Toxoplasma gondii in sheep from the Campania region (Italy)

Comparison of Direct and Indirect Detection of Toxoplasma gondii in Ovine Using Real-Time PCR, Serological and Histological Techniques

Toxoplasma gondii is a zoonotic pathogen and the ingestion of tissue cysts by consumption of lamb or mutton has been identified as a possible cause of infection in humans. Many serological surveys in sheep have been performed, showing relevant serological rates; however, while the detection of antibodies indicates an exposure to T. gondii, this does not necessarily imply the presence of tissue cysts in edible tissue. The current study aims to provide further understanding on the occurrence of T. gondii in sheep muscles and the strength of correlation between serological positivity and presence of the parasite in sheep. From 349 sheep, samples (i.e., blood, heart and diaphragm) were collected and subjected to ELISA tests, real-time PCR and histological tests. Despite the high seroprevalence, T. gondii DNA was detected in the heart and/or the diaphragm from 13 out of the 349 tested sheep (3.7%); all were adults (13/191). Furthermore, the histological tests did not reveal the presence of T. gondii tissue cysts in any of the examined portions of interventricular septum. It should be considered that the likelihood of detecting genetic material of the parasite is probably influenced by the uneven distribution of the tissue cysts in the carcass as well as the methodology applied. The findings of this study support the importance of describing the uncertainty associated with the data used for risk assessment to reduce inaccurate estimation or risk overestimation.

Detection of Toxoplasma gondii Infection in Small Ruminants: Old Problems, and Current Solutions

Toxoplasmosis is a parasitic zoonosis of veterinary importance, with implications for public health. Toxoplasma gondii infection causes abortion or congenital disease in small ruminants. Moreover, the consumption of infected meat, cured meat products, or unpasteurized milk and dairy products can facilitate zoonotic transmission. Serological studies conducted in various European countries have shown the high seroprevalence of specific anti-T. gondii antibodies in sheep and goats related to the presence of oocysts in the environment, as well as climatic conditions. This article presents the current status of the detection possibilities for T. gondii infection in small ruminants and their milk. Serological testing is considered the most practical method for diagnosing toxoplasmosis; therefore, many studies have shown that recombinant antigens as single proteins, mixtures of various antigens, or chimeric proteins can be successfully used as an alternative to Toxoplasma lysate antigens (TLA). Several assays based on DNA amplification have been developed as alternative diagnostic methods, which are especially useful when serodiagnosis is not possible, e.g., the detection of intrauterine T. gondii infection when the fetus is not immunocompetent. These techniques employ multicopy sequences highly conserved among different strains of T. gondii in conventional, nested, competitive, and quantitative reverse transcriptase-PCR.

Molecular Survey of Toxoplasma gondii in Wild Mammals of Southern Italy

Systematic wildlife surveillance is important to aid the prevention of zoonotic infections that jeopardize human health and undermine biodiversity. Toxoplasma gondii is an opportunistic zoonotic protozoan that can infect all endothermic vertebrates, causing severe disease in immunocompromised humans and cases of congenital transmission. Humans can be infected by ingestion of raw meat containing bradyzoites or water contaminated by oocysts. In our study, we assessed the potential circulation of Toxoplasma gondii in wild mammals by performing surveillance in the Campania region (southern Italy) and surveyed its presence from 2020 to 2022 within the framework of the Regional Plans for Wildlife Surveillance. In detail, 211 individuals belonging to five wild mammals (wolf, fox, wild boar, badger, and roe deer) underwent necropsy and the organs were analyzed by real-time PCR for the detection of the parasite. Toxoplasma gondii was found in 21.8% (46/211) of the subjects examined. No statistically significant differences were noticed between the prevalence and the host’s trophic level or age, rejecting the hypotheses that Toxoplasma gondii will have a higher prevalence in top predators and adult individuals, respectively. Our work emphasized the high circulation of Toxoplasma gondii in wildlife and remarked on the critical role of anthropized areas where domestic cats and wildlife may come into contact, urging a systematic surveillance.

Seroprevalence and risk factors of Toxoplasma gondii infection in sheep in Algeria

Toxoplasma gondii infection is recognized as one of the major causes of reproductive failure in sheep and goats. This survey was carried out in order to study the seroprevalence of Toxoplasma infection in sheep in Blida, Bouira and Medea regions from Algeria. The sample size was set at 220 animals distributed over 22 farms. Sera were assayed for T. gondii antibody detection by Modified Agglutination Test (MAT). The overall seroprevalence was 35.9% (79/220) with a herd seroprevalence of 77.3% (17/22). The prevalence was significantly higher in Medea (45.7% of 116 sheep), compared to Blida (27.7% of 83 sheep). Bouira region showed the lowest prevalence with 3 positive samples (14.3%) over 21 sheep. Logistic regression analysis revealed that the likelihood of T. gondii infection was higher in semi-extensive sheep breeding, in regions where the presence of cats is strong, and in highlands when compared with semi-intensive sheep breeding, weak presence of cat and in lowland, respectively. This study shows a high seroprevalence of Toxoplasma infection in sheep in these areas.

