**3. Epizootiology of toxoplasmosis in SEE**

Epizootiological surveillance of *T. gondii* infection in meat animals is important both as a measure essential for animal health and economics of livestock production, and for assessment of the risk for human health, as infected meat animals represent an important reservoir for human infection.

Throughout SEE, few data are available on *T. gondii* infection in animals and most are not the result of systematic research. Early reports, in particular from Serbia/Yu, dealt with isolation of viable *T. gondii* from various species. By bioassay of brains and/or hearts in ground squirrels (*Spermophilus citellus*) *T. gondii* was isolated from 0.25% chickens (Simitch et al., 1961); and 0.7% pigs, 0% sheep and cattle, 6.2% guinea fowl, 3.8% turkeys, 3.6% ducks, 1% geese and 0% pigeons (Simić et al., 1967). By mouse bioassay, *T. gondii* has been isolated from pork, and from pig and sheep diaphragms in Croatia/Yu (Wikerhauser et al., 1983; 1988). In Bosnia/Yu, Živković and Arežina (1991) reported apparent *T. gondii* in smears from muscle tissues of farmed layers.

The data on strain isolation in animals are scarce; researchers in Bulgaria have reported isolation of both virulent and avirulent strains of *T. gondii* from domestic and wild animals, but did not perform genetic typing (Arnaudov, 1978; Arnaudov et al., 2003; Arnaudov & Arnaudov, 2005). In Serbia, genotyping of *T. gondii* strains isolated from animals (sheep, pigs, pigeons) is in progress, and the first results confirm the dominance of type II strains (unpublished data).

42 Toxoplasmosis – Recent Advances

patients too.

reservoir for human infection.

muscle tissues of farmed layers.

infection across the region currently complicates the choice of prevention strategy. A decrease in the prevalence of infection in women of childbearing age implies a rising proportion of women susceptible to infection in pregnancy, which, in turn, may lead to an increase in the incidence of congenital infections. Indeed, an increase in the incidence of primary infections in pregnancy has been shown through systematic screening-in-pregnancy programs; in Austria, which has been screening all pregnant women ever since 1975, the decrease in *T. gondii* prevalence from 50% to 37% during the 1980s was followed by an increase in the incidence of primary infections in pregnancy from 0.4% to 0.8% (Aspöck & Pollak, 1992). Similarly, in Slovenia, the decrease in the prevalence of infection from the early 1980s onwards, therefore before the introduction of the systematic prevention program in 1995, has been associated with an increased incidence of infections in pregnancy from 0.33% in the early 1980s to 0.75% in the early 1990s and to 0.94% in the late 1990s (Logar et al., 1995; 2002). The decreasing prevalence of *T. gondii* infection and a possible subsequent increase in the incidence of primary infections in pregnancy warrants introduction of CT prevention programs in the SEE countries. A prerequisite for such programs to be cost-effective, however, is an accurate assessment of the proportion of women of childbearing age susceptible to infection in pregnancy and the subsequent incidence of CT. These data are not yet available for most of the SEE, and are further complicated by the changing pattern of infection across the region. Thus, a sound and financially sustainable alternative that may be recommended for all of the SEE, similar to what has been recommended for Serbia (Bobić et al., 2003), includes health education of all women of childbearing age focusing on the locally

significant risk factors for infection transmission in particular countries.

**3. Epizootiology of toxoplasmosis in SEE** 

Health education is an adequate preventive measure for uninfected immunocompromised

Epizootiological surveillance of *T. gondii* infection in meat animals is important both as a measure essential for animal health and economics of livestock production, and for assessment of the risk for human health, as infected meat animals represent an important

Throughout SEE, few data are available on *T. gondii* infection in animals and most are not the result of systematic research. Early reports, in particular from Serbia/Yu, dealt with isolation of viable *T. gondii* from various species. By bioassay of brains and/or hearts in ground squirrels (*Spermophilus citellus*) *T. gondii* was isolated from 0.25% chickens (Simitch et al., 1961); and 0.7% pigs, 0% sheep and cattle, 6.2% guinea fowl, 3.8% turkeys, 3.6% ducks, 1% geese and 0% pigeons (Simić et al., 1967). By mouse bioassay, *T. gondii* has been isolated from pork, and from pig and sheep diaphragms in Croatia/Yu (Wikerhauser et al., 1983; 1988). In Bosnia/Yu, Živković and Arežina (1991) reported apparent *T. gondii* in smears from

