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Toxoplasma gondii is a widespread protozoan parasite that infects most warm-blooded animals, and felids can serve as intermediate and definitive hosts. Pathological diagnosis and serological and etiological investigations were conducted on a captive caracal (Caracal caracal) carcass collected from China in 2022. Pathological diagnosis revealed that cardiac insufficiency, pulmonary edema, hepatic failure, and renal insufficiency were the causes of the caracal's death. A modified agglutination test (cut-off: 1:25) revealed that IgG antibodies against T. gondii were present in the myocardium juice (1:1600), ascitic fluid (1:3200), and hydropericardium (1:800). A viable T. gondii (TgCaracalCHn2) strain was isolated from the tissue samples (heart, brain, spleen, and skeletal muscle) of this caracal using a mouse bioassay. The genotype of TgCaracalCHn2 was ToxoDB#5 (Type II variant), as determined via RFLP-PCR. The strain was avirulent in Swiss mice and matched the prediction of ROP18 and ROP5 gene alleles of TgCaracalCHn2 (2/2). Mild tissue cysts (203 ± 265) were observed in mice brains after inoculation with TgCaracalCHn2 tachyzoites. ToxoDB#5 is the dominant genotype in North American wildlife, and this is the first documented isolation of T. gondii ToxoDB#5 from China. This indicates that caracal plays an important role in the transmission of this T. gondii genotype. [ABSTRACT FROM AUTHOR]

Sheep are highly susceptible to Toxoplasma gondii, and miscarriage is the main clinical feature. This study investigated 227 sheep samples (210 myocardial tissues from slaughterhouses, 6 ewe serum samples, 3 aborted fetuses, and 8 dead lambs from veterinary clinics) from central China for T. gondii infection. Antibodies against T. gondii were detected using the modified agglutination test (MAT). PCR was performed to detect T. gondii DNA in the tissue samples. The results showed that four samples were seropositive (MAT titer ≥ 1:100), with a seroprevalence of 1.8% (4/227). The seropositive samples included two myocardial samples from a slaughterhouse, one ewe and its aborted fetus from a veterinary clinic. The results revealed that 7 out of 207 (3.4%) sheep tissue samples were PCR-positive, including two myocardial tissue samples from slaughterhouses, three aborted fetuses, and two lambs from veterinary clinics. Toxoplasma gondii vertical transmission had occurred in two of three pairs of ewes and her pups. One viable T. gondii strain (TgSheepCHn14) was isolated from the myocardial tissues of sheep from a slaughterhouse. Tachyzoites were obtained from cell cultures at 70 days following seeding in the brains and lungs of mice. This strain was non-lethal to Swiss mice. The number of parasite brain cysts in mice decreased with time post-infection (p < 0.05). Overall, the prevalence of T. gondii in the sheep samples was low. Although the samples were scattered, and not from planned collections, the current study detected T. gondii antibodies and DNA in aborted fetuses, indicating that vertical transmission could occur and maintain the parasites in sheep herds without exogenous infection. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii can infect almost all warm-blooded animals, including humans and dogs. Humans can become infected with T. gondii by petting dogs that have eaten or contacted infected cat feces. The aim of this study was to evaluate T. gondii infections in dogs from central China. From 2015 to 2021, a total of 536 dog samples (195 fecal, 81 hearts, and 260 serum samples) from Henan Province were collected. Heart juice or serum samples (n = 341) were tested for T. gondii antibodies using the modified agglutination test (MAT). Fresh myocardium (n = 6) and blood (n = 2) samples were bioassayed in mice. Results: The present study showed that 4.40% (15/341) of the dogs were seropositive for T. gondii by MAT (cut-off, 1:25) and 4.10% (8/195) of dog feces contained T. gondii DNA. No T. gondii DNA was found in any myocardium (n = 81) or blood (n = 2) samples. The viable T. gondii strain was not isolated from any myocardium or blood samples (n = 8). Compared to the prevalence of T. gondii antibodies in dogs sampled from 2015 to 2018, the prevalence significantly declined from 2020 to 2021 (P < 0.05). Gender and age were not risk factors for dogs infected with T. gondii in this study. However, compared to other sources, dogs from Zhoukou City (close to the Yellow River) or from pet shops showed significantly higher prevalence for T. gondii (P < 0.05). Conclusion: A total of 4.29% dogs were infected by T. gondii (23/536, 8 of 195 fecal samples, 2 of 260 serum, and 13 of 81 heart juice samples). This is the first survey of T. gondii infection in dog feces from China. Dogs were exposed to T. gondii , and they could act as mechanical transmitters of T. gondii. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is one of the most common foodborne diseases in the world. The objective of this study was to determine Toxoplasma gondii infection in lambs from Henan province, China. A total of 166 lamb hearts were collected from 2017 to 2019. T. gondii infection was determined by the Modified Agglutination Test (MAT) using heart juice of lambs. 11 isolates (TgSheepCHn3 - TgSheepCHn13) were obtained from samples with MAT titers ≥1:100. The rate of T. gondii isolation increased with antibody titer against T. gondii (P < 0.05). No isolate was obtained from samples with titer 1:25 and 1:50, suggesting the cut-off titer for MAT is better set at 1:100. With cut-off value of 1:100, IgG antibodies to T. gondii were found in 25.3% (42/166) of the lambs by MAT. T. gondii parasite was not found in IHC and HE-stained tissue sections of lamb hearts (0/166). Sixty-seven heart tissues with ≥1:25 MAT titers were subjected to acid pepsin digestion and detected T. gondii by PCR. Only 7.5% (5/67) of DNA amplified products were found in heart tissues by the primer TOX5/TOX8. Brain tissue cysts were observed in all mice infected with the 11 isolates at day 60 post infection, suggesting these isolates are non-lethal to mice. PCR-RFLP analysis revealed that 7 isolates belonged to ToxoDB#2, 4 isolates belonged to ToxoDB#4. This is the first isolation of ToxoDB#2 and ToxoDB#4 from lambs in China. Interestingly, none of these isolates belongs to the ToxoDB#9 that is common in China. Our results suggest that the genetic diversity and population structure of T. gondii from China maybe more abundant and magical than previous speculation. • A total of 25.3% (42/166) lambs showed sera conversion of T. gondii antibodies (cut-off titer for MAT: 1:100). • 11 viable T. gondii isolates were obtained from lambs, ToxoDB genotype #2 and #4 were identified. • The rate of isolation T. gondii increased with antibody titer against T. gondii in lamb (P < 0.05). [ABSTRACT FROM AUTHOR]