Toxoplasma gondii infection in sheep from Romania

BACKGROUND

Toxoplasmosis is a widespread zoonosis caused by the intracellular protozoan parasite Toxoplasma gondii. Limited epidemiological information is available about the prevalence of T. gondii in sheep in Romania, and a high incidence would have implications for both the economy and public health. To our knowledge, no studies are available about the T. gondii strains circulating in lambs. The objective of this study was to assess the prevalence of T. gondii in sheep (serology), lambs (serology, bioassay, PCR) and sheep abortions (PCR) in Romania. Moreover, the study aimed to perform the genetic characterization of T. gondii isolates from lambs.

METHODS

Serum samples collected from 2650 sheep (2067 adults and 583 lambs) were tested for anti-T. gondii antibodies (IgG) using a commercial ELISA kit. Likewise, 328 pairs of diaphragmatic muscle-serum samples were collected from lambs aged between 2 and 4 months. Lamb serum samples were analyzed using MAT for anti-T. gondii antibody detection. The diaphragm tissue samples from MAT-positive lambs (at a dilution ≥ 1:25) were bioassayed in mice. The T. gondii strains were genotyped using 15 microsatellites markers. Additionally, brain and heart samples from 76 sheep abortions were analyzed for T. gondii DNA by polymerase chain reaction (PCR) targeting the 529-bp repeat region (REP529).

RESULTS

The results showed that more than half of the tested sheep were T. gondii seropositive (53.5%). The seroprevalence was significantly higher in adults (61.1%) than in lambs (26.4%). The seroprevalence of T. gondii infection in slaughtered lambs, by MAT, was 37.5% (123/328). There were bioassayed in mice 56 diaphragmatic tissues from 123 seropositive lambs. Toxoplasma gondii strains were isolated from 18 (32.1%) lambs intended for human consumption. All T. gondii strains were confirmed by PCR. Six strains were genotyped using 15 microsatellite markers and belonged to genotype II. Toxoplasma gondii DNA was detected in 11.8% (9/76) of sheep abortions.

CONCLUSIONS

The present study showed the presence of T. gondii in sheep in all the regions considered in the study. The high prevalence of T. gondii infection in sheep and lambs, demonstrated by serology, molecular analysis and bioassay, highlighted that there is an important risk of human infection in consuming raw or undercooked sheep/lamb meat.

Toxoplasma gondii in sheep: Serological occurrence at slaughterhouse level in Italy and environmental risk factors

Toxoplasmosis is a parasitic disease affecting a wide range of species, including humans, and can be responsible for important clinical manifestations such as abortion and neurological signs. Sheep show a remarkable susceptibility to its causative agent, Toxoplasma gondii, and zoonotic transmission may occur in case of consumption of undercooked meat obtained from infected animals. Toxoplasma gondii seroprevalence in sheep can significantly vary on a geographical basis, as shown by numerous surveys conducted worldwide. To investigate environmental and climate conditions that may affect the likelihood of ovine infection, 405 serum samples from selected sheep raised in 91 farms were collected from two abattoirs, with each abattoir receiving animals from two regions (1/Tuscany-Latium and 2/Campania-Basilicata). The seroprevalence of infection in all examined animals was 53.8%. Young animals (n = 165) had a lower likelihood of being T. gondii positive compared to the adults (OR = 0.21), and the seropositive rate of animals slaughtered in abattoir 2 was significantly higher than that of animals slaughtered in abattoir 1 (60.5 vs. 43.2%, p < 0.01). The significant bioclimatic variables (p < 0.05) associated with the presence of T. gondii antibodies were related to areas with a lower range of temperature and higher precipitation. In conclusion, this study expands on the interpretation of serological data, with the inclusion of environmental and climatic variables, as possible risk factors in the spread of toxoplasmosis in the study area. These findings provide novel insights to support public health measures, such as risk-based control plan, and contribute to a "One Health" approach, taking into account the environmental and climatic perspectives.

Use of PCR to determine Toxoplasma gondii in milk samples from camels (Camelus dromedarius), cattle (Bos taurus) and buffalos (Bubalus bubalis) in East Azarbaijan province, Iran

BACKGROUND

Toxoplasmosis as a zoonotic condition is developed by an intracellular protozoan parasite Toxoplasma gondii from the Apicomplexa phylum, which imposes economic losses on herds of animals and severe complications in immunocompromised people and pregnant women. This infectious disease can be transmitted to human beings from the contaminated unpasteurized milk, uncooked meat, water and food contaminated with sporulated oocysts and transplacental transmission.

OBJECTIVES

This study amid to determine T. gondii DNA in camel, buffalo and cow milks in using the PCR method based on the B1 gene.

METHODS

A total of 100 milk samples, including 55 cows, 30 buffalos and 15 camels, were collected from different regions of north-western using direct milking and then transferred to the Food and Aquatic Health Laboratory under refrigerated conditions.

RESULTS

The results showed that out of 100 milk samples examined, 5 samples (5%) were contaminated, and T. gondii DNA was detected in the milk samples of 2 (3.63%) cows, 1 (3.33%) buffalos and 2 (13.33%) camels, respectively.

CONCLUSIONS

Our findings reveal that raw milk contaminated with T. gondii can be an important route of transmission of infection for human beings.