The data on strain isolation in animals are scarce; researchers in Bulgaria have reported isolation of both virulent and avirulent strains of *T. gondii* from domestic and wild animals, Earlier serological investigations of various animal species in SEE countries showed a prevalence of 37% for cattle, 30% for sheep, 26% for pigs, 17% for horses, 41% for dogs, 25% for cats, 52% for house mice and 20% for rats in Serbia, but except for pigs, they were carried out on samples of limited size (Šibalić, 1977). In Bulgaria, Nankov (1968) has shown a 15.7% prevalence in hares, and Arnaudov (1971, 1973) reported a prevalence of 32.6% for sheep and 27.2% for goats.

An overview of studies of *T. gondii* infection in animals in SEE countries in the last 20 years is presented in Table 2. Evidently, data are not available for a half of the SEE countries.

As in humans, and similar to the rest of Europe and elsewhere (Tenter et al., 2000; Hall et al., 2001), data on the prevalence in animals vary quite widely in SEE. The highest prevalence has been reported for cattle, sheep and goats (Table 2). While farming practices are similar throughout the SEE region, differences within the region mostly occur in the climatic conditions and terrain characteristics.

The single nation-wide survey on *T. gondii* infection in meat animals in SEE, performed recently in Serbia, showed high seroprevalence rates of 76.3% in cattle and 84.5% in sheep and a lower one, of 28.9%, in pigs (Klun et al., 2006). This study showed that cattle from Western Serbia were at an increased risk of infection compared to all other regions (Table 3), possibly associated with a comparably increased humidity in this region (Klun et al., 2006). The levels of specific antibody determined in the cattle were relatively low (not above 1:400),



*Toxoplasma gondii* Infection in South-East Europe: Epidemiology and Epizootiology 45

which is consistent with reports on the rapid decrease of *T. gondii* antibody in cattle (Dubey et al., 1985). Cattle are relatively resistant to *T. gondii* infection (Dubey and Thulliez, 1993), but it is unclear whether this is associated with fast elimination of cysts from cattle tissues (Dubey, 1983), or there is inconsistent cyst formation following infection. In addition to farm location in the western region, the only other risk factor determined for cattle infection was small herd size. According to the type of housing, the results showed that access to outside pens was protective as compared to total confinement. This apparently paradoxical finding may represent a further argument for the importance of the way in which feed is kept, or possibly indicates involvement of other farm factors not identified in this type of study.

The same study showed a prevalence of 85% in sheep in Serbia, of which 10% had high antibody levels of ≥1:1600, suggestive of acute infection. Although arbitrary, the cut-off of 1:1600 is even conservative since Dubey and Welcome (1988) had considered a titre of 1:1024 high. However, correlation with ovine abortions could not be established, since etiological laboratory diagnosis of ovine abortions in Serbia does not include diagnosis of *T. gondii*. Regionwise, similarly as with cattle, sheep from Western Serbia were at an increased risk of infection as compared to all other regions (Table 3). An increased risk of infection was also found in state-owned vs. private large flocks. Compared to other SEE countries, the prevalence of 85% is quite high; in Croatia and Bulgaria the highest recorded prevalence in sheep is 48%, and in Greece 58.5% (Table 2). This is also evident in goats; compared with the prevalence of 74.7% established in Serbia (Djokić et al., 2011), it was lower in Greece (62.9%) (Diakou et al., 2005b) and Bulgaria (59.8%) (Prelezov et al., 2008), and very markedly so in

An outbreak of toxoplasmosis in sheep has recently been reported; massive abortions (60%) occurred in a flock of 500 dairy sheep in Northern Greece at 110-130 days of pregnancy, diagnosed upon observation of tissue cysts in brain smears of aborted fetuses, and by serological (ELISA) examinations of mother and fetal serum samples. The abortion rate

In horses, who generally have lower seroprevalence values than small ruminants (van Knapen et al., 1982), a prevalence of 30.8% has been determined in a study in Serbia (Klun,

