Genotyping of Toxoplasma gondii in a lethal toxoplasmosis outbreak affecting captive howler monkeys (Alouatta sp.)

Toxoplasmosis outbreak caused by north American genotypes in captive black-tufted marmosets in southern Brazil

In this study, we describe an outbreak of toxoplasmosis in an enclosure of five Callithrix penicillata in Southern Brazil. The marmosets were found dead and submitted to necropsy and histopathology. Liver, spleen, and lungs were frozen and sent for polymerase chain reaction (PCR) and nested-PCR-restriction fragment length polymorphism (RFLP) genotyping of Toxoplasma gondii. Necropsy revealed a liver with a lobular pattern, along with diffusely congested lungs, spleen, and kidneys, and hemorrhage in the mesenteric lymph nodes. Mild-to-moderate, multifocal, necrotic hepatitis and splenitis, multifocal lymphoplasmacytic myocarditis, and moderate, diffuse necrohemorrhagic lymphadenitis were observed. T. gondii tachyzoites were in all the organs mentioned. The detected strains were closely related with the isolates TgWtdUs10, TgSoUs39, and TgShUs2, which were originally found in non-primate species all in the United States of America. This is an unprecedented report of North American strains causing mortality in captive individuals of the species Callithrix penicillata in the Southern Brazil.

Lessons from a Multilaboratorial Task Force for Diagnosis of a Fatal Toxoplasmosis Outbreak in Captive Primates in Brazil

Toxoplasmosis is an important zoonotic disease caused by the parasite Toxoplasma gondii and is especially fatal for neotropical primates. In Brazil, the Ministry of Health is responsible for national epizootic surveillance, but some diseases are still neglected. Here, we present an integrated investigation of an outbreak that occurred during the first year of the COVID-19 pandemic among eleven neotropical primates housed at a primatology center in Brazil. After presenting non-specific clinical signs, all animals died within four days. A wide range of pathogens were evaluated, and we successfully identified T. gondii as the causative agent within four days after necropsies. The liver was the most affected organ, presenting hemorrhage and hepatocellular necrosis. Tachyzoites and bradyzoite cysts were observed in histological examinations and immunohistochemistry in different organs; in addition, parasitic DNA was detected through PCR in blood samples from all specimens evaluated. A high prevalence of Escherichia coli was also observed, indicating sepsis. This case highlights some of the obstacles faced by the current Brazilian surveillance system. A diagnosis was obtained through the integrated action of researchers since investigation for toxoplasmosis is currently absent in national guidelines. An interdisciplinary investigation could be a possible model for future epizootic investigations in animals.

Case report: Urbanized non-human primates as sentinels for human zoonotic diseases: a case of acute fatal toxoplasmosis in a free-ranging marmoset in coinfection with yellow fever virus

Free-ranging non-human primates (NHP) can live in anthropized areas or urban environments in close contact with human populations. This condition can enable the emergence and transmission of high-impact zoonotic pathogens. For the first time, we detected a coinfection of the yellow fever (YF) virus with Toxoplasma gondii in a free-ranging NHP in a highly urbanized area of a metropolis in Brazil. Specifically, we observed this coinfection in a black-tufted marmoset found dead and taken for a necropsy by the local health surveillance service. After conducting an epidemiological investigation, characterizing the pathological features, and performing molecular assays, we confirmed that the marmoset developed an acute fatal infection caused by T. gondii in coinfection with a new YF virus South American-1 sub-lineage. As a result, we have raised concerns about the public health implications of these findings and discussed the importance of diagnosis and surveillance of zoonotic agents in urbanized NHPs. As competent hosts of zoonotic diseases such as YF and environmental sentinels for toxoplasmosis, NHPs play a crucial role in the One Health framework to predict and prevent the emergence of dangerous human pathogens.

Isolation and genetic characterization of Toxoplasma gondii from a captive black-and-gold howler monkey (Alouatta caraya Humboldt, 1812) in Brazil

Toxoplasma gondii was isolated in mice from different tissues of a captive black-and-gold howler monkey (Alouatta caraya) kept in a colony at the Primatology Center of Rio de Janeiro State, Brazil, and it was genotypically characterized based on using PCR-RFLP and Microsatellite Analysis (MS), later on. T. gondii was successfully isolated from inocula deriving from heart, liver and tissue pool (heart, liver, lungs, axillary lymph nodes and cerebellum) samples. The isolate was named TgBgHmBrRJ1. The high virulence of the aforementioned strain was observed in infected mice. Non-archetypal genotype (ToxoDB PCR-RFLP #206) was obtained through PCR-RFLP. This genotype had been previously described in 12 isolates from different hosts, also in Southeastern Brazil, a fact that indicates likely high circulation of this genotype in this region. The isolate was also classified as non-archetypal, based on MS genotyping, as well as presented genotypic identity close to that of strains isolated from free-range non-symptomatic chickens (TgCkBr244,245,278,279) in Espírito Santo State. It is worth emphasizing that despite the large number of reports about clinical toxoplasmosis in neotropical primates in Brazil, this is just the second isolate of this parasite ever reported in this group of animals.

