Low virulence of oocysts of Czech Toxoplasma gondii isolates on the basis of biological and genetic characteristics

The virulence of the oocysts of 7 Czech Toxoplasma gondii isolates was tested. The oocysts were obtained by experimental infection of cats with the tissue cysts of T. gondii isolates from dogs, cats, and rabbits. The cats shed the oocysts in feces, with prepatent periods of 3-5 days postinfection (PI); the patent period was 7-18 days. The number of oocysts shed varied between 0.94 million and 47 million, with 0.66 million-39 million oocysts found in the daily samples of excrement. The cats ceased oocyst production at 11-22 days PI. Sporulated oocysts were used to prepare infective doses of 1 to 10(5) oocysts for oral infection of 10 mice. Deoxyribonucleic acid isolated from 4 T. gondii isolates was used in polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for amplification of the ROP1 gene and restriction of the product of amplification by restriction endonuclease DdeI. On the basis of their biological characteristics, all 7 isolates belonged to the group of "avirulent" strains. In the PCR-RFLP tests, 2 isolates, K9 and K19, showed an "avirulent" strain pattern.     

High prevalence of toxoplasmosis in cats from Egypt: isolation of viable Toxoplasma gondii, tissue distribution, and isolate designation

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that excrete environmentally resistant oocysts in feces. In the present study, 158 feral cats from Giza, Egypt, were examined for T. gondii infection. Antibodies to T. gondii were found in 97.4% with the modified agglutination test. Viable T. gondii was isolated from tissues (brain, heart, tongue) of 115 of 137 cats by bioassay in mice. These isolates were designated TgCatEg 1-115; none of these isolates was virulent to out-bred Swiss Webster mice. Of the 112 seropositive cats whose tissues were bioassayed individually, T. gondii was isolated from the hearts of 83 (74.1%), tongues of 53 (47.3%), and brains of 36 (32.1%). Toxoplasma gondii oocysts were not detected in rectal contents of any of the 158 cats, probably related to high seropositivity (chronic infection) of cats surveyed. The high prevalence of T. gondii in feral cats in Egypt reported here indicates a high environmental contamination with oocysts.     

Prevalence of Cryptosporidium Infection among Inhabitants of 2 Rural Areas in White Nile State,Sudan

Cryptosporidium , a protozoan parasite that causes watery diarrhea, is found worldwide and is common in areas with low water hygiene. In February 2014, 866 stool samples were collected from the inhabitants of 2 rural areas in White Nile State, Sudan. These stool samples were assessed by performing modified acid-fast staining, followed by examination under a light microscope. The overall positive rate of Cryptosporidium oocysts was 13.3%. Cryptosporidium oocysts were detected in 8.6% stool samples obtained from inhabitants living in the area having water purification systems and in 14.6% stool samples obtained from inhabitants living in the area not having water purification systems. No significant difference was observed in the prevalence of Cryptosporidium infection between men and women (14.7% and 14.1%, respectively). The positive rate of oocysts by age was the highest among inhabitants in their 60s (40.0%). These findings suggest that the use of water purification systems is important for preventing Cryptosporidium infection among inhabitants of these rural areas in Sudan.     

Toxoplasma gondii B1 Gene Detection in Feces of Stray Cats around Seoul,Korea and Genotype Analysis of Two Laboratory-Passaged Isolates