In pigs, an overall seroprevalence of 29% was established in Serbia (Klun et al., 2006). Of those seropositive, 4% were likely to be in the acute stage of infection, indicating continuous presence of infection reservoirs in the environment. Risk factors included age and farm type (Table 3). Since pigs are continuously exposed to infection, the increase in the risk of infection with age, ranging from 15% in market weight age pigs to 41% in adults, was expected, and repeated previous findings (Dubey et al., 1991; Dubey et al., 1995; Weigel et al., 1995; Damriyasa et al., 2004). Pigs on finishing type farms were four-fold more likely to be infected than those from farrow-to-finish farms. According to these results, it was proposed that a national strategy to reduce the level of *T. gondii* infection in pigs should include a shift towards the development of more farrow-to-finish farms, as well as vigilance in farm management and implementation of zoo-hygienic measures at finishing farms. Damriyasa et al. (2004)

stated that *T. gondii* seropositivity is an indicator of the hygienic status of the pig farm.

declined immediately upon instituting sulfadimidine therapy (Giadinis et al., 2011).

Croatia – 8.4% (Rajković-Janje et al., 1993).

2005), *vs.* only 1.7% in Greece (Kouam et al., 2010).

(a) Mean ODnegative controls + 3SD

**Table 2.** *Toxoplasma gondii* infection in animals in SEE countries in the last 20 years

which is consistent with reports on the rapid decrease of *T. gondii* antibody in cattle (Dubey et al., 1985). Cattle are relatively resistant to *T. gondii* infection (Dubey and Thulliez, 1993), but it is unclear whether this is associated with fast elimination of cysts from cattle tissues (Dubey, 1983), or there is inconsistent cyst formation following infection. In addition to farm location in the western region, the only other risk factor determined for cattle infection was small herd size. According to the type of housing, the results showed that access to outside pens was protective as compared to total confinement. This apparently paradoxical finding may represent a further argument for the importance of the way in which feed is kept, or possibly indicates involvement of other farm factors not identified in this type of study.

44 Toxoplasmosis – Recent Advances

Cattle 611 76.3 MAT (1:25) Farms +

Pigs 605 28.9 MAT (1:25) Farms +

Sheep 367 7.1 unknown Aborting

Rats 80 27.5 MAT (1:25)

Rats 144 7.6 Microscopy Mice 12 3 Microscopy Rats 144 10.4 Real-time PCR Mice 12 83.3 Real-time PCR

Sheep 511 84.5 MAT (1:25) Farms Klun et al., 2006

Sheep 30 36.7 IFAT (1:20) Farm Lalošević et al.,

Pigs 488 9.2 MAT (1:25) Abattoir Klun et al., 2011 Goats 356 74.7 MAT (1:25) Farms Djokić et al., 2011

Pigeons 30 13.3 MAT (1:25) Urban (wild) Personal

Sheep 380 48.2 IHAT (1:10) Farms Prelezov et al.,

Sheep 840 53.4 IFAT Farms Kontos et al., 2001 Sheep 450 58.5 ELISA

Sheep 184/182 52.2/50.5 ELISA (a) Organic farms Ntafis et al., 2007 Goats 229/167 22.3/18 ELISA (a)

equids 753/773 1.7/1.8 ELISA (a) Farms Kouam et al., 2010 Dogs 2512 31.8 ELISA unknown Haralabidis &

Diakou et al., 2011 Pigeons 50 0 ELISA Urban (wild)

Cattle 105 20 ELISA Dairy farms Diakou et al.,

Goats 364 59.8 IHAT (1:10) 2008

Goats 280 62.9 2005b

643 0 – 16.7 Agar gel micro

Sheep 350 52.6 ELISA Mixed stock

Pigeons 379 5.8 ELISA Domestic

Σ Pigeons 429 5.1 ELISA Σ

**Table 2.** *Toxoplasma gondii* infection in animals in SEE countries in the last 20 years

Horses 250 30.8 MAT (1:25) Farms Klun, 2005

abattoir

abattoir

sheep Vidić et al., 2007

Urban Vujanić et al., 2011

precipitation Wild Arnaudov et al.,

farms

flocks

2008

observations

2003

2005a

Diakou et al.,

Diakou, 1999

Serbia

Bulgaria

Greece (mainland)

Wild animals (7 species)

