ArticlePDF Available

The association of latent toxoplasmosis and level of serum testosterone in humans



Objectives: Latent toxoplasmosis modifies various hormones and behaviors in infected hosts and possibly involves in etiology of different neurologic and psychiatric disorders. The aim of the current study was to assess possible associations between latent toxoplasmosis and testosterone concentration in Toxoplasma infected and free subjects. Briefly, 18-49 year-old participated in the study. After collected blood samples, sera were analyzed for the detection of anti-Toxoplasma IgG antibody. Totally, 76 positive sera were selected as study group (38 from men and 38 from women) and a same number of negative sera as control group. Results: Comparison of testosterone concentrations and control groups showed that testosterone concentration in study group was higher than that in control group with statistically significant difference (P = 0.024 and P = 0.043 for men and women, respectively). Significant differences were found in testosterone concentrations and anti-Toxoplasma IgG antibody levels in study and control groups (P < 0.05). Toxoplasmosis can affect the mean concentration of serum testosterone in human. Alteration of testosterone during latent toxoplasmosis can result in alterations in behavioral, physiologic and immunological parameters in long time.
Zoueietal. BMC Res Notes (2018) 11:365
The association oflatent toxoplasmosis
andlevel ofserum testosterone inhumans
Nima Zouei, Saeedeh Shojaee, Mehdi Mohebali and Hossein Keshavarz*
Objectives: Latent toxoplasmosis modifies various hormones and behaviors in infected hosts and possibly involves
in etiology of different neurologic and psychiatric disorders. The aim of the current study was to assess possible
associations between latent toxoplasmosis and testosterone concentration in Toxoplasma infected and free subjects.
Briefly, 18–49 year-old participated in the study. After collected blood samples, sera were analyzed for the detection
of anti-Toxoplasma IgG antibody. Totally, 76 positive sera were selected as study group (38 from men and 38 from
women) and a same number of negative sera as control group.
Results: Comparison of testosterone concentrations and control groups showed that testosterone concentration
in study group was higher than that in control group with statistically significant difference (P = 0.024 and P = 0.043
for men and women, respectively). Significant differences were found in testosterone concentrations and anti-Toxo-
plasma IgG antibody levels in study and control groups (P < 0.05). Toxoplasmosis can affect the mean concentration
of serum testosterone in human. Alteration of testosterone during latent toxoplasmosis can result in alterations in
behavioral, physiologic and immunological parameters in long time.
Keywords: Toxoplasma gondii, Testosterone, Electro chemiluminescence immunoassay, Latent toxoplasmosis
© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License
(http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,
provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creat iveco mmons .org/
publi cdoma in/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Toxoplasma gondii is one of the most common parasitic
protozoans in humans which cause toxoplasmosis [1].
e prevalence of toxoplasmosis varies from 20 to 80%
in different parts of the world. Humans become infected
through the oral route by the consumption of raw or
undercooked meat contaminated with tissue cysts and
other food products, water or vegetables contaminated
with oocysts. Congenital infection can occur via verti-
cal transmission of T. gondii tachyzoites from pregnant
mother to developing fetus during the primary infection
that could be life threatening for the fetus [2]. erefore,
the accurate diagnosis of acute maternal toxoplasmosis
in pregnant women is critical [3]. Latent toxoplasmosis
is clinically asymptomatic in immunocompetent hosts.
However, the infection is usually long-lasting character-
ized by the presence of Toxoplasma cysts, typically in
nervous and muscular tissues. Furthermore, the infection
mostly results in a lifetime protective immunity (humoral
and cellular) to reinfection, presenting low levels of anti-
Toxoplasma IgG in serum of infected individuals [4].
Latent toxoplasmosis is known to induce various hor-
monal and behavioral changes in infected humans and
animals and may be involved in etiology of different neu-
rologic and psychiatric disorders [57]. Infected mice
and rats have been shown to suffer from impaired motor
neuron performance and coordination, deficit learning
and reduced avoidance of open spaces and predators
[812]. ese are believed to be evolutionary mecha-
nisms to increase the chance of hosts being eaten by
felines [13]. Furthermore, latent toxoplasmosis increases
chance of giving birth to males in humans and mice [14,
15]. Patients with changed testosterone levels may expe-
rience physical symptoms such as dermal hyper reactions
including irritation, erythema, hirsutism and acne as well
as abnormal growth of muscles, kidney failure and psy-
chological deficits such as mood swings, depression and
anxiety [16]. An effect of latent toxoplasmosis on serum
testosterone changes is still being discussed by research-
ers. Published data have shown increased and decreased
testosterone levels associated with T. gondii seropositivity
Open Access
BMC Research Notes
Department of Medical Parasitology and Mycology, Tehran
University of Medical Sciences, Pour Sina St., Ghods St., Enghelab St.,
Tehran 1417613191, Iran
Page 2 of 5
Zoueietal. BMC Res Notes (2018) 11:365
in humans [1719]. In the current study, effects of latent
toxoplasmosis on serum testosterone were assessed in
men and women.
Main text
Samples andpatients
In this case–control study, 18–49 year-old men and
women with no clinical complications were participated.
Blood samples were collected in clinical laboratories in
Tehran, May–September 2013. Information sheets were
prepared and demographic questionnaires completed
for the participants. en, 3 ml of whole blood were
collected and sera were tested for the detection of anti-
Toxoplasma IgG antibody. In total, 76 positive sera were
selected as study group (equally from men and women)
and further 76 negative as control group.
Serological tests
Enzyme-linked immunosorbent assay (ELISA) was used
to detection of anti-Toxoplasma IgG antibody in blood
sera. e cut off values of optical densities (OD) were
calculated according to a protocol by Hillyer etal. [20].
e OD of each sample was compared with cut off and
Antigen preparation
Antigen was prepared as previously described [21]. e
RH strain of T. gondii was obtained from the Depart-
ment of Parasitology, Tehran University of Medical Sci-
ences, Tehran, Iran. Briefly, tachyzoites of T. gondii, RH
strain were inoculated intraperitoneally into BALB/c
mice. After 48–72 h, tachyzoites were collected using
peritoneum washing with sterile normal saline (pH 7.2).
Tachyzoites were washed with phosphate-buffered saline
(PBS pH 7.4) for three times, sonicated in PBS (pH 7.4)
and centrifuged at 12,000g for 1h at 4°C. en, super-
natants were collected and protein density was assessed
using Bradford method. Animal experiments were done
according to Committee for the Update of the Guide for
the Care and Use of Laboratory Animals and approved by
the Ethical Committee of Tehran University of Medical
Sciences for the use of laboratory animals.
