Toxoplasma gondii in semen of experimentally infected swine

Oral Sex as a Potential Route for Toxoplasma Gondii Transmission: Experiment with Human Semen and Laboratory Mice Model

PURPOSE

Toxoplasma gondii is one of the most widespread parasites in the human population globally. Several modes of its transmission have been proposed: some are well-researched and confirmed, others remain unconfirmed. One unconfirmed hypothesis pertains to potential transmission of Toxoplasma gondii via oral sex (fellatio) in humans. A recent study found tissue cysts in the semen of men with latent toxoplasmosis. Therefore, we aimed to test the hypothesis of Toxoplasma gondii transmission through oral sex experimentally.

METHODS

Eighty-two laboratory mice were orally administered semen samples from 41 men with latent toxoplasmosis. These semen samples were examined for the presence of Toxoplasma gondii DNA using PCR.

RESULTS

We detected Toxoplasma gondii DNA in three of the 41 semen samples from men with latent toxoplasmosis. Oral administration of semen samples to laboratory mice did not result in parasite transmission.

CONCLUSION

We have not demonstrated the transmission of Toxoplasma to mice by oral exposure to semen from infected men. While this does not conclusively rule out the possibility of such transmission in humans, the results suggest that, if it does occur, this mode of transmission is likely infrequent.

Toxoplasma gondii infection and testosterone alteration: A systematic review and meta-analyses

BACKGROUND

Toxoplasma gondii (T. gondii) is a worldwide distributed protozoan parasite which has infected a wide range of warm-blooded animals and humans. The most common form of T. gondii infection is asymptomatic (latent); nevertheless, latent toxoplasmosis can induce various alterations of sex hormones, especially testosterone, in infected humans and animals. On the other hand, testosterone is involved in behavioral traits and reproductive functions in both sexes. Hence, the purpose of this systematic review is to summarize the available evidence regarding the association between T. gondii infection and testosterone alteration.

METHODS

In the setting of a systematic review, an electronic search (any date to 10 January 2023) without language restrictions was performed using Science Direct, Web of Science, PubMed, Scopus, and Google Scholar. The PRISMA guidelines were followed. Following the initial search, a total of 12,306 titles and abstracts were screened initially; 12,281 were excluded due to the lack of eligibility criteria or duplication. Finally, 24 articles met the included criteria. A mean±standard deviation (SD) was calculated to assess the difference of testosterone between T. gondii positive and T. gondii negative humans. The possibility of publication bias was assessed using Egger's regression. P-value < 0.05 was considered statistically significant.

RESULTS

This systematic review identified 24 articles (18 studies in humans and six studies in animals). Most human studies (13 out of 19) reported an increased level of testosterone following latent toxoplasmosis in males, while three studies reported decreased levels and two studies reported an insignificant change. Eleven articles (seven datasets in males and seven datasets in females) were eligible to be included in the data synthesis. Based on the random-effects model, the pooled mean± SD of testosterone in T. gondii positive than T. gondii negative was increased by 0.73 and 0.55 units in males and females, respectively. The Egger's regression did not detect a statistically significant publication bias in males and females (p = value = 0.95 and 0.71), respectively. Three studies in male animals (rats, mice, and spotted hyenas) and two studies in female animals (mice and spotted hyenas) reported a decline in testosterone in infected compared with non-infected animals. While, one study in female rats reported no significant changes of testosterone in infected than non-infected animals. Moreover, two studies in male rats reported an increased level of testosterone in infected than non-infected animals.

CONCLUSIONS

This study provides new insights about the association between T. gondii infection and testosterone alteration and identifies relevant data gaps that can inform and encourage further studies. The consequence of increased testosterone levels following T. gondii infection could partly be associated with increased sexual behavior and sexual transmission of the parasite. On the other hand, declining testosterone levels following T. gondii infection may be associated with male reproductive impairments, which were observed in T. gondii-infected humans and animals. Furthermore, these findings suggest the great need for more epidemiological and experimental investigations in depth to understand the relationship between T. gondii infection and testosterone alteration alongside with future consequences of testosterone alteration.