The increasing prevalence of Toxoplasma gondii infection in the human population in the Republic of Korea (= Korea) is due to various reasons such as an increase in meat consumption. However, the importance of cats in transmitting T. gondii infection through oocysts to humans has seldom been assessed. A total of 300 fecal samples of stray cats captured around Seoul from June to August 2013 were examined for T. gondii B1 gene (indicating the presence of oocysts) using nested-PCR. Fourteen (4.7%) of 300 cats examined were positive for B1 gene. Female cats (7.5%) showed a higher prevalence than male cats (1.4%). Cats younger than 3 months (5.5%) showed a higher prevalence than cats (1.5%) older than 3 months. For laboratory passage of the positive samples, the fecal suspension (0.2 ml) of B1 gene positive cats was orally inoculated into experimental mice. Brain tissues of the mice were obtained after 40 days and examined for the presence of tissue cysts. Two isolates were successfully passaged (designated KNIH-1 and KNIH-2) and were molecularly analyzed using the SAG5D and SAG5E gene sequences. The SAG5D and SAG5E gene sequences showed high homologies with the ME49 strain (less virulent strain). The results indicated the importance of stray cats in transmitting T. gondii to humans in Korea, as revealed by detection of B1 gene in fecal samples. T. gondii isolates from cats were successfully passaged in the laboratory for the first time in Korea.     

Antibody kinetics and exposure to Toxoplasma gondii in cats: a seroepidemiological study

Domestic cats are the most important definitive hosts for Toxoplasma gondii, the agent of an important global zoonosis. Serial sera from cats orally inoculated either with T. gondii tissue cysts (n = 3) or sporulated oocysts (n = 3) and from 65 client-owned cats, plus sera from 1,757 client-owned cats presented to veterinarians in Switzerland were analysed for an antibody response to T. gondii by ELISA. Risk factors for seropositivity and prevalence were estimated with a generalised linear and beta regression model. The first model examined the association of an OD₄₀₅ value as the dependent variable, with gender, age, and outside access as possible independent variables. In the second model, we first analysed the data assuming a bimodal distribution representing two overlapping distributions of OD₄₀₅ values from positive and negative cats, enabling the assignment of a probability of true infection status to each cat. Mean probabilities of true infection status across groups represent an estimate of true prevalence. These probabilities were then regressed against age, gender and outside access. Antibody kinetics in cats orally inoculated with tissue cysts, shedding oocysts, did not differ significantly from those of cats inoculated with sporulated oocysts without detectable oocyst excretion, suggesting extraintestinal parasite invasion and exposure to tachyzoites in both situations at an early stage of infection. Analysis of serial serum samples suggested a persisting long-term humoral immune response. Of the client-owned cats, 42.4% (95% confidence interval (CI): 40.1–44.6) had a positive true infection status. This was higher (56.3% (95% CI: 53.2–59.6)) in cats with outside access than in those without (22.1% (95% CI: 18.9–25.4)). In the first model, the factors age (P < 0.0001), gender (male: P = 0.046), and outside access (P < 0.0001) were independently associated with significantly higher OD₄₀₅ values. In the second model, the probability of having a positive true infection status increased with age (P < 0.0001), was higher with outside access (P < 0.0001) and in outdoor male cats (P = 0.0006).     

Seroprevalence of Toxoplasma gondii antibodies in domestic cats from Barcelona, Spain

Cats are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete the environmentally resistant oocysts. Antibodies to T. gondii were determined in serum samples from 220 domestic cats (Felis catus) from Barcelona, Spain, using the modified agglutination test (MAT). Antibodies to T. gondii were found in 99 (45%) of 220 cats, with MAT titers of 1:25 in 26, 1:50 in 57, and > or = 1:500 in 16 cats. Seropositivity (MAT 1:25 or more) was significantly higher in adult (> or = 1 yr old, 49.7% of 153) than in juvenile (< 1 yr old, 34.3% of 67) cats, in feral (51.9% of 131) than in domiciled (34.8% of 89) cats, and in cats living in a group (community) of more than 5 cats (50.7% of 142) than in cats living alone (28.0% of 50). These seropositive cats are likely to have already shed T. gondii oocysts in the environment around Barcelona.     

