Global Status of Toxoplasma gondii Seroprevalence in Rodents: A Systematic Review and Meta-Analysis

Abstract

Toxoplasmosis is one of the most prevalent infections in humans and animals caused by the intracellular protozoan parasite Toxoplasma gondii (T. gondii). Rodents, as intermediate and reservoir hosts, play a key role in the maintenance and transmission of T. gondii. They can be contaminated and maintain the parasite in the form of cysts in their bodies, demonstrating an infection source for their offsprings, predators (particularly felids), and other animals. Therefore, the present systematic review and meta-analysis study was carried out to evaluate the global seroprevalence of T. gondii in these mammals. For achieving the purpose of the current study, six English databases (PubMed, Science Direct, Web of Science, Scopus, ProQuest, and Google Scholar) were systematically searched for related studies from 1970 to 2018. Finally, a total of 52,372 records were screened, 105 records including 26,221 rodents were incorporated in the present study. By random effect models, the overall seroprevalence was calculated at 6% (95% CI = 6-7%), with the highest amount was observed in Africa (24%) and South America (18%), and the lowest amount in Europe (1%). The subgroup data analysis by gender manifested that the prevalence of Immunoglobulin G antibodies did not differ between genders (P > 0.05). Due to the significant heterogeneity, meta-regression models were applied based on serological techniques and continental regions; however, the obtained values were not statistically significant (P = 0.480 and P = 0.295, respectively). The present study revealed a relatively low level of T. gondii seroprevalence in rodents; however, if they were the main food source for their predators, they would cause high transmission of T. gondii.

Seroprevalence of Toxoplasma gondii among sylvatic rodents in Poland

“…We found that female bank voles were 3.5 times more likely to be infected with T. gondii than males, and in this respect, our data contrast with reports in the literature in which T. gondii seropositivity in male rodents has been recorded generally to be higher than in females (14). It was not unexpected to find in our study that older animals were more likely to have experienced infection than juveniles, since the current work was based on the presence/absence of specific antibody against T. gondii , reflecting the history of previous infections and not necessarily a current infection.…”

“…Therefore, they may potentially play a role as reservoirs of this parasite in the sylvatic environment. According to the meta-analysis carried out by Galeh and colleagues, the overall seroprevalence of anti-Toxoplasma IgG antibodies in rodents in Europe is 1% (14). Here, we report an overall seroprevalence of T. gondii in voles of 5.5%, with Microtus and Alexandromys spp.…”

Prevalence of Toxoplasma gondii infection among small mammals in Tatarstan, Russian Federation

“…The overall T. gondii prevalence in these small mammals was 8.44 %. In several European countries (France, Czech Republic, Sweden and Switzerland) the prevalence of T. gondii among wild small mammals living in rural forests was 3-7 %, which is not dissimilar to our results 13,15 . Using logistical regression analysis, we found that the trapping area (rural/urban), but not the vegetation in the trapping spots, species, sex, age or distance from the trapping points to the nearest human settlements, signi cantly contributed to the prevalence of T. gondii among the small mammals.…”

“…Multivariate logistic regression was performed using the R statistical software package (version 3.6.3) 29 to assess the trapping point area (urban or rural), vegetation (forest or eld), small mammal species type (alien or non-alien species), age (0-2 months-old juveniles, 3-6 months-old adults or ≧ 6 months old), sex (male or female) and distance from trapping points to the nearest human settlements as risk factors for PCR positivity. According to previous reports [14][15][16][17][18] , four species, Mi. arvalis, A. avicollis, A. agrarius, A. uralensis, and three species, My.…”

No evidence of Toxoplasma gondii infection in urban and rural squirrels

“…One earlier study from Guelph, Ontario, Canada found no evidence of infection across nine locations within and around the city from grey squirrels (Sciurus carolinensis, n= 16, the number of urban captures not specified) and chipmunks (Tamias striatus, n= 6) using the Sabin-Feldman dye test (Tizard et al 1978). Using serological techniques with bioassay and PCR together can give a more reliable estimation of infection rate (Galeh et al 2020), as the distribution of T. gondii tissue cysts can be uneven and vary between organs (Elmore et al 2016) which can lead to detection difficulties using PCR-based methods (Opsteegh et al 2010). The sensitivity and specificity of antibody detection methods can also vary, which can lead to misinterpretation of results and possible false negatives or false positives (Gilbert et al 2013).…”