Toxoplasma gondii (T. gondii) is a globally distributed protozoan parasite that can infect a wide range of warm-blooded animals, including humans. Nonhuman primates (NHPs) are particularly valuable for studying toxoplasmosis because of their physiological and immunological similarity to humans. In this study, we report the isolation and characterization of two T. gondii strains from captive NHPs that died suddenly in a zoo in Guangdong Province, China. The animals, a red-backed bearded saki (Chiropotes chiropotes), a New World monkey, and a mandrill (Mandrillus sphinx), an Old World monkey, were diagnosed with acute fatal toxoplasmosis on the basis of histopathology, immunohistochemistry, serology (MAT), and PCR. Parasite isolation was performed via a mouse bioassay, and the strains were genotyped using multilocus PCR–RFLP. The isolates were identified as ToxoDB #15 and ToxoDB #169, atypical genotypes that have been reported in Africa, Europe, and the Americas. Pathogenicity assessment in Swiss mice revealed that both TgMonkeyGd2 (ToxoDB #15) and TgMonkeyGd3 (ToxoDB #169) exhibited intermediate virulence, causing 100% and 80% mortality at 104 tachyzoites, respectively, with lower doses allowing host survival and seroconversion. These findings challenge the traditional view that Old World monkeys (exemplified by the mandrill) are relatively resistant to toxoplasmosis and suggest a possible role of the wildlife trade in the transcontinental spread of exotic T. gondii genotypes, although this hypothesis requires further investigation with a larger number of cases. Enhanced surveillance and biosecurity measures are urgently needed in captive animal facilities to prevent outbreaks and protect both animal and public health.
| [1] |
Al-Kappany YM, Rajendran C, Abu-Elwafa SA, Hilali M, Su C, Dubey JP. Genetic diversity of Toxoplasma gondii isolates in Egyptian feral cats reveals new genotypes. The Journal of Parasitology, 2010, 96(6): 1112-1114
|
| [2] |
Ajzenberg D, Bañuls AL, Su C, Dumètre A, Demar M, Carme B, Dardé ML. Genetic diversity, clonality and sexuality in Toxoplasma gondii. International Journal for Parasitology, 2004, 34(10): 1185-1196
|
| [3] |
Behnke MS, Fentress SJ, Mashayekhi M, Li LX, Taylor GA, Sibley LD. The polymorphic pseudokinase ROP5 controls virulence in Toxoplasma gondii by regulating the active kinase ROP18. PLoS Pathogens, 2012, 8(11): e1002992
|
| [4] |
Behnke MS, Khan A, Lauron EJ, Jimah JR, Wang Q, Tolia NH, Sibley LD. Rhoptry proteins ROP5 and ROP18 are major murine virulence factors in genetically divergent south american strains of Toxoplasma gondii. PLoS Genetics., 2015, 11(8): e1005434
|
| [5] |
Carme B, Ajzenberg D, Demar M, Simon S, Dardé ML, Maubert B, de Thoisy B. Outbreaks of toxoplasmosis in a captive breeding colony of squirrel monkeys. Veterinary Parasitology., 2009, 163(1–2): 132-135
|
| [6] |
Catão-Dias, J. L., S. Epiphanio, and M. C. M. Kierulff 2013. Neotropical primates and their susceptibility to Toxoplasma gondii: new insights for an old problem. Primates, Pathogens, and Evolution 253–289. https://doi.org/10.1007/978-1-4614-7181-3_9.
|
| [7] |
Cedillo-Peláez C, Rico-Torres CP, Salas-Garrido CG, Correa D. Acute toxoplasmosis in squirrel monkeys (Saimiri sciureus) in Mexico. Veterinary Parasitology., 2011, 180(3–4): 368-371
|
| [8] |
Chen R, Lin X, Hu L, Chen X, Tang Y, Zhang J, Chen M, Wang S, Huang C. Genetic characterization of Toxoplasma gondii from zoo wildlife and pet birds in Fujian. China. Iranian Journal of Parasitology., 2015, 10(4): 663-668
|
| [9] |
de Sousa, D. E. R., I. L. de Macêdo, L. de Albuquerque Cerqueira, L. Melanie, V. F. Dos Santos Pessoa, A. S. da Silva Rocha, P. de Alcantara Brito Junior, P. H. de Oliveira Passos, D. G. Ramos, A. P. M. Romano. et al. 2025. Insights into the threats of toxoplasmosis for free-ranging black-tufted marmosets living in our neighborhood. Scientific Reports 15 (1): 16047. https://doi.org/10.1038/s41598-025-00495-4.