Experimental Toxoplasmosis in Chimpanzees

Two chimpanzees were given by mouth large numbers of viable oocysts of Toxoplasma gondii obtained from the faeces of experimentally infected cats. Before the experiment the first chimpanzee had a positive dye test reaction (1:250), an indication that it had undergone an earlier infection of toxoplasmosis; the serum antibody titres remained unchanged, no evidence of illness was found, and oocysts did not appear in its faeces during the subsequent six weeks. The second chimpanzee showed a negative dye test reaction before infection, and this converted to positive on the 7th day, rose to a peak on the 35th day, and remained high for six months. This animal appeared unwell during the first week, and on the 7th day its blood proved infective to mice; on the 40th day the lymph nodes became enlarged and biopsy specimens of a node and muscle in the 11th week were also infective to mice. No oocysts were passed in the faeces. The presumed cycle in the chimpanzee and in man and the relationships between Toxoplasma and Isospora are discussed.     

Molecular characterization of Toxoplasma gondii isolates from cats in Spain

Cats are important in the epidemiology of Toxoplasma gondii because felids are the only definitive hosts that can excrete environmentally resistant oocysts. Fresh samples of brain from 103 Spanish cats with antibodies to T. gondii were analyzed for T. gondii DNA using nested-PCR; 47 (45.5%) were found to be positive. Further characterization of DNA from 46 cats using RFLP-PCR at the 3' and 5' ends of the SAG2 locus revealed that 12 (26%) isolates were Type I and 34 (74%) were Type II; no Type III were found, and the 47th sample could not be classified to its genetic type. In addition, T. gondii was also isolated by bioassay in mice from 42 of 103 seropositive cats. This is the first report of T. gondii characterization from cats in Spain.     

A field trial of the effectiveness of a feline Toxoplasma gondii vaccine in reducing T. gondii exposure for swine

A 3-yr field trial was conducted on 8 commercial swine farms in Illinois to determine the effectiveness of a feline Toxoplasma gondii vaccine in reducing the exposure of swine to T. gondii. A vaccine consisting of live bradyzoites of the mutant T-263 strain, capable of preventing oocyst shedding by cats, was used in this study. Each farm was visited 3 times in 1994, 3 times in 1995, and once in 1996. Cats were trapped and inoculated with the T-263 oral vaccine during 1994 and 1995. On each visit, the following samples were collected: blood from pigs, cats, and mice for detection of serum antibodies to T. gondii, feces from cats to detect oocysts, and heart and brain tissues from rodents to determine the presence of T. gondii tissue cysts. The modified agglutination test (MAT), with a positive titer set at the 1:25 dilution, was used to determine serum antibodies. At first capture, 72.6% (61/84) of juvenile cats and 32.6% (31/95) of adult cats had no detectable antibodies (seronegative), indicating no prior exposure to T. gondii when they received their first vaccine. Of these first-time seronegative cats, 58.1% (18/31) of adult and 45.9% (28/61) of juvenile cats were recaptured and received a second dose of vaccine. Changes in the prevalence of T. gondii infection were evaluated from the prevaccination (1992, 1993) to the postvaccination (1996) period. Eleven cats (5%) were detected shedding oocysts between 1994 and 1996, of which 10 (90.1%) shed during 1994. The last detection of oocyst shedding by cats was during the first farm visit in 1995. There was a significant decrease in T. gondii seroprevalence for finishing pigs (P < 0.05, Wilcoxon sign rank test). There was a positive correlation (Spearman's p = 1.0, P < 0.0001) between the change in prevalence in juvenile cats and the change in prevalence in finishing pigs. The seropositivity rate (MAT > or = 1:25) in mice among all farms decreased from 4% in 1992-1993 to 0% in 1996. The mean prevalence of T. gondii tissue cyst isolation for mice on all farms decreased from 1.1% in 1994, to 0.8% in 1995, and to 0.5% in 1996. The results of this study suggest that the reduced exposure of pigs to T. gondii was due to the administration of the T. gondii vaccine to cats.     