Horses/

(a) Mean ODnegative controls + 3SD

The same study showed a prevalence of 85% in sheep in Serbia, of which 10% had high antibody levels of ≥1:1600, suggestive of acute infection. Although arbitrary, the cut-off of 1:1600 is even conservative since Dubey and Welcome (1988) had considered a titre of 1:1024 high. However, correlation with ovine abortions could not be established, since etiological laboratory diagnosis of ovine abortions in Serbia does not include diagnosis of *T. gondii*. Regionwise, similarly as with cattle, sheep from Western Serbia were at an increased risk of infection as compared to all other regions (Table 3). An increased risk of infection was also found in state-owned vs. private large flocks. Compared to other SEE countries, the prevalence of 85% is quite high; in Croatia and Bulgaria the highest recorded prevalence in sheep is 48%, and in Greece 58.5% (Table 2). This is also evident in goats; compared with the prevalence of 74.7% established in Serbia (Djokić et al., 2011), it was lower in Greece (62.9%) (Diakou et al., 2005b) and Bulgaria (59.8%) (Prelezov et al., 2008), and very markedly so in Croatia – 8.4% (Rajković-Janje et al., 1993).

An outbreak of toxoplasmosis in sheep has recently been reported; massive abortions (60%) occurred in a flock of 500 dairy sheep in Northern Greece at 110-130 days of pregnancy, diagnosed upon observation of tissue cysts in brain smears of aborted fetuses, and by serological (ELISA) examinations of mother and fetal serum samples. The abortion rate declined immediately upon instituting sulfadimidine therapy (Giadinis et al., 2011).

In horses, who generally have lower seroprevalence values than small ruminants (van Knapen et al., 1982), a prevalence of 30.8% has been determined in a study in Serbia (Klun, 2005), *vs.* only 1.7% in Greece (Kouam et al., 2010).

In pigs, an overall seroprevalence of 29% was established in Serbia (Klun et al., 2006). Of those seropositive, 4% were likely to be in the acute stage of infection, indicating continuous presence of infection reservoirs in the environment. Risk factors included age and farm type (Table 3). Since pigs are continuously exposed to infection, the increase in the risk of infection with age, ranging from 15% in market weight age pigs to 41% in adults, was expected, and repeated previous findings (Dubey et al., 1991; Dubey et al., 1995; Weigel et al., 1995; Damriyasa et al., 2004). Pigs on finishing type farms were four-fold more likely to be infected than those from farrow-to-finish farms. According to these results, it was proposed that a national strategy to reduce the level of *T. gondii* infection in pigs should include a shift towards the development of more farrow-to-finish farms, as well as vigilance in farm management and implementation of zoo-hygienic measures at finishing farms. Damriyasa et al. (2004) stated that *T. gondii* seropositivity is an indicator of the hygienic status of the pig farm.


*Toxoplasma gondii* Infection in South-East Europe: Epidemiology and Epizootiology 47

A recent study on *T. gondii* infection in slaughter pigs in Serbia (Klun et al., 2011) showed, however, a three-fold lower prevalence of 9.2% in a total of 488 swine from abattoirs in the vicinity of Belgrade. This difference was largely attributed to the difference in the studied samples since the latter one consisted of a large majority (96%) of market-weight pigs, who generally have a much lower prevalence than adult pigs. Similarly to the 2006 study, risk factors for infection in slaughter pigs included age and farm type with a 41-fold higher likelihood of infection in adult *vs.* market-weight pigs (*p*<0.001), and a 15-fold higher likelihood of infection in pigs of all ages from smallholders' finishing type farms (*p*<0.001)

On the other hand, the modern approach in farm management to provide for the welfare of the animals as well as organic food for human consumption is to develop animal-friendly (organic) farms. According to experiences from the Netherlands (Kijlstra et al., 2004), development of such farms may result in an increase in *T. gondii* infection. Nevertheless, a single report from organic sheep and goat farms in Greece (Ntafis et al., 2007) showed similar prevalence rates to those in animals from conventionally managed farms (Kontos et

A major reason for the control of *T. gondii* infection in meat animals is the reduction of the reservoir of human infection. Cattle are generally thought not to be significant in this context (Dubey and Thulliez, 1993). However, beef is often consumed undercooked ('rare' beef steaks, roast beef, steak tartar), and at least one outbreak of toxoplasmosis whose source was raw beef has been documented (Smith, 1993). In addition, one out of four beef samples randomly chosen from UK retail outlets tested positive for *T. gondii* by PCR (Aspinall et al., 2002). These facts, along with the circumstantial evidence provided by the data on the high prevalence of cattle infection of 92% in Italy and 69% in France (see Tenter et al., 2000), and now in Serbia, countries in which human infection is highly prevalent as well, all suggest a role for cattle as a *T. gondii* reservoir for human infection. In addition, Bobić et al. (2007) have demonstrated that among all the meat consumed, undercooked beef presents the highest risk for human infection in Serbia. Similarly, although Opsteegh et al. (2011a) did not establish a correlation between seropositivity and the detection of parasites in cattle, a study in which the relative contribution of sheep, beef and pork products to human *T. gondii* infection in the Netherlands was quantified (by Quantitative Microbial Risk Assessment), showed that beef is indeed an important source even if the seroprevalence in

