 40-50 tissue cysts for each cat on day 0. The cats from group 2 were treated with Clindamycin by oral rout for 24 days (from day -3 to day 21). At day 45, the groups 1 and 2 were divided into two subgroups with three animals each. Subgroups 1A and 2A were immunosuppressed with dexamethasone (1 mg/kg/day) for30 days and subgroups 1B and 2B were not immunosuppressed. Faecal exam looking for oocyst shedding was made by 30 days after T. gondii infection, and for 30 days after immunosuppression. All kittens from group 1 shedding oocysts after infection, while animals from group 2 did not shed. After immunosuppression period, all animals from group 1A re-shed oocysts and animals from group 2A remained without shed. However, 2 (66.6%) of the kittens from subgroup 2B shed oocysts 19-20 days after re-challenge. Based on this preliminary study, Clindamycin had a complete inhibitory effect on shedding of oocysts by cats, even under severe immunosuppression, which is a new finding not reported elsewhere.     

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.     

Detection of Toxoplasma gondii in the milk of experimentally infected lactating cats.

Tachyzoites of Toxoplasma gondii have been found in the milk of sheep, goats, cows and mice and infection by ingestion of raw goat milk has been documented in humans. Lactational transmission from infected cats to their kittens is suspected but the organism has not been detected in the milk. The purpose of this study was to demonstrate the presence of T. gondii in the milk of experimentally infected cats. Pregnant specific pathogen free cats were inoculated orally with T. gondii at various times prior to parturition. Feces were examined for oocyst shedding after sugar solution centrifugation. Milk was collected for polymerase chain reaction (PCR) and bioassay in mice. T. gondii was detected in the milk of five of six cats by either bioassay or PCR.     

Transmission of feline leukaemia virus in the milk of a non-viraemic cat

The possibility of the transmission of feline leukaemia virus (FeLV) from latently infected cats was studied. Five female cats with latent infections were examined for evidence of transmission of the virus to their kittens. One of the cats infected members of four consecutive litters of kittens which subsequently became persistently viraemic and transmitted the virus to other susceptible kittens by contact. Shortly after birth its kittens were apparently FeLV-free since neither viral antigen nor infectious virus was detected in their blood and no virus was found in cell cultures made from aspirates of bone marrow. The kittens became viraemic from 45 days of age onwards at a time when their passively acquired colostral FeLV neutralising antibodies were no longer detectable. Transmission of the virus occurred via the milk since both FeLV antigen and infectious virus were found in milk samples taken six weeks after kittening and the virus was transmitted to a fostered kitten. Eleven weeks after the birth of the fourth litter the cat became viraemic. The intermittent presence of FeLV antigens detected by the Leukassay F test, but not infectious virus, in the plasma of this cat over the previous months and a low level of serum neutralising antibodies distinguished it from four other latently infected queens which did not transmit infection to their kittens. These factors may indicate a risk of milk transmission and reactivation of latent virus.     

Immunoglobulin concentrations in feline colostrum and milk, and the requirement of colostrum for passive transfer of immunity to neonatal kittens

The purpose of this study was to clarify whether cats have a colostral and milk phase of lactation differentiated by concentrations of immunoglobulins, and whether colostrum ingestion by newborn kittens is essential for optimal transfer of passive immunity. Milk from specific pathogen-free queens was analyzed for IgG and IgA concentrations from parturition through 6 weeks of lactation. Serum IgG and IgA concentrations from birth through 8 weeks of age were determined for colostrum-fed kittens, colostrum-deprived kittens that were fed a milk replacer, and colostrum-deprived kittens that were fostered onto queens in the milk phase of lactation. The total IgG and IgA concentrations in milk were significantly higher on the day of parturition than on day 7 of lactation, indicating cats do have a colostral phase of lactation. The predominant immunoglobulin in both colostrum and milk was IgG. The serum IgG concentrations in colostrum-deprived kittens fostered on queens in the milk phase of lactation were similar to colostrum-deprived kittens fed a milk replacer, and the concentrations were significantly lower than in colostrum-fed kittens for the first 4 weeks of life. The serum IgA concentrations in both colostrum-deprived groups were significantly lower than colostrum-fed kittens on day 2 after parturition, but were similar thereafter. Colostrum-deprived kittens fostered onto queens in the milk phase of lactation had failure of passive transfer of maternal antibodies. Protective concentrations of immunoglobulins can be restored in kittens with failure of passive transfer of immunity by parenteral administration of adult cat serum, but not by fostering on queens in mid-lactation.     

Macrophage functions in cats experimentally infected with feline immunodeficiency virus and Toxoplasma gondii.

