BACKGROUND
toxoplasmosis is a widespread zoonotic parasitic infection.
it is estimated that about one third of the world population is chronically infected with toxoplasma gondii.
felids are the only definitive hosts of the parasite and can shed millions of environmentally resistant oocysts in their feces if they become infected  <cit> .
the oocysts can remain infectious for more than 1 year in unfrozen and moist soil  <cit>  and can cause outbreaks of toxoplasmosis.
this is evidenced by the large waterborne outbreak of toxoplasmosis in canada in  <dig> that was epidemiologically linked to oocyst contamination of a water reservoir in british columbia  <cit> .
cats were introduced to qatar in the 1960s to control the high rodent population in the country, but subsequently they in turn reproduced rapidly  <cit> .
the current density of cats in qatar may pose a risk for humans, as cats are natural hosts for a wide range of zoonotic pathogens, including t. gondii.
the overall seroprevalence of t. gondii among the qatari human population has been estimated at  <dig> % with a progressive rise from <4% in the 1 year old group to  <dig> % at >45 years of age  <cit> .
such observations provide further evidence for the increased risk of infection with increasing age through longer exposure time.
as cats shed toxoplasma oocysts for only a short period of time after initial infection, detection of patent infections in cat populations  is likely to underestimate the number of animals that have been exposed to infection  <cit> .
however, t. gondii elicits strong antibody responses in its hosts and therefore assessment of seroprevalence is an alternative approach for studying the epidemiology of this pathogen.
estimates of antibody prevalence in the cat population also provide another useful indicator of environmental contamination  <cit> .
the current study is the first to estimate the seroprevalence of t. gondii in the feral cat population in qatar.
methods
sample collection
feral cats were caught live as part of the routine activities of the qatar cat control unit as described previously  <cit> .
briefly, trapped adult cats that were eligible for the trap-neuter-return program were transported to a shelter for sterilization.
for each animal the sex, the area, and the season of sampling were recorded.
in the current study, sampling began in september  <dig>  and ended in september  <dig> .
cats from both urban  and sub-urban  areas were investigated in this study.
within each sector, traps were set out in places most likely to be frequented by cats at night, i.e.
in alleyways, in back yards close to houses, and near to rubbish bins and municipal garbage containers.
blood was drawn by experienced veterinarians complying strictly with animal welfare guidelines as stipulated by the national institutional animal care and use committee of qatar.
blood samples were then centrifuged at 5000 × g for 20 min at room temperature and the resulting supernatants were collected and used for serology.
serology
a total number of  <dig> sera  were tested for t. gondii igg antibodies using commercially available toxoplasma gondii antigen .
two-fold serial dilutions, in phosphate buffered saline , were made from 1: <dig> to 1: <dig> and tested with a modified agglutination test , as previously described  <cit> .
samples that were positive at a dilution of 1: <dig> were further diluted in a second run to a dilution of 1: <dig>  for antibody titration, and those positive at 1: <dig>  were diluted in a third run until no further agglutination was evident.
positive controls  and negative controls  were included in each test.
agglutination in at least half of the “u” well bottoms of a microplate was accepted as a positive reaction.
in the case of complete sedimentation on the well bottom with no sign of agglutination, the sample was recorded as negative, i.e.
no evidence of t. gondii antibodies in the serum.
a titer  of  <dig> or higher was considered positive.
statistical analysis
prevalence values  are given with 95% confidence limits , calculated by bespoke software based on the tables of rohlf and sokal  <cit> .
for analysis of seroprevalence, we used maximum likelihood techniques based on log linear analysis of contingency tables in the software package ibm spss statistics version  <dig> .
initially, full factorial models were fitted, incorporating as factors sex , area  and season .
infection, reflecting the presence or absence of antibodies to t. gondii  was coded as a binary factor, and the cut-off for statistical significance was considered to be a p value of  <dig>    <cit> .
for analysis of quantitative data we first ranked the titers on a scale from  <dig> to  <dig>  where 0 = no agglutination, 1 = maximum agglutination at 1: <dig> and so on to 8 = agglutination at dilutions higher than 1: <dig> .
we used a zero-inflated model in r version  <dig> .
<dig>  that analyzed a binomial process  and a poisson  for the rest.