On the other hand, according to official statistical reports (RZS, 2006–2010), pork represents approximately 50% of all meat consumed in Serbia. Thus, although pigs were the least infected of the examined species, given the findings that the prevalence increases with age and reaches 41% in sows (Klun et al., 2006), pork consumption may significantly contribute to human infection. When used for cooking, pork is generally properly thermally processed, but in most of the SEE countries' tradition mature pork is also highly valued for making delicatessen meat products. Raw or improperly cured sausages and ham are the source of small (family) epidemics of trichinellosis which, in spite of mandatory meat examination for

*vs.* those from farrow-to-finish intensive farms.

al., 2001; Diakou et al., 2005b).

cattle is low (Opsteegh et al., 2011b).

**Table 3.** Risk factors for *T. gondii* infection in meat animals in Serbia in 2003. Final logistic regression models. Results presented as adjusted odds ratio (OR) and 95% confidence intervals (CI) (modified from Klun et al., 2006)

A recent study on *T. gondii* infection in slaughter pigs in Serbia (Klun et al., 2011) showed, however, a three-fold lower prevalence of 9.2% in a total of 488 swine from abattoirs in the vicinity of Belgrade. This difference was largely attributed to the difference in the studied samples since the latter one consisted of a large majority (96%) of market-weight pigs, who generally have a much lower prevalence than adult pigs. Similarly to the 2006 study, risk factors for infection in slaughter pigs included age and farm type with a 41-fold higher likelihood of infection in adult *vs.* market-weight pigs (*p*<0.001), and a 15-fold higher likelihood of infection in pigs of all ages from smallholders' finishing type farms (*p*<0.001) *vs.* those from farrow-to-finish intensive farms.

46 Toxoplasmosis – Recent Advances

Cattle Herd size

Region

Sheep Farm type

Region

Pigs Age group

Farm type

from Klun et al., 2006)

Type of housing

Large (n>100) 1.00

Stable only 1.00

Northern Serbia 1.00

Private large (n>100) 1.00

Northern Serbia 1.00

Market weight (<8 months) 1.00

Farrow-to-finish 1.00

**Species Factor Adjusted OR 95% CI** *P***-value** 

Small (n<10) 2.19 1.28–3.75 0.004

 Access to outside pens 0.37 0.21–0.67 0.001 Access to pasture 0.72 0.25–2.07 0.548

 Western Serbia 2.04 1.10–3.79 0.024 Central/Eastern Serbia 0.97 0.32–2.90 0.951 Belgrade District 0.60 0.30–1.20 0.148

 State-owned (n>100) 4.18 2.18–8.00 <0.001 Private small (n<10) 1.79 0.55–5.81 0.332

 Western Serbia 4.66 1.18–18.32 0.028 Central/Eastern Serbia 0.82 0.25–2.73 0.748

Adult (≥8 months) 3.87 2.60–5.76 <0.001

Finishing 3.96 1.97–7.94 <0.001

**Table 3.** Risk factors for *T. gondii* infection in meat animals in Serbia in 2003. Final logistic regression models. Results presented as adjusted odds ratio (OR) and 95% confidence intervals (CI) (modified

On the other hand, the modern approach in farm management to provide for the welfare of the animals as well as organic food for human consumption is to develop animal-friendly (organic) farms. According to experiences from the Netherlands (Kijlstra et al., 2004), development of such farms may result in an increase in *T. gondii* infection. Nevertheless, a single report from organic sheep and goat farms in Greece (Ntafis et al., 2007) showed similar prevalence rates to those in animals from conventionally managed farms (Kontos et al., 2001; Diakou et al., 2005b).