Isospora Species of the Cat and Attempted Transmission of I. felis Wenyon, 1923 from the Cat to the Dog*

SYNOPSIS Fecal samples from 130 domestic cats from Illinois were examined for coccidia. Three species of Isospora were found: (1) I. felis Wenyon, 1923, with oocysts 38-51 by 27-39 μ with a mean of 41.6 by 30.5 μ and sporocysts 20-26 by 17-22 μ with a mean of 22.6 by 18.4 μ; it was found in 13% of the cats; (2) I. rivolta (Grassi, 1879) Wenyon, 1923, with oocysts 21-28 by 18-23 μ with a mean of 25.0 by 21.1 μ, and sporocysts 14-16 by 10-13 μ with a mean of 15.2 by 11.6 μ; it was found in 3% of the cats; and (3) I. bigemina (Stiles, 1891) Lühe, 1906, with oocysts 12-15 by 10-13 μ with a mean of 13.2 by 11.8 μ. and sporocysts 8-10 by 6-8 μ with a mean of 8.8 by 6.5 μ it was found in 1.5% of the cats. Four coccidia-free puppies 1.5 months old were inoculated with 100,000 oocysts each of I. felis from the cat, but patent infections did not occur. Partial development of I. felis was not seen in tissue sections of the small intestine of a 5th pup killed 96 hours after inoculation with 150,000 I. felis oocysts. This coccidium is therefore presumably host-specific.     

Feline Toxoplasmosis from Acutely Infected Mice and the Development of Toxoplasma Cysts*

SYNOPSIS. The development of Toxoplasma cysts was studied in mice inoculated with tachyzoites by several routes. After 1–30 days of infection, murine tissues were examined microscopically, and portions or whole carcasses were fed to mice and cats. The feces of the cats were examined for oocyst shedding. Cyst-like structures containing distinct PAS-positive granules were first seen after 3 days of infection with tachyzoites, and became numerous by 6 days. Argyrophilic walls were first seen after 6 days, and became numerous by 16 days of infection with tachyzoites. Prepatent periods to oocyst shedding (PPO) were either “short” (3–10 days) or “long” (19–48 days). The “short” PPO was found only in cats that had ingested mice infected for 3 days or longer, and was related to the development of PAS-positive granules in T. gondii, and to high, 60–100%, oral infectivity rates for cats. The “long” PPO followed the ingestion of mice infected for only 1–2 days, and was related to tachyzoites without distinct PAS-positive granules and low, 32% or less, infectivity for cats. The “long” PPO followed also the ingestion of oocysts and the parenteral inoculation of tachyzoites, bradyzoites, or sporozoites. Using the “short” PPO as a criterion for detecting cysts in tissues, it was shown that (a) numerous cysts developed in mice 5 days after inoculation with tachyzoites, 7–9 days after inoculation with cysts, and 9–10 days after inoculation with oocysts, and (b) cysts developed faster and more frequently in the brain and muscle than in lungs, liver, spleen, and kidneys of mice inoculated with tachyzoites.     

PCR-Based Molecular Characterization of Toxocara spp. Using Feces of Stray Cats: A Study from Southwest Iran

Feces of stray cat are potential sources of gastrointestinal parasites and play a crucial role in spreading and transmitting parasite eggs, larvae, and oocysts through contamination of soil, food, or water. In this study, we investigated the prevalence of Toxocara spp. infection in stray cats in Ahvaz city, southwest Iran. Eggs of Toxocara spp. in feces of stray cats were detected by the sucrose flotation method, and identification was conducted by polymerase chain reaction (PCR) and DNA sequencing. Of the 140 fecal samples that were randomly collected from public environments during the months of January to May 2012, 45% were found to harbour Toxocara spp. eggs. The highest prevalence of Toxocara spp. eggs was found in the central area of Ahvaz city (28.6%). T. canis eggs were found in 4 (6.34%) of the 63 positive samples. Stray cats are found in parks, playgrounds, and other public places and may be a potential contamination risk. Identification of Toxocara spp. using molecular methods is sufficiently sensitive to detect low levels of parasites and identify the different Toxocara spp. in feces. The relatively high prevalence of Toxocara spp. infection may continue to increase due to lack of effective environmental hygiene control in Iran. Consequently, there is a need to plan adequate programs to detect, identify, and control this infection as well as stray cats in the region.     