Seroprevalence of Toxoplasma gondii infection in sheep and goats from different geographical regions of the world: Systematic review and meta-analysis

The Toxoplasma gondii is an obligate intracellular protozoan parasite which significantly impact small ruminant productivity, international animal trade and transboundary movement of animal across the globe. The seroprevalence of T. gondii infection (toxoplasmosis) in sheep and goats is widely studied in many parts of the world and there is a lack of comprehensive information on prevalence estimates considering the global and regional perspectives. The aim of the study was to use systematic review and meta-analysis methods to estimate the global and regional pooled seroprevalence of T. gondii infection in sheep and goats, as well as factors that influence prevalence estimations. Relevant articles reporting the seroprevalence of toxoplasmosis in sheep and/goats were searched in five electronic databases, including PubMed, Web of Science, Scopus, Embase and ProQuest. After the publications were checked to verify they fit the inclusion criteria, a total of 225 articles were included in the systematic review and meta-analysis, reflecting data from 70 countries/regions. The pooled prevalence was estimated using a random effect meta-analysis model. Overall, the seroprevalence of T. gondii infection was 33.86% (95% CI: 30.47-37.25%) in sheep and 31.78% (95% CI: 28.99-34.58%) in goats, with significant variation in prevalence estimates across geographical locations (p < .001). Substantial heterogeneity (I²  > 75%) was observed in most pooled seroprevalence estimates. The T. gondii infection in global sheep and goat population showed uptrend over the period. This information would be useful for epidemiologist, health authorities and farmers in order to plan future T. gondii survey and infection management strategies both locally and internationally.

A survey on Apicomplexa protozoa in sheep slaughtered for human consumption

Infections with the Apicomplexa Toxoplasma gondii, Neospora caninum, and Sarcocystis spp. are common causes of reproductive disorders in sheep. However, few epidemiological studies regarding co-infections with these three protozoa are reported in sheep in Italy. For this reason, this study aims to evaluate possible co-infections with T. gondii, N. caninum, and Sarcocystis spp. in sheep slaughtered for human consumption. From April to July 2019, individual blood, brain, heart, and diaphragm samples were collected from 138 sheep after slaughtering. The presence of IgG anti-Toxoplasma in serum samples was evaluated through ELISA. DNA of the three protozoa was investigated using specific PCRs. Co-infection with T. gondii, N. caninum and Sarcocystis spp. was found in 66.7% of the examined sheep. Antibodies against T. gondii were found in the 36.2% of serum samples. The presence of T. gondii DNA was detected in the 67.4%, 77.5%, and 21.7% of the brain, heart, and diaphragm samples, respectively. Neospora caninum DNA was found in 72.5% of the examined brain samples. Sarcocystis spp. DNA was detected in 92% and 52.2% of the heart and diaphragm samples, respectively. Sequence analysis of the Sarcocystis spp. revealed the sole presence of Sarcocystis tenella. The present study demonstrates that sheep have a high risk of infection with the three Apicomplexa investigated, suggesting the need to adopt adequate measures to prevent the spread of these parasitic infections considering their clinical and economic impact on ovine production. Furthermore, the possible role sheep play in the zoonotic transmission of toxoplasmosis to humans was highlighted.

Immunological, Histopathological, Molecular Identification and Genotyping of Toxoplasma gondii in Small Ruminants in Egypt

&lt;b&gt;Background and Objective:&lt;/b&gt; Toxoplasmosis is an infective zoonotic disease caused by protozoan &lt;i&gt;Toxoplasma gondii &lt;/i&gt;(&lt;i&gt;T. gondii&lt;/i&gt;).&lt;i&gt; &lt;/i&gt;Molecular identification of &lt;i&gt;T. gondii&lt;/i&gt; followed by studying the hereditary variety range of &lt;i&gt;T. gondii &lt;/i&gt;isolates in Egypt was investigated. &lt;b&gt;Materials and Methods:&lt;/b&gt; Blood samples were acquired from 138 live ewes and 212 she-goats from 5 governorates of Egypt, also the blood and its related tissue samples (uterus, diaphragm, heart and thigh muscles from each animal) were collected from slaughtered 180 ewes and 206 she-goats from Cairo and Giza abattoirs. &lt;b&gt;Results:&lt;/b&gt; Using ELISA, the total seropositivity of live ewes and she-goats was 26.8 and 21.2%, respectively, while it was 16.6 and 33% in slaughtered ewes and she-goats, respectively. &lt;i&gt;T. gondii&lt;/i&gt; tissue cysts with the associated characteristic histopathological changes were detected in different organs. Twenty-eight &lt;i&gt;T. gondii&lt;/i&gt; isolates were confirmed using PCR, while among 24 milk samples from seropositive live ewes and she-goats, only 12.5 and 6.25%, were positive using PCR, respectively. Genotyping using multiple nested PCR (n-PCR) combined with restriction enzyme analysis (RFLP) of the surface antigen 2 (SAG2) gene confirmed 26 isolates (92.8%) as type II and 2 (7.1%) as type III. &lt;b&gt;Conclusion:&lt;/b&gt; Type II and III are the most common &lt;i&gt;T. gondii&lt;/i&gt; genotypes in Egyptian small ruminants with additional importance for public health in Egypt. Further studies are needed on the role of milk in the transmission of toxoplasmosis.