RESULTS
of the  <dig> feral cats  tested,  <dig>  were positive for t. gondii antibodies.
four samples presented prozone effects with negative results at the low dilution of 1: <dig> and positive agglutination at higher dilutions ≥ 1: <dig> .
the frequency distribution of antibody titers among the sampled cats is shown in fig.
<dig>  and the bimodal distribution of antibody titres, with peaks in the lower and top ends of the positive range can be clearly seen.fig.
<dig> frequency distribution of antibody titres among the sampled cats.
the figure shows the number of cats for which no antibody was detected  and those that had detectable antibody.
titres for the latter are given as the reciprocal of the maximum dilution  at which agglutination was detected and these fall into two peaks.
columns filled with stippled shading indicate the numbers of cats with titres in the lower intensity antibody range and those filled in black represent cats with the higher titres
seroprevalence of t. gondii was similar in males and females:  <dig> %  and  <dig> %  respectively.
with season and area taken into account, the difference between the sexes was not significant .
however, when the prevalence of antibodies in male and female cats was plotted separately against serum dilution , there was a significant effect of host sex at high antibody titers .fig.
<dig> the effect of host sex and season on the percentage of cat sera showing agglutination at varying dilutions of serum.
percentage values  are given with 95% confidence limits  for each level of serum dilution.
a effect of host sex .
b effect of season .
for statistical analysis see text
seroprevalence was similar in cats from urban and sub-urban areas  and no significant difference between areas was detected whether testing overall positivity , or positivity at specific dilutions of serum.
the number of cats sampled in the summer was  <dig>  and  <dig> in the winter months.
there was a significant effect of season on seropositivity .
seroprevalence was higher in the summer months  in contrast to the winter .
quantitative analysis was in general in agreement with these conclusions.
based on the zero-inflated model and a binomial process in which the high responders  were coded as  <dig>  and the rest as zero, the occurrence of the highest titers  was affected significantly only by host sex .
males  had a lower frequency of high titers than females , as found in the earlier log linear model given above.
discussion
this study demonstrated a high overall seroprevalence of t. gondii antibodies in the feral cat population in qatar.
seroprevalence was higher than values reported from neighboring countries, as for example  <dig> % in kuwait  <cit>  and  <dig> % in iraq  <cit> .
similar seroprevalences to those recorded in this study have been observed mainly among cats from tropical areas: ethiopia with  <dig> %  <cit>  and the amazon with  <dig> %  <cit> .
while the present work did not find an overall significant difference in seroprevalence between male and female cats as observed elsewhere  <cit> , higher antibody titers were detected in female cats when analysis was restricted to the high dilutions  which is in accordance with other reports  <cit> .
however our observation of some female cats expressing more intense antibody responses than male cats contrasts with the conclusions reached by miro et al.
<cit> , who reported in their study that stray male cats had significantly higher seroprevalence.
the authors linked their findings to differences in the territorial habits of male and female cats, as male cats are more likely to wander and thus experience more access to contaminated sources  <cit> .
although ecological, social and epidemiological factors may account for some of the female biased antibody responses in our study, hormone-influenced immunological mechanisms have been proposed as the more likely mechanism underlying sex-biased parasitism with t. gondii  <cit> .
cat bioassays have not provided any clear evidence of sex-bias in the occurrence of toxoplasmosis  <cit> .
however, experimental studies in mice have shown that females are more susceptible than males to t. gondii infection and develop more severe cerebral inflammation.
they are more likely to die following infection than males  <cit> .
female mice that survived the acute phase and developed chronic infections harbored more cysts in their brains than did surviving males.
gonadectomy of female mice was shown to reduce the development of tissue cysts caused by t. gondii infection, whereas estrogen administration was found to exacerbate the infection  <cit> .
it remains unknown when the cats that tested positive had acquired the infection.
the low intensity responses  which were recorded in more than half of the cats in our study suggest antibodies from a past infection but may also include cats that have very recently been exposed to the parasite, and have not yet developed the maximum response.
the cats that showed intense antibody responses  are more likely to be cats that had acquired the infection recently but after a sufficient time to mount the response  <cit> .
since the prevalence of high intensity antibody responses was almost identical in both winter and summer months, this indicates that there is a persistent source of t. gondii infection in the environment in which the cats live.
moreover, the consistently high seroprevalence in both urban and sub-urban areas of qatar suggests a high level of t. gondii contamination throughout the country.