Detection ofanti‑Toxoplasma IgG antibody using ELISA
e 96-well microplates (Nunk, Germany) were coated
with 5 µg/ml of soluble antigen of T. gondii RH strain
in carbonate-bicarbonate buffer (pH 9.6) and stored at
4°C. Plates were washed for three times with PBST (PBS,
0.05% tween 20) and sera were diluted 1:200 in PBST and
100µl from diluted sera was added to each well of micro-
plate. After incubation for 1h at 37°C and three times
of washing, 100 µl of anti-human IgG conjugated with
hourseradish peroxidase (HRP) (Dako, Denmark) diluted
1:500 in PBST and added to each well. After incubating
and washing, 100 µl of substrate of ortho-phenylenedi-
amine (OPD) (Sigma-Aldrich, USA) was added to wells.
e catalytic enzyme was stopped by adding 50 µl of
20% sulfuric acid at a specific time and the absorbance
was measured at 490nm using automated ELISA reader
(BIOTEC LX800, USA). Furthermore, all samples were
approved for the determination of anti-Toxoplasma IgG
using commercial kits (Trinity Biotech Captia, New York,
USA) according to the manufacturer’s instructions.
Testosterone assessment
Concentration of testosterone was assessed at 37°C using
Roche Cobas® e 411 Immunoassay (Roche Diagnostics,
Mannheim, Germany) according to the manufacturer’s
instructions. In the first incubation step, 20 μl of the
sample were incubated with a biotinylated monoclonal
testosterone-specific antibody and 2-bromoestradiol (to
release testosterone). In the second step, streptavidin-
coated microparticles and a ruthenylated testosterone
derivative were added to the mixture. e reaction mix-
ture was transferred to a measuring cell and the micro-
particles were magnetically captured on the surface of an
electrode. Chemiluminescence was measured using pho-
tomultiplier and the concentration of testosterone was
calculated using calibration curve [22]. Interpretation of
the testosterone concentration was based on the manu-
facturer’s recommendation as follows: normal range for
men, 2.49–8.36ng/ml; and for women, 0.084–0.481ng/
ml. Experiments were carried out in triplicate, and the
mean was calculated for each sample.
Statistical analysis
Statistical analyses were carried out using SPSS Software
v.16. Data were analyzed using multiple univariate analy-
ses of variance (ANOVA) and Chi square test. Pearson
product-moment correlations were used between opti-
cal density of ELISA and concentration of testosterone.
Comparison of quantitative variants between two groups
was assessed by student t test. Data description was car-
ried out by calculating frequencies and 95% confidence
intervals. Differences were considered as significant
when P 0.05.
Results of anti-Toxoplasma IgG antibody detection
and serum testosterone concentration in infected and
non-infected subjects are shown in Table1. Differences
in mean concentrations of testosterone were reported
between infected and non-infected subjects (P < 0.05)
as testosterone concentration was significantly higher
Page 3 of 5
Zoueietal. BMC Res Notes (2018) 11:365
in IgG-positive group than that in IgG-negative one. In
infected subjects, 13.2 and 26.3% of men and women
had high concentrations of serum testosterone, respec-
tively. e mean concentration of serum testosterone was
higher in men and women infected by T. gondii and sta-
tistically significant (P = 0.02 and P = 0.04, resp ectively),
compared to that in control group. Furthermore, corre-
lation between the mean OD of ELISA and concentra-
tion of testosterone was significant in infected men and
women with values of 0.007 and 0.004, respectively. No
statistically significant association was found between
IgG titers and testosterone levels in men and women in
Toxoplasma seropositivity group in comparison with
control group (P > 0.05).
Parasite-induced changes to the host endocrine system
provide a possible mechanism of altering host behav-
iors. Significant sex differences have been reported
regarding host changes in response to T. gondii infec-
tion [19]. Testosterone is an important influencing fac-
tor in behavior and personality in both sexes. As shown
in majority of the studies, increased testosterone was
associated with antisocial, aggression and dominance
behaviors [2325]. Altered testosterone levels have been
observed in T. gondii infections; however the literatures
lack consensuses. Evidence suggests that testosterone
activation may cause sexual arousal directed towards
feline odor in some rodents [26]. Interestingly, castrated
male rats do not exhibit loss of fear phenotype, suggest-
ing that testosterone plays a direct role in this behavior
[27]. Results of the current study have shown that mean
concentrations of serum testosterone are significantly
higher in men and women infected by toxoplasmosis,
compared to that in control group. Increased concen-
tration of testosterone during latent toxoplasmosis can
result in inducted behavioral alterations and immuno-
suppressive effects characterized by lower cellular immu-
nity [25, 28]. Administration of exogenous testosterone
can reduce fear in humans and rodents [29]. It is possi-
ble that men with increased levels of testosterone have
greater chance of Toxoplasma infection either due to
impaired immunity or changed behavior and personality
profile. For instance, personal tendency to disregard rules
of the society can result in lower hygienic standards and
hence increase risk of contact with sources of infection
[3033]. e underlying mechanism for these behavioral
alterations are usually thought to be variations in neuro-
transmitter functions and more specifically due to high
levels of dopamine. In addition, there are indications that
enhanced testosterone levels play an important role in
behavioral abnormalities [34].
Several studies have shown that, direct and indirect
evidence exist on increased testosterone in Toxoplasma
infected human and animals [3539]. T. gondii produces
high concentrations of testosterone in infected hosts
and enhanced mRNA expression of luteinizing hormone
receptor (LHR), which regulate the synthesis of testos-
terone in testes on Leydig cells [27]. e Toxoplasma
infected men are about 3cm taller than Toxoplasma free
men and having further muscles and dominant faces [38,
39]. Toxoplasma infected men and women have a lower
second to fourth digit length ratio in the left hand (2D:4D
ratio) and are more likely to give birth to boys than
girls [14, 40]. e findings of current study is in accord-
ance with James hypothesis (2010) that many parasites
and pathogens could change the concentration of ster-
oid hormone. He has demonstrated that infected hosts,
often with shifted sex ratio, increase number of males
in generations [40]. Testosterone is a hormone which
is responsible for the growth of secondary male sexual
characteristics. An alternative hypothesis explaining Tox-
oplasma associated sex ratio shift suggests that the phe-
nomenon is caused by the higher possibility of survival of
more immunogenic male embryos by inducing immuno-
suppression mechanisms [30]. Indeed, both hypotheses
may be compatible since the proximate mechanism of
immunosuppression remains unknown and may involve
the parasite-induced shift in steroid hormones.
e results of present study do not agree with Flegr
etal. showed that Toxoplasma infected men had a higher
concentration of testosterone while women had a lower
concentration of the hormone, compared to control
group [19]. Furthermore, Flegr suggested that the per-
sonality profiles of infected men and women are differ-
ent and the opposite direction of the testosterone shift in
men compared to women can explain the observed gen-
der specificity of behavioral changes in people infected
with Toxoplasma parasite. ey have concluded that
infected women are warm-hearted, conscientious, out-
going, persistent, and moralistic while infected men are
Table 1 Mean OD of ELISA and concentration
of testosterone (ng/ml) in 18–49 year-old infected men
andwomen, compared tothatin non-infected ones
Group Mean OD ± SD Mean concentration
oftestosterone (ng/
ml) ± SD
Infected men 1.05 ± 0.53 5.6 ± 1.99
Infected women 0.94 ± 0.37 0.41 ± 0.22
Non-infected men (sero-
negative) 0.14 ± 0.08 4.56 ± 1.96
Non-infected women
(sero-negative) 0.15 ± 0.08 0.31 ± 0.17
Page 4 of 5
Zoueietal. BMC Res Notes (2018) 11:365
more likely to disregard rules and were more expedient,
suspicious, jealous, and dogmatic [19].