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Toxoplasma gondii was isolated in a murine model from Alouatta caraya in captivity.

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An intermediate virulence of the isolated in the infected murine model was verified.

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A non-archetypal genotype (ToxoDB PCR-RFLP #206) was obtained by PCR-RFLP.

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This is the second isolation of T. gondii from a non-human primate in Brazil.

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For the first time, this genotype was associated with clinical disease in a host.

Pathology and epidemiology of fatal toxoplasmosis in free-ranging marmosets (Callithrix spp.) from the Brazilian atlantic forest

Toxoplasmosis is an important zoonotic disease that affects a wide range of warm-blooded host species. Neotropical primates (New World Primates; NWP) are highly susceptible, developing a lethal acute systemic disease. Toxoplasmosis in free-ranging NWP is poorly described, with only a few studies based on serosurveys. Herein we performed a retrospective study focusing on the epidemiology and pathology of toxoplasmosis among 1,001 free-ranging marmoset (Callithrix spp.) deaths from the Brazilian Atlantic Forest. This study included marmosets necropsied at the Instituto Municipal de Medicina Veterinária Jorge Vaitsman (IJV) from January 2017 to July 2019, which were found dead from all regions in the State of Rio de Janeiro. Histopathology, immunohistochemistry, and transmission electron microscopy were performed to better characterize toxoplasmosis in this free-ranging population. All samples were also tested for Yellow Fever Virus (YFV) RT-qPCR by the official diagnostic service. A total of 1,001 free-ranging marmosets were included in this study, with 16 (1.6%) cases of lethal Toxoplasma gondii infections identified both as individual cases and in outbreaks. Presence of infection was not associated with sex, age, geographical distribution, or year of death, and no co-infection with YFV was observed. The main pathological feature in these cases was random necrotizing hepatitis with detection of intralesional T. gondii zoites in all infected cases. Interstitial pneumonia rich in alveolar foamy macrophages and fibrin deposition, necrotizing myocarditis and necrotizing splenitis were also pathological features in affected marmosets. Therefore, toxoplasmosis was considered the cause of death in 1.6% of free-ranging marmosets in this retrospective series, including some cases associated with outbreaks. Necrotizing random hepatitis was a consistent pathological finding in affected cases and sampling of liver should be ensured from Callitrichid post mortem cases.

Subacute multisystemic toxoplasmosis in a captive black-and-gold howler monkey (Alouatta caraya) indicates therapy challenging

A 10-year-old black howler monkey presented with a 36-day subacute clinicopathological picture of fever, prostration, inappetence, intestinal hypomotility, and emaciation. Therapy was trimethoprim-sulfamethoxazole with streptomycin. The liver, lungs, lymph nodes, and spleen presented lesions. Toxoplasma gondii isolation and PCR determined the diagnosis, and indirect fluorescent antibody tests confirmed an increase in antibody titers.

Parasites of Free-Ranging and Captive American Primates: A Systematic Review

The diversity, spread, and evolution of parasites in non-human primates (NHPs) is a relevant issue for human public health as well as for NHPs conservation. Although previous reviews have recorded information on parasites in NHPs (Platyrrhines) in the Americas, the increasing number of recent studies has made these inventories far from complete. Here, we summarize information about parasites recently reported in Platyrrhines, attempting to build on earlier reviews and identify information gaps. A systematic literature search was conducted in PubMed, ISI Web of Science, and Latin American and Caribbean Health Sciences Literature (LILACS), and following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Ninety-three studies were included after the screening process. Records for 20 genera of NHPs, including 90 species were found. Most of the studies were conducted on captive individuals (54.1%), and morphological approaches were the most used for parasite identification. The most commonly collected biological samples were blood and stool, and Protozoa was the most frequent parasite group found. There is still scarce (if any) information on the parasites associated to several Platyrrhine species, especially for free-ranging populations. The use of molecular identification methods can provide important contributions to the field of NHPs parasitology in the near future. Finally, the identification of parasites in NHPs populations will continue to provide relevant information in the context of pervasive habitat loss and fragmentation that should influence both human public health and wildlife conservation strategies.