Impact of latent toxoplasmosis on the fertility indices of male rats

Infertility is a prevalent condition affecting approximately 70 million people worldwide and male factor contributes to about fifty percent of the issues. Studies on infectious agents as a possible cause of infertility has become prominent in the past decade. Toxoplasma gondii has emerged as a prime candidate as it has been found in the reproductive organs and semen of males of many animal species and humans. The aim of this study is to assess the effect of latent toxoplasmosis on experimental rat fertility. Ninety Toxoplasma infected rat were used as the experimental group besides, thirty control naïve ones. Both groups were observed clinically. Weekly assessment of fertility indices starting from the 7th week post infection till the 12th week were done by recording rat body weight, weight of testes, semen analysis and histo-morphometric analysis of the testes. Toxoplasma infected rats exhibited significant gradual loss of body weight and the absolute weight of the testes. The sperm characteristic parameters including percentage of motile sperm, percentage of viable sperm and sperm concentration in Toxoplasma infected rats showed highly significant decrease throughout the observation period in comparison to the control group with recording highly significant increase in the percentage of abnormal sperm forms. Pathological insults in tests of the infected rat group were denoted. Our findings demonstrated that Toxoplasma gondii is accused for affecting male rat main reproductive parameters and is implicated in the male reproductive disorders.

Presence of Trypanosoma vivax DNA in cattle semen and reproductive tissues and related changes in sperm parameters

The present work investigated the presence of Trypanosoma vivax in semen and reproductive tissues of experimentally infected cattle and evaluated changes in seminal parameters. Two groups of cattle were established: T01 - experimentally infected with T. vivax (n = 8) and T02 - not experimentally infected with T. vivax (n = 8). After infection, blood (every seven days until 182 days post-infection - DPI), semen (7, 14, 35, 56, 70, 120 and 182 DPI) and reproductive tissue (after euthanasia, 182 DPI) were collected to search for T. vivax using different techniques, including PCR, Woo and Brener. Seminal parameters, including turbulence, motility, concentration, and vigor, were also analyzed. Packed cell volume (PCV) of the animals was determined weekly and weight gain was calculated. The PCR revealed T. vivax DNA in 7/56 semen samples of post-infection T01 cattle. Trypanosoma vivax DNA was detected in the semen of 5/8 animals at 7, 14, 56, 70 and 120 DPI, in the testis of four, and in the epididymis and fat located around the testis of two others. Trypomastigote forms of T. vivax were not found in any semen sample. Sperm of T01 cattle had lower turbulence (p ≤ 0.05) at 7, 14, 35, 56, 120 and 182 DPI, lower vigor (p ≤ 0.05) at 120 DPI and more sperm abnormalities (p ≤ 0.05) than T02. Digital dermatitis was observed among T01 cattle. Animals of T01 had lower PCV values than did those of T02 for most of the evaluations performed and T02 animals gained more weight during the experiment. The results highlight the presence of T. vivax DNA in semen of infected cattle and the importance of this disease for male breeding cattle. Further research is needed to determine whether T. vivax can be sexually transmitted in cattle.

Epidemiology of Toxoplasmosis among the Pakistani Population: A Systematic Review and Meta-Analysis

Toxoplasma gondii is an intracellular obligate parasite that causes toxoplasmosis, a zoonotic infection that affects warm-blooded animals and humans worldwide. To comprehensively characterize the disease condition in Pakistan for future reference, we ascertained the prevalence of Toxoplasma infection and predisposing factors in the Pakistani population over a 20-year period. We systematically reviewed research articles published in English (2000−2020) from PubMed and Google Scholar. The search results 26 publications involving 10,924 people and 2611 seropositive cases. The toxoplasmosis seropositivity rate was higher in women (25.44%) as compared to men (21.48%) and were statistically significant (p < 0.001). Furthermore, seropositivity was high among people with direct contact with cats, who consumed uncooked meat and raw vegetables, had poor education, and lived in rural areas. The 35−65-year age group had the highest prevalence rate of T. gondii infection. Toxoplasma infection was significantly more prevalent in Khyber Pakhtunkhwa province (25.87%) than in Punjab (20.42%) (p < 0.001). This is the first comprehensive analysis of T. gondii infection epidemiology in Pakistan. It reveals a high frequency of infection among women. We strongly encourage further research to aid patient care and the development of more efficient diagnostic tests and preventative techniques.

Effects of Toxoplasma gondii on Sperm Parameters and Histomorphometry of Testis in Experimentally Infected Rats

Background: Toxoplasma gondii, an obligate intracellular parasite, can be involved in the infection of the male reproductive system. Objectives: Since more than a third of the human population and an increasing number of couples with idiopathic infertility are affected by toxoplasmosis, there is a necessity to evaluate the effects of T. gondii on the reproductive system. Methods: In this experimental study, detailed description of sperm parameters, hormone levels (testosterone, follicular stimulating factor [FSH], and luteinizing hormone [LH]), and histomorphometric analysis were gathered every 10 days on T. gondii infected Wistar male rats until day 80. Data on testis and body weight were also collected. Results: Sperm parameters (motility, viability, count, and normal sperms) as well as LH level were significantly lower in infected rats. No significant decrease was observed in FSH and testosterone levels. The number of Leydig cells significantly decreased on day 20. Significant reduction of Sertoli cells was also detected on day 60. Bodyweight reduced significantly on days 20 and 60, but the testis weight was elevated. Conclusions: T. gondii infection can lead to diminished fertility parameters, but not sterility in rats. The parasite could temporarily interfere with the male reproductive system.