A major reason for the control of *T. gondii* infection in meat animals is the reduction of the reservoir of human infection. Cattle are generally thought not to be significant in this context (Dubey and Thulliez, 1993). However, beef is often consumed undercooked ('rare' beef steaks, roast beef, steak tartar), and at least one outbreak of toxoplasmosis whose source was raw beef has been documented (Smith, 1993). In addition, one out of four beef samples randomly chosen from UK retail outlets tested positive for *T. gondii* by PCR (Aspinall et al., 2002). These facts, along with the circumstantial evidence provided by the data on the high prevalence of cattle infection of 92% in Italy and 69% in France (see Tenter et al., 2000), and now in Serbia, countries in which human infection is highly prevalent as well, all suggest a role for cattle as a *T. gondii* reservoir for human infection. In addition, Bobić et al. (2007) have demonstrated that among all the meat consumed, undercooked beef presents the highest risk for human infection in Serbia. Similarly, although Opsteegh et al. (2011a) did not establish a correlation between seropositivity and the detection of parasites in cattle, a study in which the relative contribution of sheep, beef and pork products to human *T. gondii* infection in the Netherlands was quantified (by Quantitative Microbial Risk Assessment), showed that beef is indeed an important source even if the seroprevalence in cattle is low (Opsteegh et al., 2011b).

On the other hand, according to official statistical reports (RZS, 2006–2010), pork represents approximately 50% of all meat consumed in Serbia. Thus, although pigs were the least infected of the examined species, given the findings that the prevalence increases with age and reaches 41% in sows (Klun et al., 2006), pork consumption may significantly contribute to human infection. When used for cooking, pork is generally properly thermally processed, but in most of the SEE countries' tradition mature pork is also highly valued for making delicatessen meat products. Raw or improperly cured sausages and ham are the source of small (family) epidemics of trichinellosis which, in spite of mandatory meat examination for

*Trichinella spiralis*, occasionally occur in Serbia (Djordjević 1989, Čuperlović et al., 2005), and thus, are a quite plausible source of human *T. gondii* infection as well.

*Toxoplasma gondii* Infection in South-East Europe: Epidemiology and Epizootiology 49

This work has been supported by project grant No. III 41019 from the Ministry of Education

[1] Ajzenberg D, Cogné N, Paris L, Bessieres MH, Thulliez P, Fillisetti D, Pelloux H, Marty P, Dardé ML (2002): Genotype of 86 *Toxoplasma gondii* isolates associated with human congenital toxoplasmosis and correlation with clinical findings. J Infect Dis 186: 684*–*689*.* [2] Arnaudov D (1971): [Study on the prevalence of toxoplasmosis in farm animals]. Vet Sci

[3] Arnaudov D (1973): [Comparative studies on complement binding test, indirect haemagglutination reaction and agar gel microprecipitation for diagnostics of

[4] Arnaudov D (1978): [Comparative studies of the virulent and immunogenic properties of the *Toxoplasma* strains isolated from domestic animals]. Vet Med Nauki 15: 38-46. [5] Arnaudov D, Arnaudov A (2005): Isolation *of Toxoplasma gondii* from domestic and wild animals. Balkan Scientific Conference on Biology, Plovdiv, Bulgaria, May 19-21.

[6] Arnaudov D, Kozojed V, Jíra J, Stourac L (1976): [Immunoepizootological study of

[7] Arnaudov D, Arnaudov A, Kirin D (2003): Study on the Toxoplasmosis among wild

[8] Aspinall TV, Marlee D, Hyde JE, Sims PF (2002); Prevalence of *Toxoplasma gondii* in commercial meat products as monitored by polymerase chain reaction – food for

[9] Aspöck H, Pollak A (1992): Prevention of prenatal toxoplasmosis by serological screening of pregnant women in Austria. Scand J Infect Dis 84 (Suppl): 32-37. [10] Berger F, Goulet V, Le Strat Y, Desenclos JR (2009): Toxoplasmosis among pregnant women in France: risk factors and change of prevalence between 1995 and 2003. Rev

[11] Bobić B, Djurković-Djaković O, Šibalić D, Jevremović I, Marinković J, Nikolić A, Vuković D (1996): Epidemiological relationship of the cat and human toxoplasma

[12] Bobić B, Jevremović I, Marinković J, Šibalić D, Djurković-Djaković O (1998): Risk factors for *Toxoplasma* infection in a reproductive age female population in the area of Belgrade,

