Many cases of Toxoplasma gondii infection have been reported worldwide in non-human primates (NHPs), especially in captive New World monkeys. However, few studies on toxoplasmosis in Old World monkeys have been conducted. In this study, serological and molecular biological analyses were carried out to look for T. gondii antibodies and T. gondii infection in 13 NHPs from China. T. gondii infection was confirmed in 8 NHP cases. T. gondii antibodies were detected in 1/5 New World monkeys and in 4/7 Old World monkeys. T. gondii DNA was detected in 3/5 New World monkeys and 5/7 Old World monkeys. The one ring-tailed lemur was negative for both antibodies and DNA of T. gondii. The most common clinical manifestations of T. gondii infection were malaise, poor appetite, emaciation, and foamy nasal discharge. The most common histopathological findings were interstitial pneumonia, necrotic hepatitis, necrotizing myocarditis, lymphadenitis, and necrotic splenitis. One viable T. gondii strain was successfully isolated from the myocardium of a patas monkey (Erythrocebus patas) by bioassay in mice. T. gondii tachyzoites were obtained from cell cultures and were designated as TgMonkeyCHn2. The genotype of this strain belongs to ToxoDB genotype #9, and the allele of ROP18/ROP5 gene was 3/6. TgMonkeyCHn2 tachyzoites were avirulent in Swiss mice. To our knowledge, this is the first report of fatal toxoplasmosis in a patas monkey. T. gondii infection in patas monkeys may indicate environmental contamination by oocysts. The patas monkey is a new host record for T. gondii.

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.

In May 2025, a female giraffe in poor body condition died unexpectedly at a zoo in Henan Province, China. A bacterial strain, designated HN-1, was isolated from the heart, liver, spleen, lungs, and kidneys of the deceased animal. After 24 h of incubation at 37 °C on Luria–Bertani (LB) agar, the colonies appeared round, smooth, pale yellow, translucent, and raised. Gram staining revealed that the isolate was a Gram-positive, rod-shaped, and non-spore-forming bacterium. Based on 16S rRNA gene sequencing, the strain showed more than 99.7% homology with reference sequences of E. mexicanum from various sources in GenBank. The results of the susceptibility test showed that E. mexicanum was susceptible to levofloxacin, clindamycin, chloramphenicol, trimethoprim, rifampicin, tetracycline, minocycline, gentamicin, erythromycin, and doxycycline, but resistant to oxacillin, penicillin, ciprofloxacin, and linezolid. These findings provide valuable insights for the diagnosis and treatment of infections caused by E. mexicanum in giraffes.

In May 2025, a female giraffe in poor body condition died unexpectedly at a zoo in Henan Province, China. A bacterial strain, designated HN-1, was isolated from the heart, liver, spleen, lungs, and kidneys of the deceased animal. After 24 hours of incubation at 37°C on Luria–Bertani (LB) agar, the colonies appeared round, smooth, pale yellow, translucent, and raised. Gram staining revealed that the isolate was a Gram-positive, rod-shaped, and non-spore-forming bacterium. Based on 16S rRNA gene sequencing, the strain showed more than 99.7% homology with reference sequences of E. mexicanum from various sources in GenBank. The results of the susceptibility test showed that E. mexicanum was susceptible to levofloxacin, clindamycin, chloramphenicol, trimethoprim, rifampicin, tetracycline, minocycline, gentamicin, erythromycin, and doxycycline, but resistant to oxacillin, penicillin, ciprofloxacin, and linezolid. These findings provide valuable insights for the diagnosis and treatment of infections caused by E. mexicanum in giraffes.

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, hydroperitoneum, 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 by RFLP-PCR. The strain was avirulent in Swiss mice and matched the prediction of ROP18 and ROP5 gene alleles of TgCaracalCHn2 (2/2). Many 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 caracals can accelerate the transmission of T. gondii genotypes.