the large home ranges of feral cats, which can stretch to 10 km <dig>  implies widespread contamination of the environment, especially given that some reports have documented cats travelling up to 45 km in just 2 days  <cit> .
domestic and stray/feral cats are the same species  and the main difference between them is their lifestyle.
in contrast to domestic animals, feral cats are unowned and live in the streets, alleys, farm buildings, factories, wharves or abandoned vehicles.
they may be semi dependent on humans from whom they may receive some food.
it has been reported elsewhere that  <dig> % of cats fed table leftovers are toxoplasma seropositive with a majority showing high igg antibodies titers  <cit> .
these free-roaming cats are exposed to a wide variety of pathogens, and have been shown to be excellent sentinels of infectious and parasitic diseases.
consequently they provide useful information on circulation of pathogens in domestic and wild ecosystems  <cit> .
most cats are thought to become infected with t. gondii after weaning when they begin to hunt for food.
outdoor access facilitates hunting behavior, as in the netherlands where 93% of the cats with free outdoor access exhibited hunting behavior  <cit> .
stray cats and cats with outdoor access usually acquire the infection from hunting rather than from the ingestion of oocysts  <cit> .
hence the recommendation to pet owners that to protect their cats from t. gondii infection the hunting of small prey should be discouraged/prevented, and that all meat served to their pet cats should be thoroughly cooked and/or frozen before cooking  <cit> .
in a study conducted in italy, it was suggested that infected intermediate hosts that are prey for cats are more available in the summer season  <cit> .
a recent analysis reported a correlation between the geolatitude  and humidity  and occurrence of toxoplasmosis  <cit> .
the efficiency of transmission may therefore differ between seasons in qatar, with a higher risk of exposure in the summer months .
qatar typically experiences two seasons.
in the summer season, daytime temperatures frequently exceed 45 °c and seldom fall below 18 °c at night.
humidity peaks in august at 90%, before subsiding to 70% towards the end of october  <cit> .
the latter months of the summer season certainly fall within this definition of the optimal climatic conditions for transmission.
during the winter season temperatures peak at about 28 °c and may fall as low as 7 °c at night and the mean humidity is usually in the range 75–86%.
these conditions are less suitable for survival of oocysts of t. gondii in the external environment.
thus, the tenacity and infectivity of oocysts in winter may be less than in summer, and hence transmission to cats and potential intermediate hosts such as rodents may be less efficient in winter months.
however, this requires further studies, for instance by environmental sampling for t. gondii oocysts and thorough assessment of the resilience of oocysts of local isolates of t. gondii to typical summer and winter conditions in qatar.
unfortunately, most people are unaware that they can acquire toxoplasmosis from the environment by direct contact with soil or water  <cit> .
CONCLUSIONS
the seroprevalence of t.gondii in cats in qatar is high.
our data showed that female cats were more likely to have high antibody responses compared with males, and that seroprevalence is higher in the summer months.
overall, our data imply high contamination of the local environment in qatar and we recommend further investigation of food/water sources through which transmission may occur.
we would like to thank the biomedical research center at qatar university and the cat control unit at the ministry of municipality and environment for providing facilities for this work.
funding
this publication was made possible by nprp grant number nprp 4-164-4- <dig> from qatar national research fund.
the contents of this report are solely the responsibility of the authors and do not necessarily represent the official views of qatar university and qrnf.
availability of data and materials
data will not be made available.
we were constrained by our local, internal ethics policies, which entail confidentiality with regard to the samples for analysis in studies of this nature.
we tried to put all the information needed for understanding the analysis and the subsequent results into the methods section.
authors’ contributions
sb carried out the serology and drafted the manuscript.
as collected the cat samples and contributed to the serology.
jmb carried out the statistical analysis and participated in the preparation and refinement of the manuscript.
mam conceived the study, collected the background information on the samples and revised the manuscript critically for important intellectual content.
all authors read and approved the final manuscript.
competing interests
the authors declare that they have no competing interests.
consent for publication
not applicable.
ethics approval
all applicable institutional and/or national guidelines for the care and use of animals were followed.
ethical approval for this project was obtained from qatar university institutional animal care and use committee .