Towards an Integrated Approach for Monitoring Toxoplasmosis in Southern Italy

Simple Summary

Toxoplasmosis is a significant public health issue worldwide, caused by the intracellular protozoan Toxoplasma gondii. It has a heteroxenous life cycle in which felines act as definitive reservoirs and a wide range of warm-blooded animals, including humans, act as intermediate hosts. Due to the complex life cycle, monitoring, prevention and control of this parasite are very difficult. A thorough analysis of the epidemiology of T. gondii in humans, animals and food as well as the risk factors associated with the infection are needed to plan adequate control strategies in a given geographical area. Based on this, an integrated approach for monitoring toxoplasmosis was developed and conducted in an endemic area of southern Italy. The main tasks of this approach were based on the following strategies: parasitological and risk factor analysis for T. gondii in livestock farms, serological and molecular monitoring in meat-producing livestock at slaughterhouses, hospital discharge records (HDRs) analysis and outreach activities. The findings of this study confirmed the spread of T. gondii infection in southern Italy with high prevalence values in ruminants and the need of valid control strategies based on comprehensive and transdisciplinary actions according to the One Health approach.

Abstract

Toxoplasmosis is a widespread worldwide zoonotic infection caused by the intracellular protozoan Toxoplasma gondii. This protozoan infection is considered one of the most important food-borne parasitic zoonoses globally. Beyond its impact on public health, toxoplasmosis has also important veterinary implications, because it causes miscarriage or congenital malformations in livestock with negative economic impacts. An integrated monitoring programme aimed to deepen the epidemiological data on toxoplasmosis and to identify the risk factors that may favour T. gondii infections in animals and humans was conducted in an endemic area of southern Italy. The monitoring activities were based on the following tasks: (i) parasitological analysis and risk factors for T. gondii in livestock (sheep, goat, cattle and water buffalo) farms; (ii) serological and molecular monitoring at slaughterhouse in meat-producing livestock; (iii) analysis of hospital discharge records (HDRs); (iv) outreach activities (information, dissemination and health education) to farmers, vet practitioners and school-age children. The present study confirmed a very high seroprevalence of T. gondii infection in livestock farms (e.g., up to 93.1% in sheep farms) in southern Italy and highlighted the potentially significant public health risk in this area.

Apicomplexan Protozoa Responsible for Reproductive Disorders: Occurrence of DNA in Blood and Milk of Donkeys (Equus asinus) and Minireview of the Related Literature

Donkeys may be susceptible to many pathological agents and may act as carriers of pathogens for other animal species and humans. This study evaluated the occurrence of potentially abortifacient apicomplexan protozoa DNA in blood and milk samples collected at different time periods during lactation (1, 6, and 10 months) from 33 healthy dairy jennies. A total of 73 blood and 73 milk samples were used for DNA extraction and analysis. Blood specimens from 11/33 (33%) jennies scored positive for Theileria equi, while milk samples scored negative. Blood and milk of 3/33 jennies yielded DNA of Toxoplasma gondii at 6 months (n. 1) and 10 months (n. 2) after parturition. Neospora caninum DNA was found in four milk and in five blood samples only at one month after parturition. This study is the first report about the presence of N. caninum DNA in milk of naturally infected jennies. Moreover, the excretion of N. caninum DNA in some of these jennies at 30 days from the parturition may suggest a possible occurrence of an endogenous cycle, while the presence of T. gondii DNA in the milk collected at 6 and 10 months after parturition may be suggestive of a discontinuous excretion.

Effect of Toxoplasma gondii on Ram Sperm Quality After Experimental Infection

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

Zoonotic risks of pathogens from sheep and their milk borne transmission

Sheep were domesticated around 9000 BC in the Middle East, and since then milk from sheep gradually became very popular, not only for drinking but also for making cheeses and other dairy products. Nowadays, these dairy products are also important for people with an allergy to cow milk, and these products are an essential part of the local daily diet in regions of the world that are not suitable for cows and goats. Consumption of raw milk and raw milk products has a zoonotic risk, and with regard to sheep, the main pathogens associated with such dairy products are: Brucella melitensis, Campylobacter spp., Listeria spp., Salmonella spp., Shiga-toxin producing Escherichia coli, Staphylococcus aureus, tick borne encephalitis virus, and Toxoplasma gondii. Especially, young children, elderly people, pregnant women and immunocompromised (YOPI) persons, and those suffering from disease should be aware of the risk of consuming raw milk and raw milk products. This latter risk can be reduced by proper flock health management, prevention of contamination during milking, adequate milk processing, transport, and refrigerated storage. Only processes equaling pasteurization sufficiently reduce zoonotic risks from milk and milk products, but proper cooling is essential and recontamination must be prevented. Therefore, strict hygiene practices throughout the production process and supply chain especially for raw milk and raw dairy products, should be applied. Small scale production systems pose a greater risk compared to industrialized production systems because of a less protocolized and controlled production process. This manuscript describes zoonotic risks of pathogens from sheep and their milk borne transmission. Additionally, routes of contamination, possibilities for multiplication, and prevention measures thereof are described. We summarize some major human outbreaks caused by consumption of sheep milk and products made thereof, and finally discuss their implications.

