Recent epidemiologic, clinical, and genetic diversity of Toxoplasma gondii infections in non-human primates

Application potential of arecoline hydrobromide for anti-Toxoplasma gondii

Although long-term chewing areca nut may cause cancer, it is very feasible to treat human or livestock diseases in a short period of time. In this study, arecoline hydrobromide (AH), which is extracted from Areca catechu, significantly inhibited the proliferation of tachyzoites ofToxoplasma gondii (T. gondii) in vitro and in vivo. Specially,in vivo AH effectively resisted liver damage originate fromT. gondii. Furthemore, the survival and safety evaluation outcome indicated that AH can prolong survival period of mice infected with T. gondii at non-toxic and side-effect dose. Based on these advantages, AH is a candidate compound with great potential for the treatment of T. gondii infection and it may be used clinically in the future.

Insights into the threats of toxoplasmosis for free-ranging black-tufted marmosets living in our neighborhood

Toxoplasmosis is a globally significant zoonotic disease with the potential to severely impact wild animal populations. Neotropical non-human primates (NHPs), particularly callitrichids, are highly susceptible, often experiencing fatal outcomes. This study examines toxoplasmosis in free-ranging black-tufted marmosets (Callithrix penicillata) in anthropogenic environments of Central Brazil, analyzing epidemiological and pathological data from 2017 to 2022. A retrospective review of 1095 NHP deaths identified a 9.2% prevalence (101/1,095) of acute fatal toxoplasmosis (AFT) in black-tufted marmosets across Central Brazil and 10.3% (53/515) within the federal district (FD). Necropsied marmosets from the FD showed an estimated AFT prevalence of 50.7% and a lethality rate of 20.3%. AFT cases were linked to outbreaks and isolated incidents, with a likely seasonal peak during the dry season. Pathological findings included severe hepatic damage, splenitis, interstitial pneumonia, and myocarditis. Immunohistochemistry and qPCR confirmed Toxoplasma gondii infection, with the highest parasite loads in the spleen and liver. Given the anthropogenic pressures of habitat fragmentation, urbanization, and T. gondii exposure, this study advances the understanding of toxoplasmosis as an emerging disease in wild marmosets. Findings of this study establish a critical foundation for conservation strategies and insights into toxoplasmosis dynamics in free-ranging NHPs living in our neighborhood.

Occurrence of Toxoplasma gondii in Three Tamarin Species (Saguinus geoffroyi, Saguinus oedipus, and Leontocebus fuscicollis) Ex Situ in Colombia

BACKGROUND

Toxoplasmosis, caused by Toxoplasma gondii, is a zoonotic disease affecting public health and wildlife conservation, including nonhuman primates. This study evaluated the presence of T. gondii in three neotropical tamarin species (Leontocebus fuscicollis, Saguinus geoffroyi and Saguinus oedipus) at Barranquilla Zoo, Colombia.

METHODS

A retrospective analysis (2017-2022) was conducted on 17 tamarins. Clinical evaluations and blood samples were used to detect IgG antibodies via latex agglutination test. Necropsies and histopathological analyses were used to assess organ lesions associated with T. gondii.

RESULTS

In 2017, 35% (6/17) of the participants tested seropositive, increasing to 100% (13/13) by 2022. Antibody titer fluctuations were noted, with significant increases in female S. oedipus. Four deaths occurred, two linked to active or chronic infections. Stray cats and rodents in the zoo were identified as possible transmission vectors.

CONCLUSIONS

This study highlights T. gondii exposure to tamarins, associated mortality, and diagnostic challenges. Recommendations include stray cat management, pest control, and the exploration of vaccines to reduce transmission risks.

The Wildcat That Lives in Me: A Review on Free-Roaming Cats (Felis catus) in Brazil, Focusing on Research Priorities, Management, and Their Impacts on Cat Welfare

Domestic cats (Felis catus) currently occupy the 38th place in the Global Invasive Species Database. Free-roaming cats potentially have broad-ranging impacts on wildlife, occupying most terrestrial environments globally as house pets, strays, or feral animals. In Australia, for example, cats are responsible for the decline in many vertebrate populations and extinction of several native mammals. However, in Brazil, few studies have explored either direct impacts of predation on wildlife, or other indirect impacts, such as competition for resources, niche overlap, hybridization, and disease transmission. In this review, we summarize and discuss 34 original research reports, published between 2001 and 2020, on impacts of free-roaming cats in Brazil. We briefly contextualize the history of cat domestication and present that, in Brazil, more studies have focused on the potential of free-roaming cats to transmit disease than to exert impacts via predation or competition on wildlife. More studies were conducted in Brazilian mainland areas (n = 23)-notably in Atlantic Forest-than on islands (n = 11). The review highlights potential impacts of cats on wildlife. We also discuss how control management strategies can affect the welfare of domestic cats, identifying potential knowledge gaps as well as opportunities for future research. Finally, understanding risks of cat predation is necessary to inform future measures to mitigate impacts on wildlife, without neglecting cat welfare.