 toxoplasmosis is a widespread zoonotic parasitic infection. it is estimated that about one third of the world population is chronically infected with toxoplasma gondii. felids are the only definitive hosts of the parasite and can shed millions of environmentally resistant oocysts in their feces if they become infected. the oocysts can remain infectious for more than 1 year in unfrozen and moist soil and can cause outbreaks of toxoplasmosis. this is evidenced by the large waterborne outbreak of toxoplasmosis in canada in that was epidemiologically linked to oocyst contamination of a water reservoir in british columbia. cats were introduced to qatar in the 1960s to control the high rodent population in the country, but subsequently they in turn reproduced rapidly. the current density of cats in qatar may pose a risk for humans, as cats are natural hosts for a wide range of zoonotic pathogens, including t. gondii. the overall seroprevalence of t. gondii among the qatari human population has been estimated at % with a progressive rise from <4% in the 1 year old group to % at >45 years of age. such observations provide further evidence for the increased risk of infection with increasing age through longer exposure time. as cats shed toxoplasma oocysts for only a short period of time after initial infection, detection of patent infections in cat populations is likely to underestimate the number of animals that have been exposed to infection. however, t. gondii elicits strong antibody responses in its hosts and therefore assessment of seroprevalence is an alternative approach for studying the epidemiology of this pathogen. estimates of antibody prevalence in the cat population also provide another useful indicator of environmental contamination. the current study is the first to estimate the seroprevalence of t. gondii in the feral cat population in qatar. methods sample collection feral cats were caught live as part of the routine activities of the qatar cat control unit as described previously. briefly, trapped adult cats that were eligible for the trap-neuter-return program were transported to a shelter for sterilization. for each animal the sex, the area, and the season of sampling were recorded. in the current study, sampling began in september and ended in september. cats from both urban and sub-urban areas were investigated in this study. within each sector, traps were set out in places most likely to be frequented by cats at night, i.e. in alleyways, in back yards close to houses, and near to rubbish bins and municipal garbage containers. blood was drawn by experienced veterinarians complying strictly with animal welfare guidelines as stipulated by the national institutional animal care and use committee of qatar. blood samples were then centrifuged at 5000 × g for 20 min at room temperature and the resulting supernatants were collected and used for serology. serology a total number of sera were tested for t. gondii igg antibodies using commercially available toxoplasma gondii antigen. two-fold serial dilutions, in phosphate buffered saline, were made from 1: to 1: and tested with a modified agglutination test, as previously described. samples that were positive at a dilution of 1: were further diluted in a second run to a dilution of 1: for antibody titration, and those positive at 1: were diluted in a third run until no further agglutination was evident. positive controls and negative controls were included in each test. agglutination in at least half of the “u” well bottoms of a microplate was accepted as a positive reaction. in the case of complete sedimentation on the well bottom with no sign of agglutination, the sample was recorded as negative, i.e. no evidence of t. gondii antibodies in the serum. a titer of or higher was considered positive. statistical analysis prevalence values are given with 95% confidence limits, calculated by bespoke software based on the tables of rohlf and sokal. for analysis of seroprevalence, we used maximum likelihood techniques based on log linear analysis of contingency tables in the software package ibm spss statistics version. initially, full factorial models were fitted, incorporating as factors sex, area and season. infection, reflecting the presence or absence of antibodies to t. gondii was coded as a binary factor, and the cut-off for statistical significance was considered to be a p value of. for analysis of quantitative data we first ranked the titers on a scale from to where 0 = no agglutination, 1 = maximum agglutination at 1: and so on to 8 = agglutination at dilutions higher than 1:. we used a zero-inflated model in r version. that analyzed a binomial process and a poisson for the rest.  of the feral cats tested, were positive for t. gondii antibodies. four samples presented prozone effects with negative results at the low dilution of 1: and positive agglutination at higher dilutions ≥ 1:. the frequency distribution of antibody titers among the sampled cats is shown in fig.  and the bimodal distribution of antibody titres, with peaks in the lower and top ends of the positive range can be clearly seen.fig. frequency distribution of antibody titres among the sampled cats. the figure shows the number of cats for which no antibody was detected and those that had detectable antibody. titres for the latter are given as the reciprocal of the maximum dilution at which agglutination was detected and these fall into two peaks. columns filled with stippled shading indicate the numbers of cats with titres in the lower intensity antibody range and those filled in black represent cats with the higher titres seroprevalence of t. gondii was similar in males and females: % and % respectively. with season and area taken into account, the difference between the sexes was not significant. however, when the prevalence of antibodies in male and female