A longitudinal study of Toxoplasma gondii seroconversion on four large Danish sow farms

Serological tests are routinely used to detect Toxoplasma gondii specific IgG antibodies in serum. Serological surveys of T. gondii show a medium to high prevalence in Danish indoor sows at the time of slaughter. However, little is known about when sows acquire T. gondii, and for how long they remain seropositive. Our focus was on quantifying the incidence rates in different age-cohorts and on investigating the T. gondii IgG antibody dynamics in sows. Four large Danish sow farms were longitudinally surveyed for 1 year. A total of 320 animals from 6, 12, 18, and 24-months age-cohorts were sampled at 5-week intervals. In total, 2989 plasma samples were tested using commercial enzyme linked immunosorbent assay (ELISA). The incidence rate in each of the four age-cohorts was calculated, and a time-to-event analysis was applied to the interval censored data to investigate the relationship between age and probability of T. gondii seroconversion. In the initial ELISA testing, eight sows tested positive for T. gondii at first survey, of which seven remained seropositive throughout the follow-up period. Additionally, 16 sows seroconverted, but only five of these remained seropositive. Weekly incidence rates in the 6, 12, 18, and 24-month age-cohorts were 0.0017 (95% CI = 0.0008 - 0.0037), 0.0009 (95% CI = 0.0003 - 0.0027), 0.0003 (95% CI = 0.0000 - 0.0018), and 0.0023 (95% CI = 0.0010 - 0.0051), respectively. Time-to-event analysis suggested that the incidence rate increased with age but could not conclude this definitively. The retesting of a subsample of the sows (n = 200) with the same ELISA and with modified direct agglutination test (MAT), and western blot (WB) assays suggested that 12 out of the 24 initial ELISA seropositive sows may have been false positive. These 12 sows also showed fluctuating antibody dynamics in ELISA. Hence, the unstable antibody dynamics in ELISA may pose a challenge for serological surveys of T. gondii in sows.

Association between latent toxoplasmosis and fertility parameters of men

BACKGROUND

About a third of people in the world are infected with Toxoplasma gondii. This parasite has been found in the reproductive organs and semen of males of many animal species as well as humans. The effects of toxoplasmosis on sperm count, motility and morphology were confirmed in rats. A higher prevalence of toxoplasmosis has been observed in infertile men. On the other hand, no significant effect of infection on semen parameters in men was found in one already published study.

OBJECTIVES

To compare the prevalence of toxoplasmosis in men with and without semen pathology and to examine in detail the possible impact of infection on semen volume, sperm count, motility and morphology.

MATERIALS AND METHODS

The pre-registered cross-sectional study included 669 men who visited the Centre for Assisted Reproduction in Prague from June 2016 until June 2018.

RESULTS

The incidence of fertility problems was significantly higher in the 163 Toxoplasma-infected men (48.47%) than in the 506 Toxoplasma-free men (42.29%), τ = 0.049, P = 0.029. After correction for multiple tests, we found significantly lower sperm concentration, concentration of progressively motile sperm, and concentration of non-progressively motile sperm in Toxoplasma-positive men than in Toxoplasma-negative men using partial Kendall correlation with age controlled. In addition, toxoplasmosis correlated with sperm quality in smokers but not in non-smokers.

DISCUSSION AND CONCLUSION

Our results suggest that latent toxoplasmosis affects certain semen parameters (sperm count and motility), but does not seem to affect sperm morphology and semen volume. Impairment of semen parameters may be either a side effect of the presence of Toxoplasma gondii in male reproductive organs or a product of manipulation activity of the parasite aimed to increase the efficiency of the sexual route of its transmission. Tobacco smoking also appears to exacerbate the negative impact of toxoplasmosis on semen parameters.