Economic and public health importance of Toxoplasma gondii infections in sheep: 2009-2020

Toxoplasma gondii infections are common in humans and animals worldwide. The present review summarizes worldwide information on the prevalence of clinical and subclinical infections, epidemiology, diagnosis, control, and genetic diversity of T. gondii in sheep in the past decade. There is debate and uncertainty concerning repeat congenital infection as evidenced by finding T. gondii DNA in progeny of chronically infected sheep. However, there is no concrete evidence that T. gondii is the cause of repeated abortions in sheep. Recent data concerning pathogenesis of abortion in acutely infected sheep are reviewed. PCR-RFLP typing of T. gondii DNA derived from viable T. gondii isolates or tissues of infected sheep revealed low genetic diversity in sheep in Europe, Africa, Asia and North America but high diversity in South America. This review will be of interest to biologists, parasitologists, veterinarians, and public health workers.

Large-Scale Epidemiological Study on Toxoplasma gondii Seroprevalence and Risk Factors in Sheep in Estonia: Age, Farm Location, and Breed Associated with Seropositivity

Toxoplasma gondii is a zoonotic parasite of major veterinary and public health importance. The parasite is common in many host species in Estonia, however, information about the seroprevalence in the local sheep population is lacking. We estimated T. gondii seroprevalence and evaluated a limited selection of possible risk factors for T. gondii seropositivity in sheep raised in Estonia. Sera from 1599 sheep from 122 flocks, collected during 2012-2013, were diluted to 1:40 and screened for the presence of anti-T. gondii immunoglobulin G antibodies using a commercial direct agglutination test. The cutoff titer for seropositivity was 40. A total of 667 of the 1599 sheep were T. gondii seropositive, yielding an apparent seroprevalence estimate of 41.71% (95% confidence interval 39.31-44.14). At least one seropositive sheep was detected on the majority (88.53%) of the farms. T. gondii seroprevalence was significantly lower in lambs (age <12 months) than in adults (age ≥12 months) (11.11% and 42.16%, respectively). The seroprevalence increased steeply with age in the first years of life. A multivariable random-effects logistic regression model identified being an adult (odds ratio [OR] 9.55) and being from a farm located on the islands (OR 2.51) as risk factors for T. gondii seropositivity, while being of Texel breed appeared as a protective factor (OR 0.34) when compared with the Estonian Blackhead breed. Exposure to T. gondii was widespread among the investigated sheep. Undercooked meat and unpasteurized milk from sheep from Estonia should be considered possible sources of T. gondii infections to other hosts, including humans.

Toxoplasma gondii Antibodies in Bulk Tank Milk Samples of Caprine Dairy Herds

A major public health issue, Toxoplasma gondii infection can affect humans mainly via the consumption of animal products from certain species, including small ruminants. Therefore, a regular monitoring of the infection in ovine and caprine populations is advisable for the control of human and animal toxoplasmosis. Antibody detection in individual and bulk tank milk (BTM) may represent a valid alternative to serological analysis, in that its collection is easy and does not affect animal welfare. Many serological tools for milk analysis have already been validated for several parasites, including Apicomplexa. Thus, the aim of the present study was to obtain epidemiological data on T. gondii infection through the detection of antibodies in BTM of dairy goat herds from an important area for caprine dairy production (northern Italy). The performance of a commercial ELISA was first evaluated for analysis of caprine milk samples, using a panel of serum-milk pairs of goats naturally infected by T. gondii. The analysis of BTM confirmed the presence of anti- T. gondii antibodies in 59% of the samples. Toxoplasma gondii antibody positivity was more frequently found in goats reared on farms under extensive (64.9%) or semi-intensive systems (68.7%) in comparison with intensive farms (51.1%). Analysis of milk was a valid alternative to serological tests, being easily applied in large-scale epidemiological surveys and for continuous monitoring of T. gondii infection.

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

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

Prevalence and Risk Factors for Toxoplasmosis in Middle Java, Indonesia

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii. Risk factors include consumption of undercooked meat, raw vegetables, and unfiltered water. This study aims to determine the seroprevalence and spatial distribution of toxoplasmosis in Middle Java, Indonesia, using an EcoHealth approach, combined with geographic information system (GIS). A total of 630 participants were randomly selected from seven districts. Each participant completed a questionnaire and provided a blood sample. The seroprevalence of toxoplasmosis was 62.5%. Of those who were seropositive, 90.1% were IgG+, and 9.9% were IgG+ and IgM+. Several risk factors were identified, including living at elevations of ≤200 m, compared with >200 m (OR = 56.2; P < 0.001), daily contact with raw meat (OR = 1.8; P = 0.001), unfiltered water (OR = 1.7; P = 0.003), and density of cats (OR = 1.4; P = 0.045). Visualizing the spatial distribution of seropositive respondents highlighted clustering in lowland areas. This study highlighted that Middle Java has a high prevalence of toxoplasmosis and identified some important environmental, ecological, and demographic risk factors. When researching diseases, such as toxoplasmosis, where animal hosts, human lifestyle, and environmental factors are involved in transmission, an EcoHealth method is essential to ensure a fully collaborative approach to developing interventions to reduce the risk of transmission in high-risk populations.