[13] Bobić B, Nikolić A, Djurković-Djaković O (2003): Identification of risk factors for infection with *Toxoplasma gondii* in Serbia as a basis of a programme for prevention of

[14] Bobić B, Nikolić A, Klun I, Vujanić M, Djurković–Djaković O (2007): Undercooked meat consumption remains the major risk factor for *Toxoplasma* infection in Serbia.

toxoplasmosis in farm animals]. Vet Sci (Sofia) 10: 43-53.

ovine toxoplasmosis]. Vet Med (Praha) 21: 375-384.

animals, J Exp Path Parasitol *BAS* (Sofia) 6: 51-54.

infection in Belgrade. Acta Vet (Belgrade) 45: 155-160.

congenital toxoplasmosis. Srp Arh Celok Lek 131: 162-167.

thought? Int J Parasitol 32: 1193-1199.

Epidemiol Sante Publique 57: 241-248.

Yugoslavia. Eur J Epidemiol 14: 605-610.

Parassitologia 49: 227-230.

Proceedings (ed. by Gruev B, Nikolova M, Donev A): pp. 41-47.

**Acknowledgement** 

and Science of Serbia.

(Sofia) 8: 61-67.

**5. References** 

For most meat animals, although a trend is generally (worldwide) difficult to establish due to the scarcity of studies in most countries (no two time points), there is no visible reduction in the prevalence of *T. gondii* infection, as opposed to the decreasing trend in humans, discussed in detail earlier in this chapter (and explained by reasons including increased frozen meat use, better farm management etc.). For the most part, farming practices and environmental contamination have not changed, and except for the intensive pig farms in which a major reduction in *T. gondii* prevalence has occurred, a decline in the prevalence of *T. gondii* infection in meat animals is yet to be achieved. Moreover, for strictly herbivorous species that require outdoor access, this is probably impossible (Kijlstra & Jongert, 2009).

Ubiquitous contamination of the environment is also evident from the presence of *T. gondii* in both farm and urban rodents (Kutičić et al., 2005; Vujanić et al., 2011), wild animals, and pigeons (Arnaudov et al., 2003; Arnaudov & Arnaudov, 2005; Diakou et al., 2011) (Table 2). In dogs, studies performed in Greece have shown a prevalence ranging from 21.2% to 30.8% (Chambouris et al., 1989), and of 31.8%, in a large series of 2512 dogs from the regions of Macedonia and Thrace (Haralabidis & Diakou, 1999). As long as there is evidence of such widespread environmental contamination in SEE, a change for the better and a decrease of *T. gondii* infection in meat animals may hardly be expected in the absence of energetic and systematic prevention measures throughout the region.

#### **4. Conclusion**

Existing strategies for the prevention of toxoplasmosis in countries which have been implementing them for years have led to a decrease in its incidence, but have not solved the problem of congenital infection. This clearly shows that new comprehensive strategies for the prevention of toxoplasmosis are needed. These should be based on accurate and validated data on (1) the routes and risk factors for human infection on local level, which will allow for a more efficient health education; (2) routes and risk factors for meat animal infection to diminish infection reservoirs; (3) environmental contamination. Epidemiological and epizootiological data presented in this chapter show how far along this road we have come, and more importantly, how far we still have to go to achieve successful prevention of *T. gondii* infection in the SEE region.

### **Author details**

Branko Bobić, Ivana Klun, Aleksandra Nikolić and Olgica Djurković-Djaković\* *National Reference Laboratory for Toxoplasmosis, Centre for Parasitic Zoonoses (Centre of Excellence in Biomedicine), Institute for Medical Research, University of Belgrade, Serbia* 

<sup>\*</sup> Corresponding Author

#### **Acknowledgement**

This work has been supported by project grant No. III 41019 from the Ministry of Education and Science of Serbia.

#### **5. References**

48 Toxoplasmosis – Recent Advances

**4. Conclusion** 

**Author details** 

Corresponding Author

 \*

*T. gondii* infection in the SEE region.

*Trichinella spiralis*, occasionally occur in Serbia (Djordjević 1989, Čuperlović et al., 2005), and

For most meat animals, although a trend is generally (worldwide) difficult to establish due to the scarcity of studies in most countries (no two time points), there is no visible reduction in the prevalence of *T. gondii* infection, as opposed to the decreasing trend in humans, discussed in detail earlier in this chapter (and explained by reasons including increased frozen meat use, better farm management etc.). For the most part, farming practices and environmental contamination have not changed, and except for the intensive pig farms in which a major reduction in *T. gondii* prevalence has occurred, a decline in the prevalence of *T. gondii* infection in meat animals is yet to be achieved. Moreover, for strictly herbivorous species that require outdoor access, this is probably impossible (Kijlstra & Jongert, 2009).