Male-to-Female Presumed Transmission of Toxoplasmosis Between Sexual Partners

Toxoplasmosis is one of the most widespread human parasitoses in developed countries. Sexual transmission has been confirmed in several animal species, and indirect evidence suggests it may occur in humans. We compared the seropositivity to Toxoplasma gondii in couples who visited the Center for Assisted Reproduction in Prague from June 2016 to June 2018 and analyzed various risk factors including the serological status of sexual partner. By comparing the risk factors in men and women, we tested the hypothesis of male-to-female sexual transmission of toxoplasmosis. The prevalence of toxoplasmosis in women with infected male partners (25.6%; n = 156) was higher than in women with uninfected male partners (18.2%; n = 477; P = 0.045). Therefore, a partner's seropositivity seems to be a risk factor for infection in women (n = 593; prevalence ratio = 1.418; P = 0.045) but not in men (n = 573; prevalence ratio = 1.058; P = 0.816). Our results support the hypothesis of the sexual transmission of T. gondii from men to women. The risk may seem relatively low, but transmission can occur during unprotected sexual intercourse, which may be at the time of conception. Because of the risk of congenital toxoplasmosis, a lower risk of infection than that observed in our study can represent a serious health problem.

Effect of Toxoplasma gondii on Ram Sperm Quality After Experimental Infection

The aim of this study was to investigate the effect of experimental Toxoplasma gondii infection on ram sperm quality. Five months old, pre-pubertal, rams were divided into four groups (n = 8 per group). Group A was the control group; the remaining animals received per os (p.o.) 5000 oocysts per ram. Group B did not receive treatment post-infection (p.i.). Group C received sulphadimidine (intermuscular injection (i.m.) 33 mg/kg for eight days; every 48 hrs) two months p.i. and Group D received the same drug twice (24 hours p.i. and two months later). Blood samples were collected every 15 days to detect serum immunoglobulin G (IgG). Epididymal sperm samples were analyzed for concentration, kinetics, morphology/viability, functional membrane integrity, DNA integrity, and the presence of parasite DNA. Histopathological examination was performed on the testes. The IgG titres in infected groups raised two weeks p.i. and remained high for four months. Higher values were noticed in viability and functional membrane integrity in positive spermatozoa in the control group compared to other groups, level of significance p < 0.05. Abnormal sperm was higher in groups C and D vs. A and C vs. B (p < 0.05). T. gondii DNA was detected in three sperm samples of the infected rams (12.5%). Histopathology revealed similar findings with little variation among all infected groups, characterized mostly by increased interstitial connective tissue, non-purulent inflammation, and presence of seminiferous tubules with spermatogenic cell depletion, which increased gradually from D to C and B groups. In conclusion Toxoplasmosis in pre-pubertal age negatively affected mature ram sperm quality, while sulphadimidine administration failed to alter this.

Detection of Toxoplasma gondii infection in semen of rams used for natural mating in commercial sheep farms in Tunisia

Toxoplasmosis, a parasitic infection, disrupts sexual functions resulting in decline in reproductive and economic performance in sheep. Lacking discernible symptoms, toxoplasmosis is difficult to detect and diagnose in infected animals. Here, to estimate the prevalence of natural infection by Toxoplasma gondii, we used PCR to amplify and detect T. gondii DNA in semen from 92 rams of three breeds from four regions in Tunisia and seroprevalence was determined using a commercial ELISA kit. From the PCR amplifications, 51.09 ± 10.21% of the rams were tested positive for T. gondii with an overall seroprevalence of 39.13 ± 9.97%. Risk factors including ram location and number of accomplished mating seasons significantly (p < .05) affected the sero- and molecular prevalence of T. gondii in semen but, there was a fair concordance between sero- and molecular prevalence (Kappa = 0.33). Sequences of T. gondii from five positive samples were 100% identical (same haplotype). Comparison of these sequences with those archived at the GenBank showed a sequence similarity range between 95 and 100%. The haplotype defining the five Tunisian sequences was similar to the one observed in chicken, cats, European pole cat and humans from Brazil, St Kitts and Nevis, Great Britain and Tunisia, respectively. This indicates its wide geographic distribution and non-species specificity. Our findings suggest a high prevalence of toxoplasmosis in Tunisian matting rams; further studies concerning its venereal transmission capacity are needed prior to recommending a systematic screening of T. gondii DNA in rams' semen used for both natural breeding and artificial insemination.

Toxoplasma gondii in milk of naturally infected dairy ewes on west mesoregion of Santa Catarina state, Brazil

ABSTRACT This study aimed to detect Toxoplasma gondii in the milk of dairy sheep in the Western mesorregion of state of Santa Catarina by bioassay (22 milk samples from eight ewes seropositive; IFA ≥256) and PCR [for the detection of agent in the brains of mice inoculated on bioassay and directly from milk (108 samples from 42 seropositive ewes (IFA, ≥64) in different lactation periods)]. T. gondii DNA was detected in mice brains inoculated with milk from eight sheep (a sample of the 45th day of lactation and seven in the collection of 90th day) and directly from the milk in samples of the second collection (90 days) in five animals. Taking into account both assays, from a total of 42 ewes in lactation and seropositive for T. gondii, 30.95% (13/42) of the animals presented evidences of T. gondii presence in milk. Positive PCR samples were sequenced and the results confirmed ≥97% identity with the membrane antigen P22 gene of T. gondii. The results showed that T. gondii is present in the milk of sheep, representing a possible source of infection to humans through the consumption of milk "in natura" and/or derivatives, besides the possibility of lactogenic transmission to lambs.