Toxoplasma Gondii and Pre-treatment Protocols for Polymerase Chain Reaction Analysis of Milk Samples: A Field Trial in Sheep from Southern Italy

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii. Ingestion of raw milk has been suggested as a risk for transmission to humans. Here the authors evaluated pre-treatment protocols for DNA extraction on T. gondii tachyzoite-spiked sheep milk with the aim of identifying the method that resulted in the most rapid and reliable polymerase chain reaction (PCR) positivity. This protocol was then used to analyse milk samples from sheep of three different farms in Southern Italy, including real time PCR for DNA quantification and PCR-restriction fragment length polymorphism for genotyping. The pre-treatment protocol using ethylenediaminetetraacetic acid and Tris-HCl to remove casein gave the best results in the least amount of time compared to the others on spiked milk samples. One sample of 21 collected from sheep farms was positive on one-step PCR, real time PCR and resulted in a Type I genotype at one locus (SAG3). Milk usually contains a low number of tachyzoites and this could be a limiting factor for molecular identification. Our preliminary data has evaluated a rapid, cost-effective and sensitive protocol to treat milk before DNA extraction. The results of the present study also confirm the possibility of T. gondii transmission through consumption of raw milk and its unpasteurised derivatives.

MIC16 gene represents a potential novel genetic marker for population genetic studies of Toxoplasma gondii

Background

The zoonotic agent Toxoplasma gondii is distributed world-wide, and can infect a broad range of hosts including humans. Microneme protein 16 of T. gondii (TgMIC16) is responsible for binding to aldolase, and is associated with rhomboid cleavage and presence of trafficking signals during invasion. However, little is known of the TgMIC16 sequence diversity among T. gondii isolates from different hosts and geographical locations.

Results

In this study, we examined sequence variation in MIC16 gene among T. gondii isolates from different hosts and geographical regions. The entire genomic region of the MIC16 gene was amplified and sequenced, and phylogenetic relationship was reconstructed using Bayesian inference (BI) and maximum parsimony (MP) based on the MIC16 gene sequences. The results of sequence alignments showed two lengths of the sequence of MIC16 gene among all the examined 12 T. gondii strains: 4391 bp for strains TgCatBr5 and MAS, and 4394 bp for strains RH, TgPLH, GT1, PRU, QHO, PTG, PYS, GJS, CTG and TgToucan. Their A+T content ranged from 50.30 to 50.59 %. A total of 107 variable nucleotide positions (0.1–0.9 %) were identified, including 29 variations in 10 exons and 78 variations in 9 introns. Phylogenetic analysis of MIC16 sequences showed that typical genotypes (Type I, II and III) were able to be grouped into their respective genotypes. Moreover, the three major clonal lineages (Type I, II and III) can be differentiated by PCR-RFLP using restriction enzyme Pst I.

Conclusions

Phylogenetic analysis and PCR-RFLP of the MIC16 locus among T. gondii isolates from different hosts and geographical regions allowed the differentiation of three major clonal lineages (Type I, II and III) into their respective genotypes, suggesting that MIC16 gene may provide a novel potential genetic marker for population genetic studies of T. gondii isolates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-016-0726-3) contains supplementary material, which is available to authorized users.

Prevalence and risk factors for Toxoplasma gondii infection in meat animals and meat products destined for human consumption

Toxoplasma gondii is a protozoan parasite that is responsible for approximately 24% of all estimated deaths attributed to foodborne pathogens in the United States. Human infection results from accidental ingestion of oocysts from the environment, in water, or on insufficiently washed produce or from consumption of raw or undercooked meat products that contain T. gondii tissue cysts. This review focused on studies of T. gondii in meat because many human T. gondii infections are acquired through consumption of raw or undercooked meat. Prevalence of T. gondii is higher in conventionally reared pigs, sheep, and poultry than in cattle and is greater in meat products from organic than from conventionally reared meat animals because of outdoor access, which poses substantially greater opportunities for exposure to infected rodents, wildlife, and oocyst-contaminated feed, water, or environmental surfaces. Risk factors related to T. gondii exposure for livestock include farm type, feed source, presence of cats, methods of rodent and bird control, methods of carcass handling, and water quality. This review serves as a useful resource and information repository for informing quantitative risk assessment studies for T. gondii infection in humans through meat consumption.

Seroprevalence and risk factors of Toxoplasma gondii and Neospora caninum infections in small ruminants in China

Little information is available about the seroprevalence of Toxoplasma gondii and Neospora caninum infections in sheep and goats in China. In the present investigation, the seroprevalence of T. gondii and N. caninum infections in sheep and goats were investigated in Qinghai province, China between January 2012 and June 2013. A total of 1250 serum samples (600 sheep and 650 goats) collected from 8 administrative regions of Qinghai province, China were evaluated by enzyme-linked immunosorbent assay for the detection of specific antibodies, and sera positive were subsequently confirmed with indirect fluorescent antibody test. Specific IgG against T. gondii were detected in 21.33% (95% confidence interval [CI]: 18.06-24.61%) (128/600) and 29.54% (95% CI: 26.03-33.05%) (192/650) and against N. caninum in 10.33% (95% CI: 7.9-12.77%) (62/600) and 7.23% (95% CI: 5.24-9.22%) (47/650) of the sheep and goats, respectively. The risk factors significantly associated with T. gondii and N. caninum seroprevalence were the presence of cats and dogs, the pasturing system, the herd size, the hygiene in the farms. The results of the present survey indicate that T. gondii and N. caninum infections are highly prevalent in sheep and goats in Qinghai province, China. This is the first time that antibodies to N. caninum have been detected in sheep and goats in China.