Contrary to our results, a controversial study by Kank-
ova etal. has shown a decrease testosterone levels (total
testosterone and free testosterone) in female and male
laboratory mice infected by virulent strains of Toxo-
plasma at a latent phase, compared to uninfected con-
trols. is controversy may be seen due to the different
parasite strain, which differs in virulence and epidemio-
logical occurrence [41]. erefore, the parasite genotype
seems to be an important parameter influencing the clin-
ical infection in humans [42]. It is possible that the physi-
ological reaction to Toxoplasma infection qualitatively
differs between mice and humans. Other reports show
that reduced serum and testicular testosterone levels was
found in male rats infected by high doses of T. gondii, RH
strain compared to controls [43]. Similarly, Oktenli etal.
have demonstrated that concentration of follicle stimu-
lating hormone (FSH), luteinizing hormone (LH), free
testosterone (FT) and total testosterone(TT) were sig-
nificantly lower than controls in serum of male patients
during acute toxoplasmosis [44]. Results of the current
study showed that the mean concentration of serum
testosterone was higher in men and women infected by
toxoplasmosis, compared to that in control group. Of
various mechanisms described in T. gondii for behavioral
alterations, increased testosterone seems to play a signifi-
cant role. Alterations of testosterone during latent toxo-
plasmosis can affect several behavioral, physiologic and
immunological parameters in a long time.
In this study the association of latent toxoplasmosis and
psychological disorders was not tested in patients. It is
suggested to further investigation of direct correlation
between latent toxoplasmosis and psychological disor-
ders in animal and human models.
ECLIA: electro chemiluminescence immunoassay; ELISA: enzyme-linked
immunosorbent assay; IgG: immunoglobulin G; PBST: phosphate buffered
saline, tween 20; HRP: hourseradish peroxidase; OPD: ortho phenylenedi-
amine; OD: optical density; 2D:4D ratio: second to fourth digit length ratio;
SPSS: statistical package for the social sciences; FSH: follicle stimulating
hormone; LH: luteinizing hormone.
Author contributions
HK designed the experiments and provided important advice for the experi-
ments and financial support. NZ collected the samples and performed the
experiments. MM and SS analyzed and interpreted the data and contributed
to manuscript preparation. NZ drafted the original manuscript. HK, SS and MM
reviewed and revised the manuscript. All authors read and approved the final
The authors would like to thank staff within the toxoplasmosis laboratory,
Department of Medical Parasitology and Mycology, Tehran University of Medi-
cal Sciences, Tehran, Iran, for their useful collaboration.
Competing interests
The authors declare no competing interests.
Availability of data and materials
Data that support the findings of this study are available on reasonable
request to the corresponding author.
Consent for publication
Not applicable (no individual person’s data).
Ethics approval and consent to participate
The study was approved by Ethical Committee of Tehran University of Medical
Sciences. Informed written consent was obtained from all participants before
being involved in the study. All participants signed an informed consent and
received a complete copy of the signed consent form
The study received no specific funding.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in pub-
lished maps and institutional affiliations.
Received: 10 March 2018 Accepted: 1 June 2018
1. Dubey JP. Toxoplasmosis of animals and humans. 2nd ed. Boca Raton:
CRC Press Inc.; 2010. p. 1–313.
2. Tenter AM, Heckeroth AR, Weiss LM. Toxoplasma gondii: from animals to
humans. Int J Parasitol. 2000;30:1217–58.
3. Selseleh M, Keshavarz H, Mohebali M, Shojaee S, Selseleh M, Eshragian
MR, Mansouri F, Modarressi MH. Production and evaluation of Toxoplasma
gondii recombinant GRA7 for serodiagnosis of human infections. Korean J
Parasitol. 2012;50:233–8.
4. Weiss LM, Dubey JP. Toxoplasmosis: a history of clinical observations. Int J
Parasitol. 2009;39(8):895–901.
5. Webster JP. Rats, cats, people and parasites: the impact of latent toxoplas-
mosis on behaviour. Microbes Infect. 2001;3:1037–45.
6. Mahmoudvand H, Ziaalia N, Ghazvini H, et al. Toxoplasma gondii infection
promotes neuroinflammation through cytokine networks and induced
hyperalgesia in BALB/c mice. Inflammation. 2016;39:405–12.
7. Alipour A, Shojaee S, Mohebali M, Tehranidoost M, Abdi Masoleh F, Kes-
havarz H. Toxoplasma infection in schizophrenia patients: a comparative
study with control group. Iran J Parasitol. 2011;6(2):31–7.
8. Mahmoudvand H, Ziaali N, Aghaei I, Sheibani V, Shojaee S, Keshavarz H,
Shabani M. The possible association between Toxoplasma gondii infection
and risk of anxiety and cognitive disorders in BALB/c mice. Pathogen
Glob Health. 2016;109(8):369–76.
9. Mahmoudvand H, Sheibani V, Shojaee S, Mirbadie SR, Keshavarz H,
Esmaeelpour K, Keyhani AR, Ziaali N. Toxoplasma gondii infection potenti-
ates cognitive impairments of Alzheimer’s disease in the BALB/C mice. J
Parasitol. 2016;102(6):629–35.
10. Hutchinson WM, Bradley M, Cheyne WM, Wells BW, Hay J. Behavioural
abnormalities in Toxoplasma-infected mice. Ann Trop Med Parasitol.
11. Witting PA. Learning capacity and memory of normal and Toxoplasma-
infected laboratory rats and mice. Z fur Parasitenkd. 1979;61:29–51.
Page 5 of 5
Zoueietal. BMC Res Notes (2018) 11:365
fast, convenient online submission
thorough peer review by experienced researchers in your field
rapid publication on acceptance
support for research data, including large and complex data types
gold Open Access which fosters wider collaboration and increased citations
maximum visibility for your research: over 100M website views per year
At BMC, research is always in progress.
Learn more
Ready to submit your research
? Choose BMC and benefit from:
12. Skallova A, Kodym P, Frynta D, Flegr J. The role of dopamine in Toxo-
plasma-induced behavioural alterations in mice: an ethological and
ethopharmacological study. Parasitology. 2006;133:525–35.
13. Moore J. Parasites and the behavior of animals. Oxford: Oxford University
Press; 2002. ISBN 9780195146530.
14. Kankova S, Sulc J, Nouzova K, Fajfrlik K, Frynta D, Flegr J. Women infected
with parasite Toxoplasma have more sons. Naturwissenschaften.
15. Kankova S, Kodym P, Frynta D, Vavrinova R, Kubena A, Flegr J. Influence
of latent toxoplasmosis on the secondary sex ratio in mice. Parasitology.
16. Cox RM, John-Alder HB. Testosterone has opposite effects on male
growth in lizards (Sceloporus spp.) with opposite patterns of sexual size
dimorphism. J Exp Biol. 2005;208:4679–87.
17. Zghair KH, AL-Qadhi BN, Mahmood SH. The effect of toxoplasmosis on
the level of some sex hormones in males blood donors in Baghdad. J
Parasit Dis. 2015;39:393–400.