It was suspected that feline immunodeficiency virus (FIV) infection would affect the function of feline macrophages, and that the concomitant infection of cats with FIV and Toxoplasma gondii would cause even greater changes in macrophage function. Sixteen specific-pathogen-free kittens, four per group, were infected either with FIV, T. gondii, both pathogens, or neither pathogen. After the cats had been infected with FIV for 14 weeks (8 weeks after T. gondii infection), peritoneal macrophages were collected. Some macrophages were stimulated with lipopolysaccharide and supernatants were collected for the measurement of interleukin-1 production. Other macrophages were infected with T. gondii in a microbiocidal assay. Peritoneal macrophages from cats infected with FIV had decreased interleukin-1 secretion and increased antimicrobial activity. Co-infection with T. gondii apparently had no effect on these modifications of macrophage activity. Thus, acute FIV infection alone caused significant changes in macrophage functions that were not affected by concomitant T. gondii infection.     

Soil contamination of Toxoplasma gondii oocysts in pig farms in central China

Toxoplasmosis in pigs is a large threat to pig industry as well as pork consumers. Most pigs become infected by ingestion of oocysts from contaminated environment (soil, water and feed) or infected animal tissues postnatally. In the present study, field studies were conducted to evaluate the relationship between soil contamination status of Toxoplasma gondii oocysts and T. gondii infection in pigs in 12 pig farms with different density of cats in central China. The presence of T. gondii oocysts in soil were determined by PCR and loop-mediated isothermal amplification (LAMP). T. gondii DNA was found in 11 farms with different cat density excepting one farm exposed to low cat density. Twenty (21.1%) and 36 (37.9%) of 95 soil samples were T. gondii positive by PCR and LAMP, respectively (0.01相似文献   

Neonatal toxoplasmosis in kittens

The occurrence of toxoplasmosis is described in the cat-mother and three kittens. Clinical symptoms were not significant: bristled hair, conjunctivitis, sneezing and hypertrophy of mandibular and popliteal lymph nodes. The titres of antibodies to Toxoplasma gondii were demonstrated in all kittens and also in the cat: Sabin-Feldman reaction titre 4-32, complement-fixing reaction titre 5-40. Microprecipitation in agar gel was positive in all animals. Oocytes of Toxoplasma gondii were eliminated through faeces by the cat and two 16-day-old kittens. An isolation trial on white mice with a negative finding of toxoplasmosis (inoculation of brain, liver and spleen samples) has demonstrated toxoplasmosis in all animals under study. Most probably the kittens were infected transplacentally.     

Characterization of Toxoplasma gondii isolates from free range chickens from Paraná, Brazil

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 40 free range chickens (Gallus domesticus) from a rural area surrounding Paraná, Brazil was assessed. Blood, heart, and brain from each chicken were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT> or =1:5) were found in 16 chickens. Hearts and brains of seropositive (MAT> or =1:5) chickens were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) chickens were bioassayed in two T. gondii-free cats (12 chickens per cat). T. gondii was isolated from 13 of 16 (81%) seropositive chickens. Of the two cats fed tissues pooled form seronegative chickens, one shed T. gondii oocysts. Nine of the 13 T. gondii isolates killed 100% of infected mice. The T. gondii isolate from the cat was also virulent for mice. Genotyping of 13 chicken isolates of T. gondii using the SAG2 locus indicated that seven isolates were type I and six were type III; three of these type III isolates killed all infected mice suggesting that all strains virulent for mice are not type I. The isolate from the feces of the cat fed chicken tissues was type I.     

Characteristics of pedigree cat breeding in the Netherlands: breeds, population increase and litter size

A survey of the Dutch Cat Fancy was carried out to determine reproductive, patterns of pedigree cats. The data of the present study were obtained by questioning the pedigree registers of the cat clubs participating in the foundation 'Overleg Platform van de Nederlandse Cat Fancy'. The Dutch Cat Fancy registers 34 different cat breeds. From 1992 up to 1996 a total of 25.985 litters were registered. Over this period the number of litters increased from 4989 to 5313. Litters from Longhair and Exotic Shorthair cats comprised the biggest group and accounted for 55% of the total number of litters. However, over this period, the number of Longhair and Exotic Shorthair litters decreased by 9%. Litters from British Shorthair, Birman, Maine Coon and Norwegian Forrest Cat increased in number as did litters from small breeds such as Ragdoll, Bengal and Sphynx. Litters from Abyssinian, Siamese, Oriental Shorthair cats remained relatively the same. The average litter size of the total cat population, based on pedigree certificates, was calculated at 3.3 kittens per litter. For different breeds litter size varied from 2.7 (Longhair and Exotic Shorthair) to 4.3 (Burmese and Maine Coon). Taking into account an average age of 14 years, the total Dutch pedigree cat population was estimated at 240,000 viz. about 10% of the total cat population.     