Animals are key to human toxoplasmosis

Toxoplasma gondii is an extremely sucessfull protozoal parasite which infects almost all mamalian species including humans. Approximately 30% of the human population worldwide is chronically infected with T. gondii. In general, human infection is asymptomatic but the parasite may induce severe disease in fetuses and immunocompromised patients. In addition, T. gondii may cause sight-threatening posterior uveitis in immunocompetent patients. Apart from few exceptions, humans acquire T. gondii from animals. Both, the oral uptake of T. gondii oocysts released by specific hosts, i.e. felidae, and of cysts persisting in muscle cells of animals result in human toxoplasmosis. In the present review, we discuss recent new data on the cell biology of T. gondii and parasite diversity in animals. In addition, we focus on the impact of these various parasite strains and their different virulence on the clinical outcome of human congenital toxoplasmosis and T. gondii uveitis.

Seroprevalence and risk factors associated with ovine toxoplasmosis in Northeast Brazil

Serum samples of 930 sheep were tested by ELISA to assess the prevalence of anti-Toxoplasma gondii antibodies and to identify risk factors associated with the presence of toxoplasmosis in two regions of Rio Grande do Norte (Northeast Brazil), with different climatic conditions. The overall estimated prevalence was 22.1%, with 26.3% and 17.8% positive sheep in Leste Potiguar and Central Potiguar regions, respectively. Among the positive sheep, 18.1% had low-avidity IgG antibodies, suggesting the occurrence of recent toxoplasmosis. The risk factors for toxoplasmosis in sheep were: presence of cats (odds ratio (OR) = 1.55; confidence interval (CI) 95% = 1.11-2.16), age of the animals, with adults presenting a greater chance of infection (OR = 2.44; CI 95% = 1.58-3.75), and the use of running water (OR = 1.61; CI 95% = 1.25-2.09), characterizing the existence of transmission by sporulated oocysts of T. gondii in the environment.

Seroprevalence and risk factors for Toxoplasma gondii in sheep in Grosseto district, Tuscany, Italy

Background

Serum samples from 630 milk sheep, in 33 dairy flocks representative of the southern area of the Tuscany region, were tested for the presence of antibodies to Toxoplasma gondii using an indirect immunofluorescence antibody test (IFAT). Questionnaires exploring the management system were completed by the veterinarian in charge of the flocks.

Results

At least one seropositive animal was found in 32 of the 33 flocks tested (97.0%; 95% CI: 84.2%, 99.9%). In the positive flocks, median seroprevalence was 29.4% (interquartile range: 15.9%-46.1%). Overall animal-level seroprevalence, adjusted for sampling weights and test sensitivity and specificity, was 33.3% (95% CI: 24.8%, 42.7%). In a multivariable negative binomial regression model the number of seropositive animals in a flock decreased with increasing flock size (for >400 vs. <300 animals: count ratio (CR) = 0.62; 95% CI: 0.41, 0.95; P = 0.028) and was greater on farms where stray cats had access to animals’ water (CR = 1.54; 95% CI: 1.05, 2.26; P = 0.027).

Conclusions

Small flock size and access of cats to water are potential risk factors for Toxoplasma infection in sheep in the Grosseto district in Tuscany, Italy. Sheep could be an important source of T. gondii infection in humans, since we estimate that between 25% and 43% of sheep in the district were seropositive. Toxoplasmosis is also likely to be an important cause of abortion in sheep in the district. Control and prophylactic measures must be adopted to improve the rearing system and the implementation of health promoting programmes in a joint effort between sheep farmers, farmers’ associations and veterinarians to inform about the means of transmission of the infection and for a better understanding of the disease.

Soroepidemiologia da toxoplasmose em caprinos e ovinos de três municípios do estado do Rio de Janeiro

A toxoplasmose é uma zoonose de ampla distribuição mundial, causada pelo Toxoplasma gondii. O estudo da prevalência desta infecção em animais produtores de carne e leite é de interesse à saúde pública, devido ao fato desses produtos oriundos de animais infectados serem importantes vias de transmissão para o homem, quando consumidos in natura. Além disso, há o aspecto econômico, uma vez que pode causar aborto, retardo no crescimento e animais debilitados, levando prejuízos ao pecuarista. Este trabalho objetivou estimar a soroprevalência da infecção por T. gondii, por meio da reação de imunofluorescência indireta (RIFI) em caprinos e ovinos de três municípios do estado do Rio de Janeiro, provenientes de 10 propriedades. A prevalência de anticorpos IgG anti-T.gondii foi de 29,12% (60/206) nos caprinos e de 38,05% (137/360) nos ovinos, sendo observada nessa última espécie associação (p<0,05) entre sexo (fêmeas), idade adulta, sistema de criação extensivo, dieta de pastagem e água de beber de açude com a soropositividade. Os títulos variaram de 64 a 256, podendo ser sugestivos de infecção crônica. Melhorias nas técnicas de criação podem reduzir as fontes de infecção por T. gondii nos rebanhos.

Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes

Toxoplasmosis is the major parasitic disease affecting sheep. It is important for veterinary medicine, animal science and public health since it causes reproductive and economic losses in the herd, as well as damaging human health due to consumption of contaminated meat and milk, which can facilitate zoonotic transmission. Detection of Toxoplasma gondii in ovine milk and lack of data in the literature describing differentiation between acute and chronic disease for this species stimulated the elaboration of the present research project. To achieve the aim of this study, the animals were allocated to two groups of 20 ewes each, of which group 1 was composed of animals with positive serology and group 2 with negative serology. Acute and chronic stages of the disease were differentiated by modified direct agglutination test (MAT), in which antigens were fixed with formalin (MAT-AF) and methanol (MAT-AM). The parasite was detected in milk by polymerase chain reaction (PCR), and the molecular identity of the amplified products was confirmed by sequencing. The serological results indicated that sheep had a chronic infection profile. T. gondii DNA was detected in seven milk samples from five seropositive sheep, and twice in milk of two sheep. Sequences of species shared 97-100% identity with T. gondii. These findings allowed the hypothesis that the peripartum period may also lead to the resurgence of tissue T. gondii tachyzoites cysts which can circulate again and be excreted in the milk. This study used sheep naturally infected with T. gondii as a prerequisite for further investigations on the possible participation of this species in toxoplasmosis epidemiology and as a potential transmission route related to consumption of milk from infected sheep.

Mic1-3 Knockout Toxoplasma gondii is a good candidate for a vaccine against T. gondii-induced abortion in sheep

This study assessed the effectiveness of a mutant strain of Toxoplasma gondii (RH strain) lacking the mic1 and mic3 genes (Mic1-3KO) against Toxoplasma abortion in sheep. Ewes were inoculated subcutaneously with 10⁵ Mic1-3KO tachyzoïtes in three independent experiments. Following vaccination, Mic1-3KO induced a mild febrile response and serum IgG antibodies, which persisted throughout the experiments. Tissue cysts formed in the sheep, but were not, under our experimental conditions, infectious when given orally. Ewes were mated two months after vaccination and were orally challenged with the PRU strain of T. gondii at mid-gestation (400 oocysts in Experiments 1 and 2; 100 oocysts in Experiment 3). Challenge of vaccinated pregnant ewes resulted in a slight febrile response, whereas unvaccinated ewes developed a more severe, characteristic febrile response of longer duration. After challenge, all unvaccinated ewes aborted whereas 62%, 91% and 64% (Experiments 1, 2 and 3 respectively) of the lambs from vaccinated ewes were viable, with no clinical signs of infection. Mic1-3KO was as effective as S48, the strain used as a live vaccine for sheep (Toxovax^®). A dose of 10⁵ Mic1-3KO tachyzoites was sufficient to induce protection (versus a dose of 2 × 10⁶). Both subcutaneous and intraperitoneal injections were effective. Moreover, preliminary results showed the potential of Mic1-3KO to reduce the development of tissue cysts in lambs born to vaccinated ewes. This study demonstrates that Mic1-3KO is a potent vaccine candidate.

Structural insights into microneme protein assembly reveal a new mode of EGF domain recognition

The obligate intracellular parasite Toxoplasma gondii, a member of the phylum Apicomplexa that includes Plasmodium spp., is one of the most widespread parasites and the causative agent of toxoplasmosis. Adhesive complexes composed of microneme proteins (MICs) are secreted onto the parasite surface from intracellular stores and fulfil crucial roles in host-cell recognition, attachment and penetration. Here, we report the high-resolution solution structure of a complex between two crucial MICs, TgMIC6 and TgMIC1. Furthermore, we identify two analogous interaction sites within separate epidermal growth factor-like (EGF) domains of TgMIC6-EGF2 and EGF3-and confirm that both interactions are functional for the recognition of host cell receptor in the parasite, using immunofluorescence and invasion assays. The nature of this new mode of recognition of the EGF domain and its abundance in apicomplexan surface proteins suggest a more generalized means of constructing functional assemblies by using EGF domains with highly specific receptor-binding properties.

Control of the risk of human toxoplasmosis transmitted by meat

One-third of the human world population is infected with the protozoan parasite Toxoplasma gondii. Recent calculations of the disease burden of toxoplasmosis rank this foodborne disease at the same level as salmonellosis or campylobacteriosis. The high disease burden in combination with disappointing results of the currently available treatment options have led to a plea for more effective prevention. In this review we describe Toxoplasma as a hazard associated with the consumption of undercooked meat or meat products and provide an analysis of the various options to control the risk of human toxoplasmosis via this source. Monitoring and surveillance programs may be implemented for pre-harvest control of Toxoplasma infection of farm animals, with the reduction of environmental oocyst load as the most important milestone. Alternatively, Toxoplasma safe meat can be obtained through simple post-harvest decontamination procedures, whereby freezing the meat may currently be the best option, although new technologies using irradiation or high-pressure treatment may offer promising alternatives. Influence of culture, religion and food handling customs may predispose a certain type of meat as an important source of infection, indicating that prevention needs to be tailored according to social habits in different regions in the world. The rationale for more stringent control measures to prevent toxoplasmosis both from disease and economic points of view is emphasized.