Investigation of Toxoplasma gondii in semen, testicle and epididymis tissues of primo-infected cats (Felis catus)

This study aimed to investigate the presence of Toxoplasma gondii in semen, testicle and epididymis tissues of cats experimentally infected by this coccidium. A total of 12 male felines without a definite breed that were of reproductive age and serologically negative for T. gondii were selected and distributed to the following three experimental groups: GI, inoculated with 600 tissue cysts of the P strain of T. gondii (isolate III); GII, inoculated with 2×10⁵ tachyzoites of the RH strain (isolate I); and GIII, not inoculated (control group). Prior to inoculation (day -7 and 0) and on post inoculation days (PIDs) 7, 14, 21, 28, 42, 56, and 70, all felines were subjected to assessments of anti-T. gondii IgG by indirect immunofluorescence (IIF) and assessments of parasitemia. Collection of semen (electroejaculation) was performed on the specified dates, followed by nested PCR and bioassays in mice to detect T. gondii. On PID 70, all 12 felines were orchiectomized, and the presence of the parasite in the testicles and epididymides was evaluated by nested PCR, murine bioassay, and histopathological and immunohistochemical analyses. All felines inoculated with T. gondii (GI and GII) seroconverted to the toxoplasmic infection after PID 14; on PID 7, seroconversion of three felines (P4, RH2 and RH4) could observed, and all exhibited detectable titers by PID 64. The GII felines exhibited greater serological titers compared with GI felines. The maximum serological titer (IgG) was observed in feline RH3 (titer 1024), while in other experimental felines, a maximum titer of 256 was detected. Parasitemic peaks were diagnosed in all felines of groups I and II from PIDs 7-42. A total of five parasitemic peaks were diagnosed in GI and nine in GII. In none of the experimental time points was the presence of T. gondii diagnosed in seminal samples collected from the felines or in the testicle or epididymis tissues collected from these animals. Thus, sexual transmission in domestic cats does not appear to be a major route of T. gondii infection, possibly demonstrating the tendency of this protozoan to develop a response directed to the formation and excretion of oocysts in the feces of these definite hosts, which act as its main route of perpetuation in the environment.

Vertical transmission of Trypanosoma evansi in experimentally infected rats

Many reproductive problems has been described in male and female animals infected by Trypanosoma evansi. Thus, the aim of this study was to evaluate the occurrence of vertical (Experiment I) and venereal (Experiment II) transmission of T. evansi in rats experimentally infected. In the experiment I, eight female Wistar rats were used: three animals as negative controls, and five rats were infected by T. evansi on day ten of gestation. Out of these eight females, half puppies were used for molecular analysis (polymerase chain reaction - PCR) for T. evansi. Two infected females showed delivery problems, such as stillbirth, and fetal death that also led to female death. Three female rats infected had normal delivery of stunted offspring at term that died 2 days after birth. Rats from the control group had normal delivery of healthy offspring. T. evansi PCR was positive for 80% (12/15) of pups in the infected group. For the experiment II, five male rats were infected by T. evansi, and monitored by blood smears to check the parasitemia level. When the male rats showed parasitemia between 2 and 5 parasites per field, they were individually housed with one female adult rat. After approximately 21 days, the females delivered their offspring. Blood sample was collected from the females for blood smears and T. evansi PCR tests, which revealed negative results. Therefore, we were able to prove the occurrence of transplacental transmission of T. evansi and its negative effect on female rats and their offspring.

Congenital Toxoplasmosis in Chronically Infected and Subsequently Challenged Ewes

This experiment studied congenital transmission in sheep experimentally infected with oocysts of Toxoplasma gondii and reinfected at one of three stages of pregnancy. Twenty ewes were experimentally infected with T. gondii strain ME49 (day 0). After the T. gondii infection became chronic (IFAT≤512), the ewes were allocated with rams for coverage. After the diagnosis of pregnancy, these ewes were allocated into four experimental groups (n = 5): I-reinfected with T. gondii on the 40^th day of gestation (DG); II-reinfected on DG 80; III-reinfected on DG 120; and IV-saline solution on DG 120 (not reinfected). Five ewes (IFAT<64) were kept as negative controls (uninfected, group V), therefore in groups I-III were infected prior to pregnancy and re-infected during pregnancy, group IV was only infected prior to pregnancy, and group V was not infected. Parasitism by T. gondii was investigated (histopathology, immunohistochemistry, mouse bioassay and PCR) in mothers and lambs tissue. All ewes produced lambs serologically positive for T. gondii. The results of the mouse bioassay, immunohistochemistry and PCR assays revealed the presence of T. gondii in all 20 sheep and their lambs. The congenital transmission of T. gondii was associated with fetal loss and abnormalities in persistently infected sheep and in ewes infected and subsequently reinfected by this protozoan. Therefore, congenital T. gondii infection was common when ewes were chronically infected prior to pregnancy, with or without reinfection during at various stages of gestation.