18. Eslamirad Z, Hajihossein R, Ghorbanzadeh B, Alimohammadi M, Mosayebi
M, Didehdar M. Effects of Toxoplasma gondii infection in level of serum
testosterone in males with chronic toxoplasmosis. Iran J Parasitol.
19. Flegr J, LIindova J, Kodym P. Sex-dependent toxoplasmosis-associated
differences in testosterone concentration in humans. Parasitology.
20. Hillyer GV, de Galanes MS, Rodriguez-Perez J, Bjorland J, de Lagrava MS,
Guzman SR, et al. Use of the falcon assay screening test–enzyme-linked
immunosorbent assay (FAST-ELISA) and the enzyme-linked immunoelec-
trotransfer blot (EITB) to determine the prevalence of human fascioliasis
in the Bolivian Altiplano. Am J Trop Med Hyg. 1992;46(5):603–9.
21. Teimouri A, Azami SJ, Keshavarz H, Esmaeili F, Alimi R, Mavi SA, Shojaee
S. Anti-Toxoplasma activity of various molecular weights and concen-
trations of chitosan nanoparticles on tachyzoites of RH strain. Int J
Nanomed. 2018;13:1341–51.
22. Teimouri A, Modarressi MH, Shojaee S, et al. Detection of toxoplasma-
specific immunoglobulin G in human sera: performance comparison of
in house Dot-ELISA with ECLIA and ELISA. Eur J Clin Microbiol Infect Dis.
2018. https :// 6-018-3266-y.
23. Booth A, Granger DA, Mazur A, Kivlighan KT. Testosterone and social
behavior. Soc Forces. 2006;85(1):167–91.
24. Eisenegger C, Haushofer J, Fehr E. The role of testosterone in social inter-
action. Trends Cogn Sci. 2011;15(6):263–71.
25. Montoya ER, Terburg D, Bos PA, van Honk J. Testosterone, cortisol, and
serotonin as key regulators of social aggression: a review and theoretical
perspective. Motiv Emot. 2012;36(1):65–73.
26. House PK, Vyas A, Sapolsky R. Predator cat odors activate sexual arousal
pathways in brains of Toxoplasma gondii infected rats. PLoS ONE.
27. Lim A, Kumar V, Dass SAH, Vyas A. Toxoplasma gondii infection enhances
testicular steroidogenesis in rats. Mol Ecol. 2013;22:102–10.
28. Roberts F, Mets M, Ferguson N, Grady R. Histopathological features of
ocular toxoplasmosis in fetus and infant. J Opthal. 2001;119(1):51–8.
29. Abdoli A. Toxoplasma, testosterone, and behavior manipulation: the role
of parasite strain, host variations, and intensity of infection. Front Biol.
30. Kankova S, Holan V, Zajicova A, Kodym P, Flegr J. Modulation of immunity
in mice with latent toxoplasmosis—the experimental support for the
immunosuppression hypothesis of Toxoplasma-induced changes in
reproduction of mice and humans. Parasitol Res. 2010;107:1421–7.
31. Lindova J, Novotna M, Havlicek J, Jozifkova E, Skallova A, Kolbekova P,
Hodny Z, Kodym P, Flegr J. Gender differences in behavioural changes
induced by latent toxoplasmosis. Int J Parasitol. 2006;36:1485–92.
32. Lindova J, Kubena AA, Sturcova H, Krivohlava R, Novotna M, Rubesova
A, Havlicek J, Kodym P, Flegr J. Pattern of money allocation in experi-
mental games supports the stress hypothesis of gender differences
in Toxoplasma gondii-induced behavioural changes. Folia Parasitol.
33. Flegr J. Influence of latent toxoplasmosis on the phenotype of intermedi-
ate hosts. Folia Parasitol. 2010;57:81–7.
34. Webster JP. Rats, cats, people and parasites: the impact of latent toxoplas-
mosis on behaviour. Microbes Infect. 2001. https ://
-4579(01)01459 -9.
35. Hodkova H, Kolbekova P, Skallova A, Lindova J, Flegr J. Higher perceived
dominance in Toxoplasma infected men—a new evidence for role of
increased level of testosterone in toxoplasmosis- associated changes in
human behavior. Neuro Endocrinol Lett. 2007;28(2):110–4.
36. Shirbazou S, Abasian L, Meymand FT. Effects of Toxoplasma gondii
infection on plasma testosterone and cortisol level and stress index
on patients referred to Sina hospital, Tehran. Jundishapur J Microbiol.
37. Flegr J, Hruskov YM, Hodna Z, Novotna M, Hanusova J. Body height,
body mass index, waist-hip ratio, fluctuating asymmetry and second
to fourth digit ratio in subjects with latent toxoplasmosis. Parasitology.
38. Flegr J, Lindova J, Pivonkova V, Havlicek JB. Brief communication: latent
toxoplasmosis and salivary testosterone concentration important
confounding factors in second to fourth digit ratio studies. Am J Phys
Anthropol. 2008;137:479–84.
39. Flegr J. Influence of latent Toxoplasma infection on human personal-
ity, physiology and morphology: pros and cons of the Toxoplasma-
human model in studying the manipulation hypothesis. J Exp Biol.
40. Kratochvil L, Flegr J. Differences in the 2nd to 4th digit length ratio
in humans reflect shifts along the common allometric line. Biol Lett.
41. Kankova S, Kodym P, Flegr J. Direct evidence of Toxoplasma-induced
changes in serum testosterone in mice. Exp Parasitol. 2011;128:181–3.
42. Vallochi AL, Muccioli M, Martins C, Silveira C, Belfort R. The genotype of
Toxoplasma gondii strains causing ocular toxoplasmosis in humans in
Brazil. Am J Ophthalmol. 2005;139:350–1.
43. Abdoli A, Dalimi A, Movahedin M. Impaired reproductive function of
male rats infected with Toxoplasma gondii. Andrologia. 2012;44(Suppl
44. Oktenli C, Doganci L, Ozgurtas T, Araz RE, Tanyuksel M, Musabak U,
Sanisoglu SY, Yesilova Z, Erbil MK, Inal A. Transient hypogonadotrophic
hypogonadism in males with acute toxoplasmosis: suppressive
effect of interleukin-1beta on the secretion of GnRH. Hum Reprod.
... To our knowledge, this study is, worldwide, one of the few studies to analyze the impact of latent TG infection on the history of spontaneous abortion [18,[22][23][24][25][26], secondary sex ratio [28,[36][37][38][39], occurrences of pregnancy complications (such as the mode of delivery), the prevalence of spontaneous premature rupture of membranes, pregnancy-induced hypertensive disease [30,[40][41][42], preterm birth or prolonged pregnancy [12,43], with respect to neonatal outcome. The gestational age was established by the first or second-trimester scan in each patient. ...