Ubiquitous contamination of the environment is also evident from the presence of *T. gondii* in both farm and urban rodents (Kutičić et al., 2005; Vujanić et al., 2011), wild animals, and pigeons (Arnaudov et al., 2003; Arnaudov & Arnaudov, 2005; Diakou et al., 2011) (Table 2). In dogs, studies performed in Greece have shown a prevalence ranging from 21.2% to 30.8% (Chambouris et al., 1989), and of 31.8%, in a large series of 2512 dogs from the regions of Macedonia and Thrace (Haralabidis & Diakou, 1999). As long as there is evidence of such widespread environmental contamination in SEE, a change for the better and a decrease of *T. gondii* infection in meat animals may hardly be expected in the absence of energetic and

Existing strategies for the prevention of toxoplasmosis in countries which have been implementing them for years have led to a decrease in its incidence, but have not solved the problem of congenital infection. This clearly shows that new comprehensive strategies for the prevention of toxoplasmosis are needed. These should be based on accurate and validated data on (1) the routes and risk factors for human infection on local level, which will allow for a more efficient health education; (2) routes and risk factors for meat animal infection to diminish infection reservoirs; (3) environmental contamination. Epidemiological and epizootiological data presented in this chapter show how far along this road we have come, and more importantly, how far we still have to go to achieve successful prevention of

Branko Bobić, Ivana Klun, Aleksandra Nikolić and Olgica Djurković-Djaković\*

*in Biomedicine), Institute for Medical Research, University of Belgrade, Serbia* 

*National Reference Laboratory for Toxoplasmosis, Centre for Parasitic Zoonoses (Centre of Excellence* 

thus, are a quite plausible source of human *T. gondii* infection as well.

systematic prevention measures throughout the region.


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**Chapter 3** 

© 2012 Bartova and Sedlak, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

**Toxoplasmosis in Animals in the Czech Republic** 

Toxoplasmosis is a significant zoonosis that affects humans and warm blooded animals. The definitive hosts of parasite *Toxoplasma gondii* are cats and other felids. Many species of

In humans, clinical form of toxoplasmosis is rare in immunocompetent people, while it may leads to eye diseases, CNS or generalized infection in immunocompromissed individuals as well as interfere with the course or outcome of pregnancy. In Europe, *T. gondii* seroprevalence in humans ranges from 8% to 77% (Dubey 2010). In the Czech Republic, *T. gondii* antibodies were detected in 35% and 25% pregnant women by Sabin-Feldman Test (SFT) and Complement Fixation Test (CFT), respectively (Hejlicek et al. 1999). Repeated prevalence studies in humans in some European countries (France, Belgium, Sweden and Norway), revealed an evident trend of a decrease in *T. gondii* seroprevalence (Welton and Ades 2005). The same trend is observed in the Czech Republic. The prevalence of infection varies among ethnic groups due to sanitary and cooking habits. Consumption of raw or almost raw, dried, cured or smoked meat from domestic animals, unpasteurized goat milk or consumption of meat from wild animals may be associated with ingestion of the parasite (Kijlstra and Jongert 2008, Jones et al. 2009). Higher prevalence was found also in people who had frequent contact with animals and soil, such as abattoir workers, garbage handlers and waste pickers (Dubey and Beattie 1988). Children playing with dogs and cats can be infected by direct contact because animals can act as mechanical vectors (Etheredge et al.

In animals, *T. gondii* infection is a frequent cause of early embryonic death and resorption, fetal death and mummification, abortion, still birth and neonatal death. Thus, toxoplasmosis in domestic and farm animals is a disease of great importance for veterinary medicine and

and reproduction in any medium, provided the original work is properly cited.

**– The Last 10 Years** 

Eva Bartova and Kamil Sedlak

http://dx.doi.org/10.5772/50022

**1. Introduction** 

2004).

Additional information is available at the end of the chapter

domestic, wild or zoo animals may serve as intermediate hosts.

husbandry since it can cause productive and economic losses.