Experimental infection with the Toxoplasma gondii ME-49 strain in the Brazilian BR-1 mini pig is a suitable animal model for human toxoplasmosis

Toxoplasma gondii causes toxoplasmosis, a worldwide disease. Experimentation with pigs is necessary for the development of new therapeutic approaches to human diseases. BR-1 mini pigs were intramuscularly infected with T. gondii with tachyzoites (RH strain) or orally infected with cysts (ME-49 strain). Haematology and serum biochemistry were analysed and buffy coat cells were inoculated in mice to determine tachyzoite circulation. No alterations were observed in erythrocyte and platelet values; however, band neutrophils increased seven days after infection with ME-49. Serology of the mice inoculated with pig blood leucocytes revealed circulating ME-49 or RH strain tachyzoites in the pigs' peripheral blood at two and seven or nine days post-infection. The tachyzoites were also directly observed in blood smears from the infected pigs outside and inside leucocytes for longer periods. Alanine-aminotransferase was high at days 21 and 32 in the RH infected pigs. After 90 days, the pigs were euthanised and their tissue samples were processed and inoculated into mice. The mice serology revealed the presence of parasites in the hearts, ileums and mesenteric lymph nodes of the pigs. Additionally, cysts in the mice were only observed after pig heart tissue inoculation. The infected pigs presented similar human outcomes with relatively low pathogenicity and the BR-1 mini pig model infected with ME-49 is suitable to monitor experimental toxoplasmosis.

Toxoplasma gondii and Neospora caninum in slaughtered pigs from Northeast, Brazil

The aims of this study were to evaluate the presence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies, to identify associated risk factors and to isolate T. gondii from slaughtered pigs in Paraíba State, Brazil. A total of 190 pigs from public slaughterhouses were used in the study. An indirect immunofluorescence test was used to detect antibodies, and the isolation of T. gondii was performed with a bioassay in mice based on tissues from seropositive animals. A total of 50 g of brain, heart and tongue tissue from 37 positive pigs with titres ≥ 1:64 was ground, digested with acidic pepsin and inoculated into mice. The prevalence of anti-T. gondii antibodies was 19.5% (95% CI: 14.1%; 25.8%) (37/190), with titres ranging from 1:64 to 1:2048. Viable T. gondii parasites were isolated from 13 of the 37 (35.1%; 95% CI: 20.2%; 52.5%) seropositive pigs. We found that the virulence of the isolates varied; three of these isolates were able to kill all of the inoculated mice. The risk factors for infection were extensive husbandry and feeding with leftovers. The prevalence of antibodies to N. caninum in pigs was 3.2% (95% CI: 1.2%; 6.7%) (6/190), with titres ranging from 1:100 to 1:3200. None of the variables studied were considered to be risk factors for N. caninum. These results show that the prevalence of anti-T. gondii antibodies in swine is high in Paraíba State, that the percentage of viable T. gondii parasites recovered from these animals is also high and that infection by this parasite is closely related to the management of swine. Despite the low prevalence of N. caninum in pigs, further studies are necessary to determine the importance of this parasite for the species.

Toll-like receptor 11-initiated innate immune response in male mouse germ cells

Toxoplasma gondii and uropathogenic Escherichia coli (UPEC) may infect the testis and impair testicular function. Mechanisms underlying testicular innate immune response to these two pathogens remain to be clarified. The present study examined the function of TLR11, which can be recognized by T. gondii-derived profilin and UPEC, in initiating innate immune response in male mouse germ cells. TLR11 is predominantly expressed in spermatids. Profilin and UPEC induced the expressions of different inflammatory cytokine profiles in the germ cells. In particular, profilin induced the expressions of macrophage chemotactic protein 1 (MCP1), interleukin 12 (IL12), and interferon gamma (IFNG) through nuclear factor KB (NFKB) activation. UPEC induced the expressions of MCP1, IL12, and IFNG, as well as tumor necrosis factor alpha (TNFA), IL6, and IFNB, through the activation of NFKB, IFN regulatory factor 3, and mitogen-activated protein kinases. Evidence showed that profilin induced the innate response in male germ cells through TLR11 signaling, and UPEC triggered the response through TLR11 and other TLR-signaling pathways. We also provided evidence that local injection of profilin or UPEC induces the innate immune response in the germ cells. Data describe TLR11-mediated innate immune function of male germ cells in response to T. gondii profilin and UPEC stimulations. This system may play a role in testicular defense against T. gondii and UPEC infections in mice.