... Previous studies have suggested that latent TG infection affects the course of pregnancy, thus seropositive pregnant women show a modified secondary sex ratio in newborns [28,29,[37][38][39], more spontaneous abortion [27,31,33,36], more prolonged pregnancies [43], obesity [47] or higher weight gain in pregnancy in Rh-negative women, higher pregnancy-induced hypertension disease rate [40,50] and higher prevalence of autoimmune thyroiditis [28,48,49]. In addition, previous publications mentioned that acute TG infection during pregnancy is associated with miscarriage [27] or congenital malformations in fetuses [2] and reactivation of latent infection or infection with another strain could also be a cause of congenital malformations [6,7]. ...
... Some published studies have analyzed the association between latent TG infection and the sex ratio at birth and concluded that women infected with TG have more sons [28,29,[36][37][38][39]. Many hypotheses have been raised to explain this association: modulation of the immune response and cytokine production [36] or increased testosterone levels in TG seropositive women [39]. ...
Full-text available
Background: Toxoplasma gondii (TG), a zoonotic protozoan parasite, belongs to a group of TORCH infectious agents, which can cause severe damage to the fetus if a primary infection occurs during pregnancy. After primary infection, TG rests lifelong in human organisms causing a latent infection. Most studies have analyzed the consequences of acute, but not latent, TG infection. This study analyzed the impact of latent toxoplasmosis on spontaneous abortion history, pregnancy complication rate and neonatal outcome. Methods: IgG and IgM anti-TG antibodies were tested in 806 pregnant women who were consulted at the Timisoara Clinical Emergency Hospital between 2008 and 2010. Demographic data, obstetrical history, and data about the pregnancy complications, birth and neonate were collected for each woman and comparisons between the groups, with and without latent TG infection, were made. Results: This study did not show differences between groups regarding the history of spontaneous abortion (OR = 1.288, p = 0.333), cesarean section (OR = 1.021, p = 0.884), placental abruption (OR 0.995, p = 0.266), pregnancy-induced hypertension rate (OR 1.083, p = 0.846), secondary sex ratio (1.043, p = 0.776), 1' APGAR score at birth (p = 0.544), gestational age at birth (p = 0.491) or birth weight (p = 0.257). Conclusions: The observed differences between the rate of pregnancy complications in the two groups of pregnant women with and without latent infection with TG, did not reach a statistical significance.
... Since T. gondii can invade cells of the male reproductive system, any damage to these cells can compromise male fertility, promoting an acute inflammatory environment associated with abnormal testosterone levels (Staurengo-Ferrari et al., 2021). In vivo and clinical studies have shown that T. gondii affects the male reproductive system by causing changes in the activities of the luteinizing hormone receptor and steroidogenic enzymes (Zouei et al., 2018), thereby inducing a significant increase in the synthesis of testosterone by the Leydig cells (Vyas, 2013). High testosterone levels have been linked to increased sexual attraction and are known to reduce fear, which may result in higher transmission of the parasite through sexual and trophic routes in a male rat model (Lim et al., 2013). ...
... Studies in mice have shown that T. gondii infection disrupts the neuroendocrine reproductive control axis and hormonal homeostasis (Stahl et al., 1985). Furthermore, men infected with T. gondii have a higher concentration of total and free testosterone in both acute and chronic cases (Zghair et al., 2015;Zouei et al., 2018). The increase in testosterone induced by T. gondii infection seems to be associated with greater sexual attractiveness and attenuation of the innate fear mechanisms of infected individuals, favoring the transmission and maintenance of the biological cycle of the parasite (Lim et al., 2013). ...
Toxoplasma gondii, a protozoan parasite, is responsible for toxoplasmosis. The available therapy for patients with toxoplasmosis involves a combination of pyrimethamine and sulfadiazine, which have several adverse effects, including bone marrow suppression, megaloblastic anemia, leukopenia, and granulocytopenia. The development of therapeutic alternatives is essential for the management of toxoplasmosis, emphasizing the recent advances in nanomedicine. This study aimed to evaluate the in vitro effects of biogenic silver nanoparticles (AgNp-Bio) on tachyzoite forms and Leydig cells infected with T. gondii. We observed that the AgNp-Bio reduced the viability of the tachyzoites and did not exhibit cytotoxicity against Leydig cells at low concentrations. Additionally, treatment with AgNp-Bio reduced the rate of infection and proliferation of the parasite, and lowered the testosterone levels in the infected cells. It increased the levels of IL-6 and TNF-α and reduced the levels of IL- 10. Among the morphological and ultrastructural changes, AgNp-Bio induced a reduction in the number of intracellular tachyzoites and caused changes in the tachyzoites with accumulation of autophagic vacuoles and a decrease in the number of tachyzoites inside the parasitophorous vacuoles. Collectively, our data demonstrate that the AgNp-Bio affect T. gondii tachyzoites by activating microbicidal and inflammatory mechanisms and could be a potential alternative treatment for toxoplasmosis.
... However, findings from these studies are mixed. On the one hand, T. gondiiinfected humans, especially adult males, often exhibit elevated circulating levels of testosterone (Flegr et al., 2008;Shirbazou et al., 2011;Zghair et al., 2015;Zouei et al., 2018). Testes of male lab rats infected with T. gondii also produce elevated levels of testosterone, potentially due to the upregulation of genes involved in testosterone production in infected hosts (Lim et al., 2013). ...
... Other studies have found patterns that depart from those observed within the present study. For example, several human studies have reported positive correlations between T. gondii infection and circulating levels of testosterone (Flegr et al., 2008;Shirbazou et al., 2011;Zghair et al., 2015;Zouei et al., 2018). These positive correlations are in line with the host-manipulation hypothesis because elevated testosterone can facilitate increased boldness and thus expose infected hosts to feline predators and the parasite's definitive host. ...
Full-text available
Toxoplasma gondii is a common parasite that infects warm-blooded animals and influences host physiology. T. gondii is known to target the host's central nervous system, affecting circulating levels of steroid hormones, fear-related behaviors, and health, although these effects appear to vary among host taxa. Here, we investigated the relationship between T. gondii infection and levels of plasma testosterone and cortisol within a wild population of spotted hyenas (Crocuta crocuta, n = 109). In our analyses, we accounted for age and sex via stratified regression analyses. We detected a negative association between circulating plasma testosterone and T. gondii infection among female cubs and subadults as well as adult male hyenas. We found no associations between T. gondii infection and cortisol in any age class or sex group of hyenas. Our work adds to a growing body of literature by characterizing the relationship between T. gondii infection and physiology in a novel host in its natural habitat. In a broader context, our findings indicate that responses to infection vary with characteristics of the host and point to a clear need for additional studies and priorities for future work that include diverse taxa and ecological settings.
... Previous studies revealed an association between T. gondii infection and testosterone alterations in humans [11,12,24], experimentally infected rodents [14,15,25] and in cell lines [26]. A recent study by Staurengo-Ferrari et al. [26] demonstrated that T. gondii RH strain augmented testosterone synthesis in Leydig cells 48 h postinfection in vitro. ...