|
| [10] |
du Plooy, I., M. Mlangeni, R. Christian, and A. M. Tsotetsi-Khambule. 2023. An African perspective on the genetic diversity of Toxoplasma gondii: A systematic review. Parasitology. 150(7): 551–578. https://doi.org/10.1017/S0031182023000252.
|
| [11] |
Dubey JP. Toxoplasmosis of animals and humans, 20223Boca Raton, FL, USA, CRC Press: 1-542
|
| [12] |
Dubey, J. P., and G, Desmonts. 1987. Serological responses of equids fed Toxoplasmagondii oocysts. Equine Veterinary Journal. 19(4): 337–339. https://doi.org/10.1111/j.2042-3306.1987.tb01426.x.
|
| [13] |
Dubey JP, Murata FHA, Cerqueira-Cézar CK, Kwok OCH, Yang Y, Su C. Recent epidemiologic, clinical, and genetic diversity of Toxoplasma gondii infections in nonhuman primates. Research in Veterinary Science., 2021, 136: 631-641
|
| [14] |
Fentress SJ, Behnke MS, Dunay IR, Mashayekhi M, Rommereim LM, Fox BA, Bzik DJ, Taylor GA, Turk BE, Lichti CF, et al. . Phosphorylation of immunity-related GTPases by a Toxoplasma gondii-secreted kinase promotes macrophage survival and virulence. Cell Host & Microbe, 2010, 8(6): 484-495
|
| [15] |
Ferreira DR, Ribeiro VO, Laroque PO, Wagner PG, Pinheiro Júnior JW, Silva JC, Dubey JP, Rêgo EW, Mota RA. Risk factors associated with Toxoplasma gondii infection in captive Sapajus spp. American Journal of Primatology., 2015, 77(5): 558-562
|
| [16] |
Firouzeh, N., N. Ziaali, V. Sheibani, A. H. Doustimotlagh, A. Afgar, M. Zamanpour, H. Keshavarz, S. Shojaee, R. Shafiei, K. Esmaeilpour, et al. 2021. Chronic Toxoplasma gondii infection potentiates Parkinson’s disease course in a mouse model. Iranian Journal of Parasitology. https://doi.org/10.18502/ijpa.v16i4.7863.
|
| [17] |
Fleckenstein MC, Reese ML, Könen-Waisman S, Boothroyd JC, Howard JC, Steinfeldt T. A Toxoplasma gondii pseudokinase inhibits host IRG resistance proteins. PLoS Biology, 2012, 10(7): e1001358
|
| [18] |
Franklin-Murray, A. L., S. Mallya, A. Jankeel, S. Sureshchandra, I. Messaoudi, and M. B. Lodoen. 2020. Toxoplasma gondii dysregulates barrier function and mechanotransduction signaling in human endothelial cells. MSphere 5 (1). https://doi.org/10.1128/msphere.00550-19.
|
| [19] |
Furuta T, Une Y, Omura M, Matsutani N, Nomura Y, Kikuchi T, Hattori S, Yoshikawa Y. Horizontal transmission of Toxoplasma gondii in squirrel monkeys (Saimiri sciureus). Experimental Animals., 2001, 50(4): 299-306
|
| [20] |
Gazzinelli RT, Mendonça-Neto R, Lilue J, Howard J, Sher A. Innate resistance against Toxoplasma gondii: An evolutionary tale of mice, cats, and men. Cell Host & Microbe., 2014, 15(2): 132-138
|
| [21] |
Galal L, Hamidović A, Dardé ML, Mercier M. Diversity of Toxoplasma gondii strains at the global level and its determinants. Food and Waterborne Parasitology., 2019, 15: e00052
|
| [22] |
Huang, M., G. F. Li, G. L. Zhi, C. Y. Zhao, K. X. Liu, K. J. Zuo, H. Lan, X. J. Chen, and Z. G. Yuan. 2018. Isolation and identification of Toxoplasma gondii from black-crown squirrel monkey (Saimiri vanzolinii) of South China. Chinese Veterinary Science 48: 316–322. https://doi.org/10.16656/j.issn.1673-4696.2018.0056. (In Chinese).