Experimental vaginal infection of goats with semen contaminated with the "CPG" strain of Toxoplasma gondii

The objective was to characterize the transmission of Toxoplasma gondii in goats experimentally infected vaginally with semen contaminated with the CPG strain (genotype III). Ten female goats were randomly allocated into 2 groups (G1 and G2), each with 5 animals, and inseminated during estrus. Goats in G1 were inseminated with semen containing 1 × 10(5) tachyzoites, whereas those in G2 (control) were inseminated with semen free from tachyzoites (insemination = day 0). In G1, seroconversion (indirect immunofluorescence reaction) and DNA (polymerase chain reaction) in the blood was present in 4/5 and 3/5, respectively, from the 7th day. In G2, all goats were negative in all tests. Embryonic reabsorption occurred in 4 of 5 goats from G1 between days 21 and 49. In conclusion, artificial vaginal insemination with semen containing tachyzoites of T. gondii -infected goats and is a potential transmission route of this parasite through semen.

Neto OLD, Guerra MMP. Prevalência e fatores de risco associados à infecção por Toxoplasma gondii em granjas suinícolas tecnificadas no Estado de Alagoas

Objetivou-se com este estudo calcular a prevalência e identificar os fatores de risco associados à infecção por Toxoplasma gondii em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Para compor a amostra do estudo de prevalência foram utilizados 342 suínos, sendo 312 matrizes e 30 varrões, oriundos de sete granjas de ciclo completo e distribuídas em cinco municípios do Estado de Alagoas. O exame sorológico para a pesquisa de anticorpos anti-Toxoplasma gondii foi realizado através da técnica de Imunofluorescência Indireta (RIFI), utilizando-se anticorpos anti-IgG-suíno conjugado ao isotiocianato de fluoresceína. A análise dos fatores de risco foi realizada por meio da aplicação de questionários constituídos por perguntas objetivas referentes ao criador, às características gerais da propriedade, ao manejo produtivo, reprodutivo e sanitário. Determinou-se uma prevalência de 26,9% (92/342) de suínos soropositivos. O fator associado à infecção foi a introdução de reprodutores nas granjas nos últimos cinco anos (p=0,014; OR=1,83; IC=1,13-2,96). Concluiu-se que a infecção por Toxoplasma gondii encontra-se disseminada em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Recomenda-se o controle da população de gatos, a realização de práticas de limpeza e higienização das instalações e realização de testes laboratoriais para diagnóstico da infecção por T. gondii nos animais a serem introduzidos no plantel como medidas de redução dos índices de infecção na região estudada.

Histopathology of the reproductive system of male sheep experimentally infected with Toxoplasma gondii

The aim of this study was to investigate the histopathological changes in reproductive system (testicles, epididymis, seminal vesicles, and prostate) of small male ruminants after Toxoplasma gondii infection. Eight sheep were inoculated with T. gondii: group I, four sheep (2.0 × 10(5) P-strain oocysts); group II, four sheep (1.0 × 10(6) RH-strain tachyzoites); and group III, two uninfected sheep maintained as control. Infection with T. gondii was confirmed by seroconversion (indirect fluorescent antibody test-IgG) in all the infected animals beginning on post-inoculation day (PID) 7. On PID 70, all the animals were euthanized and tissue samples (testicles, epididymis, seminal vesicles, and prostate) were collected and processed for histological analysis. The main changes detected were a focal mononuclear interstitial inflammatory infiltrate in the prostate and seminal vesicles; diffuse testicular degeneration associated with calcification foci and a multifocal mononuclear interstitial inflammatory infiltrate; and a mononuclear interstitial infiltrate and focal necrotic areas of the muscle fibers surrounding the seminal vesicles. The histopathological findings of this work, along with the detection of T. gondii in the examined parenchyma tissues (immunohistochemistry) and the results obtained by other authors examining different tissues, suggest that histological changes diagnosed in the reproductive system of rams infected with T. gondii are strongly suggestive of toxoplasmatic infection.