Epizootic outbreaks of trichinosis in 2 pig farms from the Metropolitan Region of Chile

In Chile swine trichinosis has presented a progressive decreasing in the last two decades of XX century. T. spiralis pig infection descended from an average of 0.683 per 1000 in 1980-1984 to 0.315 in 1985-1989 and to 0.115 in 1990-1996. In the particular case of Metropolitan Region this decreasing has been more marked: from an average of 0.058 per 1000 in 1990-1994 to 0.003 in 1995-1999. Between the end of June 1999 and middle January 2000 in Metropolitan Region abattoirs T. spiralis was detected in 15 (4.9%) out of 306 swine from two pigsties located in El Monte (E.M.) and Padre Hurtado (P.H.) 45 and 30 km south-west from Santiago. In the same period another four pigs from the same premises were found infected in abattoirs of other regions. During inspection visits it was stated that both pig farms had deficient sanitary conditions. Phototrichinoscopy was positive in three out of five Rattus norvegicus collected in E.M. In pigsty PH the examination of diaphragm samples of 25 dogs and 17 cats resulted negative. In the premises originating T. spirali infected swine the Metropolitan Environmental Health Service Abattoirs Program carries out an epidemiological vigilance consisting in the follow-up of animals destined for slaughtering in order to initiate prophylactic actions oriented to eliminate eventual sources of trichinosis infection for human and rearing pigs.     

Prevalence of Dirofilaria immitis Infection in Stray Cats by Nested PCR in Korea

The purpose of this study was to conduct a survey of Dirofilaria immitis infection among stray cats in Korea using nested PCR. We included 235 stray cats (121 females and 114 males) and evaluated each for the presence of feline heartworm infection. Blood samples were collected from 135 cats in Daejeon, 50 cats in Seoul, and 50 cats from Gyeonggi-do (Province). Of the 235 DNA samples, 14 (6.0%) were positive for D. immitis. The prevalence of infection in male cats (8/114, 7.0%) tended to be higher than that in female cats (6/121, 5.0%), but the difference was not statistically significant. In each location, 8, 2, and 4 cats were positive for infection, respectively, based on DNA testing. No significant differences in the prevalence were observed among the geographic regions, although the rate of infection was higher in Gyeonggi-do (8.0%) than Daejeon (5.9%) and Seoul (4.0%). We submitted 7 of the 14 D. immitis DNA-positive samples for sequencing analysis. All samples corresponded to partial D. immitis cytochrome c oxidase subunit I gene sequences with 99% homology to the D. immitis sequence deposited in GenBank (accession no. {"type":"entrez-nucleotide","attrs":{"text":"FN391553","term_id":"295980069","term_text":"FN391553"}}FN391553). To the best of our knowledge, this is the first survey using nested PCR to analyze the prevalence of D. immitis in stray cats in Korea.     

