The true individual seroprevalence in five province studies was 37.7%. (95% CI) and the number of cases was positive (139/368). The seroprevalence at the herd level was 94.44% (95% CI) and the number of herds considered positive was 34/36.
According to our study (Table 1), animals aged over 5 years old (49.27%) were the most infested compared to animals aged 2 to 5 years old (41.39%) and under 2 years old (24.77%) (p<0.001). The prevalence among females (40.39%) was significantly higher than among males (25.75%) (p<0.001). Farms whose numbers were between 20 and 50 (31.88%) were the least infested compared to farms whose numbers were less than 20 (52.94%) or greater than 50 (39.06%) (p<0.001). No significant differences were recorded in relation to type of breeding, intensive breeding (38.09%) and semi-extensive breeding (37.70%). Seroprevalence is higher in animals whose hygiene mode of box storage food is poor (41.66%) compared to those whose hygiene is good (34.90%) (p<0.05) and is higher in animals in pasture and supplemented with concentrate (44.01%) compared to animals in pasture only (34.54%) and animals in pasture and fed with concentrate and hay (26.92%) (p<0.01).
Seroprevalence is significantly associated with the season. The results showed that the seroprevalence is higher in winter (47.73%) compared to the spring season (26.03%) (p<0.001) and is significantly associated with the quality of water; herds that consume river water are more infested (51.89) than herds that consume tap water (33.91) (p<0.01). The Constantine region showed the lowest seroprevalence (22.72) and the highest was recorded in Skikda (46.98%) (p<0.05). Finaly, the presence of cats, rats and birds (p<0.0001) was significantly associated with seroprevalence in this study.
The seroprevalence recorded in our study (37.7%) was less than that recorded in France. 65.6% (Dumètre
et al, 2006), 46.5% in spain (
Jimenez-Martin et al., 2020), 53.8% in Italia
(Condoleo et al., 2023), 50.6 % in Romania
(Hotea et al., 2021), 52.8% in Ethiopia (Jilo el al., 2021), 41.7% in Estonia
(Maarja-Tagel et al., 2019), 56.6% in Lebanon
(Khalife et al., 2022), 42.85% in India
(Pandit et al., 2021), 60.7 % in lybia
(Hailazakis et al., 2021), 60.1% in Senegal
(Dahourou et al., 2019), 64.4 % in south of Africa
(Tagwireyi et al., 2019), 39.1 % in Egypt
(Abdelbaset et al., 2020) and it was higher than recorded in bénin 1.4%
(Tonouhewa et al., 2019), 34.3% in Brazil (De
Moura et al., 2021), 31.29% in china
(Jia et al., 2023), 35.9% in mexico
(Suazo-Cortez et al., 2020), 4.5% in turkey (
Aktaş and Aydın, 2020), 30% in morocco
(Benkirane et al., 2015), 19.7% in Tunisia
(Guesmi et al., 2023), 25.6% in Algeria
(Abdallah et al., 2019), 35.9% in algeria also
(Ouchene et al., 2023).
The variation in global prevalence seen in this study and others previously noted may be explained by the degree to which the small ruminants had access to contaminated feed and water, climate variables and the diagnostic procedures used (
Dubey, 2004;
Innes et al., 2009).
Animals aged over 5 years old (49.27%) were the most infested in our study, these results are similar to those founded by
Abdallah et al., (2019) and
Niaz et al., (2016) Jittapalapong et al. (2005). This might be the result of the adults’ prolonged exposure to the
T.
gondii infection (
Dubey, 2019).
According to
Dubey et al., (1998), females may have weaker immunological resistance at particular stages of their lives, which can explain the higher sensitivity. In Algeria, small herds are typically managed by traditional methods. Firstly, cats have easy access to the livestock’s food. Second, the animals graze frequently and every day, a transition from extensive to intensive grazing and back again occurred. Thirdly, there are no animal hygiene procedures, including organizing feeding or cleaning
(Abdallah et al., (2019).
In this study seroprevalence is higher in animals whose hygiene mode of box storage food is poor (41.66%). These results are comparable to those of
Cosendey-KezenLeite et al., (2014) because farm hygiene, cleaning and disinfection practices may be crucial in the transmission of T. gondii infections to livestock. This is because cleaning decreases the risk of oocyst contamination of the facilities and can also minimize exposure to infected intermediate hosts, such as rodents.
According to various research studies
(Dubey et al., 1996; Ruiz and Frenkel, 1980), the high oocyst contamination of agricultural soil may be the cause of this high prevalence. Grazing systems, where several herds graze each day, are responsible for these agreements, as a result, herds of animals were in significant danger of coming into contact with contaminated feed and grass throughout the grazing season
(Abdallah et al., 2019). The higher seroprevalence in winter season in our study could be explained because sheep in winter are typically confined throughout the night and on days of severe weather and they are supplied supplemental feed consisting of hay, grass silage and concentrates and cats have easy access to the livestock's food.
In our study constantine region where dry climate showed the lowest seroprevalence (22.72) and the highest was recorded in coastal area in skikda (46.98%) (p<0.05). The parasite’s ability to survive and spread epidemiologically is negatively impacted by a dry climate (
Dubey, 2019;
Tegegne et al., 2016). On the contrary, in the coastal cities of Algeria, the high levels of wetness increase the likelihood that oocysts will survive in the environment and that they will come into contact with contaminating sources, resulting in increased seroprevalence (
Dubey, 2019;
Tilahun et al., 2019; Jones et al., 2001).
Seroprevalence is significantly associated with the presence of cats, rats and birds (p<0.0001) in this study, the prevalence at farms whose cats are present and have access to box food storage was 34.09%. This founding are different than showed by
ramzan et al. (2009). The observation of a higher seroprevalence in domestic ruminants, which supports the high incidence of toxoplasmosis in women seen in Algeria, affirms the role of cats as a source of
T.
gondii infection
(Messerer et al., 2014; Berredjem et al., 2017). Even on farms without the presence of cats, the seroprevalence was higher (55.55%). That could be explained by the possibility that animals became infected for the first time outside of these farms or in contaminated pasture by other stray cats. More research is needed to determine how long the infection remains in the animals.
The rate of infection in local populations of birds and rodents determines the rate of infection in cats because cats contract the infection by eating these animals. Cat infection rates would rise as a result of prey animals becoming more prone to contracting the disease when there are more oocysts in the environment
(Hill et al., 2005). Wide natural infection of the environment exists because a cat could eliminate millions of oocysts after consuming as little as one bradyzoite or one tissue cyst and one infected mouse may contain numerous tissue cysts
(Frenkel et al., 1970; Dubey, 2001).