|
| [23] |
Ma Y, Yang L, Yang Y. First isolation of viable Toxoplasma gondii from a black mangabey (Lophocebus aterrimus) reveals the emergence of the Africa 1 lineage in East Asia. PLoS Neglected Tropical Diseases., 2025, 19(7): e0013133
|
| [24] |
Niedelman W, Gold DA, Rosowski EE, Sprokholt JK, Lim D, Farid Arenas A, Melo MB, Spooner E, Yaffe MB, Saeij JP. The rhoptry proteins ROP18 and ROP5 mediate Toxoplasma gondii evasion of the murine, but not the human, interferon-gamma response. PLoS Pathogens., 2012, 8(6): e1002784
|
| [25] |
Niehaus, C., M. Spínola, C. Su, N. Rojas, O. Rico-Chávez, C. N. Ibarra-Cerdeña, J. Foley, G. Suzán, G. A. Gutiérrez-Espeleta, and A. Chaves. 2020. Environmental factors associated with Toxoplasma gondii exposure in neotropical primates of Costa Rica. Frontiers in Veterinary Science 7. https://doi.org/10.3389/fvets.2020.583032.
|
| [26] |
Nishimura M, Goyama T, Tomikawa S, Fereig RM, El-Alfy EN, Nagamune K, Kobayashi Y, Nishikawa Y. Outbreak of toxoplasmosis in four squirrel monkeys (Saimiri sciureus) in Japan. Parasitology International., 2019, 68(1): 79-86
|
| [27] |
Pardini L, Dellarupe A, Bacigalupe D, Quiroga MA, Moré G, Rambeaud M, Basso W, Unzaga JM, Schares G, Venturini MC. Isolation and molecular characterization of Toxoplasma gondii in a colony of captive black-capped squirrel monkeys (Saimiri boliviensis). Parasitology International., 2015, 64(6): 587-590
|
| [28] |
Paula NF, Dutra KS, Oliveira AR, Santos DOD, Rocha CEV, Vitor RWA, Tinoco HP, Costa MELTD, Paixão TAD, Santos RL. Host range and susceptibility to Toxoplasma gondii infection in captive neotropical and Old-world primates. Journal of Medical Primatology., 2020, 49(4): 202-210
|
| [29] |
Pena HF, Marvulo MF, Horta MC, Silva MA, Silva JC, Siqueira DB, Lima PA, Vitaliano SN, Gennari SM. Isolation and genetic characterization of Toxoplasma gondii from a red-handed howler monkey (Alouatta belzebul), a jaguarundi (Puma yagouaroundi), and a black-eared opossum (Didelphis aurita) from Brazil. Veterinary Parasitology., 2011, 175(3–4): 377-381
|
| [30] |
Reese ML, Shah N, Boothroyd JC. The Toxoplasma pseudokinase ROP5 is an allosteric inhibitor of the immunity-related GTPases. The Journal of Biological Chemistry., 2014, 289(40): 27849-27858
|
| [31] |
Reis Amendoeira MR, Arruda IF, Moreira SB, Ubiali DG, da Silva Barbosa A, Jesus Pena HF, Barbosa Pereira AH, Nascimento da Silveira C, Bonifácio TF, Clemes YS, et al. . Isolation and genetic characterization of Toxoplasma gondii from a captive black-and-gold howler monkey (Alouatta caraya Humboldt, 1812) in Brazil. International journal for parasitology. Parasites and Wildlife., 2022, 19: 187-190
|
| [32] |
Salant H, Weingram T, Spira DT, Eizenberg T. An outbreak of toxoplasmosis among squirrel monkeys in an Israeli monkey colony. Veterinary Parasitology., 2009, 159(1): 24-29
|
| [33] |
Salas-Fajardo MY, Benavides J, Azevedo A, Figueiras P, Monteiro M, Orge L, Mendonça P, Carvalho P, Waap H, Ortega-Mora LM, et al. . Fatal toxoplasmosis in a captive squirrel monkey (Saimiri boliviensis) in Portugal. Veterinary Research Communications., 2023, 47(4): 2363-2370
|
| [34] |
Santos SV, Pena HFJ, Talebi MG, Teixeira RHF, Kanamura CT, Diaz-Delgado J, Gennari SM, Catão-Dias JL. Fatal toxoplasmosis in a southern muriqui (Brachyteles arachnoides) from São Paulo state, Brazil: Pathological, immunohistochemical, and molecular characterization. Journal of Medical Primatology., 2018, 47(2): 124-127
|
| [35] |
Saraf P, Shwab EK, Dubey JP, Su C. On the determination of Toxoplasma gondii virulence in mice. Experimental Parasitology., 2017, 174: 25-30
|
| [36] |
Schares, G., D. C. Herrmann, A. Beckert, S. Schares, M. Hosseininejad, N. Pantchev, M. Globokar Vrhovec, and F. J. Conraths. 2008. Characterization of a repetitive DNA fragment in Hammondia hammondi and its utility for the specific differentiation of H. hammondi from Toxoplasma gondii by PCR. Molecular and cellular probes. 22 (4): 244–251. https://doi.org/10.1016/j.mcp.2008.04.003.