Purpose Toxoplasmosis can induce various hormonal and behavioral alterations in humans and rodents. Previous studies revealed alterations of sex hormones; especially testosterone, in infected humans and rodents, but little is known about the effects of sex hormones on the propagation of T. gondii. Hence, we aimed to investigate whether testosterone and progesterone influence on T. gondii propagation in neural cells. Methods The glioblastoma cells (U-87MG) were treated with different concentrations of testosterone and progesterone and the infection was done by tachyzoites of the RH strain of T. gondii. The number of infected cells, viability of T. gondii-infected cells, and parasite burden were measured by direct counting under a light microscope, MTT assay, and quantitative real-time PCR (qPCR), respectively. Results The results showed that testosterone at concentrations of 100 and 250 nM significantly increased the number of infected cells and parasite burden 24 and 48 h post-treatment compared to untreated controls. Progesterone had no significant effects in the same manner. Conclusion The results indicated that testosterone could augment the propagation of T. gondii in in vitro.
... Some researchers have suggested that a higher level of testosterone could be responsible for at least some of the toxoplasmosis-associated shifts in human and animal behavior [34]. In a study on the association of latent toxoplasmosis and levels of serum testosterone in humans, researchers found a higher testosterone concentration in T. gondii seropositive individuals than in T. gondii seronegative ones [35]. In a study of students, researchers found that T. gondiiinfected men had a higher concentration of testosterone and T. gondii-infected women had a lower concentration of testosterone than T. gondii-free controls [36]. ...
Full-text available
We determined the association between T. gondii seropositivity and a history of sexual promiscuity. The study included 3933 people (mean age: 41.81 ± 14.31 years) who attended public health facilities. Face-to-face interviews were used to collect data. Enzyme immunoassays were used to determine anti-T. gondii IgG and IgM antibodies. Anti-T. gondii IgG antibodies were found in 57 (18.1%) of 315 individuals with sexual promiscuity and in 374 (10.3%) of 3618 individuals without this practice (OR: 1.91; 95% CI: 1.41-2.60; p < 0.0001). High (>150 IU/mL) levels of anti-T. gondii IgG antibodies were found in 29 (9.2%) of the 315 participants with sexual promiscuity and in 167 (4.6%) of the 3618 participants without this history (OR: 2.09; 95% CI: 1.38-3.16; p = 0.0003). The association of sexual promiscuity with T. gondii seropositivity and serointensity was observed in men but not in women. Sexual promiscuity was associated with T. gondii seropositivity in all age groups studied (≤30 years, 31-50 years, and >50 years) and with T. gondii serointensity in two age groups (≤30 years, and >50 years). No difference in the frequencies of anti-T. gondii IgM antibodies among the groups was found. Our findings indicate that T. gondii seropositivity and serointensity are associated with sexual promiscuity.
Full-text available
Toxoplasma gondii is a protozoan parasite capable of infecting any warm-blooded species and can increase risk-taking in intermediate hosts. Despite extensive laboratory research on the effects of T. gondii infection on behaviour, little is understood about the effects of toxoplasmosis on wild intermediate host behavior. Yellowstone National Park, Wyoming, USA, has a diverse carnivore community including gray wolves (Canis lupus) and cougars (Puma concolor), intermediate and definitive hosts of T. gondii, respectively. Here, we used 26 years of wolf behavioural, spatial, and serological data to show that wolf territory overlap with areas of high cougar density was an important predictor of infection. In addition, seropositive wolves were more likely to make high-risk decisions such as dispersing and becoming a pack leader, both factors critical to individual fitness and wolf vital rates. Due to the social hierarchy within a wolf pack, we hypothesize that the behavioural effects of toxoplasmosis may create a feedback loop that increases spatial overlap and disease transmission between wolves and cougars. These findings demonstrate that parasites have important implications for intermediate hosts, beyond acute infections, through behavioural impacts. Particularly in a social species, these impacts can surge beyond individuals to affect groups, populations, and even ecosystem processes.
Full-text available
During chronic infection, the single celled parasite, Toxoplasma gondii , can migrate to the brain where it has been associated with altered dopamine function and the capacity to modulate host behavior, increasing risk of neurocognitive disorders. Here we explore alterations in dopamine-related behavior in a new mouse model based on stimulant (cocaine)-induced hyperactivity. In combination with cocaine, infection resulted in heightened sensorimotor deficits and impairment in prepulse inhibition response, which are commonly disrupted in neuropsychiatric conditions. To identify molecular pathways in the brain affected by chronic T . gondii infection, we investigated patterns of gene expression. As expected, infection was associated with an enrichment of genes associated with general immune response pathways, that otherwise limits statistical power to identify more informative pathways. To overcome this limitation and focus on pathways of neurological relevance, we developed a novel context enrichment approach that relies on a customized ontology. Applying this approach, we identified genes that exhibited unexpected patterns of expression arising from the combination of cocaine exposure and infection. These include sets of genes which exhibited dampened response to cocaine in infected mice, suggesting a possible mechanism for some observed behaviors and a neuroprotective effect that may be advantageous to parasite persistence. This model offers a powerful new approach to dissect the molecular pathways by which T . gondii infection contributes to neurocognitive disorders.
Full-text available
Introduction/Aims: Toxoplasmosis modifies various hormones and cytokines in the infected hosts which may result in several disorders. This study was conducted to assess testosterone, DHEA, and prolactin concentration levels among Toxoplasma gondii infected and uninfected infertile couples. Methods: Blood samples were collected and sera were separated. The sera were analyzed for the detection of anti-Toxoplasma (IgG& IgM) antibodies using commercial ELISA kits. The level of DHEA was measured by ELISA and the levels of testosterone and prolactin were evaluated by enzyme-linked fluorescent assay (ELFA, VIDAS). Results: The overall seroprevalence of toxoplasmosis was 58.0% (218/376). Among women, 56.9% (107/188) and 6.5% (7/107) were positive for anti-T. gondii antibodies IgG and IgM, respectively. The IgG and IgM were detected in the sera of 111/188 (59.0%) and 9/111 (8.1%) in male subjects, respectively. A positive association was observed between T. gondii infection and the upper and lower ranges of the normal value of testosterone in males (x 2 = 6.8, p = 0.033) but not in females (x 2 = 0.62, p = 0.99). A positive correlation was seen between toxoplasmosis and the upper and lower ranges of the normal value of prolactin in females (x 2 = 6.5, p = 0.039) but not in male cases (x 2 = 1.06, p = 0.59). Conclusion: Our results demonstrated no statistically significant differences between the level of sexual hormones between Toxoplasma-infected individuals and Toxoplasma-free subjects suffering from infertility. These findings suggest that further studies should be performed on infertile cases with large sample sizes in a case-control format.