Studies on coccidiosis in guinea pigs. 2. Epizootiological survey

An epizootiological survey has been carried out on naturally occurring coccidiosis in Hartley guinea pigs (weight, 250g) purchased by the National Institute of Health, Tokyo during the period 1964 to 1982. Coccidial infections in breeding colonies of guinea pigs were observed very frequently in weaned animals but scarcely in adult and suckling animals. Oocysts of Eimeria caviae were detected in 53.8% of the 7,162 fecal samples collected from transportation boxes and coccidiosis occurred in 39% of the 1,461 dead or culled animals obtained during the routine one week quarantine period. In the period 1964 to 1971, particularly high rates of prevalence of oocysts, between 55-86%, and incidence of coccidiosis, between 55-76%, were observed. These rates were clearly reduced in the period 1972 to 1982, with a lower rate of isolation of oocysts ranging from 14-48% and les than 20% incidence of coccidiosis (except in 1981 and 1982). The monthly fluctuation of occurrence rates of oocysts and clinical coccidiosis differed over the period of study. From 1964 to 1971, the high prevalence of oocysts was consistently observed accompanied by a bimodal pattern of incidence of coccidiosis in April (85%) and October (78%). In the period 1972 to 1982, both parameters showed a single peak, for prevalence of oocysts in June (60.7%) and for incidence of coccidiosis in May (45%). Oocysts in feces disappeared in February and March and coccidiosis occurred irregularly in 1981 and 1982.(ABSTRACT TRUNCATED AT 250 WORDS)     

High prevalence of viable Toxoplasma gondii infection in market weight pigs from a farm in Massachusetts

The ingestion of uncooked infected meat is considered important in the epidemiology of Toxoplasma gondii infection in humans and little is known of the prevalence of viable T. gondii in meat used for human consumption in the United States. In the present study, viable T. gondii was isolated from 51 out of 55 pigs destined for human consumption. Hearts and tongues (500 g) from fifty-five 6-mo-old pigs from a farm in Massachusetts were bioassayed for T. gondii by feeding them to T. gondii-free cats. Feces of these cats were examined for shedding of T. gondii oocysts. Fifty-one of 55 cats fed pig tissues each shed 25-810 million T. gondii oocysts in their feces. Two of these cats consumed tissues of pigs that were shown to be seronegative with the Sabin-Feldman dye test, the modified agglutination test, and the Western blot. Results indicate that until examination of meat for T. gondii infection is implemented in slaughterhouses, all meat should be cooked according to industry guidelines before human consumption.     

Prevalence of viable Toxoplasma gondii in beef, chicken, and pork from retail meat stores in the United States: risk assessment to consumers

The prevalence of viable Toxoplasma gondii was determined in 6,282 samples (2,094 each of beef, chicken, and pork) obtained from 698 retail meat stores from 28 major geographic areas of the United States. Each sample consisted of a minimum of 1 kg of meat purchased from the retail meat case. To detect viable T. gondii, meat samples were fed to T. gondii-free cats and feces of cats were examined for oocyst shedding. Initially, 100 g of meat from 6 individual samples of a given species were pooled (total, 600 g), fed to a cat over a period of 3 days, and feces were examined for oocysts for 14 days; the remaining meat samples were stored at 4 C for 14 days (until results of the initial cat fecal examination were known). When a cat fed pooled samples had shed oocysts, 6 individual meat samples from each pool were bioassayed for T. gondii in cats and mice. Toxoplasma gondii isolates were then genetically characterized using the SAG2 locus and 5 hypervariable microsatellite loci. In all, 7 cats fed pooled pork samples shed oocysts. Toxoplasma gondii oocysts were detected microscopically in the feces of 2 of the cats; 1 isolate was Type II and the second was Type III. Analyzed individually, T. gondii was detected by bioassay in 3 of the 12 associated samples with genetic data indicating T. gondii isolates present in 2. The remaining 5 pooled pork samples had so few oocysts that they were not initially detected by microscopic examination, but rather by mouse bioassay of cat feces. Two were Type I, 1 was Type II, and 2 were Type III. None of the cats fed chicken or beef samples shed oocysts. Overall, the prevalence of viable T. gondii in retail meat was very low. Nevertheless, consumers, especially pregnant women, should be aware that they can acquire T. gondii infection from ingestion of undercooked meat, and in particular, pork. Cooking meat to an internal temperature of 66 C kills T. gondii.     