Congenital toxoplasmosis in Abyssinian cats

Two of three litter-mate kittens born to an Abyssinian cat died of acute toxoplasmosis. Toxoplasma gondii was found in histologic sections of both kittens and this was confirmed by immunoperoxidase staining.     

Antemortem diagnosis and treatment of toxoplasmosis in two cats on cyclosporin therapy

Clinical toxoplasmosis was diagnosed antemortem in two cats being treated with therapeutic doses of cyclosporin. The diagnosis was made by detecting tachyzoites on cytological examination of bronchoalveolar lavage fluid from one case and pleural effusion from the other. Despite early diagnosis and aggressive treatment in both cases, only one cat survived. Reactivation of latent Toxoplasma gondii infection secondary to cyclosporin-induced immunosuppression was considered likely in both cases. The presence of respiratory signs in cats treated with cyclosporin should alert clinicians to the possibility of clinical toxoplasmosis. Consideration should be given to determining the serostatus of cats to T gondii prior to use of drugs which are potent inhibitors of cell mediated immunity, such as cyclosporin. Two cases of feline toxoplasmosis are presented.     

Effect of Feline Immunodeficiency Virus Infection on Toxoplasma gondii-specific Humoral and Cell-mediated Immune Responses of Cats with Serologic Evidence of Toxoplasmosis

Serum samples from 89 cats with serologic evidence of toxoplasmosis were identified by using an enzyme-linked immunosorbent assay (ELISA) that detected Toxoplasma gondii -specific immunoglobulin M (IgM) or T. gondii -specific immunoglobulin G (IgG). Concurrent feline immunodeficiency virus (FIV) infection was detected in 36 cats using an ELISA for detection of FIV-specific IgG. The majority of the cats in both the FIV-seropositive and FIV-seronegative groups were male and >5 years of age. FIV-seropositive cats were more likely to have T. gondii IgM titers without IgG ( P > 0.05) or any T. gondii IgM titer ( P > 0.05) than were FIV-seronegative cats. FIV-seronegative cats (1328) had a higher T. gondii IgG geometric mean titer than did FIV-seropositive cats (724) and were more likely to have T. gondii IgG titers 1:2048 than were FIV-seropositive cats ( P > 0.05). Cats with serologic evidence of both T. gondii and FIV infections had persistent T. gondii IgM titers for >12 weeks. Lymphoblast transformation in response to concanavalin A, T. gondii -specific intracellular antigens, and T. gondii -specific secretory antigens was compared in T. gondii seropositive and FIV-seronegative cats, cats with serologic evidence of T. gondii infection alone, and cats with serologic evidence of concurrent FIV and T. gondii infections. Lymphocytes from all but one cat in the FIV-seropositive group responded to concanavalin A. Whereas lymphocytes from FIV-seronegative cats with serologic evidence of toxoplasmosis responded to T. gondii -specific antigens, four of five of the FIV-seropositive cats with concurrent serologic evidence of toxoplasmosis did not.     

Isolation and molecular characterization of Toxoplasma gondii from chickens and ducks from Egypt

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 121 free range chickens (Gallus domesticus) and 19 ducks (Anas sp.) from a rural area surrounding Giza, Egypt was assessed. Blood, heart, and brain from each animal were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT), were found in 49 (40.4%) chickens in titers of 1:5 in 11, 1:10 in four, 1:20 in four, 1:40 in eight, 1:80 in 10, and 1:160 or more in 12 chickens. Antibodies were found in three ducks each with a titer of 1:80. Hearts and brains of seropositive (MAT > or = 1:5) chickens and ducks were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) animals were bioassayed in T. gondii-free cats. T. gondii was isolated from 19 of 49 seropositive chickens (one with a titer of 1:5, two with a titer of 1:20, one with a titer of 1:40, five with a titer of 1:80, three with a titer of 1:160, and seven with a titer of > or = 1:360). One cat fed tissues pooled from 15 seronegative chickens shed T. gondii oocysts, while two cats fed tissues of 34 seronegative chickens did not shed oocysts. T. gondii was isolated from one of the seropositive ducks by bioassay in mice. The two cats fed tissues from 16 seronegative ducks did not shed oocysts. Genotyping of 20 chicken isolates of T. gondii using the SAG 2 locus indicated that 17 isolates were type III and three were type II. The duck isolate of T. gondii was type III. The mice inoculated with tissue stages of all 21 isolates of T. gondii from chickens and ducks remained asymptomatic, indicating that phenotypically they were not type I because type I strains are lethal for mice. Infections with mixed genotypes were not found.     