Full-text available
Background Parasites are among the main factors that negatively impact the health and reproductive success of organisms. However, if parasites diminish a host’s health and attractiveness to such an extent that finding a mate becomes almost impossible, the parasite would decrease its odds of reproducing and passing to the next generation. There is evidence that Toxoplasma gondii ( T. gondii ) manipulates phenotypic characteristics of its intermediate hosts to increase its spread. However, whether T. gondii manipulates phenotypic characteristics in humans remains poorly studied. Therefore, the present research had two main aims: (1) To compare traits associated with health and parasite resistance in Toxoplasma -infected and non-infected subjects. (2) To investigate whether other people perceive differences in attractiveness and health between Toxoplasma -infected and non-infected subjects of both sexes. Methods For the first aim, Toxoplasma -infected ( n = 35) and non-infected subjects ( n = 178) were compared for self-perceived attractiveness, number of sexual partners, number of minor ailments, body mass index, mate value, handgrip strength, facial fluctuating asymmetry, and facial width-to-height ratio. For the second aim, an independent group of 205 raters (59 men and 146 women) evaluated the attractiveness and perceived health of facial pictures of Toxoplasma -infected and non-infected subjects. Results First, we found that infected men had lower facial fluctuating asymmetry whereas infected women had lower body mass, lower body mass index, a tendency for lower facial fluctuating asymmetry, higher self-perceived attractiveness, and a higher number of sexual partners than non-infected ones. Then, we found that infected men and women were rated as more attractive and healthier than non-infected ones. Conclusions Our results suggest that some sexually transmitted parasites, such as T. gondii , may produce changes in the appearance and behavior of the human host, either as a by-product of the infection or as the result of the manipulation of the parasite to increase its spread to new hosts. Taken together, these results lay the foundation for future research on the manipulation of the human host by sexually transmitted pathogens and parasites.
Full-text available
In the current study, performance of electrochemiluminescence immunoassay (ECLIA) in detection of anti-toxoplasma IgG in human sera was compared with that of enzyme-linked immunosorbent assay (ELISA). Furthermore, performance of an in house Dot-ELISA in detection of anti-toxoplasma IgG was compared with that of ECLIA and ELISA. In total, 219 human sera were tested to detect anti-toxoplasma IgG using Dynex DS2® and Roche Cobas® e411 Automated Analyzers. Discordant results rechecked using immunofluorescence assay (IFA). Then, sera were used in an in house Dot-ELISA to assess toxoplasma-specific IgG. Of the 219 samples, two samples were found undetermined using ECLIA but reactive using ELISA. Using IFA, the two sera were reported unreactive. Furthermore, two samples were found reactive using ECLIA and unreactive using ELISA. These samples were reported reactive using IFA. The overall agreement for the two former methods was 98% (rZ0.98.1; P < 0.001). The intrinsic parameters calculated for in house Dot-ELISA included sensitivity of 79.5, specificity of 78.2, and accuracy of 78.9%, compared to ECLIA and ELISA. Positive and negative predictive values included 82.9 and 74.2%, respectively. A 100% sensitivity was found in in house Dot-ELISA for highly reactive sera in ECLIA and ELISA. ECLIA is appropriate for the first-line serological screening tests and can replace ELISA due to high speed, sensitivity, and specificity, particularly in large laboratories. Dot-ELISA is a rapid, sensitive, specific, cost-effective, user-friendly, and field-portable technique and hence can be used for screening toxoplasmosis, especially in rural fields or less equipped laboratories.
Full-text available
Background Natural polysaccharides such as chitosan (CS) are widely used as antimicrobial agents. In recent years, and considering that CS has a strong antimicrobial potential, interest has been focused on antimicrobial activity of chitosan nanoparticles (CS NPs). The main factors affecting the antibacterial activity of chitosan include molecular weight (MW) and concentration. In this regard, the aim of this study was to produce various MWs and concentrations of CS NPs, through the ionic gelation method, and investigate their potential anti-parasitic activity against tachyzoites of Toxoplasma gondii RH strain. Materials and methods The MWs and degree of deacetylation of the CS were characterized using viscometric and acid–base titration methods, respectively. The efficacy of various MWs and concentrations of NPs was assessed by performing in vitro experiments for tachyzoites of T. gondii RH strain, such as MTT assay, scanning electron microscopy, bioassay in mice and PCR. In vivo experiment was carried out in BALB/c mice which were inoculated with tachyzoites of T. gondii RH strain and treated with various MWs of CS NPs. Results The results of in vitro and in vivo experiments revealed that anti-Toxoplasma activity strengthened as the CS NPs concentration increased and the MW decreased. In vitro experiment showed 100% mortality of tachyzoites at 500 and 1,000 ppm concentrations of low molecular weight (LMW) CS NPs after 180 min and at 2,000 ppm after 120 min. Furthermore, a 100% mortality of tachyzoites was observed at 1,000 and 2,000 ppm concentrations of medium molecular weight (MMW) CS NPs and at 2,000 ppm concentration of high molecular weight (HMW) CS NPs after 180 min. Growth inhibition rates of tachyzoites in peritoneal exudates of mice receiving low, medium and high MWs of CS NPs were found to be 86%, 84% and 79% respectively, compared to those of mice in sulfadiazine treatment group (positive control). Conclusion Various MWs of CS NPs exhibited great anti-Toxoplasma efficiency against tachyzoites of RH strain, with the greatest efficacy shown by LMW CS NPs in both experiments. It seems that CS NPs can be used as an alternative natural medicine in the treatment of toxoplasmosis.
Full-text available
Here, we hypothesized that in chronic Toxoplasma gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and potentiate cognitive impairments in BALB/c mice with Alzheimer's disease (AD). The animal model of Toxoplasma infection was established by the intraperitoneal inoculation of 20-25 tissue cysts from Tehran strain of T. gondii. We injected amyloid-beta 1-42 peptide (A1-42, 1 and 2 µL) into the hippocampus of BALB/c mice to establish an animal model of AD. The behavioral experiments such as spatial learning and memory were performed using Morris water maze test. The mRNA levels of TNF-, IL-1, IFN-, and inducible nitric oxide synthase (iNOS) were examined by real-time PCR. We found that T. gondii infection caused AD-like symptoms and impaired learning and memory functions of the infected BALB/c mice. We also found that in Toxoplasma infection + A1-42 (1 µL) group, T. gondii infection could potentiate AD in infected mice receiving sub-dose of A1-42 (1 µL) and caused considerable impairment in learning and memory functions similar to AD group. Comparison of the results demonstrated that mRNA levels of IL-1, TNF-, IFN-, and also iNOS significantly (P < 0.001) increased in T. gondii + A1-42 (1 µL) in comparison with the other tested groups. The obtained results showed that chronic T. gondii infection communication among immune cells promotes neuroinflammation through cytokine networks and induce pathological progression of AD in the mice brain, whereas, neuroanatomical Toxoplasma tissue cysts presence in the brain could also affect the behavioral functions in T. gondii infected mice.
Full-text available
There are conflicting reports concerning the association of Toxoplasma gondii infection with increased risk of mental disorders. This investigation will provide a good understanding about defining the possible association between T. gondii exposure and risk of anxiety and cognitive alterations. Besides, a secondary objective of this study was to determine the effect of pioglitazone administration on the possible alterations induced by T. gondii exposure. Male BALB/c mice were used for this study. The animal model of Toxoplasma infection was established by the intraperitoneal inoculation of 20-25 tissue cysts from Tehran strain of T. gondii. Pioglitazone (20 mg/kg, i.p.1/day) was administered to the animals for 2 weeks before behavioural tests. Behavioural tests including open-field, elevated plus-maze and passive avoidance learning were evaluated in the groups. Since cytokines were implicated as a contributing factor for mood disorders, the mRNA levels of TNF-α, IL-1β, IL-6 as well as inducible nitric oxide synthase (iNOs) were examined by real-time PCR. Findings demonstrated that T. gondii caused anxiety-like symptoms and impaired cognitive functions of the infected BALB/c mice, whereas pioglitazone, a peroxisome proliferator-activated receptor agonist, showed a promising effect against the cognitive impairments induced by Toxoplasma infection. The results also revealed that the mRNA levels of the aforementioned cytokines were significantly (p < 0.05) increased in the infected mice compared to the uninfected BALB/c ones. Pioglitazone can be offered as a potential neuroprotective agent in the treatment of patients with T. gondii infection that manifests anxiety and cognitive impairments; however, further studies are needed to clarify the exact mechanisms.