cats was plotted separately against serum dilution, there was a significant effect of host sex at high antibody titers.fig. the effect of host sex and season on the percentage of cat sera showing agglutination at varying dilutions of serum. percentage values are given with 95% confidence limits for each level of serum dilution. a effect of host sex. b effect of season. for statistical analysis see text seroprevalence was similar in cats from urban and sub-urban areas and no significant difference between areas was detected whether testing overall positivity, or positivity at specific dilutions of serum. the number of cats sampled in the summer was and in the winter months. there was a significant effect of season on seropositivity. seroprevalence was higher in the summer months in contrast to the winter. quantitative analysis was in general in agreement with these conclusions. based on the zero-inflated model and a binomial process in which the high responders were coded as and the rest as zero, the occurrence of the highest titers was affected significantly only by host sex. males had a lower frequency of high titers than females, as found in the earlier log linear model given above. discussion this study demonstrated a high overall seroprevalence of t. gondii antibodies in the feral cat population in qatar. seroprevalence was higher than values reported from neighboring countries, as for example % in kuwait and % in iraq. similar seroprevalences to those recorded in this study have been observed mainly among cats from tropical areas: ethiopia with % and the amazon with %. while the present work did not find an overall significant difference in seroprevalence between male and female cats as observed elsewhere, higher antibody titers were detected in female cats when analysis was restricted to the high dilutions which is in accordance with other reports. however our observation of some female cats expressing more intense antibody responses than male cats contrasts with the conclusions reached by miro et al., who reported in their study that stray male cats had significantly higher seroprevalence. the authors linked their findings to differences in the territorial habits of male and female cats, as male cats are more likely to wander and thus experience more access to contaminated sources. although ecological, social and epidemiological factors may account for some of the female biased antibody responses in our study, hormone-influenced immunological mechanisms have been proposed as the more likely mechanism underlying sex-biased parasitism with t. gondii. cat bioassays have not provided any clear evidence of sex-bias in the occurrence of toxoplasmosis. however, experimental studies in mice have shown that females are more susceptible than males to t. gondii infection and develop more severe cerebral inflammation. they are more likely to die following infection than males. female mice that survived the acute phase and developed chronic infections harbored more cysts in their brains than did surviving males. gonadectomy of female mice was shown to reduce the development of tissue cysts caused by t. gondii infection, whereas estrogen administration was found to exacerbate the infection. it remains unknown when the cats that tested positive had acquired the infection. the low intensity responses which were recorded in more than half of the cats in our study suggest antibodies from a past infection but may also include cats that have very recently been exposed to the parasite, and have not yet developed the maximum response. the cats that showed intense antibody responses are more likely to be cats that had acquired the infection recently but after a sufficient time to mount the response. since the prevalence of high intensity antibody responses was almost identical in both winter and summer months, this indicates that there is a persistent source of t. gondii infection in the environment in which the cats live. moreover, the consistently high seroprevalence in both urban and sub-urban areas of qatar suggests a high level of t. gondii contamination throughout the country. the large home ranges of feral cats, which can stretch to 10 km implies widespread contamination of the environment, especially given that some reports have documented cats travelling up to 45 km in just 2 days. domestic and stray/feral cats are the same species and the main difference between them is their lifestyle. in contrast to domestic animals, feral cats are unowned and live in the streets, alleys, farm buildings, factories, wharves or abandoned vehicles. they may be semi dependent on humans from whom they may receive some food. it has been reported elsewhere that % of cats fed table leftovers are toxoplasma seropositive with a majority showing high igg antibodies titers. these free-roaming cats are exposed to a wide variety of pathogens, and have been shown to be excellent sentinels of infectious and parasitic diseases. consequently they provide useful information on circulation of pathogens in domestic and wild ecosystems. most cats are thought to become infected with t. gondii after weaning when they begin to hunt for food. outdoor access facilitates hunting behavior, as in the netherlands where 93% of the cats with free outdoor access exhibited hunting behavior. stray cats and cats with outdoor access usually acquire the infection from hunting rather than from the ingestion of oocysts. hence the recommendation to pet owners that to protect their cats from t. gondii infection the hunting of small prey should be discouraged/prevented, and that all meat served to their pet cats should be thoroughly cooked and/or frozen before cooking. in a study conducted in italy, it was suggested that infected intermediate hosts that are prey for cats are more available in the summer season. a recent analysis reported a