Unexpected oocyst shedding by cats fed Toxoplasma gondii tachyzoites: in vivo stage conversion and strain variation

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, irrespective of the dose. The conversion of bradyzoites to tachyzoites and tachyzoites to bradyzoites is biologically important in the life cycle of T. gondii. In the present paper, the pp was used to study in vivo conversion of tachyzoites to bradyzoites using two isolates, VEG and TgCkAr23. T. gondii organisms were obtained from the peritoneal exudates (pex) of mice inoculated intraperitoneally (i.p.) with these isolates and administered to cats orally by pouring in the mouth or by a stomach tube. In total, 94 of 151 cats shed oocysts after ingesting pex. The pp after ingesting pex was short (5-10 days) in 50 cats, intermediate (11-17) in 30 cats, and long (18 or higher) in 14 cats. The strain of T. gondii (VEG, TgCKAr23) or the stage (bradyzoite, tachyzoite, and sporozoite) used to initiate infection in mice did not affect the results. In addition, six of eight cats fed mice infected 1-4 days earlier shed oocysts with a short pp; the mice had been inoculated i.p. with bradyzoites of the VEG strain and their whole carcasses were fed to cats 1, 2, 3, or 4 days post-infection. Results indicate that bradyzoites may be formed in the peritoneal cavities of mice inoculated intraperitoneally with T. gondii and some bradyzoites might give rise directly to bradyzoites without converting to tachyzoites.     

Genotyping of Toxoplasma gondii isolates from chickens from India

The present study was undertaken to isolate and genotype Toxoplasma gondii from free-range chickens (Gallus domesticus) from villages in Maharashtra and Tamil Nadu states of central and south India, respectively. Blood, heart, and brain from a total of 741 chickens were examined for T. gondii infection. Antibodies to T. gondii, as assayed with the modified agglutination test (MAT >or = 1:5) were found in 133 (17.9%) chickens. Hearts and brains of 186 chickens were bioassayed in mice. Additionally, hearts and/or brains of most of the seronegative (MAT < 1:5) chickens were fed to 20 T. gondii-free cats, while 32 seropositive chickens (MAT 1:5) were fed to 3 cats. T. gondii was not isolated from any of the chickens by mouse bioassay. Five of the cats that were fed seronegative chickens shed oocysts, while isolates were not obtained from any of the other cats fed seropositive chickens. These five isolates, along with the two that were previously isolated in India through cat bioassay, were genetically analyzed. Genotyping using the SAG 2 locus indicated that two isolates were type II and five were type III. Microsatellite analysis revealed allelic differences between and within the lineages. This is the first report of genetic characterization of any T. gondii isolate from India.     

Prevalence of chlamydia, toxoplasma, toxocara and ringworm in farm cats in south-west England

The prevalence of infection with Chlamydia psittaci, Toxoplasma gondii, Toxocara cati and Microsporum canis was examined in 51 cats on 22 sheep farms in the Bristol area. Serum antibody to C psittaci and T gondii was present in 45 per cent and 47 per cent of cats, respectively. At the time of sampling C psittaci was isolated from 6 per cent of the cats, T cati was identified in 63 per cent of faecal samples but neither T gondii nor M canis was isolated. When examined according to the farm of origin, 22.7 per cent of farms had cat populations with no evidence of infection with C psittaci or T gondii. Of the remainder, 45.5 per cent supported cat populations with evidence of both infections and 31.8 per cent had evidence of T gondii infection alone. None of the farms had cat populations with evidence of C psittaci infection alone. Two of the cats infected with C psittaci were excreting viable organisms in the faeces. The possible significance of this to the epidemiology of ovine enzootic abortion is discussed.     

Reproductive capacity of free-roaming domestic cats and kitten survival rate

OBJECTIVE: To determine reproductive capacity of naturally breeding free-roaming domestic cats and kitten survival rate. DESIGN: Prospective cohort and retrospective cross-sectional study. ANIMALS: 2,332 female cats brought to a trap-neuter-return clinic for neutering and 71 female cats and 171 kittens comprising 50 litters from a cohort study of feral cats in managed colonies. PROCEDURE: Data collected for all cats included pregnancy, lactation, and estrus status and number of fetuses for pregnant cats. Additional data collected for feral cats in managed colonies included numbers of litters per year and kittens per litter, date of birth, kitten survival rate, and causes of death. RESULTS: Pregnant cats were observed in all months of the year, but the percentage of cats found to be pregnant was highest in March, April, and May. Cats produced a mean of 1.4 litters/y, with a median of 3 kittens/litter (range, 1 to 6). Overall, 127 of 169 (75%) kittens died or disappeared before 6 months of age. Trauma was the most common cause of death. CONCLUSIONS AND CLINICAL RELEVANCE: Results illustrate the high reproductive capacity of free-roaming domestic cats. Realistic estimates of the reproductive capacity of female cats may be useful in assessing the effectiveness of population control strategies.