Full-text available
We hypothesized that in Toxoplasma gondii infection, communication among immune cells promotes neuroinflammation through cytokine networks and induces pain sensitivity under conditions of neuropathic pain. The animal model of Toxoplasma infection was established by the intraperitoneal inoculation of 20-25 tissue cysts from Tehran strain of T. gondii to BALB/c mice. Amitriptyline (20 mg/kg, i.p., 1/day) administrated to animals for 7 days before behavioral tests. Pain behavioral tests including tail flick, hot plate, and formalin test were evaluated in all the groups. The mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were examined by real-time PCR. Results revealed that T. gondii induce hyperalgesia in the infected mice, whereas amitriptyline showed a promising effect against the hyperalgesia induced by Toxoplasma infection. The mRNA levels of the aforementioned cytokines significantly (P < 0.05) increased in the infected mice compared to the uninfected ones. Obtained findings suggested that T. gondii infection could promote neuroinflammation through cytokine networks and induced hyperalgesia in BALB/c mice, whereas amitriptyline as an analgesic drug reverses them.
Full-text available
Toxoplasma gondii is a unique intracellular parasite, which infect a large proportion of the world population, but uncommonly causes clinically significant disease. The present study was performed to estimate the prevalence of toxoplasmosis in 400 apparently healthy blood donor males, their ages were between 18 and 57 years using enzyme linked immunosorbent assay, and to examine the effects of infection on total testosterone, free testosterone and follicle stimulating hormone (FSH) levels in their sera. Seroprevalence showed 10 (2.5 %) and 121 (30 %) of them had IgM and IgG antibodies respectively. Both acute and chronic toxoplasmosis in males recorded higher significant (P < 0.05) mean concentration for total and free testosterone hormone, they were 12.188 ± 0.73, 7.837 ± 0.52 ng/ml and 44.121 ± 1.76, 27.984 ± 0.94 pg/ml respectively. The mean concentration of FSH revealed non-significant (P < 0.05) differences in both disease activities, they were 6.41 ± 0.47 and 6.515 ± 0.51 IU/ml respectively.
Full-text available
Toxoplasma gondii is an intracellular protozoan parasite that infects human and animals. Toxoplasma parasites are isolated from different parts of animals even from semen but there are little information about the effect of toxoplasmosis on fertility in animals and humans. In present study, the effect of chronic toxoplasmosis on serum levels of testosterone in men was studied. In this case-control study, 1026 men referred to Arak Post Marriage Center were selected. Three ml of blood samples were collected and sera separated by centrifugation at room temperature. These sera were analyzed for detection of anti-T. gondii IgG antibody. Next 365 positive sera were selected as cases and also the same number of negative sera (365) as controls. Finally the level of testosterone was analyzed for the cases and controls samples. Serological tests on the sera of 1,026 men in Arak City showed that 365 of them had anti-Toxoplasma antibody. Comparison of testosterone concentration in case and control groups showed that testosterone concentration in case group was less than control group and this difference was statistically significant (P<0.05). The chronic toxoplasmosis could affect reproductive parameters in men.
Full-text available
Toxoplasma gondii is an intracellular parasite involved in the etiology of various behavioral and hormonal alterations in humans and rodents. Various mechanisms, including induction changes of testosterone production, have been proposed in the etiology of behavioral alterations during T. gondii infection. However, controversy remains about the effects of T. gondii infection on testosterone production; in some studies, increased levels of testosterone were reported, whereas other studies reported decreased levels. This is a significant point, because testosterone has been shown to play important roles in various processes, from reproduction to fear and behavior. This contradiction seems to indicate that different factors—primarily parasite strains and host variations—have diverse effects on the intensity of T. gondii infection, which consequently has diverse effects on testosterone production and behavioral alterations. This paper reviews the role of parasite strains, host variations, and intensity of T. gondii infection on behavioral alterations and testosterone production, as well as the role of testosterone in the etiology of these alterations during toxoplasmosis.
Found worldwide from Alaska to Australasia, Toxoplasma gondii knows no geographic boundaries. The protozoan is the source of one of the most common parasitic infections in humans, livestock, companion animals, and wildlife, and has gained notoriety with its inclusion on the list of potential bioterrorism microbes. In the two decades since the publication of the first edition of Toxoplasmosis of Animals and Humans there has been an explosion of knowledge concerning T. gondii and toxoplasmosis. Still used extensively as a cell model, its genome has recently been published making it a subject of even greater scientific interest. Keeping the organizational style that made the previous edition so popular and usable, this second edition has been completely revised and updated. New in the Second Edition: Expanded information on the cultivation, maintenance, and preservation of T. gondii Expanded information on the cell biology and molecular biology of the parasite Reviews all literature from the past 20 years for each domestic animal Summarizes information on the worldwide prevalence of toxoplasmosis in pregnant women and the devastating disease it can cause in newborn Written by one of the pioneers of the field, the book provides unique information on all known host types for this parasite. It distills the voluminous and potentially confusing scientific literature that has grown geometrically in the 20 years since the publication of the first edition into a comprehensive resource. The single author approach ensures a strong foundation in the biology and a seamless integration of topics. The new edition of this groundbreaking work is the only volume to cover toxoplasmosis of animals and humans thoroughly in one source. It supplies an entry point to further research by cutting through the morass of literature to identify the most relevant references.
Introduction and objective: Toxoplasma gondii is an intra cellular protozoan parasite which infects 30 to 60% of the world population. A wide range of toxoplasmosis conditions has been studied, but there are still unknown damages which must be explored. In the present research, the effect of this parasite on testosterone and cortisol changes in the infected men and women was examined. Materials and methods: A total of 180 patients (73 females and 107 males), were examined for lgG anti-Toxoplasma antibody, cortisol and testosterone in their plasma. In addition, the patients also filled in personality questionnaire DASS21 (depression, anxiety, and stress). Results: Results showed that 24(%13/33) females and 39(%20) males were positive with lgG anti-Toxoplasma antibody, respectively. A statistically significant correlation between Toxoplasma infection and testosterone and cortisol increase in women and men were observed. Stress and anxiety index also increased in men and women whereas depression index increased only in men. Conclusion: The results show a direct relation between raise Toxoplasma infection and cortisol, and testosterone increase in bout men and women and high DASS21 test score in Toxoplasma infected group. Significance and impact of the study: Our results may indicate that following Toxoplasma infection, the probability of stressful condition is high.