correlation between the geolatitude and humidity and occurrence of toxoplasmosis. the efficiency of transmission may therefore differ between seasons in qatar, with a higher risk of exposure in the summer months. qatar typically experiences two seasons. in the summer season, daytime temperatures frequently exceed 45 °c and seldom fall below 18 °c at night. humidity peaks in august at 90%, before subsiding to 70% towards the end of october. the latter months of the summer season certainly fall within this definition of the optimal climatic conditions for transmission. during the winter season temperatures peak at about 28 °c and may fall as low as 7 °c at night and the mean humidity is usually in the range 75–86%. these conditions are less suitable for survival of oocysts of t. gondii in the external environment. thus, the tenacity and infectivity of oocysts in winter may be less than in summer, and hence transmission to cats and potential intermediate hosts such as rodents may be less efficient in winter months. however, this requires further studies, for instance by environmental sampling for t. gondii oocysts and thorough assessment of the resilience of oocysts of local isolates of t. gondii to typical summer and winter conditions in qatar. unfortunately, most people are unaware that they can acquire toxoplasmosis from the environment by direct contact with soil or water.  the seroprevalence of t.gondii in cats in qatar is high. our data showed that female cats were more likely to have high antibody responses compared with males, and that seroprevalence is higher in the summer months. overall, our data imply high contamination of the local environment in qatar and we recommend further investigation of food/water sources through which transmission may occur. we would like to thank the biomedical research center at qatar university and the cat control unit at the ministry of municipality and environment for providing facilities for this work. funding this publication was made possible by nprp grant number nprp 4-164-4- from qatar national research fund. the contents of this report are solely the responsibility of the authors and do not necessarily represent the official views of qatar university and qrnf. availability of data and materials data will not be made available. we were constrained by our local, internal ethics policies, which entail confidentiality with regard to the samples for analysis in studies of this nature. we tried to put all the information needed for understanding the analysis and the subsequent results into the methods section. authors’ contributions sb carried out the serology and drafted the manuscript. as collected the cat samples and contributed to the serology. jmb carried out the statistical analysis and participated in the preparation and refinement of the manuscript. mam conceived the study, collected the background information on the samples and revised the manuscript critically for important intellectual content. all authors read and approved the final manuscript. competing interests the authors declare that they have no competing interests. consent for publication not applicable. ethics approval all applicable institutional and/or national guidelines for the care and use of animals were followed. ethical approval for this project was obtained from qatar university institutional animal care and use committee.
no significant difference was detected between seroprevalence in female and male cats and in cats from urban and suburban districts of qatar. cats are essential in the life cycle of toxoplasma gondii as they can shed the environmentally resistant oocysts after acquiring infection. the analysis revealed an overall seroprevalence of 82%. the current study is the first to estimate the seroprevalence of t. gondii in the feral cat population in qatar. we investigated the seroprevalence of t. gondii among adult cats from urban and suburban districts in qatar. despite the seasonal difference, the observed seroprevalence of t. gondii suggests high environmental contamination throughout the year, with some female cats generating more intense responses compared to males. using results from the modified agglutination test, we fitted statistical models with host sex, area and season as explanatory factors and seropositivity as the outcome. seroprevalence was significantly higher in the summer season. human populations living in cities with high densities of feral cats are therefore likely to be at risk of infection.
 cats are essential in the life cycle of toxoplasma gondii as they can shed the environmentally resistant oocysts after acquiring infection. human populations living in cities with high densities of feral cats are therefore likely to be at risk of infection. the current study is the first to estimate the seroprevalence of t. gondii in the feral cat population in qatar. we investigated the seroprevalence of t. gondii among adult cats from urban and suburban districts in qatar. using results from the modified agglutination test, we fitted statistical models with host sex, area and season as explanatory factors and seropositivity as the outcome.  the analysis revealed an overall seroprevalence of 82%. seroprevalence was significantly higher in the summer season. no significant difference was detected between seroprevalence in female and male cats and in cats from urban and suburban districts of qatar.  despite the seasonal difference, the observed seroprevalence of t. gondii suggests high environmental contamination throughout the year, with some female cats generating more intense responses compared to males. both findings merit further investigations. keywords serosurveyantibodiestoxoplasmosisfelidsmiddle eastseasonsexhttp://dx.doi.org/ /100008982qatar national research fundnprp 4-164-4-001abu-madi marawan issue-copyright-statement© the author 2017 