Detecção de Toxoplasma gondii no sêmen de ovinos naturalmente infectados

O objetivo deste trabalho foi estudar a eliminação de Toxoplasma gondii no sêmen de carneiros naturalmente infectados. Foram utilizados 65 reprodutores submetidos inicialmente à pesquisa de anticorpos anti-T. gondii por meio da técnica de imunofluorescência indireta (IFI). Os carneiros sorologicamente positivos foram submetidos à colheita de sêmen para detecção do DNA de T. gondii. Na sorologia observaram-se 6/65 (9,2%) carneiros positivos, enquanto no PCR nested de sêmen 4/6 (66,6%) carneiros foram positivos. Conclui-se que a detecção, por meio da técnica da PCR nested, da forma proliferativa de T. gondii no sêmen de carneiros naturalmente infectados, reforça a necessidade de se pesquisar sobre a possibilidade da transmissão horizontal do parasito via sêmen na espécie ovina.

Aspects of toxoplasma infection on the reproductive system of experimentally infected rams (ovis aries)

Eight reproductive rams with no prior reproductive disease were distributed into three groups of infection with T. gondii: GI, 3 rams, 2.0 × 10⁵ P strain oocysts; GII, 3 rams, 1.0 × 10⁶ RH strain tachyzoites; GIII, 2 control rams. Clinical parameters were measured and serological evaluations (IIF) were performed. Presence of the parasite in the semen was investigated by PCR and bioassay techniques. The rams presented clinical alterations (hyperthermia and apathy) related to toxoplasmosis in both groups infected with Toxoplasma gondii. All the inoculated rams responded to antigenic stimulus, producing antibodies against T. gondii from postinoculation day 5 onwards. In ovine groups I and II, the greatest titers observed were 1 : 4096 and 1 : 8192, respectively. In semen samples collected from these two groups, the presence of T. gondii was detected by bioassay and PCR. This coccidian was isolated (bioassay and PCR) in tissue pools (testicles, epididymis, seminal vesicle, and prostrate) from two rams infected presenting oocysts and in one presenting tachyzoites.

Toxoplasma gondii in experimentally infected Bos taurus and Bos indicus semen and tissues

Eighteen young steers were inoculated with Toxoplasma gondii and randomly distributed into three groups of six animals each: GI, 2.5x10(5) "P" strain oocysts, GII, 5.0x10(6) "RH" strain tachyzoites, and GIII (Control). Clinical, serological and parasitemia exams were realized. Parasite investigation by bioassay and PCR was realized on semen and fragments of skeletal musculature, lymph nodes, brain, retina, spleen, liver, lung, testicle, epididymis and seminal vesicle. Blood and semen samples were collected on days -2, -1, 1, 3, 5, 7, 14 and weekly thereafter, up to postinfection day (PID) 84. The inoculated steers (GI and GII) presented hyperthermia from PID 3 to 16. Antibodies against T. gondii were detected through the indirect fluorescence antibody test (IFAT) on PID 5 (1:16) in both inoculated groups (oocysts and tachyzoites), reaching peaks of 1:4096 on PID 7. Parasitemia outbursts occurred in all infected bovines, principally from PID 7 to 28, independent of the strain and inoculate used. Bioassays revealed the presence of parasites in semen samples of animals infected with oocysts (GI) and tachyzoites (GII) on several experimental days between PID 7 and 84. Tissue parasitism by T. gondii was diagnosed by bioassay and the PCR technique in several organ and tissue fragments. These findings suggest the possibility of sexual transmission of T. gondii in the bovine species.

Toxoplasma gondii: reproductive parameters in experimentally infected male rats

Toxoplasma gondii is a protozoan parasite that is globally widespread and infects man and animals. With the aim of studying the influence of toxoplasmosis on male reproductive parameters, we investigated sperm motility, concentration and morphology of male rats experimentally infected by T. gondii. The GT F1 strain of T. gondii tissue cysts were fed at a dose of 5 x 10(3) tissue cysts per rat by oral gavage in an experimental group of 42 healthy adult male Wistar rats, while 42 male rats were used as controls. On days 10, 20, 30, 40, 50 and 60 post-inoculation (p.i.) 7 rats from each group were anesthetized. The body weight of each animal was recorded, then epididymis and testes were immediately removed, weighed and semen evaluation was undertaken. Weight of the right epididymis was significantly decreased on day 30 p.i., sperm motility was significantly decreased on days 10, 20, 30, 40, 50 and 60 p.i. and sperm concentration was significantly decreased on days 10, 30, 40 and 60 p.i. A marked increase of sperm abnormalities was noticed on days 30 and 40 p.i. No pathological lesions were detected either in the pituitary gland or the testes. In this study it was found that toxoplasmosis can affect main reproductive parameters in male rats, which are the most predictive of their fertilizing capacity.