|
| [37] |
Shwab EK, Jiang T, Pena HF, Gennari SM, Dubey JP, Su C. The ROP18 and ROP5 gene allele types are highly predictive of virulence in mice across globally distributed strains of Toxoplasma gondii. International Journal for Parasitology., 2016, 46(2): 141-146
|
| [38] |
Shwab EK, Zhu XQ, Majumdar D, Pena HF, Gennari SM, Dubey JP, Su C. Geographical patterns of Toxoplasma gondii genetic diversity revealed by multilocus PCR-RFLP genotyping. Parasitology, 2014, 141(4): 453-461
|
| [39] |
Silva RCD, Machado GP, Cruvinel TMDA, Cruvinel CA, Langoni H. Frequency of Toxoplasma gondii antibodies in tufted capuchin monkeys (Cebus apella nigritus) from an ecological station in the state of São Paulo. Brazil. Pesquisa Veterinária Brasileira., 2013, 33(2): 251-253
|
| [40] |
Sousa DER, Wilson TM, Macêdo IL, Romano APM, Ramos DG, Passos PHO, Costa GRT, Fonseca VS, Mares-Guia MAMM, Giovanetti M, et al. . Case report: Urbanized nonhuman primates as sentinels for human zoonotic diseases: A case of acute fatal toxoplasmosis in a free-ranging marmoset in coinfection with yellow fever virus. Frontiers in Public Health., 2023, 11: 1236384
|
| [41] |
Steinfeldt T, Könen-Waisman S, Tong L, Pawlowski N, Lamkemeyer T, Sibley LD, Hunn JP, Howard JC. Phosphorylation of mouse immunity-related GTPase (IRG) resistance proteins is an evasion strategy for virulent Toxoplasma gondii. PLoS Biology., 2010, 8(12): e1000576
|
| [42] |
Su C, Shwab EK, Zhou P, Zhu XQ, Dubey JP. Moving toward an integrated approach to molecular detection and identification of Toxoplasma gondii. Parasitology, 2010, 137(1): 1-11
|
| [43] |
Su C, Zhang X, Dubey JP. Genotyping of Toxoplasma gondii by multilocus PCR-RFLP markers: A high resolution and simple method for identification of parasites. International Journal for Parasitology., 2006, 36(7): 841-848
|
| [44] |
Velmurugan GV, Dubey JP, Su C. Genotyping studies of Toxoplasma gondii isolates from Africa revealed that archetypal clonal lineages predominate, as in North America and Europe. Veterinary Parasitology., 2008, 155(3–4): 314-318
|
| [45] |
Xin S, Jiang N, Yang L, Zhu N, Huang W, Li J, Zhang L, Su C, Yang Y. Isolation, genotyping and virulence determination of a Toxoplasma gondii strain from nonhuman primate from China. Transboundary and Emerging Diseases., 2022, 69(2): 919-925
|
| [46] |
Yang, F., K. X. Li, C. Z. Xu, F. Shan, W. Chen, S. M. Peng, W. P. Li, and G. Q. Li. 2017. Multilocus genotyping of Toxoplasma gondii isolated from a captive ring-tailed lemur (Lemur catta) in China. Chinese journal of wildlife 38: 187–193. https://doi.org/10.19711/j.cnki.issn2310-1490.2017.02.006. (In Chinese).
|
| [47] |
Yang L, Ren H, Zhu N, Xin S, Mao G, Ma Y, Li J, Liang Q, Yang Y. Isolation and genetic characterization of Toxoplasma gondii from a patas monkey (Erythrocebus patas) in China. Genes, 2023, 14(8): 1606
|
| [48] |
Yang, Y., Y. Ying, S. K. Verma, A. B. Cassinelli, O. C. Kwok, H. Liang, A. K. Pradhan, X. Q. Zhu, C. Su, J. P. Dubey. 2015. Isolation and genetic characterization of viable Toxoplasma gondii from tissues and feces of cats from the central region of China. Veterinary parasitology. 211(3-4): 283–288. https://doi.org/10.1016/j.vetpar.2015.05.006.
|
Funding
Natural Science Foundation of Guangdong Province(2026A1515010492)
National Natural Science Foundation of China(31972707)
RIGHTS & PERMISSIONS
The Author(s)
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