Serological evidence of exposition to Toxoplasma gondii in Saimiri spp. kept in a research institution as biomodels in Rio de Janeiro

Anti-Toxoplasma gondii antibodies were investigated in 125 Saimiri spp. kept at a research institute. A total of 12% of primates tested positive, all of which were Saimiri sciureus. These results highlight the need to minimize the possibility of this protozoan's circulation, which can lead to fulminant infection in these animals.

Rhoptry proteins affect the placental barrier in the context of Toxoplasma gondii infection: Signaling pathways and functions

Toxoplasma gondii is an opportunistic and pathogenic obligate intracellular parasitic protozoan that is widespread worldwide and can infect most warm-blooded animals, seriously endangering human health and affecting livestock production. Toxoplasmosis caused by T. gondii infection has different clinical manifestations, which are mainly determined by the virulence of T. gondii and host differences. Among the manifestations of this condition, abortion, stillbirth, and fetal malformation can occur if a woman is infected with T. gondii in early pregnancy. Here, we discuss how the T. gondii rhoptry protein affects host pregnancy outcomes and speculate on the related signaling pathways involved. The effects of rhoptry proteins of T. gondii on the placental barrier are complex. Rhoptry proteins not only regulate interferon-regulated genes (IRGs) to ensure the survival of parasites in activated cells but also promote the spread of worms in tissues and the invasive ability of the parasites. The functions of these rhoptry proteins and the associated signaling pathways highlight relevant mechanisms by which Toxoplasma crosses the placental barrier and influences fetal development and will guide future studies to uncover the complexity of the host-pathogen interactions.

Fatal toxoplasmosis in a captive squirrel monkey (Saimiri boliviensis) in Portugal

New World monkeys are especially vulnerable to develop severe clinical manifestations and succumb to acute toxoplasmosis. This study aimed to describe the histopathological findings and genotypic characterization of the Toxoplasma gondii strain involved in a lethal case occurring in a zoo-housed black-capped squirrel monkey (Saimiri boliviensis) in Portugal. Cyst-like structures suggestive of Sarcocystidae parasites and acute injuries in liver and brain were observed by light microscopy examination. By immunohistochemistry, calprotectin, T. gondii antigen and Iba1 antigen had a positive signaling in lung, liver and brain tissues. Toxoplasma gondii B1, ITS1 and 529 repetitive element fragments amplifications together with the genotyping of 13 microsatellite markers confirmed a systemic T. gondii infection linked to a non-clonal type II strain. This description is consistent to the majority T. gondii strains circulating in Europe.

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 Patas Monkey (Erythrocebus patas) in China

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.

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.

•

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

•

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

•

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

•

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

•

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

Toxoplasmosis in Captive Ring-Tailed Lemurs (Lemur catta)

Toxoplasma gondii is one of the most common protozoan parasites and is widely present in all warm-blooded animals. Although clinical disease is uncommon, some species, including ring-tailed lemurs (Lemur catta), have been found to develop acute and lethal toxoplasmosis. The aim of this study was to describe the pathologic, immunohistochemical, serological, and molecular findings of an outbreak of fatal toxoplasmosis in three captive ring-tailed lemurs in Central Italy in 2009. The animals died acutely within few days. The necropsy was immediately performed; necrotic lesions in the spleen, liver, and kidney, as well as interstitial pneumonia, were found histologically. All animals had high titers of anti-T. gondii-specific antibodies (1:1280 IgM and 1:640 IgG) according to a modified agglutination test (MAT) and immunohistochemistry showed scattered tachyzoites in the target organs. Diagnosis was confirmed by PCR and clonal type II was identified. In addition, the seven co-habiting lemurs were seronegative. This paper reports the first outbreak of acute disseminated toxoplasmosis in captive ring-tailed lemurs in Italy. These findings confirm the high susceptibility of this endangered species to toxoplasma infection, which may be considered a further threat to captive population viability.