Prevalence of feline viral antibodies in random-source laboratory cats

Over a period of 1973 to 1979, a serologic survey of virus infections was conducted on feline sera collected in four universities which located in different prefectures; Obihiro, Saitama, Kanagawa and Tokyo. A significant hemagglutination-inhibition (HI) antibody titer of 1 : 8 or higher to feline panleukopenia virus (FPLV) was detected in 130 (58%) of the 226 sera used. No remarkable difference in the HI antibody prevalence in cats to FPLV was recognized by years or localities. Of a total of 188 cats tested, 99 (53%) presented positive serum neutralizing (SN) antibody titers to the No. 1 strain of feline calicivirus (FCV). Especially in Kanagawa, 17 (77%) of the 22 cats had positive SN titers. However, only 42 (22%) of the 188 sera showed positive SN titers to the Kyoritsu strain of FCV. Such lower positivity in the cats was observed with 13% in the SN test to human reovirus type 3 (Reo-3). The incidence of positive SN antibodies to feline rhinotracheitis virus (FRV) also remained in low values of 20 to 27% with the exception of high percentage of 86 in Tokyo. The dissemination of FPLV, FRV, FCV and Reo-3 was briefly discussed in relation with the age distribution of viral antibodies in cats.     

Toxoplasma gondii isolates from free-ranging chickens from the United States

Prevalence of Toxoplasma gondii infection in chickens is a good indicator of the strains prevalent in their environment because they feed from ground. The prevalence of T. gondii was determined in 118 free-range chickens from 14 counties in Ohio and in 11 chickens from a pig farm in Massachusetts. Toxoplasma gondii antibodies (> or = 1: 5) were found using the modified agglutination test (MAT) in 20 of 118 chickens from Ohio. Viable T. gondii was recovered from 11 of 20 seropositive chickens by bioassay of their hearts and brains into mice. The parasite was not isolated from tissues of 63 seronegative (< or = 1:5) chickens by bioassay in cats. Hearts, brains, and muscles from legs and breast of the 11 chickens from the pig farm in Massachusetts were fed each to a T. gondii-negative cat. Eight cats fed chicken tissues shed oocysts; the 3 cats that did not shed oocysts were fed tissues of chickens with MAT titers of 1:5 or less. Tachyzoites of 19 isolates of T. gondii from Ohio and Massachusetts were considered avirulent for mice. Of 19 isolates genotyped, 5 isolates were type II and 14 were type III; mixed types and type I isolates were not found.     

Frequency of anti-Toxoplasma gondii antibodies in cats from Valdivia city, Chile

Toxoplasmosis is a parasitic zoonosis. The importance of the cat as related to this parasitosis lies in the fact that it is not only the definite host of the parasite, but responsible for its dissemination through the release of oocysts, which subsequently infect both humans and other animals. The objective of this study was to determine the serological prevalence of Toxoplasma gondii in the feline population of the city of Valdivia (Chile) and to establish the possible epidemiological implications of this prevalence. With these goals in mind the technique of indirect immunofluorescence was implemented to detect anti- T. gondii species--specific IgG. Blood samples from 97 cats (selected using a directed sampling process) from different sectors of Valdivia were collected. The sample included 46 males and 51 females of different ages, Positive and negative control sera obtained from de United States were used to verify the results, observed by UV microscopy. The anti-feline IgG antibody was used as directed by the manufacturer (Sigma). Of the 97 selected cats, 32 were found to be positive with a titre higher than 1:4, a prevalence of 33.0%. The number of infected males as compared to the number of infected females was found to be statistically insignificant, using the chi-square analysis with p less than 0.1. In contrast, a definite correlation between age and seropositivity was found; infection levels were higher in older animals. These results are consistent with those obtained in different studies on this topic that have been performed in different parts of the world. However, they would seem to be in conflict with other, similar studies that have been done recently in Chile; this may be due to the fact that the cats selected for this study were exposed to different climatic conditions than those examined in previous works. In conclusion, it has been determined that in Valdivia exist cats infected by T. gondii, which indicate the presence of the necessary epidemiological conditions for the persistence of this parasitic cycle and the source of infection for humans and other animals.